Electrolytic reactor system for green electricity conversion of electrolytic carbon dioxide

Abstract

The invention discloses an electrolytic reactor system for green electricity conversion of electrolytic carbon dioxide. The electrolytic reactor system comprises a carbon dioxide gas cylinder, a gas humidifier, an electrolytic bath, a dryer and a gas chromatograph which are connected in sequence, the outlet of the gas humidifier is communicated with the cathode of the electrolytic bath; the dryer is connected with a cathode gas outlet of the electrolytic bath; the electrolytic cells are integrated in a parallel stacking mode; the dryer comprises a shell, a cooling layer and an adsorption drying layer, the cooling layer and the adsorption drying layer are arranged in the shell, the cooling layer is arranged close to the gas inlet, and the adsorption drying layer is arranged close to the gas outlet. The MEA electrolytic cells are integrated in a parallel stacking mode, commercialization of the electrochemical CO2 reduction reaction can be promoted, and a great contribution is made for carbon dioxide emission reduction and social zero-carbon economic development.

Description

Technical Field

[0001] The present invention relates to the field of carbon dioxide green electricity conversion, and in particular to an electrolytic stack system for electrolyzing carbon dioxide green electricity conversion. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Energy is an indispensable part of human daily life. At present, fossil fuels (such as coal, oil and natural gas) still dominate human energy needs. The consumption of fossil energy produces a large amount of harmful gases such as carbon dioxide, sulfide and nitrogen oxides, leading to environmental problems such as global warming and acid rain. In order to protect the environment, ensure energy security and promote sustainable economic development, it is urgent to accelerate the development of clean and renewable energy. CO2 conversion technology is one of the favorable ways to reduce CO2 emissions and achieve sustainable development of energy and industrial production in the future.

[0004] CO2 green electricity conversion and utilization technology uses new energy as a driving force to convert CO2 into C1 chemical fuels and multi-carbon chemicals. The electrocatalytic CO2 reduction reaction involves three phases: gas, liquid, and solid. The reaction process is divided into three steps: (1) CO2 gas dissolves into the electrolyte, diffuses and adsorbs on the surface of the catalyst; (2) The transfer of electrons and protons breaks the C=O bond to form CC, CO, and CH bonds; (3) The reaction products desorb from the catalyst surface and diffuse into the electrolyte. At the same time, a side reaction - hydrogen evolution reaction - occurs during the electrocatalytic CO2 reduction reaction to produce hydrogen. Therefore, the mixed gas discharged from the cathode includes CO, H2, and water vapor. For some places of use (such as chemical synthesis), the purity of CO is required to be high, and the content of H2 needs to be strictly controlled. Therefore, it is necessary to adjust the electrolysis process by detecting the composition of the discharged mixed gas to effectively reduce the hydrogen evolution side reaction.

[0005] The inventors found that the mixed gas discharged from the cathode includes CO, H2 and water vapor, and the temperature is relatively high. If gas chromatography is used directly for detection, water vapor will condense during the detection process, interfering with the detection of CO and H2. Even if a dryer is added upstream of the gas chromatograph, due to the high temperature of the mixed gas, it is difficult for the dryer to fully adsorb the water vapor in the mixed gas. When the detection is performed again, the residual water vapor will interfere with the detection of CO and H2. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide an electrolytic stack system for converting carbon dioxide into green electricity.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0008] An electrolytic stack system for electrolyzing carbon dioxide for green electricity conversion, comprising a carbon dioxide gas cylinder, a gas humidifier, an electrolytic cell, a dryer and a gas chromatograph connected in sequence;

[0009] The outlet of the gas humidifier is communicated with the cathode of the electrolytic cell;

[0010] The dryer is connected to the cathode gas outlet of the electrolytic cell;

[0011] The electrolytic cells are integrated in a parallel stacking manner;

[0012] The dryer comprises a shell, and a cooling layer and an adsorption drying layer arranged inside the shell. The cooling layer is arranged close to the gas inlet, and the adsorption drying layer is arranged close to the gas outlet.

