Carbon dioxide conversion apparatus and operation method thereof

Abstract

To improve the utilization efficiency of carbon dioxide.SOLUTION: A carbon dioxide conversion apparatus comprises an electrolytic unit and a collection unit. The collection unit comprises: a first air bubble disperser for generating a third fluid including a first air bubble dispersion liquid obtained by dispersing a first fluid discharged from the electrolytic unit including carbon dioxide and oxygen into a second fluid including an absorbent together with air bubbles; a first separation unit for generating a fourth fluid including the absorbent containing the carbon dioxide by cooling the third fluid and separating the oxygen from the cooled third fluid; a second separation unit for separating a sixth fluid containing a gas from the fifth fluid after generating a fifth fluid including a gas with the carbon dioxide and water vapor and a liquid with the absorbent by heating the fourth fluid from the first separation unit and evaporating the absorbent; and a third separation unit for separating a seventh fluid containing the carbon dioxide from the cooled sixth fluid obtained by cooling the sixth fluid.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the present invention relate to carbon dioxide conversion apparatus and methods of operating a carbon dioxide conversion apparatus. [Background technology]

[0002] As global warming progresses, there is a demand to reduce the use of natural gas, coal, and oil, which generate carbon dioxide (CO2). In addition, development is underway on chemical synthesis using carbon dioxide as a raw material. As part of this, there are carbon dioxide conversion devices that electrolyze carbon dioxide to generate carbon monoxide (CO)-containing gas. In carbon dioxide conversion devices, an amount of carbon dioxide equal to the amount of carbon compounds such as carbon monoxide generated moves to the anode side and is released together with oxygen. As a result, the effective utilization rate of carbon dioxide supplied to the carbon dioxide conversion device is low, at 50% or less. For this reason, there is a demand for a carbon dioxide conversion device and a carbon dioxide conversion method that have a high utilization rate of carbon dioxide.

[0003] However, in the carbon dioxide conversion apparatuses that have been considered so far, the same amount of carbon dioxide as the amount of carbon monoxide generated is released together with oxygen from the supplied carbon dioxide, resulting in a low conversion rate of the supplied carbon dioxide to carbon monoxide and a low utilization rate of carbon dioxide. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] JA Rabinowiz, MW Kanan, The future of low-temperature carbon dioxide electrolysis depends on solving one basic problem, Nature Communications, 11, Article number:5231(2020)<https: / / doi.org / 10.1038 / s41467-020-19135-8> Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to improve the efficiency of carbon dioxide utilization. [Means for solving the problem]

[0006] The carbon dioxide conversion device of the embodiment includes an electrolysis unit that electrolyzes carbon dioxide to generate carbon monoxide, and a recovery unit that recovers carbon dioxide discharged from the electrolysis unit. The recovery unit includes a first bubble disperser that generates a third fluid containing a first bubble dispersion by dispersing a first fluid discharged from the electrolysis unit and containing carbon dioxide and oxygen into a second fluid containing an absorbing liquid, a first separation unit that cools the third fluid and separates oxygen from the cooled third fluid to generate a fourth fluid containing an absorbing liquid containing carbon dioxide, a second separation unit that heats the fourth fluid from the first separation unit to evaporate the absorbing liquid to generate a fifth fluid containing a gas containing carbon dioxide and water vapor and a liquid containing the absorbing liquid, and separates a sixth fluid containing the gas from the fifth fluid, and a third separation unit that cools the sixth fluid and separates a seventh fluid containing carbon dioxide from the cooled sixth fluid. [Brief description of the drawings]

[0007] [Figure 1] 1 is a block diagram showing a configuration example of a carbon dioxide conversion apparatus according to an embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a configuration example of an electrolysis unit 10. [Diagram 3] FIG. 2 is a schematic cross-sectional view showing a structural example of an electrolysis cell stack 101. [Figure 4] 2 is a schematic diagram showing a configuration example of a recovery section 20. FIG. [Diagram 5] FIG. 2 is a schematic cross-sectional view showing a structural example of a vortex turbo mixer. [Figure 6] 13 is a schematic diagram showing another configuration example of the recovery section 20. FIG. [Figure 7]13 is a schematic diagram showing another configuration example of the recovery section 20. FIG. [Figure 8] 13 is a schematic diagram showing another configuration example of the recovery section 20. FIG. [Figure 9] 13 is a schematic diagram showing another configuration example of the recovery section 20. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the carbon dioxide conversion device of the embodiment will be described with reference to the drawings. In each embodiment shown below, the substantially same components are given the same reference numerals, and the description thereof may be partially omitted. The drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each part, etc. may differ from the actual ones.

[0009] In this specification, "connect" includes not only direct connection but also indirect connection unless otherwise specified. Furthermore, in this specification, "connect" includes not only physical connection but also electrical connection unless otherwise specified.

[0010] An example of the configuration of a carbon dioxide conversion apparatus according to an embodiment will be described below. Fig. 1 is a block diagram showing an example of the configuration of a carbon dioxide conversion apparatus according to an embodiment. Fig. 1 shows a carbon dioxide conversion apparatus 1.

[0011] The carbon dioxide conversion device 1 includes an electrolysis unit 10 and a recovery unit 20. The electrolysis unit 10 can perform an electrolytic reaction, for example, electrolyze carbon dioxide to generate carbon compounds such as carbon monoxide. The recovery unit 20 can recover, for example, carbon dioxide discharged from the electrolysis unit 10. The carbon dioxide discharged from the electrolysis unit 10 is, for example, unreacted carbon dioxide that has not been used in the electrolytic reaction in the electrolysis unit 10.

[0012] 2 is a schematic diagram showing a configuration example of the electrolysis unit 10. The electrolysis unit 10 includes, for example, an electrolysis cell stack 101, a gas-liquid separator S1, a cooler C1, a gas-liquid separator S2, a cooler C2, a storage tank (tank) 102, a pump 103, a cooler C3, a gas-liquid separator S3, a valve 104, a flow path P1, a flow path P2, a flow path P3, a flow path P4, a flow path P5, a flow path P6, a flow path P7, a flow path P8, a flow path P9, a flow path P10, a flow path P11, a flow path P12, and a flow path P13.

[0013] The electrolysis cell stack 101 can perform, for example, an electrolysis reaction. FIG. 3 is a cross-sectional schematic diagram showing a structural example of the electrolysis cell stack 101. The electrolysis cell stack 101 shown in FIG. 3 has an anode 111, a cathode 112, a diaphragm 113, and a flow path plate 114. The anode 111, the cathode 112, and the diaphragm 113 are stacked, for example, in the Z-axis direction to form a carbon dioxide electrolysis cell 110. FIG. 3 shows an X-axis, a Y-axis, and a Z-axis. The X-axis, the Y-axis, and the Z-axis perpendicularly intersect with each other. The Z-axis is along the thickness direction of the carbon dioxide electrolysis cell 110. FIG. 3 shows a part of an XZ cross section including the X-axis and the Z-axis. FIG. 3 shows a plurality of cathodes 112, a plurality of anodes 111, a plurality of diaphragms 113, and a plurality of flow path plates 114.

[0014] Examples of the electrolysis cell stack 101 include a carbon dioxide electrolysis cell stack. The electrolysis cell stack 101 has, for example, a plurality of carbon dioxide electrolysis cells 110. The plurality of carbon dioxide electrolysis cells 110 are stacked with a flow path plate 114 sandwiched therebetween. The plurality of carbon dioxide electrolysis cells 110 may be disposed, for example, between a plurality of supports (not shown). The number of stacked carbon dioxide electrolysis cells 110 is not particularly limited, but is, for example, eight or more. The electrolysis unit 10 may have a plurality of electrolysis cell stacks 101.

