Gas Recovery System

Abstract

To provide a gas recovery system that comprises a plurality of laminated electrochemical cells and has a gas passage formed between the adjacent electrochemical cells, in which a width of the gas passage is kept uniform.SOLUTION: A gas recovery system, which is configured to recover a gas to be recovered from a mixed gas by electrochemical reaction, comprises a plurality of electrochemical cells 101 which has work electrodes 104 and counter electrodes 106, where the electrochemical cells are laminatingly arranged and a gas flow passage 102 through which the mixed gas flows is formed between the adjacent electrochemical cells. Support parts 110 and 113 are provided between the adjacent electrochemical cells. A predetermined gap is formed by the support part between the adjacent electrochemical cells, where the gap constitutes the gas passage.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a gas recovery system for recovering a specific type of gas from a mixed gas. [Background technology]

[0002] Patent Document 1 proposes a gas recovery system that recovers CO2 from a CO2-containing mixed gas through an electrochemical reaction. The gas recovery system in Patent Document 1 is provided with an electrochemical cell having a working electrode and a counter electrode, and can switch between adsorption and release of CO2 by changing the potential difference between the working electrode and the counter electrode. Patent Document 1 also describes stacking multiple electrochemical cells and providing gas flow paths between the stacked cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2008-528285 Summary of the Invention [Problem to be solved by the invention]

[0004] In a configuration in which multiple electrochemical cells are stacked, narrowing the gap between the stacked electrochemical cells for miniaturization makes it difficult to maintain the width of the gas flow path, which can lead to increased pressure loss at the gas inlet and variations in the width of the gas flow path.

[0005] Furthermore, if the electrochemical cells contain liquid substances (such as CO2 adsorbents or electrolytes), the liquid materials may leak due to their own weight when the electrochemical cells are stacked, which may result in a decrease in gas recovery performance.

[0006] In view of the above, an object of the present invention is to maintain the width of a gas flow path in a gas recovery system including a plurality of stacked electrochemical cells, in which a gas flow path is formed between adjacent electrochemical cells. Another object of the present invention is to suppress leakage of a liquid material when the electrochemical cells contain a liquid material when the electrochemical cells are stacked. [Means for solving the problem]

[0007] To achieve the above object, the invention of claim 1 provides a gas recovery system that recovers a gas to be recovered from a mixed gas by electrochemical reaction, the system including an electrochemical cell (101) having a working electrode (104) and a counter electrode (106). A plurality of electrochemical cells are stacked, and a gas flow path (102) through which the mixed gas flows is formed between adjacent electrochemical cells. A plate-shaped support member (110) is provided between adjacent electrochemical cells. The support member provides a predetermined gap between adjacent electrochemical cells, and the gap forms the gas flow path. The support member is provided so that its plate surface faces the stacked surface of the electrochemical cells and covers the periphery of the stacked surface of the electrochemical cells. The electrochemical cell has a counter electrode current collector (105) laminated to the counter electrode. When viewed from the stacking direction of the electrochemical cell, the support portion is Other than the counter electrode current collector plate From the area Counter electrode current collector plate overhang Ta department In the stacking direction of the electrochemical cell, the length of the support part is Other than the counter electrode current collector plate It is longer than the other part.

[0008] This allows the support parts to form gaps between adjacent electrochemical cells, thereby maintaining a constant distance between the adjacent electrochemical cells, thereby preventing an increase in pressure loss and variations in the width of the gas flow paths in the electrochemical cells.

