Carbon-dioxide recovery device

Abstract

To provide a carbon-dioxide recovery device that is able to recover high-purity CO2, with low energy.SOLUTION: A carbon-dioxide recovery device 1 includes: a first recovery unit 100 configured to recover CO2 by an electric field system for switching adsorption and desorption of CO2 in a first adsorbent 110 by means of an electrochemical reaction; and a second recovery unit 200 configured to recover CO2 by a system different from that of the first recovery unit 100, by changing a partial pressure of CO2 in a second housing 230 or a temperature of a second adsorbent 220, thereby switching adsorption and desorption of CO2 in the second adsorbent 220. The second housing 230 of the second recovery unit 200 is connected to a rear stage of a first housing 120 of the first recovery unit 100, and an intermediate gas containing CO2 recovered by the first recovery unit 100 is introduced from the first housing 120. The second recovery unit 200 recovers CO2 by causing the second adsorbent 220 to adsorb CO2 contained in the intermediate gas and causing the second adsorbent 220 to desorb CO2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a carbon dioxide capture device. [Background technology]

[0002] Conventionally, a gas separation device for separating CO2 from a gaseous mixture has been proposed, for example, in Patent Document 1. The gas separation device includes a porous anode impregnated with an adsorptive compound or a solvent and a porous cathode impregnated with a conductive liquid, separated by an ionic membrane. The gas separation device includes a chamber that houses the anode and cathode electrodes and is provided with an inlet and an outlet for the gaseous mixture.

[0003] The gaseous mixture is then fed into the chamber, electrical power is applied to the anode and cathode electrodes, and CO2 is adsorbed from the gaseous mixture by the adsorbent compounds and retained within the device, and the retained CO2 is desorbed from the adsorbent compounds, allowing for the capture of CO2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2008-528285 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above conventional technology, the gaseous mixture remains in the chamber and in the flow path connected to the chamber, and therefore, when the CO2 adsorbed on the anode is captured, the purity of the captured CO2 is reduced by the gaseous mixture, such as moisture, remaining in the flow path.

[0006] In addition, a method is known in which the inside of the chamber is evacuated using a pump before the CO2 desorption. However, the small amount of gaseous mixture remaining in the flow path affects the purity of the CO2. In addition, a large amount of energy is required to remove the remaining gas to a high vacuum.

[0007] In view of the above, an object of the present invention is to provide a carbon dioxide capture device capable of capturing high-purity CO2 with low energy. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides a carbon dioxide capture device that captures CO2 from a CO2-containing gas in two stages, a first capture device (100) and a second capture device (200), comprising: A first recovery device that recovers CO2 of a first purity, the first recovery device having a larger CO2 adsorption amount per body size at a first CO2 concentration than the second recovery device and consuming less energy per amount of CO2 recovered than the second recovery device; A second recovery device that recovers CO2 of a second purity higher than the first purity, and that has a larger CO2 adsorption amount per body size at a second CO2 concentration higher than the first CO2 concentration and consumes less energy per CO2 recovery amount than the first recovery device; It is composed of The first recovery device has a first adsorbent (110) and a first housing (120) configured to be capable of adsorbing and desorbing CO2 contained in the CO2-containing gas, The second recovery vessel is connected downstream of the first housing of the first recovery vessel, and has a second adsorbent (220) and a second housing (230) configured to receive the intermediate gas containing CO2 recovered in the first recovery vessel from the first housing and to adsorb and desorb the CO2 contained in the intermediate gas.

[0009] According to this, the first capture device in the front stage has a higher CO2 capture capacity with low energy in a situation of a first CO2 concentration, which is a low concentration, compared to the second capture device. Also, the second capture device in the rear stage has a higher CO2 capture capacity with low energy in a situation of a second CO2 concentration, which is somewhat higher than the first capture device. Therefore, by combining the first capture device and the second capture device, it is possible to capture higher purity CO2 with low energy.

[0010] In the invention described in claim 2, there is provided a carbon dioxide capture device for capturing CO2 from a CO2-containing gas, a first recovery device (100) that recovers CO2 by an electric field type that has a first adsorbent (110) capable of adsorbing and desorbing CO2 and a first housing (120) that contains the first adsorbent, and that switches between adsorption and desorption of CO2 in the first adsorbent by an electrochemical reaction; a second recovery device (200) that has a second adsorbent (220) capable of adsorbing and desorbing CO2 and a second housing (230) that houses the second adsorbent, and that recovers CO2 by a method different from that of the first recovery device by switching between adsorption and desorption of CO2 in the second adsorbent by changing at least one of the partial pressure of CO2 in the second housing and the temperature of the second adsorbent; Including, The first recovery device introduces a CO2-containing gas into the first housing, adsorbs CO2 contained in the CO2-containing gas onto the first adsorbent, scavenges the first housing, and then recovers CO2 by desorbing CO2 from the first adsorbent. The second housing of the second recovery device is connected to the rear of the first housing of the first recovery device, and the intermediate gas containing CO2 recovered in the first recovery device is introduced from the first housing. The second recovery device recovers CO2 by adsorbing the CO2 contained in the intermediate gas onto a second adsorbent and desorbing the CO2 from the second adsorbent.

[0011] According to this, since the first recovery device employs an electric field type, it is possible to adsorb CO2 even if the concentration of CO2 contained in the CO2-containing gas is low. In the electric field type, gaseous mixtures such as moisture contained in the CO2-containing gas are less likely to be adsorbed by the first adsorbent, so CO2 can be selectively adsorbed by the first adsorbent rather than gaseous mixtures such as moisture.

[0012] In addition, the gaseous mixture, such as moisture, that is not adsorbed by the first adsorbent can be easily removed by scavenging the inside of the first housing, and therefore the energy required for capturing CO2 can be reduced compared to the case where the inside of the first housing is evacuated to a high vacuum.

[0013] Furthermore, since CO2 is further recovered by the second recovery device from the intermediate gas from which gaseous mixtures such as moisture have been removed, it is possible to recover high-purity CO2.

[0014] Therefore, the carbon dioxide capture device disclosed herein can capture high-purity CO2 with low energy consumption.

[0015] In addition, the reference symbols in parentheses for each means described in this column and in the claims indicate the correspondence with the specific means described in the embodiments described later. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic configuration diagram of a carbon dioxide capture device according to a first embodiment. [Diagram 2] FIG. 2 is a specific configuration diagram of a carbon dioxide capture device. [Diagram 3] FIG. 11 is a schematic configuration diagram of a carbon dioxide capture device according to a third embodiment. [Figure 4] 10 is a timing chart for explaining the operation of the carbon dioxide capture device according to the third embodiment. [Diagram 5] FIG. 11 is a diagram showing an operation state of the carbon dioxide capture device according to the third embodiment. [Figure 6] FIG. 11 is a schematic configuration diagram of a carbon dioxide capture device according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals may be used to designate parts corresponding to matters described in the preceding embodiment, and duplicated descriptions may be omitted. In each embodiment, when only a part of the configuration is described, the other embodiment described previously may be applied to the other parts of the configuration.

[0018] It is possible to combine parts of each embodiment that are specifically indicated as being possible to combine with each other. In addition, even if it is not specified that the combination is possible, it is also possible to partially combine the embodiments with each other, the embodiments with the variations, and the variations with each other, as long as there is no particular problem with the combination.

[0019] (First embodiment) The carbon dioxide capture device according to this embodiment captures CO2 from a CO2-containing gas that contains CO2. The CO2-containing gas is, for example, a gas containing CO2, such as the atmosphere, exhaust gas from a vehicle, or exhaust gas from a facility such as a factory.

[0020] Hereinafter, the first embodiment will be described with reference to the drawings. As shown in Fig. 1, the carbon dioxide capture device 1 includes a first capture device 100 and a second capture device 200. Each of the capture devices 100, 200 is a device that separates and captures CO2 from a CO2-containing gas. Each of the capture devices 100, 200 discharges a CO2-removed gas after CO2 is captured, and the captured CO2.

[0021] In this embodiment, the carbon dioxide capture device 1 captures CO2 from a CO2-containing gas in two stages, a first capture device 100 and a second capture device 200. The first capture device 100 is located in the front stage, and the second capture device 200 is located in the rear stage.

[0022] The first collector 100 is a collector that adsorbs less CO2 per unit size than the second collector 200, and is more difficult to purify CO2 with than the second collector 200. However, the first collector 100 is characterized in that it adsorbs more CO2 per unit size at a first CO2 concentration than the second collector 200, and consumes less energy per amount of CO2 captured than the second collector 200. The first collector 100 captures CO2 of a first purity.

