Gas Recovery System

Abstract

To provide a gas recovery system that can be improved in a performance in an adsorbing gas to be recovered.SOLUTION: A gas recovery system, which is configured to recover carbon dioxide from a mixed gas containing carbon dioxide by electrochemical reaction, comprises a carbon dioxide recovery device 10 into which the mixed gas is introduced, and an electrochemical cell 101, arranged in the carbon dioxide recovery device 10, which has a work electrode 104 including an adsorbent that can adsorb carbon dioxide and a counter electrode 106. When a voltage is applied to a space between the work electrode 104 and the counter electrode 106, an electron is supplied from the counter electrode 106 to the work electrode 104, so that the adsorbent binds to a gas to be recovered accompanying supply of the electron thereto. The electrochemical cell 101 is arranged to contact carbon dioxide, and a convex part 22 having a wall surface 21 opposing to a flowing direction of the carbon dioxide is formed on a contact surface 20 contacting the carbon dioxide in the electrochemical cell 101.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a gas recovery system that recovers a target gas from a mixed gas containing the target gas. [Background technology]

[0002] Patent Document 1 proposes a gas recovery system that separates carbon dioxide, which is a target gas to be recovered, from a mixed gas containing carbon dioxide by an electrochemical reaction. In the gas recovery system of Patent Document 1, a carbon dioxide adsorbent capable of adsorbing carbon dioxide is provided on the working electrode of an electrochemical cell. The carbon dioxide adsorbent is an electroactive species, and by changing the potential difference between the working electrode and the counter electrode, it is possible to switch between adsorption and release of carbon dioxide by the carbon dioxide adsorbent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-533470 Summary of the Invention [Problem to be solved by the invention]

[0004] In the gas recovery system of Patent Document 1, a mixed gas is caused to flow over the surface of a carbon dioxide adsorbent formed in a plate shape, and carbon dioxide contained in the mixed gas is adsorbed by the adsorbent. Therefore, if gas diffusion on the surface of the carbon dioxide adsorbent is insufficient, the uptake of carbon dioxide into the carbon dioxide adsorbent is suppressed, resulting in a decrease in adsorption performance.

[0005] Furthermore, if the pressure loss of the mixed gas flowing over the surface of the carbon dioxide adsorbent is large, gas exchange before and after adsorption of carbon dioxide is suppressed, which may result in a decrease in adsorption performance.

[0006] In view of the above, an object of the present invention is to provide a gas recovery system capable of improving the adsorption performance of a gas to be recovered. [Means for solving the problem]

[0007] In order to achieve the above object, the gas recovery system according to claim 1 is a gas recovery system that recovers a target gas from a mixed gas containing the target gas by electrochemical reaction, comprising: a recovery section (10) into which the mixed gas is introduced; an electrochemical cell (101) disposed in the recovery section and having a working electrode (104) containing an adsorbent capable of adsorbing the gas to be recovered and a counter electrode (106); When a voltage is applied between the working electrode and the counter electrode, electrons are supplied from the counter electrode to the working electrode, and the adsorbent bonds with the gas to be collected as the electrons are supplied to the adsorbent. The electrochemical cell is disposed in contact with the gas to be captured; The contact surface (20) of the electrochemical cell that comes into contact with the target gas has a wall surface (21) that faces the flow direction of the target gas. At the same time, the separation of the main flow of the target gas causes a vortex to form, which promotes the diffusion of the target gas at the contact surface. A wall formation (22) is provided.

[0008] According to this, by providing the wall surface forming portion (22) having the wall surface (21) facing the flow direction of the gas to be collected, a vortex caused by separation of the main flow of the gas to be collected can be formed by the wall surface forming portion (22). As a result, the diffusion of the gas to be collected can be promoted on the contact surface (20) that comes into contact with the gas to be collected, thereby improving the adsorption performance of the gas to be collected.