[0009] The reference numerals in parentheses for the above components indicate the corresponding relationship with the specific means described in the embodiments to be described later. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a conceptual diagram showing the overall configuration of a carbon dioxide capture system according to a first embodiment. [Figure 2] FIG. 1 is a perspective view of a CO2 capture device. [Figure 3] FIG. 1 is a perspective view showing a state in which a plurality of electrochemical cells are stacked. [Figure 4] FIG. 1 is a perspective view of an electrochemical cell. [Figure 5] FIG. 1 is a perspective view showing an electrochemical cell provided with a support portion according to a first embodiment. [Figure 6] FIG. 2 is a perspective view showing a state in which electrochemical cells provided with a support portion according to the first embodiment are stacked. [Figure 7] FIG. 1 is a side view of an electrochemical cell according to a first embodiment. [Figure 8] FIG. 10 is a partial side view showing a modified example of the inlet side support portion of the first embodiment. [Figure 9] FIG. 10 is a perspective view showing an electrochemical cell provided with a support portion according to a second embodiment. [Figure 10] FIG. 10 is a perspective view showing a state in which electrochemical cells provided with a support portion according to a second embodiment are stacked. [Figure 11] FIG. 10 is a perspective view showing an electrochemical cell provided with a support portion according to a third embodiment. [Figure 12] FIG. 10 is a perspective view showing a support portion of a third embodiment. [Figure 13] FIG. 11 is a perspective view showing a modified example of the support portion of the third embodiment. [Figure 14] FIG. 11 is a perspective view showing a modified example of the support portion of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment will be assigned the same reference numerals, and duplicated explanations may be omitted. In each embodiment, when only a part of the configuration is described, other previously described embodiments may be applied to the other parts of the configuration. In addition to combinations of parts that are specifically specified as being combinable in each embodiment, it is also possible to partially combine embodiments even if not specified, as long as there is no particular problem with the combination. Of the first to third embodiments described below, the first embodiment is an embodiment of the invention set forth in the claims, and the second and third embodiments are forms shown as reference examples.

[0012] (First embodiment) 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 CO2 from a mixed gas. In other words, the gas to be recovered by the gas recovery system is CO2 contained in the mixed gas.

[0013] As shown in Fig. 1, the carbon dioxide capture system 1 of this embodiment is provided with a CO2 capture device 10, a pump 11, a flow path switching valve 12, a CO2 utilization device 13, and a control device 14. In Fig. 1, the mixed gas flows from left to right in the drawing.

[0014] The CO2 capture device 10 is a device that separates and captures CO2 from a mixed gas. The mixed gas is a CO2-containing gas that contains CO2, and can be, for example, the atmosphere or exhaust gas from an internal combustion engine. The mixed gas also contains gases other than CO2. The CO2 capture device 10 is supplied with a mixed gas containing CO2, and discharges the mixed gas after the CO2 has been removed, or CO2 captured from the mixed gas. The configuration of the CO2 capture device 10 will be described in detail later.

[0015] The pump 11 supplies a mixed gas containing CO2 to the CO2 capture device 10 and discharges the mixed gas after the CO2 has been captured from the CO2 capture device 10. In the example shown in Fig. 1, the pump 11 is provided downstream of the CO2 capture device 10 in the gas flow direction, but the pump 11 may also be provided upstream of the CO2 capture device 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 CO2 capture device 10. When the mixed gas after CO2 capture is discharged from the CO2 capture device 10, the flow path switching valve 12 switches the flow path of the exhaust gas to the atmosphere side, and when CO2 is discharged from the CO2 capture device 10, the flow path switching valve 12 switches the flow path of the exhaust gas to the CO2 utilization device 13 side.

[0017] The CO2 utilization device 13 is a device that utilizes CO2. For example, a storage tank that stores CO2 or a conversion device that converts CO2 into fuel can be used as the CO2 utilization device 13. The conversion device can be a device that converts CO2 into a hydrocarbon fuel such as methane. The hydrocarbon fuel may be a gaseous fuel at room temperature and pressure, or a liquid fuel at room 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 processes based on control programs stored in the ROM, and controls the operation of various controlled devices. The control device 14 of this embodiment controls the operation of the CO2 recovery device 10, the operation of the pump 11, and the flow path switching of the flow path switching valve 12, etc.

[0019] Next, the CO2 recovery device 10 will be described with reference to Figures 2 to 6. In Figures 2 to 6, 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 CO2 recovery device 10 is provided with a housing 100. The housing 100 can be made of, for example, a metal material. The housing 100 houses an electrochemical cell 101. The CO2 recovery device 10 adsorbs and desorbs CO2 through an electrochemical reaction in the electrochemical cell 101, and separates and recovers CO2 from the mixed gas.

