Electrolytic reaction device and electrolytic reaction method

Abstract

To provide an electrolytic reaction device and an electrolytic reaction method capable of improving efficiency of extracting a carbon-containing compound made by electrolysis.SOLUTION: An electrolytic reaction device 1 comprising means of producing a reduction product of carbon dioxide by applying a voltage between an anode 12 and a cathode 28 to acidify carbonate ion species present in a first carbonic-acid-containing solution including at least one of an alkali metal ion (M+), a carbonate ion (CO32-) and a hydrogen carbonate ion (HCO3-) to produce carbon dioxide (CO2(g)) and further reducing the carbon dioxide (CO2(g)) and water (H2O) to produce a reduction product of carbon dioxide, is characterized by further comprising alkali solution production means of producing an alkali solution by extracting carbon dioxide (CO2(g)) from the first carbonic-acid-containing solution, and carbon dioxide regeneration means of regenerating carbon dioxide (CO2(g)) absorbed in the cathode in a form of carbonate ion species.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electrolytic reaction apparatus and an electrolytic reaction method. [Background technology]

[0002] Carbonate ion species (carbonate ion (CO3 2- ) and bicarbonate ion (HCO3 - There is known a technique for producing carbon monoxide (CO) by direct electrolysis (direct electrolysis) of ammonium nitrate (Ammonium Nitride) (see, for example, Patent Documents 1 to 3 and Non-Patent Documents 1 and 2).

[0003] The electrolytic reactor in this technology is configured, for example, as cathode / catholyte / diaphragm (bipolar membrane, cation exchange membrane) / anode solution / anode, and the electrolyte (catholyte) supplied to the electrolytic reactor is an aqueous solution containing at least one of carbonate ions and bicarbonate ions. Patent Documents 1 and 2 use a 3M KHCO3 aqueous solution as the standard catholyte, while Patent Document 3 uses an aqueous solution generated by bubbling 100% CO2 gas into a 2M KOH aqueous solution (i.e., a 2M CO2-saturated KHCO3 aqueous solution). The products discharged from the electrolytic reactor are hydrogen (H2) and at least one of carbon dioxide (CO2) and carbon monoxide (CO).

[0004] The reaction mechanism is as follows: (1) A solution containing at least one of carbonate ions and hydrogen carbonate ions is passed through the cathode chamber, and a voltage is applied between the cathode and anode separated by a bipolar membrane. This causes hydrogen ions (H + ) is supplied, (2) carbonate ions and bicarbonate ions are chemically converted to neutral carbon dioxide molecules near the cathode, and (3) these carbon dioxide molecules are electrochemically converted to carbon dioxide reduction products such as carbon monoxide.

[0005] This technology achieves a high carbon-containing compound / H2 mass ratio (approximately 10) under conditions where a 2M CO2-saturated KHCO3 aqueous solution or a 3M KHCO3 aqueous solution is supplied in equilibrium with 100% carbon dioxide (CO2) at 1 atmosphere.

[0006] However, under conditions of low carbonate ion concentration (<0.5M) such as in equilibrium with atmospheric carbon dioxide, the carbon-containing compound / H2 mass ratio (<0.16) is low. This is thought to be because the precursor HO of the competing reaction is present in much greater amounts than the precursor COx (carbonate ion) of the desired reaction at the cathode, and is in a state of high activity, so the competing reaction proceeds preferentially.

[0007] Therefore, when supplying an electrolyte solution with a low carbonate ion concentration that is in equilibrium with atmospheric carbon dioxide, there is a demand for an improvement in the carbon-containing compound / H2 substance ratio.

[0008] Furthermore, a technique for producing carbon dioxide (CO2) by electrodialysis of carbonate ion species is known (see, for example, Patent Documents 4 to 12 and Non-Patent Documents 3 to 7).

[0009] The configuration of the electrolytic reactor in this technology is shown, for example, in Figure 3 of Non-Patent Document 6. The electrolyte supplied to the electrolytic reactor in this technology is an aqueous solution or seawater containing at least one of carbonate ions and bicarbonate ions. The products discharged from the electrolytic reactor are hydrogen (H2) and carbon dioxide (CO2).

[0010] The reaction mechanism is as follows: an aqueous solution containing at least one of carbonate ions and bicarbonate ions is passed through the acidification chamber, and a voltage is applied between the cathode and anode; (1) hydrogen (H2) is produced at the cathode, and (2) carbonate ions are converted to neutral carbon dioxide (CO2) in the acidification chamber.

[0011] This technology achieves carbon dioxide and hydrogen production with virtually 100% efficiency using a 0.5M KHCO3 aqueous solution (the ratio of carbon-containing compounds to H2 substances is approximately 2, calculated as the number of additional electrodialysis stacks N=0). Also, even with a very low concentration of 0.125M K2CO3 aqueous solution, an efficiency of approximately 40% is achieved (the ratio of carbon-containing compounds to H2 substances is approximately 0.4, calculated as the number of additional electrodialysis stacks N=0) (see Patent Document 4).

[0012] However, when electrodialysis proceeds, the same amount of water (H2O) is consumed as the hydrogen (H2) produced. For example, when considering continuous operation using this device, the consumption and loss of water, which is the medium, becomes an obstacle to continuous operation.

[0013] Therefore, there is a need to reduce the rate of hydrogen production during electrodialysis operation.

[0014] Thus, in the case of direct electrolytic reduction of carbonate ions, the desired reaction "CO x →CO generation (an example of a CO2 reduction product) x In this case, there is a much greater amount of water (H2O), which is a precursor to the competing reaction "H2O → H2 production," than there is of the desired reaction, and its activity is also higher. Therefore, the competing reaction is more likely to proceed than the desired reaction, and the ratio of carbon-containing compounds to H2 in the gaseous product extracted from the cathode by electrolysis is small.

[0015] In the case of conventional electrodialysis of carbonate ions, the overall reaction when using a K2CO3 aqueous solution is "CO2 (low concentration) + H2O → CO2 (high concentration) + H2 + 1 / 2O2". In other words, the more carbon dioxide (CO2) is extracted, the more water (H2O) is lost in the same amount as the hydrogen (H2) produced at the same time. Also, even if gaseous carbon dioxide (CO2(g)) extracted by a conventional electrodialysis device is simply supplied to the cathode chamber, hydrogen ions (H + ) is supplied in an acidic atmosphere (i.e., an atmosphere suitable for the hydrogen (H2) generation reaction), and since only hydrogen (H2) is generated, an improvement in the extraction efficiency of carbon-containing compounds cannot be expected. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] International Patent Application Publication No. 2019 / 204938 Brochure [Patent Document 2] International Patent Application Publication No. 2021 / 207857 Brochure [Patent Document 3] International Patent Application Publication No. 2020 / 223804 Brochure [Patent Document 4] Patent No. 5848964 [Patent Document 5] Patent No. 5750220 [Patent Document 6] International Patent Application Publication No. 2007 / 018558 Pamphlet [Patent Document 7] Japanese Patent Application Laid-Open No. 2008-100211 [Patent Document 8] International Patent Application Publication No. 2017 / 205044 Brochure [Patent Document 9] International Patent Application Publication No. 2022 / 235708 Brochure [Patent Document 10] Patent No. 5952104 [Patent Document 11] International Patent Application Publication No. 2017 / 205038 Brochure [Patent Document 12] International Patent Application Publication No. 2011 / 142854 Brochure [Non-patent literature]

[0017] [Non-Patent Document 1] http: / / dx.doi.org / 10.1037 / 0021-843X.111.1.14 Tengfei Li, Eric W. Lees, Maxwell Goldman, Danielle A. Salvatore, David M. Weekes, and Curtis P. Berlinguette.

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Outdoor Tools 4

[0018] An object of the present invention is to provide an electrolytic reaction apparatus and an electrolytic reaction method that can improve the efficiency of extracting carbon-containing compounds by electrolysis. [Means for solving the problem]

[0019] The present invention applies a voltage between the anode and the cathode, In the acidification chamber, Alkali metal ions (M + ) and carbonate ions (CO3 2- ) and bicarbonate ion (HCO3 - ), and acidifying carbonate ion species in the first carbonate-containing liquid to form carbon dioxide (CO2(g)), In the cathode chamber, The electrolytic reactor further comprises a means for reducing the carbon dioxide (CO2(g)) and water (HO) to produce a carbon dioxide reduction product, In gas-liquid separators Carbon dioxide (CO2(g)) is extracted from the first carbonated liquid. The separated liquid is then alkalized to hydroxide ions (OH - ) to supply alkali (MOH) and carbon dioxide regeneration means for regenerating carbon dioxide (CO2) absorbed in the form of carbonate ion species at the cathode.

