Carbon Dioxide Conversion System

Abstract

One aspect of the present invention provides a carbon dioxide conversion system that includes an anode chamber in which a carbon dioxide reduction reaction takes place, and a cathode chamber in which a hydrogen oxidation reaction takes place.

Description

[Technical field]

[0001] The present invention relates to a carbon dioxide conversion system, and more particularly to a carbon dioxide conversion system that is energy efficient, minimizes the need for hydrogen purification equipment, and can produce a high-purity product. [Background technology]

[0002] Recently, the impact of global climate change has become more pronounced. As a result, countries around the world are making efforts to reduce the various substances that cause global warming. Carbon dioxide in particular is attracting the greatest attention, as emissions have increased sharply with industrial development.

[0003] Large amounts of carbon dioxide are generated at thermal power plants, steel mills, cement factories, and other facilities that use fossil fuels. The technology to capture, store, and process the carbon dioxide generated at such facilities is called CCS (Carbon Capture and Storage). Active research is being conducted on CCU (Carbon Capture and Utilization), a technology that not only stores carbon dioxide but also recycles it through a conversion process. CCUS (Carbon Capture Utilization and Storage), which combines these technologies, is an essential technology for achieving carbon neutrality, the goal of the United Nations Framework Convention on Climate Change.

[0004] Such carbon dioxide utilization methods can be broadly divided into non-conversion methods, which use carbon dioxide usefully in itself, and conversion methods, which convert carbon dioxide into useful compounds and recycle it. Carbon dioxide conversion technologies can be classified into chemical conversion technologies and biological conversion technologies. Among these, chemical conversion technologies include thermocatalytic chemical conversion, electrochemical conversion, photochemical conversion, etc., depending on the technical characteristics.

[0005] Electrochemical conversion technology is a technology in which carbon dioxide is supplied to the aqueous solution of an electrolysis device and reduced by electrical energy to convert it into an organic compound. Depending on the type of electrode material and reaction conditions, organic compounds such as formic acid, methane, ethane, carbon monoxide, oxalic acid, and synthetic gas can be selectively produced. This electrochemical conversion technology can be carried out under normal temperature and pressure conditions. In addition, the raw materials required for the reaction are simply electrolyte and carbon dioxide, and if the electrolyte is recycled, conversion can be carried out without emitting chemical substances. In addition, the system is simple and has the characteristics of being modularized, and research and development is being conducted in various methods.

[0006] In the electrolysis device, hydrogen gas is generated as a side reaction and is mixed with the unreacted carbon dioxide, so the hydrogen must be separated in order to recover and recycle the unreacted carbon dioxide.

[0007] In the past, gas-liquid separators, membranes, compressors, etc. were used to separate the generated by-product hydrogen from the unreacted carbon dioxide. However, there are problems with the use of these facilities, such as increased costs and significant space restrictions. In addition, separating hydrogen and carbon dioxide with a membrane is inefficient, and the actual recovery / recirculation rate of carbon dioxide is insufficient. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention is made to solve the above-mentioned problems of the conventional technology, and an object of the present invention is to provide a carbon dioxide conversion system capable of producing a high-purity product with excellent energy efficiency by oxidizing by-product hydrogen in a process of converting carbon dioxide through an electrochemical reduction reaction. [Means for solving the problem]

[0009] One aspect of the present invention provides a carbon dioxide conversion system that includes an anode chamber in which a carbon dioxide reduction reaction takes place, and a cathode chamber in which a hydrogen oxidation reaction takes place. In one embodiment, the fuel cell may further include a carbon dioxide supply unit that supplies carbon dioxide to the anode chamber, a recirculation unit that supplies a discharge from the anode chamber to the cathode chamber, and a diaphragm located between the anode chamber and the cathode chamber.

[0010] In one embodiment, the fuel cell may further include a carbon dioxide supply unit that supplies carbon dioxide to the anode chamber, a first separation unit that separates the discharged material from the anode chamber into a first component and a second component, a first collection unit that collects the first component from the first separation unit, a recirculation unit that supplies the second component from the first separation unit to the cathode chamber, and a diaphragm located between the anode chamber and the cathode chamber. In one embodiment, at least one selected from the group consisting of hydrogen and carbon monoxide, formic acid, formaldehyde, methanol, methane, and ethylene may be produced in the anode chamber.

