Electrolysis apparatus and operating method of thereof

Abstract

The present invention relates to an electrolysis device comprising an electrolysis stack, a first discharge pipe through which oxygen gas and liquid water are discharged to the outside of the electrolysis stack, a gas-liquid separation pipe connected to the electrolysis stack through the first discharge pipe, a vacuum gas discharger connected to the gas-liquid separation pipe through a second discharge pipe, and a vacuum control valve disposed in the second discharge pipe.

Description

Technology Field

[0001] The present invention relates to an electrolysis device for electrolyzing carbon dioxide and a method of operating the same. Background Technology

[0003] Carbon dioxide is a greenhouse gas that causes global warming and is a target that must be reduced. Methods for reducing carbon dioxide include carbon capture, chemical conversion, and electrochemical conversion. Among these, the electrochemical conversion method allows for precise control of components to produce other synthetic gases, thereby providing economic benefits compared to simply removing carbon dioxide. Additionally, carbon dioxide can be electrolyzed with water to obtain carbon monoxide, ethylene, methane, formic acid, formate, various hydrocarbons, and organic substances such as aldehydes or alcohols.

[0004] The process of electrochemical decomposition of carbon dioxide is similar to the electrolysis of water; however, since the activity of the electrochemical reaction improves in a strong basic atmosphere, an aqueous KOH solution of a certain concentration is generally used as the electrolyte. When current is applied while supplying water to the anode, the water decomposes into hydrogen ions and electrons, along with the generation of oxygen gas. The electrons move to the cathode through an external wire, and the hydrogen ions move to the cathode through an ion-selective membrane. At this time, the transferred electrons react with the carbon dioxide and water supplied to the cathode to form carbon monoxide and hydroxide ions (OH). - It decomposes into ), and the generated hydroxide ions are converted into the anode's hydrogen ions (H +It becomes electrically neutral by reacting with ) to produce water. Through the above process, the electrochemical decomposition reaction of carbon dioxide is completed. At this time, the water supplied along with the carbon dioxide reacts with the electrons that have moved separately from the carbon monoxide generation reaction to undergo electrolysis, generating hydrogen gas and simultaneously producing hydroxide ions. This reaction between water and electrons can be described as a competitive reaction with the carbon monoxide generation reaction. Since these reactions are electrochemical reactions, the amount of carbon monoxide produced and the hydrogen / carbon dioxide ratio can be easily controlled by adjusting the voltage.

[0005] Meanwhile, during the carbon dioxide electrolysis process, oxygen gas generated by the Oxygen Evolution Reaction (OER) at the anode forms bubbles between the electrode catalyst and the separator, which can inhibit the electrolysis reaction and reduce the efficiency of the electrolysis device. Therefore, the oxygen gas needs to be rapidly discharged or removed. Conventionally, to remove oxygen gas generated during the electrolysis process, experimental conditions or materials have been modified within the cell and / or stack, such as increasing the flow rate of the electrolyte introduced into the anode, altering the flow path structure of the cell and / or stack, changing the stack design to allow for pressurization, or improving the electrode or separator surfaces. However, there were limitations in improving the discharge and removal efficiency of the generated oxygen gas solely by changing the internal conditions of the cell and / or stack. Accordingly, if oxygen gas can be discharged more rapidly by adding external physical factors in addition to methods of changing the internal conditions of the cell and / or stack, the electrolysis efficiency of the cell and / or stack can be further improved. Prior art literature

[0006] (Patent Document 0001) JP 2017-002344 A The problem to be solved

[0007] The problem to be solved by the present invention is to provide an electrolysis device that effectively removes or rapidly discharges oxygen gas by an oxygen evolution reaction of a cell and / or stack, and a method of operating the same. means of solving the problem

[0009] The present invention provides an electrolysis device and a method of operating the same.

[0010] (1) The present invention provides an electrolysis device comprising an electrolysis stack, a first discharge pipe through which gas and liquid are discharged to the outside of the electrolysis stack, a gas-liquid separation pipe connected to the electrolysis stack through the first discharge pipe, a vacuum gas discharger connected to the gas-liquid separation pipe through a second discharge pipe, and a vacuum control valve disposed in the second discharge pipe.

