Method and system for recovering acidic gases

Abstract

This invention provides a method for recovering acidic gases such as carbon dioxide using a simple process. [Solution] The method for recovering acidic gas includes an adsorption step of bringing a raw material gas G1 containing acidic gas into contact with an adsorbent 11 to adsorb the acidic gas contained in the raw material gas G1 onto the adsorbent 11, and a desorption step of desorbing the adsorbed gas G2 containing acidic gas from the adsorbent 11 that has adsorbed the acidic gas. In the desorption step, the adsorbent 11 is housed in a case 12 and brought into contact with a first liquid F1 having a temperature higher than room temperature.

Description

[Technical Field]

[0001] This invention relates to a method for recovering acidic gases and a system for recovering acidic gases. [Background technology]

[0002] In recent years, technologies for directly separating and recovering carbon dioxide contained in the atmosphere and exhaust gases (Direct Air Capture: DAC) have attracted attention. For example, Patent Document 1 describes a method for separating gaseous carbon dioxide from a gas mixture such as the atmosphere, which contains gaseous carbon dioxide and gases other than carbon dioxide, by adsorption and desorption using an adsorbent. In the method described in Patent Document 1, carbon dioxide is recovered from the atmosphere by filling the chamber with water vapor to displace oxygen, and then heating the adsorbent with a heat exchanger. The method described in Patent Document 1 is classified as an SA-VSA (Steam Assist Vacuum Swing Adsorption) method. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 6622302 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The present invention aims to provide an acid gas recovery method and recovery system that can recover acid gases such as carbon dioxide in a simple process. [Means for solving the problem]

[0005] The present invention An adsorption step in which a raw material gas containing an acidic gas is brought into contact with an adsorbent, and the acidic gas contained in the raw material gas is adsorbed onto the adsorbent, The process includes a desorption step of desorbing the adsorbed gas containing the acidic gas from the adsorbent material that has adsorbed the acidic gas, A method for recovering acidic gases, wherein in the desorption step, the adsorbent is housed in a case and brought into contact with a first liquid having a temperature higher than room temperature. To provide.

[0006] From another perspective, the present invention is An acid gas recovery system comprising: an adsorbent that, while adsorbing an acid gas, comes into contact with a first liquid having a temperature higher than room temperature to desorb the acid gas; and a case for containing the adsorbent and bringing it into contact with the first liquid; To provide. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an acid gas recovery method and recovery system that can recover acid gases such as carbon dioxide in a simple process. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a recovery system that can be used in the acid gas recovery method of the present invention. [Figure 2] This is a schematic perspective view showing an example of an adsorbent material. [Figure 3] This is a schematic perspective view showing another example of an adsorbent. [Figure 4] This is a schematic diagram of a modified example 1 of the recovery system. [Figure 5] This is a schematic diagram of a modified example 2 of the recovery system. [Figure 6] This is a schematic diagram of a modified example 3 of the recovery system. [Figure 7] This is a schematic diagram of a modified example 4 of the recovery system. [Modes for carrying out the invention]

[0009] A method for recovering acidic gas according to a first aspect of the present invention is: A adsorption step of bringing a raw material gas containing an acid gas into contact with an adsorbent to adsorb the acid gas contained in the raw material gas onto the adsorbent; a desorption step of desorbing an adsorbed gas containing the acid gas from the adsorbent that has adsorbed the acid gas, and includes: In the desorption step, the adsorbent is brought into contact with a first liquid having a temperature higher than room temperature in a state where the adsorbent is housed in a case.

[0010] In a second aspect of the present invention, for example, in the method for recovering an acid gas according to the first aspect, in the desorption step, the adsorbent is brought into contact with the first liquid by immersing the adsorbent in the first liquid inside the case.

[0011] In a third aspect of the present invention, for example, in the method for recovering an acid gas according to the first or second aspect, the desorption step includes supplying the first liquid to the case in a state where the adsorbent is housed.

[0012] In a fourth aspect of the present invention, for example, in the method for recovering an acid gas according to any one of the first to third aspects, the adsorption step is carried out inside the case, and the desorption step includes discharging the raw material gas existing inside the case to the outside of the case while supplying the first liquid to the case in a state where the adsorbent is housed.

[0013] In a fifth aspect of the present invention, for example, in the method for recovering an acid gas according to the first or second aspect, the desorption step includes supplying a second liquid having a temperature equal to or lower than room temperature to the case in a state where the adsorbent is housed, and heating the second liquid supplied to the case.

[0014] In a sixth aspect of the present invention, for example, the method for recovering an acid gas according to any one of the first to fifth aspects further includes a cooling step of cooling the adsorbent from which the acid gas has been desorbed.

[0015] In a seventh embodiment of the present invention, for example, in the method for recovering acidic gas according to any one of the first to sixth embodiments, the adsorption step and the desorption step are carried out inside the same case.

[0016] In an eighth aspect of the present invention, for example, in a method for recovering an acidic gas according to any one of the first to sixth aspects, the adsorption step is performed outside the case, and the method further includes a containment step between the adsorption step and the desorption step in which the adsorbent material that has adsorbed the acidic gas is contained inside the case.

[0017] In the ninth embodiment of the present invention, for example, in the method for recovering acidic gas according to any one of the first to eighth embodiments, the adsorbent includes a polymer having an amino group.

[0018] In the tenth embodiment of the present invention, for example, in the method for recovering acidic gas according to the ninth embodiment, the polymer has constituent units derived from an epoxy compound and constituent units derived from an amine compound.

[0019] In the eleventh aspect of the present invention, for example, the acidity according to any one of the first to tenth aspects. In the gas recovery method, the temperature of the first liquid is 40°C or higher.

[0020] The acid gas recovery system according to the twelfth aspect of the present invention is: The device comprises an adsorbent that, while adsorbing an acidic gas, comes into contact with a first liquid having a temperature higher than room temperature to desorb the acidic gas, and a case that houses the adsorbent and brings the adsorbent into contact with the first liquid.

[0021] In a thirteenth aspect of the present invention, for example, the acid gas recovery system according to the twelfth aspect further comprises a first liquid supply path for supplying the first liquid to the case.

[0022] In a fourteenth aspect of the present invention, for example, an acid gas recovery system according to a twelfth or thirteenth aspect further comprises a raw material gas supply path for supplying a raw material gas containing the acid gas to the case, and a raw material gas discharge path for discharging the raw material gas present inside the case to the outside of the case.

[0023] In a 15th embodiment of the present invention, for example, the acid gas recovery system according to the 12th embodiment further comprises a second liquid supply path that supplies a second liquid having a temperature below room temperature to the case, and a heating unit that heats the second liquid supplied to the case to produce the first liquid.

[0024] In a sixteenth aspect of the present invention, for example, an acid gas recovery system according to any one of the twelfth to fifteenth aspects further comprises a cooling water supply path for supplying cooling water to the case.

[0025] In a 17th aspect of the present invention, for example, an acid gas recovery system according to any one of the 12th to 16th aspects further comprises a pre-case for housing the adsorbent material when performing an adsorption mode in which the acid gas is adsorbed onto the adsorbent material, and a moving mechanism for moving the adsorbent material that has adsorbed the acid gas into the interior of the case.

[0026] The details of the present invention will be described below, but the following description is not intended to limit the present invention to any particular embodiment.

[0027] [Recovery System] Figure 1 is a schematic diagram of the acid gas recovery system 100 of this embodiment. The recovery system 100 includes an adsorbent 11 and a case 12 capable of housing the adsorbent 11. The case 12 is for contacting the adsorbent 11 with a first liquid F1 having a temperature higher than room temperature (25°C) while the adsorbent 11 is housed within it. The adsorbent 11, while adsorbing the acid gas contained in the raw material gas G1, contacts the first liquid F1 to desorb the acid gas. By desorbing the acid gas, the adsorbent 11 is regenerated. Desorbed gas (adsorbed gas) G2 containing the acid gas desorbed from the adsorbent 11 is released from the case 12. The dashed arrow in the case 12 shown in Figure 1 indicates an example of the flow direction of the raw material gas G1. The same applies to other drawings.

[0028] According to the recovery system 100, acidic gases can be removed from the adsorbent 11 by a simple process, that is, by directly contacting the first liquid F1 with the adsorbent 11 while it is housed in the case 12. Since the recovery system 100 uses a direct heating method, even if the thermal conductivity of the adsorbent 11 is low, for example, thermal energy can be imparted to the adsorbent 11 in a short time.

[0029] In this embodiment, the adsorbent 11 is immersed in the first liquid F1 inside the case 12. The adsorbent 11 is then brought into contact with the first liquid F1. With this configuration, it is possible to easily isolate the adsorbent 11 from gas (for example, the raw material gas G1 remaining inside the case 12) and heat the adsorbent 11. In addition, it can be expected that this will also have the effect of removing deposits and other substances adhering to the surface of the adsorbent 11.

[0030] The first liquid F1 may be circulated inside case 12. In this case, a circulation mechanism (not shown), such as a stirring blade, may be provided inside case 12. The first liquid F1 may also be allowed to remain stagnant inside case 12.

[0031] The recovery system 100 is suitable for the Temperature Swing Adsorption (TSA) method.