[0021] The housing 100 has two openings. These two openings are a gas inlet port through which the mixed gas flows into the housing, and a gas outlet port through which the mixed gas and CO2 after CO2 capture flow out of the housing. The gas flow direction is the direction in which the mixed gas flows as it passes through the housing 100, and is the direction from the gas inlet port to the gas outlet port of the housing 100.

[0022] 2, the mixed gas flows from the front side of the drawing to the back side of the drawing. Therefore, the front side of the drawing of the housing 100 is a gas inlet where the mixed gas flows into the interior, and the back side of the drawing is a gas outlet where the mixed gas flows out from the interior. Note that the gas inlet and gas outlet of the housing 100 may be provided with opening and closing members for opening and closing them, respectively.

[0023] As shown in Fig. 2, a plurality of electrochemical cells 101 are stacked and arranged inside a housing 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 is 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 shown spaced apart from one another, but in reality, these components are stacked and arranged so as to be in contact with one another. Furthermore, a support portion 110, which will be described later, is not shown in Figs. 3 and 4.

[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 has 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 electrochemical cell faces the counter electrode current collecting layer 105 of the other electrochemical cell, with a gas flow path 102 sandwiched between them. As shown in FIG. 4, the electrochemical cell 101 has 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, working electrode 104, counter electrode current collecting layer 105, counter electrode 106, and separator 107 are each configured in a plate shape. The electrochemical cell 101 is configured as a laminate in which the working electrode current collecting layer 103, working electrode 104, counter electrode current collecting layer 105, counter electrode 106, and separator 107 are stacked. The direction in which the working electrode current collecting layers 103 and the like of each electrochemical cell 101 are stacked is the same as the cell stacking direction in which 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 CO2 can pass. The working electrode current collecting layer 103 may be made of any material as long as it has gas permeability and conductivity, such as a metal material or a carbonaceous material. In this embodiment, a porous metal body is used as the working electrode current collecting layer 103.

[0029] The working electrode 104 contains a CO2 adsorbent, a conductive material, and a binder. The CO2 adsorbent, the conductive material, and the binder are used in the form of a mixture.

[0030] The CO2 adsorbent absorbs CO2 by receiving electrons and releases the electrons to desorb the absorbed CO2. For example, polyanthraquinone can be used as the CO2 adsorbent.

[0031] The conductive material forms a conductive path to the CO2 adsorbent. Examples of the conductive material include carbon materials such as carbon nanotubes, carbon black, and graphene.

[0032] The binder is provided to hold the CO2 adsorbent and conductive material. Examples of binders that can be used include conductive resins. Examples of conductive resins that can be used include epoxy resins containing Ag or other conductive fillers, and fluororesins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF).

[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 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.

[0035] The electroactive auxiliary material of the counter electrode 106 is an auxiliary electroactive species that exchanges electrons with the CO2 adsorbent of the working electrode 104. For example, a metal complex that can exchange electrons by changing the valence of the metal ion can be used as the electroactive auxiliary material. Examples of such metal complexes include cyclopentadienyl metal complexes such as ferrocene, nickelocene, and cobaltocene, as well as 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 prevent electrical short circuits, and also allows ions to pass through. The separator 107 can be made of 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 nonvolatile at room temperature and normal pressure.

[0038] 4, 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, thereby changing 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] The electrochemical cell 101 can operate in a CO2 capture mode in which CO2 is captured by the working electrode 104, and a CO2 release mode in which CO2 is released from the working electrode 104, by changing the potential difference between the working electrode 104 and the counter electrode 106. The CO2 capture mode is a charge mode in which the electrochemical cell 101 is charged, and the CO2 release mode is a discharge mode in which the electrochemical cell 101 is discharged.

[0040] In the CO2 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 potential of the working electrode is less than the potential of the counter electrode. The first voltage V1 can be set within a range of 0.5 to 2.0 V, for example.

