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 high-purity products. [Background technology]

[0002] Recently, the impacts of global climate change have become significant. As a result, countries around the world are making efforts to reduce various substances that cause global warming. Carbon dioxide, in particular, has attracted the most attention due to the rapid increase in emissions accompanying 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). Research is actively 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, a target of the United Nations Framework Convention on Climate Change.

[0004] Methods for utilizing carbon dioxide can be broadly divided into non-conversion methods, which use carbon dioxide itself for beneficial purposes, and conversion methods, which convert carbon dioxide into useful compounds for recycling. Of these, carbon dioxide conversion technologies can be classified into chemical conversion technologies and biological conversion technologies. Among these, chemical conversion technologies further include thermal catalytic chemical conversion, electrochemical conversion, and photochemical conversion, depending on their technical characteristics.

[0005] Electrochemical conversion technology involves supplying carbon dioxide to an aqueous solution in an electrolysis apparatus and converting it into organic compounds by reducing it with electrical energy. Depending on the type of electrode material and reaction conditions, organic compounds such as formic acid, methane, ethane, carbon monoxide, oxalic acid, and synthesis gas can be selectively produced. Such electrochemical conversion technology can be carried out under normal temperature and pressure conditions. Furthermore, the raw materials required for the reaction are simply an electrolyte and carbon dioxide, and if the electrolyte is recycled, conversion is possible without the emission of chemical substances. In addition, the system is simple and modular, and research and development are progressing in various ways.

[0006] In electrolysis devices, hydrogen gas is generated as a by-reaction and mixes with unreacted carbon dioxide. Therefore, in order to recover and recycle the unreacted carbon dioxide, it is necessary to separate the hydrogen.

[0007] Conventionally, gas-liquid separators, membranes, and compressors have been used to separate the by-product hydrogen from unreacted carbon dioxide. However, these devices increase costs and impose significant spatial constraints. Furthermore, separating hydrogen and carbon dioxide using membranes is inefficient, resulting in insufficient effective recovery and recirculation of carbon dioxide. [Overview of the project] [Problems that the invention aims to solve]

[0008] The present invention aims to solve the problems of the prior art described above, and the object of the present invention is to provide a carbon dioxide conversion system that is energy efficient and capable of producing high-purity products by oxidizing by-product hydrogen in the process of converting carbon dioxide via an electrochemical reduction reaction. [Means for solving the problem]

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

[0010] In one embodiment, the system may further include a carbon dioxide supply unit that supplies carbon dioxide to the negative electrode chamber, a first separation unit that separates the waste from the negative electrode 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 positive electrode chamber, and a diaphragm located between the negative electrode chamber and the positive electrode chamber. In one embodiment, hydrogen and at least one selected from the group consisting of carbon monoxide, formic acid, formaldehyde, methanol, methane, and ethylene may be generated in the negative electrode chamber.

[0011] In one embodiment, the absolute value of the oxidation-reduction potential, with respect to the standard electrode potential between the negative electrode chamber and the positive electrode chamber, 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 system 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, a second collection unit for collecting waste from the positive electrode chamber may be further included.

[0013] In one embodiment, the first separation unit 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 unit discharges hydrogen and unreacted carbon dioxide as the second component, and the discharge from the positive electrode chamber can be recycled to the carbon dioxide supply unit.

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

[0015] In one embodiment, it further includes a second separation unit that separates the exhaust of the negative electrode chamber into hydrogen and other components respectively. The second separation unit supplies the hydrogen to the recirculation unit. The recirculation unit supplies the hydrogen from the second separation unit to the positive electrode chamber. The second separation unit discharges the other components to the first separation unit. The first separation unit separates the exhaust of the second separation unit into a first component and a second component. The first separation unit can recirculate unreacted carbon dioxide to the carbon dioxide supply unit.