[0011] (2) The present invention provides an electrolysis apparatus in which the gas-liquid separation tube in (1) separates the gas and liquid discharged from the electrolysis stack.

[0012] (3) The present invention provides an electrolysis apparatus in which, in (1) or (2), the gas separated from the gas-liquid separation tube is discharged to the outside by the vacuum gas discharger, and the liquid separated from the gas-liquid separation tube is introduced into the electrolysis stack.

[0013] (4) The present invention provides an electrolysis device in which, in any one of (1) to (3), the vacuum control valve is repeatedly opened and closed.

[0014] (5) The present invention provides an electrolysis device in which, in any one of (1) to (4), the electrolysis device further comprises a gas-liquid separator between the gas-liquid separation tube and the electrolysis stack.

[0015] (6) The present invention provides an electrolysis device in any one of (1) to (4) above, wherein the electrolysis device further comprises a backflow prevention check valve disposed in at least one of the first discharge pipe and the second discharge pipe.

[0016] (7) The present invention provides an electrolysis device according to (4), wherein the electrolysis device further comprises a control unit that controls the opening and closing time of the vacuum control valve.

[0017] (8) The present invention provides an electrolysis device in which, in any one of (1) to (7), the electrolysis device is an electrolysis device that electrolyzes carbon dioxide.

[0018] (9) The present invention provides an electrolysis device in which, in any one of (1) to (8), the electrolysis device electrolyzes carbon dioxide to produce one or more selected from the group consisting of carbon monoxide, ethylene, methane, formic acid, hydrocarbons, aldehydes, and alcohols.

[0019] (10) The present invention provides a method for operating an electrolysis device comprising the steps of: discharging a gas generated from an electrolysis stack to the outside of the electrolysis stack through a first discharge pipe (S1); separating the gas discharged in step (S1) and the liquid discharged together with the gas by a gas-liquid separation pipe (S2); and discharging the gas separated in step (S2) to the outside by a vacuum gas discharger and introducing the liquid separated in step (S2) into the electrolysis stack (S3), wherein step (S1) is performed by repeatedly changing the inside of the first discharge pipe to a vacuum and non-vacuum state by a vacuum control valve. Effects of the invention

[0021] According to the electrolysis device of the present invention, oxygen gas generated inside the cell and / or stack can be rapidly discharged to the outside of the cell and / or stack by an external physical force, thereby increasing the efficiency of carbon dioxide electrolysis of the electrolysis device including the cell and / or stack.

[0022] According to the method of operation of the electrolysis device of the present invention, oxygen gas generated by the OER reaction is rapidly discharged by a pulse effect inside a discharge pipe connected to the outside of the cell and / or stack, thereby minimizing factors that interfere with the electrochemical reaction and increasing the electrolysis efficiency. Brief explanation of the drawing

[0024] Figure 1 shows a schematic diagram of a conventional electrolysis device. FIG. 2 is a schematic diagram of the electrolysis apparatus of the present invention, including an electrolysis stack, a gas-liquid separation tube, a vacuum gas exhauster, and a vacuum control valve. FIG. 3 is a schematic diagram of an electrolysis device of the present invention that further includes a control unit in the electrolysis device according to FIG. 2. FIG. 4 is a schematic diagram of the electrolysis apparatus of the present invention, which further includes a gas-liquid separator in the electrolysis apparatus according to FIG. 3. Specific details for implementing the invention

[0025] Hereinafter, the present invention will be described in more detail to aid in understanding the invention. In this case, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0026] The terms used in this specification are used merely to describe exemplary embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0027] In this specification, terms such as “comprising,” “comprising,” or “having” are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should not be understood as precluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0029] electrolysis device

[0030] The electrolysis device of the present invention comprises an electrolysis stack (10), a first discharge pipe (1) through which gas and liquid are discharged to the outside of the electrolysis stack (10), a gas-liquid separation pipe (20) connected to the electrolysis stack (10) through the first discharge pipe, a vacuum gas discharger (30) connected to the gas-liquid separation pipe (20) through a second discharge pipe (2), and a vacuum control valve (40) disposed in the second discharge pipe (2).

