Gas treatment apparatus, gas treatment method, carbon dioxide recovery system, and carbon dioxide recovery method

Abstract

To provide a gas treatment apparatus, a gas treatment method, a carbon dioxide recovery system, and a carbon dioxide recovery method capable of satisfactorily maintaining the performance of a treatment agent such as an absorption solvent.SOLUTION: According to one embodiment, a gas treatment device includes an oxygen separator that separates oxygen gas contained in exhaust gas and discharges a first gas containing the exhaust gas separated from the oxygen gas. The apparatus further includes a gas treatment device that treats the first gas with a treatment agent and discharges a second gas containing the first gas treated with the treatment agent. The oxygen separator includes a composite membrane containing a first material that is an organic substance and a second material that is an inorganic substance or an organic substance, and separates the oxygen gas from the exhaust gas by supplying the exhaust gas to the composite membrane.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to a gas treatment device, a gas treatment method, a carbon dioxide capture system, and a carbon dioxide capture method. [Background technology]

[0002] Carbon dioxide capture and storage (CCS) technology is attracting attention as an effective measure against global warming. For example, the installation of CCS facilities in facilities that generate large amounts of carbon dioxide gas (such as thermal power plants, steel mills, and cement factories) is being considered around the world.

[0003] One example of CCS technology is the chemical absorption method, which separates and captures carbon dioxide by contacting exhaust gas containing carbon dioxide with an absorption solvent. Examples of absorption solvents used in the chemical absorption method include silicone oil, amine-based solutions, and ionic solutions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4274846 Summary of the Invention [Problem to be solved by the invention]

[0005] The components contained in exhaust gas vary depending on the facility that emits the exhaust gas and the raw materials that generate it. However, most types of exhaust gas commonly contain nitrogen (N2) gas and oxygen (O2) gas as components other than carbon dioxide gas.

[0006] When flue gas containing oxygen gas is introduced into a CCS facility, not only carbon dioxide gas but also oxygen gas is absorbed by the absorption solvent. When oxygen gas is absorbed by the absorption solvent, an oxygen gas absorption reaction occurs in the absorption solvent, which may cause the absorption solvent to oxidize (decompose). Oxidation of the absorption solvent reduces the component concentration of the absorption solvent and may reduce the absorption performance of the absorption solvent for carbon dioxide gas. As a result, it may not be possible to separate and recover carbon dioxide gas from the flue gas in the desired state.

[0007] Furthermore, if oxygen gas is entrained in the carbon dioxide gas after the carbon dioxide gas and oxygen gas have been stripped from the absorption solvent, the oxygen will be mixed into the carbon dioxide gas that is finally recovered as a product, resulting in a decrease in the purity of the carbon dioxide and a decrease in the quality of the carbon dioxide.

[0008] Therefore, embodiments of the present invention provide a gas treatment device, a gas treatment method, a carbon dioxide recovery system, and a carbon dioxide recovery method that can maintain the performance of a treatment agent such as an absorption solvent at a good level. [Means for solving the problem]

[0009] According to one embodiment, a gas treatment device includes an oxygen separator that separates oxygen gas contained in an exhaust gas and discharges a first gas containing the exhaust gas from which the oxygen gas has been separated. The device further includes a gas treatment device that treats the first gas with a treatment agent and discharges a second gas containing the first gas treated with the treatment agent. The oxygen separator includes a composite membrane containing a first material that is an organic substance and a second material that is an inorganic or organic substance, and separates the oxygen gas from the exhaust gas by supplying the exhaust gas to the composite membrane. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing the configuration of a carbon dioxide capture system 101 of a first embodiment. [Figure 2] 1 is a schematic diagram partially illustrating the configuration of a carbon dioxide capture system 101 according to a first embodiment. [Figure 3] FIG. 10 is a schematic diagram partially illustrating the configuration of a carbon dioxide capture system 102 according to a second embodiment. [Figure 4] FIG. 10 is a schematic diagram partially illustrating the configuration of a carbon dioxide capture system 103 according to a third embodiment. [Figure 5] FIG. 10 is a schematic diagram partially illustrating the configuration of a carbon dioxide capture system 104 according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In Figures 1 to 5, the same components are denoted by the same reference numerals, and redundant description will be omitted.

[0012] (First embodiment) 1 is a schematic diagram showing the configuration of a carbon dioxide capture system 101 according to a first embodiment. The carbon dioxide capture system 101 is an example of a gas treatment device.

[0013] The carbon dioxide recovery system 101 includes an exhaust gas line 1, an oxygen separator 2, an absorber 3, a rich liquid transfer pump 4, a regenerative heat exchanger 5, a regenerator 6, a reboiler 7, a lean liquid transfer pump 8, a lean liquid cooler 9, an absorber outlet cooler 11, an absorber outlet separator 12, a regenerator outlet cooler 13, a regenerator outlet separator 14, a condensed water transfer pump 15, and a control unit 21. The absorber 3 is an example of a gas processor. The oxygen separator 2 includes a separation unit 2a, a liquid reservoir unit 2b, and one or more composite membranes 2c. The absorber 3 includes a packed bed 3a and a liquid reservoir unit 3b. The regenerator 6 includes a packed bed 6a and a liquid reservoir unit 6b.

[0014] The exhaust gas line 1 is a flow path that introduces exhaust gas discharged from an exhaust gas discharge facility (not shown) into the absorber 3 via an oxygen separator 2. The symbol G1 represents exhaust gas flowing from the exhaust gas discharge facility into the oxygen separator 2. In this embodiment, the exhaust gas G1 flows from the exhaust gas discharge facility into the oxygen separator 2 in a pressurized state without being depressurized. The exhaust gas discharge facility is, for example, a power plant such as a coal-fired power plant, a factory such as a steel mill or a waste incineration plant, or a combustion facility such as a waste incineration plant or manufacturing facility. The exhaust gas G1 is, for example, combustion exhaust gas.

[0015] The oxygen separator 2 separates the oxygen gas contained in the flue gas G1 and discharges a gas G2 containing the oxygen gas separated from the flue gas G1, and a gas G3 containing the flue gas G1 from which the oxygen gas has been separated. The oxygen separator 2 has an inlet for introducing the flue gas G1 into the oxygen separator 2, an outlet for discharging the gas G2 from the oxygen separator 2, and an outlet for discharging the gas G3 from the oxygen separator 2. The gas G3 discharged from the oxygen separator 2 is transferred to the absorber 3 via the flue gas line 1.

[0016] Gas G2 is an oxygen-rich gas that is rich in oxygen gas and that is separated from exhaust gas G1. Hereinafter, gas G2 will also be referred to as "oxygen-rich gas G2." On the other hand, gas G3 is a treated exhaust gas that contains exhaust gas G1 from which oxygen gas has been separated. Gas G3 may further contain oxygen gas that remained in exhaust gas G1 without being separated from exhaust gas G1. Hereinafter, gas G3 will also be referred to as "treated exhaust gas G3" or "exhaust gas G3." Exhaust gas G3 is an example of the first gas.

