Synthetic ammonia electrolysis device, synthetic ammonia system and synthetic ammonia method

Abstract

The invention provides a synthetic ammonia electrolysis device, a synthetic ammonia system and a synthetic ammonia method, and relates to the technical field of synthetic ammonia, the synthetic ammonia electrolysis device comprises an electrolysis tube, an anode tube and a cathode catalyst, the electrolysis tube is internally provided with an electrolysis reaction cavity, and the electrolysis tube is provided with a liquid inlet and a liquid outlet; the anode tube is arranged in the electrolytic reaction cavity and is used for connecting a positive electrode of a power supply; the cathode catalyst is arranged in the anode tube and is used for being connected with the negative electrode of the power supply; the cathode catalyst is located in the anode tube, the distance between the cathode catalyst and the anode tube is small, an ion exchange membrane does not exist between the cathode catalyst and the anode tube, the internal resistance of the electrolyte is remarkably reduced, the mass transfer speed of the electrolyte in the electrolyte is high, and the electrolytic efficiency can be remarkably improved; the electrolysis requirement can be met by applying small voltage to the two ends of the synthesis ammonia electrolysis device, and the reaction energy consumption can be reduced; and moreover, the membrane-free modular design is convenient to disassemble and assemble, and industrial expanded application is more facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of ammonia synthesis, and in particular to an ammonia synthesis electrolysis device, an ammonia synthesis system and a method. Background Art

[0002] Ammonia (NH 3 ) can be used as a fertilizer, an industrial chemical and a chemical raw material. The advantages of ammonia, such as high energy density, high hydrogen content and easy storage and transportation, make it an ideal carbon-free energy carrier. Among the technologies known to the inventors, the Haber-Bosch process is currently used for industrial synthesis of NH 3 , which has revolutionized the fertilizer production process and contributed to the unprecedented growth of global food production. However, the Haber-Bosch process needs to be carried out under harsh conditions of high temperature (400 - 500 °C) and high pressure (150 - 300 bar), and this process requires the use of a large amount of fossil resources to produce hydrogen (H 2 ) and energy, with serious energy consumption and a large amount of carbon dioxide gas emissions. Therefore, it is particularly important and urgent to develop new ammonia synthesis technologies driven by renewable resources.

[0003] Currently, electrocatalytic ammonia synthesis technology is considered to be one of the most promising new technologies to replace the Haber-Bosch process because of its mild reaction conditions, zero carbon emissions and green and abundant energy sources, mainly including electrocatalytic nitrogen reduction reaction, electrocatalytic nitrate / nitrite reduction reaction and plasma electrocatalytic tandem, etc. Among the technologies known to the inventors, by using a reverse fuel cell, electrolysis of water can generate H 2 and the nitrogen-hydrogen reaction can generate NH 3 can be combined. However, limited by the strong dissociation energy of N≡N and the low solubility of nitrogen gas (N 2 ) in water, it is difficult to achieve efficient conversion of N 2 to NH 3 under mild conditions. In recent years, electrocatalytic nitrate / nitrite reduction reaction has received extensive attention from scientists due to the low dissociation energy of the N=O bond. However, limited by conventional reaction devices, it has disadvantages such as slow electrolyte mass transfer, high energy consumption, low yield and difficulty in scale-up, making it far from meeting industrial requirements.

[0004] Therefore, based on the overall consideration of the ammonia synthesis system, the inventors innovatively studied a new type of ammonia synthesis technology. Summary of the Invention

[0005] The object of the present invention is to provide an ammonia synthesis electrolysis device, an ammonia synthesis system and a method to solve the problems existing in the above-mentioned prior art. There is no ion exchange membrane between the cathode catalyst and the anode tube, the internal resistance of the electrolyte is significantly reduced, the mass transfer rate of the electrolyte in the electrolyte is fast, the electrolysis efficiency can be significantly improved, and the reaction energy consumption can be reduced; moreover, the membrane-free modular design in the present invention is convenient for disassembly and assembly, and is more conducive to industrial scale-up applications.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] An ammonia synthesis electrolysis device includes an electrolysis tube, an anode tube and a cathode catalyst. An electrolysis reaction cavity is arranged inside the electrolysis tube, and a liquid inlet and a liquid outlet communicating with the electrolysis reaction cavity are arranged on the electrolysis tube; the anode tube is arranged inside the electrolysis reaction cavity, and the anode tube is used to connect to the positive electrode of the power supply; the cathode catalyst is arranged inside the anode tube, and the cathode catalyst is used to connect to the negative electrode of the power supply.