[0020] The electrolytic reactor comprises an anode chamber; an acidification chamber; an alkalinization chamber; a carbon dioxide regeneration chamber; a cathode chamber; an anode disposed between the anode chamber and the acidification chamber in this order from the anode chamber side; a first cation exchange membrane; a second cation exchange membrane disposed between the acidification chamber and the alkalinization chamber; a bipolar membrane disposed between the alkalinization chamber and the carbon dioxide regeneration chamber; an anion exchange membrane disposed between the carbon dioxide regeneration chamber and the cathode chamber in this order from the carbon dioxide regeneration chamber side; the cathode; a first gas-liquid separator; and a second gas-liquid separator. Anode reactants flow into the anode chamber, where they are oxidized by the anode to produce hydrogen ions (H + ) is generated, The first carbonate-containing liquid flows into the acidification chamber, and hydrogen ions (H + ) is supplied to the acidification chamber, and carbonate ion species in the first carbonate-containing liquid are acidified in the acidification chamber to generate carbon dioxide (CO2), The carbon dioxide-containing liquid containing carbon dioxide (CO2) produced in the acidification chamber flows into the second gas-liquid separator, and is separated into gas and liquid in the second gas-liquid separator to extract carbon dioxide (CO2(g)); the gas containing carbon dioxide (CO2(g)) extracted by the second gas-liquid separator flows into the cathode chamber, and a carbon dioxide reduction product is generated in the cathode chamber by a reduction reaction of the gas containing carbon dioxide (CO2(g)) by the cathode; The separated liquid from which carbon dioxide (CO2) has been separated in the second gas-liquid separator flows into the alkalinization chamber, and the alkali metal ions (M + ) is supplied to the alkalinization chamber, and hydroxide ions (OH - ) is supplied to the alkalinizing chamber to generate an alkaline (MOH) solution; The hydroxide ions (OH - Carbonate ion species generated by the interaction of carbon dioxide (CO2) with the bipolar membrane are supplied to the carbon dioxide regeneration chamber, and hydrogen ions (H + ) is supplied to the carbon dioxide regeneration chamber, and the carbonate ion species are acidified in the carbon dioxide regeneration chamber to regenerate carbon dioxide (CO2), The second carbonated liquid containing the carbon dioxide (CO2) regenerated in the carbon dioxide regeneration chamber flows into the first gas-liquid separator, and is separated into gas and liquid in the first gas-liquid separator to extract carbon dioxide (CO2(g)), It is preferable that the gas containing carbon dioxide (CO2(g)) extracted in the first gas-liquid separator flows into the cathode chamber.

[0021] It is preferable that the electrolytic reactor further comprises an additional dialysis zone between the bipolar membrane and the carbon dioxide regeneration chamber, the additional dialysis zone having, in order from the bipolar membrane side, an acidification chamber, a second cation exchange membrane, an alkalinization chamber, an alkalinization chamber, and a bipolar membrane.

[0022] The electrolytic reaction device preferably further comprises a carbon dioxide supplementer for supplementing the produced alkaline solution with carbon dioxide (CO2) to produce a carbonated solution.

[0023] In the electrolytic reaction device, the anode and the first cation exchange membrane are preferably a membrane-electrode assembly in which anode catalyst particles are coated on the first cation exchange membrane.

[0024] In the electrolytic reaction device, the thickness of each of the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber in the direction in which the anode and the cathode face each other is preferably 5 mm or less.

[0025] In the electrolytic reactor, it is preferable that spacers with gaps are inserted into the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber.

[0026] In the electrolytic reactor, the cathode chamber is preferably pressurized.

[0027] In the electrolytic reaction device, the cathode is preferably a cathode catalyst sheet in which nanostructured metal catalyst particles are supported on a substrate having electron conductivity and gas diffusion properties.

[0028] In the electrolytic reaction device, the second carbonate-containing liquid obtained by gas-liquid separation of carbon dioxide (CO2) in the first gas-liquid separator is circulated and supplied to the carbon dioxide regeneration chamber, and the second carbonate-containing liquid circulated and supplied to the carbon dioxide regeneration chamber is preferably an aqueous bicarbonate ion solution containing alkali metal ions saturated with carbon dioxide during operation.

[0029] In the electrolytic reaction device, the alkali metal ions (M + ) concentration is C M [M], the current flowing during electrolysis is I [A], the Faraday constant is F = 96485 C / s, and the number of additional dialysis regions is N, then the total solution delivery rate to the acidification chamber is v all [L / s] is v c =N·I / (F·C M ) as v all ≧0.8v c It is preferable that:

[0030] The present invention applies a voltage between the anode and the cathode, In the acidification chamber, Alkali metal ions (M + ) and carbonate ions (CO3 2- ) and bicarbonate ion (HCO3 - ), and acidifying carbonate ion species in the first carbonate-containing liquid to form carbon dioxide (CO2(g)), In the cathode chamber, The electrolytic reaction method has a function of reducing the carbon dioxide (CO2(g)) and water (HO) to produce a carbon dioxide reduction product, and further comprises: In gas-liquid separators Carbon dioxide (CO2(g)) is extracted from the first carbonated liquid. The separated liquid is then alkalized to hydroxide ions (OH - ) to supply alkali (MOH) This is an electrolytic reaction method in which a liquid is produced and carbon dioxide (CO2) absorbed in the form of carbonate ion species at the cathode is regenerated.

[0031] In the electrolytic reaction method, an electrolytic reaction apparatus is used that includes an anode chamber; an acidification chamber; an alkalinization chamber; a carbon dioxide regeneration chamber; a cathode chamber; an anode that is provided between the anode chamber and the acidification chamber in this order from the anode chamber side; a first cation exchange membrane; a second cation exchange membrane that is provided between the acidification chamber and the alkalinization chamber; a bipolar membrane that is provided between the alkalinization chamber and the carbon dioxide regeneration chamber; an anion exchange membrane that is provided between the carbon dioxide regeneration chamber and the cathode chamber in this order from the carbon dioxide regeneration chamber side; the cathode; a first gas-liquid separator; and a second gas-liquid separator, Anode reactants flow into the anode chamber, where they are oxidized by the anode to produce hydrogen ions (H + ) is generated, The first carbonate-containing liquid flows into the acidification chamber, and hydrogen ions (H + ) is supplied to the acidification chamber, and carbonate ion species in the first carbonate-containing liquid are acidified in the acidification chamber to generate carbon dioxide (CO2), The carbon dioxide-containing liquid containing carbon dioxide (CO2) produced in the acidification chamber flows into the second gas-liquid separator, and is separated into gas and liquid in the second gas-liquid separator to extract carbon dioxide (CO2(g)); the gas containing carbon dioxide (CO2(g)) extracted by the second gas-liquid separator flows into the cathode chamber, and a carbon dioxide reduction product is generated in the cathode chamber by a reduction reaction of the gas containing carbon dioxide (CO2(g)) by the cathode; The separated liquid from which carbon dioxide (CO2) has been separated in the second gas-liquid separator flows into the alkalinization chamber, and the alkali metal ions (M + ) is supplied to the alkalinization chamber, and hydroxide ions (OH - ) is supplied to the alkalinizing chamber to generate an alkaline (MOH) solution; The hydroxide ions (OH -Carbonate ion species generated by the interaction of carbon dioxide (CO2) with the bipolar membrane are supplied to the carbon dioxide regeneration chamber, and hydrogen ions (H + ) is supplied to the carbon dioxide regeneration chamber, and the carbonate ion species are acidified in the carbon dioxide regeneration chamber to regenerate carbon dioxide (CO2), The second carbonated liquid containing the carbon dioxide (CO2) regenerated in the carbon dioxide regeneration chamber flows into the first gas-liquid separator, and is separated into gas and liquid in the first gas-liquid separator to extract carbon dioxide (CO2(g)), It is preferable that the gas containing carbon dioxide (CO2(g)) extracted in the first gas-liquid separator flows into the cathode chamber.

[0032] In the electrolytic reaction method, it is preferable that the electrolytic reaction apparatus further includes an additional dialysis zone between the bipolar membrane and the carbon dioxide regeneration chamber, the additional dialysis zone including, in order from the bipolar membrane side, an acidification chamber, a second cation exchange membrane, an alkalinization chamber, an alkalinization chamber, and a bipolar membrane.

[0033] In the electrolytic reaction method, it is preferable to supplement the produced alkaline solution with carbon dioxide (CO2) to produce a carbonated solution.

[0034] In the electrolytic reaction method, the anode and the first cation exchange membrane are preferably a membrane-electrode assembly in which anode catalyst particles are coated on the first cation exchange membrane.

[0035] In the electrolytic reaction method, the thickness of each of the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber in the direction in which the anode and the cathode face each other is preferably 5 mm or less.

[0036] In the electrolytic reaction method, it is preferable that spacers with gaps are inserted into the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber.

[0037] In the electrolytic reaction method, it is preferable that the cathode chamber is pressurized.

[0038] In the electrolytic reaction method, the cathode is preferably a cathode catalyst sheet in which nanostructured metal catalyst particles are supported on a substrate having electron conductivity and gas diffusion properties.

[0039] In the electrolytic reaction method, it is preferable that the second carbonate-containing liquid obtained by gas-liquid separation of carbon dioxide (CO2) in the first gas-liquid separator is circulated and supplied to the carbon dioxide regeneration chamber, and that the second carbonate-containing liquid circulated and supplied to the carbon dioxide regeneration chamber is an aqueous bicarbonate ion solution containing alkali metal ions saturated with carbon dioxide during operation.

[0040] In the electrolytic reaction method, the alkali metal ions (M + ) concentration is C M [M], the current flowing during electrolysis is I [A], the Faraday constant is F = 96485 C / s, and the number of additional dialysis regions is N, then the total solution delivery rate to the acidification chamber is v all [L / s] is v c =N·I / (F·C M ) as v all ≧0.8v c It is preferable that: [Effects of the Invention]

[0041] The present invention can provide an electrolytic reaction apparatus and an electrolytic reaction method that can improve the efficiency of extracting carbon-containing compounds by electrolysis. [Brief explanation of the drawings]

[0042] [Figure 1] 1 is a schematic diagram showing an example of an electrolytic reaction device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing an example of a spacer that may be provided in the electrolytic reaction device according to an embodiment of the present invention. [Figure 3]This is a gas chromatogram (solid line) of gas collected downstream of the cathode chamber when constant-current electrolysis was performed with 100% Ar supplied at 2 cc / min in Example 1. (a) shows the H region, (b) shows the CO region, and (c) shows the CO region. For comparison, a gas chromatogram (dotted line) of air collected on the same day of the experiment is also shown. [Figure 4] 1 is a graph comparing carbon-containing compounds and H2 ratios produced by electrolysis. [Figure 5] This is a gas chromatogram (solid line) of gas collected downstream of the cathode chamber when constant current electrolysis was performed with 100% CO supplied at 2 cc / min in Example 2. (a) shows the H region, and (b) shows the CO region. For comparison, a gas chromatogram (dotted line) of air collected on the same day of the experiment is also shown. DETAILED DESCRIPTION OF THE INVENTION

[0043] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes an embodiment of the present invention. The embodiment is an example of implementing the present invention, and the present invention is not limited to the embodiment.