[0017] The oxygen separator 2 of this embodiment reduces the oxygen concentration of the exhaust gas G3 discharged from the oxygen separator 2 to a value lower than the oxygen concentration of the exhaust gas G1 introduced into the oxygen separator 2. The reason for this is that the oxygen concentration of the exhaust gas G1 decreases in the oxygen separator 2 as oxygen gas is separated from the exhaust gas G1. However, the oxygen concentration of the exhaust gas G3 may be higher than the oxygen concentration of the exhaust gas G1 in some cases. For example, when oxygen gas and other gases are separated from the exhaust gas G1, or when the pressure and temperature of the exhaust gas G3 are different from those of the exhaust gas G1, the oxygen concentration of the exhaust gas G3 may be higher than the oxygen concentration of the exhaust gas G1.

[0018] The separation section 2a is disposed within the oxygen separator 2. The exhaust gas G1 of this embodiment is separated from oxygen gas when it passes through the separation section 2a. The liquid reservoir section 2b is provided below the separation section 2a within the oxygen separator 2. Liquid introduced into the oxygen separator 2 and liquid generated within the oxygen separator 2 flow down to the liquid reservoir section 2b and accumulates in the liquid reservoir section 2b. The composite membrane 2c is disposed within the separation section 2a within the oxygen separator 2. The exhaust gas G1 of this embodiment is separated from oxygen gas when it passes through the composite membrane 2c within the separation section 2a. Further details of the oxygen separator 2 will be described later.

[0019] The absorber 3 treats the flue gas G3 with an absorption solvent. Symbol S1 represents the absorption solvent (lean solvent) flowing into the absorber 3. The absorber 3 brings the flue gas G3 and the absorption solvent S1 into gas-liquid contact, causing the carbon dioxide contained in the flue gas G3 to be absorbed by the absorption solvent S1. As a result, carbon dioxide is removed from the flue gas G3. Symbol S2 represents the absorption solvent (rich solvent) that has absorbed carbon dioxide. The absorption solvent S1 absorbs carbon dioxide from the flue gas G3 and changes into the absorption solvent S2. The absorption solvents S1 and S2 are examples of treatment agents. The absorber 3 has an inlet for introducing the absorption solvent S1 into the absorber 3, an outlet for discharging the absorption solvent S2 from the absorber 3, an inlet for introducing the flue gas G3 into the absorber 3, and an outlet for discharging the absorber exhaust gas containing the flue gas G3 from which carbon dioxide has been removed from the absorber 3. The absorber exhaust gas may further contain carbon dioxide that was not removed from the flue gas G3 and remained in the flue gas G3. The absorber effluent gas is an example of a second gas.

[0020] The absorber 3 of this embodiment is a packed-bed countercurrent gas-liquid contactor, and includes a packed bed 3a disposed within the absorber 3 and a liquid reservoir 3b disposed below the packed bed 3a within the absorber 3. The absorber 3 of this embodiment has an inlet for the absorption solvent S1 and an outlet for the absorber discharge gas above the packed bed 3a, and an outlet for the absorption solvent S2 and an inlet for the flue gas G3 below the packed bed 3a. The absorber 3 brings the flue gas G3 rising from the latter inlet and the absorption solvent S1 falling from the former inlet into gas-liquid contact within the packed bed 3a. As a result, the absorber discharge gas obtained from the flue gas G3 is discharged (released) to the outside of the absorber 3 from the former outlet, and the absorption solvent S2 converted from the absorption solvent S1 accumulates in the liquid reservoir 3b. The absorption solvent S2 accumulated in the liquid reservoir 3b is discharged (released) to the outside of the absorber 3 from the latter outlet. The absorber 3 may be of a type other than the packed bed type, such as a tray type or a wet scrubber type.

[0021] The absorption solvent of this embodiment is a carbon dioxide absorption solvent capable of absorbing carbon dioxide, such as an amine-based solvent, silicone oil, or ionic liquid. The absorption solvent of this embodiment may further contain additives depending on the purpose. The amine-based solvent may contain only one type of amine, or may contain two or more types of amines. Examples of these amines include monoethanolamine and diethanolamine.

[0022] The absorption solvent S1 is a lean solvent that contains a low concentration of carbon dioxide or no carbon dioxide. On the other hand, the absorption solvent S2 is a rich solvent that contains a high concentration of carbon dioxide. Therefore, the carbon dioxide concentration of the absorption solvent S2 is higher than that of the absorption solvent S1. If the absorption solvent S1 does not contain carbon dioxide, the carbon dioxide concentration of the absorption solvent S1 is zero.

[0023] The absorber outlet cooler 11 cools the absorber discharge gas flowing in from the absorber 3 and condenses the water vapor contained in the absorber discharge gas. The condensed water obtained by condensing the water vapor is transferred to the absorber outlet separator 12 together with the absorber discharge gas.

[0024] The absorber outlet separator 12 separates the absorber discharge gas and condensed water that flow in from the absorber outlet cooler 11. The condensed water separated from the absorber discharge gas is returned to the absorber 3 to be mixed with the absorption solvent S1. Meanwhile, the absorber discharge gas separated from the condensed water is released into the atmosphere from the absorber outlet separator 12. At this time, the absorber discharge gas may be washed with a washing liquid (e.g., water) before being released into the atmosphere. This makes it possible to wash and remove the absorption solvent component from the absorber discharge gas. The washing liquid may be the above-mentioned condensed water. The washing liquid after washing the absorber discharge gas may be returned to the absorber 3.

[0025] The carbon dioxide capture system 101 does not necessarily have to include the absorber outlet cooler 11 and the absorber outlet separator 12. In this case, the absorber exhaust gas is released from the absorber 3 into the atmosphere.

[0026] The rich liquid transfer pump 4 transfers the absorption solvent S2 discharged from the absorber 3 to the regenerator 6 via the regenerative heat exchanger 5. At this time, the regenerative heat exchanger 5 exchanges heat between the absorption solvent S2 transferred from the absorber 3 to the regenerator 6 and the absorption solvent S1 transferred from the regenerator 6 to the absorber 3. As a result, the absorption solvent S2 is heated in the regenerative heat exchanger 5.

[0027] The regenerator 6 heats the absorption solvent (rich solvent) S2 flowing in from the absorber 3, causing carbon dioxide gas and water vapor to strip from the absorption solvent S2. The absorption solvent S2 is converted into the absorption solvent (lean solvent) S1 by stripping the carbon dioxide gas and water vapor. In this way, the absorption solvent S2 is regenerated into the absorption solvent S1. The regenerator 6 has an inlet for introducing the absorption solvent S2 into the regenerator 6, an outlet for discharging the absorption solvent S1 from the regenerator 6, an inlet for introducing gas from the reboiler 7 into the regenerator 6, and an outlet for discharging the regenerator exhaust gas containing the carbon dioxide gas and water vapor stripped from the absorption solvent S2 from the regenerator 6. The regenerator exhaust gas is an example of a third gas.