[0032] As described above, in this specification, the first liquid F1 is a liquid having a temperature higher than room temperature (25°C). The lower limit of the temperature of the first liquid F1 may be, for example, 30°C or higher, 40°C or higher, 60°C or higher, 80°C or higher, 90°C or higher, 95°C or higher, or even 98°C or higher. The upper limit of the temperature of the first liquid F1 may be, for example, 100°C or lower, or 130°C or lower. As the first liquid F1, for example, water, a mixed liquid of water and ethylene glycol or propylene glycol, etc. can be used. When the first liquid F1 is water, the upper limit of the temperature of the first liquid F1 is 100°C or lower. When the first liquid F1 is a mixed liquid of water and ethylene glycol or propylene glycol, the upper limit of the temperature of the first liquid F1 is 130°C or lower.

[0033] In this specification, the mode in which the acidic gas is desorbed from the adsorbent 11 is referred to as the "desorption mode." In the desorption mode, the adsorbent 11 comes into contact with the first liquid F1 inside the case 12 and desorbs the acidic gas. The adsorbed gas G2 containing the acidic gas is discharged from the outlet of the case 12.

[0034] In this specification, the mode in which the adsorbent 11 adsorbs the acidic gas contained in the raw material gas G1 is referred to as the "adsorption mode." In the adsorption mode, the adsorbent 11 may come into contact with the raw material gas G1 inside the case 12 and adsorb the acidic gas contained in the raw material gas G1. In this case, the outlet of the case 12 discharges a non-adsorbed gas G3, which has a lower acidic gas content than the raw material gas G1.

[0035] The raw material gas G1 preferably contains, for example, an acidic gas, and further contains other gases other than acidic gases. The raw material gas G1 is preferably the atmosphere. The raw material gas G1 may also be a combustion gas or the like.

[0036] The acidic gas content in the raw material gas G1 is not particularly limited, and is, for example, 0.01 vol% (100 vol ppm) or more, preferably 0.04 vol% (400 vol ppm) or more, and may also be 0.1 vol% or more. The upper limit of the acidic gas content in the raw material gas G1 is not particularly limited, and is, for example, 20 vol%. The pressure of the raw material gas G1 is typically equal to the atmospheric pressure in the operating environment of the recovery system 100.

[0037] Examples of acidic gases include carbon dioxide, hydrogen sulfide, carbonyl sulfide, sulfur oxides (SOx), hydrogen cyanide, nitrogen oxides (NOx), etc., with carbon dioxide being preferred.

[0038] In this embodiment, when the desorption mode is performed, the adsorbent 11 that has adsorbed the acidic gas is housed in the case 12. When the adsorption mode is performed, the regenerated adsorbent 11 from which the acidic gas has been desorbed is housed in the case 12.

[0039] In this embodiment, in the adsorption mode and the desorption mode, the adsorbent 11 is the same case 1 It is housed in case 2. In other words, in the recovery system 100, the adsorption mode and the desorption mode are carried out inside a single case 12. With this configuration, for example, it is easier to switch between the adsorption mode and the desorption mode compared to a case where there are separate cases for the adsorption mode and the desorption mode. Also, since there is no need to prepare separate cases for each mode, the recovery system 100 can be made compact.

[0040] Furthermore, in this embodiment, the desorption mode can be performed without creating a vacuum inside the case 12, allowing the case 12 to have a simple configuration. Also, the shape of the case 12 can be freely designed to match the shape of the adsorbent 11. Examples of materials for the case 12 include resin and metal. As shown in Figure 1, the shape of the case 12 may be a rectangular parallelepiped. However, the shape of the case 12 is not limited to a rectangular parallelepiped. The shape of the case 12 may be, for example, cylindrical.

[0041] The recovery system 100 includes a raw material gas supply path 31. The raw material gas supply path 31 is connected to the raw material gas inlet 12a of the case 12 and is a path for supplying raw material gas G1 to the case 12. As described above, the raw material gas G1 is preferably atmospheric air. When the raw material gas G1 is atmospheric air, the raw material gas supply path 31 may have an air intake port 31a that opens into the atmosphere, or it may be configured to continuously draw in atmospheric air from the air intake port 31a. As shown in Figure 1, the air intake port 31a may be provided with a blowing mechanism 31b, such as a fan, for supplying atmospheric air to the raw material gas supply path 31. The raw material gas supply path 31 may be connected to, for example, a tank (not shown) that stores the raw material gas G1. The raw material gas supply path 31 is provided with an on / off valve 41. Although not shown, the raw material gas supply path 31 may further be provided with a flow control valve to adjust the flow rate of the raw material gas G1 flowing through the raw material gas supply path 31.

[0042] During the adsorption mode, the raw material gas G1 is supplied to case 12, thereby replacing the first liquid F1 remaining in case 12 with the raw material gas G1. As a result, the adsorbent 11 comes into contact with the raw material gas G1 and can adsorb the acidic gases contained in the raw material gas G1.

[0043] In the example shown in Figure 1, the raw material gas supply path 31 is connected to a raw material gas inlet 12a located on the upper side of the rectangular parallelepiped case 12. With this configuration, for example, in the adsorption mode, the raw material gas G1 can be supplied evenly to the adsorbent 11 housed in the case 12. However, the connection location of the raw material gas supply path 31 is not limited to the example shown in Figure 1. For example, the raw material gas supply path 31 may be connected to the entire side of the rectangular parallelepiped case 12.

[0044] The recovery system 100 includes an adsorbent gas discharge path 32. The adsorbent gas discharge path 32 is connected to the gas outlet 12b of the case 12 and is a path for discharging the adsorbent gas G2 from the case 12. The adsorbent gas discharge path 32 may be connected to a tank (not shown) for recovering the adsorbent gas G2. The adsorbent gas discharge path 32 may be connected to a condenser (not shown) for increasing the concentration of the adsorbent gas G2. The condenser may be connected to the recovery tank. The adsorbent gas discharge path 32 is provided with an on / off valve 42. Although not shown, the adsorbent gas discharge path 32 may further be provided with a flow control valve to adjust the flow rate of the adsorbent gas G2 flowing through the adsorbent gas discharge path 32.

[0045] In the example shown in Figure 1, the adsorbed gas discharge path 32 is connected to a gas outlet 12b located on the upper surface of the rectangular parallelepiped case 12. With this configuration, for example, in the desorption mode, the adsorbed gas G2 containing acidic gas desorbed from the adsorbent 11 can be easily discharged to the outside of the case 12. However, the connection position of the adsorbed gas discharge path 32 is not limited to the example shown in Figure 1.

[0046] The recovery system 100 includes a non-adsorbent gas discharge path 33. The non-adsorbent gas discharge path 33 is connected to the gas outlet 12c of the case 12 and is a path for discharging non-adsorbent gas G3 from the case 12. The non-adsorbent gas discharge path 33 is, for example, open to the atmosphere. If the raw material gas G1 is the atmosphere, the non-adsorbent gas discharge path 33 may have a configuration that continuously draws in non-adsorbent gas G3. The non-adsorbent gas discharge path 33 may be connected to a tank (not shown) for recovering non-adsorbent gas G3. The non-adsorbent gas discharge path 33 is provided with an on / off valve 43. Although not shown, the non-adsorbent gas discharge path 33 may further be provided with a flow control valve to adjust the flow rate of non-adsorbent gas G3 flowing through the non-adsorbent gas discharge path 33.

[0047] In the example shown in Figure 1, the non-adsorbed gas discharge path 33 is connected to a gas outlet 12c provided on the upper surface of the rectangular parallelepiped case 12. With this configuration, for example, in the adsorption mode, the non-adsorbed gas G3 that was not adsorbed by the adsorbent 11 can be easily discharged to the outside of the case 12. However, the connection location of the non-adsorbed gas discharge path 33 is not limited to the example shown in Figure 1. For example, the non-adsorbed gas discharge path 33 may be connected to the entire side surface of the rectangular parallelepiped case 12.

[0048] The recovery system 100 includes a first liquid supply path 34. The first liquid supply path 34 is connected to the first liquid inlet 12d of the case 12 and is a path for supplying the first liquid F1 to the case 12. The first liquid supply path 34 is connected to, for example, the first liquid supply unit 20. The first liquid supply path 34 may be directly connected to the first liquid supply unit 20, or it may be configured to continuously supply the first liquid F1 from the first liquid supply unit 20 to the case 12. The first liquid supply path 34 is provided with an on-off valve 44. A liquid supply mechanism may be provided in the first liquid supply unit 20 and / or the first liquid supply path 34. Examples of liquid supply mechanisms include a mechanism that directly pressurizes the first liquid supply unit 20, a liquid supply pump provided in the first liquid supply path 34, and a mechanism that supplies the first liquid F1 from the first liquid supply unit 20 to the case 12 using gravity. In the example shown in Figure 1, a liquid supply pump 54 is provided upstream of the on-off valve 44. As the liquid transfer pump 54, for example, a pump for transferring high-temperature fluids can be used. Although not shown in the figures, the first liquid supply path 34 may also be provided with a flow control valve to adjust the flow rate of the first liquid F1 flowing through the first liquid supply path 34.

[0049] During the desorption mode, the first liquid F1 is supplied to case 12, thereby replacing the raw material gas G1 remaining in case 12 with the first liquid F1. As a result, the adsorbent 11 receives thermal energy from the first liquid F1 and can desorb the acidic gas.

[0050] In the example shown in Figure 1, the first liquid supply path 34 is connected to a first liquid inlet 12d provided on the side of the rectangular parallelepiped case 12. With this configuration, for example, in the desorption mode, the first liquid F1 can be supplied evenly to the adsorbent 11 housed in the case 12. However, the connection position of the first liquid supply path 34 is not limited to the example shown in Figure 1.