[0013] The inventors have found through experiments that using a cooling layer to cool the mixed gas is more conducive to improving the adsorption and drying effect of the mixed gas, and is more conducive to improving the accuracy of CO and H2 content detection when performing gas chromatography detection.

[0014] In some embodiments, the cooling layer is a mesh condensation pipe arranged to cover the cross-section of the shell, and the mesh condensation pipe is connected to a cooling water source.

[0015] Preferably, the number of layers of the mesh condensation pipe is 2-10 layers, preferably 3-5 layers.

[0016] In some embodiments, a guide cover is provided below the cooling layer, and a liquid collecting tray is provided below the guide cover; the guide cover is an inverted cone structure, and its bottom opening is located above the liquid collecting tray;

[0017] A movable baffle is provided at the bottom opening of the liquid collecting tray, and the opening is connected to the liquid outlet pipe. One side of the movable baffle is hinged on the liquid collecting tray, and the bottom of the movable baffle is connected to the inner wall of the liquid outlet pipe through a supporting spring.

[0018] If the mixed gas contains a lot of water vapor, it is easy to condense on the mesh condensation pipe during the cooling process. The condensed liquid is collected in the liquid collection tray through the deflector cover. When the pressure generated by the accumulated water in the liquid collection tray is relatively large, the movable baffle can be pressed open and the water can be discharged through the liquid outlet pipe.

[0019] Preferably, the bottom opening of the liquid collecting tray is arranged at the bottommost part of the liquid collecting tray.

[0020] In some embodiments, the adsorption and desiccant layer is filled with a desiccant, which can be any feasible desiccant.

[0021] In some embodiments, the anode gas outlet of the electrolyzer is connected to a gas-liquid separator, and the liquid outlet of the gas-liquid separator is connected to the inside of the electrolyzer via a pump, so as to recycle the liquid obtained by gas-liquid separation back into the electrolyzer. The electrolyzer is an MEA electrolyzer.

[0022] In some embodiments, the electrolytic cell is formed by stacking 10-80 electrolytic chambers in parallel.

[0023] Preferably, the effective reaction area of ​​each electrolysis chamber is a circular area with a diameter of 10-50 cm.

[0024] Preferably, the cathode of the electrolytic cell is a composite laminated structure of nickel felt-carbon paper, the nickel felt has a porosity of >95% and a pore size of 100-700 μm;

[0025] One side of the carbon paper is compounded with the nickel felt, and the other side is loaded with a carbon black catalyst layer, and the carbon black catalyst layer is arranged toward the side of the ion exchange membrane.

[0026] Preferably, the anode of the electrolytic cell is made of Raney nickel mesh material.

[0027] The beneficial effects achieved by one or more embodiments of the present invention are as follows:

[0028] After the present invention uses a cooling layer to cool the mixed gas, it is more conducive to improving the adsorption and drying effect of the mixed gas. When performing gas chromatography detection, it is more conducive to improving the accuracy of CO and H2 content detection.

[0029] The present invention integrates MEA electrolyzers in parallel stacking and converts carbon dioxide into economic products such as carbon monoxide through green electricity consumption, filling the gap in the application field of MEA device system technology products for commercial high-power electrolysis of carbon dioxide green electricity conversion in China. The present invention can promote the commercialization of electrochemical CO2 reduction reaction, contribute to carbon dioxide emission reduction and realize the development of zero-carbon economy in society. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0031] Figure 1 This is a principle framework diagram of a 5KW MEA electrolysis stack device for electrolyzing carbon dioxide for green electricity conversion according to an embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of the internal structure of a dryer according to an embodiment of the present invention;

[0033] Figure 3It is a schematic diagram of the structure model of the MEA electrolytic cell of a 5KW MEA electrolytic stack device for electrolyzing carbon dioxide for green electricity conversion according to an embodiment of the present invention;

[0034] Figure 4 It is a diagram of the actual assembly of the electrolytic cell of a 5KW MEA electrolytic stack device for electrolyzing carbon dioxide for green electricity conversion according to an embodiment of the present invention;

[0035] Figure 5 This is a cabinet assembly rendering of a 5KW MEA electrolytic stack device for electrolyzing carbon dioxide for green electricity conversion according to an embodiment of the present invention, including an electrolytic cell and other installed accessories.