[0028] The regenerator 6 of this embodiment is a packed-bed type countercurrent gas-liquid contactor, and includes a packed bed 6a disposed within the regenerator 6 and a liquid reservoir 6b disposed below the packed bed 6a within the regenerator 6. The regenerator 6 of this embodiment has an inlet for the absorption solvent S2 and an outlet for the regenerator exhaust gas above the packed bed 6a, and an outlet for the absorption solvent S1 and an inlet for the gas from the reboiler 7 below the packed bed 6a. The regenerator 6 brings the gas from the reboiler 7, which rises from the latter inlet, into gas-liquid contact with the absorption solvent S2, which falls from the former inlet, within the packed bed 6a. As a result, the gas from the reboiler 7 heats the absorption solvent S2, and the absorption solvent S2 releases carbon dioxide gas and water vapor. The regenerator discharge gas containing the evaporated carbon dioxide gas and water vapor is discharged (released) from the former outlet to the outside of the regenerator 6, and the absorbing solvent S1 converted from the absorbing solvent S2 accumulates in the liquid reservoir 6b. The absorbing solvent S1 accumulated in the liquid reservoir 6b is discharged (released) from the latter outlet to the outside of the regenerator 6.

[0029] The reboiler 7 is supplied with a portion of the absorption solvent S1 discharged from the regenerator 6. The reboiler 7 heats the supplied absorption solvent S1 to generate carbon dioxide gas and water vapor from the absorption solvent S1. The carbon dioxide gas and water vapor generated from the absorption solvent S1 are returned into the regenerator 6 from the inlet described above as the "gas from the reboiler 7." At this time, the absorption solvent S1 supplied to the reboiler 7 is also returned into the regenerator 6 from this inlet.

[0030] The regenerator 6 may be of a type other than the packed bed type. For example, the regenerator 6 may be of a flash drum type (flash tank type) in which the absorption solvent S2 is heated in a tank to cause carbon dioxide gas and water vapor to dissipate from the absorption solvent S2. In this case, the carbon dioxide recovery system 101 may be provided with an electric heater instead of the reboiler 7 as a heating unit that heats the absorption solvent S2.

[0031] The regenerator outlet cooler 13 cools the regenerator exhaust gas flowing in from the regenerator 6 and condenses the water vapor contained in the regenerator exhaust gas. The condensed water obtained by condensing the water vapor is transferred to the regenerator outlet separator 14 together with the regenerator exhaust gas. The regenerator exhaust gas discharged from the regenerator outlet cooler 13 contains mostly only carbon dioxide and contains absorption solvent components as impurities.

[0032] The regenerator outlet separator 14 separates the regenerator exhaust gas and condensed water that flow in from the regenerator outlet cooler 13. The condensed water separated from the regenerator exhaust gas is returned to the regenerator 6 by the condensed water transfer pump 15 to be mixed with the absorption solvent S2. Meanwhile, the regenerator exhaust gas separated from the condensed water is discharged from the regenerator outlet separator 14 as carbon dioxide captured by the carbon dioxide capture system 101. The regenerator exhaust gas of this embodiment is washed with a cleaning liquid (e.g., water) and then discharged from the regenerator outlet separator 14. This makes it possible to wash and remove impurities such as absorption solvent components from the regenerator exhaust gas. The cleaning liquid may be the above-mentioned condensed water. The cleaning liquid after washing the regenerator exhaust gas may be returned to the regenerator 6 by the condensed water transfer pump 15.

[0033] In this embodiment, the regenerator exhaust gas is discharged from the regenerator outlet separator 14 as high-purity carbon dioxide gas from which impurities have been removed by washing. In this embodiment, the state of the carbon dioxide discharged from the regenerator outlet separator 14 may be transitioned from a gaseous state to a state appropriate for the purpose, such as a supercritical state or a liquid state. This makes it possible to make the state of the carbon dioxide suitable for storage or transportation. The state transition can be caused, for example, by a compression pump. The carbon dioxide after the state transition may be stored or transported, for example, by a tank, a truck, a pipeline, or the like.

[0034] The lean liquid transfer pump 8 transfers the absorption solvent S1 discharged from the regenerator 6 to the absorber 3 via the regenerative heat exchanger 5 and the lean liquid cooler 9. However, a part of the absorption solvent S1 discharged from the regenerator 6 is transferred to the reboiler 7, and the remainder of the absorption solvent S1 discharged from the regenerator 6 is transferred to the absorber 3. At this time, the regenerative heat exchanger 5 exchanges heat between the absorption solvent S1 transferred from the regenerator 6 to the absorber 3 and the absorption solvent S2 transferred from the absorber 3 to the regenerator 6. As a result, the absorption solvent S1 is cooled in the regenerative heat exchanger 5. The absorption solvent S1 is further cooled in the lean liquid cooler 9.

[0035] In this way, the absorbing solvents S1 and S2 circulate between the absorber 3 and the regenerator 6. The absorbing solvent (lean solvent) S1 is transferred from the regenerator 6 to the absorber 3 and is transformed into the absorbing solvent (rich solvent) S2 in the absorber 3. The absorbing solvent (rich solvent) S2 is transferred from the absorber 3 to the regenerator 6 and is transformed into the absorbing solvent (lean solvent) S1 in the regenerator 6.

[0036] The control unit 21 controls various operations of the carbon dioxide capture system 101. Examples of the control unit 21 include a processor, an electric circuit, and a computer. The control unit 21 controls, for example, the rotation speeds of the rich liquid transfer pump 4 and the lean liquid transfer pump 8, the cooling operations of the lean liquid cooler 9, the absorber outlet cooler 11, and the regenerator outlet cooler 13, and the heating operation of the reboiler 7. The control unit 21 may also perform various information processing operations, such as generating notifications to users of the carbon dioxide capture system 101.

[0037] FIG. 2 is a schematic diagram partially showing the configuration of the carbon dioxide capture system 101 of the first embodiment.

[0038] Fig. 2 shows an enlarged view of a portion of the carbon dioxide capture system 101 shown in Fig. 1. Fig. 2 shows the above-mentioned exhaust gas line 1, oxygen separator 2, and control unit 21. As shown in Fig. 2, the carbon dioxide capture system 101 further includes an oxygen concentration detector 31 and an exhaust gas blower 32.

[0039] As described above, the oxygen separator 2 includes a separation section 2a, a liquid reservoir section 2b, and one or more composite membranes 2c. The separation section 2a is housed within the oxygen separator 2 so as to be detachable from the oxygen separator 2. The liquid reservoir section 2b is located below the separation section 2a within the oxygen separator 2. The oxygen separator 2 has an inlet for the flue gas G1 below the separation section 2a and an outlet for the treated flue gas G3 above the separation section 2a. In FIG. 2, the outlet for the treated flue gas G3 is provided at the top of the oxygen separator 2.