[0051] The configuration of the first liquid supply unit 20 is not particularly limited, as long as it can supply the first liquid F1 to the case 12. As shown in Figure 1, the first liquid supply unit 20 may include a tank 21 and a heater 22. The first liquid supply unit 20 may also be a first liquid generating device that generates the first liquid F1 by heating a second liquid F2, which is contained in the tank 21 and has a temperature below room temperature, with the heater 22. By supplying the first liquid F1 from the first liquid supply unit 20 to the case 12, the adsorbent 11 contained in the case 12 can be brought into contact with the first liquid F1 in the desorption mode.

[0052] As described above, in this specification, the second liquid F2 is a liquid having a temperature of room temperature (25°C) or lower. The upper limit of the temperature of the second liquid F2 may be, for example, 20°C or lower, 15°C or lower, or even 10°C or lower. The lower limit of the temperature of the second liquid F2 may be, for example, -30°C or higher. The temperature may be -20°C or higher, -10°C or higher, or even 0°C or higher. The second liquid F2 can be the same liquid as described for the first liquid F1. That is, the second liquid F2 can be, for example, water, or a mixture of water and ethylene glycol or propylene glycol. If the second liquid F2 is water, the lower limit of the temperature of the second liquid F2 is 0°C or higher. If the second liquid F2 is a mixture of water and ethylene glycol or propylene glycol, the lower limit of the temperature of the second liquid F2 is -30°C or higher.

[0053] Although not shown in the diagram, acidic gas may be recovered using the tank 21 of the first liquid supply unit 20. The method of recovering acidic gas in the tank 21 is not particularly limited. For example, acidic gas dissolved in the treated water F4 may be recovered by depressurizing the tank 21 using a depressurization mechanism. Acidic gas dissolved in the treated water F4 may be recovered by reheating the treated water F4 inside the tank 21 using a heating mechanism. Acidic gas dissolved in the treated water F4 may be recovered by vibrating the treated water F4 inside the tank 21 using a vibration mechanism such as an ultrasonic device. Acidic gas dissolved in the treated water F4 may be recovered by bubbling the treated water F4 inside the tank 21.

[0054] The recovery system 100 includes a drainage path 35. The drainage path 35 is connected to the drainage outlet 12e of the case 12 and is a path for discharging treated water F4 from the case 12. The treated water F4 is, for example, the first liquid F1 after use in the desorption mode. The drainage path 35 is connected to, for example, the first liquid supply unit 20. The drainage path 35 may be directly connected to the first liquid supply unit 20, or it may be configured to continuously supply treated water F4 from the case 12 to the first liquid supply unit 20. The drainage path 35 is provided with an on / off valve 45. Although not shown in the figures, the drainage path 35 may further be provided with a flow control valve to adjust the flow rate of treated water F4 flowing through the drainage path 35.

[0055] In the example shown in Figure 1, the drainage path 35 is connected to a drainage outlet 12e located on the lower surface of the rectangular parallelepiped case 12. With this configuration, for example, the first liquid F1 (treated water F4) used in the desorption mode can be easily discharged to the outside of the case 12. However, the connection position of the drainage path 35 is not limited to the example shown in Figure 1.

[0056] Each of the pathways of the recovery system 100 consists of, for example, metal or resin piping, unless otherwise specified.

[0057] The recovery system 100 further includes a controller 50 that controls each component of the recovery system 100. The controller 50 is a DSP (Digital Signal Processor) that includes, for example, an A / D conversion circuit, an input / output circuit, an arithmetic circuit, and a memory device. The controller 50 stores a program for properly operating the recovery system 100. For example, the controller 50 controls the operation of the first liquid supply path 34 to bring the adsorbent 11 into contact with the first liquid F1 in the desorption mode. For example, the controller 50 controls the operation of the raw material gas supply path 31 to bring the adsorbent 11 into contact with the raw material gas G1 in the adsorption mode.

[0058] The recovery system 100 may further include a switching mechanism (not shown) for switching between adsorption mode and desorption mode. The switching mechanism includes, for example, an on-off valve 41 located in the raw material gas supply path 31, an on-off valve 44 located in the first liquid supply path 34, and a controller 50. The controller 50 controls each valve, and by switching between the raw material gas supply path 31 and the first liquid supply path 34, the adsorption mode and desorption mode can be switched.

[0059] The recovery system 100 recovers oxygen (dissolved acid) contained in the first liquid F1 supplied to case 12. The system may further include a removal mechanism (not shown) for removing dissolved oxygen. The removal mechanism may, for example, involve bubbling an inert gas such as nitrogen into the first liquid F1 (or second liquid F2) inside the tank 21 of the first liquid supply unit 20 to expel dissolved oxygen.

[0060] Deoxygenated water may be used as the first liquid F1 (or second liquid F2).

[0061] [Adsorbent material] Figure 2 is a schematic perspective view showing an example of an adsorbent 11. The adsorbent 11A shown in Figure 2 is a structure comprising a main body 10 and a ventilation path 14. The ventilation path 14 functions as a path through which the raw material gas G1, first liquid F1, etc., pass. It is preferable that the adsorbent 11A is arranged such that the ventilation path 14 extends in the flow direction of the raw material gas G1, first liquid F1, etc. Typically, the adsorbent 11A is a honeycomb structure having a plurality of ventilation paths 14 extending in the same direction.

[0062] The main body portion 10 of the adsorbent material 11A typically has the shape of a sheet. The adsorbent material 11A may also include a support that supports the sheet-shaped main body portion 10.

[0063] As shown in Figure 2, the adsorbent 11A may comprise a unit 15 in which a corrugated body portion 10A and a flat body portion 10B are laminated. In the body portion 10A, a plurality of peaks 13a and a plurality of valleys 13b may be arranged alternately. In this case, a ventilation path 14 is formed between the peaks 13a or valleys 13b of the body portion 10A and the body portion 10B. Thus, the ventilation path 14 is surrounded by the body portions 10A and 11B.

[0064] The configuration of the adsorbent 11 is not limited to the examples shown in Figures 1 and 2.

[0065] Figure 3 is a schematic perspective view showing another example of the adsorbent 11. The adsorbent 11B shown in Figure 3 is a structure having a shape in which one unit 15 is wound around a central tube (not shown). Except for this, the configuration of the adsorbent 11B shown in Figure 3 is the same as the configuration of the adsorbent 11A shown in Figure 2. It is preferable that the adsorbent 11B is arranged so that the central tube extends in the flow direction of the raw material gas G1, first liquid F1, etc. in the case 12. The case 12 capable of housing the adsorbent 11B may be cylindrical (especially cylindrical). Because the unit 15 is wound around the central tube, in the main body 10A, the multiple peaks 13a and multiple valleys 13b are, in detail, arranged alternately in the circumferential direction of the central tube.

[0066] The adsorbent 11 is not particularly limited, as long as it can desorb acidic gases when in contact with the first liquid F1 and adsorb acidic gases contained in the raw material gas G1 when in contact with the raw material gas G1. Preferably, the adsorbent 11 is suitable for the TSA method. For example, the adsorbent 11 adsorbs acidic gases at room temperature (around 25°C) and desorbs the acidic gases by receiving thermal energy from the first liquid F1.

[0067] The material of the adsorbent 11 is not particularly limited, and examples include inorganic materials and organic materials. Examples of inorganic materials include metal oxides such as cerium oxide, zeolites, silica gel, and activated carbon. Examples of organic materials include polymer P having an amino group, and amine compounds other than polymer P. In the recovery system 100 of this embodiment, it is preferable that the adsorbent 11 contains polymer P having an amino group.

[0068] In DACs employing the TSA method, nanoparticles such as silica supporting amines are sometimes used as adsorbents. Conventionally, in order to avoid the elution of amines from the adsorbent, methods of indirectly heating the adsorbent with hot water were often employed. However, this In indirect heating methods, the degree of contact between the heat transfer surface and the adsorbent affects the heating performance. If the adsorbent swells or shrinks, the thermal conductivity between the adsorbent and the heat transfer surface may be impaired. To avoid such problems, it is conceivable to fix the adsorbent using adhesives, fasteners, etc., but this would complicate installation and replacement, which is undesirable. In contrast, in the recovery system 100 of this embodiment, in the desorption process, the adsorbent 11 is heated by bringing it into contact with a first liquid F1 having a temperature higher than room temperature while it is housed in the case 12. Therefore, even if the adsorbent 11 swells or shrinks, the impact on heating performance can be kept to a minimum. Consequently, there is no need to fix the adsorbent 11 to the case 12.

[0069] The adsorbent 11 containing polymer P having amino groups swells in water, but the elution of amines is kept low compared to conventional amine-based solid adsorbents. For example, when the adsorbent 11 is immersed in water at 25°C for 15 hours, the remaining amount of polymer P can be 90% or more. Therefore, the adsorbent 11 containing polymer P having amino groups is particularly suitable for the recovery system 100 of this embodiment, which employs a direct heating method.