[0011] In one embodiment, the absolute value of the redox potential based on the standard electrode potential between the negative and positive electrode compartments may be 1.23 V or less. In one embodiment, the carbon dioxide supply unit can supply at least one selected from the group consisting of dry carbon dioxide, humidified carbon dioxide, and dissolved carbon dioxide.

[0012] In one embodiment, the fuel cell may further include at least one of a hydrogen supply unit that supplies hydrogen to the positive electrode chamber and an electrolyte supply unit that supplies an electrolyte to the positive electrode chamber. In one embodiment, the device may further include a second collection section for collecting exhaust from the positive electrode chamber.

[0013] In one embodiment, the first separation section may include at least one selected from the group consisting of a gas-liquid separator, a gas purifier, an adsorption tower, an absorption tower, and a gas-permeable membrane. In one embodiment, the first separation section outputs hydrogen and unreacted carbon dioxide as the second component, and the output of the cathode chamber can be recycled to the carbon dioxide supply section.

[0014] In one embodiment, the fuel cell further includes a second separation section that separates hydrogen and unreacted carbon dioxide, respectively, and the first separation section discharges hydrogen and unreacted carbon dioxide to the second separation section, the second separation section supplies the hydrogen to the recirculation section, the second separation section recirculates the unreacted carbon dioxide to the carbon dioxide supply section, and the recirculation section supplies the hydrogen from the second separation section to the positive electrode chamber.

[0015] In one embodiment, the system further includes a second separation section that separates hydrogen and other components from the discharged material of the negative electrode chamber, the second separation section supplies the hydrogen to the recirculation section, the recirculation section supplies the hydrogen from the second separation section to the positive electrode chamber, the second separation section discharges the other components to the first separation section, the first separation section separates the discharged material of the second separation section into a first component and a second component, and the first separation section can recirculate unreacted carbon dioxide to the carbon dioxide supply section. Effect of the Invention

[0016] According to one aspect of the present invention, purification steps can be omitted or minimized and by-product hydrogen can be removed. According to another aspect of the present invention, the voltage difference in the electrochemical reaction can be minimized to improve energy efficiency. According to yet another aspect of the present invention, the product produced through the carbon dioxide conversion system can be obtained with high purity.

[0017] It should be understood that the effects of the present invention are not limited to the effects described above, but include all effects that can be inferred from the configuration of the invention described in the detailed description of the present invention or the claims. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram illustrating an exemplary carbon dioxide conversion system according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating an exemplary carbon dioxide conversion system according to another embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram illustrating an example of a carbon dioxide conversion system according to yet another embodiment of the present invention. [Figure 4] FIG. 4 is a diagram illustrating an example of a carbon dioxide conversion system according to yet another embodiment of the present invention. [Diagram 5] FIG. 5 is a diagram illustrating an example of a carbon dioxide conversion system according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention will be described below. However, the present invention can be embodied in various different forms and is not limited to the embodiments described herein. In addition, in order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

[0020] Throughout the specification, when any part is said to be "connected" to another part, this includes not only the case where it is "directly connected" to another part, but also the case where it is "indirectly connected" through another member in between. Furthermore, when any part is said to "include" a certain component, this does not mean that it excludes the other component, but that it may further include the other component, unless otherwise specified to the contrary.

[0021] As used herein, the term "standard electrode potential" refers to a potential measured using a battery prepared by combining a standard hydrogen electrode with an electrode to be measured under conditions of 25° C., 1 atm, and 1M ion concentration. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0022] Carbon Dioxide Conversion System FIG. 1 is a diagram illustrating an example of a carbon dioxide conversion system 10 according to one embodiment of the present invention. Referring to FIG. 1, a carbon dioxide conversion system 10 according to one embodiment of the present invention may include an anode chamber 113 in which a carbon dioxide reduction reaction takes place, and a cathode chamber 123 in which a hydrogen oxidation reaction takes place.