[0031] The electrolysis stack (10) may include one electrolysis cell or two or more electrolysis cells, and the electrolysis cell may include an anode, a cathode, an electrolyte, and a separator placed between the cathode and the anode. If the electrolysis stack (10) includes two or more electrolysis cells, the electrolysis cells may form a structure stacked in series. The electrolysis stack (10) can produce a desired substance through electrochemical conversion of supplied carbon dioxide, and, for example, can produce carbon monoxide. The anode acts as an oxidation electrode to oxidize water and generate oxygen, and the cathode acts as a reduction electrode to react with electrons transferred from the anode to produce a product. In this case, the reaction of oxidizing water to generate oxygen is called the Oxygen Evolution Reaction (OER).

[0032] The oxygen gas generated through the above oxygen evolution reaction can form bubbles between the electrode catalyst and the separator, and the formed bubbles can hinder the progress of electrochemical conversion, that is, the electrolysis reaction.

[0033] The above gas may be oxygen gas produced by an oxygen evolution reaction, and the above liquid may be unreacted liquid water.

[0034] Meanwhile, FIG. 1 shows a schematic diagram of a conventional electrolysis device. Referring to FIG. 1, the conventional electrolysis device includes only a gas-liquid separator (50-1) that separates oxygen gas and liquid water discharged from an electrolysis stack (10-1) without any additional external devices or components. The oxygen gas and liquid water are mixed and moved to the gas-liquid separator (50-1) through a first discharge pipe (1-1), the oxygen gas separated in the gas-liquid separator is discharged to the outside through a second discharge pipe (2-1), and the liquid water separated in the gas-liquid separator is recirculated back into the electrolysis stack (10-1) through an inlet pipe (3-1) by a pump (200-1).

[0035] In conventional electrolysis devices, to remove the oxygen gas, the oxygen gas bubbles were removed by increasing the flow rate of the electrolyte introduced into the anode, changing the pattern shape of the cell flow path so that oxygen gas does not adhere to it, or modifying the surface of the electrode or separator. However, there was a limit to the efficiency of removing oxygen gas by only changing the internal structure and material of the electrolysis stack (10-1).

[0036] FIG. 2 is a schematic diagram of an electrolysis apparatus of the present invention including an electrolysis stack, a gas-liquid separation tube, a vacuum gas exhauster, and a vacuum control valve. Referring to FIG. 2, the present invention adds a vacuum gas exhauster (30) to the outside of the electrolysis stack (10) so that the oxygen gas inside the electrolysis stack (10) can be discharged more quickly by drawing the oxygen gas from the outside of the electrolysis stack (10), thereby further improving the efficiency of the electrolysis reaction.

[0037] According to one embodiment of the present invention, the electrolysis device of the present invention may include a discharge pipe and an inlet pipe (6). The discharge pipe is a pipe connecting the electrolysis stack (10), the gas-liquid separation pipe (20), the vacuum gas exhauster (30), and the gas-liquid separator (50), and represents a flow path through which oxygen gas and / or liquid water discharged from the electrolysis stack (10) travels. Specifically, the discharge pipe includes a first discharge pipe (1) connecting the electrolysis stack (10) and the gas-liquid separation pipe (20), a second discharge pipe (2) connecting the gas-liquid separation pipe (20) and the vacuum gas exhauster (30), a third discharge pipe (3) connecting the gas-liquid separation pipe (20) and the gas-liquid separator (50), a fourth discharge pipe (4) connecting the gas-liquid separator (50) and the outside of the electrolysis device, and a fifth discharge pipe (5) connecting the vacuum gas exhauster (30) and the fourth discharge pipe (4).

[0038] The above inlet pipe (6) refers to a pipe connecting the gas-liquid separator (50) and the electrolysis stack (10), and specifically, it refers to a flow path through which liquid water separated from oxygen gas through the gas-liquid separation pipe (20) and / or the gas-liquid separator (50) is recirculated and re-introduced into the electrolysis stack (10).