[0023] The first CO2 concentration is, for example, the concentration of CO2 contained in the air. Specifically, the first CO2 concentration is a low concentration of 500 ppm to 10,000 ppm (1%). That is, the first recovery device 100 is superior to the second recovery device 200 in adsorbing CO2 in a situation where the CO2 concentration is low.

[0024] Here, concentration and purity are synonymous in that they indicate the proportion of CO2 per certain volume. In this embodiment, the term concentration is used from the viewpoint of the ratio that the gas contains various substances other than CO2 before CO2 is captured. After CO2 is captured, the term purity is used from the viewpoint of the proportion of CO2 finally obtained.

[0025] The second collector 200 is a collector that has a larger CO2 adsorption amount per unit size than the first collector 100 and can purify CO2 to a higher degree than the first collector 100. Furthermore, the second collector 200 has a feature that it has a larger CO2 adsorption amount per unit size than the first collector 100 at a second CO2 concentration that is higher than the first CO2 concentration, and consumes less energy per amount of CO2 captured than the first collector 100.

[0026] The second CO2 concentration is, for example, a CO2 concentration of about 10% or more. That is, the second recovery device 200 is superior to the first recovery device 100 in adsorbing CO2 at a CO2 concentration of about 10% or more.

[0027] The second collector 200 collects CO2 with a second purity that is higher than the first purity.

[0028] The first capture device 100 and the second capture device 200 capture CO2 using different methods. For example, the first capture device 100 captures CO2 using an electric field method. The second capture device 200 captures CO2 using a pressure method, a temperature method, or a pressure-temperature method.

[0029] The electric field type is sometimes called ESA (Electro Swing Adsorption). The pressure type is sometimes called PSA (Pressure Swing Adsorption). The temperature type is sometimes called TSA (Temperature Swing Adsorption). The pressure temperature type is sometimes called PTSA (Pressure and Temperature Swing Adsorption). Furthermore, the electric field type, pressure type, temperature type, and pressure temperature type are sometimes called adsorption separation methods in separation and capture technology. Alternatively, the electric field type, pressure type, temperature type, and pressure temperature type are sometimes included in the technical field of physical adsorption in CO2 capture technology.

[0030] The first recovery device 100 in the first stage recovers CO2 from a CO2-containing gas having a first CO2 concentration, which is a low concentration. For this reason, there is an advantage in recovering CO2 in the first stage using an electric field method, which has a high CO2 capture capacity in a situation of a first CO2 concentration, which is a low concentration, compared to other methods. The capture capacity refers to the amount of CO2 adsorbed per body size being greater than that of the second recovery device 200, and the energy consumption per amount of CO2 captured being less than that of the second recovery device 200. While other methods have a limit to the CO2 capture capacity when the CO2 concentration is low, the electric field method has the characteristic of being independent of the concentration of CO2 contained in the CO2-containing gas.

[0031] The second recovery device 200 in the latter stage recovers CO2 from the intermediate gas containing CO2 at a second CO2 concentration that has been somewhat highly concentrated in the first recovery device 100. For this reason, compared to other methods, it is advantageous to adopt any one of the pressure type, temperature type, and pressure-temperature type in the latter stage, which can recover CO2 with lower energy as the concentration of CO2 becomes higher.

[0032] In this way, when trying to obtain higher purity CO2 with low energy, it is important to capture CO2 in different ways in the front and back stages. In this embodiment, the first capture device 100 captures CO2 using an electric field method, and the second capture device 200 captures CO2 using a pressure method. The specific configurations of each capture device 100, 200 will be described below.

[0033] The first recovery unit 100 has a first adsorbent 110 and a first housing 120. The first recovery unit 100 recovers CO2 by an electric field type that switches between adsorption and desorption of CO2 in the first adsorbent 110 by an electrochemical reaction.

[0034] The first adsorbent 110 is a device capable of adsorbing and desorbing CO2. That is, the first adsorbent 110 is an electrochemical cell that can capture CO2 by adsorbing CO2 and also capture CO2 by desorbing CO2.

[0035] The first adsorbent 110 has a working electrode 111, a counter electrode 112, and an insulating film 113. The working electrode 111, the counter electrode 112, and the insulating film 113 are configured, for example, in a plate shape. The working electrode 111 is a negative electrode. The counter electrode 112 is a positive electrode.

[0036] The working electrode 111 has a first current collector and a first electrode film. The first current collector is a porous conductive member that allows the CO2-containing gas to pass through.

[0037] The first current collecting material may be, for example, a carbonaceous material or a metal material. The carbonaceous material constituting the first current collecting material may be, for example, carbon paper, carbon cloth, nonwoven carbon mat, porous gas diffusion layer (GDL), etc. The metal material constituting the first current collecting material may be, for example, a mesh structure made of metal such as Al, Ni, Ti, or SUS.

[0038] The first electrode film adsorbs and desorbs CO2 from the CO2-containing gas by electrochemical reaction. The first electrode film includes a CO2 adsorbent, a working electrode-side conductive assistant, and a working electrode-side binder.

[0039] The CO2 adsorbent absorbs CO2 by receiving electrons and releases the absorbed CO2 by releasing electrons. For example, polyanthraquinone can be used as the CO2 adsorbent. Alternatively, carbon or metal oxide can be used as the CO2 adsorbent.

[0040] The working electrode-side conductive assistant is a conductive material that forms a conductive path to the CO2 adsorbent. As the working electrode-side conductive assistant, for example, a carbon material such as carbon nanotube, carbon black, graphene, etc. can be used.

[0041] The CO2 adsorbent and the working electrode side conductive assistant may be mixed, for example, by dissolving or dispersing the working electrode side conductive assistant in an organic solvent such as NMP (N-methylpyrrolidone) and bringing the working electrode side conductive assistant dispersed in the organic solvent into contact with the CO2 adsorbent.

[0042] The working electrode side binder is a holding material having adhesive strength. The working electrode side binder holds the CO2 adsorbent and the working electrode side conductive assistant to the first current collector. This ensures the movement of electrons between the first current collector, the CO2 adsorbent, and the working electrode side conductive assistant. In addition, the CO2 adsorbent is less likely to peel off from the first current collector, and the CO2 adsorption amount of the first adsorbent 110 can be suppressed from decreasing over time.

[0043] A non-fluid substance having no fluidity can be used as the working electrode side binder. Examples of the non-fluid substance include a gel-like substance or a solid-like substance. Examples of the gel-like substance include an ionic liquid gel. Examples of the solid-like substance include a solid electrolyte or a conductive resin.

[0044] When using a solid electrolyte as the working electrode binder, it is desirable to use an ionomer made of a polymer electrolyte, etc., in order to increase the contact area with the CO2 adsorbent. When using a conductive resin as the working electrode binder, epoxy resin containing Ag, etc. as a conductive filler, or fluororesin such as polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF) can be used.

[0045] Then, a mixture of the CO2 adsorbent, the working electrode side conductive assistant, and the working electrode side binder is formed, and this mixture is adhered to the first current collector. The CO2 adsorbent and the working electrode side conductive assistant are held in the working electrode side binder. Therefore, the CO2 adsorbent and the working electrode side conductive assistant can be firmly held by the working electrode side binder. In addition, the CO2 adsorbent and the working electrode side conductive assistant are less likely to peel off from the first current collector.

[0046] The counter electrode 112 has a second current collector and a second electrode film. The second current collector may be made of the same material as the first current collector, or may be made of a different material.

[0047] The second electrode film exchanges electrons with the first electrode film, and includes a counter electrode side active material, a counter electrode side conductive assistant, and a counter electrode side binder.

[0048] The counter electrode active material is a supplementary electroactive species that transfers electrons between the CO2 adsorbent of the first electrode film and the counter electrode active material is a material that can transfer electrons by changing the valence of the metal or by transferring charge to and from the π electron cloud.

[0049] As the counter electrode active material, for example, a metal complex that can exchange electrons by changing the valence of the metal ion can be used. Examples of such metal complexes include cyclopentadienyl metal complexes such as ferrocene, nickelocene, and cobaltocene, and porphyrin metal complexes.

[0050] The counter electrode conductive assistant is a conductive material that forms a conductive path to the counter electrode active material. The counter electrode conductive assistant is used by mixing with the counter electrode active material. The counter electrode conductive assistant may be the same material as the working electrode conductive assistant, or may be a different material. The counter electrode conductive assistant is, for example, in a particulate form.

[0051] The counter electrode side binder is a material that can hold the counter electrode side active material and the counter electrode side conductive assistant on the second current collector and has electrical conductivity. The counter electrode side binder may be made of the same material as the working electrode side binder, or may be made of a different material.