[0023] The carbon dioxide conversion system 10 can convert carbon dioxide, which is a type of greenhouse gas, into useful compounds using little energy in an electrolytic cell 100 equipped with an anode chamber 113 including an anode 111 and a cathode chamber 123 including a cathode 121. Unlike conventional electrolysis devices that use a large amount of energy to perform an oxidation-reduction reaction between carbon dioxide and water and refine and remove by-product hydrogen, the carbon dioxide conversion system 10 can use an oxidation-reduction reaction between carbon dioxide and hydrogen.

[0024] In one embodiment of the carbon dioxide conversion system 10, the system may further include a carbon dioxide supply section 115 that supplies carbon dioxide to the anode chamber 113, a recirculation section 127 that supplies the exhaust gas from the anode chamber 113 to the cathode chamber 123, and a diaphragm 130 positioned between the anode chamber 113 and the cathode chamber 123.

[0025] In addition, in another embodiment of the carbon dioxide conversion system 10, the system may further include a carbon dioxide supply unit 115 that supplies carbon dioxide to the anode chamber 113, a first separation unit 117 that separates the discharged material from the anode chamber 113 into a first component and a second component, a first collection unit 119 that collects the first component from the first separation unit 117, a recirculation unit 127 that supplies the second component from the first separation unit 117 to the cathode chamber 123, and a diaphragm 130 located between the anode chamber 113 and the cathode chamber 123.

[0026] In one example of the carbon dioxide conversion system 10 described above, a material may flow from the carbon dioxide supply unit 115 to the anode chamber 113. The material in the anode chamber 113 may be discharged to the cathode chamber 123 via the recirculation unit 127 or may be discharged to the first separation unit 117. When the material discharged from the anode chamber 113 passes through the first separation unit 117, it is separated into a first component and a second component, and is discharged separately to the first collection unit 119 and the recirculation unit 127. Here, the material that passes through the recirculation unit 127 may be supplied to the cathode chamber 123. The material in the cathode chamber 123 may be completely reacted or discharged via the second collection unit 129 of a selective configuration.

[0027] The carbon dioxide conversion system 10 may include an electrolytic cell 100 in which the anode chamber 113 containing the anode 111 and the cathode chamber 123 containing the cathode 121 are partitioned by the diaphragm 130 .

[0028] A carbon dioxide reduction reaction may occur in the negative electrode 111 of the carbon dioxide conversion system 10. Examples of the negative electrode 111 include, but are not limited to, an electrode including at least one selected from the group consisting of Hg, Ti, In, Sn, Cd, Au, Ag, Zn, Pd, and Cu.

[0029] According to one example, the reactions occurring in the negative electrode chamber 113 including the negative electrode 111 can be expressed by the following reaction formulas (1) to (8). <Reaction formula> (1) CO2 + 2H + +2e - →CO+H2O (2)CO2+2H + +2e - →HCOOH (3) CO2 + 4H + +4e - →HCHO+H2O (4) CO2+6H + +6e - →CH3OH+H2O (5)CO2+8H + +8e - →CH4+2H2O (6) 2CO2+12H+ +12e - →C2H4+4H2O (7) 2H2O+2e - →H2+2OH - (8)2H + +2e - →H2

[0030] Reaction (1) is a reaction in which carbon dioxide (CO2) is converted to carbon monoxide (CO) and has a standard electrode potential of -0.53 V. Reaction (2) is a reaction in which carbon dioxide (CO2) is converted to formic acid (HCOOH) and has a standard electrode potential of -0.61 V. Reaction (3) is a reaction in which carbon dioxide (CO2) is converted to formaldehyde (HCHO) and has a standard electrode potential of -0.51 V. Reaction (4) is a reaction in which carbon dioxide (CO2) is converted to methanol (CH3OH) and has a standard electrode potential of -0.38 V. Reaction (5) is a reaction in which carbon dioxide (CO2) is converted to methane (CH4) and has a standard electrode potential of -0.24 V. Reaction (6) is a reaction in which carbon dioxide (CO2) is converted to ethylene (C2H4) and has a standard electrode potential of -0.34 V.