Advantages of the Invention

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

[0017] The advantages of the present invention are not limited to the above-mentioned advantages, and it should be understood to include all advantages that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

Brief Description of the Drawings

[0018] [Figure 1] FIG. 1 is a diagram showing an example of a carbon dioxide conversion system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of a carbon dioxide conversion system according to another embodiment of the present invention. [Figure 3] Figure 3 shows an example of a carbon dioxide conversion system according to yet another embodiment of the present invention. [Figure 4] Figure 4 shows an example of a carbon dioxide conversion system according to yet another embodiment of the present invention. [Figure 5] Figure 5 shows an example of a carbon dioxide conversion system according to yet another embodiment of the present invention. [Modes for carrying out the invention]

[0019] The present invention will be described below. However, the present invention can be embodied in various different forms and is therefore not limited to the embodiments described herein. Furthermore, in order to clearly illustrate the present invention in the drawings, parts unrelated to the description have been omitted, and similar parts have been given similar reference numerals throughout the specification.

[0020] Throughout the specification, when any part is said to be “connected” to other parts, this includes not only cases where they are “directly connected,” but also cases where they are “indirectly connected” through the interposition of other components. Furthermore, when any part is said to “include” a certain component, this does not mean that it excludes other components, but rather that it may further include other components, unless otherwise stated.

[0021] In this specification, "standard potential" refers to the potential measured in a battery manufactured by combining a standard hydrogen electrode with the electrode to be measured under the conditions of 25°C, 1 atm, and an ion concentration of 1M. Embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0022] Carbon dioxide conversion system Figure 1 is a diagram showing an example of a carbon dioxide conversion system 10 according to one aspect of the present invention. Referring to Figure 1, a carbon dioxide conversion system 10 according to one aspect of the present invention may include a negative electrode chamber 113 in which a reduction reaction of carbon dioxide takes place, and a positive electrode chamber 123 in which an oxidation reaction of hydrogen takes place.

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

[0024] In one 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 negative electrode chamber 113, a recirculation unit 127 that supplies the waste from the negative electrode chamber 113 to the positive electrode chamber 123, and a diaphragm 130 located between the negative electrode chamber 113 and the positive electrode chamber 123.

[0025] In another embodiment of the carbon dioxide conversion system 10, it may further include a carbon dioxide supply unit 115 that supplies carbon dioxide to the negative electrode chamber 113, a first separation unit 117 that separates the waste from the negative electrode 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 positive electrode chamber 123, and a diaphragm 130 located between the negative electrode chamber 113 and the positive electrode chamber 123.

[0026] In one example of the aforementioned carbon dioxide conversion system 10, substances can flow from the carbon dioxide supply unit 115 into the negative electrode chamber 113. The substances inside the negative electrode chamber 113 can be discharged into the positive electrode chamber 123 via the recirculation unit 127 or discharged into the first separation unit 117. When the substances discharged from the negative electrode chamber 113 pass through the first separation unit 117, they are separated into a first component and a second component and discharged separately to the first collection unit 119 and the recirculation unit 127. Here, the substances that have passed through the recirculation unit 127 can be supplied to the positive electrode chamber 123. The substances inside the positive electrode chamber 123 can all react or be discharged via the second collection unit 129 with a selective configuration.

[0027] The carbon dioxide conversion system 10 may include an electrolytic cell 100 in which the negative electrode chamber 113 including the negative electrode 111 and the positive electrode chamber 123 including the positive electrode 121 are partitioned by the separator 130.