[0009] 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]

[0010] [Figure 1] 1 is a conceptual diagram showing an overall configuration of a carbon dioxide capture system according to a first embodiment. [Diagram 2] FIG. 1 is a perspective view showing a carbon dioxide capture device in a first embodiment. [Diagram 3] FIG. 2 is a perspective view showing a state in which a plurality of electrochemical cells are stacked in the first embodiment. [Figure 4] FIG. 1 is a perspective view showing an electrochemical cell in a first embodiment. [Diagram 5] FIG. 5 is an enlarged view of part V in FIG. [Figure 6] 6 is a cross-sectional view taken along line VI-VI of FIG. 5. [Figure 7] FIG. 11 is a perspective view showing a carbon dioxide capture device in a second embodiment. [Figure 8] FIG. 11 is a plan view of a contact surface of an electrochemical cell according to a second embodiment, as viewed from the cell stacking direction. [Figure 9] FIG. 11 is a perspective view showing a contact surface of an electrochemical cell in a second embodiment. [Figure 10] FIG. 11 is a plan view of a contact surface of an electrochemical cell according to a third embodiment, as viewed from the cell stacking direction. [Figure 11] FIG. 11 is a perspective view showing a contact surface of an electrochemical cell in a third embodiment. [Figure 12] FIG. 11 is a cross-sectional view showing a contact surface of an electrochemical cell in a fourth embodiment. [Figure 13] FIG. 13 is a perspective view showing a contact surface of an electrochemical cell in a fifth embodiment. [Figure 14] FIG. 13 is a plan view of a part of a contact surface of an electrochemical cell in a sixth embodiment, as viewed from the cell stacking direction. [Figure 15] FIG. 13 is a perspective view showing a contact surface of an electrochemical cell in a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

[0012] A first embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the gas recovery system of the present invention is applied to a carbon dioxide recovery system 1 that recovers carbon dioxide from a mixed gas containing carbon dioxide. In other words, the target gas to be recovered by the gas recovery system is carbon dioxide.

[0013] As shown in FIG. 1, the carbon dioxide capture system 1 of this embodiment includes a carbon dioxide capture device 10, a pump 11, a flow path switching valve 12, a carbon dioxide utilization device 13, and a control device 14.

[0014] The carbon dioxide capture device 10 is a capture section that separates and captures carbon dioxide from a mixed gas. The mixed gas may be, for example, the atmosphere or exhaust gas from an internal combustion engine. The mixed gas also contains gases other than carbon dioxide. The carbon dioxide capture device 10 is supplied with the mixed gas and discharges a carbon dioxide removed gas after carbon dioxide has been captured from the mixed gas, or the carbon dioxide captured from the mixed gas. The configuration of the carbon dioxide capture device 10 will be described in detail later.

[0015] The pump 11 supplies the mixed gas to the carbon dioxide capture apparatus 10, and discharges carbon dioxide or a carbon dioxide-removed gas from the carbon dioxide capture apparatus 10. In the example shown in Fig. 1, the pump 11 is provided on the downstream side of the carbon dioxide capture apparatus 10 in the gas flow direction, but the pump 11 may also be provided on the upstream side of the carbon dioxide capture apparatus 10 in the gas flow direction.

[0016] The flow path switching valve 12 is a three-way valve that switches the flow path of the exhaust gas from the carbon dioxide capture device 10. When carbon dioxide removed gas is discharged from the carbon dioxide capture device 10, the flow path switching valve 12 switches the flow path of the exhaust gas to the atmosphere side, and when carbon dioxide is discharged from the carbon dioxide capture device 10, the flow path switching valve 12 switches the flow path of the exhaust gas to the carbon dioxide utilization device 13 side.

[0017] The carbon dioxide utilization device 13 is a device that utilizes carbon dioxide. For example, a storage tank that stores carbon dioxide or a conversion device that converts carbon dioxide into fuel can be used as the carbon dioxide utilization device 13. The conversion device can be a device that converts carbon dioxide into a hydrocarbon fuel such as methane. The hydrocarbon fuel may be a gas fuel at normal temperature and pressure, or a liquid fuel at normal temperature and pressure.

[0018] The control device 14 is composed of a well-known microcomputer including a CPU, ROM, RAM, etc., and its peripheral circuits. The control device 14 performs various calculations and processing based on a control program stored in the ROM, and controls the operation of various controlled devices. The control device 14 of this embodiment controls the operation of the carbon dioxide capture device 10, the operation of the pump 11, and the flow path switching control of the flow path switching valve 12, etc.

[0019] Next, the carbon dioxide capture device 10 of this embodiment will be described with reference to Figures 2 to 4. In Figures 2 to 4, the direction from the front of the paper to the back of the paper is the gas flow direction, and the vertical direction of the paper is the cell stacking direction.