[0040] The oxygen separator 2 raises the exhaust gas G1 within the oxygen separator 2 so that the exhaust gas G1 passes through the separation section 2a. As a result, oxygen gas is separated from the exhaust gas G1 within the separation section 2a, and the oxygen concentration of the exhaust gas G1 is reduced. As a result, the oxygen concentration in the exhaust gas G3 at the outlet of the oxygen separator 2 becomes lower than the oxygen concentration in the exhaust gas G1 at the inlet of the oxygen separator 2.

[0041] The separation section 2a is composed of one or more composite membranes 2c. The oxygen gas contained in the flue gas G1 and the other component gases contained in the flue gas G1 have different permeation rates through these composite membranes 2c. As a result, when the flue gas G1 passes through these composite membranes 2c, oxygen gas is separated from the flue gas G1. In this embodiment, these composite membranes 2c also separate nitrogen gas from the flue gas G1. As a result, the nitrogen concentration in the flue gas G3 at the outlet of the oxygen separator 2 is lower than the nitrogen concentration in the flue gas G1 at the inlet of the oxygen separator 2. Conversely, the carbon dioxide concentration in the flue gas G3 at the outlet of the oxygen separator 2 is higher than the carbon dioxide concentration in the flue gas G1 at the inlet of the oxygen separator 2. This makes it possible to improve the separation performance of carbon dioxide gas from the flue gas G3 in the absorber 3 and reduce the cost of separating carbon dioxide gas.

[0042] Within the oxygen separator 2, a pressure difference occurs between a region (feed region) on the inlet side of the composite membrane 2c for the exhaust gas G1 and a region (permeation region) on the outlet side of the composite membrane 2c for the exhaust gas G3. The oxygen separator 2 causes the exhaust gas G1 to flow across the surface of the composite membrane 2c, and this pressure difference separates oxygen gas from the exhaust gas G1. As a result, exhaust gas G3 containing the exhaust gas G1 from which oxygen gas has been separated is discharged from the outlet of the oxygen separator 2.

[0043] 2, the oxygen separator 2 has an inlet for exhaust gas G1 in the lower part of the oxygen separator 2, an outlet for oxygen-rich gas G2 in the middle part of the oxygen separator 2, and an outlet for treated exhaust gas G3 in the upper part of the oxygen separator 2. The one or more composite membranes 2c in the separation section 2a separate the feed region from the permeate region so that the gas in the feed region and the gas in the permeate region do not mix. In other words, these composite membranes 2c serve as a barrier between the feed region and the permeate region.

[0044] Each composite membrane 2c may be an organic-inorganic composite membrane containing an organic substance and an inorganic substance, or an organic-organic composite membrane containing different organic substances. The organic membrane within the organic-inorganic composite membrane and one of the organic membranes within the organic-organic composite membrane are examples of a first material, while the inorganic membrane within the organic-inorganic composite membrane and the other organic membrane within the organic-organic composite membrane are examples of a second material. In this embodiment, each composite membrane 2c within the separation section 2a is an organic-inorganic composite membrane that combines an organic substance and an inorganic substance. According to this embodiment, by using an organic-inorganic composite membrane for each composite membrane 2c, it is possible to enjoy both the advantage of inorganic materials, such as improved performance of the composite membrane 2c, and the advantage of organic materials, such as easier processing of the composite membrane 2c.

[0045] The carbon dioxide capture system 101 may further include a cooler upstream of the oxygen separator 2 to lower the temperature of the flue gas G1. For example, if the flue gas G1 is a combustion exhaust gas emitted from an exhaust gas emission facility that generates a large amount of carbon dioxide gas, the temperature of the flue gas G1 may become very high. In this case, it is desirable to lower the temperature of the flue gas G1 using a cooler before introducing the flue gas G1 into the oxygen separator 2. This makes it possible to alleviate the constraints on the heat resistance strength of the composite membrane 2c, which is an organic-inorganic composite membrane. Furthermore, the cooler may cool the flue gas G1 using a cooling medium such as industrial water, tap water, or seawater, or may cool the flue gas G1 using electricity. The cooling medium may be a cooling liquid or a cooling gas.

[0046] Next, the oxygen separator 2 will be described in further detail.

[0047] The pressure of the exhaust gas G1 supplied into the oxygen separator 2 is preferably 0.005 to 0.1 MPaG, and more preferably 0.01 to 0.05 MPaG. Therefore, the carbon dioxide capture system 101 may be provided with a device for adjusting the pressure of the exhaust gas G1 between the exhaust gas discharge facility and the oxygen separator 2.

[0048] Each composite membrane 2c may have any configuration. For example, each composite membrane 2c may be an asymmetric flat membrane or an asymmetric hollow fiber membrane. The separation unit 2a of this embodiment is configured with a membrane module including a plurality of asymmetric hollow fiber membranes as the one or more composite membranes 2c. This makes it possible to efficiently separate oxygen gas from the exhaust gas G1.

[0049] Each composite membrane 2c may have a membrane structure in which a matrix resin (organic substance) and a functional molecular material (inorganic substance) are dispersed. The matrix resin is, for example, a polymer material such as polyimide or polysulfone silicone rubber. The functional molecular material is, for example, a porous metal-organic framework (MOF).

[0050] The matrix resin of each composite membrane 2c may be, for example, a resin used to form a gas processing membrane. Examples of the matrix resin include aromatic polyimide, aromatic polyamide, polysulfone, polydimethylsiloxane, polysubstituted acetylene, poly-4-methylpentene, and natural rubber. The matrix resin of each composite membrane 2c may be other resins. Note that the composite membrane 2c, which is an organic-organic composite membrane, may contain one of these examples and another of these examples.

[0051] Examples of functional molecular materials for each composite membrane 2c include MOFs, dendrimers, silica nanoparticles, and zeolites. Other materials may also be used for the functional molecular materials for each composite membrane 2c. Examples of the MOFs include MIL-53, HKUST-1, CALF-20, ZIF-8, and MOF-177. Other materials may also be used for the MOFs for each composite membrane 2c.

[0052] For example, the MOF of each composite membrane 2c may be composed of a metal oxalate, a cycloazocarbyl compound, and a bidentate organic ligand, and in this case, the MOF may contain three components, i.e., a metal oxalate, a cycloazocarbyl compound, and a bidentate organic ligand, as well as other components.

[0053] In a MOF containing a metal oxalate, a cycloazocarbyl compound, and a bidentate organic ligand, the molar ratio of the cycloazocarbyl compound to the metal oxalate is preferably 2 to 6, and more preferably 3 to 5. If the molar ratio of the cycloazocarbyl compound to the metal oxalate is less than 2, a problem of no pores being formed may occur. When the molar ratio is 3 to 5, more than 2 moles of the cycloazocarbyl compound can be used per mole of the metal oxalate, and an excess amount of the cycloazocarbyl compound relative to the metal oxalate can be used.