[0039] The above discharge pipe and inlet pipe (6) may be in the form of cylindrical tubes, and may have a diameter of 0.25 in (about 1.905 cm) or more, 0.3 in or more, 0.4 in or more, 0.5 in or more, 2 in (about 5.08 cm) or less, 1.9 in or less, 1.8 in or less, 1.7 in or less, 1.6 in or less, or 1.5 in or less, and the ratio of the diameter of the above discharge pipe and inlet pipe (6) to the diameter of the above gas-liquid separation pipe may be 1:1 to 5. Specifically, it may be 1:1.2 to 4.8, 1:1.4 to 4.6, 1:1.6 to 4.4, 1:1.8 to 4.2, or 1:2 to 4.

[0040] In addition, the pressure inside the cell, stack, and tube may be 0.1 bar or more and 10 bar or less. Specifically, it may be 0.1 bar or more, 0.2 bar or more, 0.4 bar or more, 0.5 bar or more, 0.7 bar or more, 0.9 bar or more, 1 bar or more, 10 bar or less, 9 bar or less, 8 bar or less, 7 bar or less, 5 bar or less, 4 bar or less, 3 bar or less, and 2 bar or less. When the internal pressure satisfies the above conditions, smooth gas discharge can be controlled without sudden pressure changes in the discharge tube.

[0042] According to one embodiment of the present invention, the electrolysis device of the present invention includes the gas-liquid separation tube (20), and the gas-liquid separation tube (20) may be connected to the electrolysis stack (10) through the first discharge tube (1). The gas-liquid separation tube (20) may separate oxygen gas discharged from the electrolysis stack (10) and water in a liquid state, and the oxygen gas separated from the gas-liquid separation tube (20) may be discharged to the outside by the vacuum gas discharger (30), and the water in a liquid state separated from the gas-liquid separation tube (20) may be introduced into the electrolysis stack (10).

[0043] Considering the difference in specific gravity between the gas and the liquid, the gas-liquid separation tube (20) allows oxygen gas to move in the upper portion based on the cross-sectional area of ​​the gas-liquid separation tube (20), and allows liquid water to move in the lower portion based on the cross-sectional area of ​​the gas-liquid separation tube (20). A second discharge tube (2) may be connected to the upper portion of the gas-liquid separation tube (20) so that the oxygen gas can be discharged to the outside by the vacuum gas discharger (30). Oxygen gas and liquid water that are not separated through the gas-liquid discharge tube may be transferred to a gas-liquid separator (50) connected to a third discharge tube (3), and finally, oxygen gas and liquid water can be separated in the gas-liquid separator (50).

[0044] The gas-liquid separation tube (20) may be in the form of a cylindrical tube and may be about 2 times or more, 2.2 times or more, 2.4 times or more, 2.6 times or more, 2.8 times or more, 3 times or more, 3.2 times or more, 5 times or less, 4.8 times or less, 4.6 times or less, 4.4 times or less, 4.2 times or less, 4 times or less, and 3.8 times or less than the total volume of the final stack. In addition, the diameter of the gas-liquid separation tube (20) may be 1 in or more, 1.2 in or more, 1.4 in or more, 1.7 in or more, 1.9 in or more, 2 in or more, 10 in or less, 9 in or less, 8 in or less, 7 in or less, 6 in or less, and the gas-liquid separation tube (20) may be larger than the diameter of the discharge tube and the inlet tube. If the above conditions are satisfied, the gas-liquid separation reaction is carried out smoothly, and an appropriate volume of the electrolysis device can be formed.

[0045] According to one embodiment of the present invention, the electrolysis device of the present invention includes the vacuum gas exhauster (30), and the vacuum gas exhauster (30) may serve to inhale oxygen gas that is discharged from the electrolysis stack (10) and separated by the gas-liquid separation tube (20). The electrolysis device of the present invention may further include a vacuum pump (100), and the vacuum gas exhauster (30) may be connected to the vacuum pump (100) to continuously maintain a vacuum state and may rapidly inhale oxygen gas using the pressure difference with the electrolysis stack (10). The vacuum gas exhauster (30) may maintain a low vacuum state by the vacuum pump (100), and the pressure of the low vacuum state may be 760 Torr or less, 1 Torr or more, or 0.1 Torr or more.