[0020] As shown in Fig. 2, the carbon dioxide capture device 10 includes a storage unit 100. The storage unit 100 is formed in a box shape and can be made of, for example, a metal material. An electrochemical cell 101 is stored in the storage unit 100. The carbon dioxide capture device 10 adsorbs and desorbs carbon dioxide by an electrochemical reaction in the electrochemical cell 101, and separates and captures the carbon dioxide from the mixed gas.

[0021] The storage unit 100 has two openings. These two openings are an inlet 100a that introduces the mixed gas into the interior, and an outlet (not shown) that discharges the carbon dioxide removal gas and carbon dioxide from the interior. The inlet 100a introduces the mixed gas into the carbon dioxide capture device 10 from one direction. The gas flow direction is the flow direction when the mixed gas passes through the storage unit 100, and is the direction from the inlet 100a of the storage unit 100 toward the outlet.

[0022] In Fig. 2, the mixed gas flows from the front side of the paper to the back side of the paper. Therefore, the front side of the container 100 in the figure is the inlet part 100a, and the back side of the figure is the outlet part. Note that the inlet part 100a and the outlet part of the container 100 may be provided with opening and closing members for opening and closing them, respectively.

[0023] 2, a plurality of electrochemical cells 101 are stacked and arranged inside the storage unit 100. The cell stacking direction in which the plurality of electrochemical cells 101 are stacked is perpendicular to the gas flow direction. Each electrochemical cell 101 is configured in a plate shape and arranged so that the plate surface intersects with the cell stacking direction.

[0024] Fig. 3 shows a state in which a plurality of electrochemical cells 101 are stacked. Fig. 4 shows one electrochemical cell 101. In Fig. 4, the components of the electrochemical cell 101, such as the working electrode current collecting layer 103, are illustrated with a gap between each other, but in reality, these components are stacked and arranged so as to be in contact with each other.

[0025] 3, a predetermined gap is provided between adjacent electrochemical cells 101. The gap provided between adjacent electrochemical cells 101 constitutes a gas flow path 102 through which a mixed gas flows.

[0026] 3 and 4, the electrochemical cell 101 includes a working electrode current collecting layer 103, a working electrode 104, a counter electrode current collecting layer 105, a counter electrode 106, and a separator 107. In adjacent electrochemical cells 101, the working electrode current collecting layer 103 of one side faces the counter electrode current collecting layer 105 of the other side, with a gas flow path 102 in between. As shown in FIG. 4, the electrochemical cell 101 includes an electrolyte 108 provided across the working electrode 104, the counter electrode 106, and the separator 107.

[0027] The working electrode current collecting layer 103, the working electrode 104, the counter electrode current collecting layer 105, the counter electrode 106, and the separator 107 are each formed in a plate shape. The electrochemical cell 101 is formed as a laminate in which the working electrode current collecting layer 103, the working electrode 104, the counter electrode current collecting layer 105, the counter electrode 106, and the separator 107 are laminated. The direction in which the working electrode current collecting layers 103 and the like of each electrochemical cell 101 are laminated is the same as the cell stacking direction in which the multiple electrochemical cells 101 are stacked.

[0028] The working electrode current collecting layer 103 is a porous conductive material having pores through which a mixed gas containing carbon dioxide can pass. As the working electrode current collecting layer 103, any material may be used as long as it has gas permeability and conductivity, and for example, a metal material or a carbonaceous material may be used. In this embodiment, a metal porous body is used as the working electrode current collecting layer 103.

[0029] The working electrode 104 contains a carbon dioxide adsorbent, a conductive material, and a binder. The carbon dioxide adsorbent, the conductive material, and the binder are used in a state of a mixture.

[0030] The carbon dioxide adsorbent is configured to be capable of adsorbing carbon dioxide. The carbon dioxide adsorbent adsorbs carbon dioxide by receiving electrons and desorbs the adsorbed carbon dioxide by releasing electrons. For example, polyanthraquinone can be used as the carbon dioxide adsorbent.

[0031] The conductive material forms a conductive path to the carbon dioxide adsorbent. Examples of the conductive material that can be used include carbon materials such as carbon nanotubes, carbon black, and graphene.

[0032] The binder is provided to hold the carbon dioxide adsorbent and the conductive material. For example, a conductive resin can be used as the binder. For the conductive resin, an epoxy resin containing Ag or the like as a conductive filler, or a fluororesin such as polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF) can be used.