[0008] As an embodiment, anode quick connectors and cathode quick connectors are detachably arranged at both ends of the electrolysis tube. An anode conductive rod is fixed to the anode quick connector, and the end of the anode conductive rod is fixedly connected to the anode tube; a cathode electrode clip is fixed to the cathode quick connector, and the end of the cathode electrode clip fixes the cathode catalyst.

[0009] As an embodiment, through holes for liquid flow are provided on the tube wall of the anode tube; the cathode catalyst is rod-shaped and is coaxially arranged inside the anode tube.

[0010] The present invention also discloses an ammonia synthesis system, including a plasma generator, an activation container, a reflux container and an absorption container. The plasma generator is connected to an air gas source and is used to convert nitrogen and oxygen in the air into nitrogen oxide gas; the activation container is communicated with the exhaust port of the plasma generator; the activation container is used to hold an electrolyte, and the electrolyte absorbs nitrogen oxide gas to generate NO x - electrolyte; the activation container is also communicated with the liquid inlet of the ammonia synthesis electrolysis device as described above; the reflux container is communicated with the liquid outlet of the ammonia synthesis electrolysis device, and is also communicated with the activation container through a ventilation pipe. One end of the ventilation pipe is below the liquid level in the reflux container, and the other end is above the liquid level in the activation container; the absorption container is communicated with the reflux container, and an absorption liquid for absorbing ammonia is held in the absorption container.

[0011] As an embodiment, a plurality of the ammonia synthesis electrolysis devices are included, and the anode tubes and cathode catalysts in the plurality of ammonia synthesis electrolysis devices are connected in series or in parallel.

[0012] As an embodiment, the reflux container is also communicated with the activation container through a liquid reflux pipe; one-way valves are arranged between the liquid outlet and the reflux container and on the liquid reflux pipe.

[0013] As an embodiment, a pumping mechanism for providing power for the flow of the electrolyte is arranged between the activation container and the liquid inlet.

[0014] As an embodiment, a power supply device is further included. The power supply device includes a photovoltaic panel, an energy storage mechanism, a converter, and a DC power supply connected in sequence. The positive pole of the DC power supply is electrically connected to the anode tube, and the negative pole of the DC power supply is electrically connected to the cathode catalyst.

[0015] As an embodiment, an air compressor is further included. The air compressor is communicated with the air inlet of the plasma generator; the power supply device further includes a distribution box electrically connected to the converter, and the distribution box is used to supply power to the DC power supply, the plasma generator, and the air compressor.

[0016] The present invention also discloses a method for synthesizing ammonia, which applies the ammonia synthesis system as described above and includes the following steps:

[0017] 1) The plasma generator converts oxygen and nitrogen in the air into nitrogen oxide gas and introduces the nitrogen oxide gas into the electrolyte in the activation container; 2) The electrolyte in the activation container absorbs the nitrogen oxide gas to generate NO x - electrolyte, and the electrolyte with NO x - electrolyte is introduced into the ammonia synthesis electrolysis device; 3) The ammonia synthesis electrolysis device converts the NO x - electrolyte into NH 3 ; 4) The electrolyte after the reaction flows into the reflux container, and the NH 3 gas precipitates and flows into the absorption container, where it is absorbed by the absorption liquid in the absorption container.

[0018] The present invention has the following technical effects compared with the prior art:

[0019] In the present invention, the cathode catalyst is located inside the anode tube, the distance between the two is small, and there is no ion exchange membrane between the cathode catalyst and the anode tube. The internal resistance of the electrolyte is significantly reduced, and the mass transfer rate of the electrolyte in the electrolyte is fast, which can significantly improve the electrolysis efficiency. At the same time, due to the reduction of the internal resistance of the electrolyte in the electrolysis tube, a smaller voltage can be applied at both ends of the ammonia synthesis electrolysis device to meet the electrolysis requirements, which can reduce the reaction energy consumption. Moreover, the present invention adopts a modular design, which is convenient for disassembly and assembly and is more conducive to industrial large-scale application.

[0020] In other technical solutions of the present invention, the following effects are further achieved:

[0021] In the ammonia synthesis system of the present invention, air is used as a raw material, and NO is generated by the method of plasma-activated air. x - This effectively reduces the raw material cost of ammonia synthesis; and solar energy is used as the energy for power generation, which does not produce greenhouse gases and is more environmentally friendly.