[0031] Reaction (7) is a reaction in which water (H2O) is converted to hydrogen (H2) and has a standard electrode potential of -0.83 V. Reaction (8) is a reaction in which hydrogen cations (H + ) to produce hydrogen (H2), and has a standard electrode potential of 0 V. This reaction can be induced in a desired manner by varying the type of the negative electrode 111 and the reaction conditions.

[0032] Carbon dioxide undergoes an electrochemical reduction reaction in the anode chamber 113 to produce at least one selected from the group consisting of hydrogen (H2), carbon monoxide (CO), formic acid (HCOOH), formaldehyde (HCHO), methanol (CH3OH), methane (CH4) and ethylene (C2H4), but is not limited to these.

[0033] A hydrogen oxidation reaction may occur at the positive electrode 121 of the carbon dioxide conversion system 10. Examples of the positive electrode 121 include, but are not limited to, an Fe electrode, a stainless steel (SUS) electrode, a Ni electrode, a Ti electrode, and a catalytic oxide electrode in which a platinum-based oxide such as Ru, Ir, Ta, or Pt is coated on a Ti substrate.

[0034] The reaction that occurs in the positive electrode chamber 123 including the positive electrode 121 can be expressed as the following reaction formula (9). <Reaction formula> (9) H2→2H + +2e -

[0035] Reaction (9) is the reverse reaction of reaction (8) and has a standard electrode potential of 0 V. Therefore, the absolute value of the redox potential based on the standard electrode potential between the negative electrode chamber 113 and the positive electrode chamber 123 can be 1.23 V or less, for example, 1.23 V or less, 1.20 V or less, 1.15 V or less, 1.10 V or less, 1.05 V or less, 1.00 V or less, 0.95 V or less, 0.90 V or less, 0.85 V or less, 0.80 V or less, 0.75 V or less, 0.70 V or less, or 0.65 V or less, but is not limited thereto. When the absolute value of the redox potential is small, carbon dioxide can be converted with a smaller amount of electrical energy.

[0036] The anode 111 and the cathode 121 can perform an oxidation-reduction reaction by receiving electrical energy from an external power source. Therefore, the less energy required for the electrochemical carbon dioxide conversion reaction of the anode 111 and the cathode 121, the better the efficiency. Such energy can be expressed as the difference in standard electrode potential between the anode 111 as a reduction electrode and the cathode 121 as an oxidation electrode.

[0037] The positive electrode chamber 123 may further include a predetermined catalyst to facilitate the reaction according to reaction formula (9). The catalyst may include / contain at least one platinum-based element selected from the group consisting of Pt, Pd, Ru, Ir, and Rh, or may include a transition metal element such as Ni, Cu, Fe, or a mixture thereof, but is not limited thereto.

[0038] Conventional carbon capture and utilization technologies use a water splitting reaction in the positive electrode chamber, as shown in reaction formula (P) below. <Reaction formula> (P)H2O→1 / 2O2+2H + +2e -

[0039] The standard electrode potential of reaction formula (P) is 1.23V, and a voltage of 1.47V to 2.06V must be applied when connecting to the negative electrode chamber to convert carbon dioxide.

[0040] Meanwhile, since the carbon dioxide conversion system 10 uses the hydrogen oxidation reaction at the positive electrode 121, the carbon dioxide conversion reaction is possible even when a relatively low voltage of 1.23 V or less is applied, and thus the carbon dioxide conversion reaction can be performed, resulting in excellent energy efficiency. In addition, hydrogen, which would have to be removed through a purification process in conventional systems, is directly used in the carbon dioxide conversion reaction, so purification facilities can be minimized.

[0041] The anode chamber 113 and the cathode chamber 123 may each contain an electrolyte. The electrolyte can provide electrical conductivity to the anode chamber 113 or the cathode chamber 123 and transmit electrical energy so that the electrochemical oxidation-reduction reaction described above can occur. In general, the electrochemical reduction reaction can occur in an aqueous solution. Thus, the electrolyte can be an ionic compound dissociated in water. The electrolytes in the anode chamber 113 and the cathode chamber 123 can be the same or different depending on the purpose.