[0033] The counter electrode current collecting layer 105 is made of a conductive material. For example, a metal material or a carbonaceous material can be used as the counter electrode current collecting layer 105. In this embodiment, a metal plate is used as the counter electrode current collecting layer 105.

[0034] The counter electrode 106 contains an electroactive auxiliary material, a conductive material, and a binder. The conductive material and the binder of the counter electrode 106 have the same configuration as those of the working electrode 104, and therefore a description thereof will be omitted. In this embodiment, the counter electrode 106 is made of a material having an active material that serves as an electron donor.

[0035] The electroactive auxiliary material of the counter electrode 106 is an auxiliary electroactive species that transfers electrons between the counter electrode 106 and the carbon dioxide adsorbent of the working electrode 104. As the electroactive auxiliary material, for example, a metal complex that allows the transfer of 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. These metal complexes may be polymers or monomers.

[0036] The separator 107 is disposed between the working electrode 104 and the counter electrode 106, and separates the working electrode 104 from the counter electrode 106. The separator 107 is an insulating ion-permeable membrane that prevents physical contact between the working electrode 104 and the counter electrode 106 to suppress electrical short circuits and allows ions to pass through. The separator 107 may be a cellulose membrane, a polymer, a composite material of a polymer and ceramic, or the like.

[0037] For example, an ionic liquid can be suitably used as the electrolyte 108. The ionic liquid is a liquid salt that is non-volatile under normal temperature and pressure.

[0038] The electrochemical cell 101 is provided with a power supply 109 connected to a working electrode current collecting layer 103 and a counter electrode current collecting layer 105. The power supply 109 applies a predetermined voltage to the working electrode 104 and the counter electrode 106, and can change the potential difference between the working electrode 104 and the counter electrode 106. The working electrode 104 is a negative electrode, and the counter electrode 106 is a positive electrode.

[0039] By changing the potential difference between the working electrode 104 and the counter electrode 106, the electrochemical cell 101 can be switched between an operation mode in which carbon dioxide is captured by the working electrode 104 and an operation mode in which carbon dioxide is released from the working electrode 104. The carbon dioxide capture mode is a charge mode in which the electrochemical cell 101 is charged, and the carbon dioxide release mode is a discharge mode in which the electrochemical cell 101 is discharged.

[0040] In the carbon dioxide capture mode, a first voltage V1 is applied between the working electrode 104 and the counter electrode 106, and electrons are supplied from the counter electrode 106 to the working electrode 104. At the first voltage V1, the working electrode potential is less than the counter electrode potential. The first voltage V1 can be set within a range of, for example, 0.5 to 2.0 V. In the carbon dioxide capture mode, electrons are supplied from the counter electrode 106 to the working electrode 104, and the carbon dioxide adsorbent bonds with carbon dioxide as the electrons are supplied.

[0041] In the carbon dioxide release mode, a second voltage V2 is applied between the working electrode 104 and the counter electrode 106, and electrons are supplied from the working electrode 104 to the counter electrode 106. The second voltage V2 is a voltage different from the first voltage V1. The second voltage V2 may be any voltage lower than the first voltage V1, and the magnitude relationship between the working electrode potential and the counter electrode potential is not limited. That is, in the carbon dioxide release mode, the working electrode potential may be less than the counter electrode potential, the working electrode potential may be equal to the counter electrode potential, or the working electrode potential may be greater than the counter electrode potential.

[0042] 5 and 6, the surface of the working electrode current collecting layer 103 is configured as a contact surface 20 that comes into contact with the mixed gas. The contact surface 20 is provided with a protrusion 22 that protrudes from the contact surface 20. The protrusion 22 has a wall surface 21 that faces the gas flow direction. Therefore, the protrusion 22 is a wall surface forming portion that forms the wall surface 21.

[0043] In addition, the wall surface 21 facing the gas flow direction means that the wall surface 21 is not parallel to the gas flow direction. In other words, the wall surface 21 is provided so as to intersect with the gas flow direction. In this embodiment, the wall surface 21 is provided so as to be perpendicular to the gas flow direction.

[0044] The protrusions 22 are formed in a shape that extends perpendicular to the flow direction of the mixed gas introduced from the introduction portion 100a. In this embodiment, the protrusions 22 are formed in a quadrangular prism shape that extends in a direction (hereinafter referred to as the extension direction) perpendicular to both the gas flow direction and the cell stacking direction. A plurality of protrusions 22 are arranged in the gas flow direction.