[0052] The insulating film 113 is disposed between the first electrode film of the working electrode 111 and the second electrode film of the counter electrode 112. The insulating film 113 is sandwiched between the first electrode film and the second electrode film, and separates the first electrode film and the second electrode film. That is, the insulating film 113 prevents physical contact between the first electrode film and the second electrode film. Furthermore, the insulating film 113 suppresses electrical short-circuiting between the first electrode film and the second electrode film.

[0053] The insulating film 113 may be made of a cellulose film, a polymer, a composite material of a polymer and ceramic, or the like. The insulating film 113 may be made of a porous material.

[0054] An ion conductive member may be provided between the first electrode film and the insulating film 113 or between the second electrode film and the insulating film 113. The ion conductive member promotes conduction to the CO2 adsorbent.

[0055] The electric field cell stack is composed of a plurality of first adsorbents 110. The electric field cell stack is a laminate in which adjacent first adsorbents 110 are arranged with a gap between them. For example, adjacent first adsorbents 110 sandwich a component such as a spacer between them to provide a space between the adjacent first adsorbents 110. The CO2-containing gas flows through the space between the adjacent first adsorbents 110.

[0056] The first housing 120 houses an electrolytic cell stack composed of a plurality of first adsorbents 110. The first housing 120 introduces a CO2-containing gas into the first housing 120 and discharges an intermediate gas containing CO2 captured by the first adsorbent 110. The concentration of CO2 contained in the CO2-containing gas is, for example, a first CO2 concentration. The concentration of CO2 contained in the intermediate gas is, for example, a second CO2 concentration. The second CO2 concentration corresponds to a first purity of CO2 captured by the first capture device 100.

[0057] The second recovery device 200 has a gas supply unit 210, a second adsorbent 220, a second housing 230, and a throttle valve 240. The second recovery device 200 recovers CO2 by a method different from that of the first recovery device 100. In this embodiment, the second recovery device 200 recovers CO2 from the intermediate gas by a pressure method that switches between adsorption and desorption of CO2 in the second adsorbent 220 by changing the partial pressure of CO2 in the second housing 230.

[0058] The gas supply unit 210 is a compressor that pressurizes the intermediate gas and supplies it to the second adsorbent 220. The intermediate gas supplied by the gas supply unit 210 flows toward the second adsorbent 220.

[0059] The second adsorbent 220 is a device capable of adsorbing and desorbing CO2. The second adsorbent 220 uses a material that adsorbs and desorbs CO2 by pressure fluctuation. The adsorption conditions and desorption conditions for the second adsorbent 220 are set to different pressures.

[0060] Specifically, the amount of CO2 adsorbed by the second adsorbent 220 varies depending on the partial pressure of CO2, and the amount of CO2 adsorbed increases as the partial pressure of CO2 increases. By making the partial pressure of CO2 in the second housing 230 relatively high, it is possible to adsorb CO2 into the second adsorbent 220. In addition, by making the partial pressure of CO2 in the second housing 230 relatively low, it is possible to desorb CO2 from the second adsorbent 220.

[0061] In this embodiment, a metal-organic composite (MOF) is used as the second adsorbent 220. The metal-organic composite is a porous structure in which an organic ligand is coordinately bonded to a metal ion. The metal-organic composite used as the second adsorbent 220 may have any property as long as it has an adsorbing property for CO2. For example, [Cu(4,4'-dihydroxybiphenyl-3-carboxyl)2(4,4'-bipyridyl)] n , [Cu(PF6 - )2(1,2-bis(4-pyridyl)ethane)] n , [Cu(CF3SO3 - )2(1,3-bis(4-pyridyl)propane)2] n , {[Cu(PF6 - )(2,2-bis(4-pyridyl))]PF6 -} n etc. can be mentioned.

[0062] Zeolite or the like may be used as the second adsorbent 220. Zeolite is a microporous crystalline aluminosilicate.

[0063] The second housing 230 accommodates the second adsorbent 220. The second housing 230 is connected to the rear stage of the first housing 120 of the first recovery device 100 via the gas supply unit 210. As a result, the intermediate gas recovered by the first recovery device 100 and pressurized by the gas supply unit 210 is introduced into the second housing 230. The second housing 230 discharges the recovery gas containing CO2 recovered by the second adsorbent 220. The second recovery device 200 recovers CO2 of a second purity that is higher than the first purity of the CO2 recovered by the first recovery device 100.

[0064] The throttle valve 240 has a variable throttle mechanism capable of adjusting the valve opening. The throttle valve 240 can change the gas pressure inside the second adsorbent 220 by adjusting the flow path area. When the gas supply unit 210 pressurizes and supplies the intermediate gas, the throttle valve 240 can be reduced in valve opening to increase the gas pressure inside the second adsorbent 220. On the other hand, the throttle valve 240 can be increased in valve opening to decrease the gas pressure inside the second adsorbent 220.

[0065] 2 shows a specific configuration of the carbon dioxide capture device 1. In addition to the capture devices 100 and 200, the carbon dioxide capture device 1 has a first vacuum pump 310, a second vacuum pump 320, and a control device 400.

[0066] The first collector 100 and the first vacuum pump 310 constitute an electric field type CO2 capture system. The second collector 200 and the second vacuum pump 320 constitute a pressure type CO2 capture system.

[0067] A first inlet pipe 500 for introducing a CO2-containing gas such as exhaust gas or air into the first case 120 and one end of a first connection pipe 501 for discharging an intermediate gas containing CO2 collected by the first collection device 100 are connected to the first case 120 of the first recovery device 100. A first inlet valve 600 is provided on the first inlet pipe 500.

[0068] For example, the first inlet pipe 500 is a pipe for removing soot and NO x The CO2-containing gas from which impurities such as CO2, etc. have been removed in advance may be introduced. In addition, the first introduction pipe 500 may be provided with a blower fan or a blower pump for flowing the CO2-containing gas.

[0069] The other end of the first connection pipe 501 is connected to the gas supply unit 210 of the second recovery unit 200. One end of a first exhaust pipe 502 is connected to the first connection pipe 501. A first exhaust valve 601 is provided on the first exhaust pipe 502. The other end of the first exhaust pipe 502 is connected to the atmosphere.

[0070] The first vacuum pump 310 is provided in the first connection pipe 501 downstream of a first connection part 503 between the first connection pipe 501 and the first exhaust pipe 502. The first vacuum pump 310 scavenges the inside of the first housing 120 by generating a gas flow in the first connection pipe 501.

[0071] In addition, the first vacuum pump 310 is connected to a first exhaust pipe 502. This allows the first vacuum pump 310 to exhaust the sucked gas to the atmosphere via the first exhaust pipe 502. The first vacuum pump 310 is a dry type pump or an oil type pump.

[0072] The first connection pipe 501 is provided with a first connection valve 602 and a second connection valve 603. The first connection valve 602 is provided between the first connection part 503 and the first vacuum pump 310. The second connection valve 603 is provided between the first vacuum pump 310 and the gas supply part 210 of the second recovery device 200. By closing the first introduction valve 600, the first exhaust valve 601, and the first connection valve 602, it is possible to hermetically seal the first housing 120.

[0073] One end of a second connection pipe 504 that discharges the captured gas containing CO2 captured by the second adsorbent 220 is connected to the throttle valve 240 of the second recovery device 200. One end of a second exhaust pipe 505 is connected to the second connection pipe 504. A second exhaust valve 604 is provided on the second exhaust pipe 505. The other end of the second exhaust pipe 505 is connected to the atmosphere.

[0074] The second vacuum pump 320 is provided in the second connection pipe 504, downstream of a second connection part 506 between the second connection pipe 504 and the second exhaust pipe 505. The second vacuum pump 320 generates a gas flow in the second connection pipe 504.

[0075] The second vacuum pump 320 is connected to a second exhaust pipe 505. This allows the second vacuum pump 320 to exhaust the sucked gas to the atmosphere via the second exhaust pipe 505. The second vacuum pump 320 is a dry type pump or an oil type pump.

[0076] The other end of the second connection pipe 504 is connected to a utilization device (not shown) for utilizing the CO2 captured by the second recovery device 200. The utilization device is, for example, a tank for storing CO2. Note that the utilization device may be a factory or equipment that utilizes CO2 instead of a tank.

[0077] The second connection pipe 504 is provided with a third connection valve 605 and a fourth connection valve 606. The third connection valve 605 is provided between the second connection part 506 and the second vacuum pump 320. The fourth connection valve 606 is provided between the second vacuum pump 320 and the utilization device. By closing the second connection valve 603, the third connection valve 605, and the second exhaust valve 604, it is possible to hermetically seal the second housing 230.