[0044] The electrolytic reaction device according to this embodiment generates alkali metal ions (M + ) and carbonate ions (CO3 2- ) and bicarbonate ion (HCO3 - ), to produce carbon dioxide (CO2(g)), and then reduce the carbon dioxide (CO2(g)) with water (H2O) to produce a carbon dioxide reduction product. The electrolytic reaction device according to this embodiment further comprises alkaline solution production means that extracts carbon dioxide (CO2(g)) from the first carbonate-containing solution to produce an alkaline solution with a low dissolved carbon concentration, and carbon dioxide regeneration means that regenerates carbon dioxide (CO2) absorbed in the form of carbonate ion species at the cathode.

[0045] The electrolytic reaction apparatus and electrolytic reaction method according to this embodiment can improve the extraction efficiency of carbon-containing compounds (particularly carbon dioxide reduction products) by electrolysis.

[0046] An example of the electrolytic reaction apparatus according to this embodiment is shown in FIG. 1, and its configuration will be described.

[0047] The electrolytic reactor 1 shown in FIG. 1 comprises an anode chamber 10; an acidification chamber 16; an alkalinization chamber 20; a carbon dioxide regeneration chamber 24; a cathode chamber 30; an anode 12 disposed between the anode chamber 10 and the acidification chamber 16, in this order from the anode chamber 10 side; a first cation exchange membrane 14; a second cation exchange membrane 18 disposed between the acidification chamber 16 and the alkalinization chamber 20; a bipolar membrane 22 including a cation exchange membrane 22a and an anion exchange membrane 22b, disposed between the alkalinization chamber 20 and the carbon dioxide regeneration chamber 24; an anion exchange membrane 26 disposed between the carbon dioxide regeneration chamber 24 and the cathode chamber 30, in this order from the carbon dioxide regeneration chamber 24 side; a cathode 28; a first gas-liquid separator 40; and a second gas-liquid separator 38.

[0048] In the electrolytic reactor 1, an anode reactant supply line 52 extending from an anode reactant supply source 34 is connected to the inlet of the anode chamber 10. A pump for supplying the anode reactant may be installed in the anode reactant supply line 52. An anode reactant discharge line 54 is connected to the outlet of the anode chamber 10. The anode reactant discharge line 54 may be connected to the anode reactant supply source 34 to circulate the anode reactant. A first carbonated liquid supply line 68 extending from the first carbonated liquid supply source 36 is connected to the inlet of the acidification chamber 16. A pump 44 for supplying and circulating the first carbonated liquid may be installed in the first carbonated liquid supply line 68. The outlet of the acidification chamber 16 is connected to the liquid inlet of the second gas-liquid separator 38 by a carbon dioxide-containing liquid supply line 70. The liquid outlet of the second gas-liquid separator 38 is connected to the inlet of the alkalinization chamber 20 by a separated liquid supply line 72. A gas supply line 56 may be connected to the gas inlet of the second gas-liquid separator 38 via an on-off valve, or the outlet of the gas supply source 37 may be connected by the gas supply line 56. An alkaline liquid discharge line 74 is connected to the outlet of the alkalinization chamber 20. The gas outlet of the second gas-liquid separator 38 and the gas inlet of the first gas-liquid separator 40 are connected by a gas supply line 58. A pump 46 may be installed in the gas supply line 58 to promote the removal of carbon dioxide-containing gas from the first gas-liquid separator 40 and the second gas-liquid separator 38 and the supply of the removed carbon dioxide-containing gas. The gas outlet of the first gas-liquid separator 40 and the inlet of the cathode chamber 30 are connected by a gas supply line 64. Here, the gas supply flow does not have to be from the gas supply source 37 to the second gas-liquid separator 38, to the first gas-liquid separator 40, to the cathode chamber 30, but may be from the gas supply source 37 to the first gas-liquid separator 40, to the second gas-liquid separator 38, to the cathode chamber 30. Also, a portion of the gas that has passed through two gas-liquid separators (i.e., the second gas-liquid separator 38 and the first gas-liquid separator 40) may be supplied to the cathode chamber 30, and the remainder may be returned to the gas supply source 37. A cathode reactant discharge line 66 is connected to the outlet of the cathode chamber 30. A liquid outlet of the first gas-liquid separator 40 and an inlet of the carbon dioxide regeneration chamber 24 are connected by a second carbonated liquid supply line 60.A pump 42 for supplying and circulating the second carbonated liquid may be installed in the second carbonated liquid supply line 60. The outlet of the carbon dioxide regeneration chamber 24 and the liquid inlet of the first gas-liquid separator 40 are connected by the second carbonated liquid supply line 62. A power supply unit 48 is connected to the anode 12 and the cathode 28 by electrical connection or the like, so that a voltage can be applied between the anode 12 and the cathode 28.

[0049] The operation of the electrolytic reactor 1 and the electrolytic reaction will be described with reference to FIG.

[0050] A voltage is applied between the anode 12 and the cathode 28 by a power supply 48. Anode reactants flow from an anode reactant supply source 34 into the anode chamber 10 through an anode reactant supply line 52. In the anode chamber 10, hydrogen ions (H + ) is generated.

[0051] Alkali metal ions (M + ) and carbonate ions (CO3 2- ) and bicarbonate ion (HCO3 - ) flows from the first carbonated liquid supply source 36 through the first carbonated liquid supply line 68, using a pump 44 as needed, into the acidification chamber 16, and hydrogen ions (H + ) through the first cation exchange membrane 14 or the bipolar membrane 22 to generate hydrogen ions (H + ) is supplied to the acidification chamber 16 through the second cation exchange membrane 18, and the carbonate ion species (carbonate ion (CO3 2- ) and bicarbonate ion (HCO3 - ) is acidified to produce carbon dioxide (CO2).

[0052] The carbon dioxide-containing liquid containing carbon dioxide (CO2) produced in the acidification chamber 16 flows into the second gas-liquid separator 38 through the carbon dioxide-containing liquid supply line 70, where gas and liquid are separated and carbon dioxide (CO2(g)) is extracted.

[0053] The gas containing carbon dioxide (CO2(g)) extracted by the second gas-liquid separator 38 is passed through the gas supply line 58, using the pump 46 as needed, via the first gas-liquid separator 40, and then through the gas supply line 64 to flow into the cathode chamber 30, where the gas containing carbon dioxide (CO2(g)) undergoes a reduction reaction at the cathode 28 to produce carbon dioxide reductants. The carbon dioxide reductants are discharged through the cathode reactant discharge line 66.

[0054] The separated liquid from which carbon dioxide (CO2) has been separated in the second gas-liquid separator 38 flows into the alkalinization chamber 20 through the separated liquid supply line 72, and the alkali metal ions (M + ) is supplied to the alkalinization chamber 20 through the second cation exchange membrane 18, and the hydroxide ions (OH - ) is supplied to the alkalinization chamber 20, where an alkaline (MOH) solution is produced. The alkaline (MOH) solution is discharged through an alkaline solution discharge line 74.

[0055] The hydroxide ions (OH - Carbonate ion species generated by the interaction of carbon dioxide (CO2) with the anion exchange membrane 26 are supplied to the carbon dioxide regeneration chamber 24, and hydrogen ions (H + ) is supplied to the carbon dioxide regeneration chamber 24, where the carbonate ion species are acidified to regenerate carbon dioxide (CO2).

[0056] The second carbonated liquid containing carbon dioxide (CO2) regenerated in the carbon dioxide regeneration chamber 24 flows into the first gas-liquid separator 40 through the second carbonated liquid supply line 62, where gas and liquid are separated and carbon dioxide (CO2(g)) is extracted.

[0057] Gas containing carbon dioxide (CO2(g)) extracted in the first gas-liquid separator 40 flows into the cathode chamber 30 through a gas supply line 64. The second carbonated liquid from which carbon dioxide (CO2) has been separated in the first gas-liquid separator 40 is circulated and supplied to the carbon dioxide regeneration chamber 24 through a second carbonated liquid supply line 60 using a pump 42 as needed.

[0058] As described above, in the electrolytic reactor 1, by applying a voltage between the anode 12 and the cathode 28, alkali metal ions (M + ) and carbonate ions (CO3 2- ) and bicarbonate ion (HCO3 - ), carbonate ion species in the first carbonate-containing liquid containing at least one of the following are acidified to form carbon dioxide (CO2(g)), and then in the cathode chamber 30, the carbon dioxide (CO2(g)) is reduced with water (H2O) to produce a carbon dioxide reduction product. Furthermore, in the second gas-liquid separator 38 and the alkalinization chamber 20, carbon dioxide (CO2(g)) is extracted from the first carbonate-containing liquid to produce an alkaline liquid with a low dissolved carbon concentration, and in the carbon dioxide regeneration chamber 24, the carbon dioxide (CO2) absorbed in the form of carbonate ion species in the cathode is regenerated.

[0059] In the electrolytic reactor 1, the anode 12, the cathode 28, the acidification chamber 16, the anode chamber 10, the cathode chamber 30, the anode reactant supply source 34, the first carbonate-containing liquid supply source 36, the power supply 48, etc., apply a voltage between the anode and the cathode to generate alkali metal ions (M + ) and carbonate ions (CO3 2- ) and bicarbonate ion (HCO3 -), to produce carbon dioxide (CO2(g)), and then to reduce the carbon dioxide (CO2(g)) with water (H2O) to produce a carbon dioxide reduction product. The second gas-liquid separator 38, the alkalinization chamber 20, etc. function as alkaline solution production means that extracts carbon dioxide (CO2(g)) from the first carbonate-containing liquid to produce an alkaline solution. The carbon dioxide regeneration chamber 24, etc. function as carbon dioxide regeneration means that regenerates carbon dioxide (CO2) absorbed in the form of carbonate ion species in the cathode.