[0042] The carbon dioxide supply unit 115 may supply carbon dioxide to the anode chamber 113 so that the reduction reaction of carbon dioxide described above occurs. The carbon dioxide supply unit 115 may supply carbon dioxide to the electrolyte in the anode chamber 113, or may supply carbon dioxide in a dissolved state in the electrolyte. For example, the carbon dioxide supply unit 115 may supply at least one selected from the group consisting of dry carbon dioxide, humidified carbon dioxide, and dissolved carbon dioxide to the anode chamber 113, but is not limited thereto.

[0043] In this case, carbon dioxide may be supplied to the electrolyte at high pressure so that the carbon dioxide can be more easily dissolved in the electrolyte, or carbon dioxide may be supplied in the form of fine bubbles, or carbon dioxide may be supplied in a membrane contact manner, but is not limited to these methods.

[0044] The anode chamber 113 may further contain at least one selected from the group consisting of hydrogen (H2), carbon monoxide (CO), formic acid (HCOOH), formaldehyde (HCHO), methanol (CH3OH), methane (CH4), and ethylene (C2H4) produced by the above-mentioned reaction in addition to the supplied carbon dioxide (CO2). The anode chamber 113 may discharge a material containing the compound to the cathode chamber 123 or a first separation section 117. The first separation section 117 may separate the material discharged from the anode chamber 113 into the first component and the second component.

[0045] Therefore, the second component passing through the first separation unit 117 may include hydrogen generated in the anode chamber 113. The hydrogen may be supplied to the cathode chamber 123 via the recirculation unit 127. The hydrogen supplied to the cathode chamber 123 may be converted into hydrogen cations and electrons through the above-mentioned oxidation reaction.

[0046] In one example, when the first component that has passed through the first separation unit 117 contains an electrolyte, the electrolyte may be recycled to the anode chamber 113. In one example, the electrolyte may be recycled through the carbon dioxide supply unit 115 in a state in which carbon dioxide is dissolved therein.

[0047] The diaphragm 130 can separate the anode chamber 113 and the cathode chamber 123. The diaphragm 130 can selectively move a target substance while separating the anode chamber 113 and the cathode chamber 123 in the electrolytic cell 100.

[0048] The diaphragm 130 may be an ion exchange membrane, for example, a cation exchange membrane or an anion exchange membrane. When the diaphragm 130 is a cation exchange membrane, the surface facing the negative electrode chamber 113 may have a shielding property against anions or a cation exchange functional group, but is not limited thereto.

[0049] In order for the hydrogen oxidation reaction to occur in the cathode 121, hydrogen must be continuously supplied to the cathode chamber 123. When carbon dioxide is reduced only with the by-product hydrogen generated in the anode chamber 113 due to a competitive reaction, the hydrogen required for the reaction may be insufficient. In this case, the carbon dioxide conversion system 10 may further include a hydrogen supply unit 125 for supplying hydrogen to the cathode chamber 123. FIG. 2 is a diagram showing an example of such a carbon dioxide conversion system 10.

[0050] 2, in addition to the recirculation unit 127 that supplies recycled by-product hydrogen to the positive electrode chamber 123, the hydrogen supply unit 125 that supplies separate hydrogen may be provided. The hydrogen supply unit 125 may directly supply hydrogen to the positive electrode chamber 123 or may supply hydrogen in a form dissolved in an electrolyte. In addition to the hydrogen supply unit 125, an electrolyte supply unit (not shown) that supplies a separate electrolyte, for example, potassium carbonate (K2CO3), to the positive electrode chamber 123 may be further provided.

[0051] The carbon dioxide conversion system 10 may further include a second collection unit 129 that collects the exhaust from the cathode chamber 123. The type of exhaust collected by the second collection unit 129 may vary depending on the components supplied to the cathode chamber 123 through the recirculation unit 127.