[0022] In the ammonia synthesis electrolysis device of the present invention, the liquid inlet and the liquid outlet are respectively located at both ends of the electrolysis tube. When multiple ammonia synthesis electrolysis devices are used in combination, the electrolyte flows in a serpentine circuit in the multiple ammonia synthesis electrolysis devices, increasing the flow path of the electrolyte, which is beneficial to the full reduction of NO x - electrolytes and ensures the high efficiency of the ammonia synthesis process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 is a cross-sectional view of the mating structure of the anode tube and the anode quick connector in the ammonia synthesis electrolysis device in one embodiment;

[0025] Figure 2 is a cross-sectional view of the mating structure of the cathode catalyst and the cathode quick connector in the ammonia synthesis electrolysis device in one embodiment;

[0026] Figure 3 is a side cross-sectional view of the ammonia synthesis electrolysis device in one embodiment;

[0027] Figure 4 is a top view of the ammonia synthesis electrolysis device in one embodiment;

[0028] Figure 5 is a schematic diagram of the ammonia synthesis system in one embodiment;

[0029] Figure 6 is a schematic diagram of the electrode series connection mode of the ammonia synthesis electrolysis device in one embodiment;

[0030] Figure 7 is a standard curve for measuring the ammonia production rate in the reflux container by the indophenol blue colorimetric method in one embodiment, where a is the absorbance curve of NH 4 Cl standard solution with different concentrations; b is the linearly fitted standard curve;

[0031] Figure 8 In one embodiment, it is the standard curve for measuring the ammonia production rate in the absorption container by the indophenol blue colorimetric method, where a is the absorbance curve of NH 4 Cl standard solution with different concentrations; b is the linearly fitted standard curve;

[0032] Figure 9 In one embodiment, it is the chronoamperometry curve of electrolysis for 1 hour at each potential in the parallel electrode mode of the ammonia synthesis electrolysis device;

[0033] Figure 10 In one embodiment, it is the ammonia production rate and Faraday efficiency of electrolysis for 1 hour at each potential in the parallel electrode mode of the ammonia synthesis electrolysis device;

[0034] Figure 11 In one embodiment, it is the conversion rate and energy consumption of electrolysis for 1 hour at each potential in the parallel electrode mode of the ammonia synthesis electrolysis device.

[0035] Figure 12 In one embodiment, it is the chronopotentiometry curve of electrolysis for 1 hour at each potential in the series electrode mode of the ammonia synthesis electrolysis device;

[0036] Figure 13 In one embodiment, it is the ammonia production rate and Faraday efficiency of electrolysis for 1 hour at each potential in the series electrode mode of the ammonia synthesis electrolysis device;

[0037] Figure 14 In one embodiment, it is the conversion rate and energy consumption of electrolysis for 1 hour at each potential in the series electrode mode of the ammonia synthesis electrolysis device;

[0038] Explanation of reference numerals:

[0039] 1. Anode quick connector; 2. Anode conducting rod; 3. Anode tube; 4. Cathode quick connector; 5. Cathode electrode clamp; 6. Cathode catalyst; 7. Electrolysis tube; 8. Liquid inlet; 9. Liquid outlet; 10. Support; 11. Ammonia synthesis electrolysis device; 12. High-current distribution terminal; 13. DC power supply; 14. DC power supply host computer; 15. Distribution box; 16. Converter; 17. Energy storage mechanism; 18. Photovoltaic panel; 19. Absorption container; 20. Check valve; 21. Return container; 22. Peristaltic pump; 23. Low-temperature constant temperature bath; 24. Activation container; 25. Plasma generator; 26. Air compressor. Detailed implementation manners

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] The purpose of the present invention is to provide an ammonia synthesis electrolysis device, an ammonia synthesis system, and a method to solve the problems existing in the prior art. There is no ion exchange membrane between the cathode catalyst and the anode tube, the internal resistance of the electrolyte is significantly reduced, the mass transfer rate of the electrolyte in the electrolyte is fast, the electrolysis efficiency can be significantly improved, and the reaction energy consumption can be reduced; moreover, the membrane-free modular design in the present invention is convenient for disassembly and assembly, and is more conducive to industrial scale-up applications.