[0054] In MOFs containing a metal oxalate, a cycloazocarbyl compound, and a bidentate organic ligand, the molar ratio of the bidentate organic compound to the cycloazocarbyl compound is preferably 0.02 to 0.1, and more preferably 0.03 to 0.07. If the molar ratio of the bidentate organic compound to the cycloazocarbyl compound is less than 0.02, the effect of the bidentate ligand may be insufficient. On the other hand, if the molar ratio of the bidentate organic compound to the cycloazocarbyl compound is greater than 0.1, the pore-forming reaction may be inhibited.

[0055] When each composite film 2c contains a matrix resin and a functional molecular material, the ratio (content) of the functional molecular material to the matrix resin and functional molecular material in each composite film 2c is, for example, preferably 0.1 to 50 mass %, more preferably 0.5 to 20 mass %. This condition is also applicable when the organic matter in each composite film 2c is a material other than the matrix resin or when the inorganic matter in each composite film 2c is a material other than the functional molecular material.

[0056] Next, other components within the carbon dioxide capture system 101 will be described in detail.

[0057] The oxygen concentration detector 31 and the exhaust gas blower 32 are provided in this order on the exhaust gas line 1 between the oxygen separator 2 and the absorber 3. The exhaust gas blower 32 sends the exhaust gas G3 from the oxygen separator 2 to the absorber 3. The oxygen concentration detector 31 detects the oxygen concentration of the exhaust gas G3 flowing through the exhaust gas line 1, and outputs a signal indicating the detection result of the oxygen concentration to the control unit 21.

[0058] The control unit 21 performs information processing based on the detection result of the oxygen concentration detected by the oxygen concentration detector 31. For example, when the oxygen concentration is higher than a predetermined value, the control unit 21 generates a notification urging the user to inspect or replace the separation unit 2a. Examples of such notifications include displaying the notification content on a monitor, turning on a warning light urging the user to inspect or replace the separation unit 2a, or emitting a warning sound urging the user to inspect or replace the separation unit 2a. The notification content may be displayed on the monitor of the control unit 21, or may be remotely displayed on a monitor of a device other than the control unit 21.

[0059] The oxygen separator 2 may be installed in a carbon dioxide capture system of a type different from the carbon dioxide capture system 101, or may be installed in a gas treatment device other than a carbon dioxide capture system. In this case, the device into which the treated flue gas G3 is introduced may be an absorber of a type different from the absorber 3, or may be a gas treatment device other than an absorber. This also applies to second to fourth embodiments described later.

[0060] Furthermore, the separation unit 2a of this embodiment includes a non-liquid composite membrane 2c. In this case, it is desirable to operate the oxygen separator 2 so that the supply side region is under high pressure, and therefore it is desirable to provide the separation unit 2a at the most upstream position in the carbon dioxide capture system 101. In some cases, the carbon dioxide capture system 101 is provided with a heat exchanger upstream of the absorber 3 that cools the exhaust gas introduced into the absorber 3. In this case, it is desirable to provide the oxygen separator 2 upstream of this heat exchanger.

[0061] Next, an example of the operation of the carbon dioxide capture system 101 will be described with reference to FIGS.

[0062] The flue gas G1 introduced into the carbon dioxide capture system 101 first flows into the oxygen separator 2. In the oxygen separator 2, the flue gas G1 comes into contact with the separation section 2a; specifically, the flue gas G1 passes through the separation section 2a, thereby separating the oxygen contained in the flue gas G1 (oxygen separation process). As a result, the flue gas G1 changes into treated flue gas G3, which is discharged from the oxygen separator 2 and sent to the absorber 3. The oxygen concentration detector 31 detects the oxygen concentration of the flue gas G3 between the oxygen separator 2 and the absorber 3, and provides information regarding the detection result of the oxygen concentration to the control unit 21.

[0063] The flue gas G3 discharged from the oxygen separator 2 flows into the absorber 3. The absorber 3 treats the flue gas G3 with an absorption solvent (lean solvent) S1 as a treatment agent (absorption process (gas treatment process)). Specifically, the absorber 3 brings the flue gas G3 into contact with the absorption solvent S1, causing the carbon dioxide contained in the flue gas G3 to be absorbed by the absorption solvent S1. This separates the carbon dioxide from the flue gas G3. The absorber 3 discharges an absorber discharge gas containing the flue gas G3 from which the carbon dioxide has been separated, and an absorption solvent (rich solvent) S2 converted from the absorption solvent S1. The absorber discharge gas is released from the top of the absorber 3 to the outside of the absorber 3.

[0064] The absorption solvent S2 discharged from the absorber 3 flows into the regenerator 6. The regenerator 6 heats the absorption solvent S2 to strip carbon dioxide (and water vapor) from the absorption solvent S2 (regeneration step). The regenerator 6 discharges a regenerator exhaust gas containing the stripped carbon dioxide and an absorption solvent (lean solvent) S1 regenerated from the absorption solvent S2. The regenerator exhaust gas is released from the top of the regenerator 6 to the outside.

[0065] The absorbing solvent S1 discharged from the regenerator 6 flows again into the absorber 3. In this way, the absorbing solvents S1 and S2 are repeatedly used for the carbon dioxide separation process.

[0066] If the control unit 21 determines during this carbon dioxide separation process that the oxygen concentration detected by the oxygen concentration detector 31 is equal to or greater than a predetermined value, it generates a notification urging inspection or replacement of the separation unit 2a. When this notification is generated, the manager of the carbon dioxide capture system 101 may replace the separation unit 2a with a new separation unit. Such replacement work may be performed, for example, by temporarily stopping the introduction of the exhaust gas G1 into the oxygen separator 2.

[0067] Next, the advantages of the carbon dioxide capture system 101 will be described.

[0068] In the carbon dioxide capture system 101 of this embodiment, if oxygen contained in the exhaust gas G1 is mixed into the absorption solvent S1, the absorption solvent S1 may be oxidized (decomposed), and the carbon dioxide absorption performance of the absorption solvent S1 may decrease. If the absorption solvent S1 containing oxygen is continued to be used, the carbon dioxide absorption performance of the absorption solvent S1 may further decrease. The adverse effect of the oxidation of the absorption solvent S1 on the carbon dioxide capture system 101 increases over time with repeated use of the absorption solvent S1.

[0069] Therefore, in the carbon dioxide capture system 101 of this embodiment, oxygen is separated from the flue gas G1 by the oxygen separator 2, and the treated flue gas G3 discharged from the oxygen separator 2 is introduced into the absorber 3. Therefore, according to this embodiment, it is possible to suppress the mixing of oxygen into the absorption solvent S1, and it is possible to maintain good performance of the absorption solvent S1. Specifically, the mixing of oxygen into the absorption solvent S1 is suppressed, and oxidation (decomposition) of the absorption solvent S1 is prevented or suppressed, thereby maintaining good performance of the absorption solvent S1.

[0070] Furthermore, according to this embodiment, it is possible to suppress entrainment of oxygen with the carbon dioxide gas in the regeneration tower exhaust gas, which makes it possible to increase the purity of the carbon dioxide as a product and improve the product quality.