[0078] The control device 400 controls the voltage applied to the first adsorbent 110 of the first recovery device 100, and the partial pressure of CO2 in the second casing 230 of the second recovery device 200. The control device 400 also controls the opening and closing of the vacuum pumps 310, 320 and the valves 600-606, utilization devices, etc. The control device 400 receives detection signals from pressure sensors for detecting the internal pressures of the casings 120, 230 of the recovery devices 100, 200, and utilizes the signals for control.

[0079] The control device 400 is configured with a known microcomputer and its peripheral circuits, including a CPU, a ROM, a RAM, etc. The control device 400 performs various calculations and processes according to a control program stored in the ROM.

[0080] The carbon dioxide capture device 1 includes a power unit (not shown). The power unit is a power supply device for the carbon dioxide capture device 1. The power unit supplies power to the capture devices 100, 200, the vacuum pumps 310, 320, the valves, and the pressure sensors in accordance with commands from the control device 400. The above is the overall configuration of the carbon dioxide capture device 1.

[0081] Next, there will be described the operation of the carbon dioxide capture device 1. The control device 400 executes an adsorption process, a scavenging process, and a desorption process in each of the capture devices 100, 200 in order to capture CO2 in a utilization device.

[0082] In this embodiment, the gas flows from the first recovery device 100 to the second recovery device 200. Therefore, after the CO2 is recovered in the first recovery device 100, the CO2 is further recovered in the second recovery device 200.

[0083] First, the control device 400 performs an adsorption process in which CO2 is adsorbed to the first adsorbent 110 of the first recovery device 100. For this purpose, the control device 400 controls the first introduction valve 600 and the first exhaust valve 601 to be open, and controls the first connection valve 602 to be closed. As a result, the first recovery device 100 introduces the CO2-containing gas (introduced gas) into the first housing 120. That is, the CO2-containing gas is supplied to the first adsorbent 110.

[0084] The pressure inside the first housing 120 is atmospheric pressure. The temperature inside the first housing 120 is room temperature (RT). The CO2 concentration inside the first housing 120 is the concentration of CO2 contained in the atmosphere or the like. Therefore, the CO2 concentration inside the first housing 120 is lower than the CO2 concentration of the intermediate gas and the recovered gas in the subsequent stage of the first recovery device 100.

[0085] The CO2-containing gas (introduced gas) flowing into the first housing 120 contains various substances other than CO2. Therefore, the flow rate of the gas flowing into the first housing 120 is greater than the flow rate of the intermediate gas and the collected gas in the rear stage of the first recovery device 100. The dew point temperature inside the first housing 120 is affected by gaseous mixtures such as moisture contained in the CO2-containing gas. Therefore, the dew point temperature inside the first housing 120 is higher than the dew point temperature of the intermediate gas and the collected gas in the rear stage of the first recovery device 100.

[0086] Then, the first recovery device 100 adsorbs the CO2 contained in the CO2-containing gas into the first adsorbent 110. Specifically, the control device 400 applies an adsorption potential between the working electrode 111 and the counter electrode 112 of the first adsorbent 110 by controlling the power unit. This allows electron donation by the counter electrode side active material of the counter electrode 112 and electron attraction by the CO2 adsorbent of the working electrode 111 to be realized simultaneously.

[0087] When an adsorption potential is applied to the working electrode 111 and the counter electrode 112, the counter electrode side active material of the counter electrode 112 releases electrons and becomes oxidized, and the electrons are supplied from the counter electrode 112 to the working electrode 111. The CO2 adsorbent of the working electrode 111 receives electrons and becomes reduced.

[0088] The reduced CO2 adsorbent has a high binding strength with CO2 and binds and adsorbs CO2 contained in the air. In this manner, when an adsorption potential is applied between the working electrode 111 and the counter electrode 112, electrons are supplied from the counter electrode 112 to the working electrode 111 of the first adsorbent 110, and the CO2 adsorbent binds with CO2 as the electrons are supplied. Thus, the first recovery device 100 can recover CO2 from the CO2-containing gas.

[0089] The control device 400 terminates the adsorption process based on, for example, a detection result of a CO2 sensor (not shown) provided in the first exhaust pipe 502. The control device 400 may terminate the adsorption process based on a preset adsorption time.

[0090] After the adsorption step, the control device 400 performs a scavenging step of scavenging the inside of the first housing 120 of the first recovery device 100. For this reason, the control device 400 controls the first inlet valve 600, the first outlet valve 601, and the second connection valve 603 to be closed, while the first adsorbent 110 is adsorbing CO2, i.e., while an adsorption potential is being applied to the first adsorbent 110.

[0091] In addition, the control device 400 controls the first connection valve 602 to an open state, and controls the first vacuum pump 310 to an ON state. As a result, the inside of the first housing 120 is purged via the first vacuum pump 310 and the first exhaust pipe 502.

[0092] The pressure of the electrolytic passing gas discharged to the atmosphere through the first vacuum pump 310 and the first exhaust pipe 502 is atmospheric pressure. The temperature of the electrolytic passing gas is room temperature (RT). Since the CO2 in the first housing 120 is adsorbed by the first adsorbent 110, the CO2 concentration of the electrolytic passing gas is almost zero.

[0093] The electric field passing gas does not contain CO2 adsorbed by the first adsorbent 110 or electric field residual gas remaining inside the first housing 120. Therefore, the flow rate of the electric field passing gas is the introduced gas - (electric field adsorption gas + electric field residual gas). The flow rate of the electric field passing gas is less than the flow rate of the introduced gas.

[0094] The electric field passing gas contains gaseous mixtures such as moisture. This is because the first recovery device 100 employs an electric field, and therefore gaseous mixtures such as moisture contained in the CO2-containing gas are not easily adsorbed by the first adsorbent 110. In other words, most of the gaseous mixtures such as moisture contained in the CO2-containing gas can be discharged to the atmosphere in the scavenging process of the first recovery device 100. Therefore, the dew point temperature of the electric field passing gas is higher than the dew point temperature of the intermediate gas and the recovery gas in the latter stage of the first recovery device 100. Note that the dew point temperature is synonymous with humidity. Therefore, it can be said that the humidity of the electric field passing gas is high.

[0095] Then, the pressure inside the first housing 120 drops to a pressure lower than atmospheric pressure by the suction of the first vacuum pump 310. The control device 400 ends the scavenging process when the pressure inside the first housing 120 reaches a predetermined pressure.

[0096] After the scavenging step, the control device 400 performs a desorption step in which the CO2 adsorbed by the first adsorbent 110 is desorbed. For this reason, the control device 400 controls the first inlet valve 600, the first exhaust valve 601, the third connection valve 605, and the fourth connection valve 606 to be closed while the first adsorbent 110 is adsorbing CO2. The control device 400 also controls the first connection valve 602, the second connection valve 603, and the second exhaust valve 604 to be open.

[0097] The control device 400 then controls the power unit to apply a desorption potential to the working electrode 111 and the counter electrode 112 of the first adsorbent 110. This allows electron donation by the CO2 adsorbent of the working electrode 111 and electron attraction by the counter electrode side active material of the counter electrode 112 to be realized simultaneously.

[0098] The CO2 adsorbent of the working electrode 111 releases electrons and becomes oxidized. The CO2 adsorbent loses its bond with CO2, and releases CO2. The counter electrode active material of the counter electrode 112 receives electrons and becomes reduced.

[0099] In this manner, CO2 is desorbed from the first adsorbent 110. The CO2 released into the inside of the first housing 120 is the CO2 captured by the first capture device 100.

[0100] Furthermore, the intermediate gas (electrolytic recovery gas) containing CO 2 desorbed from the first adsorbent 110 flows from the first housing 120 of the first recovery unit 100 toward the second housing 230 of the second recovery unit 200.

[0101] The pressure of the electric field capture gas flowing through the first connection pipe 501 is atmospheric pressure. The temperature of the electric field capture gas is room temperature (RT). The CO2 concentration of the electric field capture gas is medium. For example, the CO2 concentration of the electric field capture gas is 10% or more. If the CO2 concentration is 10% or more, it becomes easier to capture CO2 in the pressure-type second capture device 200, and there is an advantage in that less energy is required for CO2 capture.

[0102] For example, the control device 400 controls the first CO2 capture capacity in the first capture device 100 so that the CO2 concentration of the intermediate gas (electric field capture gas) is 10% or more. The control device 400 adjusts the first capture capacity by detecting the CO2 concentration of the intermediate gas (electric field capture gas) with a CO2 sensor. The control device 400 may adjust the first capture capacity by estimating the CO2 concentration from the gas flow rate, etc.