[0042] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0043] Embodiment 1:

[0044] This embodiment discloses an ammonia synthesis electrolysis device 11, including an electrolysis tube 7, an anode tube 3, and a cathode catalyst 6. The electrolysis tube 7 has an electrolysis reaction cavity inside, and the electrolysis tube 7 is provided with a liquid inlet 8 and a liquid outlet 9 communicating with the electrolysis reaction cavity; the anode tube 3 is arranged in the electrolysis reaction cavity, and the anode tube 3 is used to connect to the positive pole of the power supply; the cathode catalyst 6 is arranged inside the anode tube 3, and the cathode catalyst 6 is used to connect to the negative pole of the power supply. A support 10 for support and fixation is also arranged on the outer wall of the electrolysis tube 7. As a specific example, a titanium tube with a ruthenium-iridium oxide coating is used as the anode tube 3, and a transition metal composite oxide grown on a nickel foam substrate is used as the cathode catalyst 6, which also forms a self-supporting structure. The anode tube 3 is coaxially arranged inside the electrolysis tube 7; the liquid inlet 8 and the liquid outlet 9 on the electrolysis tube 7 are respectively located at both ends of the electrolysis tube 7 to ensure that the electrolyte has a longer flow path and extend the electrolysis time. Moreover, the diameter of the anode tube 3 is slightly smaller than the diameter of the electrolysis tube 7, and the gap between the two should not be too large to avoid a large amount of electrolyte flowing through the gap between the anode tube 3 and the electrolysis tube 7 without participating in the electrolysis reaction, which affects the efficiency of electrolytic ammonia synthesis.

[0045] Since the cathode catalyst 6 is located inside the anode tube 3 in this embodiment, the distance between the two is small, and there is no ion exchange membrane between the cathode catalyst 6 and the anode tube 3, the internal resistance of the electrolyte is significantly reduced, and the mass transfer rate of the electrolyte in the electrolyte is fast, which can significantly improve the electrolysis efficiency. At the same time, since the internal resistance of the electrolyte in the electrolysis tube 7 is reduced, a relatively small voltage can be applied across the two ends of the ammonia synthesis electrolysis device 11 to meet the electrolysis requirements, which can reduce the reaction energy consumption. And the membrane-free modular design of the ammonia synthesis electrolysis device 11 in this embodiment is convenient for disassembly and assembly, and is more conducive to industrial scale-up applications.

[0046] As an embodiment, anode quick connectors 1 and cathode quick connectors 4 are detachably arranged at both ends of the electrolysis tube 7. The anode quick connector 1 is fixed with an anode conductive rod 2. One end of the anode conductive rod 2 is fixedly connected to the anode tube 3, and welding or other fixed connection methods can be selected; the other end of the anode conductive rod 2 is exposed for connecting to the positive electrode of the power supply. The cathode quick connector 4 is fixed with a cathode electrode clamp 5. One end of the cathode electrode clamp 5 is fixed with the cathode catalyst 6, and the other end is exposed for connecting to the negative electrode of the power supply.

[0047] As an embodiment, the tube wall of the anode tube 3 has through holes for liquid flow; the cathode catalyst 6 is rod-shaped and is coaxially arranged inside the anode tube 3. In this embodiment, the axial length of the cathode catalyst 6 is not less than the axial length of the anode tube 3; in order to facilitate the accommodation of the cathode catalyst 6, a groove can be provided at the inner end of the anode quick connector 1 for accommodating the part of the cathode catalyst 6 that extends beyond the anode tube 3.

[0048] Embodiment 2:

[0049] This embodiment discloses an ammonia synthesis system, including a plasma generator 25, an activation container 24, a reflux container 21, and an absorption container 19. Among them, the plasma generator 25 is used to convert nitrogen and oxygen in the air into nitrogen oxide gas. The intake end of the plasma generator 25 is connected to an air source, and the exhaust end is communicated with the activation container 24. The activation container 24 is used to hold an electrolyte, and the electrolyte absorbs nitrogen oxide gas to generate NO x -Electrolyte. In this embodiment, the electrolyte is an alkaline aqueous solution. As an example, the electrolyte is a 0.1 - 12 M KOH aqueous solution. To enable better contact between the electrolyte and nitrogen oxides, the exhaust end of the plasma generator 25 is located below the liquid level of the electrolyte in the activation container 24. The activation container 24 is also connected to the liquid inlet 8 of the ammonia synthesis electrolysis device 11 in Embodiment 1; the reflux container 21 is connected to the liquid outlet 9 of the ammonia synthesis electrolysis device 11, and the reflux container 21 is also connected to the activation container 24 through a ventilation pipe. One end of the ventilation pipe is located below the liquid level in the reflux container 21, and the other end is located above the liquid level in the activation container 24. The excessive nitrogen oxide gas introduced into the activation container 24 is discharged into the reflux container 21, and the NH 3 generated by electrolysis in the electrolyte in the reflux container 21 can be blown out. The absorption container 19 is connected to the reflux container 21, and an absorption liquid for absorbing ammonia is contained in the absorption container 19. In this embodiment, the absorption liquid is an acidic aqueous solution. As an example, the absorption liquid is a 0.2 - 12 M HCl solution.