[0070] The residual polymer P can be determined, for example, by the following method: A sample is prepared by punching out an adsorbent 11 (250 μm thick) to a size of 20 mm × 30 mm in an environment of 25°C and 50% humidity. The weight of the dry sample after vacuum drying at 100°C for 120 minutes is measured and this is taken as the polymer P content R1 in the dry state. If the adsorbent 11 contains a support, the weight of the support contained in the 20 mm × 30 mm × 250 μm thickness is subtracted to determine the polymer P content R1 (wt%) in the dry state. Next, the sample is immersed in water at 25°C for 15 hours. The weight of the dry sample after vacuum drying at 100°C for 120 minutes is measured and this is taken as the polymer P content R2 (wt%) after immersion. If the adsorbent 11 contains a support, the weight of the carrier contained in the 20 mm × 30 mm × 250 μm thickness is subtracted to determine the polymer P content R2 after immersion. The remaining percentage D of polymer P when the adsorbent 11 is immersed in water at 25°C for 15 hours can be calculated using the following formula (1). D=1-{(R1-R2) / R1}×100...(1)

[0071] The adsorbent material 11 is not limited to honeycomb structures such as the adsorbent materials 11A and 11B described above. For example, the adsorbent material 11 may be a block-shaped structure formed by stacking sheet-shaped adsorbent materials, or it may be an aggregate of bead-shaped adsorbent materials.

[0072] The adsorbent 11 may have a porous structure. For example, the adsorbent 11 may include a porous body S containing a polymer P as a sheet-like or block-like main body 10.

[0073] The porous body S preferably has a three-dimensional network skeleton containing the polymer P. The three-dimensional network skeleton may further contain other components other than the polymer P. As an example, in the porous body S, the above three-dimensional network skeleton extends continuously. The pores contained in the porous body S are preferably continuous pores formed continuously in three dimensions. The porous body S may have independent pores or may have through-holes penetrating the porous body S.

[0074] The porous body S preferably has an average pore diameter of 0.1 μm or more and 50 μm or less. The larger the average pore diameter of the porous body S, the more the adsorbent 11 can maintain the diffusion of the acidic gas without blocking the pores even when it contains water. The lower limit of the average pore diameter of the porous body S may be 0.2 μm or more, 0.3 μm or more, or even 0.5 μm or more. In this specification, the average pore diameter of the porous body S means the median diameter measured by the mercury intrusion method. The mercury intrusion method is performed under the condition of an initial pressure of 21 kPa using a commercially available pore size distribution analyzer (for example, AutoPore V9620 manufactured by Micromeritics).

[0075] The porous body S is 0.5 m 2 , 2 , 2 , , 2 , 2 / g or more and 100 m 2 / g or less preferably has a specific surface area. The larger the specific surface area of the porous body S, the larger the contact area with the acidic gas, so the rate of adsorbing the acidic gas increases. The lower limit of the specific surface area of the porous body S is 0.5 m 2 / g or more, 1.0 m 2 / g or more, 2.0 m 2 / g or more, 3.0 m 2 / g or more, 4.0 m 2 / g or more, 5.0 m 2 / g or more, 6.0 m 2 / g or more, 7.0 m 2 / g or more, or even 8.0 m 2 / g or more may be. The specific surface area of the porous body S means the BET (Brunauer-Emmett-Teller) specific surface area by nitrogen gas adsorption. The specific surface area of the porous body S can be measured by a method conforming to the provisions of JIS Z8830:2013.

[0076] The porous body S is 0.1 cm 3 / g or more 5.0cm 3 It is preferable to have a pore volume of 0.2 cm³ or less. The larger the pore volume of the porous body S, the better the diffusion of acidic gas within the pores, and therefore the rate of adsorption of acidic gas can increase. The lower limit of the pore volume of the porous body S is 0.2 cm³. 3 / g or more, 0.3cm 3 / g or more, 0.5cm 3 / g or more, 1.0cm 3 / g or more, and also 2.0cm 3 It may be greater than or equal to / g. The upper limit of the pore volume of the porous body S is 4.0 cm³. 3 It may be less than / g, and 3.0cm 3 The concentration may be less than or equal to / g. The pore volume of the porous body S can be measured by the mercury intrusion method. The mercury intrusion method is performed using a commercially available pore distribution analyzer (for example, the Autopore V9620 manufactured by Micromeristics) under an initial pressure of 21 kPa.

[0077] (Polymer P) The polymer P is preferably an amine polymer containing a constituent unit U1 derived from an epoxy monomer. This amine polymer includes, for example, a reaction product P1 from a group of compounds containing an amine monomer and an epoxy monomer.

[0078] The group of compounds for forming reactant P1 includes amine monomers and epoxy monomers, as described above. Reactant P1 may be, for example, a polymer of the group of monomers including amine monomers and epoxy monomers (particularly a polymer of amine monomers and epoxy monomers). Reactant P1 may also be a crosslinked product in which the amine monomer is crosslinked with the epoxy monomer.

[0079] Examples of amine monomers include ethylamine, ethylenediamine, 1,4-butylenediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, iminobispropylamine, bis(hexamethylene)triamine, 1,3,6-trisaminomethylhexane, tris(2-aminoethyl)amine, N,N'-bis(3-aminopropyl)ethylenediamine, polymethylenediamine, trimethylhexamethylenediamine, poly Examples include aliphatic amines such as ether diamines; alicyclic amines such as isophorone diamine, menthane diamine, piperazine, N-aminoethylpiperazine, 3,9-bis(3-aminopropyl)2,4,8,10-tetraoxaspiro(5,5)undecane adduct, bis(4-amino-3-methylcyclohexyl)methane, bis(4-aminocyclohexyl)methane, and modified versions thereof; aliphatic polyamines such as polyethyleneimines and polyalkylene polyamines; (meth)acrylic polymers having amino groups such as aminoethylated acrylic polymers; and aliphatic polyamidoamines formed by the reaction of polyamines with dimer acids. Amine monomers can be used alone or in combination of two or more.

[0080] Examples of epoxy monomers include monofunctional epoxy such as n-butyl glycidyl ether, higher alcohol glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, p-sec-butylphenyl glycidyl ether, and t-butylphenyl glycidyl ether. Examples of compounds include: diepoxyalkanes such as 1,5-hexadiene diepoxide, 1,7-octadiene diepoxide, and 1,9-decadiene diepoxide; polyfunctional epoxy compounds having an ether group, such as (poly)ethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, and sorbitol polyglycidyl ether; and polyfunctional epoxy compounds having an amino group, such as N,N,N',N'-tetraglycidylmetoxylendiamine and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0081] The epoxy monomer may, in some cases, be an aromatic epoxy resin, a non-aromatic epoxy resin, etc. Examples of aromatic epoxy resins include polyphenyl-based epoxy resins, epoxy resins containing fluorene rings, epoxy resins containing triglycidyl isocyanurate, and epoxy resins containing heteroaromatic rings (e.g., triazine rings). Examples of polyphenyl-based epoxy resins include bisphenol A type epoxy resins, brominated bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD ​​type epoxy resins, stilbene type epoxy resins, biphenyl type epoxy resins, bisphenol A novolac type epoxy resins, cresol novolac type epoxy resins, diaminodiphenylmethane type epoxy resins, and tetrakis(hydroxyphenyl)ethane-based epoxy resins. Examples of non-aromatic epoxy resins include aliphatic glycidyl ether type epoxy resins, aliphatic glycidyl ester type epoxy resins, alicyclic glycidyl ether type epoxy resins, alicyclic glycidylamine type epoxy resins, and alicyclic glycidyl ester type epoxy resins.

[0082] Epoxy monomers can be used individually or in combination of two or more. When using monofunctional epoxy compounds, it is preferable to use them in combination with other epoxy monomers containing two or more epoxy groups. Monofunctional epoxy compounds can also be used as reactive diluents to adjust the viscosity of the monomer group for forming reactant P1.

[0083] As described above, polymer P as an amine polymer contains constituent units U1 derived from epoxy monomers. When polymer P is reactant P1, polymer P further contains constituent units U2 derived from amine monomers. The content of constituent units U1 in polymer P, particularly reactant P1, is, for example, 20 wt% to 70 wt%. The content of constituent units U2 in polymer P, particularly reactant P1, is, for example, 30 wt% or more, preferably 50 wt% or more. The upper limit of the content of constituent units U2 is not particularly limited, but is, for example, 80 wt%.

[0084] The glass transition temperature Tg of polymer P is not particularly limited, and is, for example, 40°C or lower, preferably 30°C or lower, more preferably 20°C or lower, even more preferably 15°C or lower, and may be 10°C or lower, 5°C or lower, or 0°C or lower. When the glass transition temperature Tg of polymer P is this low, the adsorbent 11 tends to adsorb acidic gases at a high rate. The lower limit of the glass transition temperature Tg of polymer P is, for example, -100°C, preferably -50°C, and more preferably -10°C, from the viewpoint of ensuring sufficient adsorption of acidic gases in the adsorbent 11 and heat resistance. In this specification, the glass transition temperature Tg is the intermediate glass transition temperature (T) determined in accordance with the provisions of JIS K7121:1987. mg This means that polymer P is a solid. Polymer P is typically a thermosetting resin. Polymer P is solid at, for example, 25°C, preferably in the range of 25°C to 80°C.

[0085] The weight-average molecular weight of polymer P is not particularly limited, but is preferably 500 or more. The weight-average molecular weight of polymer P is 1000 or more, more preferably 10000 or more, and even more preferably 100000 or more. The upper limit of the weight-average molecular weight of polymer P is, for example, 10000000 or less.