[0071] Furthermore, in this embodiment, the oxygen concentration of the treated exhaust gas G3 before it flows into the absorber 3 is detected by the oxygen concentration detector 31. Therefore, according to this embodiment, it is possible to monitor the state of the oxygen separator 2, and for example, it is possible to replace the separation section 2a in response to a deterioration in the performance of the oxygen separator 2. This makes it possible to more effectively suppress the mixing of oxygen into the absorption solvent S1.

[0072] Furthermore, the oxygen separator 2 of this embodiment has a separation unit 2a that is detachable from the oxygen separator 2. This makes it possible to easily manufacture the oxygen separator 2. Furthermore, when the carbon dioxide capture system 101 is small, it becomes possible to employ a small oxygen separator as the oxygen separator 2 in the carbon dioxide capture system 101, which makes it possible to easily replace the separation unit 2a. As a result, the oxygen separator 2 is easy to use.

[0073] Furthermore, the composite membrane 2c in the oxygen separator 2 of this embodiment can also separate nitrogen from the exhaust gas G1. This makes it possible to increase the proportion of carbon dioxide in the exhaust gas G3. As a result, it becomes possible to absorb a large amount of carbon dioxide with a small flow rate of the absorption solvent S1, and it becomes possible to reduce the flow rate of the absorption solvent S1 in the absorber 3. This makes it possible to reduce the operating costs of the carbon dioxide capture system 101.

[0074] As a result of experiments, it was found that when the absorption solvent is repeatedly brought into contact with an oxygen-rich gas, the absorption solvent is more easily decomposed than when the absorption solvent is repeatedly brought into contact with a nitrogen-rich gas. According to this embodiment, by separating oxygen from the exhaust gas G1, it is possible to effectively suppress the decomposition of the absorption solvent.

[0075] Furthermore, experimental results have revealed that the degree of decomposition of the absorbing solvent varies depending on the partial pressure of oxygen gas in the gas that comes into contact with the absorbing solvent. According to this embodiment, by separating oxygen from the exhaust gas G1, it is possible to reduce the partial pressure of oxygen gas in the exhaust gas G1, thereby making it possible to effectively suppress the decomposition of the absorbing solvent.

[0076] (Second embodiment) FIG. 3 is a schematic diagram partially showing the configuration of a carbon dioxide capture system 102 according to the second embodiment.

[0077] The configuration of the carbon dioxide capture system 102 of this embodiment is similar to the configuration of the carbon dioxide capture system 101 of the first embodiment. However, the carbon dioxide capture system 102 of this embodiment has a configuration in which the components shown in Fig. 2 are replaced with the components shown in Fig. 3. The carbon dioxide capture system 102 of this embodiment will be described with reference to Figs. 1 and 3.

[0078] Whereas the carbon dioxide capture system 101 of the first embodiment includes one oxygen separator 2, the carbon dioxide capture system 102 of the present embodiment includes two oxygen separators 2. In the present embodiment, one oxygen separator 2 is also referred to as "oxygen separator 2-1," and the other oxygen separator 2 is also referred to as "oxygen separator 2-2." The configuration of the oxygen separator 2-1 and the configuration of the oxygen separator 2-2 are the same as the configuration of the oxygen separator 2 of the first embodiment. The oxygen separator 2-1 is an example of a first oxygen separator, and the oxygen separator 2-2 is an example of a second oxygen separator.

[0079] Like the carbon dioxide capture system 101 of the first embodiment, the carbon dioxide capture system 102 of this embodiment includes an oxygen concentration detector 31 and an exhaust gas blower 32. The carbon dioxide capture system 102 of this embodiment further includes a supply-side three-way valve 33 and a discharge-side three-way valve 34.

[0080] The supply-side three-way valve 33 is provided on the exhaust gas line 1 upstream of the oxygen separators 2-1 and 2-2. Specifically, the supply-side three-way valve 33 is disposed between an exhaust gas discharge facility (not shown) and the oxygen separators 2-1 and 2-2. On the other hand, the discharge-side three-way valve 34 is provided on the exhaust gas line 1 downstream of the oxygen separators 2-1 and 2-2. Specifically, the discharge-side three-way valve 34 is disposed between the oxygen separators 2-1 and 2-2 and the oxygen concentration detector 31.

[0081] In this embodiment, the exhaust gas line 1 branches into a first branch and a second branch between the supply-side three-way valve 33 and the discharge-side three-way valve 34. The oxygen separator 2-1 is provided on the first branch, and the oxygen separator 2-2 is provided on the second branch. The oxygen separators 2-1 and 2-2 are arranged in parallel with each other between the supply-side three-way valve 33 and the discharge-side three-way valve 34.

[0082] Exhaust gas G1 from the exhaust gas discharge facility is introduced into the oxygen separators 2-1 and 2-2 via a supply-side three-way valve 33. The supply-side three-way valve 33 is configured to receive the exhaust gas G1 from an inlet port, supply the exhaust gas G1 to the oxygen separator 2-1 from a first outlet port, and supply the exhaust gas G1 to the oxygen separator 2-2 from a second outlet port. The control unit 21 controls the supply-side three-way valve 33 to switch the state of the supply-side three-way valve 33 from a first state to a second state (or from the second state to the first state). In the first state, the exhaust gas G1 from the inlet port is supplied to the oxygen separator 2-1 from the first outlet port. In the second state, the exhaust gas G1 from the inlet port is supplied to the oxygen separator 2-2 from the second outlet port.

[0083] The exhaust gas G3 from the oxygen separators 2-1 and 2-2 is sent to the absorber 3 via a discharge-side three-way valve 34. The discharge-side three-way valve 34 is configured to receive the exhaust gas G3 discharged from the oxygen separator 2-1 at a first inlet port, receive the exhaust gas G3 discharged from the oxygen separator 2-2 at a second inlet port, and discharge the received exhaust gas G3 from an outlet port to the absorber 3. The control unit 21 controls the discharge-side three-way valve 34 to switch the state of the discharge-side three-way valve 34 from a first state to a second state (or from the second state to the first state). In the first state, the exhaust gas G3 from the first inlet port is discharged from the outlet port to the absorber 3. In the second state, the exhaust gas G3 from the second inlet port is discharged from the outlet port to the absorber 3.

[0084] The control unit 21 performs information processing based on the detection result of the oxygen concentration detected by the oxygen concentration detector 31. For example, when the oxygen concentration is greater than a predetermined value, the control unit 21 switches the oxygen separator 2 to be used from one of the oxygen separators 2-1 and 2-2 to the other. Switching from the oxygen separator 2-1 to the oxygen separator 2-2 is performed by switching the state of the supply-side three-way valve 33 from the first state to the second state and switching the state of the discharge-side three-way valve 34 from the first state to the second state. On the other hand, switching from the oxygen separator 2-2 to the oxygen separator 2-1 is performed by switching the state of the supply-side three-way valve 33 from the second state to the first state and switching the state of the discharge-side three-way valve 34 from the second state to the first state. This makes it possible to automatically switch the oxygen separator 2 to be used.