[0045] As described above, in the carbon dioxide capture system 1 of the present embodiment, the protrusions 22 having the wall surfaces 21 facing the gas flow direction are provided on the surface of the working electrode current collecting layer 103 in the electrochemical cell 101. This makes it possible to form vortexes due to separation of the mainstream of the mixed gas on the gas flow downstream side of the protrusions 22. As a result, it is possible to promote diffusion of the mixed gas on the contact surface 20 that comes into contact with the mixed gas, thereby improving the carbon dioxide adsorption performance.

[0046] In this embodiment, the protrusions 22 are formed in a shape that extends perpendicularly to the flow direction of the mixed gas introduced from the introduction part 100a. This can further promote the diffusion of the mixed gas, thereby further improving the carbon dioxide adsorption performance.

[0047] Second embodiment Next, a second embodiment of the present invention will be described with reference to Figures 7 to 9. In this embodiment, the arrangement of the protrusions 22 is changed from that of the first embodiment.

[0048] As shown in FIG. 7, in the carbon dioxide capture system 1 of this embodiment, the carbon dioxide capture device 10 includes a first introduction part 100a, a second introduction part 100b, a third introduction part 100c, and a fourth introduction part 100d for introducing the mixed gas into the storage part 100.

[0049] The first introduction part 100a introduces the mixed gas into the storage part 100 of the carbon dioxide capture device 10 from a first direction. The second introduction part 100b introduces the mixed gas into the storage part 100 from a second direction. The third introduction part 100c introduces the mixed gas into the storage part 100 from a third direction. The fourth introduction part 100d introduces the mixed gas into the storage part 100 from a fourth direction.

[0050] The first to fourth directions are different from each other. The first to fourth directions are each perpendicular to the cell stacking direction. In this embodiment, the second direction is a direction opposite to the first direction. The third and fourth directions are each perpendicular to the first and second directions. The third direction is a direction opposite to the fourth direction.

[0051] 8 and 9, in this embodiment, a first convex portion 22a, a second convex portion 22b, a third convex portion 22c, and a fourth convex portion 22d are provided as the convex portion 22. The first convex portion 22a corresponds to a first wall surface forming portion, and the second convex portion 22b corresponds to a second wall surface forming portion.

[0052] The first protrusion 22a is formed in a shape extending perpendicularly to the first direction. A wall surface 21 (hereinafter referred to as the first wall surface 21a) of the first protrusion 22a is provided so as to come into contact with the mixed gas introduced from the first introduction part 100a. In this embodiment, the first wall surface 21a is provided so as to be perpendicular to the first direction. A plurality of first protrusions 22a are arranged in the first direction.

[0053] The second protrusion 22b is formed in a shape extending perpendicular to the second direction. The wall surface 21 (hereinafter referred to as the second wall surface 21b) of the second protrusion 22b is provided so as to come into contact with the mixed gas introduced from the second introduction part 100b. In this embodiment, the second wall surface 21b is provided so as to be perpendicular to the second direction. A plurality of the second protrusions 22b are arranged in the second direction.

[0054] The third protrusion 22c is formed in a shape extending perpendicular to the third direction. The wall surface 21 (hereinafter referred to as the third wall surface 21c) of the third protrusion 22c is provided so as to come into contact with the mixed gas introduced from the third introduction part 100c. In this embodiment, the third wall surface 21c is provided so as to be perpendicular to the third direction. The third protrusions 22c are arranged in a line in the third direction.

[0055] The fourth protrusion 22d is formed in a shape extending perpendicular to the fourth direction. The wall surface 21 of the fourth protrusion 22d (hereinafter referred to as the fourth wall surface 21d) is provided so as to come into contact with the mixed gas introduced from the fourth introduction part 100d. In this embodiment, the fourth wall surface 21d is provided so as to be perpendicular to the fourth direction. A plurality of the fourth protrusions 22d are arranged in the fourth direction.

[0056] As described above, the carbon dioxide capture system 1 of this embodiment has the first to fourth convex portions 22a to 22d as the convex portion 22. Each of the convex portions 22a to 22d is formed in a shape extending perpendicularly to a corresponding one of the first to fourth directions. This makes it possible to promote the diffusion of the mixed gas introduced from each of the first to fourth introduction portions 100a to 100d by the first to fourth convex portions 22a to 22d. Therefore, even in the carbon dioxide capture system 1 in which the mixed gas is introduced from the multiple introduction portions 100a to 100d, it is possible to reliably improve the carbon dioxide adsorption performance.