[0052] The first separation section 117 may include at least one selected from the group consisting of a gas-liquid separator, a gas purifier, an adsorption tower, an absorption tower, and a gas permeable membrane depending on the purpose, but is not limited thereto.

[0053] The first separation unit 117 may separate the liquid phase and the gas phase of the material discharged from the anode chamber 113 into the first component and the second component, respectively. The separated second component is supplied to the cathode chamber 123 to remove hydrogen, and a high-purity gas product from which hydrogen has been removed may be obtained in the second collection unit 129.

[0054] In another embodiment, the first separation unit 117 separates the target product from the material discharged from the anode chamber 113 into the first component and supplies it to the first collection unit 119, and separates hydrogen and unreacted carbon dioxide into the second component for recycling. Figure 3 is a diagram showing an example of such a carbon dioxide conversion system 10.

[0055] Referring to FIG. 3, the first component passing through the first separation section 117 may include at least one selected from the group consisting of carbon monoxide (CO), formic acid (HCOOH), formaldehyde (HCHO), methanol (CHOH), methane (CH) and ethylene (CH), but is not limited thereto.

[0056] In addition, the hydrogen and unreacted carbon dioxide separated into the second component in the first separation unit 117 may pass through the recirculation unit 127 and be supplied to the positive electrode chamber 123. After hydrogen is removed through an oxidation reaction in the positive electrode chamber 123, the unreacted carbon dioxide may be recycled to the carbon dioxide supply unit 115. Since the supplied second component consists of hydrogen and unreacted carbon dioxide, the purity of the unreacted carbon dioxide recycled to the carbon dioxide supply unit 115 is high.

[0057] Although omitted in FIG. 3, the carbon dioxide conversion system 10 having such a configuration may further include the hydrogen supply unit 125 for supplying hydrogen to the positive electrode chamber 123, as described above. The carbon dioxide conversion system 10 may further include a second separation section 118. Figures 4 and 5 are diagrams showing an example of such a carbon dioxide conversion system 10.

[0058] 4, the carbon dioxide conversion system 10 may further include a second separation unit 118 that separates hydrogen and unreacted carbon dioxide. In this case, the first separation unit 117 may discharge hydrogen and unreacted carbon dioxide to the second separation unit 118 instead of the recirculation unit 127. The second separation unit 118 may supply separated hydrogen to the recirculation unit 127 and recirculate separated unreacted carbon dioxide to the carbon dioxide supply unit 115. The recirculation unit 127 may supply hydrogen to the positive electrode chamber 123 from the second separation unit 118 instead of the first separation unit 117.

[0059] Referring to FIG. 5, the carbon dioxide conversion system 10 may further include a second separation unit 118 that separates hydrogen and other components. In this case, the second separation unit 118 may supply the separated hydrogen to a recirculation unit 127. The recirculation unit 127 may supply hydrogen to the positive electrode chamber 123 from the second separation unit 118 instead of the first separation unit 117. In addition, the second separation unit 118 may discharge other components to the first separation unit 117. The first separation unit 117 may separate the other components discharged from the second separation unit 118 into a first component including a target product and a second component including unreacted carbon dioxide. The first separation unit 117 may supply the first component to a first collection unit 119 and recirculate the second component to the carbon dioxide supply unit 115.

[0060] Although omitted in FIG. 4 and FIG. 5, the carbon dioxide conversion system 10 having such a configuration may further include the hydrogen supply unit 125 for supplying hydrogen to the positive electrode chamber 123, as described above.

[0061] When such a carbon dioxide conversion system 10 is used, carbon dioxide or carbon monoxide is not supplied to the positive electrode chamber 123, so that a catalyst that is easily poisoned by carbon monoxide or carbon dioxide can be used as the catalyst for the positive electrode 121. For example, a platinum-based compound that is easily poisoned by carbon monoxide or carbon dioxide can be used as the electrode catalyst for the positive electrode 121.

[0062] In the carbon dioxide conversion system 10 having this configuration, since products other than hydrogen and unreacted carbon dioxide are not supplied to the positive electrode chamber 123, the second collector 129 may be omitted.