[0060] The electrolytic reactor 1 may further include one or more additional dialysis regions 32 between the bipolar membrane 22 and the carbon dioxide regeneration chamber 24, each of which includes, in order from the bipolar membrane 22 side, the acidification chamber 16, the second cation exchange membrane 18, the alkalinization chamber 20, and an acidification chamber similar to the bipolar membrane 22, a second cation exchange membrane, an alkalinization chamber, and a bipolar membrane. Here, the number of additional dialysis regions 32 is defined as N (N is an integer equal to or greater than 0). When N=0, no additional dialysis region 32 is provided, and the bipolar membrane 22 and the carbon dioxide regeneration chamber 24 are adjacent to each other.

[0061] When the electrolytic reactor 1 further includes an additional dialysis zone 32, as shown in FIG. 1 , a first carbonated liquid supply line 78 branching off from the first carbonated liquid supply line 68 from the first carbonated liquid supply source 36 is connected to the inlet of the acidification compartment of the additional dialysis zone 32. A carbon dioxide-containing liquid supply line 80 connected to the outlet of the acidification compartment of the additional dialysis zone 32 is connected to the middle of the carbon dioxide-containing liquid supply line 70. A separated liquid supply line 82 branching off from the separated liquid supply line 72 from the second gas-liquid separator 38 is connected to the inlet of the alkalinization compartment of the additional dialysis zone 32. An alkaline liquid discharge line 84 connected to the outlet of the alkalinization compartment of the additional dialysis zone 32 is connected to the middle of the alkaline liquid discharge line 74.

[0062] When the current flowing through the electrolytic reactor is constant, the additional dialysis region 32 can further increase the amount of hydrogen ions (H +) can be increased according to the number N of additional dialysis regions 32, thereby increasing the carbon dioxide (CO2) extraction rate (i.e., the amount of CO2 extracted per unit time) throughout the electrolysis reactor.

[0063] The electrolytic reaction device 1 may further include a carbon dioxide replenisher 50 that replenishes the alkaline liquid produced in the alkalinization chamber 20 with carbon dioxide (CO2) to produce a carbonated liquid. In this case, as shown in FIG. 1 , the outlet of the alkalinization chamber 20 and the inlet of the carbon dioxide replenisher 50 may be connected by an alkaline liquid discharge line 74. The outlet of the carbon dioxide replenisher 50 and the inlet of the first carbonated liquid supply source 36 may be connected by a carbonated liquid supply line 76. Then, the carbon dioxide replenisher 50 replenishes the alkaline liquid produced in the alkalinization chamber 20 with carbon dioxide (CO2) to produce a carbonated liquid, which may be circulated to the first carbonated liquid supply source 36 as the first carbonated liquid.

[0064] The thickness of each of the acidification chamber 16, alkalinization chamber 20, and carbon dioxide regeneration chamber 24 in the direction in which the anode 12 and cathode 28 face each other is preferably 5 mm or less, and more preferably 2 mm or less, in order to reduce ion conduction resistance.

[0065] To improve contact between the cathode catalyst sheet (cathode 28) described below and the conductive housing on the cathode side and between the anode 12 and the conductive housing on the anode side to reduce electronic conduction resistance, and to improve contact between the cathode catalyst sheet (cathode 28) and the anion exchange membrane 26 to reduce ionic conduction resistance, it is preferable to insert spacers with gaps in each of the acidification chamber 16, alkalinization chamber 20, and carbon dioxide regeneration chamber 24. Furthermore, to promote acidification of carbonate ion species and the discharge of air bubbles, the spacers are preferably spacers 86 having serpentine channels 88 engraved therein, as shown in FIG. 2 .

[0066] In conventional electrodialysis, hydrogen is assumed to be generated at the cathode. Therefore, the ion exchange membrane adjacent to (opposing) the cathode chamber is designed to trap hydrogen ions (H+ ) is supplied to the cathode chamber through a cation exchange membrane (inside a bipolar membrane) (see Figure 3 in Non-Patent Document 6). An electrolyte is circulated and supplied to the cathode chamber. It is possible to attempt electrolytic reduction by simply bubbling gaseous carbon dioxide (CO2(g)) extracted by electrodialysis into the cathode chamber. However, in the highly acidic atmosphere described above, hydrogen generation becomes dominant and carbon dioxide reduction does not substantially occur.

[0067] Therefore, in order to suppress the by-production of hydrogen at the cathode and to preferentially promote the reduction of carbon dioxide, it is desirable to create a cathode reaction environment that is suitable for the reduction of carbon dioxide.

[0068] A suitable cathode reaction environment can be said to be (1) an environment rich in carbon dioxide, and (2) an alkaline atmosphere in which hydrogen generation is difficult. In the electrolytic reaction device and electrolytic reaction method according to this embodiment, in order to form a suitable cathode reaction environment, (1) a gas containing carbon dioxide is supplied to the cathode chamber 30, and (2) a configuration is adopted in which the cathode 28 is adjacent to the anion exchange membrane 26 in order to maintain an alkaline atmosphere. With this configuration, hydroxide ions (OH - ) reacts with the supplied carbon dioxide (CO2) to form carbonate ion species, which can cause a secondary problem of leaking into an adjacent chamber through the anion exchange membrane 26. To solve this secondary problem and enable efficient use of carbon dioxide, the electrolytic reaction device and electrolytic reaction method according to this embodiment are provided with a carbon dioxide regeneration chamber 24 sandwiched between the anion exchange membrane 26 and the bipolar membrane 22. Even if carbon dioxide leaks from the cathode chamber 30 to the carbon dioxide regeneration chamber 24 in the form of carbonate ion species, it is possible to acidify the carbonate ion species to generate protons (H + ) is supplied from the bipolar membrane 22, so that carbon dioxide can be regenerated.

[0069] When gaseous carbon dioxide (CO2(g)) is electrolytically reduced at a high conversion rate with this configuration, it becomes difficult to maintain the above-mentioned "(1) carbon dioxide-rich environment" due to the penetration of water and electrolyte from the carbon dioxide regeneration chamber 24. To solve this problem, it is preferable to adjust the pressure inside the cathode chamber 30 by pressurizing it (for example, to about 2 atmospheres).

[0070] Furthermore, in order to promote the formation of the above-mentioned "(1) carbon dioxide-rich environment," it is preferable to use, as the cathode 28, a cathode catalyst sheet that supports nanostructured metal catalyst particles (e.g., Au, Ag, Zn, Cu, etc.) on a substrate with a large surface area that exhibits good electronic conductivity and gas diffusivity.

[0071] The alkali metal ions M contained in the first carbonate-containing liquid supplied to the acidification chamber 16 + The concentration of M [M], the current flowing during electrolysis is I [A], the Faraday constant is F = 96485 C / s, and the number of additional dialysis regions is N, then the total solution flow rate to the acidification chamber is v all [L / s] is v c =N·I / (F·C M ) as v all ≧0.8v c It is preferable that:

[0072] The electrolytic reaction device and electrolytic reaction method according to this embodiment can improve the ratio of "(amount of C substance in carbon-containing compound) / (amount of H substance)" extracted from the downstream side of the cathode of the electrolytic reaction device compared to direct electrolysis and electrodialysis, which are conventional techniques for producing carbon-containing compounds from carbonate-containing liquids.

[0073] Furthermore, for example, if the carbon dioxide reduction product is carbon monoxide (CO), by setting the H2 generation reaction ratio to 0% and the carbon dioxide (CO2) reduction to carbon monoxide (CO) generation reaction ratio to approach 100%, it is possible to extract and generate carbon-containing compounds (CO2, CO) with almost no consumption or loss of water (H2O).

[0074] This is because, unlike direct electrolysis, the electrolytic reaction apparatus and electrolytic reaction method according to this embodiment are able to selectively generate the desired reaction "CO x This is thought to be because, compared to electrodialysis, the electrolytic reaction device and electrolytic reaction method according to this embodiment can cause not only the "H evolution reaction" but also the "CO reduction and CO generation reaction" as the cathode reaction.

[0075] Furthermore, the electrolytic reaction device and electrolytic reaction method according to this embodiment can eliminate the problem of CO absorption and CO leakage to the anode side (accompanied by mixing with anode-generated O or anode reactants) that occurs in electrolytic reactors (where the cathode-anode diaphragm is an anion exchange membrane) that reduce gas (CO) at the cathode.

[0076] This is because hydrogen ions (H + ) is supplied to the atmosphere, acidifying (reactivating) it and allowing carbon dioxide to be regenerated.

[0077] A detailed comparison between the electrolytic reaction apparatus and electrolytic reaction method according to this embodiment and the conventional electrodialysis method will be described below.

[0078] When the electrolysis reaction proceeds, an electrolytic oxidation reaction occurs at the anode, and an electrolytic reduction reaction occurs at the cathode, causing a certain amount of current (a certain amount of electrons per unit time) to flow. In the electrodialysis chamber (acidification chamber, alkalinization chamber) where the acidification or alkalinization reaction proceeds, the amount of cations (H + , M + ), anion (OH - , HCO3 - , CO3 2- ) flows in the direction facing the cathode and anode (normal direction of the electrode surface).

[0079] Here, we consider a potassium carbonate (K2CO3) aqueous solution as the carbonate-containing liquid to be supplied to the electrolytic reactor. 2- The reaction that activates CO3 2- +2H + →H2O+CO2⇔xCO3 2- +2xH + →xH2O+xCO2 In the aqueous solution supply, x [mol] of carbonate ions (CO3 2- ) is supplied, 2x [mol] of H is generated as the electrolytic treatment reaction progresses. + The above acidification (activation) reaction will produce x [mol] of carbon dioxide (CO2).