[0103] The electric field collection gas is composed of the electric field adsorption gas and the electric field residual gas remaining in the first collection vessel 100. Therefore, the flow rate of the electric field collection gas is the electric field adsorption gas + the electric field residual gas. The flow rate of the electric field collection gas is less than the flow rate of the introduced gas.

[0104] The electrolytic recovery gas contains almost no gaseous mixtures such as moisture. Therefore, the dew point temperature of the electrolytic recovery gas is lower than the dew point temperature of the CO2-containing gas and the electrolytic passing gas. For example, the dew point temperature of the electrolytic recovery gas is -20°C or lower.

[0105] Next, the control device 400 performs an adsorption process in which CO2 is adsorbed by the second adsorbent 220 of the second recovery device 200. The second recovery device 200 introduces the intermediate gas from the first connection pipe 501 into the second housing 230. That is, the CO2-containing gas is supplied to the second adsorbent 220.

[0106] Specifically, the control device 400 operates the gas supply unit 210 to pressurize the intermediate gas and supply it to the second adsorbent 220. In addition, the control device 400 reduces the valve opening of the throttle valve 240. As a result, the partial pressure of CO2 inside the second housing 230 becomes a pressure at which the second adsorbent 220 can adsorb CO2.

[0107] Then, the CO2 contained in the intermediate gas is adsorbed by the second adsorbent 220, and the CO2 is separated from the intermediate gas. The pressure-type passing gas that is not adsorbed by the second adsorbent 220 out of the intermediate gas is exhausted from the second housing 230 and released to the atmosphere via the second exhaust pipe 505.

[0108] The pressure of the pressurized passing gas discharged to the atmosphere through the second exhaust pipe 505 is atmospheric pressure. The temperature of the pressurized passing gas is room temperature (RT). Since the CO2 in the second housing 230 is adsorbed by the second adsorbent 220, the CO2 concentration of the pressurized passing gas is almost zero.

[0109] The pressure-type passing gas does not include CO2 adsorbed by the second adsorbent 220 or pressure-type residual gas remaining inside the second housing 230. Therefore, the flow rate of the pressure-type passing gas is electric field recovery gas - (electric field adsorption gas + electric field residual gas). The flow rate of the electric field passing gas is less than the flow rate of the electric field recovery gas.

[0110] The electric field type passing gas already has a low dew point temperature, so the pressure type passing gas also has a low dew point temperature similar to that of the electric field type passing gas.

[0111] In the adsorption process related to the second recovery device 200, as the adsorption of CO2 continues, the CO2 adsorption rate of the second adsorbent 220 gradually decreases. Therefore, at the timing when the adsorption ends, the adsorption process is switched to the desorption process.

[0112] In the desorption step related to the second recovery unit 200, the control device 400 controls the second connection valve 603 and the second exhaust valve 604 to be closed. The control device 400 controls the third connection valve 605 and the fourth connection valve 606 to be open. The control device 400 also controls the second vacuum pump 320 to be ON.

[0113] Then, the control device 400 stops the gas supply unit 210 and increases the valve opening of the throttle valve 240. As a result, the partial pressure of CO2 inside the second housing 230 becomes lower than the partial pressure of CO2 in the adsorption process. Also, the CO2 adsorbed to the second adsorbent 220 is desorbed from the second adsorbent 220. In this way, by changing the partial pressure of CO2 inside the second housing 230, it is possible to switch between adsorption and desorption of CO2 in the second adsorbent 220.

[0114] As the desorption process of the second recovery device 200 continues, the amount of CO2 adsorbed by the second adsorbent 220 decreases, and the amount of CO2 desorbed from the second adsorbent 220 gradually decreases. Therefore, the desorption process ends when the amount of CO2 desorbed from the second adsorbent 220 becomes a predetermined amount or less. The CO2 desorbed by the second adsorbent 220 is stored in the utilization device as a captured gas via the second connection pipe 504.

[0115] The pressure of the recovered gas sent to the utilization device through the second connection pipe 504 is atmospheric pressure. The temperature of the recovered gas is room temperature (RT). Since the recovered gas does not contain pressure-type passing gas, the CO2 concentration of the recovered gas is high.

[0116] The collected gas does not include CO2 adsorbed by the second adsorbent 220 or pressure-type residual gas remaining inside the second housing 230. Therefore, the flow rate of the collected gas is the pressure-type adsorption gas + pressure-type residual gas. The flow rate of the collected gas is less than the flow rate of the electric field-type collected gas and the pressure-type passing gas.

[0117] The electric field recovery gas already has a low dew point temperature, so the dew point temperature of the recovery gas is also as low as the electric field recovery gas dew point temperature.

[0118] As explained above, the carbon dioxide capture device 1 is a device that combines the electric field type, which is advantageous for adsorption at low concentrations of CO2, has a smaller amount of CO2 adsorption per body size than the pressure type, and is more difficult to purify CO2 than the pressure type, with the pressure type, which has a larger amount of CO2 adsorption per body size than the electric field type, is advantageous for purifying CO2 than the electric field type, and is advantageous for adsorbing CO2 at high concentrations. Note that "advantageous" refers to a larger amount of CO2 adsorption per body size and less energy consumption per amount of CO2 captured. Also, "difficult" refers to a smaller amount of CO2 adsorption per body size and more energy consumption per amount of CO2 captured.

[0119] The first recovery device 100 employs an electric field system, which is characterized by being able to adsorb CO2 even when the concentration of CO2 contained in the CO2-containing gas is low. In addition, the electric field system has the characteristic that gaseous mixtures such as moisture contained in the CO2-containing gas are less likely to be adsorbed by the first adsorbent 110. This allows the first recovery device 100 to selectively adsorb CO2 to the first adsorbent 110 rather than gaseous mixtures such as moisture.

[0120] Furthermore, at the stage of CO2 recovery in the first recovery device 100, gaseous mixtures such as moisture can be easily discharged to the atmosphere by scavenging the inside of the first housing 120. Therefore, the energy required for CO2 recovery can be reduced compared to the case where the inside of the first housing 120 is evacuated to a high vacuum.

[0121] Furthermore, in the electric field method, the processes of adsorption → scavenging → desorption are performed in order, so that the intermediate gas is discharged intermittently. For this reason, for example, a surge tank is required to temporarily store CO2. However, in this embodiment, the second recovery device 200 is provided after the first recovery device 100, so the intermediate gas can be sent to the second recovery device 200 without being stored in the surge tank. Since the energy required to temporarily store CO2 in the surge tank is not required, the energy required for CO2 recovery can be reduced.

[0122] On the other hand, the second recovery device 200 employs a pressure system, and is therefore characterized by its strong adsorption power for gaseous mixtures such as moisture in addition to CO2. For this reason, when the second recovery device 200 is used alone to recover CO2, deactivation occurs in which gaseous mixtures such as moisture are adsorbed. However, since the first recovery device 100 is provided in the stage preceding the second recovery device 200, the intermediate gas sent to the second recovery device 200 contains almost no gaseous mixtures such as moisture. Therefore, it is possible to prevent deactivation from occurring in the second recovery device 200.

[0123] The intermediate gas that is the subject of CO2 capture in the second capture device 200 has a sufficiently higher CO2 concentration than the CO2-containing gas. Since the second capture device 200 further captures CO2 from the intermediate gas, high-purity CO2 can be captured. Furthermore, since the first capture device 100 captures CO2 with a relatively high concentration, the energy required for CO2 capture in the second capture device 200 can be reduced.

[0124] Therefore, the carbon dioxide capture device 1 can capture high-purity CO2 with low energy.

[0125] The second recovery device 200 may recover CO2 from the intermediate gas by changing the temperature of the second adsorbent 220 to switch between adsorption and desorption of CO2 in the second adsorbent 220. In this case, the second recovery device 200 is provided with, for example, a temperature adjustment device that adjusts the temperature of the second adsorbent 220. The higher the temperature of the second adsorbent 220, the smaller the amount of CO2 adsorbed in the second adsorbent 220. In contrast, the lower the temperature of the second adsorbent 220, the larger the amount of CO2 adsorbed in the second adsorbent 220. Therefore, the control device 400 controls the temperature adjustment device to cause the second recovery device 200 to recover CO2. The second recovery device 200 may recover CO2 by changing at least one of the partial pressure of CO2 in the second housing 230 and the temperature of the second adsorbent 220.

[0126] Alternatively, the second recovery device 200 may recover the CO2 from the intermediate gas by a pressure-temperature system that switches between adsorption and desorption of CO2 in the second adsorbent 220 by changing both the partial pressure of CO2 in the second housing 230 and the temperature of the second adsorbent 220. In this case, the control device 400 controls the gas supply unit 210 and the throttle valve 240 to adjust the partial pressure of CO2 in the second housing 230, and controls the temperature adjustment device to adjust the temperature of the second adsorbent 220, thereby causing the second recovery device 200 to recover CO2.