[0028] A reduction reaction of carbon dioxide can be carried out at the negative electrode 111 of the carbon dioxide conversion system 10. Examples of the negative electrode 111 include, but are not limited to, electrodes containing 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 reaction occurring in the negative electrode chamber 113 including the negative electrode 111 can be expressed as in the following reaction formulas (1) to (8). <Reaction formula> (1) CO2 + 2H+ 2e - → CO + H2O (2) CO2 + 2H + + 2e - [[ID=​​​​​​​​​​​​​​​​​​​​​+ +12e - →C2H4+4H2O (7) 2H2O + 2e - →H2+2OH - (8) 2H + +2e - →H2

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

[0031] Furthermore, reaction equation (7) is a reaction in which water (H2O) is converted to hydrogen (H2), and has a standard electrode potential of -0.83V, and reaction equation (8) is a reaction in which hydrogen cation (H2) is converted. + This is a reaction in which hydrogen (H2) is produced from ) and has a standard electrode potential of 0V. Such reactions can be induced in the desired form by varying the type of negative electrode 111 and the reaction conditions.

[0032] In the negative electrode chamber 113, carbon dioxide undergoes an electrochemical reduction reaction, which may produce hydrogen (H2) and at least one selected from the group consisting of 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 can be carried out 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 platinum-based oxides such as Ru, Ir, Ta, and Pt are coated on a Ti substrate.

[0034] The reaction that takes place in the positive electrode chamber 123, which includes the positive electrode 121, can be expressed as shown in the following reaction equation (9). <Reaction Equation> (9) H2 → 2H + +2e -

[0035] Reaction equation (9) is the reverse reaction of reaction equation (8) and has a standard electrode potential of 0V. Therefore, the absolute value of the oxidation-reduction potential with respect to the standard electrode potential between the negative electrode chamber 113 and the positive electrode chamber 123 may be 1.23V or less, for example, 1.23V or less, 1.20V or less, 1.15V or less, 1.10V or less, 1.05V or less, 1.00V or less, 0.95V or less, 0.90V or less, 0.85V or less, 0.80V or less, 0.75V or less, 0.70V or less, or 0.65V or less, but is not limited to these. A smaller absolute value of the oxidation-reduction potential allows carbon dioxide to be converted with less electrical energy.

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

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

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

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

[0040] On the other hand, since the carbon dioxide conversion system 10 uses the oxidation reaction of hydrogen at the positive electrode 121, the carbon dioxide conversion reaction can be carried out even when a relatively low voltage of 1.23V or less is applied, and it can have excellent energy efficiency. Furthermore, since the hydrogen that would normally be removed through the purification process in conventional systems is used directly in the carbon dioxide conversion reaction, the amount of purification equipment can be minimized.

[0041] The negative electrode chamber 113 and the positive electrode chamber 123 may each contain an electrolyte. The electrolyte imparts conductivity to the negative electrode chamber 113 or the positive electrode chamber 123 and can transfer electrical energy to carry out the electrochemical oxidation-reduction reaction described above. Generally, the electrochemical reduction reaction can be carried out in an aqueous solution. Therefore, the electrolyte may be an ionic compound dissociated in water. The electrolytes in the negative electrode chamber 113 and the positive electrode chamber 123 may be the same or different depending on the purpose.

[0042] The carbon dioxide supply unit 115 can supply carbon dioxide to the anode chamber 113 so that the carbon dioxide reduction reaction described above can take place. The carbon dioxide supply unit 115 can supply carbon dioxide to the electrolyte in the anode chamber 113, or it can supply carbon dioxide dissolved in the electrolyte. For example, the carbon dioxide supply unit 115 can 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 to these.

[0043] In this case, carbon dioxide can be supplied to the electrolyte under high pressure so that it can dissolve more easily in the electrolyte, or it can be supplied as microbubbles, or carbon dioxide can be supplied by a membrane contact method, but the method is not limited to these methods.

[0044] In addition to the supplied carbon dioxide (CO2), the negative electrode 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 reaction described above. The negative electrode chamber 113 can discharge the substance containing the compound to the positive electrode chamber 123 or the first separation unit 117. The first separation unit 117 can separate the substance discharged from the negative electrode chamber 113 into the first component and the second component.