[0080] 2x [mol] hydrogen ions (H + ) is supplied, 2x [mol] electrons (e - ) is consumed or produced. Here, we focus on the cathode. In the case of conventional electrodialysis, only the hydrogen (H2) evolution reaction proceeds. That is, 2H2O+2e - →H2+2OH - ⇔2H + +2e - →H2⇔2xH + +2xe - →xH2 Therefore, 2x [mol] hydrogen ions (H + ) is supplied, x [mol] of hydrogen (H2) is produced at the cathode. Therefore, in the case of conventional electrodialysis, the ratio of (amount of C substance of carbon-containing compound) / (amount of H2 substance) is x / x=1.

[0081] In the electrolytic reaction device and electrolytic reaction method according to this embodiment, in addition to the hydrogen (H2) generation reaction, the carbon dioxide (CO2) reduction reaction can also proceed at the cathode. -), 50% (i.e. x [mol]) is used for the hydrogen (H2) generation reaction and 50% for the carbon dioxide (CO2) reduction reaction. As for carbon dioxide (CO2), if the following carbon monoxide (CO) generation reaction proceeds, carbon dioxide (CO2) decreases by 0.5x [mol] and carbon monoxide (CO) increases by 0.5x [mol]. CO2+2H2O+2e - →CO+2OH - ⇔CO2+2H + +2e - →CO+H2O⇔0.5xCO2+xH + +xe - →0.5xCO+0.5xH2O Therefore, in the case of the electrolytic reaction apparatus and electrolytic reaction method according to this embodiment, the ratio "(amount of C substance of carbon-containing compound) / (amount of H substance)" is (x-0.5x+0.5x) / 0.5x=1 / 0.5=2. Under the same conditions, when the substance amount ratio is "1" in the conventional electrodialysis method, it becomes "2" in the electrolytic reaction apparatus and electrolytic reaction method according to this embodiment. This shows that the electrolytic reaction apparatus and electrolytic reaction method according to this embodiment enable the extraction of a larger amount of carbon-containing compound.

[0082] In the electrolytic reaction apparatus and electrolytic reaction method according to this embodiment, even when the number of additional electrodialysis layers N is 0, when an electrolyte solution having a composition of K2CO3 (C / K=1 / 2) to KHCO3 (C / K=1) is supplied, the hydrogen (H2) generation reaction ratio can be brought close to 0% and the carbon dioxide (CO2) reduction reaction ratio can be brought close to 100%, thereby making it possible to convert the overall reaction from 2CO2 (400 ppm) to CO2 ((1-x) bar) + CO(x bar) + 1 / 2O2, and to extract and produce carbon-containing compounds with almost no consumption or loss of water (H2O).

[0083] The anode 12 may be made of, for example, a metal oxide catalyst such as an iridium oxide (IrO2) catalyst or a ruthenium oxide (RuO2) catalyst.

[0084] The cathode 28 may be, for example, a cathode catalyst sheet in which nanostructured metal catalyst particles (e.g., Au, Ag, Zn, Cu, etc.) are supported on a large surface area substrate that exhibits good electronic conductivity and gas diffusivity.

[0085] Examples of the first cation exchange membrane 14 and the second cation exchange membrane 18 that can be used include fluorine-based sulfonic acid cation exchange membranes such as Nafion (registered trademark) (manufactured by DuPont) and Forblue (registered trademark) (manufactured by AGC), and hydrocarbon-based cation exchange membranes such as Selemion (registered trademark) (manufactured by AGC), Neosepta (registered trademark) (manufactured by Astom), and Fumasep (manufactured by Fumatech).

[0086] The anode 12 and the first cation exchange membrane 14 adjacent to the anode 12 are preferably a membrane-electrode assembly (MEA) in which anode catalyst particles (e.g., iridium oxide (IrO) or the like) are coated on the first cation exchange membrane 14, which has high proton conductivity, in order to reduce ion conduction resistance.

[0087] As the anion exchange membrane 26, for example, PiperION manufactured by Versogen, Sustainion manufactured by Dioxide Materials, or the like can be used.

[0088] The bipolar membrane 22 includes a cation exchange membrane 22a and an anion exchange membrane 22b. As the bipolar membrane 22, for example, Fumasep manufactured by Fumatech, Neosepta manufactured by Astom, or the like can be used.

[0089] The anode reactant supplied to the anode chamber 10 is oxidized at the anode 12 to generate hydrogen ions (H +There are no particular limitations on the material as long as it can supply the hydrogen. Examples include humidified air or inert gases (nitrogen (N2), rare gases) at room temperature, hydrogen (H2), gases containing hydrogen atoms in the molecule (e.g., methane (CH4), ethane (C2H6), ethylene (C2H4), ammonia (NH3), etc.), aqueous electrolyte solutions, and water containing water-soluble anode reactants (e.g., methanol (CH3OH), ethanol (C2H5OH), hydrazine (N2H4), etc.).

[0090] The anode reactant supply 34 is, for example, a reservoir that stores the anode reactant.

[0091] The first carbonate-containing liquid supplied to the acidification chamber 16 contains, for example, alkali metal ions (M + ) and bicarbonate ions (HCO3 - ) and carbonate ions (CO3 2- ) and at least one of the following. Examples include aqueous solutions containing alkali metal bicarbonates or alkali metal carbonates, such as lithium bicarbonate (LiHCO3), sodium bicarbonate (NaHCO3), potassium bicarbonate (KHCO3), sodium carbonate (Na2CO3), potassium carbonate (K2CO3), and cesium bicarbonate (CsHCO3). The alkali metal ion concentration in the electrolyte is preferably in the range of 0.1 M to 3 M, for example, in order to improve the electrolysis rate and enable the electrolysis to be carried out continuously for a long period of time. Since this aqueous solution does not directly contact the electrodes, the first carbonate-containing liquid supplied to the acidification chamber 16 may contain, in addition to the above ions, other alkali metal ions, alkaline earth metal ions, transition metal ions, halide ions, sulfate ions, nitrate ions, phosphate ions, and carboxylate ions that may be contained in groundwater, industrial water, lake water, seawater, and exhaust gas contact water.

[0092] The first carbonated liquid supply source 36 is, for example, a storage tank that stores the first carbonated liquid.

[0093] The second carbonate-containing liquid circulated and supplied to the carbon dioxide regeneration chamber 24 is preferably an aqueous bicarbonate ion solution containing alkali metal ions saturated with carbon dioxide (CO2) during operation (steady state) (for example, a 1 to 3 M CO2 saturated KHCO3 aqueous solution).

[0094] The gas supply source 37 is, for example, a gas supply device that supplies gas to the first gas-liquid separator 40 and the second gas-liquid separator .

[0095] The gas supplied to the first gas-liquid separator 40 and the second gas-liquid separator 38 is, for example, an inert gas (for example, nitrogen (N2), rare gas), 100% carbon dioxide (CO2) gas, or a mixture thereof.

[0096] The first gas-liquid separator 40 and the second gas-liquid separator 38 are, for example, a gas-liquid separation tank that separates a gas containing the product from a liquid (e.g., an electrolyte solution) from which the gas product has been removed, or a module equipped with a separation membrane.

[0097] The carbon dioxide compensation device 50 is, for example, a carbon dioxide compensation tank that supplies gas containing carbon dioxide (CO2) to an alkaline solution to produce a carbonated solution.

[0098] The carbon dioxide reduction products obtained in the cathode chamber 30 include, for example, carbon monoxide (CO), ethylene (C2H4), methane (CH4), methanol (CH3OH), ethanol (C2H5OH), and propanol (C3H7OH).

[0099] The present specification includes the following embodiments. [1] By applying a voltage between the anode and the cathode, alkali metal ions (M + ) and carbonate ions (CO3 2- ) and bicarbonate ion (HCO3 - ), and further reducing the carbon dioxide (CO2(g)) with water (HO) to produce a carbon dioxide reduction product, moreover, an alkaline solution generating means for extracting carbon dioxide (CO2(g)) from the first carbonate-containing liquid to generate an alkaline solution; a carbon dioxide regeneration means for regenerating carbon dioxide (CO2) absorbed in the cathode in the form of carbonate ion species; An electrolytic reactor comprising:

[0100] [2] The electrolytic reactor according to [1], an anode chamber; an acidification chamber; an alkalinization chamber; a carbon dioxide regeneration chamber; a cathode chamber; the anode and a first cation exchange membrane, which are provided between the anode chamber and the acidification chamber in this order from the anode chamber side; a second cation exchange membrane disposed between the acidification chamber and the alkalinization chamber; a bipolar membrane disposed between the alkalinization chamber and the carbon dioxide regeneration chamber; an anion exchange membrane provided between the carbon dioxide regeneration chamber and the cathode chamber in this order from the carbon dioxide regeneration chamber side; and the cathode. a first gas-liquid separator; a second gas-liquid separator; Equipped with Anode reactants flow into the anode chamber, where they are oxidized by the anode to produce hydrogen ions (H + ) is generated, The first carbonate-containing liquid flows into the acidification chamber, and hydrogen ions (H + ) is supplied to the acidification chamber, and carbonate ion species in the first carbonate-containing liquid are acidified in the acidification chamber to generate carbon dioxide (CO2), The carbon dioxide-containing liquid containing carbon dioxide (CO2) produced in the acidification chamber flows into the second gas-liquid separator, and is separated into gas and liquid in the second gas-liquid separator to extract carbon dioxide (CO2(g)); the gas containing carbon dioxide (CO2(g)) extracted by the second gas-liquid separator flows into the cathode chamber, and a carbon dioxide reduction product is generated in the cathode chamber by a reduction reaction of the gas containing carbon dioxide (CO2(g)) by the cathode; The separated liquid from which carbon dioxide (CO2) has been separated in the second gas-liquid separator flows into the alkalinization chamber, and the alkali metal ions (M + ) is supplied to the alkalinization chamber, and hydroxide ions (OH - ) is supplied to the alkalinizing chamber to generate an alkaline (MOH) solution; The hydroxide ions (OH - Carbonate ion species generated by the interaction of carbon dioxide (CO2) with the bipolar membrane are supplied to the carbon dioxide regeneration chamber, and hydrogen ions (H + ) is supplied to the carbon dioxide regeneration chamber, and the carbonate ion species are acidified in the carbon dioxide regeneration chamber to regenerate carbon dioxide (CO2), The second carbonated liquid containing the carbon dioxide (CO2) regenerated in the carbon dioxide regeneration chamber flows into the first gas-liquid separator, and is separated into gas and liquid in the first gas-liquid separator to extract carbon dioxide (CO2(g)), The gas containing carbon dioxide (CO2(g)) extracted in the first gas-liquid separator flows into the cathode chamber.