[0041] In the CO2 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 CO2 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] As shown in Fig. 5, an electrochemical cell 101 is provided with an insulating support 110. The support 110 is provided to form a predetermined gap between adjacent electrochemical cells 101. The support 110 is provided for each of the stacked electrochemical cells 101. The support 110 may be made of any material as long as it has insulating properties and a certain degree of rigidity, and for example, a resin material can be used.

[0043] The support member 110 in this embodiment is a plate-like member and is arranged so that its plate surface is parallel to the cell stacking direction. The support member 110 is provided around the electrochemical cell 101. More specifically, the support member 110 is provided in an annular shape so as to cover the stacking surface of the electrochemical cell 101, which is a stack. The stacking surface is the surface of the electrochemical cell 101 viewed from a direction perpendicular to the stacking direction of the components of the electrochemical cell 101, and is the surface on which the components of the electrochemical cell 101 appear to overlap. The support member 110 is provided so that its plate surface faces the stacking surface of the electrochemical cell 101. By covering the stacking surface of the electrochemical cell 101, the support member 110 can function as a dam that prevents the liquid material contained in the electrochemical cell 101 from leaking from the stacking surface.

[0044] 4, the working electrode current collecting layer 103, working electrode 104, counter electrode 106, and separator 107 have the same plate surface size when viewed in the cell stacking direction. In contrast, the counter electrode current collecting layer 105 has a larger plate surface than the working electrode current collecting layer 103, etc. when viewed in the cell stacking direction. Therefore, the counter electrode current collecting layer 105 has a portion that protrudes from the working electrode current collecting layer 103, etc. when viewed in the cell stacking direction.

[0045] 5, the support part 110 is disposed on the plate surface of the counter electrode current collecting layer 105. More specifically, the support part 110 is disposed in a portion of the counter electrode current collecting layer 105 that protrudes from the working electrode current collecting layer 103 and the like when viewed from the cell stacking direction.

[0046] The support portion 110 includes one inlet side support portion 110a, one outlet side support portion 110b, and two side support portions 110c. The inlet side support portion 110a and the outlet side support portion 110b are arranged in parallel with the electrochemical cell 101 interposed therebetween. The two side support portions 110c are arranged in parallel with the electrochemical cell 101 interposed therebetween.

[0047] The inlet side support part 110a is provided on the upstream side of the electrochemical cell 101 in the gas flow direction. The outlet side support part 110b is provided on the downstream side of the electrochemical cell 101 in the gas flow direction. The inlet side support part 110a and the outlet side support part 110b are arranged so that their plate surfaces intersect with the gas flow direction. The side support part 110c is provided so that its plate surface is aligned with the gas flow direction.

[0048] 6, the electrochemical cells 101 are stacked with the supports 110 provided thereon. The side supports 110c provided on the electrochemical cells 101 are in contact with the counter electrode current collecting layers 105 of the adjacent electrochemical cells 101. Therefore, the side supports 110c are sandwiched between the counter electrode current collecting layers 105 of the adjacent electrochemical cells 101. Furthermore, the inlet side supports 110a and the outlet side supports 110b provided on the electrochemical cells 101 are not in contact with the counter electrode current collecting layers 105 of the adjacent electrochemical cells 101.

[0049] As shown in FIG. 7, the height of the side support portions 110c in the cell stacking direction is greater than the height of the electrochemical cells 101 excluding the counter electrode current collecting layers 105. These side support portions 110c form a predetermined gap between adjacent electrochemical cells 101, thereby forming the gas flow path 102. The side support portions 110c keep the gap formed between the working electrode current collecting layer 103 of one electrochemical cell 101 and the counter electrode current collecting layer 105 of the other electrochemical cell 101 constant between the two adjacent electrochemical cells 101. This ensures the flow path width of the gas flow path 102.