[0086] The adsorbent 11 may contain polymer P as its main component, or may be composed substantially of polymer P alone. The adsorbent 11 may also contain other components besides polymer P. Examples of other components include a carrier for supporting polymer P, a reaction accelerator, a plasticizer, a pigment, a dye, an antioxidant, a conductive material, an antistatic agent, an ultraviolet absorber, a flame retardant, and an antioxidant.

[0087] Examples of carriers include fibers and fiber structures containing fibers. Examples of fibers include glass fibers; natural fibers such as wood pulp, cotton, and hemp (e.g., Manila hemp); and chemical fibers (synthetic fibers) such as polyester fibers, rayon, vinylon, acetate fibers, polyvinyl alcohol (PVA) fibers, polyamide fibers, polyolefin fibers, and polyurethane fibers. Examples of fiber structures include woven fabrics, nonwoven fabrics, and paper. A specific example of a fiber structure is glass paper.

[0088] Reaction accelerators are used, for example, when synthesizing polymer P. Examples of reaction accelerators include tertiary amines such as triethylamine and tributylamine; and imidazoles such as 2-phenol-4-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenol-4,5-dihydroxyimidazole. These reaction accelerators can accelerate reactions, for example, to synthesize polymer P.

[0089] The polymer P content R1 in the adsorbent 11 is, for example, 5 wt% or more, and may be 10 wt% or more, 15 wt% or more, 20 wt% or more, 25 wt% or more, 30 wt% or more, or even 35 wt% or more. The higher the polymer P content R1, the more the amount of acidic gas adsorbed by the adsorbent 11 tends to improve. The upper limit of the polymer P content R1 is, for example, 80 wt% or less, and may be 60 wt% or less.

[0090] The polymer P content R1 can be measured, for example, by the following method. First, the adsorbent 11 is placed in a simultaneous thermal analysis DSC / TGA instrument. At this time, the temperature is set to 30°C. Next, using this instrument, the temperature is raised from 30°C to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere and held at that temperature for 40 minutes (Operation 1). According to Operation 1, water contained in the adsorbent 11 can be removed. Next, the temperature is raised from 100°C to 800°C at a heating rate of 10°C / min and held at that temperature for 5 minutes (Operation 2). According to Operation 2, polymer P can be removed from the adsorbent 11. The ratio (100 × (W1-W2) / W1) of the difference between the weight W1(g) of the adsorbent 11 immediately after Operation 1 and the weight W2(g) of the adsorbent 11 immediately after Operation 2 can be considered as the polymer P content R1 in the adsorbent 11.

[0091] (Support) The support, for example, supports the sheet-like main body 10 and is in direct contact with the sheet-like main body 10. The adsorbent 11 (for example, the adsorbent 11A shown in Figure 2) may or may not further include fixing means for fixing the sheet-like main body 10 and the support. Specific examples of fixing means include adhesives, and more specifically, adhesive sheets containing adhesives. In this specification, the term "adhesive" is used to encompass pressure-sensitive adhesives.

[0092] Furthermore, the adsorbent 11 may not have a support and may consist only of a sheet-like main body 10. That is, the adsorbent 11 is made from a self-supporting membrane (single layer membrane) of the sheet-like main body 10. It may be formed.

[0093] The support material is not particularly limited and may include, for example, ceramics such as cordierite, alumina, cordierite-α-alumina, silicon nitride, zircon mullite, scia pyroxene, alumina-silica-magnesia, zircon silicate, sillimanite, magnesium silicate, zircon, feldspar, and aluminosilicate; metals such as aluminum, titanium, copper, stainless steel, Fe-Cr alloy, and Cr-Al-Fe alloy; and silicone resin, polyolefin, polyester, polyurethane, polycarbonate, and polyetheretherketone. Examples of suitable materials include polyphenylene oxide, polyethersulfone, melamine, polyamide, poly(meth)acrylate, polystyrene, poly(meth)acrylonitrile, polyimide, polyfurfural alcohol, phenolfurfuryl alcohol, melamine formaldehyde, resorcinol formaldehyde, cresol formaldehyde, phenol formaldehyde, polyvinyl alcohol dialdehyde, polycyanurate, poly(meth)acrylamide, epoxy resin, agar, agarose, cellulose, and other resins. The support material is preferably excellent in thermal conductivity and durability, and less susceptible to deterioration due to rust formation or hydrolysis when in contact with water.

[0094] The support may or may not have a porous structure. Examples of supports having a porous structure include paper, nonwoven fabric, foam, and mesh. If the support has a porous structure, for example, the polymer P can be placed inside the pores of the support. However, the polymer P does not necessarily have to be located inside the pores of the support. Examples of supports not having a porous structure include non-porous sheets and foils. The support may also be an aluminum sheet, paper, or nonwoven fabric.

[0095] The support may function as a planar heater, and may be a planar thermoelectric heater or a Peltier element.

[0096] If the support is in sheet form, the thickness of the support may be, for example, 1000 μm or less, but may also be 500 μm or less, 300 μm or less, or even 250 μm or less. The lower limit of the support thickness may be, for example, 50 μm or more, or even 100 μm or more.

[0097] [Methods for recovering acidic gases] The acid gas recovery method of this embodiment includes an adsorption step of bringing a raw material gas G1 containing acid gas into contact with an adsorbent 11 to adsorb the acid gas contained in the raw material gas G1 onto the adsorbent 11, and a desorption step of desorbing the adsorbed gas G2 containing acid gas from the adsorbent 11 that has adsorbed the acid gas. The adsorption step is a step corresponding to the adsorption mode described for the recovery system 100. The desorption step is a step corresponding to the desorption mode described for the recovery system 100.

[0098] In this embodiment, during the desorption process, the adsorbent 11 and the first liquid F1 are brought into contact inside the case 12. As described above, the case 12 is designed to bring the adsorbent 11 into contact with the first liquid F1 while containing the adsorbent 11. This recovery method allows for the desorption of acidic gas from the adsorbent 11 through a simple process, that is, by bringing the adsorbent 11 into contact with the first liquid F1 inside the case 12 during the desorption process.

[0099] In this embodiment, it is preferable to bring the adsorbent 11 into contact with the first liquid F1 by immersing it in the first liquid F1 inside the case 12 during the desorption process. With this configuration, it is possible to easily isolate the adsorbent 11 from gas (for example, the raw material gas G1 remaining inside the case 12) and heat the adsorbent 11. Furthermore, it can be expected that this will also have the effect of removing deposits and other substances adhering to the surface of the adsorbent 11.

[0100] In this embodiment, the desorption step includes supplying the first liquid F1 to the case 12 containing the adsorbent 11. With this configuration, by supplying the first liquid F1 to the case 12 in the desorption step, the raw material gas G1 remaining in the case 12 is replaced by the first liquid F1. As a result, the adsorbent 11 can receive thermal energy from the first liquid F1 and desorb the acidic gas.

[0101] In this embodiment, the adsorption process and the desorption process are carried out inside the same case 12. With this configuration, for example, it is easier to switch between the adsorption process and the desorption process compared to a case where the case for the adsorption process and the case for the desorption process are different.

[0102] The recovery method of this embodiment may further include a drainage step between the desorption step and the adsorption step, in which the first liquid F1 (treated water F4) used in the desorption step is discharged to the outside of the case 12. The drainage step allows the treated water F4 to be discharged to the outside of the case 12. The drainage step may also include supplying the treated water F4 to the first liquid supply unit 20.

[0103] Next, the method for recovering acidic gases in this embodiment will be described with reference to the recovery system 100 shown in Figure 1.

[0104] The adsorption process is carried out in the recovery system 100, for example, as follows: First, valves 41 and 43 are opened, and the raw material gas G1 is supplied into the case 12 through the raw material gas supply path 31. At this time, valves 42, 44, and 45 are closed. As a result, the first liquid F1 remaining in the case 12 is replaced with the raw material gas G1. Inside the case 12, for example, the adsorbent 11 after the acidic gas has been desorbed is located. The temperature of the raw material gas G1 supplied to the case 12 is preferably 50°C or lower, 40°C or lower, and even 30°C or lower. The raw material gas G1 is, for example, air.

[0105] The raw material gas G1 supplied to case 12 moves through the ventilation path 14 and comes into contact with the main body 10 (10A and 10B). The main body 10, upon contact with the raw material gas G1, adsorbs the acidic gas contained in the raw material gas G1.

[0106] The raw material gas G1 (non-adsorbent gas G3) processed inside case 12 is discharged from the gas outlet 12c of case 12 and released into the atmosphere, for example, through the non-adsorbent gas discharge path 33.

[0107] Non-adsorbed gas G3 has a lower acidic gas content compared to the desorbed gas (adsorbed gas G2). The acidic gas content in non-adsorbed gas G3 is, for example, 0.1 vol% or more, preferably 1 vol% or more, lower than that of adsorbed gas G2. The acidic gas content in non-adsorbed gas G3 is, for example, 0.003 vol% or more and 10 vol% or less.

[0108] In the recovery method of this embodiment, at the start of the adsorption process, the adsorbent 11 contains moisture (first liquid F1) or moisture is attached to the surface of the adsorbent 11. Using such an adsorbent 11 can improve the rate of adsorption of acidic gases. This is thought to be partly due to the improvement in the internal diffusivity of the adsorbent 11 as its water content increases. Furthermore, if the adsorbent 11 contains moisture (first liquid F1) or moisture is attached to the surface of the adsorbent 11 at the start of the adsorption process, the moisture contained in the adsorbent 11 or attached to the surface of the adsorbent 11 will volatilize upon contact with the raw material gas G1, thus lowering the temperature of the adsorbent 11 by the heat of vaporization. Therefore, the recovery method of this embodiment can reduce cooling energy. Specifically, for example, the cooling process can be omitted. Consequently, acidic gases can be recovered in a simpler process.