[0015] The anode 111 is connected to a power source, for example, via an anode current collector provided at the end of the electrolysis cell stack 101. The anode 111 can, for example, oxidize carbonate ions and bicarbonate ions generated at the cathode to generate oxygen gas and carbon dioxide. In addition, the anode 111 may also carry out electrolytic reactions other than the above reactions. These reactions include, for example, reactions represented by the following formulas (1), (2), and (3). CO3 2- +H2O → CO2+2OH - (1) HCO3 - → CO2+OH - (2) 2OH - → H2O+0.5O2+2e - (3)

[0016] The anode 111 has, for example, a catalyst that promotes an electrolytic reaction. The catalyst is supported on the surface of a conductive substrate such as a metal. The catalyst may form a catalyst layer provided on the surface of the conductive substrate.

[0017] The cathode 112 is connected to a power source, for example, via a cathode current collector provided at the end of the electrolysis cell stack 101. The cathode 112 can, for example, reduce carbon dioxide to produce carbon compounds such as carbon monoxide. In addition, the cathode 112 may carry out electrolytic reactions other than the above reactions. These reactions include, for example, reactions represented by the following formulas (4), (5), (6), and (7). CO2+H2O+2e - → CO+2OH - (4) 2H2O+2e - → H2+2OH - (5) CO2+2OH - → CO3 2- +H2O···(6) CO2+OH - → HCO3 - (7)

[0018] The cathode 112 has, for example, a catalyst that promotes an electrolytic reaction. The catalyst is supported on the surface of a conductive substrate such as a metal. The catalyst may form a catalyst layer provided on the surface of the conductive substrate.

[0019] The diaphragm 113 is disposed, for example, between the anode 111 and the cathode 112. The diaphragm 113 may be provided in contact with each of the anode 111 and the cathode 112. The diaphragm 113 is configured to, for example, absorb hydrogen ions (H + ), hydroxide ion (OH - ), carbonate ion (CO3 2- ), hydrogen carbonate ion (HCO3 - The diaphragm 113 includes, for example, at least one of an ion exchange membrane or a porous membrane.

[0020] The flow path plate 114 is provided to separate the two carbon dioxide electrolysis cells 110. The flow path plate 114 can, for example, isolate the atmospheres of the adjacent carbon dioxide electrolysis cells 110. The flow path plate 114 can be formed using, for example, a conductive material such as a metal, a carbon material, or a conductive ceramic.

[0021] The flow channel plate 114 has a flow channel 114a and a flow channel 114b. The shapes of the flow channels 114a and 114b are not limited to the shapes shown in Fig. 3. The shapes of the flow channels 114a and 114b may be serpentine or rectangular on the surfaces of the flow channel plate 114 facing the anode 111 and the cathode 112, respectively.

[0022] The flow path 114a is provided on the surface of the flow path plate 114 on the anode 111 side, and faces the anode 111. The flow path 114a can pass, for example, a fluid including a supply liquid and an oxidation product such as water, oxygen gas, or carbon dioxide gas. The flow path 114a can form, for example, an anode chamber. The flow path 114a has, for example, an inlet connected to the flow path P1 and an outlet connected to the flow path P3.

[0023] The flow path 114b is provided on the surface of the flow path plate 114 on the cathode 112 side (opposite to the flow path 114a) and faces the cathode 112. The flow path 114b can pass, for example, a supply gas or a fluid containing a reduction product such as a carbon compound. The flow path 114b can form, for example, a cathode chamber. The flow path 114b has, for example, an inlet connected to the flow path P2 and an outlet connected to the flow path P4.

[0024] The supply liquid includes, for example, an electrolyte. An example of the electrolyte is a solution using water (H2O), for example, an aqueous solution containing any electrolyte. An example of the aqueous solution containing an electrolyte is a solution containing phosphate ions (PO4 2- ), borate ion (BO3 3- ), sodium ion (Na + ), potassium ion (K + ), calcium ion (Ca 2+ ), lithium ion (Li + ), Cesium ion (Cs + ), magnesium ion (Mg 2+ ), chloride ion (Cl - ), hydrogen carbonate ion (HCO3 - ), carbonate ion (CO3 2- ), hydroxide ion (OH - Examples of the electrolyte include aqueous solutions containing potassium hydroxide (KOH), potassium bicarbonate (KHCO3), potassium carbonate (K2CO3), and the like.

[0025] The flow path P1 can be connected to an inlet of the flow path 114a. The flow path P1 can be connected to an anode supply fluid supply source. The anode supply fluid supply source can supply, for example, an anode supply fluid AF. The anode supply fluid AF can include, for example, a liquid such as a supply liquid.

[0026] The flow path P2 can be, for example, through which the cathode supply fluid CF supplied to the flow path 114b flows. The flow path P2 is connected to an inlet of the flow path 114b. The cathode supply fluid CF contains gaseous carbon dioxide. The flow path P2 may be connected to a cathode supply fluid supply source such as a carbon dioxide supply source. The carbon dioxide supply source can supply, for example, a fluid containing gaseous carbon dioxide. The carbon dioxide supply source can separate and recover carbon dioxide gas from an exhaust gas (CO2-containing gas) containing carbon dioxide gas discharged from facilities such as a thermal power plant, a waste incineration plant, and a steelworks, and supply the separated supply gas containing carbon dioxide gas to the electrolysis cell stack 101. The carbon dioxide supply source may be, for example, a chemical absorption method using a chemical absorption liquid such as an amine aqueous solution, a physical absorption method using a physical absorption liquid such as methanol or a polyethylene glycol solution, a solid absorption method using a solid absorbent such as an amine compound, a membrane separation method using a carbon dioxide separation membrane, a physical absorption method using an inorganic material such as zeolite as an adsorbent, a pressure swing adsorption (PSA) method, a thermal swing adsorption (TSA) method, or the like. For example, a chemical absorption method and device using an amine aqueous solution may supply exhaust gas to an absorption tower in which the amine aqueous solution flows down, and the amine aqueous solution that has absorbed carbon dioxide may be heated in a regeneration tower to recover carbon dioxide released from the amine aqueous solution. The carbon dioxide supply source may be any of various methods and devices capable of recovering carbon dioxide from exhaust gas (CO2-containing gas). The carbon dioxide conversion device may have a humidifier that humidifies carbon dioxide gas from the carbon dioxide supply source, and the gas humidified by the humidifier may be supplied to the electrolysis cell stack 101 as the cathode supply fluid CF.

[0027] The flow path P3 allows the anode exhaust fluid AF1 discharged from the flow path 114a to flow. The anode exhaust fluid AF1 contains, for example, a gas such as oxygen or carbon dioxide, and a liquid such as a feed liquid, and forms a gas-liquid two-phase flow. The flow path P3 is connected to the outlet of the flow path 114a. The flow path P3 functions, for example, as an anode exhaust flow path.

[0028] The flow path P4 allows the cathode exhaust fluid CF1 discharged from the flow path 114b to flow. The flow path P4 is connected to the outlet of the flow path 114b. The flow path P4 has a function as, for example, a cathode exhaust flow path.

[0029] The gas-liquid separator S1 separates, for example, the anode exhaust fluid AF1 discharged from the flow path 114a into an anode exhaust fluid AF2 and an anode exhaust fluid AF3. The anode exhaust fluid AF2 includes a gas containing oxygen and carbon dioxide. The anode exhaust fluid AF3 includes a liquid containing a supply liquid. The gas-liquid separator S1 is connected, for example, to the flow path P3.

[0030] The cooler C1 can, for example, cool the anode exhaust fluid AF2 from the gas-liquid separator S1. The cooled anode exhaust fluid AF2 contains, for example, a gas containing oxygen and carbon dioxide, and a liquid such as a feed liquid. The cooler C1 is connected to the gas-liquid separator S1 via a flow path P5. The flow path P5 allows the anode exhaust fluid AF2 to flow. The flow path P5 functions, for example, as an anode exhaust flow path.