[0127] Even when a temperature type or a pressure-temperature type is adopted as the second recovery device 200, there is an advantage in combining it with an electric field type, just like the pressure type.

[0128] Second embodiment In this embodiment, differences from the first embodiment will be mainly described. The control device 400 monitors the first CO2 capture capacity of the first capture device 100 and the second CO2 capture capacity of the second capture device 200. The control device 400 controls the second capture device 200 to increase the second capture capacity of the second capture device 200 in response to a decrease in the first capture capacity of the first capture device 100.

[0129] The first collection capacity of the first collection device 100 varies depending on the environment of the installation location of the first collection device 100, the environment during operation, the accumulated operation time of the first collection device 100, and deterioration over time of the first collection device 100. The second collection capacity of the second collection device 200 varies similarly.

[0130] The control device 400, for example, monitors the amount of charge transfer in the first adsorbent 110 of the first collector 100, and determines the first collection capability of the first collector 100 based on the change in the amount of charge transfer. The amount of charge transfer changes depending on the surrounding environment of the first collector 100, deterioration over time, and the like.

[0131] The control device 400 calculates the amount of charge transfer based on changes in the voltage applied to the first adsorbent 110 and the current flowing through the first adsorbent 110. For example, when the voltage or current of the first adsorbent 110 decreases, the control device 400 determines that the adsorption amount of the first adsorbent 110 has decreased, i.e., the first collection capacity has decreased. The control device 400 determines the second collection capacity of the second collection device 200 in the same manner as the first collection device 100. In this manner, the control device 400 monitors the collection capacity of each of the collection devices 100, 200.

[0132] When the control device 400 determines that the first recovery capacity of the first recovery device 100 has decreased, the second recovery device 200 increases the second recovery capacity. For example, the control device 400 increases the second recovery capacity of the second recovery device 200 by lengthening the adsorption time in the second recovery device 200. This makes it possible to continue recovering high-purity CO2.

[0133] Even if the first collection capacity of the first collector 100 is reduced, the first collection capacity may return to the original capacity due to some influence. For example, the first collection capacity of the first collector 100 may temporarily decrease due to an environmental factor and then return to the original capacity. In this case, the control device 400 may decrease the second collection capacity of the second collector 200. The control device 400 may also determine the collection capacity of each of the collectors 100, 200 based on other parameters instead of the electric charge.

[0134] Third embodiment In this embodiment, the following mainly describes the differences from the first and second embodiments. In this embodiment, the first recovery unit 100 includes a plurality of adsorption towers.

[0135] Specifically, as shown in Fig. 3, the electric field type first recovery device 100 has a first adsorption tower 101 and a second adsorption tower 102. Each of the adsorption towers 101, 102 has the same configuration as the first recovery device 100. That is, each of the adsorption towers 101, 102 has the above-mentioned first housing 120 and first adsorbent 110. Each of the adsorption towers 101, 102 recovers CO2 in the same manner as the above-mentioned first recovery device 100.

[0136] The first inlet pipe 500 branches into a first inlet branch pipe 507 on the first adsorption tower 101 side and a second inlet branch pipe 508 on the second adsorption tower 102 side. The first inlet branch pipe 507 is provided with a first branch valve 607 (V1). The second inlet branch pipe 508 is provided with a second branch valve 608 (V2).

[0137] The first connection pipe 501 on the side of each of the adsorption towers 101 and 102 branches into a first connection branch pipe 509 on the side of the first adsorption tower 101 and a second connection branch pipe 510 on the side of the second adsorption tower 102. One end of a first discharge branch pipe 511 is connected to the first connection branch pipe 509. The other end of the first discharge branch pipe 511 is connected to the atmosphere. A third branch valve 609 (V3) is provided on the first discharge branch pipe 511.

[0138] One end of a second exhaust branch pipe 512 is connected to the second connection branch pipe 510. The other end of the second exhaust branch pipe 512 is connected to the atmosphere. The second exhaust branch pipe 512 is provided with a fourth branch valve 610 (V4).

[0139] A fifth branch valve 611 (V5) is provided in the first connection branch pipe 509 downstream of a first branch portion 513 between the first connection branch pipe 509 and the first discharge branch pipe 511, i.e., on the first vacuum pump 310 side. A sixth branch valve 612 (V6) is provided in the second connection branch pipe 510 downstream of a second branch portion 514 between the second connection branch pipe 510 and the second discharge branch pipe 512, i.e., on the first vacuum pump 310 side. As a result, the adsorption towers 101, 102 are arranged in parallel.

[0140] A third exhaust pipe 515, which is connected to the atmosphere, is connected to the first vacuum pump 310. The third exhaust pipe 515 is provided with a third exhaust valve 613 (V7).

[0141] The configuration downstream of the first vacuum pump 310 is the same as the configuration shown in Fig. 2. That is, a second connection valve 603 (V8) is provided in the first connection pipe 501 between the first vacuum pump 310 and the second recovery unit 200. In addition, a third connection valve 605 (V9) and a fourth connection valve 606 (V12) are provided in the second connection pipe 504. A second discharge valve 604 (V10) is provided in the second discharge pipe 505.

[0142] Furthermore, in this embodiment, one end of the fourth exhaust pipe 516 is connected to the second vacuum pump 320, and the other end of the fourth exhaust pipe 516 is connected to the second exhaust pipe 505. The fourth exhaust pipe 516 is provided with a fourth exhaust valve 614 (V11).

[0143] The controller 400 controls the adsorption towers 101 and 102 of the first recovery unit 100, the second recovery unit 200, the vacuum pumps 310 and 320, and the valves (V1 to V12).

[0144] Next, the operation of the carbon dioxide capture device 1 according to this embodiment will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a diagram showing the timing of each process in each of the capture devices 100, 200. Fig. 5 is a diagram showing the states of each of the adsorption towers 101, 102, each of the vacuum pumps 310, 320, and each of the valves (V1 to V12).

[0145] First, at time point A, the adsorption process of the first adsorption tower 101 and the scavenging process of the second adsorption tower 102 are each started.

[0146] Therefore, the control device 400 controls the first branch valve 607 (V1) and the third branch valve 609 (V3) to be open, and controls the fifth branch valve 611 (V5) to be closed. The control device 400 applies an adsorption potential to the first adsorbent 110 of the first adsorption tower 101. As a result, the CO2-containing gas is supplied to the first adsorption tower 101, and adsorption of CO2 in the first adsorption tower 101 begins.

[0147] The controller 400 also applies an adsorption potential to the second adsorption tower 102. The controller 400 controls the second branch valve 608 (V2), the fourth branch valve 610 (V4), and the second connection valve 603 (V8) to be closed, and controls the sixth branch valve 612 (V6) and the third exhaust valve 613 (V7) to be open. The controller 400 controls the first vacuum pump 310 to be in an operating (on) state. This causes the inside of the second adsorption tower 102 to be purged.

[0148] Furthermore, the control device 400 controls the second vacuum pump 320 to be stopped (off), thereby completing the desorption process of the second recovery device 200. Thus, recovery of CO2 into the utilization device is completed.

[0149] Next, at time point B, the controller 400 ends the scavenging process of the second adsorption tower 102 and starts the desorption process. The controller 400 also starts the adsorption process of the second recovery unit 200. At time point B, the adsorption process of the first adsorption tower 101 continues.

[0150] In order to carry out the desorption step in the second adsorption tower 102, the controller 400 controls the third discharge valve 613 (V7) to a closed state and controls the second connection valve 603 (V8) to an open state. This blocks the third discharge pipe 515 and forms a path connecting the second adsorption tower 102 to the second recovery unit 200 via the second connection branch pipe 510 and the first connection pipe 501.

[0151] In addition, the controller 400 applies a desorption potential to the first adsorbent 110 of the second adsorption tower 102. As a result, the intermediate gas containing CO2 captured in the second adsorption tower 102 flows into the second recovery device 200.

[0152] Furthermore, the control device 400 controls the third connection valve 605 (V9), the fourth exhaust valve 614 (V11), and the fourth connection valve 606 (V12) to be in a closed state, and controls the second exhaust valve 604 (V10) to be in an open state. The control device 400 causes the second adsorbent 220 to adsorb CO2, for example, by increasing the partial pressure of CO2 in the second housing 230. As a result, in the second recovery device 200, CO2 is recovered from the intermediate gas.

[0153] At time point C, the controller 400 terminates the desorption process in the second adsorption tower 102. The controller 400 also terminates the adsorption process in the second recovery unit 200 and starts the desorption process. At time point C, the adsorption process in the first adsorption tower 101 continues.