[0109] The desorption process is carried out in the recovery system 100, for example, as follows: First, the on-off valve 41 is closed. Next, the on-off valve 44 is opened, and the first liquid F1 is supplied to the case 12 through the first liquid supply path 34. At this time, the on-off valves 45, 43 and / or 42 are open. As a result, the raw material gas G1 remaining in the case 12 is replaced with the first liquid F1, and the raw material gas G1 is discharged from the on-off valves 43 and / or 42. Inside the case 12 is an adsorbent 11 that adsorbs acidic gas. The acidic gas adsorbed by the adsorbent 11 is, for example, carbon dioxide.

[0110] The first liquid F1 supplied to the inside of case 12 moves through the ventilation path 14 of the adsorbent 11 (11A) and comes into contact with the main body 10 (10A and 10B). The main body 10, in contact with the first liquid F1, receives thermal energy from the first liquid F1 and desorbs the acidic gas. This generates an adsorbent gas G2 containing the acidic gas desorbed from the adsorbent 11. The adsorbent gas G2 is discharged from the gas outlet 12b of case 12 and stored, for example, in a tank for recovery of the adsorbent gas G2 via the gas discharge path 32.

[0111] Adsorbed gas G2 has a higher acidic gas content compared to non-adsorbed gas G3. The acidic gas content in adsorbed gas G2 is, for example, greater than 5 vol% and less than or equal to 100 vol%.

[0112] The drainage process in the recovery system 100 is carried out, for example, as follows: First, the shut-off valve 44 is closed. Next, the first liquid F1 (treated water F4) used in the desorption process is discharged to the outside of the case 12 through the drainage path 35. At this time, the shut-off valves 45, 41 and / or 43 are open. The shut-off valve 42 is closed. For example, in the drainage process, the tank 21 of the first liquid supply unit 20 may be installed below the case 12 to drain the treated water F4 by gravity. The treated water F4 may also be drained by supplying air through any shut-off valve other than the shut-off valve 44. A drainage pump may be installed in the drainage path 35 and the treated water F4 may be drained using the drainage pump. The treated water F4 may also be drained by opening the shut-off valve 44 and reversing the operation of the liquid transfer pump 54 installed in the first liquid supply path 34.

[0113] The treated water F4 discharged outside case 12 is supplied to, for example, the first liquid supply unit 20 and recycled as the first liquid F1.

[0114] The above describes an example of the acid gas recovery system and acid gas recovery method of this embodiment using Figures 1 to 3. However, the acid gas recovery system and acid gas recovery method of this embodiment are not limited to the example described above. Below, Figures 4 to 7 describe four modified examples of the acid gas recovery system and acid gas recovery method. In the modified examples 1 to 4 of the recovery system, elements common to the recovery system 100 described above are given the same reference numerals and their descriptions may be omitted.

[0115] (Variation 1) [Recovery System] Figure 4 is a schematic diagram of a modified example 1 of the acid gas recovery system of this embodiment. The recovery system 101 of modified example 1 further includes a raw material gas discharge path 36 that discharges the raw material gas G1 present inside the case 12 to the outside of the case 12. Except for this, the recovery system 101 has the same configuration as the recovery system 100 described above.

[0116] In the recovery system 100 described above, immediately after the adsorption mode ends, the inside of case 12 is filled with raw material gas G1. Therefore, the adsorbed gas G2 obtained immediately after the desorption mode starts contains the acidic gas desorbed from the adsorbent 11 and the raw material remaining inside case 12. The adsorbed gas G2 contains gas G1. That is, in the initial stages of the desorption mode, the content of acidic gas in the adsorbed gas G2 decreases. However, according to the recovery system 101 of the modified example 1, when the desorption mode is being performed, the first liquid F1 can be supplied to the case 12 through the first liquid supply path 34, while the raw material gas G1 remaining inside the case 12 can be discharged to the outside of the case 12 through the raw material gas discharge path 36. That is, the remaining raw material gas G1 can be pushed out of the case 12 by the first liquid F1. Therefore, the decrease in the content of acidic gas in the adsorbed gas G2 in the initial stages of the desorption mode can be suppressed.

[0117] The raw material gas discharge path 36 is connected to the gas outlet 12f of the case 12 and is a path for discharging the raw material gas G1 from the case 12. The raw material gas discharge path 36 may also be connected to a tank (not shown) for recovering the raw material gas G1. The raw material gas discharge path 36 is provided with an on / off valve 46. Although not shown in the illustration, the raw material gas discharge path 36 may further be provided with a flow control valve to adjust the flow rate of the raw material gas G1 flowing through the raw material gas discharge path 36.

[0118] In the example shown in Figure 4, the raw material gas discharge path 36 is connected to a gas outlet 12f located on the upper surface of the rectangular parallelepiped case 12. With this configuration, for example, when performing the desorption mode, it is easy to discharge the raw material gas G1 remaining inside the case 12 to the outside of the case 12. However, the connection position of the raw material gas discharge path 36 is not limited to the example shown in Figure 4.

[0119] [Methods for recovering acidic gases] In the recovery method of modified example 1, the desorption step includes supplying a first liquid F1 to the case 12 containing the adsorbent 11 while simultaneously discharging the raw material gas G1 present inside the case 12 to the outside of the case 12. This suppresses the decrease in the content of acidic gas contained in the adsorbent gas G2 in the initial stages of the desorption step.

[0120] Next, a modified example of the acidic gas recovery method will be described with reference to the recovery system 101 shown in Figure 4.

[0121] The adsorption process is carried out in the same manner as the adsorption process in the recovery system 100 described above, except that the on / off valve 46 is closed during the adsorption process.

[0122] The desorption process is carried out in the recovery system 101, for example, as follows: First, the on-off valve 41 is closed. Next, the on-off valves 44 and 46 are opened, and the first liquid F1 is supplied to the case 12 through the first liquid supply path 34, while the raw material gas G1 remaining in the case 12 is discharged to the outside of the case 12 through the raw material gas discharge path 36. As a result, the raw material gas G1 remaining in the case 12 is replaced with the first liquid F1. The main body 10, which is in contact with the first liquid F1 inside the case 12, receives thermal energy from the first liquid F1 and desorbs the acidic gas. As a result, adsorbed gas G2 containing the acidic gas desorbed from the adsorbent 11 is generated. The adsorbed gas G2 is discharged from the gas outlet 12b of the case 12 and stored in a tank for recovery, for example, through the gas discharge path 32.

[0123] The drainage process is carried out in the same manner as the drainage process in the recovery system 100 described above, except that the on-off valve 46 is closed during the drainage process.

[0124] (Modification 2) [Recovery System] Figure 5 is a schematic diagram of a modified example 2 of the acid gas recovery system of this embodiment. The recovery system 102 of the modified example 2 further includes a cooling water supply path 37 for supplying cooling water F3 to the case 12. Except for this, the recovery system 102 is the same as the recovery system 10 described above. It has the same configuration as 0.

[0125] In the recovery system 100 described above, immediately after the desorption mode is completed, the adsorbent 11 from which the acidic gas has been desorbed has a high temperature due to the influence of the first liquid F1. The temperature of the adsorbent 11 immediately after the desorption mode is, for example, 40°C or higher. If the adsorption mode is performed while the temperature of the adsorbent 11 is high, the adsorbent 11 is prone to deterioration due to oxidation. However, according to the recovery system 102 of the modified example 2, the adsorbent 11 from which the acidic gas has been desorbed can be cooled by supplying cooling water F3 to the case 12 between the execution of the desorption mode and the execution of the adsorption mode. This suppresses deterioration of the adsorbent 11 due to oxidation.

[0126] In this specification, cooling water F3 is a liquid having a temperature of room temperature (25°C) or lower. The upper limit of the temperature of cooling water F3 may be, for example, 20°C or lower, 15°C or lower, or even 10°C or lower. The lower limit of the temperature of cooling water F3 may be, for example, -30°C or higher, -20°C or higher, -10°C or higher, or even 0°C or higher. The same liquids described for the first liquid F1 and the second liquid F2 can be used as cooling water F3. That is, for example, water, a mixture of water and ethylene glycol or propylene glycol can be used as cooling water F3. When cooling water F3 is water, the lower limit of the temperature of cooling water F3 is 0°C or higher. When cooling water F3 is a mixture of water and ethylene glycol or propylene glycol, the lower limit of the temperature of cooling water F3 is -30°C or higher.

[0127] The cooling water supply path 37 is connected to the cooling water inlet 12g of the case 12 and is a path for supplying cooling water F3 to the case 12. The cooling water supply path 37 is connected to, for example, the cooling water supply unit 60. The cooling water supply path 37 may be directly connected to the cooling water supply unit 60, or it may be configured to continuously supply cooling water F3 from the cooling water supply unit 60 to the case 12. An on-off valve 47 is provided in the cooling water supply path 37. Although not shown in the figures, a liquid transfer mechanism may be provided in the cooling water supply unit 60 and / or the cooling water supply path 37. Examples of liquid transfer mechanisms include a liquid transfer pump provided in the cooling water supply path 37, and a mechanism that uses gravity to supply cooling water F3 from the cooling water supply unit 60 to the case 12. A liquid transfer pump may be provided upstream or downstream of the on-off valve 47. For example, a pump for supplying cryogenic fluids can be used as the liquid transfer pump. Although not shown in the diagram, the cooling water supply path 37 may also be provided with a flow control valve to adjust the flow rate of the cooling water F3 flowing through the cooling water supply path 37.