[0085] When the oxygen concentration is greater than a predetermined value, the control unit 21 may generate a notification to prompt the user to switch the oxygen separator 2 to be used from one of the oxygen separators 2-1 and 2-2 to the other. Examples of such a notification include displaying the notification content on a monitor, turning on a warning light to prompt the user to switch, or emitting a warning sound to prompt the user to switch. The notification content may be displayed on the monitor of the control unit 21, or may be remotely displayed on a monitor of a device other than the control unit 21. This makes it possible to manually switch the oxygen separator 2 to be used.

[0086] According to this embodiment, such switching makes it possible to put one of the oxygen separators 2-1, 2-2 in an in-use state and the other of the oxygen separators 2-1, 2-2 in an unused state. This makes it possible to perform maintenance on the oxygen separator 2 that is not in use while continuing to operate the carbon dioxide capture system 102 using the oxygen separator 2 that is in use. According to this embodiment, it is possible to perform maintenance on the oxygen separator 2 without stopping the carbon dioxide capture system 102; in other words, it is possible to perform maintenance on the oxygen separator 2 while maintaining the oxygen separation performance of the carbon dioxide capture system 102. The configuration of this embodiment is advantageous, for example, when continuous operation of the carbon dioxide capture system 102 is desired.

[0087] The carbon dioxide capture system 102 of this embodiment may include three or more oxygen separators 2 arranged in parallel with each other. In this case, the configuration of each oxygen separator 2 may be the same as the configuration of the oxygen separator 2 of the first embodiment.

[0088] Furthermore, within each oxygen separator 2 of this embodiment, a pressure difference occurs between a region (supply region) on the inlet side of the composite membrane 2c for the exhaust gas G1 and a region (permeation region) on the outlet side of the composite membrane 2c for the exhaust gas G3. Each oxygen separator 2 flows the exhaust gas G1 over the surface of the composite membrane 2c, and this pressure difference separates oxygen gas from the exhaust gas G1. As a result, exhaust gas G3 containing the exhaust gas G1 separated from the oxygen gas is discharged from the outlet of each oxygen separator 2. Because the pressure within the supply region increases as the temperature within the supply region increases, the temperature of the exhaust gas G1 introduced into each oxygen separator 2 may be high. Furthermore, because a high pressure is desirable in the supply region, each oxygen separator 2 is desirably provided at the most upstream position in the carbon dioxide capture system 102 and on the suction side of the exhaust gas blower 32.

[0089] (Third embodiment) FIG. 4 is a schematic diagram partially showing the configuration of a carbon dioxide capture system 103 according to the third embodiment.

[0090] The configuration of the carbon dioxide capture system 103 of this embodiment is similar to the configuration of the carbon dioxide capture system 101 of the first embodiment. However, the carbon dioxide capture system 103 of this embodiment has a configuration in which the components shown in Fig. 2 are replaced with the components shown in Fig. 4. The carbon dioxide capture system 103 of this embodiment will be described with reference to Figs. 1 and 4.

[0091] Like the carbon dioxide capture system 101 of the first embodiment, the carbon dioxide capture system 103 of this embodiment includes an oxygen concentration detector 31 and an exhaust gas blower 32. The carbon dioxide capture system 103 of this embodiment further includes an exhaust gas heat exchanger 35.

[0092] The exhaust gas heat exchanger 35 is provided on the exhaust gas line 1 between the oxygen concentration detector 31 and the exhaust gas blower 32. Therefore, the exhaust gas heat exchanger 35 is located downstream of the oxygen concentration detector 31 and upstream of the exhaust gas blower 32. The exhaust gas heat exchanger 35 may be located upstream of the oxygen concentration detector 31, and more specifically, may be provided between the oxygen separator 2 and the oxygen concentration detector 31. The exhaust gas heat exchanger 35 is an example of a cooler.

[0093] The exhaust gas heat exchanger 35 cools the exhaust gas G3 by heat exchange, which makes it possible to introduce the cooled exhaust gas G3 into the absorber 3, thereby making it possible to suppress the heat of the exhaust gas G3 from adversely affecting the absorption solvent S1.

[0094] The exhaust gas heat exchanger 35 exchanges heat between the exhaust gas G3 and a cooling medium. The cooling medium may be a gas or a liquid. Examples of the cooling medium include the absorber discharge gas discharged from the absorber 3 and the absorption solvent (rich solvent) S2 discharged from the absorber 3. When the cooling medium is the absorber discharge gas, the cooling medium may be the absorber discharge gas before being cooled in the absorber outlet cooler 11, or the absorber discharge gas after being cooled in the absorber outlet cooler 11. Furthermore, the absorber discharge gas discharged from the exhaust gas heat exchanger 35 may be returned to the upstream side of the absorber outlet cooler 11, or may be sent to the absorber outlet separator 12.

[0095] The separation unit 2a of this embodiment includes one or more composite membranes 2c. In this case, the oxygen separator 2 may be operated at a high temperature. The reason is that when the oxygen separator 2 reaches a high temperature, the oxygen separator 2 becomes high pressure, which tends to promote oxygen separation in the composite membrane 2c. In this embodiment, the oxygen separator 2 is provided upstream of the exhaust gas heat exchanger 35, so the oxygen separator 2 separates oxygen from the high-temperature exhaust gas G1 before it is cooled by the exhaust gas heat exchanger 35. Therefore, according to this embodiment, the separation unit 2a can effectively separate oxygen from the exhaust gas G1.

[0096] (Fourth embodiment) FIG. 5 is a schematic diagram partially showing the configuration of a carbon dioxide capture system 104 according to the fourth embodiment.

[0097] The configuration of the carbon dioxide capture system 104 of this embodiment is similar to the configuration of the carbon dioxide capture system 101 of the first embodiment. However, the carbon dioxide capture system 104 of this embodiment has a configuration in which the components shown in Fig. 2 are replaced with the components shown in Fig. 5. The carbon dioxide capture system 104 of this embodiment will be described with reference to Figs. 1 and 5.

[0098] Whereas the carbon dioxide capture system 101 of the first embodiment includes one oxygen separator 2, the carbon dioxide capture system 104 of the present embodiment includes two oxygen separators 2. This is the same as in the second embodiment. In the present embodiment, as in the second embodiment, one oxygen separator 2 will also be referred to as "oxygen separator 2-1," and the other oxygen separator 2 will also be referred to as "oxygen separator 2-2." The configurations of the oxygen separator 2-1 and the oxygen separator 2-2 are the same as the configurations of the oxygen separator 2 of the first embodiment.

[0099] Like the carbon dioxide capture system 101 of the first embodiment, the carbon dioxide capture system 104 of this embodiment includes an oxygen concentration detector 31 and an exhaust gas blower 32. Like the carbon dioxide capture system 102 of the second embodiment, the carbon dioxide capture system 104 of this embodiment further includes a supply-side three-way valve 33 and a discharge-side three-way valve 34. Like the carbon dioxide capture system 103 of the third embodiment, the carbon dioxide capture system 104 of this embodiment further includes an exhaust gas heat exchanger 35.