[0046] The present invention allows for a reduction in pump (200) power consumption compared to a conventional electrolysis device that separates oxygen gas and liquid water using only a gas-liquid separator (50) by placing the vacuum gas exhauster (30) outside the electrolysis stack (10), and enables faster and more efficient removal of oxygen gas from outside the electrolysis stack (10) through physical force. The diameter (30) of the vacuum gas exhauster may be the same diameter as the exhaust pipe.

[0047] According to one embodiment of the present invention, the electrolysis device of the present invention includes the vacuum control valve (40), and the vacuum control valve (40) may be disposed in the second discharge pipe (2). The vacuum control valve (40) is repeatedly opened and closed at regular intervals to change the interior of the first discharge pipe (1) and the second discharge pipe (2) into a vacuum or non-vacuum state, and to provide a vibration effect inside the first discharge pipe (1) and the second discharge pipe (2). Due to the vibration effect, the pressure difference between the vacuum gas discharger (30) and the electrolysis stack (10) can repeatedly increase and decrease, and in this case, the oxygen gas intake efficiency from the electrolysis stack (10) can be further improved.

[0048] FIG. 3 is a schematic diagram of an electrolysis device of the present invention that further includes a control unit in the electrolysis device comprising an electrolysis stack, a gas-liquid separation tube, a vacuum gas exhauster, and a vacuum control valve. Referring to FIG. 3, the electrolysis device of the present invention may further include a control unit (70) that controls the opening and closing of the vacuum control valve (40). The control unit (70) is connected to the vacuum control valve (40) and can automatically control the opening and closing of the vacuum control valve (40). Specifically, by inputting the time for opening and closing the vacuum control valve (40) into the control unit (70), the opening and closing of the vacuum control valve (40) can be automatically controlled. The opening and closing times of the vacuum control valve (40) may each be independently 10 seconds or more, 20 seconds or more, 30 seconds or more, 40 seconds or more, 50 seconds or more, 10 minutes or less, 9 minutes or less, 8 minutes or less, 7 minutes or less, 6 minutes or less, 5 minutes or less, 4 minutes or less, 3 minutes or less, 2 minutes or less, and 1 minute or less.

[0049] FIG. 4 is a schematic diagram of the electrolysis device of the present invention, which further includes a control unit in the electrolysis device comprising an electrolysis stack, a gas-liquid separation tube, a vacuum gas exhauster, a vacuum control valve, and a control unit.

[0050] According to one embodiment of the present invention, the electrolysis device may further include a gas-liquid separator (50) between the gas-liquid separation tube (20) and the electrolysis stack (10), and the gas-liquid separator (50) may separate oxygen gas and liquid water that were not separated in the gas-liquid separation tube (20). The gas-liquid separator (50) utilizes the difference in specific gravity between gas and liquid and may serve to separate oxygen gas and liquid water. In particular, it may serve to finally separate oxygen gas and liquid water that were not separated through the gas-liquid separation tube (20) of the present invention. The oxygen gas separated in the gas-liquid separator (50) may be discharged to the outside of the electrolysis device through the fourth discharge tube (4), and the liquid water separated in the gas-liquid separator (50) may be recirculated through a pump (200) and flow into the interior of the electrolysis stack (10). In this case, the liquid water can be moved to the electrolysis stack (10) through the inlet pipe (6).

[0051] According to one embodiment of the present invention, the electrolysis device may further include a backflow prevention check valve disposed in one or more of the first discharge pipe (1) and the second discharge pipe (2) disposed between the vacuum control valve (40) and the electrolysis stack (10). The backflow prevention check valve may serve to prevent backflow of oxygen gas and liquid water when a vibration effect is transmitted into the first discharge pipe (1) and the second discharge pipe (2) through the vacuum control valve (40). The backflow prevention valve may be disposed in either the first discharge pipe (1) or the second discharge pipe (2), and a plurality of backflow prevention check valves may be disposed. It may be preferable for the vacuum control valve (40) to be disposed ahead of the vacuum control valve (40).

[0053] How the electrolysis device operates

[0054] The present invention provides a method of operating an electrolysis device using the electrolysis device described above.

[0055] Since the description of the electrolysis device among the operation methods of the above-mentioned electrolysis device is the same as the above-mentioned content, only the operation method using the above-mentioned electrolysis device will be described below.