[0050] In the cell stacking direction, the height of the side support portion 110c is greater than the height of the inlet-side support portion 110a and the outlet-side support portion 110b. The inlet-side support portion 110a and the outlet-side support portion 110b are not in contact with the counter electrode current collecting layer 105 of the adjacent electrochemical cell 101. Therefore, openings are formed between the inlet-side support portion 110a and the outlet-side support portion 110b and the adjacent electrochemical cell 101. These openings serve as gas flow path inlets 111 through which the mixed gas flows into the gas flow path 102 and gas flow path outlets 112 through which the mixed gas flows out of the gas flow path 102.

[0051] The opening formed between the inlet side support part 110a and the adjacent electrochemical cell 101 is the gas flow path inlet part 111. The opening formed between the outlet side support part 110b and the adjacent electrochemical cell 101 is the gas flow path outlet part 112. The mixed gas that flows into the gas flow path 102 from the gas flow path inlet part 111 flows downstream in the gas flow direction and flows out from the gas flow path outlet part 112.

[0052] Next, the operation of the carbon dioxide capture system 1 of this embodiment will be described.

[0053] As described above, the carbon dioxide capture system 1 operates by alternately switching between a CO2 capture mode and a CO2 release mode. The operation of the carbon dioxide capture system 1 is controlled by the control device 14.

[0054] First, the CO2 capture mode will be described. In the CO2 capture mode, a mixed gas containing CO2 is supplied to the CO2 capture device 10 by operating the pump 11. In the CO2 capture device 10, a voltage applied between the working electrode 104 and the counter electrode 106 of the electrochemical cell 101 is set to a first voltage V1. This allows electron donation from the electroactive auxiliary material of the counter electrode 106 and electron attraction from the CO2 adsorbent material of the working electrode 104 to be achieved simultaneously.

[0055] The CO2 adsorbent of the working electrode 104, which has received electrons from the counter electrode 106, has a higher CO2 binding strength and binds and adsorbs the CO2 contained in the mixed gas. This allows the CO2 recovery device 10 to recover CO2 from the mixed gas.

[0056] After CO2 is captured by the CO2 capture device 10, the mixed gas is discharged from the CO2 capture device 10. The flow path switching valve 12 switches the flow path to the atmosphere side, and the mixed gas discharged from the CO2 capture device 10 is discharged to the atmosphere.

[0057] Next, the CO2 release mode will be described. In the CO2 release mode, the supply of mixed gas to the CO2 capture device 10 is stopped. In the CO2 capture device 10, the voltage applied between the working electrode 104 and the counter electrode 106 of the electrochemical cell 101 is set to a second voltage V2. This allows the CO2 adsorbent material of the working electrode 104 to donate electrons and the electroactive auxiliary material of the counter electrode 106 to attract electrons simultaneously. The CO2 adsorbent material of the working electrode 104 releases electrons and becomes oxidized. The CO2 binding strength of the CO2 adsorbent decreases, causing it to desorb and release CO2.

[0058] The CO2 released from the CO2 adsorbent is discharged from the CO2 recovery device 10. The flow path switching valve 12 switches the flow path to the CO2 utilization device 13 side, and the CO2 discharged from the CO2 recovery device 10 is supplied to the CO2 utilization device 13.

[0059] Note that the interior of the CO2 capture device 10 may be evacuated prior to executing the CO2 release mode. By evacuating the CO2 capture device 10, CO2 can be released in the absence of other gases, and the concentration of the captured CO2 can be increased. To evacuate the CO2 capture device 10, the gas inlet and gas outlet of the housing 100 are closed with an open / close member, and suction is performed using a vacuum pump.

[0060] According to the present embodiment described above, the electrochemical cells 101 are provided with insulating support members 110, and the support members 110 form gaps between adjacent electrochemical cells 101. This makes it possible to maintain a constant distance between adjacent electrochemical cells 101. This makes it possible to prevent an increase in pressure loss and variations in the width of the gas flow path in the electrochemical cells 101.