[0050] The ammonia synthesis system may include multiple ammonia synthesis electrolysis devices 11, and the anode tubes 3 and cathode catalysts 6 in the multiple ammonia synthesis electrolysis devices 11 are connected in series or in parallel. When multiple ammonia synthesis electrolysis devices 11 are used in combination, the liquid inlet 8 of one ammonia synthesis electrolysis device 11 is connected to the liquid outlet 9 of another ammonia synthesis electrolysis device 11. When the electrodes of the ammonia synthesis electrolysis device 11 are connected in series, the anode tube 3 in one ammonia synthesis electrolysis device 11 is electrically connected to the cathode catalyst 6 in another ammonia synthesis electrolysis device 11, and multiple ammonia synthesis electrolysis devices 11 are connected in series in this way. Finally, the positive electrode of the power supply is electrically connected to the free anode tube 3, and the negative electrode of the power supply is electrically connected to the free cathode catalyst 6. After multiple ammonia synthesis electrolysis devices 11 are connected, the electrolyte flows in a serpentine circuit in the multiple ammonia synthesis electrolysis devices 11, increasing the flow path of the electrolyte, which is beneficial to the full reduction of NO x - in the electrolyte and ensuring high efficiency in the ammonia synthesis process. When the electrodes of the ammonia synthesis electrolysis device 11 are connected in parallel, the positive electrode of the power supply is simultaneously connected to the anode tubes 3 of multiple ammonia synthesis electrolysis devices 11, and the negative electrode of the power supply is simultaneously connected to the cathode catalysts 6 of multiple ammonia synthesis electrolysis devices 11. Thus, those skilled in the art can connect multiple ammonia synthesis electrolysis devices 11 in series or in parallel according to actual needs, or even form a combined ammonia synthesis electrolysis mechanism by connecting multiple series or parallel ammonia synthesis electrolysis devices 11, and connect multiple combined ammonia synthesis electrolysis mechanisms in parallel or in series. For example, when multiple ammonia synthesis electrolysis devices 11 are connected in parallel, the effect of generating a large current in the circuit with a small-voltage power supply can be utilized, and when multiple ammonia synthesis electrolysis devices 11 are connected in series, the electrolysis reaction speed can be significantly increased and the reaction energy consumption can be reduced.

[0051] In this embodiment, the reflux container 21 is also communicated with the activation container 24 through a liquid reflux pipe, and the electrolyte after the evolved gas is re-refluxed into the activation container 24 for recycling. To avoid the reflux of the electrolyte, check valves 20 are provided between the liquid outlet 9 and the reflux container 21 and on the liquid reflux pipe.

[0052] In this embodiment, a pumping mechanism for providing power for the flow of the electrolyte is provided between the activation container 24 and the liquid inlet 8; as a specific example, the pumping mechanism can be a peristaltic pump 22.

[0053] In this embodiment, the ammonia synthesis system further includes a power supply device, which includes a photovoltaic panel 18, an energy storage mechanism 17, a converter 16, and a DC power supply 13 connected in sequence. The positive electrode of the DC power supply 13 is electrically connected to the anode tube 3, and the negative electrode of the DC power supply 13 is electrically connected to the cathode catalyst 6. The photovoltaic panel 18 is used to collect sunlight, convert solar energy into electrical energy and store it in the energy storage mechanism 17. The stored direct current is converted into alternating current by the converter 16 to supply power to other electrical equipment, such as the peristaltic pump 22. At the same time, the converter 16 is electrically connected to the DC power supply 13, and the DC power supply 13 can convert alternating current into direct current and supply power to the ammonia synthesis electrolysis device 11 through a large current terminal block 12.

[0054] In this embodiment, the ammonia synthesis system further includes an air compressor 26, which is communicated with the air inlet of the plasma generator 25 to provide compressed air for the plasma generator 25. The power supply device further includes a distribution box 15 electrically connected to the converter 16. The distribution box 15 can be equipped with multiple power switches and supply power to the DC power supply 13, the plasma generator 25, and the air compressor 26 respectively, which is more convenient for individually controlling multiple electrical equipment.