[0031] The gas-liquid separator S2, for example, processes the anode discharge fluid AF2 cooled by the cooler C1 to separate the anode discharge fluid AF2 into an anode discharge fluid AF4 and an anode discharge fluid AF5. The anode discharge fluid AF4 is formed by removing liquid such as a feed liquid from the anode discharge fluid AF2, and contains gas such as oxygen and carbon dioxide. The gas-liquid separator S2 is connected to the cooler C1 via a flow path P6 and is provided at the rear of the cooler C1. The cooled anode discharge fluid AF2 can flow through the flow path P6. The flow path P6 has a function as, for example, an anode discharge flow path. The anode discharge fluid AF5 contains liquid such as a feed liquid removed from the anode discharge fluid AF2. The anode discharge fluid AF5 is supplied to the storage tank 102 via a flow path P7. The flow path P7 allows the anode discharge fluid AF5 to flow through. The flow path P7 connects the gas-liquid separator S2 and the storage tank 102. The flow path P7 has a function as, for example, an anode discharge flow path.

[0032] The cooler C1 and the gas-liquid separator S2 form a separation section that cools the anode discharge fluid AF2 from the gas-liquid separator S1 and processes the anode discharge fluid AF2 to separate an anode discharge fluid AF4 containing oxygen and carbon dioxide from the anode discharge fluid AF2.

[0033] The cooler C2 can cool, for example, the anode discharge fluid AF3. The cooler C2 is connected, for example, to a flow path P8 and is provided at a rear stage of the gas-liquid separator S1. The flow path P8 is connected to the gas-liquid separator S1. The flow path P8 can allow the anode discharge fluid AF3 to flow. The flow path P3 has a function as, for example, an anode discharge flow path. The cooled anode discharge fluid AF3 includes a liquid such as a supply liquid. The cooled anode discharge fluid AF3 is supplied to the storage tank 102 via the flow path P9. The flow path P9 connects the cooler C2 and the storage tank 102. The flow path P9 can allow the cooled anode discharge fluid AF3 to flow.

[0034] The storage tank 102 contains a liquid such as a supply liquid. The contained liquid includes an anode exhaust fluid AF3, an anode exhaust fluid AF5, and a cathode exhaust fluid CF3. The contained liquid is supplied to the flow path P1 as an anode supply fluid AF, for example, by using a pump 103 connected via a flow path P10. The flow path P10 connects the storage tank 102 and the pump 103. The flow path P10 functions as an anode circulation flow path. The pump 103 is connected to the flow path P1.

[0035] The cooler C3 can cool, for example, the cathode exhaust fluid CF1 discharged from the flow path 114b. The cooled cathode exhaust fluid CF1 contains carbon monoxide, carbon dioxide, and a liquid containing water and an electrolyte. The cooler C3 is connected to, for example, a flow path P4 connected to the outlet of the flow path 114b.

[0036] The gas-liquid separator S3 separates the cooled cathode discharge fluid CF1 into a cathode discharge fluid CF2 and a cathode discharge fluid CF3. The cathode discharge fluid CF2 contains gases such as carbon monoxide and carbon dioxide. The cathode discharge fluid CF3 contains liquids such as water and an electrolyte. The gas-liquid separator S3 is connected to a flow path P11 connected to the cooler C3. The flow path P11 allows the cooled cathode discharge fluid CF1 to flow. The flow path P11 connects the cooler C3 and the gas-liquid separator S3. The flow path P11 has a function as, for example, a cathode discharge flow path.

[0037] The cooler C3 and the gas-liquid separator S3 cool the cathode discharge fluid CF1 discharged from the flow path 114b, and form a separation section that processes the cooled cathode discharge fluid CF1 to separate the cathode discharge fluid CF3 from the cathode discharge fluid CF1.

[0038] An example of the valve 104 is a pressure reducing valve. The valve 104 is connected to, for example, a flow path P12 connected to the gas-liquid separator S3. The flow path P12 allows the cathode discharge fluid CF3 to flow. The flow path P12 connects the gas-liquid separator S3 and the valve 104. The flow path P12 has a function as, for example, a cathode circulation flow path. The valve 104 is connected to, for example, a flow path P13 connected to the storage tank 102. The flow path P13 allows the cathode discharge fluid CF3 to flow. The flow path P13 connects the valve 104 and the storage tank 102. The flow path P13 has a function as, for example, a cathode circulation flow path. The valve 104 can suppress the backflow of the cathode discharge fluid CF3 from the storage tank 102 to the gas-liquid separator S3. The cathode discharge fluid CF3 is supplied to the storage tank 102 via the flow path P13. The liquid contained in the reservoir 102 comprises the cathode exhaust fluid CF3.

[0039] Each of the flow paths P1, P2, P3, P4, P5, P6, P7, P8, P9, P10, P11, P12, and P13 can be formed using, for example, piping.

[0040] 4 is a schematic diagram showing a configuration example of the recovery section 20. The recovery section 20 includes, for example, a vortex turbo mixer TM1, a cooler C4, a gas-liquid separator S4, a vortex turbo mixer TM2, a cooler C5, a gas-liquid separator S5, a heat exchanger TE, an evaporator EP, a gas-liquid separator S6, a cooler C6, a gas-liquid separator S7, a condenser CD, a vortex turbo mixer TM3, a cooler C7, a gas-liquid separator S8, a flow path P14, a flow path P15, a flow path P16, a flow path P17, a flow path P18, a flow path P19, a flow path P20, a flow path P21, a flow path P22, a flow path P23, a flow path P24, a flow path P25, a flow path P26, a flow path P27, a flow path P28, a flow path P29, and a flow path P30. Each of the flow paths P14, P15, P16, P17, P18, P19, P20, P21, P22, P23, P24, P25, P26, P27, P28, P29, and P30 can be formed using, for example, piping.

[0041] The vortex turbo mixer TM1 generates a recovered fluid RF1 containing a bubble dispersion by dispersing the anode discharge fluid AF4 discharged from the electrolysis unit 10 into an absorbing fluid. The vortex turbo mixer TM1 is connected to the gas-liquid separator S2 shown in Fig. 2 via a flow path such as a pipe. An example of the vortex turbo mixer TM1 is the vortex turbo mixer KTM manufactured by Nikuni Co., Ltd.

[0042] The cooler C4 can cool, for example, the recovery fluid RF1 from the vortex turbo mixer TM1. The cooler C4 is connected to the vortex turbo mixer TM1 via a flow path P14 connected to the outlet of the vortex turbo mixer TM1. The flow path P14 can be a flow path through which the recovery fluid RF1 can flow. The flow path P14 has a function as a recovery flow path.

[0043] The gas-liquid separator S4 can generate a recovery fluid RF2 by, for example, processing the recovery fluid RF1 cooled by the cooler C4 and separating a fluid containing a non-condensable / non-absorbed gas WG1 from the recovery fluid RF1. The non-condensable / non-absorbed gas WG1 contains, for example, oxygen. The gas-liquid separator S4 is connected to the cooler C4 via, for example, a flow path P15 and is provided at the rear of the cooler C4. The flow path P15 can allow, for example, the cooled recovery fluid RF1 to flow. The flow path P15 functions as a recovery flow path.

[0044] The cooler C4 and the gas-liquid separator S4 cool the recovered fluid RF1 from the vortex turbo mixer TM1 and form a separation section that processes the cooled recovered fluid RF1 to separate a fluid containing non-condensable / non-absorbed gas WG1 from the recovered fluid RF1.