[0154] To terminate the desorption step in the second adsorption tower 102, the controller 400 stops (turns off) the application of the desorption potential to the first adsorbent 110 in the second adsorption tower 102. The controller 400 controls the sixth branch valve 612 (V6) and the second connection valve 603 (V8) to be in a closed state, and controls the first vacuum pump 310 to be in a stopped (off) state.

[0155] In addition, the control device 400 controls the second exhaust valve 604 (V10) to be in a closed state in order to end the adsorption process in the second recovery device 200 and start the desorption process. The control device 400 controls the third connection valve 605 (V9) and the fourth connection valve 606 (V12) to be in an open state. The control device 400 controls the second vacuum pump 320 to be in an operating (on) state.

[0156] Furthermore, the control device 400 controls the partial pressure of CO2 inside the second housing 230 to be lower than the partial pressure of CO2 in the adsorption process. As a result, CO2 is desorbed from the second adsorbent 220, and the captured gas containing CO2 is sent to the utilization device.

[0157] Here, as shown in (*1) of Fig. 5, at the timing of time point C, the control device 400 may control the fourth exhaust valve 614 (V11) to an open state for a predetermined time and then to a closed state. Also, as shown in (*2) of Fig. 5, at the timing of time point C, the control device 400 may control the fourth connection valve 606 (V12) to a closed state and then to an open state. This makes it possible to remove other gases such as N2 remaining in the second housing 230 at the beginning of the desorption process of the second recovery device 200, thereby further increasing the purity of CO2.

[0158] At time point D, the controller 400 ends the adsorption process in the first adsorption tower 101 and starts the scavenging process. The controller 400 starts the adsorption process in the second adsorption tower 102.

[0159] To start the scavenging process of the first adsorption tower 101, the controller 400 controls the first branch valve 607 (V1) and the third branch valve 609 (V3) to be closed, and controls the fifth branch valve 611 (V5) to be open. The controller 400 controls the first vacuum pump 310 to be in an operating (on) state. This causes the inside of the first adsorption tower 101 to be scavenged.

[0160] In addition, the control device 400 controls the second branch valve 608 (V2), the fourth branch valve 610 (V4), and the third exhaust valve 613 (V7) to be open in order to start the adsorption process of the second adsorption tower 102. The control device 400 controls the sixth branch valve 612 (V6) and the second connection valve 603 (V8) to be closed. The control device 400 applies an adsorption potential to the first adsorbent 110 of the second adsorption tower 102. As a result, the CO2-containing gas is supplied to the second adsorption tower 102, and the adsorption of CO2 in the second adsorption tower 102 begins.

[0161] The control device 400 controls the second vacuum pump 320 to be stopped (off), thereby completing the desorption process of the second recovery device 200. This completes the recovery of CO2 into the utilization device.

[0162] At time point E, the controller 400 ends the scavenging process in the first adsorption tower 101 and starts the desorption process. The controller 400 also starts the adsorption process in the second recovery unit 200. At time point E, the adsorption process in the second adsorption tower 102 continues.

[0163] The controller 400 controls the third discharge valve 613 (V7) to a closed state and the second connection valve 603 (V8) to an open state in order to carry out the desorption step in the first adsorption tower 101. As a result, the third discharge pipe 515 is blocked and a path connecting the first adsorption tower 101 to the second recovery unit 200 via the first connection branch pipe 509 and the first connection pipe 501 is formed.

[0164] In addition, the control device 400 applies a desorption potential to the first adsorbent 110 of the first adsorption tower 101. As a result, the intermediate gas containing CO2 captured in the first adsorption tower 101 flows into the second recovery device 200. In the second recovery device 200, CO2 is recovered from the intermediate gas.

[0165] To start the adsorption process of the second recovery unit 200, the control device 400 controls the third connection valve 605 (V9), the fourth exhaust valve 614 (V11), and the fourth connection valve 606 (V12) to be closed. The control device 400 controls the second exhaust valve 604 (V10) to be open. As a result, the control device 400 causes the second adsorbent 220 to adsorb CO2, similar to time point B.

[0166] At time F, the controller 400 terminates the desorption step in the first adsorption tower 101. The controller 400 also terminates the adsorption step in the second recovery unit 200 and starts the desorption step. At time F, the adsorption step in the second adsorption tower 102 continues.

[0167] To terminate the desorption step in the first adsorption tower 101, the controller 400 stops (turns off) the application of the desorption potential to the first adsorbent 110 in the first adsorption tower 101. The controller 400 controls the fifth branch valve 611 (V5) and the second connection valve 603 (V8) to be in a closed state, and controls the first vacuum pump 310 to be in a stopped (off) state.

[0168] In addition, the control device 400 controls the third connection valve 605 (V9) and the fourth connection valve 606 (V12) to be open in order to end the adsorption process of the second recovery device 200 and start the desorption process. The control device 400 controls the second exhaust valve 604 (V10) and the fourth exhaust valve 614 (V11) to be closed. The control device 400 controls the second vacuum pump 320 to be in operation (on). Then, the control device 400 desorbs CO2 from the second adsorbent 220 as at time C, and sends the recovered gas to the utilization device.

[0169] In addition, the control device 400 may control the fourth exhaust valve 614 (V11) and the fourth connection valve 606 (V12) to remove other gases remaining in the second housing 230 at the initial stage of the desorption process, as at time point C.

[0170] After that, the process returns to time point A and repeats the above steps. As described above, in this embodiment, the first recovery device 100 has two adsorption towers 101, 102. This allows CO2 to be captured alternately in each of the adsorption towers 101, 102 by adsorbing CO2 in one of the adsorption towers 101, 102 while the other desorbs CO2.

[0171] In addition, since the adsorption towers 101, 102 desorb CO2 at different times, even if the second recovery unit 200 is a single tower, it is possible to recover CO2 from each of the adsorption towers 101, 102. In other words, there is no need to prepare multiple second recovery units 200.

[0172] Here, in this embodiment, two adsorption towers 101, 102 are operated in the first recovery unit 100. However, the two adsorption towers 101, 102 can be operated with less energy than in the case where a surge tank is provided to temporarily store the CO2 captured in the first recovery unit 100. Therefore, using multiple adsorption towers 101, 102 does not increase energy consumption.

[0173] It should be noted that the first recovery vessel 100 is not limited to the two adsorption towers 101 and 102. The first recovery vessel 100 may include three or more adsorption towers.

[0174] (Fourth embodiment) In this embodiment, differences from the third embodiment will be mainly described. As shown in Fig. 6, the carbon dioxide capture device 1 includes a shared vacuum pump 330. The shared vacuum pump 330 is a pump shared by the first capture device 100 and the second capture device 200.

[0175] The shared vacuum pump 330 is provided on the first connection pipe 501. One end of the second connection pipe 504 is connected to the second recovery device 200, and the other end of the second connection pipe 504 is connected between the shared vacuum pump 330 and a branched portion of the first connection pipe 501, where a first connection branch pipe 509 and a second connection branch pipe 510 branch off from each other.

[0176] The fourth exhaust pipe 516 is connected to the third exhaust pipe 515 between the shared vacuum pump 330 and the third exhaust valve 613 (V7). One end of the third connection pipe 517 is connected to the first connection pipe 501 between the shared vacuum pump 330 and the second connection valve 603 (V8). The other end of the third connection pipe 517 is connected to the utilization device. The fourth connection valve 606 (V12) is provided on the third connection pipe 517.

[0177] In the above configuration, the control device 400 controls each valve (V1 to V12) to each state shown in FIG. 5. The control device 400 controls the common vacuum pump 330 to be in an operating (on) state at each time point A to F shown in FIG. 4. As a result, the common vacuum pump 330 operates so as not to overlap each of the following processes: a scavenging process for scavenging the inside of the first housing 120 in a state in which CO2 is adsorbed by the first adsorbent 110 of the first recovery device 100, a desorption process for recovering the CO2 adsorbed by the first adsorbent 110 of the first recovery device 100 after the scavenging process, and a desorption process for recovering the CO2 adsorbed by the second adsorbent 220 of the second recovery device 200. For example, as shown in FIG. 4, the common vacuum pump 330 operates so as not to overlap each of the periods from time point A to time point B, from time point B to time point C, from time point C to time point D, from time point D to time point E, from time point E to time point F, and from time point F to time point A.

[0178] In this way, by shifting the drive timing of the shared vacuum pump 330 between the electric field type first recovery device 100 and the pressure type second recovery device 200, it becomes possible to share the shared vacuum pump 330. Therefore, the configuration of the carbon dioxide recovery device 1 can be simplified.