[0057] The method of operating an electrolysis device according to the present invention comprises the steps of: discharging oxygen gas generated from an electrolysis stack to the outside of the electrolysis stack through a first discharge pipe (S1); separating the oxygen gas discharged in step (S1) and the liquid water discharged together with the oxygen gas by a gas-liquid separation pipe (S2); and discharging the oxygen gas separated in step (S2) to the outside by a vacuum gas discharger and introducing the liquid water separated in step (S2) into the electrolysis stack (S3). Step (S1) may be performed by repeatedly changing the inside of the first discharge pipe to a vacuum and non-vacuum state by a vacuum control valve.

[0058] Specifically, the above step (S1) can be carried out by proceeding an electrolysis reaction for carbon dioxide in an electrolysis stack and discharging the generated oxygen gas through a discharge pipe. In this case, the oxygen gas can be discharged more efficiently by the vacuum gas discharger. The vacuum gas discharger can maintain a vacuum state by a vacuum pump connected to the vacuum gas discharger, and the vacuum state may be a low vacuum state as described above. In this case, the inside of the discharge pipe can be changed between a vacuum and a non-vacuum state at regular intervals by a vacuum control valve, and the vacuum control valve can be operated by setting the opening and closing times of the vacuum control valve through a control unit.

[0059] The above step (S2) can be performed by separating the liquid water discharged together with the oxygen gas by the gas-liquid separation tube. In this case, due to the difference in specific gravity between the oxygen gas and the liquid water, the oxygen gas may be located at the upper end of the diameter of the gas-liquid separation tube with respect to the direction of gravity, and the liquid water may be located at the lower end of the diameter of the gas-liquid separation tube.

[0060] The above step (S3) can be carried out by moving the oxygen gas to the side of the vacuum gas exhauster and then discharging it to the outside, and by recirculating the liquid water back into the electrolysis stack. In this case, the oxygen gas and liquid water that were not separated in the gas-liquid separation tube can be finally separated through a gas-liquid separator, and the liquid water can be recirculated into the electrolysis stack through a pump.

[0061] Oxygen gas generated inside the electrolysis stack can be mixed with liquid water and discharged outside the electrolysis stack. Due to the pressure difference caused by the vacuum gas exhauster, the oxygen gas and liquid water move through the first discharge pipe, and the oxygen gas can be separated into the second discharge pipe and the liquid water into the third discharge pipe through the gas-liquid separation pipe. The oxygen gas can be discharged outside the electrolysis device through the second discharge pipe and the vacuum gas exhauster. In this case, the first and second discharge pipes can be changed to vacuum and non-vacuum states through a vacuum control valve placed in the second discharge pipe, and the movement of the oxygen gas can be made smoother through this state change.

[0062] The liquid water discharged from the electrolysis stack can be recirculated through the gas-liquid separation tube and re-entered into the electrolysis cell. In this case, oxygen gas that was not separated by the gas-liquid separator connected to the gas-liquid separation tube can be separated, and finally, the liquid water from which the oxygen gas has been separated can be re-entered into the electrolysis cell through a pump.

[0064] When electrolysis is carried out using the electrolysis device and operating method of the present invention, oxygen discharge can be facilitated, thereby improving electrolysis efficiency. Specifically, the carbon dioxide conversion rate and carbon monoxide Faraday efficiency can be increased, and the overvoltage can be lowered.

[0066] Electrolysis stack

[0067] The electrolysis stack of the present invention may include one or more electrolysis cells, and the electrolysis cell may include an anode, a cathode, an electrolyte, and a separator disposed between the cathode and the anode.

[0068] According to another embodiment of the present invention, the electrolysis stack can be utilized in all fields of electrochemical conversion, and the electrolysis stack may be a device capable of producing useful chemicals through electrochemical conversion such as water electrolysis, and a device capable of reducing and converting carbon dioxide and NOx. Specifically, the electrolysis stack may be included in an electrochemical conversion device that converts carbon dioxide into carbon monoxide and ethylene.