[0128] In the example shown in Figure 5, the cooling water supply path 37 is connected to a cooling water inlet 12g located on the side of the rectangular parallelepiped case 12. With this configuration, for example, in a cooling mode for cooling an adsorbent 11 from which an acidic gas has been desorbed, cooling water F3 can be supplied evenly to the adsorbent 11 housed in the case 12. However, the connection position of the cooling water supply path 37 is not limited to the example shown in Figure 5.

[0129] The configuration of the cooling water supply unit 60 is not particularly limited, as long as it can supply cooling water F3 to the case 12. As shown in Figure 5, the cooling water supply unit 60 may include a tank 61 for storing cooling water F3. The tank 61 may also include a chiller (not shown). By supplying cooling water F3 to the case 12 from the cooling water supply unit 60, the adsorbent 11 from which the acidic gas has been desorbed can be cooled between the execution of the desorption mode and the execution of the adsorption mode.

[0130] In the recovery system 102 shown in Figure 5, the drainage path 35 branches into a first section 35a and a second section 35b at the downstream branching point 35p. The first section 35a is connected to, for example, the first liquid supply unit 20. The second section 35b is connected to, for example, the cooling water supply unit 60. The second section 35b may also be directly connected to the cooling water supply unit 60, and from case 12 The cooling water supply unit 60 may be configured to continuously supply treated water F4. With such a configuration, for example, if the cooling water F3 is the same liquid as the first liquid F1, the treated water F4 from the first liquid F1 and the cooling water F3 can be recovered and recycled together.

[0131] A three-way valve 45p is provided at the branching point 35p. However, the recovery system 102 may instead be equipped with an on-off valve provided in the first section 35a and an on-off valve provided in the second section 35b. Although not shown in the figures, the first section 35a may further be equipped with a flow control valve to adjust the flow rate of the treated water F4 flowing through the first section 35a. Although not shown in the figures, the second section 35b may further be equipped with a flow control valve to adjust the flow rate of the treated water F4 flowing through the second section 35b.

[0132] [Methods for recovering acidic gases] The recovery method of the modified example 2 further includes a cooling step for cooling the adsorbent 11 from which the acidic gas has been desorbed. By performing a cooling step between the desorption step and the adsorption step, the adsorbent 11 from which the acidic gas has been desorbed can be cooled. This suppresses deterioration of the adsorbent 11 due to oxidation.

[0133] In the recovery method of modified example 2, the adsorption step, desorption step, and cooling step may be repeated in this order.

[0134] In the recovery method of Modified Example 2, it is preferable to perform a drainage step between the desorption step and the cooling step. The cooling step may be performed in parallel with the drainage step. With this configuration, for example, the first liquid F1 (treated water F4) used in the desorption step can be discharged to the outside of the case 12 while cooling water F3 can be supplied to the case 12. This reduces the energy required in the cooling step.

[0135] Next, a modified example of the acidic gas recovery method will be described with reference to the recovery system 102 shown in Figure 5.

[0136] The adsorption process is carried out in the same manner as the adsorption process in the recovery system 100 described above. However, during the adsorption process, the on-off valve 47 and the three-way valve 45p are closed.

[0137] The detachment process is carried out in the same manner as the detachment process in the recovery system 100 described above, except that the on-off valve 47 is closed during the detachment process.

[0138] The wastewater treatment process is carried out in the same manner as the wastewater treatment process in the recovery system 100 described above.

[0139] A cooling process may be carried out in parallel with the drainage process. That is, the first liquid F1 (treated water F4) used in the desorption process may be discharged to the outside of the case 12 while cooling water F3 is supplied to the case 12. In this case, the cooling process is carried out in the recovery system 102 as follows, for example. First, the on-off valve 47 is opened and cooling water F3 is supplied to the case 12 through the cooling water supply path 37. At this time, the three-way valve 45p, on-off valve 41 and / or on-off valve 43 are open. On-off valve 42 is closed. As a result, for example, the first liquid F1 remaining in the case 12 is replaced with cooling water F3.

[0140] (Variation 3) [Recovery System] Figure 6 is a schematic diagram of a modified example 3 of the acid gas recovery system of this embodiment. The recovery system 103 of modified example 3 has a second liquid supply path 38 that supplies the second liquid F2 to the case 12. The system further includes a heating unit 23 that heats the second liquid F2 supplied to the case 12 to produce the first liquid F1. Except for the inclusion of a second liquid supply path 38 and a heating unit 23 in place of the first liquid supply path 34, the recovery system 103 has the same configuration as the recovery system 101 of the modified example 1 described above.

[0141] According to the recovery system 103 of the modified example 3, when the desorption mode is performed, the second liquid F2 can be supplied to the case 12 through the second liquid supply path 38, while the raw material gas G1 remaining inside the case 12 can be discharged to the outside of the case 12 through the raw material gas discharge path 36. In other words, the remaining raw material gas G1 can be pushed out of the case 12 by the second liquid F2. This suppresses the decrease in the content of acidic gas contained in the adsorbed gas G2 in the initial stages of the desorption mode. Furthermore, the first liquid F1 can be generated by heating the second liquid F2 supplied to the case 12 in the heating section 23. As a result, the adsorbent 11 can receive thermal energy from the first liquid F1 and desorb the acidic gas.

[0142] The second liquid supply path 38 is connected to the second liquid inlet 12h of the case 12 and is a path for supplying the second liquid F2 to the case 12. The second liquid supply path 38 is connected to, for example, the second liquid supply unit 70. The second liquid supply path 38 may be directly connected to the second liquid supply unit 70, or it may be configured to continuously supply the second liquid F2 from the second liquid supply unit 70 to the case 12. An on-off valve 48 is provided in the second liquid supply path 38. A liquid supply mechanism may be provided in the second liquid supply unit 70 and / or the second liquid supply path 38. Examples of liquid supply mechanisms include a liquid supply pump provided in the second liquid supply path 38, and a mechanism that supplies the second liquid F2 from the second liquid supply unit 70 to the case 12 using gravity. In the example shown in Figure 6, a liquid supply pump 58 is provided upstream of the on-off valve 48. For example, a pump for supplying cryogenic fluids can be used as the liquid supply pump 58. Although not shown in the diagram, the second liquid supply path 38 may also be provided with a flow control valve to adjust the flow rate of the second liquid F2 flowing through the second liquid supply path 38.

[0143] In the example shown in Figure 6, the second liquid supply path 38 is connected to a second liquid inlet 12h provided on the side of the rectangular parallelepiped case 12. With this configuration, for example, in the desorption mode, the second liquid F2 can be supplied evenly to the adsorbent 11 housed in the case 12. However, the connection position of the second liquid supply path 38 is not limited to the example shown in Figure 6.

[0144] The configuration of the second liquid supply unit 70 is not particularly limited, as long as it can supply the second liquid F2 to the case 12. As shown in Figure 6, the second liquid supply unit 70 may include a tank 71 for storing the second liquid F2. The tank 71 may also include a chiller (not shown). By supplying the second liquid F2 from the second liquid supply unit 70 to the case 12, for example, the raw material gas G1 remaining inside the case 12 can be discharged to the outside of the case 12.

[0145] The configuration of the heating unit 23 is not particularly limited, as long as it can heat the second liquid F2 supplied to the case 12 to produce the first liquid F1. The heating unit 23 may be located inside the case 12 and directly heat the second liquid F2, or it may be located outside the case 12 and indirectly heat the second liquid F2. Typically, the heating unit 23 is a heater located inside the case 12.

[0146] [Methods for recovering acidic gases] In the recovery method of modified example 3, the desorption step includes supplying a second liquid F2 to a case 12 containing the adsorbent 11 and heating the second liquid F2 supplied to the case 12. As a result, the adsorbent 11 can receive thermal energy from the first liquid F1 generated by the heating and desorb the acidic gas.

[0147] In the recovery method of modified example 3, during the desorption process, the raw material gas G1 present inside the case 12 may be discharged to the outside of the case 12 while the second liquid F2 is supplied to the case 12. This makes it possible to suppress the decrease in the content of acidic gas contained in the adsorbed gas G2 in the initial stages of the desorption process.

[0148] Next, a modified example 3 of the acidic gas recovery method will be described with reference to the recovery system 103 shown in Figure 6.

[0149] The adsorption process is carried out in the same manner as the adsorption process in the recovery system 100 described above, except that the on / off valve 48 is closed during the adsorption process.

[0150] The desorption process is carried out in the recovery system 103, for example, as follows: First, the on-off valves 41 and 43 are closed. Next, the on-off valves 48 and 46 are opened, and the second liquid F2 is supplied to the case 12 through the second liquid supply path 38, while the raw material gas G1 remaining in the case 12 is discharged to the outside of the case 12 through the raw material gas discharge path 36. As a result, the raw material gas G1 remaining in the case 12 is replaced by the second liquid F2. Once the inside of the case 12 is filled with the second liquid F2, the heating unit 23 heats the second liquid F2 to generate the first liquid F1. The main body 10, which is in contact with the first liquid F1 inside the case 12, receives thermal energy from the first liquid F1 and desorbs the acidic gas. As a result, adsorbed gas G2 containing the acidic gas desorbed from the adsorbent 11 is generated.