[0057] Third embodiment Next, a third embodiment of the present invention will be described with reference to Figures 10 and 11. In this embodiment, the shape of the protrusion 22 is changed from that of the first embodiment.

[0058] 10 and 11, in the carbon dioxide capture system 1 of this embodiment, the convex portion 22 is formed in a circular shape when viewed from the cell stacking direction. Therefore, the wall surface 21 of the convex portion 22 has a curved surface. By providing such a convex portion 22, it is possible to reliably improve the carbon dioxide adsorption performance even in the carbon dioxide capture system 1 into which the mixed gas is introduced from all directions.

[0059] (Fourth embodiment) Next, a fourth embodiment of the present invention will be described with reference to Fig. 12. In this embodiment, the shape of the protrusion 22 is changed from that of the first embodiment.

[0060] 12, in the carbon dioxide capture system 1 of this embodiment, the protrusion 22 is formed into a triangular prism extending in the extension direction. The protrusion 22 has a wall surface 21 and a downstream surface 23 disposed downstream in the gas flow direction from the wall surface 21. An angle θ1 between the wall surface 21 and the gas flow direction is smaller than an angle θ2 between the downstream surface 23 and the gas flow direction.

[0061] According to the carbon dioxide capture system of this embodiment, the pressure loss of the mixed gas flow can be reduced by reducing the angle θ1 between the wall surface 21 and the gas flow direction. As a result, a decrease in the energy efficiency of the pump 11 can be suppressed. In addition, the gas flow toward the contact surface 20 can be secured by increasing the angle θ2 between the downstream surface 23 and the gas flow direction. As a result, the carbon dioxide adsorption performance can be improved.

[0062] Fifth embodiment Next, a fifth embodiment of the present invention will be described with reference to Fig. 13. In this embodiment, the shape of the protrusion 22 is changed from that of the first embodiment.

[0063] 13, in the carbon dioxide capture system 1 of the present embodiment, a plurality of protrusions 22 are provided on the contact surface 20. A plurality of protrusions 22 are arranged side by side in both the gas flow direction and the extension direction.

[0064] The contact surface 20 is provided with protrusions 22 and flat surfaces 201 on which no protrusions 22 are formed. The protrusions 22 and the flat surfaces 201 are alternately arranged in the extension direction. The flat surfaces 201 form gaps (i.e., gas flow paths) through which the mixed gas flows.

[0065] According to the carbon dioxide capture system of this embodiment, since there are portions where the flat portions 201 are arranged in the flow direction of the mixed gas, it is possible to reduce the pressure loss of the mixed gas flow. Meanwhile, in the protruding portions 22, it is possible to promote the diffusion of the mixed gas. Therefore, it is possible to improve the carbon dioxide adsorption performance while reducing the pressure loss of the mixed gas flow.

[0066] Sixth embodiment Next, a sixth embodiment of the present invention will be described with reference to Figures 14 and 15. In this embodiment, the arrangement of the protrusions 22 is changed from that of the fifth embodiment.

[0067] 14 and 15, in the carbon dioxide capture system 1 of the present embodiment, the multiple protrusions 22 are arranged in a staggered pattern. This can eliminate the flow of mixed gas that passes through the protrusions 22 in a straight line, so that the diffusion effect of the mixed gas by the protrusions 22 can be more reliably obtained.

[0068] (Other embodiments) The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. Furthermore, the means disclosed in each of the above-described embodiments may be appropriately combined within the scope of feasibility.

[0069] (1) In the above embodiment, the gas recovery system of the present invention is applied to the carbon dioxide recovery system 1 that recovers carbon dioxide from a mixed gas, but is not limited to this embodiment. The gas recovery system of the present invention may be applied to a configuration that recovers a specific type of gas other than carbon dioxide from a mixed gas.

[0070] (2) In the above-described first to third, fifth and sixth embodiments, the wall surface 21 of the protrusion 22 is provided so as to be perpendicular to the gas flow direction. However, the wall surface 21 does not necessarily have to be perpendicular to the gas flow direction.

[0071] (3) In the above embodiment, the protrusions 22 are provided on the surface of the working electrode current collecting layer 103, but the location of the protrusions 22 is not limited to this. For example, the protrusions 22 may be provided on the surface of the counter electrode current collecting layer 105.