[0036] Among them, 1. Carbon dioxide cylinder; 2. Pressure reducing valve; 3. Gas flow control valve; 4. Gas humidifier; 5. DC power supply; 6. Pump; 7. Electrolyzer; 8. Gas-liquid separator; 9. Pressure controller; 10. Dryer; 11. Flow meter; 12. Gas chromatograph; 13. Adsorption drying layer; 14. Cooling layer; 15. Flow guide cover; 16. Liquid collection tray; 17. Movable baffle; 18. Support spring. DETAILED DESCRIPTION

[0037] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0038] To facilitate understanding of the embodiments of the present invention, further explanation will be given below by taking specific embodiments as examples in conjunction with the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0039] For better understanding, Figure 1 This is a principle framework diagram of an MEA electrolysis stack device and method for electrolyzing carbon dioxide for green electricity conversion according to an embodiment of the present invention; Figure 2 is a schematic diagram of the internal structure of the dryer; the internal structure of the MEA electrolyzer is as follows Figure 3 As shown; Figure 4 This is the actual assembly effect diagram of the MEA electrolytic stack device; Figure 5 This is the actual effect diagram of the cabinet assembly of the MEA electrolytic stack device, which includes the electrolytic cell and other installed accessories.

[0040] An electrolytic stack system for converting carbon dioxide into green electricity. The system as a whole is divided into three circuits of gas, liquid and electricity and supporting devices, which includes a carbon dioxide supply control system, a carbon dioxide humidification system, a carbon dioxide electrolysis system, a product separation system, a product drying system and a product detection and collection system.

[0041] The carbon dioxide supply control system, carbon dioxide is stored in a carbon dioxide gas cylinder 1, the cathode pipeline starts from a high-pressure gas cylinder, and CO2 is passed into a gas humidifier 4 through a pressure reducing valve 2 and a gas flow controller 3;

[0042] Before normal operation, the cathode pipeline of the system needs to be fully purged by humidified carbon dioxide gas, and the humidified CO2 gas is bubbled into the electrolytic stack as a cathode reactant through a bubbler in the gas humidifier 4, and the anode pipeline is passed into the anode electrolyte through the circulation action of the pump, so that the ion exchange membrane and the catalyst are fully infiltrated in the electrolyte, and the electrolyte is passed into the electrolytic stack as an anode reactant;

[0043] The electrolytic stack is formed by connecting MEA membrane electrode electrolyzers 7 in parallel. The anode, ion exchange membrane and cathode form a zero-gap structure, and the electrode is in direct contact with the ion exchange membrane. Under the control of the gas flow meter, humidified CO2 gas is introduced into the cathode gas phase inlet as a reactant, and the anode inlet is introduced into the anode liquid. The humidified CO2 gas is electrolyzed at the cathode of the electrolytic stack to produce carbon-related economic products such as CO, and oxygen evolution reaction occurs at the anode of the electrolytic stack;

[0044] In the product separation system, the liquid phase outlet of the gas-liquid separator is connected to the anode liquid storage tank to form an anode liquid circulation to directly discharge the anode product oxygen.

[0045] The product drying system and product detection and collection system are as follows: the gas is purified by the carbon dioxide adsorber, the dryer 10, and the oxygen adsorber in sequence; the gas is dehydrated by the dryer, the pressure is released by the pressure regulating valve, and the flow meter is used to measure the gas before entering the gas chromatograph to quantitatively detect the type and concentration of the product; the product is pressurized by the gas compressor and then poured into the synthesis gas storage tank for storage.