[0045] The vortex turbo mixer TM2 generates a recovery fluid RF3 containing a bubble dispersion by dispersing the supply fluid SF supplied from a carbon dioxide supply source into the recovery fluid RF2 from the gas-liquid separator S4. The supply fluid SF contains, for example, carbon dioxide and a gas other than carbon dioxide. The inlet of the vortex turbo mixer TM2 is connected to, for example, a carbon dioxide supply source. The inlet of the vortex turbo mixer TM2 is connected to the gas-liquid separator S4 via, for example, a flow path P16, and is provided at the rear of the gas-liquid separator S4. The flow path P16 allows, for example, the recovery fluid RF2 to flow. The flow path P16 functions as a recovery flow path. An example of the vortex turbo mixer TM2 includes a vortex turbo mixer KTM manufactured by Nikuni Co., Ltd.

[0046] The cooler C5 can cool, for example, the recovery fluid RF3 from the vortex turbo mixer TM2. The cooler C5 is connected, for example, to a flow path P17 connected to the outlet of the vortex turbo mixer TM2, and is provided at the rear of the vortex turbo mixer TM2. The flow path P17 can be a passage through which the recovery fluid RF3 flows. The flow path P17 functions as a recovery flow path.

[0047] The gas-liquid separator S5, for example, processes the recovery fluid RF3 cooled by the cooler C5, and separates a fluid containing the non-condensed / non-absorbed gas WG2 from the recovery fluid RF3, thereby generating a recovery fluid RF4 containing an absorbing liquid containing carbon dioxide. The non-condensed / non-absorbed gas WG2 contains, for example, oxygen and hydrogen. The gas-liquid separator S5 is connected to the cooler C5 via, for example, a flow path P18, and is provided at the rear of the cooler C5. The flow path P18 can be used to allow the cooled recovery fluid RF3 to flow. The flow path P18 has a function as a recovery flow path. The recovery fluid RF4 is supplied to the heat exchanger TE via a flow path P19. The flow path P19 can be used to allow the recovery fluid RF4 to flow. The flow path P19 has a function as a recovery flow path.

[0048] The cooler C5 and the gas-liquid separator S5 cool the recovered fluid RF3 from the vortex turbo mixer TM2 and form a separation section that processes the cooled recovered fluid RF3 to separate a fluid containing non-condensable / non-absorbed gas WG2 from the recovered fluid RF3.

[0049] The evaporator EP heats the recovery fluid RF4 supplied from the gas-liquid separator S5 via the heat exchanger TE to evaporate the liquid in the recovery fluid RF4, thereby generating a recovery fluid RF5 containing carbon dioxide gas, water vapor, and an absorbing liquid. The evaporator EP is connected to the heat exchanger TE via, for example, a flow path P20. The flow path P20 allows, for example, the heat-exchanged recovery fluid RF4 to flow. The flow path P20 functions as a recovery flow path.

[0050] The gas-liquid separator S6 can process the recovery fluid RF5 supplied from the evaporator EP via a flow path P21, for example, and separate it into a recovery fluid RF6 and a recovery fluid RF7. The recovery fluid RF6 contains carbon dioxide gas and water vapor. The recovery fluid RF7 contains a liquid such as an absorption liquid. The gas-liquid separator S6 is connected to the evaporator EP via the flow path P21 and is provided at the rear of the evaporator EP. The flow path P21 can be used to allow the recovery fluid RF5 to flow, for example. The flow path P21 functions as a recovery flow path.

[0051] The heat exchanger TE exchanges heat between the recovery fluid RF4 from the flow path P19 and the recovery fluid RF7 from the flow path P22. Due to the heat exchange, the temperature of the recovery fluid RF4 from the flow path P19 increases, and the temperature of the recovery fluid RF7 from the flow path P22 increases. The heat-exchanged recovery fluid RF4 is supplied to the evaporator EP via the flow path P20. The heat exchanger TE is connected to the flow paths P19, P20, and P22. The heat exchanger TE may connect the flow paths P19 and P20, and connect the flow paths P22 and P26, and exchange heat between these connection points.

[0052] The cooler C6 can cool, for example, the recovery fluid RF6 supplied from the gas-liquid separator S6 via a flow path P23. The cooler C6 is connected to, for example, the flow path P23 connected to the gas-liquid separator S6, and is provided at the rear of the gas-liquid separator S6. The flow path P23 can be used by, for example, the recovery fluid RF6 to flow. The flow path P23 functions as a recovery flow path.

[0053] The gas-liquid separator S7 can, for example, process the recovery fluid RF6 cooled by the cooler C6 to separate the recovery fluid RF6 into recovery fluid RF8 and recovery fluid RF9. The recovery fluid RF8 contains a liquid such as an absorption liquid. The recovery fluid RF9 contains a gas such as carbon dioxide. The gas-liquid separator S7 is, for example, connected to the cooler C6 via a flow path P24 and is provided at the rear of the cooler C6. The flow path P24 can, for example, allow the cooled recovery fluid RF6 to flow. The flow path P24 functions as a recovery flow path.

[0054] The cooler C6 and the gas-liquid separator S7 cool the recovery fluid RF6 supplied from the gas-liquid separator S6 via the flow path P23, and form a separation section that processes the cooled recovery fluid RF6 to separate the recovery fluid RF9 from the recovery fluid RF6.

[0055] The condenser CD can condense the recovery fluid RF8 supplied from the gas-liquid separator S7 via the flow path P25 and the recovery fluid RF7 supplied from the heat exchanger via the flow path P26 to generate a recovery fluid RF10 containing an absorbing liquid. The condenser CD is connected to the gas-liquid separator S7 via the flow path P25, for example, and is provided at the rear of the gas-liquid separator S7. The flow path P25 can be used to allow the recovery fluid RF7 and the recovery fluid RF8 to flow, for example. The flow path P25 functions as a recovery flow path. The condenser CD is connected to the heat exchanger TE via the flow path P26, for example. The flow path P26 can be used to allow the heat-exchanged recovery fluid RF7 to flow, for example. The flow path P26 functions as a recovery flow path.

[0056] The vortex turbo mixer TM3 can generate a recovered fluid RF11 by dispersing the cathode discharge fluid CF2 supplied from the electrolysis unit 10 into a recovered fluid RF10 supplied from the condenser CD through a flow path P27. The inlet of the vortex turbo mixer TM3 is connected to the condenser CD through the flow path P27, for example. The inlet of the vortex turbo mixer TM3 is connected to the gas-liquid separator S2 shown in FIG. 2 through a flow path such as a pipe. The flow path P27 can be used to allow the recovered fluid RF10 to flow, for example. The flow path P27 functions as a recovery flow path. Examples of the vortex turbo mixer TM3 include the vortex turbo mixer KTM manufactured by Nikuni Co., Ltd.

[0057] The cooler C7 can cool, for example, the recovery fluid RF11 supplied from the vortex turbo mixer TM3 through a flow path P28. The cooler C7 is connected to, for example, the flow path P28 connected to the outlet of the vortex turbo mixer TM3. The flow path P28 can be used by, for example, the recovery fluid RF11 to flow through. The flow path P28 functions as a recovery flow path.

[0058] The gas-liquid separator S8 can generate a recovery fluid RF12 containing an absorbing liquid containing carbon dioxide by, for example, processing the recovery fluid RF11 cooled by the cooler C7 and separating a fluid containing a non-condensed / non-absorbed gas WG3 from the recovery fluid RF11. The non-condensed / non-absorbed gas WG3 contains, for example, oxygen and hydrogen. The gas-liquid separator S8 is connected to the cooler C7 via, for example, a flow path P29 and is provided at the rear of the cooler C7. The flow path P29 can be used to allow, for example, the cooled recovery fluid RF11 to flow. The flow path P29 functions as a recovery flow path.

[0059] The cooler C7 and the gas-liquid separator S8 form a separation section that cools the recovery fluid RF11 supplied from the vortex turbo mixer TM3 via flow path P28, processes the cooled recovery fluid RF11, and separates a fluid containing non-condensable / non-absorbed gas WG3 from the recovery fluid RF11.