[0069] According to one embodiment of the present invention, the electrolysis refers to the decomposition of a substance through an oxidation-reduction reaction by applying an electric current or voltage to a decomposition reaction that does not occur spontaneously. The anode acts as an oxidation electrode to oxidize water and generate oxygen, and the cathode acts as a reduction electrode, allowing reactants introduced into the cathode to react with electrons transferred from the anode to produce a product. Additionally, the separator may be placed between the anode and the cathode. The separator may be composed of an inert material that does not participate in the electrochemical reaction itself, but may provide a pathway for ions to move between the anode and the cathode and serve to separate physical contact between the anode and the cathode.

[0070] In addition, the anode and the cathode of the electrolysis device of the present invention may each include a catalyst layer. Furthermore, water vapor supplied along with carbon dioxide within the cathode region generates a reduction product through an electroreduction reaction on the cathode surface. Accordingly, the cathode may include a gas diffusion layer to evenly supply humidified carbon dioxide gas to the cathode region. If the cathode includes a hydrophobic gas diffusion layer, the supplied carbon dioxide can be smoothly diffused, distributed, and supplied to the catalyst layer of the cathode. Additionally, the hydrophobic gas diffusion layer effectively prevents moisture condensation, thereby ensuring a continuous and uniform supply of carbon dioxide while allowing the electrolysis reaction to proceed smoothly. Furthermore, the catalyst layer may have a surface, such as a porous structure, to effectively exhibit gas permeability characteristics on its surface.

[0072] According to one embodiment of the present invention, the anode may include a catalyst active for the electrolysis of water, and the catalyst layer of the anode may include one or more selected from the group consisting of Pt, Au, Pd, Ir, Ag, Rh, Ru, Ni, Al, Mo, Cr, Co, Fe, Cu, Ti, W, alloys thereof, or mixed metal oxides, such as Ta2O5, IrO2, etc., for an oxygen evolution reaction. Specifically, the anode in the carbon dioxide electrolysis apparatus of the present invention may include titanium (Ti) coated with iridium oxide (IrO2).

[0073] In addition, since the carbon dioxide reduction reaction occurring at the cathode competes with the hydrogen generation reaction, it may include a catalyst that exhibits activity in the carbon dioxide reduction reaction while having a high voltage required for the hydrogen generation reaction. The catalyst layer of the cathode may include one or more selected from the group consisting of Sn, Sn alloy, Al, Au, Ag, C, Cd, Co, Cr, Cu, Cu alloy, Ga, Hg, In, Mo, Nb, Ni, NiCo2O4, Ni alloy, Ni-Fe alloy, Pb, Rh, Ti, V, W, Zn, and mixtures thereof for the carbon dioxide reduction reaction. Specifically, the cathode in the carbon dioxide electrolysis device of the present invention may include silver (Ag).

[0074] In addition, the separation membrane may include a cation exchange membrane (CEM) or an anion exchange membrane (AEM). Specifically, in the case of the cation exchange membrane, it can act as a barrier that prevents reducing substances generated at the cathode by catalytic action from migrating to the anode and oxidizing, and it may be a separation phase that inhibits the permeation of anions while allowing cations such as hydrogen ions (H+) to permeate. Furthermore, water is oxidized at the anode to produce hydrogen ions (H +...occurs, and an excess of hydrogen ions may cross over to the cathode, saturating the active site of the catalyst responsible for carbon dioxide conversion and potentially reducing the carbon dioxide conversion rate. In this case, the anion exchange membrane can reduce the amount of hydrogen ions crossing over to the cathode. By blocking the movement of hydrogen ions, the anion exchange membrane can prevent the carbon dioxide conversion performance of the cathode from being inhibited, and OH - , HCO3 - , CO3 2- It can mean a separated phase through which anions such as [ ] can pass.

[0075] In addition, the electrolyte is KHCO3, K2CO3, KOH, KCl, KClO4, K2SiO3, Na2SO4, NaNO3, NaCl, NaF, NaClO4, CaCl2, Cs2CO3, H3PO4, KHPO4, guanidinium cation, H + One or more electrolytes selected from the group consisting of aqueous solutions containing cations, alkali metal cations, ammonium cations, alkylammonium cations, halide ions, alkyl amines, borates, carbonates, guanidinium derivatives, nitrites, nitrates, phosphates, polyphosphates, perchlorates, silicates, sulfates, tetraalkylammonium salts, or mixtures thereof may be used. Specifically, the electrolyte of the carbon dioxide electrolysis device of the present invention may include an aqueous solution containing one or more selected from the group consisting of KOH, KHCO3, Cs2CO3, H3PO4, or a mixture of H3PO4 and KHPO4.