[0101] [3] The electrolytic reactor according to [2], The electrolytic reactor further comprises an additional dialysis zone between the bipolar membrane and the carbon dioxide regeneration chamber, the additional dialysis zone comprising, in order from the bipolar membrane side, an acidification chamber, a second cation exchange membrane, an alkalinization chamber, an alkalinization chamber, and a bipolar membrane.

[0102] [4] The electrolytic reactor according to [2] or [3], The electrolytic reaction apparatus further includes a carbon dioxide supplementer that supplements the generated alkaline solution with carbon dioxide (CO2) to generate a carbonated solution.

[0103] [5] The electrolytic reaction apparatus according to any one of [2] to [4], the anode and the first cation exchange membrane are a membrane-electrode assembly in which anode catalyst particles are coated on the first cation exchange membrane;

[0104] [6] The electrolytic reaction apparatus according to any one of [2] to [5], an electrolytic reaction device, wherein the thickness of each of the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber in the direction in which the anode and the cathode face each other is 5 mm or less;

[0105] [7] The electrolytic reactor according to any one of [2] to [6], An electrolytic reactor, wherein spacers with gaps are inserted into the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber.

[0106] [8] The electrolytic reaction apparatus according to any one of [2] to [7], The cathode chamber is pressurized.

[0107] [9] The electrolytic reaction apparatus according to any one of [2] to [8], The electrolytic reaction device, wherein the cathode is a cathode catalyst sheet in which nanostructured metal catalyst particles are supported on a substrate having electron conductivity and gas diffusivity.

[0108]

[10] The electrolytic reactor according to any one of [2] to [9], The second carbonated liquid obtained by gas-liquid separation of carbon dioxide (CO2) in the first gas-liquid separator is circulated and supplied to the carbon dioxide regeneration chamber, The second carbonate-containing liquid circulated and supplied to the carbon dioxide regeneration chamber is an aqueous hydrogen carbonate ion solution containing alkali metal ions saturated with carbon dioxide during operation of the electrolytic reaction device.

[0109]

[11] The electrolytic reactor according to [3], The alkali metal ions (M + ) concentration is C M [M], the current flowing during electrolysis is I [A], the Faraday constant is F = 96485 C / s, and the number of additional dialysis regions is N, then the total solution delivery rate to the acidification chamber is v all [L / s] is v c =N·I / (F·C M ) as v all ≧0.8v c This is an electrolytic reactor.

[0110]

[12] By applying a voltage between the anode and the cathode, alkali metal ions (M + ) and carbonate ions (CO3 2- ) and bicarbonate ion (HCO3 - ), and further reducing the carbon dioxide (CO2(g)) with water (HO) to produce a carbon dioxide reduction product, moreover, extracting carbon dioxide (CO2(g)) from the first carbonate-containing liquid to produce an alkaline liquid; An electrolytic reaction method in which carbon dioxide (CO2) absorbed in the form of carbonate ion species at the cathode is regenerated.

[0111]

[13] The electrolytic reaction method according to

[12] , an anode chamber; an acidification chamber; an alkalinization chamber; a carbon dioxide regeneration chamber; a cathode chamber; the anode and a first cation exchange membrane, which are provided between the anode chamber and the acidification chamber in this order from the anode chamber side; a second cation exchange membrane disposed between the acidification chamber and the alkalinization chamber; a bipolar membrane disposed between the alkalinization chamber and the carbon dioxide regeneration chamber; an anion exchange membrane provided between the carbon dioxide regeneration chamber and the cathode chamber in this order from the carbon dioxide regeneration chamber side; and the cathode. a first gas-liquid separator; a second gas-liquid separator; An electrolytic reactor comprising: Anode reactants flow into the anode chamber, where they are oxidized by the anode to produce hydrogen ions (H + ) is generated, The first carbonate-containing liquid flows into the acidification chamber, and hydrogen ions (H + ) is supplied to the acidification chamber, and carbonate ion species in the first carbonate-containing liquid are acidified in the acidification chamber to generate carbon dioxide (CO2), The carbon dioxide-containing liquid containing carbon dioxide (CO2) produced in the acidification chamber flows into the second gas-liquid separator, and is separated into gas and liquid in the second gas-liquid separator to extract carbon dioxide (CO2(g)); the gas containing carbon dioxide (CO2(g)) extracted by the second gas-liquid separator flows into the cathode chamber, and a carbon dioxide reduction product is generated in the cathode chamber by a reduction reaction of the gas containing carbon dioxide (CO2(g)) by the cathode; The separated liquid from which carbon dioxide (CO2) has been separated in the second gas-liquid separator flows into the alkalinization chamber, and the alkali metal ions (M + ) is supplied to the alkalinization chamber, and hydroxide ions (OH - ) is supplied to the alkalinizing chamber to generate an alkaline (MOH) solution; The hydroxide ions (OH - Carbonate ion species generated by the interaction of carbon dioxide (CO2) with the bipolar membrane are supplied to the carbon dioxide regeneration chamber, and hydrogen ions (H + ) is supplied to the carbon dioxide regeneration chamber, and the carbonate ion species are acidified in the carbon dioxide regeneration chamber to regenerate carbon dioxide (CO2), The second carbonated liquid containing the carbon dioxide (CO2) regenerated in the carbon dioxide regeneration chamber flows into the first gas-liquid separator, and is separated into gas and liquid in the first gas-liquid separator to extract carbon dioxide (CO2(g)), The electrolytic reaction method, wherein the gas containing carbon dioxide (CO2(g)) extracted in the first gas-liquid separator flows into the cathode chamber.

[0112]

[14] The electrolytic reaction method according to

[13] , the electrolytic reactor further comprises an additional dialysis zone between the bipolar membrane and the carbon dioxide regeneration chamber, the additional dialysis zone having, in this order from the bipolar membrane side, an acidification chamber, a second cation exchange membrane, an alkalinization chamber, an alkalinization chamber, and a bipolar membrane.

[0113]

[15] The electrolytic reaction method according to

[13] or

[14] , An electrolytic reaction method in which carbon dioxide (CO2) is added to the alkaline solution produced to produce a carbonated solution.

[0114]

[16] The electrolytic reaction method according to any one of

[13] to

[15] , The electrolytic reaction method, wherein the anode and the first cation exchange membrane are a membrane-electrode assembly in which anode catalyst particles are coated on the first cation exchange membrane.

[0115]

[17] The electrolytic reaction method according to any one of

[13] to

[16] , The electrolytic reaction method, wherein the thickness of each of the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber in the direction in which the anode and the cathode face each other is 5 mm or less.

[0116]

[18] The electrolytic reaction method according to any one of

[13] to

[17] , An electrolytic reaction method, wherein spacers with gaps are inserted into the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber.

[0117]

[19] The electrolytic reaction method according to any one of

[13] to

[18] , The cathode chamber is pressurized.

[0118]

[20] The electrolytic reaction method according to any one of

[13] to

[19] , The electrolytic reaction method, wherein the cathode is a cathode catalyst sheet in which nanostructured metal catalyst particles are supported on a substrate having electron conductivity and gas diffusion properties.

[0119]

[21] The electrolytic reaction method according to any one of

[13] to

[20] , The second carbonated liquid obtained by gas-liquid separation of carbon dioxide (CO2) in the first gas-liquid separator is circulated and supplied to the carbon dioxide regeneration chamber, The electrolytic reaction method, wherein the second carbonate-containing liquid circulated and supplied to the carbon dioxide regeneration chamber is an aqueous bicarbonate ion solution containing alkali metal ions saturated with carbon dioxide during operation.

[0120]

[22]

[14] The electrolytic reaction method according to The alkali metal ions (M + ) concentration is C M [M], the current flowing during electrolysis is I [A], the Faraday constant is F = 96485 C / s, and the number of additional dialysis regions is N, then the total solution delivery rate to the acidification chamber is v all [L / s] is v c =N·I / (F·C M ) as v all ≧0.8v c The electrolytic reaction method is as follows. [Example]

[0121] EXAMPLES The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0122] Example 1 [Electrolytic treatment under slow Ar supply conditions from a gas source (CO2, CO, H2 generation)] The electrolytic reactor 1 shown in FIG. 1 had the following components.