[0060] The recovered fluid RF12 from the gas-liquid separator S8 is supplied to the vortex turbo mixer TM1 as an absorption fluid via a flow path P30. The flow path P30 allows, for example, the recovered fluid RF12 to flow. The flow path P30 functions as a recovery flow path.

[0061] Here, a structural example of a vortex turbo mixer applicable to the vortex turbo mixers TM1, TM2, and TM3 will be further described. Fig. 5 is a cross-sectional schematic diagram showing a structural example of a vortex turbo mixer. Fig. 5 shows the vortex turbo mixer TM.

[0062] The vortex turbo mixer TM is one of the mixing devices (air bubble dispersers) and includes a processing chamber 211, a rotor 212, a valve V1, a valve V2, and a valve V3. The vortex turbo mixer TM may be connected to a power source and may operate in response to power supplied from the power source. In the embodiment, the vortex turbo mixer TM is exemplified as an air bubble disperser, but the air bubble disperser is not limited to the vortex turbo mixer TM as long as it can disperse air bubbles from a fluid containing gas into a fluid containing liquid. As other air bubble dispersers, for example, an ejector, a mixer, an aeration device, an aeration device, a gas-liquid cocurrent packed bubble column which is a gas-liquid contact column packed with a packing material, or two or more of these air bubble dispersers may be used in combination.

[0063] The processing chamber 211 is a space for dispersing a fluid A containing a liquid and a fluid B containing a gas into bubbles. The fluid A contains an absorbing liquid capable of dissolving carbon dioxide. The fluid B contains carbon dioxide gas. Examples of the absorbing liquid include an absorbing liquid containing an amine. The absorbing liquid containing an amine easily dissolves carbon dioxide and does not easily dissolve other gases such as oxygen and hydrogen. The processing chamber 211 has, for example, an inlet for supplying the flow path A, an inlet for supplying the fluid B, and an outlet for discharging the bubble dispersion liquid generated by the bubble dispersion.

[0064] The rotor 212 is, for example, gear-shaped. The rotor 212 rotates to disperse bubbles while mixing the fluid A and the fluid B supplied to the processing chamber 211. The generated bubble dispersion liquid is discharged from the processing chamber 211.

[0065] The valve V1 can adjust, for example, the flow rate of fluid A supplied to the processing chamber 211. The valve V2 can adjust, for example, the flow rate of fluid B supplied to the processing chamber 211. The valve V3 can adjust, for example, the flow rate of the air bubble dispersion discharged from the processing chamber 211.

[0066] The carbon dioxide conversion apparatus of the embodiment may appropriately include devices such as a blower, a pump, and a compressor, and these devices may control the flow of fluids including gases and liquids.

[0067] Next, an example of a method for operating the carbon dioxide conversion apparatus according to the embodiment will be described, in which carbon monoxide is produced as a carbon compound.

[0068] In an example of a carbon dioxide conversion method using a carbon dioxide conversion device, in an electrolytic cell stack 101, a cathode supply fluid from a cathode supply fluid supply source is supplied to each flow path 114b via the inlet of each flow path 114b, a supply liquid containing an electrolyte is supplied from a storage tank 102 to each flow path 114a via the inlet of each flow path 114a using a pump 103, and a current or voltage is supplied from a power source. This allows an electrolytic reaction to occur in each of the anodes 111 and cathodes 112.

[0069] The carbon dioxide supplied to each flow path 114b is converted into carbon monoxide and hydroxide ions by an electrolytic reaction at the cathode 112. This reaction is represented by the following formula (8). CO2+H2O+2e - → CO+2OH - (8)

[0070] Water in the electrolyte is converted into hydrogen and hydroxide ions by an electrolytic reaction at the cathode 112. This reaction is represented by the following formula (9). 2H2O+2e - → H2+2OH - (9)

[0071] The hydroxide ions produced by the electrolytic reaction represented by formula (9) react with carbon dioxide to produce carbonate ions and water. This reaction is represented by the following formula (10). CO2+2OH - → CO3 2- +H2O···(10)

[0072] The produced carbonate ions are converted into carbon dioxide and oxygen by an electrolytic reaction at the anode 111. This reaction is represented by the following formula (11). CO3 2- → CO2+0.5O2+2e - (11)

[0073] The produced carbonate ions react with hydroxide ions in an electrolytic reaction at the cathode 112 and are converted to hydrogen carbonate ions. This reaction is represented by the following formula (12). CO2+OH - → HCO3 - (12)

[0074] The carbonate ions produced at the cathode 112 react with water in an electrolytic reaction at the anode 111 and are converted to carbon dioxide and hydroxide ions. This reaction is represented by the following formula (13). CO3 2- +H2O → CO2+2OH - (13)

[0075] The hydrogen carbonate ions produced at the cathode 112 are converted into carbon dioxide and hydroxide ions by an electrolytic reaction at the anode 111. This reaction is represented by the following formula (14). HCO3 - → CO2+OH - (14)

[0076] Unreacted hydroxide ions that are not used in the reaction to produce carbonate ions represented by formula (10) are converted to water and oxygen by an electrolytic reaction at the anode 111. This reaction is represented by the following formula (15). 2OH - → H2O+0.5O2+2e - (15)

[0077] Carbon monoxide and hydrogen produced in the cathode 112 are discharged from each flow channel 114b via the outlet of each flow channel 114b as a cathode discharge fluid CF1 together with unreacted carbon dioxide.

[0078] Carbon dioxide, oxygen, and water produced at the anode 111 are discharged from each flow channel 114a via the outlet of each flow channel 114a as an anode discharge fluid AF1 together with the electrolyte.

[0079] The anode discharge fluid AF1 discharged from the electrolysis cell stack 101 contains oxygen gas, carbon dioxide gas, and a feed liquid. The anode discharge fluid AF1 from the electrolysis cell stack 101 is treated by a gas-liquid separator S1 and separated into an anode discharge fluid AF2 and an anode discharge fluid AF3. The anode discharge fluid AF2 is cooled by a cooler C1, and treated by a gas-liquid separator S2 and separated into an anode discharge fluid AF4 and an anode discharge fluid AF5. The anode discharge fluid AF5 is supplied to the storage tank 102. The anode discharge fluid AF3 is cooled by a cooler C2 and supplied to the storage tank 102.

[0080] The cathode discharge fluid CF1 discharged from the electrolysis cell stack 101 contains carbon monoxide gas, hydrogen gas, and carbon dioxide gas. The cathode discharge fluid CF1 from the electrolysis cell stack 101 is cooled by the cooler C3 and separated into a cathode discharge fluid CF2 and a cathode discharge fluid CF3 by the gas-liquid separator S3. The cathode discharge fluid CF2 contains carbon monoxide gas and carbon dioxide gas. The cathode discharge fluid CF3 contains water. The cathode discharge fluid CF3 is supplied to the storage tank 102 via the valve 104. The liquid contained in the storage tank 102 is supplied to the flow path P1 as an anode supply fluid AF using the pump 103. This allows the liquid contained in the storage tank 102 to be reused.

[0081] Next, an example of a method for recovering unreacted carbon dioxide using the carbon dioxide conversion device of the embodiment will be described. The anode discharge fluid AF4 is dispersed as fine bubbles in the recovery fluid RF12 containing the absorbing liquid by the vortex turbo mixer TM1 (bubble dispersion). The fine bubbles of carbon dioxide are dissolved in the absorbing liquid and absorbed.

[0082] The recovered fluid RF1 from the vortex turbo mixer TM1 is cooled by a cooler C4 and separated into a recovered fluid RF2 and a fluid containing a non-condensed / non-absorbed gas WG1 by a gas-liquid separator S4. The non-condensed / non-absorbed gas WG1 contains, for example, oxygen. The recovered fluid RF2 contains, for example, an absorbing liquid containing carbon dioxide.