[0045] Therefore, the second component that has passed through the first separation unit 117 may include hydrogen produced in the negative electrode chamber 113. The hydrogen can be supplied to the positive electrode chamber 123 via the recirculation unit 127. The hydrogen supplied to the positive electrode chamber 123 can be converted into hydrogen cations and electrons via the oxidation reaction described above.

[0046] In one example, if the first component that has passed through the first separation unit 117 contains an electrolyte, the electrolyte can be recycled to the negative electrode chamber 113. In another example, the electrolyte can be recycled via the carbon dioxide supply unit 115 in a state in which carbon dioxide has been dissolved.

[0047] The diaphragm 130 can partition the negative electrode chamber 113 and the positive electrode chamber 123. The diaphragm 130 can selectively move the target substance while separating the negative electrode chamber 113 and the positive electrode 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. If the diaphragm 130 is a cation exchange membrane, the surface facing the negative electrode chamber 113 may have anion-shielding properties or have cation-exchange functional groups, but is not limited to these.

[0049] For the hydrogen oxidation reaction described above to occur at the positive electrode 121, it is necessary to continuously supply hydrogen to the positive electrode chamber 123. If carbon dioxide is reduced using only the by-product hydrogen generated in the negative electrode chamber 113 by a competitive reaction, there may be a shortage of hydrogen necessary for the reaction. In such a case, the carbon dioxide conversion system 10 may further include a hydrogen supply unit 125 that supplies hydrogen to the positive electrode chamber 123. Figure 2 shows an example of such a carbon dioxide conversion system 10.

[0050] Referring to Figure 2, in addition to the recirculation unit 127 that supplies the recirculated by-product hydrogen to the positive electrode chamber 123, there may also be a hydrogen supply unit 125 that supplies hydrogen separately. In such a hydrogen supply unit 125, hydrogen can be supplied directly to the positive electrode chamber 123 or in the form of dissolved hydrogen in an electrolyte. Furthermore, in addition to the hydrogen supply unit 125, there may also be an electrolyte supply unit (not shown) that supplies another electrolyte, such as potassium carbonate (K2CO3), to the positive electrode chamber 123.

[0051] Furthermore, the carbon dioxide conversion system 10 may further include a second collection unit 129 for collecting emissions from the positive electrode chamber 123. The type of emissions collected by the second collection unit 129 may vary depending on the components supplied to the positive electrode chamber 123 via the recirculation unit 127.

[0052] The first separation unit 117 may include, but is not limited to, 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.

[0053] The first separation unit 117 can separate the liquid phase of the substance discharged from the negative electrode chamber 113 into the first component and the gaseous phase into the second component. By supplying the separated second component to the positive electrode chamber 123 and removing hydrogen, a high-purity gaseous product from which hydrogen has been removed can be obtained in the second collection unit 129.

[0054] In another embodiment, the first separation unit 117 can separate the target product from the material discharged from the negative electrode chamber 113 into a first component and supply it to the first collection unit 119, and separate hydrogen and unreacted carbon dioxide into a second component for recycling. Figure 3 shows an example of such a carbon dioxide conversion system 10.

[0055] Referring to Figure 3, the first component that has passed through the first separation unit 117 may include, but is not limited to, at least one selected from the group consisting of carbon monoxide (CO), formic acid (HCOOH), formaldehyde (HCHO), methanol (CH3OH), methane (CH4), and ethylene (C2H4).

[0056] Furthermore, the hydrogen and unreacted carbon dioxide separated into the second component in the first separation unit 117 can pass through the recirculation unit 127 and be supplied to the positive electrode chamber 123. After the hydrogen is removed in the positive electrode chamber 123 via an oxidation reaction, the unreacted carbon dioxide can be recirculated 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 recirculated to the carbon dioxide supply unit 115 is high.

[0057] Although not shown in Figure 3, this type of carbon dioxide conversion system 10 may also further include the hydrogen supply unit 125 that supplies hydrogen to the positive electrode chamber 123, as described above. The carbon dioxide conversion system 10 may further include a second separation unit 118. Figures 4 and 5 show an example of such a carbon dioxide conversion system 10.