[0123] (System Configuration) Pump 46: CO2 extraction and supply promotion pump Gas supply source 37: 100% Ar gas is supplied at 2 ccm using a mass flow controller. Number of additional dialysis areas: N=0 Discharge of alkaline solution: No carbon dioxide compensator 50, only discharge of alkaline solution through alkaline solution discharge line 74 First carbonated liquid supply source 36: A 0.1M KHCO3 aqueous solution is supplied at 1 mL / min using a liquid supply pump (pump 44). Anode reactant source 34: 10 ccm of room temperature humidified Ar using a mass flow controller

[0124] (Experimental conditions) Anode 12, first cation exchange membrane 14: proton conductive membrane coated with IrO2 nanoparticles (cation exchange membrane, DuPont Nafion (registered trademark) N115) Second cation exchange membrane 18: DuPont Nafion® N115 Bipolar membrane 22: Fumatech Fumasep FBM bipolar membrane Anion exchange membrane 26: Versogen PiperION-A60-HCO3 Cathode 28: SGL Carbon Sigracet 39BB gas diffusion layer spray-coated with a catalyst ink made from gold-loaded carbon particles and Nafion solution. ·Electrode area: 6.25cm 2 Electrolyte (first carbonate-containing solution) supplied to the acidification chamber 16: 0.1M KHCO3 aqueous solution Electrolyte (second carbonate-containing liquid) circulated and supplied to the carbon dioxide regeneration chamber 24: 1M KHCO3 aqueous solution (delivered at 5 mL / min using a liquid delivery pump (pump 42)) ·First gas-liquid separator 40: Small liquid storage tank Second gas-liquid separator 38: 3M MM-1 x 5.5 separation membrane module

[0125] Electrolysis was performed under constant current conditions (40 mA), and the gases discharged from the downstream side of the cathode chamber 30 were collected using a gas-tight syringe and identified and quantified using a gas chromatograph (GC) (Shimadzu Corporation, GC-2014). H2, CO, and CO2 were detected as gases produced by the electrolysis reactor (see Figure 3). The faradaic efficiencies for H2 and CO2 production during the cathode reaction, calculated from the gas concentrations quantified by GC and the current values, were 3.1% and 27.3%, respectively (the sum is likely not 100% due to detection error and side reactions such as the reduction of dissolved atmospheric O2). It was found that CO2 could be converted to CO using the electrolysis reactor configuration shown in Figure 1 and under low-rate Ar supply conditions. Furthermore, it was found that when the only CO source introduced into the electrolysis reactor is a low-C-concentration carbonate solution, the faradaic efficiency of CO generation can be increased compared to the conventional direct electrolysis of carbonate ions (the faradaic efficiency of CO generation in a 0.5 M KHCO aqueous solution in Non-Patent Document 1 is approximately 14%).

[0126] The ratios of carbon-containing compounds and H produced by treatment in the electrolytic reactor were calculated and compared with those of CO production by direct electrolysis of carbonate ion species and CO production by electrodialysis (see Figure 4). In Figure 4, "Example 1" represents the results of Example 1 (0.1 M KHCO aqueous solution, N = 0). "Other" in "Example 1" represents the difference between the sum of the Faradaic efficiencies for H and CO production (30.4%) and 100%, i.e., the ratio when it is assumed that two-electron transfer reaction gas production occurs with the current (Faraday efficiency 69.6%) flowing for the progress of electrolytic reduction reactions other than H and CO production (the ratio of "other" decreases when the number of reaction electrons is greater than 2). Even if we assume that all "others" are H generation (assuming a minimum CO → CO conversion), the ratio of "carbon-containing compounds (CO + CO) / H substance amount" could be improved by using the electrolytic reaction apparatus and reaction mechanism of the example (in Example 1, it was ≧2.52 compared to 0.16 for direct electrolysis of carbonate ions and 2 for conventional electrodialysis (theoretical value)). Thus, it was found that the extraction efficiency of carbon-containing compounds could be improved.

[0127] In Figure 4, the CO generation by direct electrolysis refers to the results for a 0.5 M KHCO3 aqueous solution in Figure 2 of Non-Patent Document 1 (a 0.1 M KHCO3 aqueous solution equivalent to Example 1 was used as a substitute because no data was given for this solution).

[0128] Regarding CO2 generation by electrodialysis in Figure 4, since there are no results under conditions equivalent to those in Example 1, Figure 4 shows the theoretical maximum CO2 / H2 ratio when using an electrodialysis device equivalent to that in Example 1 (0.1M KHCO3 aqueous solution, number of additional electrodialysis stacks N = 0). That is, in the case of a KHCO3 aqueous solution, 2 mol e - , H + By the transfer of 2 mol of CO2 (HCO3 - +H + →H2O+CO2) and 1 mol of H2 (2H + +2e - Therefore, CO2 is 2 / (1+2)=66.7% and H2 is 1 / (1+2)=33.3%.

[0129] In Figure 4, for Example 1, as described above, the ratio is shown as "others" when it is assumed that two-electron transfer reaction gas production occurs at the difference (69.6%) between the sum of the Faraday efficiencies for H2 and CO production (30.4%) and 100%. This is the same number of reaction electrons as for H2 and CO production, and is the minimum number of reaction electrons for gas production. When the number of reaction electrons is greater than 2, the relative proportion of "others" decreases. Therefore, from the perspective of (CO2 + CO) production, assuming "others" to be two-electron transfer reaction gas production and H2 production assumes the maximum amount as the gas production proportion (amount of substance) of the "others" component.

[0130] <Example 2> [Electrolytic treatment under low CO2 supply rate from gas source (CO and H2 generation)] 1, the electrolysis system had the following components: The gas supplied by the gas supply source 37 was changed from "100% Ar" in Example 1 to "100% CO2."

[0131] (System Configuration) Pump 46: CO2 extraction and supply promotion pump Gas supply source 37: 100% CO2 is supplied at 2 ccm using a mass flow controller. Number of additional dialysis areas: N=0 Discharge of alkaline solution: No carbon dioxide compensator 50, only discharge of alkaline solution through alkaline solution discharge line 74 First carbonated liquid supply source 36: A 0.1M KHCO3 aqueous solution is supplied at 1 mL / min using a liquid supply pump (pump 44). Anode reactant source 34: 10 ccm of room temperature humidified Ar using a mass flow controller

[0132] (Experimental conditions) Anode 12, first cation exchange membrane 14: proton conductive membrane coated with IrO2 nanoparticles (cation exchange membrane, DuPont Nafion (registered trademark) N115) Second cation exchange membrane 18: DuPont Nafion® N115 Bipolar membrane 22: Fumatech Fumasep FBM bipolar membrane Anion exchange membrane 26: Versogen PiperION-A60-HCO3 Cathode 28: SGL Carbon Sigracet 39BB gas diffusion layer spray-coated with a catalyst ink made from gold-loaded carbon particles and Nafion solution. ·Electrode area: 6.25cm 2 Electrolyte (first carbonate-containing solution) supplied to the acidification chamber 16: 0.1M KHCO3 aqueous solution Electrolyte (second carbonate-containing liquid) circulated and supplied to the carbon dioxide regeneration chamber 24: 1M KHCO3 aqueous solution (delivered at 5 mL / min using a liquid delivery pump (pump 42)) ·First gas-liquid separator 40: Small liquid storage tank Second gas-liquid separator 38: 3M MM-1 x 5.5 separation membrane module

[0133] Electrolysis was performed under constant current conditions (40 mA), and gases discharged from the downstream side of the cathode chamber 30 were collected using a gas-tight syringe and identified and quantified using gas chromatography (GC). H and CO were detected as gases produced by the electrolysis (see Figure 5). The faradaic efficiencies for H and CO production calculated from the gas concentrations quantified by GC and the current values ​​were 7.6% and 84.8%, respectively (the sum is not 100%, likely due to detection error and side reactions such as the reduction of dissolved atmospheric O). It was found that CO could be converted to CO while suppressing H production under the electrolysis reactor configuration shown in Figure 1 and low CO supply rates. Operation of this electrolysis reactor with additional CO supplied from an external CO source and circulating excess CO produced by adding electrodialysis stacks (N≧1) corresponds to Example 2. Under these CO supply conditions, consumption and loss of the reaction medium HO during electrolysis can be further reduced.

[0134] As described above, the electrolytic reaction apparatus and electrolytic reaction method of the present invention were able to improve the efficiency of extracting carbon-containing compounds by electrolysis. [Explanation of symbols]

[0135] 1 Electrolysis reactor, 10 Anode chamber, 12 Anode, 14 First cation exchange membrane, 16 Acidification chamber, 18 Second cation exchange membrane, 20 Alkalization chamber, 22 Bipolar membrane, 22a Cation exchange membrane, 22b, 26 Anion exchange membrane, 24 Carbon dioxide regeneration chamber, 28 Cathode, 30 Cathode chamber, 32 Additional dialysis area, 34 Anode reactant supply source, 36 First carbonated liquid supply source, 37 Gas supply source, 38 Second gas-liquid separator, 40 First gas-liquid separator, 42, 44, 46 Pump, 48 Power supply unit, 50 Carbon dioxide compensator, 52 Anode reactant supply line, 54 Anode reactant discharge line, 56, 58, 64 Gas supply line, 60 Second carbonated liquid supply line, 62 Second carbonated liquid supply line, 66 Cathode reactant discharge line, 68, 78 First carbonated liquid supply line, 70, 80 carbon dioxide-containing liquid supply line, 72, 82 separated liquid supply line, 74, 84 alkaline liquid discharge line, 76 carbonated liquid supply line, 86 spacer, 88 serpentine flow path.

Claims

1. By applying a voltage between the anode and the cathode, alkali metal ions (M ＋ ) and carbonate ions (CO ３ ２－ ) and bicarbonate ion (HCO ３ － ) and at least one of the carbonate ion species in the first carbonate-containing liquid, and converting the carbonate ion species into carbon dioxide (CO ２ (g)), and then in the cathode chamber, the carbon dioxide (CO ２ (g)) and water (H ２ 1. An electrolytic reactor having a means for reducing carbon dioxide and oxygen to produce a carbon dioxide reduction product, moreover, In the gas-liquid separator, carbon dioxide (CO ２ (g)) is extracted and the separated liquid is supplied with hydroxide ions (OH − ) in an alkalinizing chamber to generate an alkaline (MOH) liquid; Carbon dioxide (CO ) absorbed in the form of carbonate ion species at the cathode ２ a carbon dioxide regeneration means for regenerating the carbon dioxide; An electrolytic reaction device comprising:

2. 2. The electrolytic reactor according to claim 1, an anode chamber; an acidification chamber; an alkalinization chamber; a carbon dioxide regeneration chamber; a cathode chamber; the anode and a first cation exchange membrane, which are provided between the anode chamber and the acidification chamber in this order from the anode chamber side; a second cation exchange membrane disposed between the acidification chamber and the alkalinization chamber; a bipolar membrane disposed between the alkalinization chamber and the carbon dioxide regeneration chamber; an anion exchange membrane provided between the carbon dioxide regeneration chamber and the cathode chamber in this order from the carbon dioxide regeneration chamber side; and the cathode. a first gas-liquid separator; a second gas-liquid separator; Equipped with Anode reactants flow into the anode chamber, where they are oxidized by the anode to produce hydrogen ions (H ＋ ) is generated, The first carbonate-containing liquid flows into the acidification chamber, and hydrogen ions (H ＋ ) is supplied to the acidification chamber, and carbonate ion species in the first carbonate-containing liquid are acidified in the acidification chamber to produce carbon dioxide (CO ２ ) is generated, Carbon dioxide (CO ２ The carbon dioxide-containing liquid containing carbon dioxide (CO ) flows into the second gas-liquid separator, and is separated into gas and liquid in the second gas-liquid separator. ２ (g)) is taken out, The carbon dioxide (CO ２ (g)) flows into the cathode chamber, and the carbon dioxide (CO ２ (g)) is reduced by the cathode to generate a carbon dioxide reduction product; The second gas-liquid separator separates carbon dioxide (CO ２ ) is separated from the gas and liquid, and the separated liquid flows into the alkalinization chamber, and the alkali metal ions (M ＋ ) is supplied to the alkalinization chamber, and hydroxide ions (OH － ) is supplied to the alkalinizing chamber to generate an alkaline (MOH) solution, The hydroxide ions (OH － ) and carbon dioxide (CO ２ ) generated by the interaction with the hydrogen ions (H ＋ ) is supplied to the carbon dioxide regeneration chamber, and the carbonate ion species is acidified in the carbon dioxide regeneration chamber to produce carbon dioxide (CO ２ ) plays, The carbon dioxide (CO ２ The second carbonated liquid containing carbon dioxide (CO ) flows into the first gas-liquid separator, and is separated into gas and liquid in the first gas-liquid separator. ２ (g)) is taken out, The carbon dioxide (CO ２ (g)) into the cathode chamber.

3. 3. The electrolytic reactor according to claim 2, an additional dialysis zone between the bipolar membrane and the carbon dioxide regeneration chamber, the additional dialysis zone comprising, in order from the bipolar membrane side, an acidification chamber, a second cation exchange membrane, an alkalinization chamber, an alkalinization chamber, and a bipolar membrane.

4. 3. The electrolytic reactor according to claim 2, The generated alkaline solution is added with carbon dioxide (CO ２ The electrolytic reaction apparatus further comprises a carbon dioxide replenisher for replenishing the carbon dioxide to produce a carbonated liquid.

5. 3. The electrolytic reactor according to claim 2, The electrolytic reaction device is characterized in that the anode and the first cation exchange membrane are a membrane-electrode assembly in which anode catalyst particles are coated on the first cation exchange membrane.

6. 3. The electrolytic reactor according to claim 2, 10. An electrolytic reaction device, wherein the thickness of each of the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber in the direction in which the anode and the cathode face each other is 5 mm or less.

7. 3. The electrolytic reactor according to claim 2, An electrolytic reaction apparatus, characterized in that spacers with gaps are inserted into the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber.

8. 3. The electrolytic reactor according to claim 2, Electrolytic reactor characterized in that the cathode chamber is pressurized.

9. 3. The electrolytic reactor according to claim 2, The electrolytic reaction device is characterized in that the cathode is a cathode catalyst sheet in which metal catalyst particles having a nanostructure are supported on a substrate having electron conductivity and gas diffusivity.

10. 3. The electrolytic reactor according to claim 2, In the first gas-liquid separator, carbon dioxide (CO ２ The second carbonated liquid obtained by gas-liquid separation of the carbon dioxide gas is circulated and supplied to the carbon dioxide regeneration chamber, The electrolytic reaction device is characterized in that the second carbonate-containing liquid circulated and supplied to the carbon dioxide regeneration chamber is an aqueous bicarbonate ion solution containing alkali metal ions saturated with carbon dioxide during operation.

11. 4. The electrolytic reactor according to claim 3, The alkali metal ions (M ＋ ) concentration is C Ｍ [M], the current flowing during electrolysis is I [A], the Faraday constant is F = 96485 C / s, and the number of additional dialysis regions is N, the total solution delivery rate to the acidification chamber is v ａｌｌ [L / s] is v ｃ = N.I. / (F.C. Ｍ ) as v ａｌｌ ≧0.8v ｃ An electrolytic reaction device characterized by:

12. By applying a voltage between the anode and the cathode, alkali metal ions (M ＋ ) and carbonate ions (CO ３ ２－ ) and bicarbonate ion (HCO ３ － ) and at least one of the carbonate ion species in the first carbonate-containing liquid, and converting the carbonate ion species into carbon dioxide (CO ２ (g)), and then in the cathode chamber, the carbon dioxide (CO ２ (g)) and water (H ２ O) to produce a carbon dioxide reduction product, moreover, In the gas-liquid separator, carbon dioxide (CO ２ (g)) is taken out, and hydroxide ions (OH − ) are supplied to the separated liquid obtained in an alkalinizing chamber to generate an alkaline (MOH) liquid; Carbon dioxide (CO ) absorbed in the form of carbonate ion species at the cathode ２ ) An electrolytic reaction method characterized by:

13. The electrolytic reaction method according to claim 12, an anode chamber; an acidification chamber; an alkalinization chamber; a carbon dioxide regeneration chamber; a cathode chamber; the anode and a first cation exchange membrane, which are provided between the anode chamber and the acidification chamber in this order from the anode chamber side; a second cation exchange membrane disposed between the acidification chamber and the alkalinization chamber; a bipolar membrane disposed between the alkalinization chamber and the carbon dioxide regeneration chamber; an anion exchange membrane provided between the carbon dioxide regeneration chamber and the cathode chamber in this order from the carbon dioxide regeneration chamber side; and the cathode. a first gas-liquid separator; a second gas-liquid separator; An electrolytic reactor comprising: Anode reactants flow into the anode chamber, where they are oxidized by the anode to produce hydrogen ions (H ＋ ) is generated, The first carbonate-containing liquid flows into the acidification chamber, and hydrogen ions (H ＋ ) is supplied to the acidification chamber, and carbonate ion species in the first carbonate-containing liquid are acidified in the acidification chamber to produce carbon dioxide (CO ２ ) is generated, Carbon dioxide (CO ２ The carbon dioxide-containing liquid containing carbon dioxide (CO ) flows into the second gas-liquid separator, and is separated into gas and liquid in the second gas-liquid separator. ２ (g)) is taken out, The carbon dioxide (CO ２ (g)) flows into the cathode chamber, and the carbon dioxide (CO ２ (g)) is reduced by the cathode to generate a carbon dioxide reduction product; The second gas-liquid separator separates carbon dioxide (CO ２ ) is separated from the gas and liquid, and the separated liquid flows into the alkalinization chamber, and the alkali metal ions (M ＋ ) is supplied to the alkalinization chamber, and hydroxide ions (OH － ) is supplied to the alkalinizing chamber to generate an alkaline (MOH) solution, The hydroxide ions (OH － ) and carbon dioxide (CO ２ ) generated by the interaction with the hydrogen ions (H ＋ ) is supplied to the carbon dioxide regeneration chamber, and the carbonate ion species is acidified in the carbon dioxide regeneration chamber to produce carbon dioxide (CO ２ ) plays, The carbon dioxide (CO ２ The second carbonated liquid containing carbon dioxide (CO ) flows into the first gas-liquid separator, and is separated into gas and liquid in the first gas-liquid separator. ２ (g)) is taken out, The carbon dioxide (CO ２ (g)) into the cathode chamber.

14. The electrolytic reaction method according to claim 13, The electrolytic reaction method is characterized in that the electrolytic reactor further comprises an additional dialysis zone between the bipolar membrane and the carbon dioxide regeneration chamber, the additional dialysis zone including, in order from the bipolar membrane side, an acidification chamber, a second cation exchange membrane, an alkalinization chamber, an alkalinization chamber, and a bipolar membrane.

15. The electrolytic reaction method according to claim 13, The generated alkaline solution is added with carbon dioxide (CO ２ ) to produce a carbonated liquid.

16. The electrolytic reaction method according to claim 13, The electrolytic reaction method is characterized in that the anode and the first cation exchange membrane are a membrane-electrode assembly in which anode catalyst particles are coated on the first cation exchange membrane.

17. The electrolytic reaction method according to claim 13, 10. An electrolytic reaction method, wherein the thickness of each of the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber in the direction in which the anode and the cathode face each other is 5 mm or less.

18. The electrolytic reaction method according to claim 13, An electrolytic reaction method, characterized in that spacers with gaps are inserted into the acidification chamber, the alkalinization chamber, and the carbon dioxide regeneration chamber.

19. The electrolytic reaction method according to claim 13, An electrolytic reaction method, characterized in that the cathode chamber is pressurized.

20. The electrolytic reaction method according to claim 13, The electrolytic reaction method is characterized in that the cathode is a cathode catalyst sheet in which metal catalyst particles having a nanostructure are supported on a substrate having electron conductivity and gas diffusion properties.

21. The electrolytic reaction method according to claim 13, In the first gas-liquid separator, carbon dioxide (CO ２ The second carbonated liquid obtained by gas-liquid separation of the carbon dioxide gas is circulated and supplied to the carbon dioxide regeneration chamber, The electrolytic reaction method according to claim 1, wherein the second carbonate-containing liquid circulated and supplied to the carbon dioxide regeneration chamber is an aqueous bicarbonate ion solution containing alkali metal ions saturated with carbon dioxide during operation.

22. The electrolytic reaction method according to claim 14, The alkali metal ions (M ＋ ) concentration is C Ｍ [M], the current flowing during electrolysis is I [A], the Faraday constant is F = 96485 C / s, and the number of additional dialysis regions is N, the total solution delivery rate to the acidification chamber is v ａｌｌ [L / s] is v ｃ = N.I. / (F.C. Ｍ ) as v ａｌｌ ≧0.8v ｃ An electrolytic reaction method characterized by:

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