[0083] The recovered fluid RF2 from the gas-liquid separator S4 is mixed with the supply fluid SF by the vortex turbo mixer TM2, and the supply fluid SF is dispersed as fine bubbles. The fine bubbles of carbon dioxide are absorbed by the absorbing liquid.

[0084] The recovered fluid RF3 from the vortex turbo mixer TM2 is cooled by a cooler C5 and separated into a recovered fluid RF4 and a fluid containing a non-condensed / non-absorbed gas WG2 by a gas-liquid separator S5. The non-condensed / non-absorbed gas WG2 contains, for example, oxygen and hydrogen. The recovered fluid RF4 contains, for example, an absorbing liquid containing carbon dioxide.

[0085] The recovered fluid RF4 from the gas-liquid separator S5 is preheated by the heat exchanger TE and then heated by the evaporator EP to generate carbon dioxide gas and water vapor.

[0086] The recovered fluid RF5 discharged from the evaporator EP and containing carbon dioxide gas, water vapor, and the absorbing liquid to form a gas-liquid two-phase flow is separated into recovered fluid RF6 and recovered fluid RF7 by the gas-liquid separator S5. The recovered fluid RF6 contains carbon dioxide gas and water vapor. The recovered fluid RF7 contains the absorbing liquid. The carbon dioxide concentration of the recovered fluid RF7 is lower than the carbon dioxide concentration of the recovered fluid RF4.

[0087] The recovered fluid RF6 from the gas-liquid separator S6 is cooled by the cooler C6 and separated into recovered fluid RF8 and recovered fluid RF9 by the gas-liquid separator S7. The recovered fluid RF9 contains carbon dioxide. The carbon dioxide in the recovered fluid RF9 is supplied to the flow path 114b of the electrolysis unit 10 and recycled. The recovered fluid RF8 contains water or water vapor. The recovered fluid RF8 is supplied to the condenser CD via the flow path P25 and recycled.

[0088] The recovered fluid RF7 from the gas-liquid separator S6 is cooled by the heat exchanger TE and condensed by the condenser CD to generate a recovered fluid RF10 containing the absorbing liquid. The recovered fluid RF10 is formed by condensing the recovered fluid RF7 and the recovered fluid RF8.

[0089] The recovered fluid RF10 is mixed with the cathode exhaust fluid CF2 by the vortex turbo mixer TM3, and the cathode exhaust fluid CF2 is dispersed as fine bubbles. The fine bubbles of carbon dioxide are absorbed by the absorbing liquid to form the recovered fluid RF11.

[0090] The recovered fluid RF11 from the vortex turbo mixer TM3 is cooled by a cooler C7 and separated into a recovered fluid RF12 and a non-condensed / non-absorbed gas WG3 by a gas-liquid separator S8. The non-condensed / non-absorbed gas WG3 contains, for example, oxygen and hydrogen. The recovered fluid RF12 is supplied to the vortex turbo mixer TM1.

[0091] The partial pressure of carbon dioxide in the anode discharge fluid AF4 is preferably lower than the partial pressure of carbon dioxide in the supply fluid SF. The partial pressure of carbon dioxide in the supply fluid SF is preferably lower than the partial pressure of carbon dioxide in the cathode discharge fluid CF2. In this way, by treating the fluids in order of carbon dioxide partial pressure from lowest to highest, carbon dioxide can be easily dissolved in the absorption liquid.

[0092] As described above, the carbon dioxide conversion apparatus of the embodiment has a bubble disperser such as a vortex turbo mixer, and the bubble disperser disperses a fluid containing unreacted carbon dioxide into a fluid containing an absorbing liquid to generate a bubble dispersion, and the bubble dispersion is processed to recover carbon dioxide. By dispersing fine carbon dioxide bubbles into the absorbing liquid, the contact area between the carbon dioxide and the absorbing liquid can be increased, thereby improving the dissolution rate of carbon dioxide. Furthermore, by using a vortex turbo mixer, the carbon dioxide conversion apparatus can be made smaller than other mixers, and the dissolution rate of carbon dioxide can be improved. Therefore, the utilization efficiency of carbon dioxide can be improved.

[0093] When the supply fluid SF has a purity high enough to be used as carbon dioxide gas, the supply fluid SF may be supplied to the flow path 114b of the electrolysis unit 10 without passing through the vortex turbo mixer TM2, the cooler C2, and the gas-liquid separator S5. Fig. 6 is a schematic diagram showing another configuration example of the recovery unit 20. As shown in FIG. 6, the recovery section 20 has a vortex turbo mixer TM1, a cooler C4, a gas-liquid separator S4, a heat exchanger TE, an evaporator EP, a gas-liquid separator S6, a cooler C6, a gas-liquid separator S7, a condenser CD, a vortex turbo mixer TM3, a cooler C7, a gas-liquid separator S8, a flow path P14, a flow path P15, a flow path P16, a flow path P20, a flow path P21, a flow path P22, a flow path P23, a flow path P24, a flow path P25, a flow path P26, a flow path P27, a flow path P28, a flow path P29, and a flow path P30, and may not have a vortex turbo mixer TM2, a cooler C5, a gas-liquid separator S5, a flow path P17, a flow path P18, and a flow path P19. The heat exchanger TE may connect the flow path P16 and the flow path P20, and connect the flow path P22 and the flow path P26, and perform heat exchange between these connection points. In the recovery section 20 shown in FIG. 6, the gas-liquid separator S4 is connected to the heat exchanger TE via the flow path P16, and the recovered fluid RF4 from the gas-liquid separator S4 is preheated by the heat exchanger TE and heated by the evaporator EP, generating carbon dioxide gas and water vapor. This allows the recovery fluid RF5 to be generated. Thereafter, the same operation as that of the recovery section 20 shown in FIG. 4 is performed.

[0094] Fig. 7 is a schematic diagram showing another configuration example of the recovery section 20. As shown in Fig. 7, the recovery section 20 has a vortex turbo mixer TM1, a cooler C4, a gas-liquid separator S4, an evaporator EP, a gas-liquid separator S6, a cooler C6, a gas-liquid separator S7, a flow path P14, a flow path P15, a flow path P16, a flow path P21, a flow path P23, and a flow path P24, and may not have a vortex turbo mixer TM2, a cooler C5, a gas-liquid separator S5, a heat exchanger TE, a condenser CD, a vortex turbo mixer TM3, a cooler C7, a gas-liquid separator S8, a flow path P17, a flow path P18, a flow path P19, a flow path P20, a flow path P22, a flow path P25, a flow path P26, a flow path P27, a flow path P28, a flow path P29, and a flow path P30. 7, the gas-liquid separator S4 is connected to the evaporator EP via a flow path P16, and the recovered fluid RF2 from the gas-liquid separator S4 is heated by the evaporator EP to generate carbon dioxide gas and water vapor, thereby generating the recovered fluid RF5.

[0095] The recovered fluid RF5 from the evaporator EP is separated into recovered fluid RF6 and recovered fluid RF7 by the gas-liquid separator S5. The recovered fluid RF6 contains carbon dioxide gas and water vapor. The recovered fluid RF7 contains the absorbing liquid. The carbon dioxide concentration of the recovered fluid RF7 is lower than that of the recovered fluid RF5.

[0096] The recovered fluid RF6 from the gas-liquid separator S6 is cooled by a cooler C6 and separated into a recovered fluid RF8 and a recovered fluid RF9 by a gas-liquid separator S7. The recovered fluid RF9 contains carbon dioxide. The carbon dioxide in the recovered fluid RF9 is supplied to the flow path 114b of the electrolysis unit 10 and recycled. The recovered fluid RF8 contains water or water vapor.