[0061] Furthermore, the support 110 of this embodiment is provided so as to cover the stacking surface of the electrochemical cell 101. This makes it possible to prevent the liquid substance from leaking from the stacking surface of the electrochemical cell 101 when the electrochemical cell 101 contains a liquid substance.

[0062] In this embodiment, the inlet side support part 110a may have the configuration shown in Fig. 8. Fig. 8 is a side view partially showing the periphery of the gas flow path inlet part 111 in the electrochemical cell 101.

[0063] 8, the surface of inlet side support part 110a facing the upstream side in the gas flow direction forms an inclined surface S that inclines toward the downstream side in the gas flow direction as it approaches gas flow path inlet 111. The mixed gas that flows toward inclined surface S of inlet side support part 110a flows along the surface of inclined surface S and is introduced into gas flow path inlet 111. This makes it possible to reduce pressure loss of the mixed gas near gas flow path inlet 111.

[0064] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to Figures 9 and 10. Only the parts that differ from the first embodiment will be described below.

[0065] As shown in FIGS. 9 and 10, in the electrochemical cell 101 of the second embodiment, the counter electrode current collecting layer 105 has the same plate surface size as the working electrode current collecting layer 103 and the like when viewed in the cell stacking direction.

[0066] 9 and 10, the support portion 113 in the second embodiment is configured as a columnar member. A plurality of support portions 113 are provided. The plurality of support portions 113 have the same length at least in the cell stacking direction.

[0067] The support 113 is disposed between adjacent electrochemical cells 101 and is in contact with each electrochemical cell 101. The support 113 is disposed between two adjacent electrochemical cells 101 so as to be sandwiched between the working electrode current collecting layer 103 of one electrochemical cell 101 and the counter electrode current collecting layer 105 of the other electrochemical cell 101.

[0068] 9 and 10, the support parts 113 are rectangular parallelepipeds, and have a rectangular cross section when viewed from the cell stacking direction. In the example shown in Figures 9 and 10, the support parts 113 are arranged at the four corners and near the center of the plate surface of the electrochemical cell 101, but the number, position, shape, and size of the support parts 113 are not particularly limited.

[0069] According to the second embodiment described above, the columnar support members 113 are provided on the electrochemical cells 101, thereby forming gaps between adjacent electrochemical cells 101. This makes it possible to maintain a constant distance between the adjacent electrochemical cells 101. This makes it possible to suppress an increase in pressure loss and variations in the width of the gas flow path in the electrochemical cells 101.

[0070] (Third embodiment) Next, a third embodiment of the present invention will be described with reference to Figures 11 to 14. Only the parts that differ from the above embodiments will be described below. Although not shown in Figures 12 to 14, counter electrode current collecting layer 105 is in contact with the upper end of support portion 113 in the figures.

[0071] 11, the support part 113 of the third embodiment is configured in a cylindrical shape. The support part 113 is arranged so that the axial direction of the cylinder coincides with the cell stacking direction, and the cross section viewed from the cell stacking direction is circular. In other words, the support part 113 has a curved surface that protrudes toward the upstream side of the gas flow direction at a portion on the upstream side of the gas flow direction.

[0072] 12, the mixed gas flowing toward the support part 113 can flow smoothly downstream in the gas flow direction around the surface of the support part 113. This makes it possible to minimize the pressure loss of the mixed gas caused by providing the support part 113 in the electrochemical cell 101.

[0073] In the third embodiment, the support portion 113 may have the configuration shown in Fig. 13 and Fig. 14. In the examples shown in Fig. 13 and Fig. 14, the cross-sectional shape of the support portion 113 when viewed from the cell stacking direction is circular. In the example shown in Fig. 13, the support portion 113 has a truncated cone shape, and the circular surface with a smaller diameter is in contact with the working electrode current collecting layer 103. In the example shown in Fig. 14, the support portion 113 has a shape formed by combining two cylinders with different diameters, and the cylindrical portion with the smaller diameter is in contact with the working electrode current collecting layer 103.