[0046] like Figure 2 As shown, the dryer 10 includes a shell and a cooling layer 14 and an adsorption drying layer 13 arranged inside the shell. The cooling layer 14 is arranged near the gas inlet, and the adsorption drying layer 13 is arranged near the gas outlet. The cooling layer 14 is a mesh condensation pipe arranged to cover the cross section of the shell, and the mesh condensation pipe is connected to a cooling water source. The number of layers of the mesh condensation pipe is 2-10 layers, and a guide cover 15 is arranged below the cooling layer, and a liquid collecting pan 16 is arranged below the guide cover 15; the guide cover 15 is an inverted cone structure, and its bottom opening is located above the liquid collecting pan 16;

[0047] The bottom opening of the liquid collecting tray 16 is provided with a movable baffle 17 which can be opened and closed, and the opening is connected to the liquid outlet pipe, one side of the movable baffle 17 is hinged to the liquid collecting tray 16, and the bottom of the movable baffle 17 is connected to the inner wall of the liquid outlet pipe through a supporting spring 18. The bottom opening of the liquid collecting tray 16 is provided at the bottom of the liquid collecting tray 16.

[0048] The adsorption and drying layer 13 is filled with a desiccant.

[0049] The MEA electrolytic stack is integrated by stacking 10-80 electrolytic chambers in parallel, for example, 40 chambers; the pressure in the tank is adjustable from 0-0.5MPa, and the pressure on the anode and cathode sides should be balanced. The temperature is adjustable from room temperature to 80°C;

[0050] The effective reaction area of ​​the electrolysis chamber of the MEA electrolysis stack is a circular area with a diameter of 22.8 cm, the pressure in the tank is 0.1 MPa, and the temperature is maintained at room temperature;

[0051] The cathode of the MEA electrolytic stack is a composite structural material of high-porosity nickel felt-carbon paper, the nickel felt has a porosity of 98% and a pore size of 600 μm, one side of the carbon paper is a gas diffusion layer, and the other side is a carbon black catalyst layer loaded with catalyst, and the catalyst layer faces the ion exchange membrane side;

[0052] The ion exchange membrane is a proton exchange membrane or an anion exchange membrane, such as an X37-50-grade-T anion exchange membrane;

[0053] The MEA electrolytic stack anode is made of Raney nickel mesh material;

[0054] The gas flow controller has a pressure resistance of 1 MPa and a control flow rate of 100 L / min;

[0055] The gas humidifier has a pressure resistance of 1 MPa, and the temperature of the solution in the humidifier can be adjusted from room temperature to 80°C, such as 50°C;

[0056] The anolyte is a KHCO3 carbonate solution with a concentration of 0.1-2M, such as 0.1M;

[0057] The gas pressure controller is used to regulate the cathode gas pressure in the electrolytic cell, and a pressure testing device (and a pressure gauge, etc., to monitor or regulate the cathode gas pressure in the electrolytic cell) should be added in front of it;

[0058] The flow meter has a measuring range of 300L / min, a controllable range of 1%-100%, a pressure resistance of 1MPa, and quantitatively monitors the flow at the inlet of the gas chromatograph to calculate the Faraday efficiency and verify the sealing of the gas path.

[0059] The dryer: dries the gas for testing;

[0060] The gas chromatograph can quantitatively detect the concentration of H2 and CO in the gas. The concentration range of H2 and CO is about 500ppm-20%, and the gas chromatograph should cover this concentration range. In addition, after the gas chromatograph is detected, the gas contains a certain amount of CO and H2, which are dangerous gases and should be discharged or treated in time. Alarms such as CO and H2 should be installed in the laboratory.

[0061] The liquid pressure controller is used to control the pressure on the anode side of the electrolytic cell so that the pressures on the cathode and cathode are balanced;

[0062] The gas-liquid separator separates the anode product (O2) from the electrolyte. The liquid phase outlet is connected to the electrolytic cell to form an electrolyte circulation;

[0063] The pump has an anolyte flow rate of 30 L / min, a controllable range of 1%-100%, and a pressure resistance of 1 MPa;

[0064] The electrolytic stack circuit has an adjustable DC regulated power supply with a maximum power of 6 kW, and the power can be set to 5 kW.