[0097] Fig. 8 is a schematic diagram showing another configuration example of the collection section 20. As shown in Fig. 8, the collection section 20 may include a vortex turbo mixer TM1, a vortex turbo mixer TM2, and a vortex turbo mixer TM3 connected in parallel.

[0098] In FIG. 8, the recovery fluid RF10 from the condenser CD is supplied to each of a vortex turbo mixer TM1, a vortex turbo mixer TM2, and a vortex turbo mixer TM3, which are connected in parallel to the condenser CD.

[0099] A part of the recovered fluid RF10 is mixed with the anode discharge fluid AF4 by the vortex turbo mixer TM1, and the anode discharge fluid AF4 is dispersed as fine bubbles. The fine bubbles of carbon dioxide are absorbed by the absorbing liquid to form the recovered fluid RF1.

[0100] Another part of the recovered fluid RF10 is mixed with the supply fluid SF by the vortex turbo mixer TM2, and the supply fluid SF is dispersed as fine bubbles. The fine bubbles of carbon dioxide are absorbed by the absorbing liquid to form the recovered fluid RF3.

[0101] Another part of the recovered fluid RF10 is mixed with the cathode exhaust fluid CF2 by the vortex turbo mixer TM3, and the cathode exhaust fluid CF2 is dispersed as fine bubbles. The fine bubbles of carbon dioxide are absorbed by the absorbing liquid to form the recovered fluid RF11.

[0102] The recovered fluid RF2 from the gas-liquid separator S4 is mixed with the recovered fluid RF4 via the flow path P16 and the flow path P19. The flow path P16 is connected to, for example, the flow path P19.

[0103] The recovered fluid RF4 from the gas-liquid separator S5 is mixed with the recovered fluid RF2 and the recovered fluid RF12 via the flow path P19. The flow path P19 is connected to, for example, the flow path P16 and the flow path P30.

[0104] The recovered fluid RF12 from the gas-liquid separator S8 is mixed with the recovered fluid RF4 via the flow path P19 and the flow path P30. The flow path P19 is connected to the flow path P30, for example. Other operations are the same as those of the recovery unit 20 shown in Fig. 4. This can improve the utilization efficiency of carbon dioxide, similar to the recovery unit 20 shown in Fig. 4.

[0105] The recovered fluid RF4 from the gas-liquid separator S5 may be branched off, and a part of it may be heated by the recovered fluid RF6 discharged from the gas-liquid separator S6, and then supplied to the evaporator EP or the gas-liquid separator S6. This makes it possible to recover the latent heat and / or sensible heat of the recovered fluid RF6, thereby reducing the heat (energy) required for the evaporator EP.

[0106] Fig. 9 is a schematic diagram showing another configuration example of the recovery section 20. As shown in Fig. 9, the recovery section 20 includes a vortex turbo mixer TM1, a cooler C4, a gas-liquid separator S4, an evaporator EP, a gas-liquid separator S6, a branching device DV, a cooler C6, a gas-liquid separator S7, a vortex turbo mixer TM2, a cooler C5, a gas-liquid separator S5, a heat exchanger TE, a condenser CD, a cooler C7, a gas-liquid separator S8, a vortex turbo mixer TM3, , a turbine TB, a flow path P14, a flow path P15, a flow path P16, a flow path P17, a flow path P18, a flow path P19, a flow path P20, a flow path P21, a flow path P22, a flow path P23, a flow path P24, a flow path P25, a flow path P26, a flow path P27, a flow path P28, a flow path P29, a flow path P30, a flow path P31, a flow path P32, and a flow path P33. Each of the flow paths P31, P32, and P33 can be formed using, for example, piping.

[0107] The splitter DV splits the recovery fluid RF6 from the flow path P23 into recovery fluid RF6A and recovery fluid RF6B. The recovery fluid RF6A is cooled by the cooler C6 via the flow path P31, and separated into recovery fluid RF8 and recovery fluid RF9 by the gas-liquid separator S7. The splitter DV is connected to the gas-liquid separator S6 via the flow path P23, for example, and is provided at the rear of the gas-liquid separator S6.

[0108] The recovered fluid RF6B is supplied to the turbine TB via a flow path P32 connected to the branch DV to drive the turbine TB. The recovered fluid RF13 discharged from the turbine TB via a flow path P33 includes an absorbing liquid containing carbon dioxide. The recovered fluid RF13 is supplied to a condenser CD connected to the turbine TB. The condenser CD forms a recovered fluid RF10 together with the recovered fluid RF7 and the recovered fluid RF8. By supplying a portion of the recovered fluid RF6 to the turbine TB, the external power supplied to operate a device such as a vortex turbo mixer TM can be reduced by using the power generated by the turbine TB.

[0109] The configurations of the collection section 20 shown in FIGS. 4 to 9 can be combined as appropriate.

[0110] The configurations of the above-mentioned embodiments can be applied in combination with each other, and some of them can be replaced. Here, several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0111] 1...carbon dioxide conversion device, 10...electrolysis section, 20...recovery section, 101...electrolysis cell stack, 102...storage tank, 103...pump, 104...valve, 110...carbon dioxide electrolysis cell, 111...anode, 112...cathode, 113...diaphragm, 114...flow path plate, 114a...flow path, 114b...flow path, 211...treatment chamber, 212...rotor, A...fluid, AF...anode supply fluid, AF1...anode discharge fluid, AF2...anode discharge fluid, AF3...anode discharge fluid, AF4...anode discharge fluid, AF5...anode discharge fluid, B...fluid, C1...cooling cooler, C2...cooler, C3...cooler, C4...cooler, C5...cooler, C6...cooler, C7...cooler, CD...condenser, CF...cathode supply fluid, CF1...cathode discharge fluid, CF2...cathode discharge fluid, CF3...cathode discharge fluid, DV...brancher, EP...evaporator, P1...path, P2...path, P3...path, P4...path, P5...path, P6...path, P7...path, P8...path, P9...path, P10...path, P11...path, P12...path, P13...path, P14...path, P15...path, P16...path, P17...path, P18... flow path, P19...flow path, P20...flow path, P21...flow path, P22...flow path, P23...flow path, P24...flow path, P25...flow path, P26...flow path, P27...flow path, P28...flow path, P29...flow path, P30...flow path, P31...flow path, P32...flow path, P33...flow path, RF1...recovered fluid, RF2...recovered fluid, RF3...recovered fluid, RF4...recovered fluid, RF5...recovered fluid, RF6...recovered fluid, RF6A...recovered fluid, RF6B...recovered fluid, RF7...recovered fluid, RF8...recovered fluid, RF9...recovered fluid, RF10...recovered fluid, RF11...recovered fluid, RF 12...recovered fluid, RF13...recovered fluid, S1...gas-liquid separator, S2...gas-liquid separator, S3...gas-liquid separator, S4...gas-liquid separator, S5...gas-liquid separator, S6...gas-liquid separator, S7...gas-liquid separator, S8...gas-liquid separator, SF...supply fluid, TB...turbine, TE...heat exchanger, TM...vortex turbo mixer, TM1...vortex turbo mixer, TM2...vortex turbo mixer, TM3...vortex turbo mixer, V1...valve, V2...valve, V3...valve, WG1...non-condensable / non-absorbed gas, WG2...non-condensable / non-absorbed gas, WG3...non-condensable / non-absorbed gas.