[0151] The drainage process is carried out in the same manner as the drainage process in the recovery system 100 described above, except that the on-off valve 46 is closed during the drainage process.

[0152] (Modification 4) [Recovery System] Figure 7 is a schematic diagram of a modified example 4 of the acid gas recovery system of this embodiment. In the recovery system 104 of modified example 4, the adsorption mode is performed outside the case 12. Except for this, the recovery system 104 has generally the same configuration as the recovery system 100 described above.

[0153] In the example shown in Figure 7, the recovery system 104 further includes a pre-case 12p for containing the adsorbent 11 and a transfer mechanism (not shown) for moving the adsorbent 11, which has adsorbed the acidic gas, into the case 12 during the adsorption mode. That is, in the recovery system 104, the case for performing the adsorption mode and the case for performing the desorption mode are different. However, as long as the adsorption mode is performed outside the case 12, the configuration of the recovery system 104 is not limited to the example shown in Figure 7. For example, in the adsorption mode, the adsorbent 11 removed from the case 12 may be exposed to the atmosphere, causing the adsorbent 11 to come into direct contact with the atmosphere. In the adsorption mode, a blowing mechanism such as a fan may be used to bring the raw material gas G1 into contact with the adsorbent 11 removed from the case 12.

[0154] The recovery system 104 allows for case designs tailored to each mode. For example, the recovery system 104 allows the first liquid F1 used in case 12 to be reused repeatedly inside case 12 without being discarded. This reduces the energy required to generate the first liquid F1.

[0155] The configuration of the moving mechanism is not particularly limited, as long as the adsorbent material 11 can be moved from the pre-case 12p to the case 12. For example, a crane can be used as the moving mechanism to move the adsorbent material 11 up and down.

[0156] The shape of case 12 and the shape of pre-case 12p may be the same or different. good.

[0157] In the recovery system 104 of the modified example 4, the pre-case 12p is a case for performing the adsorption mode. As shown in Figure 7, the pre-case 12p is connected to a raw material gas supply path 31 and a non-adsorbed gas discharge path 33. The non-adsorbed gas discharge path 33 is connected to the gas outlet 12c of the pre-case 12p and is a path for discharging non-adsorbed gas G3 from the pre-case 12p. An on-off valve 43 is provided in the non-adsorbed gas discharge path 33.

[0158] In the recovery system 104 of the modified example 4, case 12 is a case for performing the desorption mode. As shown in Figure 7, a first liquid supply path 34 and an adsorption gas discharge path 32 are connected to case 12. The adsorption gas discharge path 32 is connected to the gas outlet 12b of case 12 and is a path for discharging the adsorption gas G2 from case 12. An on / off valve 42 is provided in the adsorption gas discharge path 32.

[0159] As shown in Figure 7, the case 12 may also be further connected to a drainage path 35 for discharging the first liquid F1 (treated water F4) used in the desorption mode to the outside of the case 12.

[0160] As shown in Figure 7, the case 12 may include a heating unit 24 for heating the first liquid F1 supplied to the case 12 and maintaining the temperature of the first liquid F1. The configuration of the heating unit 24 is not particularly limited. The heating unit 24 may be located inside the case 12 and directly heat the first liquid F1, or it may be located outside the case 12 and indirectly heat the first liquid F1. Typically, the heating unit 24 is a heater located inside the case 12.

[0161] [Methods for recovering acidic gases] In the recovery method of Modified Example 1, the adsorption process is carried out outside the case 12, and a containment process is further included between the adsorption process and the desorption process, in which the adsorbent 11 that has adsorbed the acidic gas is contained inside the case 12. This allows for case design tailored to each process. In the recovery method of Modified Example 1, for example, by performing the adsorption process at multiple locations and the desorption process at one location, the equipment and costs associated with the desorption process can be consolidated into one location.

[0162] In the recovery method of Modification 1, the adsorption process is performed outside of case 12.

[0163] Next, a modified example 4 method for recovering acidic gas will be described with reference to the recovery system 104 shown in Figure 7.

[0164] The adsorption process is carried out in the same manner as the adsorption process in the recovery system 100 described above. However, the adsorption process is carried out in the pre-case 12p.

[0165] A containment process is performed between the adsorption process and the desorption process. In the containment process, for example, the adsorbent 11 is moved from the pre-case 12p to the case 12 by a moving mechanism.

[0166] The containment process is carried out in the recovery system 104, for example, as follows: After the adsorption process is completed, the adsorbent 11 that has adsorbed the acidic gas is moved from the pre-case 12p into the inside of the case 12. This movement can be carried out, for example, using a moving mechanism.

[0167] The detachment process is carried out in the same manner as the detachment process in the recovery system 100 described above. However, the detachment process is performed in case 12.

[0168] In the acid gas recovery method of Modification 4, the first liquid F1 inside the case 12 can be reused repeatedly without performing a wastewater treatment process.

[0169] The descriptions of each embodiment and each modification described above are interchangeable, insofar as they do not conflict with technical standards. Furthermore, each embodiment and each modification may be combined with each other, insofar as they do not conflict with technical standards. [Industrial applicability]

[0170] The acid gas recovery method and recovery system of this embodiment are suitable for recovering acid gases, particularly carbon dioxide. [Explanation of Symbols]

[0171] 100, 101, 102, 103, 104 Recovery System 11, 11A, 11B Adsorbent 10, 10A, 10B Main Unit 13a Yamabe 13b Tanibe 14. Ventilation paths 15 units 12 cases 12p Pre-case 20 1st liquid supply section 23, 24 Heating section 31. Raw material gas supply route 31a Intake 31b Air blower mechanism 32 Adsorbed gas discharge path 33 Non-adsorbed gas emission pathway 34. First liquid supply route 35 Drainage routes 36. Raw material gas emission routes 37 Cooling water supply route 38. Second liquid supply route 41, 42, 43, 44, 45, 46, 47, 48 Shut-off valves 45p Three-way valve 50 Controllers 54, 58 Liquid transfer pump 60 Cooling water supply section 70 Second liquid supply section G1 raw material gas G2 Adsorbent Gas G3 Non-adsorbent gas F1 1st liquid F2 2nd liquid F3 cooling water F4 treated water

Claims

1. An adsorption step in which a raw material gas containing an acidic gas is brought into contact with an adsorbent, and the acidic gas contained in the raw material gas is adsorbed onto the adsorbent, The process includes a desorption step of desorbing the adsorbed gas containing the acidic gas from the adsorbent material that has adsorbed the acidic gas, A method for recovering acidic gas, wherein in the desorption step, the adsorbent is housed in a case and brought into contact with a first liquid having a temperature higher than room temperature.

2. The method for recovering an acidic gas according to claim 1, wherein in the desorption step, the adsorbent is brought into contact with the first liquid by immersing the adsorbent in the first liquid inside the case.

3. The method for recovering acidic gas according to claim 1, wherein the desorption step includes supplying the first liquid to the case containing the adsorbent.

4. The adsorption process is carried out inside the case. The method for recovering an acidic gas according to claim 1, wherein the desorption step includes supplying the first liquid to the case containing the adsorbent while discharging the raw material gas present inside the case to the outside of the case.

5. The method for recovering an acidic gas according to claim 1, wherein the desorption step includes supplying a second liquid having a temperature below room temperature to the case containing the adsorbent, and heating the second liquid supplied to the case.

6. The method for recovering an acidic gas according to claim 1, further comprising a cooling step of cooling the adsorbent from which the acidic gas has been desorbed.

7. The method for recovering an acidic gas according to claim 1, wherein the adsorption step and the desorption step are carried out inside the same case.

8. The adsorption process is carried out outside the case. The method for recovering an acidic gas according to claim 1, further comprising a containment step between the adsorption step and the desorption step, in which the adsorbent material that has adsorbed the acidic gas is contained inside the case.

9. The method for recovering acidic gas according to claim 1, wherein the adsorbent comprises a polymer having an amino group.

10. The method for recovering acidic gas according to claim 9, wherein the polymer has constituent units derived from an epoxy compound and constituent units derived from an amine compound.

11. The method for recovering an acidic gas according to claim 1, wherein the temperature of the first liquid is 40°C or higher.

12. An acid gas recovery system comprising: an adsorbent that, while adsorbing an acid gas, comes into contact with a first liquid having a temperature higher than room temperature to desorb the acid gas; and a case that houses the adsorbent and brings the adsorbent into contact with the first liquid.

13. The acid gas recovery system according to claim 12, further comprising a first liquid supply path for supplying the first liquid to the case.

14. A raw material gas supply path for supplying the raw material gas containing the acidic gas to the aforementioned case, The acid gas recovery system according to claim 12, further comprising a raw material gas discharge path for discharging the raw material gas present inside the case to the outside of the case.

15. The acid gas recovery system according to claim 12, further comprising: a second liquid supply path for supplying a second liquid having a temperature below room temperature to the case; and a heating unit for heating the second liquid supplied to the case to produce the first liquid.

16. The acid gas recovery system according to claim 12, further comprising a cooling water supply path for supplying cooling water to the case.

17. A pre-case for housing the adsorbent material when performing the adsorption mode in which the acidic gas is adsorbed onto the adsorbent material, The acid gas recovery system according to claim 12, further comprising a moving mechanism for moving the adsorbent material that adsorbs the acid gas into the interior of the case.

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