[0076] In addition, the gas diffusion layer may use a porous body made of carbon material such as carbon fiber cloth, carbon fiber felt, or carbon fiber paper, or a porous metal body made of a thin metal plate with a mesh structure such as expanded metal or metal mesh, and in the carbon dioxide electrolysis device of the present invention, the gas diffusion layer may use carbon fiber cloth.

[0077] According to one embodiment of the present invention, the electrolysis cell and / or stack can be utilized in any device requiring electrochemical conversion, and in particular, can obtain a desired product by electrochemically decomposing carbon dioxide. Specifically, the electrolysis device can electrolyze carbon dioxide to produce one or more selected from the group consisting of carbon monoxide, ethylene, methane, formic acid, hydrocarbons, aldehydes, and alcohols.

[0079] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Explanation of the symbols

[0081] 1, 2, 3, 4, 5: 1st, 2nd, 3rd, 4th, 5th discharge pipes 6: Inlet pipe 10: Electrolysis Stack 20: Gas-liquid separation column 30: Vacuum gas exhauster 40: Vacuum control valve 50: Gas-liquid separator 70: Control unit 100: Vacuum pump 200: Pump 1-1,2-1: First and second discharge pipes of a conventional electrolysis device 3-1: Inlet pipe of a conventional electrolysis device 10-1: Electrolysis stack of a conventional electrolysis device 50-1: Gas-liquid separator of a conventional electrolysis device 200-1: Pump of a conventional electrolysis device

Claims

Claim 1 An electrolysis device comprising: an electrolysis stack; a first discharge pipe through which gas and liquid are discharged to the outside of the electrolysis stack; a gas-liquid separation pipe connected to the electrolysis stack through the first discharge pipe; a vacuum gas discharger connected to the gas-liquid separation pipe through a second discharge pipe; and a vacuum control valve disposed in the second discharge pipe, wherein the vacuum control valve is repeatedly opened and closed, and the inside of the first discharge pipe is repeatedly changed to a vacuum and non-vacuum state by the vacuum control valve. Claim 2 An electrolysis device according to claim 1, wherein the gas-liquid separation tube separates the gas and liquid discharged from the electrolysis stack. Claim 3 An electrolysis apparatus according to claim 1, wherein the gas separated from the gas-liquid separation tube is discharged to the outside by the vacuum gas discharger, and the liquid separated from the gas-liquid separation tube is introduced into the electrolysis stack. Claim 4 delete Claim 5 An electrolysis device according to claim 1, wherein the electrolysis device further comprises a gas-liquid separator between the gas-liquid separation tube and the electrolysis stack. Claim 6 The electrolysis device of claim 1, wherein the electrolysis device further comprises a backflow prevention check valve disposed in one or more of the first discharge pipe and the second discharge pipe. Claim 7 The electrolysis device of claim 1, wherein the electrolysis device further comprises a control unit for controlling the opening and closing time of the vacuum control valve. Claim 8 The electrolysis device of claim 1, wherein the electrolysis device is an electrolysis device that electrolyzes carbon dioxide. Claim 9 The electrolysis device of claim 1, wherein the electrolysis device electrolyzes carbon dioxide to produce one or more selected from the group consisting of carbon monoxide, ethylene, methane, formic acid, hydrocarbons, aldehydes, and alcohols. Claim 10 A method for operating an electrolysis device comprising: a step (S1) of discharging a gas generated from an electrolysis stack to the outside of the electrolysis stack through a first discharge pipe; a step (S2) of separating the gas discharged in step (S1) and the liquid discharged together with the gas by a gas-liquid separation pipe; and a step (S3) of discharging the gas separated in step (S2) to the outside by a vacuum gas discharger and introducing the liquid separated in step (S2) into the electrolysis stack, wherein step (S1) is performed by repeatedly changing the inside of the first discharge pipe to a vacuum and non-vacuum state by a vacuum control valve.

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