[0100] The carbon dioxide capture system 104 of the present embodiment has a configuration that combines the configuration of the carbon dioxide capture system 102 of the second embodiment and the configuration of the carbon dioxide capture system 103 of the third embodiment. Therefore, according to the present embodiment, it is possible to enjoy the advantages of the second embodiment and the third embodiment.

[0101] Although several embodiments have been described above, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. The novel devices, methods, and systems described herein may be embodied in various other forms. Furthermore, various omissions, substitutions, and modifications may be made to the forms of the devices, methods, and systems described herein without departing from the spirit of the invention. The appended claims and their equivalents are intended to cover such forms and modifications that fall within the scope and spirit of the invention. [Explanation of symbols]

[0102] 1: Exhaust gas line, 2, 2-1, 2-2: Oxygen separator, 2a: separation section, 2b: liquid reservoir section, 2c: composite membrane, 3: absorber, 3a: packed bed, 3b: liquid reservoir, 4: rich liquid transfer pump, 5: regeneration heat exchanger, 6: regenerator, 6a: packed bed, 6b: liquid reservoir, 7: Reboiler, 8: Lean liquid transfer pump, 9: Lean liquid cooler, 11: absorber outlet cooler, 12: absorber outlet separator, 13: regenerator outlet cooler, 14: regenerator outlet separator, 15: condensate transfer pump, 21: control unit, 31: oxygen concentration detector, 32: exhaust gas blower, 33: supply side three-way valve, 34: discharge side three-way valve, 35: exhaust gas heat exchanger, 101, 102, 103, 104: Carbon dioxide capture system

Claims

1. an oxygen separator that separates oxygen gas contained in the exhaust gas and discharges a first gas containing the exhaust gas separated from the oxygen gas; a gas treatment device that treats the first gas with a treatment agent and discharges a second gas containing the first gas treated with the treatment agent, The oxygen separator comprises a composite membrane containing a first material that is an organic substance and a second material that is an inorganic substance or an organic substance, and the exhaust gas is supplied to the composite membrane to separate the oxygen gas from the exhaust gas.

2. 2. The gas treatment device of claim 1, wherein the organic of the first or second material comprises aromatic polyimide, aromatic polyamide, polysulfone, polydimethylsiloxane, polysubstituted acetylene, poly-4-methylpentene, or natural rubber.

3. The gas treatment device of claim 1 , wherein the inorganic film of the second material comprises a metal organic framework (MOF), a dendrimer, silica nanoparticles, or a zeolite.

4. 4. The gas treatment apparatus of claim 3, wherein the MOF comprises MIL-53, HKUST-1, CALF-20, ZIF-8, or MOF-177.

5. 4. The gas treatment device of claim 3, wherein the MOF comprises a metal oxalate, a cycloazocarbyl compound, and a bidentate organic ligand.

6. 6. The gas treatment device of claim 5, wherein the molar ratio of cycloazocarbyl compound to metal oxalate in the MOF is 2-6.

7. 6. The gas treatment device according to claim 5, wherein the molar ratio of the bidentate organic compound to the cycloazocarbyl compound in the MOF is 0.02 to 0.

1.

8. 2. The gas treatment device according to claim 1, wherein when the first material is the organic material and the second material is the inorganic material, a ratio of the inorganic material to the organic material and the inorganic material in the composite membrane is 0.1 to 50 mass %.

9. The gas treatment device of claim 1 , wherein the composite membrane comprises an asymmetric flat membrane or an asymmetric hollow fiber membrane.

10. The gas treatment device according to claim 1 , wherein the oxygen separator reduces the oxygen concentration of the first gas discharged from the oxygen separator to a value lower than the oxygen concentration of the exhaust gas introduced into the oxygen separator.

11. The gas treatment device according to claim 1 , further comprising a cooler provided between the oxygen separator and the gas processor for cooling the first gas.

12. The gas treatment device according to claim 11 , wherein the cooler is a heat exchanger that cools the first gas by heat exchange.

13. a detector for detecting an oxygen concentration of the first gas; a control unit that processes information based on the oxygen concentration detected by the detector; The gas treatment device of claim 1 further comprising:

14. The oxygen separator includes first and second oxygen separators arranged in parallel with each other, 14. The gas processing device according to claim 13, wherein the control unit switches the oxygen separator to be used from one of the first and second oxygen separators to the other, or generates a notification prompting the user to switch the oxygen separator to be used from one of the first and second oxygen separators to the other, based on the oxygen concentration detected by the detector.

15. Separating oxygen gas contained in the exhaust gas in an oxygen separator, and discharging a first gas containing the exhaust gas separated from the oxygen gas from the oxygen separator; treating the first gas with a treatment agent in a gas treatment device, and discharging a second gas containing the first gas treated with the treatment agent from the gas treatment device; This includes: The oxygen separator comprises a composite membrane containing a first material that is an organic substance and a second material that is an inorganic substance or an organic substance, and the exhaust gas is supplied to the composite membrane to separate the oxygen gas from the exhaust gas.

16. an oxygen separator that separates oxygen gas contained in the exhaust gas and discharges a first gas containing the exhaust gas separated from the oxygen gas; an absorber that absorbs carbon dioxide contained in the first gas into an absorption solvent and discharges the absorption solvent that has absorbed the carbon dioxide and a second gas that contains the first gas from which the carbon dioxide has been removed; a regenerator that strips the carbon dioxide from the absorption solvent discharged from the absorber and discharges the absorption solvent from which the carbon dioxide has been stripped and a third gas containing the carbon dioxide stripped from the absorption solvent, The oxygen separator comprises a composite membrane containing a first material that is an organic substance and a second material that is an inorganic substance or an organic substance, and the exhaust gas is supplied to the composite membrane to separate the oxygen gas from the exhaust gas.

17. The carbon dioxide recovery system according to claim 16, wherein the absorber absorbs the carbon dioxide contained in the first gas into the absorption solvent discharged from the regenerator.

18. Separating oxygen gas contained in the exhaust gas in an oxygen separator, and discharging a first gas containing the exhaust gas separated from the oxygen gas from the oxygen separator; Absorbing the carbon dioxide contained in the first gas into an absorption solvent in an absorber, and discharging the absorption solvent that has absorbed the carbon dioxide and a second gas containing the first gas from which the carbon dioxide has been removed from the absorber; The carbon dioxide is stripped from the absorption solvent discharged from the absorber in a regenerator, and the absorption solvent from which the carbon dioxide has been stripped and a third gas containing the carbon dioxide stripped from the absorption solvent are discharged from the regenerator. This includes: The oxygen separator comprises a composite membrane containing a first material that is an organic substance and a second material that is an inorganic substance or an organic substance, and the exhaust gas is supplied to the composite membrane to separate the oxygen gas from the exhaust gas.

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