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

[0059] Referring to Figure 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 can supply the separated hydrogen to a recirculation unit 127. The recirculation unit 127 can supply hydrogen to the positive electrode chamber 123 from the second separation unit 118, rather than from the first separation unit 117. The second separation unit 118 can also discharge the other components to the first separation unit 117. The first separation unit 117 can separate the other components discharged from the second separation unit 118 into a first component containing the desired product and a second component containing unreacted carbon dioxide. The first separation unit 117 can supply the first component to a first collection unit 119 and recirculate the second component to a carbon dioxide supply unit 115.

[0060] Although not shown in Figures 4 and 5, this type of carbon dioxide conversion system 10 may also further include the hydrogen supply unit 125 that supplies hydrogen to the positive electrode chamber 123, as described above.

[0061] When using such a carbon dioxide conversion system 10, carbon dioxide and carbon monoxide are not supplied to the positive electrode chamber 123, so a catalyst that is easily poisoned by carbon monoxide and 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 and carbon dioxide can be used as the electrode catalyst for the positive electrode 121.

[0062] In the carbon dioxide conversion system 10 of this configuration, since no products other than hydrogen or unreacted carbon dioxide are supplied to the positive electrode chamber 123, the second collection unit 129 can be omitted.

[0063] The foregoing description of the present invention is illustrative, and a person with ordinary skill in the art to which the invention pertains will understand that it can be easily modified in other specific forms without altering the technical idea or essential features of the invention. Therefore, the embodiments described above should be understood to be illustrative and not limiting in all respects. For example, each component described as a single type can be implemented in a distributed manner, and similarly, components described as distributed can be implemented in a combined manner.

[0064] The scope of the present invention is defined by the claims set forth below, and it should be understood that all modifications or altered forms derived from the meaning and scope of the claims and the concept of equivalents thereof are included within the scope of the present invention. [Explanation of Symbols]

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

Claims

1. The negative electrode chamber where the carbon dioxide reduction reaction takes place, The positive electrode chamber where the hydrogen oxidation reaction takes place and Includes, A carbon dioxide supply unit that supplies carbon dioxide to the negative electrode chamber, A first separation unit separates the waste from the negative electrode 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 positive electrode chamber, A diaphragm located between the negative electrode chamber and the positive electrode chamber. It further includes, The second component is a carbon dioxide conversion system containing hydrogen produced in the negative electrode chamber.

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

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

4. 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.

5. 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.

6. The carbon dioxide conversion system according to claim 1, further comprising a second collection unit for collecting waste from the positive electrode chamber.

7. The carbon dioxide conversion system according to claim 1, wherein the first separation unit 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.

8. The second component further comprises unreacted carbon dioxide, The carbon dioxide conversion system according to claim 1, wherein the waste from the positive electrode chamber is recycled to the carbon dioxide supply unit.

9. It further includes a second separation section for separating hydrogen and unreacted carbon dioxide, The first separation unit discharges hydrogen and unreacted carbon dioxide to the second separation unit. The second separation unit supplies the hydrogen to the recirculation unit, The second separation unit recirculates the unreacted carbon dioxide to the carbon dioxide supply unit. The carbon dioxide conversion system according to claim 1, wherein the recirculation unit supplies hydrogen from the second separation unit to the positive electrode chamber.

10. The system further includes a second separation unit that separates the waste from the negative electrode chamber into hydrogen and other components, respectively. The second separation unit supplies the hydrogen to the recirculation unit, The recirculation unit supplies the hydrogen from the second separation unit to the positive electrode chamber. The second separation unit discharges the other components to the first separation unit. The first separation unit separates the waste from the second separation unit into a first component and a second component. The carbon dioxide conversion system according to claim 1, wherein the first separation unit recirculates unreacted carbon dioxide to the carbon dioxide supply unit.

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