[0179] (Other embodiments) The configuration of the carbon dioxide capture device 1 shown in each of the above embodiments is an example, and the present invention is not limited to the above-described configuration, and other configurations that can realize the present invention may be used. For example, the CO2-containing gas is not limited to the atmosphere, and any gas containing CO2 may be used.

[0180] The technical features of the carbon dioxide capture device disclosed in this specification are as follows: (Item 1) A carbon dioxide recovery apparatus for recovering CO2 from a CO2-containing gas in two stages, that is, in a first recovery vessel (100) and a second recovery vessel (200), The first recovery device has a larger CO2 adsorption amount per body size at a first CO2 concentration than the second recovery device and consumes less energy per CO2 recovery amount than the second recovery device, and recovers the CO2 of a first purity; A second recovery device that recovers the CO2 at a second CO2 concentration higher than the first CO2 concentration, has a larger CO2 adsorption amount per body size than the first recovery device, consumes less energy per CO2 recovery amount than the first recovery device, and recovers the CO2 at a second purity higher than the first purity; It is composed of The first recovery device includes a first adsorbent (110) and a first housing (120) configured to adsorb and desorb the CO2 contained in the CO2-containing gas, The second recovery unit is connected to the rear of the first housing of the first recovery unit, and an intermediate gas containing the CO2 recovered in the first recovery unit is introduced from the first housing, and the carbon dioxide recovery device has a second adsorbent (220) and a second housing (230) configured to adsorb and desorb the CO2 contained in the intermediate gas. (Item 2) A carbon dioxide capture device for capturing CO2 from a CO2-containing gas, comprising: a first recovery device (100) that recovers the CO2 by an electric field type that switches between adsorption and desorption of the CO2 in the first adsorbent by an electrochemical reaction, the first recovery device (100) having a first adsorbent (110) capable of adsorbing and desorbing the CO2 and a first housing (120) that accommodates the first adsorbent; a second recovery device (200) that has a second adsorbent (220) capable of adsorbing and desorbing the CO2 and a second housing (230) that houses the second adsorbent, and that recovers the CO2 by a method different from that of the first recovery device by switching between adsorption and desorption of the CO2 in the second adsorbent by changing at least one of the partial pressure of the CO2 in the second housing and the temperature of the second adsorbent; Including, The first recovery device introduces the CO2-containing gas into the first housing, adsorbs the CO2 contained in the CO2-containing gas to the first adsorbent, scavenges the inside of the first housing, and then desorbs the CO2 from the first adsorbent to recover the CO2; The second housing of the second recovery device is connected to a rear stage of the first housing of the first recovery device, and the intermediate gas containing the CO2 recovered in the first recovery device is introduced from the first housing, The second recovery device is a carbon dioxide recovery device that recovers the CO2 by adsorbing the CO2 contained in the intermediate gas onto the second adsorbent and desorbing the CO2 from the second adsorbent. (Item 3) 3. The carbon dioxide recovery apparatus according to item 1 or 2, wherein the second recovery device recovers the CO2 from the intermediate gas by a pressure system that switches between adsorption and desorption of the CO2 in the second adsorbent by changing a partial pressure of the CO2 in the second housing. (Item 4) 3. The carbon dioxide recovery apparatus according to item 1 or 2, wherein the second recovery device recovers the CO2 from the intermediate gas using a temperature system that switches between adsorption and desorption of the CO2 in the second adsorbent by changing a temperature of the second adsorbent. (Item 5) 3. The carbon dioxide recovery apparatus according to item 1 or 2, wherein the second recovery device recovers the CO2 from the intermediate gas using a pressure-temperature system that switches between adsorption and desorption of the CO2 in the second adsorbent by changing both a partial pressure of the CO2 in the second housing and a temperature of the second adsorbent. (Item 6) a shared vacuum pump (330) shared by the first recovery vessel and the second recovery vessel; 6. The carbon dioxide capture device according to any one of items 1 to 5, wherein the shared vacuum pump operates in a manner that does not overlap with each of the steps of scavenging the inside of the first housing while the CO2 is adsorbed by the first adsorbent of the first capture device, capturing the CO2 adsorbed by the first adsorbent of the first capture device after the scavenging step, and capturing the CO2 adsorbed by the second adsorbent of the second capture device. (Item 7) 7. The carbon dioxide capture device according to any one of items 1 to 6, further comprising a control device (400) that monitors a first CO2 capture capacity in the first capture device and a second CO2 capture capacity in the second capture device, and controls the second capture device to change the second capture capacity of the second capture device in response to a change in the first capture capacity of the first capture device. [Explanation of symbols]

[0181] 100 First Retriever 110 1st adsorbent 120 1st cabinet 200 Second Retriever 220 Second adsorbent 230 2nd cabinet

Claims

1. CO ２ CO containing ２ The CO ２ A carbon dioxide recovery apparatus that recovers carbon dioxide in two stages, a first recovery device (100) and a second recovery device (200), 1st CO ２ The CO per unit mass at concentration ２ The amount of adsorption of CO is larger than that of the second recovery vessel, and ２ The CO 2 recovery device has a first purity and consumes less energy per recovery amount than the second recovery device. ２ The first collector for collecting the The first CO ２ The second CO ２ The CO per unit mass at concentration ２ The amount of adsorption of CO is larger than that of the first recovery vessel, and ２ The CO 2 having a second purity higher than the first purity and consuming less energy per recovery amount than the first recovery device. ２ The second collector for collecting the It is composed of The first recovery vessel ２ The CO contained in the gas ２ The present invention has a first adsorbent (110) and a first housing (120) configured to be able to adsorb and desorb The second recovery unit is connected to a rear stage of the first housing of the first recovery unit, and the CO recovered by the first recovery unit is ２ An intermediate gas containing ２ The carbon dioxide recovery device has a second adsorbent (220) and a second housing (230) configured to be able to adsorb and desorb.

2. CO ２ CO containing ２ The CO ２ A carbon dioxide capture device for capturing The CO ２ The present invention relates to a method for producing a gas-liquid-phase adsorbent, comprising: a first adsorbent (110) capable of adsorbing and desorbing CO; and a first housing (120) for accommodating the first adsorbent; ２ The CO ２ A first collector (100) for collecting the The CO ２ and a second housing (230) that houses the second adsorbent, and ２ and the temperature of the second adsorbent, ２ By switching between adsorption and desorption of CO, the CO ２ A second collector (200) for collecting the Including, The first recovery vessel ２ A gas containing the CO is introduced into the first housing. ２ The CO contained in the gas ２ is adsorbed in the first adsorbent, and the inside of the first housing is scavenged, and then the CO is removed from the first adsorbent. ２ By desorbing CO ２ Collect the The second housing of the second recovery unit is connected to a rear stage of the first housing of the first recovery unit, and the CO recovered in the first recovery unit is ２ An intermediate gas containing The second recovery device recovers the CO ２ is adsorbed in the second adsorbent, and the CO is removed from the second adsorbent. ２ By desorbing CO ２ A carbon dioxide capture device that captures carbon dioxide.

3. The second recovery unit is configured to recover the CO ２ The partial pressure of the CO ２ The CO is adsorbed from the intermediate gas by a pressure system that switches between adsorption and desorption of ２ The carbon dioxide recovery device according to claim 1 or 2, which recovers

4. The second recovery device changes the temperature of the second adsorbent to reduce the amount of CO ２ The CO is adsorbed from the intermediate gas by a temperature equation that switches between adsorption and desorption of ２ The carbon dioxide recovery device according to claim 1 or 2, which recovers

5. The second recovery unit is configured to recover the CO ２ The partial pressure of the CO in the second adsorbent is changed by changing both the partial pressure of the CO ２ The CO is adsorbed from the intermediate gas by a pressure-temperature system that switches between adsorption and desorption of ２ The carbon dioxide recovery device according to claim 1 or 2, which recovers

6. A shared vacuum pump (330) shared by the first recovery vessel and the second recovery vessel, The common vacuum pump is configured to pump the CO ２ a step of scavenging the inside of the first housing in a state in which the CO is adsorbed in the first adsorbent of the first recovery device after the scavenging step; ２ and recovering the CO adsorbed in the second adsorbent of the second recovery vessel. ２ The carbon dioxide recovery device according to claim 1 or 2, wherein the steps of recovering the first and second carbon dioxide gases are operated so as not to overlap with each other.

7. The CO in the first collector ２ and the first recovery capacity of the second recovery vessel. ２ and a control device (400) that monitors the first capture capacity of the first capture device and the second capture capacity of the second capture device so as to change the second capture capacity of the second capture device in response to a change in the first capture capacity of the first capture device.

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