[0072] (4) In the above embodiment, the protrusion 22 protruding from the contact surface 20 is used as the wall surface forming portion, but the wall surface forming portion is not limited to this. For example, a recess formed by recessing a part of the contact surface 20 may be used as the wall surface forming portion, and the wall surface 21 may be formed by the recess.

[0073] (5) In the above-described second embodiment, the first to fourth introduction parts 100a to 100d that introduce the mixed gas from the first to fourth directions into the storage part 100 are provided, and the first to fourth convex parts 22a to 22d formed in shapes extending perpendicularly to the corresponding directions among the first to fourth directions are provided. However, the configurations of the introduction parts 100a to 100d and the convex parts 22a to 22d are not limited to this embodiment.

[0074] For example, first and second introduction parts 100a, 100b for introducing the mixed gas from the first and second directions may be provided to the container 100, and first and second convex parts 22a, 22b may be provided so as to extend perpendicularly to the corresponding directions among the first and second directions. Also, first to third introduction parts 100a-100c for introducing the mixed gas from the first to third directions may be provided to the container 100, and first to third convex parts 22a-22c may be provided so as to extend perpendicularly to the corresponding directions among the first to third directions. Furthermore, first to Nth introduction parts for introducing the mixed gas from the first to Nth directions (N is an integer of 5 or more) may be provided to the container 100, and first to Nth convex parts may be provided so as to extend perpendicularly to the corresponding directions among the first to Nth directions. [Explanation of symbols]

[0075] 20 Contact surface 21 Wall 22 Convex portion (wall surface forming portion)

Claims

1. A gas recovery system that recovers a target gas from a mixed gas containing the target gas by electrochemical reaction, A recovery section (10) into which the mixed gas is introduced; an electrochemical cell (101) disposed in the recovery section and having a working electrode (104) and a counter electrode (106) containing an adsorbent capable of adsorbing the target gas to be recovered; When a voltage is applied between the working electrode and the counter electrode, electrons are supplied from the counter electrode to the working electrode, and the adsorbent is bonded to the gas to be recovered in response to the supply of electrons; The electrochemical cell is disposed so as to be in contact with the gas to be recovered, A gas recovery system in which a contact surface (20) in the electrochemical cell that comes into contact with the gas to be recovered has a wall surface (21) that faces the flow direction of the gas to be recovered, and a wall surface forming section (22) is provided that promotes diffusion of the gas to be recovered at the contact surface by forming a vortex due to separation of the main flow of the gas to be recovered.

2. Further, an introduction part (100a) is provided for introducing the mixed gas into the recovery part from one direction, 2. The gas recovery system according to claim 1, wherein the wall surface forming portion is formed in a shape extending perpendicularly to a flow direction of the mixed gas introduced from the introduction portion.

3. Further, a first introduction part (100a) that introduces the mixed gas from a first direction into the recovery part; A second introduction part (100b) that introduces the mixed gas into the recovery part from a second direction different from the first direction, As the wall surface forming portion, A first wall surface forming portion (22a) formed in a shape extending perpendicular to the first direction; A second wall surface forming portion (22b) formed in a shape extending perpendicular to the second direction is provided, the wall surface of the first wall surface forming portion is provided so as to come into contact with the mixed gas introduced from the first introduction portion, 2. The gas recovery system according to claim 1, wherein the wall surface of the second wall surface forming portion is provided so as to come into contact with the mixed gas introduced from the second introduction portion.

4. The gas recovery system according to claim 1 , wherein the wall surface has a curved surface.

5. The wall surface forming portion has the wall surface and a downstream surface (23) disposed downstream of the wall surface in the flow direction of the mixed gas, 2. The gas recovery system according to claim 1, wherein an angle (θ1) between the wall surface and the flow direction of the mixed gas is smaller than an angle (θ2) between the downstream surface and the flow direction of the mixed gas.

6. 2. The gas recovery system according to claim 1, wherein the contact surface is provided with the wall surface forming portion and a flat portion (201) on which the wall surface forming portion is not formed.

7. The contact surface is provided with a plurality of the wall surface forming portions, The gas recovery system according to claim 6 , wherein the wall surface forming portions are arranged in a staggered pattern.

8. 8. The gas recovery system according to claim 1, wherein the gas to be recovered is carbon dioxide.

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