Claims

1. an electrolysis unit that electrolyzes carbon dioxide to generate carbon monoxide; A recovery unit that recovers the carbon dioxide discharged from the electrolysis unit; Equipped with The recovery section includes: A first bubble disperser that disperses the first fluid discharged from the electrolysis unit and containing the carbon dioxide and oxygen into a second fluid containing an absorption liquid to generate a third fluid containing a first bubble dispersion; a first separation section that cools the third fluid and separates the oxygen from the cooled third fluid to generate a fourth fluid including the absorption liquid containing the carbon dioxide; a second separation unit that generates a fifth fluid containing a gas containing the carbon dioxide and water vapor and a liquid containing the absorbing liquid by heating the fourth fluid from the first separation unit to evaporate the absorbing liquid, and separates a sixth fluid containing the gas from the fifth fluid; A third separation section that cools the sixth fluid and separates a seventh fluid containing the carbon dioxide from the cooled sixth fluid; A carbon dioxide conversion apparatus comprising:

2. A second bubble disperser that disperses an eighth fluid discharged from the electrolysis unit and containing the carbon dioxide and the carbon monoxide into a ninth fluid containing the absorption liquid to generate a tenth fluid containing a second bubble dispersion; a fourth separation section for cooling the tenth fluid from the second bubble disperser and separating the carbon monoxide from the tenth fluid to generate an eleventh fluid including the absorption liquid containing the carbon dioxide; Further comprising: The first bubble disperser generates the third fluid by dispersing bubbles from the first fluid into the second fluid including the fourth fluid.

2. The carbon dioxide conversion apparatus of claim 1.

3. A third bubble disperser that generates a thirteenth fluid containing a third bubble dispersion by dispersing a twelfth fluid, which is supplied from a carbon dioxide supply source and contains the carbon dioxide and a gas other than the carbon dioxide, into the fourth fluid from the first separation section; a fifth separation section for cooling the thirteenth fluid from the third bubble disperser and separating the carbon monoxide from the thirteenth fluid to generate a fourteenth fluid including the absorption liquid containing the carbon dioxide; Further comprising: The second separation section heats the fourth fluid including the fourteenth fluid from the fifth separation section to generate the fifth fluid from the fourth fluid, and separates the sixth fluid from the fifth fluid.

2. The carbon dioxide conversion apparatus of claim 1.

4. A second bubble disperser that disperses an eighth fluid discharged from the electrolysis unit and containing the carbon dioxide and the carbon monoxide into a ninth fluid containing the absorption liquid to generate a tenth fluid containing a second bubble dispersion; a fourth separation section for cooling the tenth fluid from the second bubble disperser and separating the carbon monoxide from the tenth fluid to generate an eleventh fluid including the absorption liquid containing the carbon dioxide; A third bubble disperser that generates a thirteenth fluid containing a third bubble dispersion by dispersing a twelfth fluid, which is supplied from a carbon dioxide supply source and contains the carbon dioxide and a gas other than the carbon dioxide, into the fourth fluid from the first separation section; a fifth separation section for cooling the thirteenth fluid from the third bubble disperser and separating the carbon monoxide from the thirteenth fluid to generate a fourteenth fluid including the absorption liquid containing the carbon dioxide; Further comprising: The first bubble disperser generates the third fluid by dispersing bubbles from the first fluid into the second fluid including the fourth fluid; The second separation section heats the fourth fluid including the fourteenth fluid from the fifth separation section to generate the fifth fluid from the fourth fluid, and separates the sixth fluid from the fifth fluid.

2. The carbon dioxide conversion apparatus of claim 1.

5. supplying the seventh fluid from the third separation section to the electrolysis section; 2. The carbon dioxide conversion apparatus of claim 1.

6. The first fluid has a lower partial pressure of carbon dioxide than the eighth fluid; The twelfth fluid has a lower partial pressure of carbon dioxide than the eighth fluid.

5. The carbon dioxide conversion apparatus of claim 4.

7. The second bubble distributor is connected in parallel with the first bubble distributor; The third bubble distributor is connected in parallel with the second bubble distributor.

5. The carbon dioxide conversion apparatus of claim 4.

8. 1. A method for operating a carbon dioxide conversion unit, comprising: The carbon dioxide conversion device comprises: an electrolysis unit that electrolyzes carbon dioxide to generate carbon monoxide; A recovery unit that recovers the carbon dioxide discharged from the electrolysis unit; Equipped with The operating method includes: Using a first bubble disperser provided in the recovery section, the first fluid discharged from the electrolysis section and containing the carbon dioxide and oxygen is bubble-dispersed into a second fluid containing an absorbing liquid to generate a third fluid containing a first bubble dispersion; cooling the third fluid and separating the oxygen from the cooled third fluid to generate a fourth fluid comprising the absorption liquid containing the carbon dioxide; Heating the fourth fluid to evaporate the absorbing liquid, thereby generating a fifth fluid containing a gas containing the carbon dioxide and water vapor and a liquid containing the absorbing liquid, and separating a sixth fluid containing the gas from the fifth fluid; cooling the sixth fluid and separating the seventh fluid comprising carbon dioxide from the cooled sixth fluid; A method for operating a carbon dioxide conversion unit.

9. The operating method includes: Using a second bubble disperser provided in the recovery section, an eighth fluid discharged from the electrolysis section and containing the carbon dioxide and the carbon monoxide is bubble-dispersed into a ninth fluid containing the absorption liquid to generate a tenth fluid containing a second bubble dispersion; cooling the tenth fluid and separating the carbon monoxide from the tenth fluid to generate an eleventh fluid comprising the absorption liquid containing the carbon dioxide; generating the third fluid by dispersing bubbles from the first fluid into the second fluid containing the fourth fluid using the first bubble disperser; A method for operating a carbon dioxide conversion unit according to claim 8.

10. The operating method includes: A third bubble disperser provided in the recovery section is used to disperse a twelfth fluid, which is supplied from a carbon dioxide supply source and contains the carbon dioxide and a gas other than the carbon dioxide, into the fourth fluid, thereby generating a thirteenth fluid containing a third bubble dispersion; cooling the thirteenth fluid and separating the carbon monoxide from the thirteenth fluid to generate a fourteenth fluid comprising the absorption liquid containing the carbon dioxide; heating the fourth fluid including the fourteenth fluid to generate the fifth fluid from the fourth fluid and separating the sixth fluid from the fifth fluid; A method for operating a carbon dioxide conversion unit according to claim 8.

11. The operating method includes: Using a second bubble disperser provided in the recovery section, an eighth fluid discharged from the electrolysis section and containing the carbon dioxide and the carbon monoxide is bubble-dispersed into a ninth fluid containing the absorption liquid to generate a tenth fluid containing a second bubble dispersion; cooling the tenth fluid and separating the carbon monoxide from the tenth fluid to generate an eleventh fluid comprising the absorption liquid containing the carbon dioxide; A third bubble disperser provided in the recovery section is used to disperse a twelfth fluid, which is supplied from a carbon dioxide supply source and contains the carbon dioxide and a gas other than the carbon dioxide, into the fourth fluid, thereby generating a thirteenth fluid containing a third bubble dispersion; cooling the thirteenth fluid and separating the carbon monoxide from the thirteenth fluid to generate a fourteenth fluid comprising the absorption liquid containing the carbon dioxide; Using the first bubble disperser, the first fluid is bubble-dispersed into the second fluid containing the fourth fluid to generate the third fluid; heating the fourth fluid including the fourteenth fluid to generate the fifth fluid from the fourth fluid and separating the sixth fluid from the fifth fluid; A method for operating a carbon dioxide conversion unit according to claim 8.

12. Supplying the seventh fluid to the electrolysis unit; A method for operating a carbon dioxide conversion unit according to claim 8.

13. The first fluid has a lower partial pressure of carbon dioxide than the eighth fluid; The twelfth fluid has a lower partial pressure of carbon dioxide than the eighth fluid. A method for operating a carbon dioxide conversion unit according to claim 11.

14. The second bubble distributor is connected in parallel with the first bubble distributor; The third bubble distributor is connected in parallel with the second bubble distributor. A method for operating a carbon dioxide conversion unit according to claim 11.

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