[0063] The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that the present invention can be easily modified in other specific forms without changing the technical idea or essential features of the present invention. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed form, and similarly, each component described as a distributed type may be implemented in a combined form.

[0064] The scope of the present invention is defined by the claims set forth below, and all modifications and variations that fall within the meaning and scope of the claims and their equivalent concepts should be understood to be included within the scope of the present invention. [Explanation of symbols]

[0065] 10 Carbon Dioxide Conversion System 100 electrolytic cell 111 Negative electrode 113 Anode chamber 115 Carbon Dioxide Supply Unit 117 1st separation section 118 Second separation section 119 First Collection Department 121 Positive electrode 123 Positive electrode chamber 125 Hydrogen Supply Unit 127 Recirculation section 129 2nd Collection Department 130 Diaphragm

Claims

1. an anode chamber in which a carbon dioxide reduction reaction takes place; The positive electrode chamber where the hydrogen oxidation reaction takes place A carbon dioxide conversion system comprising:

2. a carbon dioxide supply unit for supplying carbon dioxide to the negative electrode chamber; A recirculation section that supplies the discharged product from the negative electrode chamber to the positive electrode chamber; A diaphragm located between the negative electrode chamber and the positive electrode chamber; 10. The carbon dioxide conversion system of claim 1, further comprising:

3. a carbon dioxide supply unit for supplying carbon dioxide to the negative electrode chamber; a first separation section that separates the discharged material from the anode chamber into a first component and a second component; a first collection section that collects the first component from the first separation section; a recirculation section for supplying the second component from the first separation section to the positive electrode chamber; A diaphragm located between the negative electrode chamber and the positive electrode chamber; 10. The carbon dioxide conversion system of claim 1, further comprising:

4. 4. The carbon dioxide conversion system according to claim 1, wherein at least one selected from the group consisting of hydrogen and carbon monoxide, formic acid, formaldehyde, methanol, methane and ethylene is produced in the anode chamber.

5. 4. The carbon dioxide conversion system according to claim 1, wherein the absolute value of the oxidation-reduction potential between the negative electrode chamber and the positive electrode chamber based on the standard electrode potential is 1.23 V or less.

6. The carbon dioxide conversion system according to claim 1 , wherein the carbon dioxide supply unit supplies at least one selected from the group consisting of dry carbon dioxide, humidified carbon dioxide, and dissolved carbon dioxide.

7. The carbon dioxide conversion system according to claim 1 , further comprising at least one of a hydrogen supply unit that supplies hydrogen to the positive electrode chamber and an electrolyte supply unit that supplies an electrolyte to the positive electrode chamber.

8. The carbon dioxide conversion system according to claim 1 , further comprising a second collection section for collecting the exhaust from the positive electrode chamber.

9. The carbon dioxide conversion system according to claim 3 , wherein the first separation section includes at least one selected from the group consisting of a gas-liquid separator, a gas purifier, an adsorption tower, an absorption tower, and a gas permeable membrane.

10. The first separation section discharges hydrogen and unreacted carbon dioxide as the second component, 4. The carbon dioxide conversion system of claim 3, wherein the cathode chamber effluent is recycled to the carbon dioxide supply.

11. Further comprising a second separation section for separating hydrogen and unreacted carbon dioxide, The first separation section discharges hydrogen and unreacted carbon dioxide to the second separation section, The second separation section supplies the hydrogen to the recirculation section, The second separation section recirculates the unreacted carbon dioxide to the carbon dioxide supply section, The carbon dioxide conversion system according to claim 3 , wherein the recirculation section supplies the hydrogen from the second separation section to the positive electrode chamber.

12. Further comprising a second separation section for separating the discharged gas from the negative electrode chamber into hydrogen and other components, The second separation section supplies the hydrogen to the recirculation section, The recirculation section supplies the hydrogen from the second separation section to the positive electrode chamber, The second separation section discharges the other components to the first separation section, The first separation section separates the discharged material of the second separation section into a first component and a second component, The carbon dioxide conversion system according to claim 3 , wherein the first separation section recycles unreacted carbon dioxide to the carbon dioxide supply section.

Images