[0065] The present invention innovatively integrates MEA electrolyzers in parallel stacking for the first time, constructing the current largest 5KW commercial MEA electrolyzer system architecture, and converts carbon dioxide into economic products such as carbon monoxide through green electricity consumption, filling the huge gap in the application field of MEA device system technology products for domestic commercial high-power electrolysis of carbon dioxide green electricity conversion.

[0066] The 5KW MEA electrolytic stack device and method for electrolyzing carbon dioxide for green electricity conversion described in the present invention can be manufactured and used in the field of carbon dioxide green electricity conversion.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An electrolytic stack system for electrolyzing carbon dioxide to generate green electricity, characterized in that: It includes a carbon dioxide gas cylinder, a gas humidifier, an electrolyzer, a dryer and a gas chromatograph connected in sequence; The outlet of the gas humidifier is communicated with the cathode of the electrolytic cell; The dryer is connected to the cathode gas outlet of the electrolytic cell; The electrolytic cells are integrated in a parallel stacking manner; The dryer comprises a shell, and a cooling layer and an adsorption drying layer arranged inside the shell. The cooling layer is arranged close to the gas inlet, and the adsorption drying layer is arranged close to the gas outlet.

2. The electrolytic stack system for electrolyzing carbon dioxide to generate green electricity according to claim 1, characterized in that: The cooling layer is a mesh condensation pipe arranged to cover the cross section of the shell, and the mesh condensation pipe is connected to a cooling water source.

3. The electrolytic stack system for electrolyzing carbon dioxide to generate green electricity according to claim 2, characterized in that: The number of layers of the mesh condensation pipe is 2-10 layers, preferably 3-5 layers.

4. The electrolytic stack system for electrolyzing carbon dioxide to generate green electricity according to claim 1, characterized in that: A flow guide cover is arranged below the cooling layer, and a liquid collecting tray is arranged below the flow guide cover; the flow guide cover is an inverted cone structure, and its bottom opening is located above the liquid collecting tray; A movable baffle is provided at the bottom opening of the liquid collecting tray, and the opening is connected to the liquid outlet pipe. One side of the movable baffle is hinged on the liquid collecting tray, and the bottom of the movable baffle is connected to the inner wall of the liquid outlet pipe through a supporting spring.

5. The electrolytic stack system for electrolyzing carbon dioxide to generate green electricity according to claim 4, characterized in that: The bottom opening of the liquid collecting tray is arranged at the bottom of the liquid collecting tray.

6. The electrolytic stack system for electrolyzing carbon dioxide to generate green electricity according to claim 1, characterized in that: The adsorption drying layer is filled with desiccant.

7. The electrolytic stack system for electrolyzing carbon dioxide to generate green electricity according to claim 1, characterized in that: The anode gas outlet of the electrolytic cell is connected to the gas-liquid separator, and the liquid outlet of the gas-liquid separator is communicated with the inside of the electrolytic cell through a pump.

8. The electrolytic stack system for electrolyzing carbon dioxide to generate green electricity according to claim 7, characterized in that: The electrolytic cell is formed by stacking 10-80 electrolytic chambers in parallel, and the effective reaction area of ​​each electrolytic chamber is a circular area with a diameter of 10-50 cm.

9. The electrolytic stack system for electrolyzing carbon dioxide to generate green electricity according to claim 8, characterized in that: The cathode of the electrolytic cell is a composite laminated structure of nickel felt-carbon paper, the nickel felt has a porosity of >95% and a pore size of 100-700 μm; One side of the carbon paper is compounded with the nickel felt, and the other side is loaded with a carbon black catalyst layer, and the carbon black catalyst layer is arranged toward the side of the ion exchange membrane.

10. The electrolytic stack system for electrolyzing carbon dioxide to generate green electricity according to claim 8, characterized in that: The anode of the electrolytic cell is made of Raney nickel mesh material.

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