[0074] 13 and 14, the cross-sectional area of ​​support portion 113 as viewed in the cell stacking direction is smaller in a portion closer to working electrode 104 than in a portion farther from working electrode 104. In the example shown in Fig. 13, the cross-sectional area of ​​support portion 113 as viewed in the cell stacking direction continuously decreases from a portion farther from working electrode 104 to a portion closer to working electrode 104. In the example shown in Fig. 14, the cross-sectional area of ​​support portion 113 as viewed in the cell stacking direction decreases stepwise from a portion farther from working electrode 104 to a portion closer to working electrode 104.

[0075] 13 and 14 , the mixed gas flowing toward the support portion 113 flows around the surface of the support portion 113 downstream in the gas flow direction, and simultaneously flows downward in the figure along the surface of the support portion 113. In other words, part of the mixed gas flowing toward the support portion 113 flows toward the working electrode current collecting layer 103. This can promote the uptake of the mixed gas into the working electrode 104.

[0076] (Other embodiments) The present invention is not limited to the above-described embodiments, and various modifications can be made as follows without departing from the spirit of the present invention. Furthermore, the means disclosed in each of the above-described embodiments may be combined as appropriate within the scope of feasibility.

[0077] For example, in each of the above embodiments, an example has been described in which the gas recovery system of the present invention is applied to a carbon dioxide recovery system 1 that recovers CO2 from a mixed gas, but this is not limited to this, and the gas recovery system of the present invention can be applied to a configuration in which a specific type of gas other than CO2 is recovered from a mixed gas. [Explanation of symbols]

[0078] 101 Electrochemical Cell 104 Working electrode 106 Opposite 110 Support part (plate-shaped member) 110a Inlet side support part 110c Lateral support 111 Gas flow path inlet 112 Gas flow path outlet 113 Support part (columnar member)

Claims

1. A gas recovery system that recovers a gas to be recovered from a mixed gas by an electrochemical reaction, A plurality of electrochemical cells (101) each having a working electrode (104) and a counter electrode (106), By applying a voltage between the working electrode and the counter electrode, the working electrode can adsorb the gas to be recovered contained in the mixed gas, the plurality of electrochemical cells are stacked; A gas flow path (102) through which the mixed gas flows is formed between adjacent electrochemical cells, The electrochemical cells have plate-like support portions (110) that form a predetermined gap between adjacent electrochemical cells, The gap forms a gas flow path (102) through which the mixed gas flows, the support portion has a plate surface facing the stacking surface of the electrochemical cell and is provided to cover the periphery of the stacking surface of the electrochemical cell, The electrochemical cell has a counter electrode current collector (105) laminated on the counter electrode, When viewed from a stacking direction of the electrochemical cell, the support portion is disposed at a portion of the electrochemical cell where the counter electrode current collector plate protrudes from a portion other than the counter electrode current collector plate, A gas recovery system, wherein the length of the support portion in the stacking direction of the electrochemical cells is longer than a portion of the electrochemical cells other than the counter electrode current collector plate.

2. When the direction connecting the gas flow path inlet (111) through which the mixed gas flows into the gas flow path and the gas flow path outlet (112) through which the mixed gas flows from the gas flow path is defined as the gas flow direction, the support portion includes an inlet side support portion (110a) and an outlet side support portion (110b) that are arranged so that their plate surfaces intersect with the gas flow direction, and a side support portion (110c) that has a plate surface provided along the gas flow direction, the inlet side support portion and the outlet side support portion have lengths in a stacking direction of the electrochemical cells that are shorter than the lengths of the side support portions, 2. The gas recovery system according to claim 1, wherein the gas flow path inlet portion is formed between the inlet side support portion and the adjacent electrochemical cell, and the gas flow path outlet portion is formed between the outlet side support portion and the adjacent electrochemical cell.

3. A gas recovery system as described in Claim 2, wherein the inlet side support portion has an inclined surface (S) whose surface facing upstream in the gas flow direction slopes toward the downstream side of the gas flow as it approaches the gas flow path inlet portion.

4. The gas to be recovered is CO ２ 4. The gas recovery system according to claim 1, wherein:

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