[0055] Embodiment 3:

[0056] This embodiment discloses an ammonia synthesis method, which uses the ammonia synthesis system described in Embodiment 2 and includes the following steps:

[0057] 1) The plasma generator 25 converts oxygen and nitrogen in the air into nitrogen oxide gas and introduces the nitrogen oxide gas into the electrolyte in the activation container 24.

[0058] 2) The electrolyte in the activation container 24 absorbs the nitrogen oxide gas to generate NO x - electrolyte, and the electrolyte with NO x - electrolyte is introduced into the ammonia synthesis electrolysis device 11.

[0059] 3) The ammonia synthesis electrolysis device 11 converts NO through an electrocatalytic reaction x -The electrolyte is converted to NH 3 .

[0060] 4) The electrolyte after the reaction flows into the reflux container 21, and NH 3 gas evolution flows into the absorption container 19 and is absorbed by the absorption liquid in the absorption container 19.

[0061] The method for synthesizing ammonia is described below with examples:

[0062] Example 1, multiple ammonia synthesis electrolysis devices 11 are arranged in parallel.

[0063] 1) Insert the anode quick plug and the cathode quick plug into the electrolysis tube 7 to assemble the ammonia synthesis electrolysis device 11. According to actual needs, multiple ammonia synthesis electrolysis devices 11 are connected in parallel, and the ammonia synthesis electrolysis device 11 is connected to the DC power supply 13.

[0064] 2) Pour 2000 mL of 4M KOH electrolyte into each of the activation container 24 and the reflux container 21; pour 2000 mL of 1M HCl absorption liquid into the absorption container 19; start the air compressor 26 and the plasma generator 25 to pre-run for 2 hours so that the electrolyte contains sufficient NO x - for electrocatalytic ammonia synthesis; place the activation container 24 in the water tank of the low-temperature constant temperature bath 23, and set the cooling water temperature to 2°C to avoid too high a temperature of the activation container 24.

[0065] 3) Start the peristaltic pump 22 to pass the electrolyte with NO x - into the ammonia synthesis electrolysis device 11; the DC power supply 13 operates in a constant voltage mode, the output voltage is set to 2.5V - 5.5V, and the electrolysis time is 60 min; when the DC power supply 13 starts to output voltage, turn on the DC power supply upper computer 14, and the DC power supply upper computer 14 is responsible for real-time recording of the output voltage, current, and power.

[0066] 4) After the electrolysis is completed, the obtained chronoamperometry results are as Figure 10 ; take 0.1 mL of the electrolyte and dilute it 10,000 times, take 0.1 mL of the absorption liquid and dilute it 10,000 times, and determine the ammonia production rate by the indophenol blue colorimetric method using an ultraviolet-visible spectrophotometer. Calculate the ammonia production rate according to the standard curve as Figures 8 - 9 shown, when the cell voltage (voltage across a single ammonia synthesis electrolysis device 11) is 2.5 - 5.5V, the ammonia production rate is 12.8 - 43.5 g / h Figure 11 shown, and the Faraday efficiency is 82.1% - 92.5%, and NO -1 to NH 2 - to NH 3The conversion rate is 33.8% - 93.4%, and the energy consumption for ammonia production by electrolysis is 0.39 - 0.76 kWh / mol.

[0067] It can be seen from Figure 11 that in the electrode parallel mode, this example can achieve the effect of low cell voltage and large current, and achieve a high ammonia production rate while ensuring a high Faraday efficiency.

[0068] Example 2, multiple ammonia synthesis electrolysis devices 11 are connected in series.

[0069] 1) Insert the anode quick plug and the cathode quick plug into the electrolysis tube 7 to assemble the ammonia synthesis electrolysis device 11. According to actual needs, connect multiple ammonia synthesis electrolysis devices 11 in series, and connect the ammonia synthesis electrolysis device 11 to the DC power supply 13.

[0070] 2) Pour 2000 mL of 4M KOH electrolyte into each of the activation container 24 and the reflux container 21; pour 2000 mL of 1M HCl absorption solution into the absorption container 19; start the air compressor 26 and the plasma generator 25 to pre-run for 2 hours to make the electrolyte contain sufficient NO x - for electrocatalytic ammonia synthesis; place the activation container 24 in the water tank of the low-temperature constant temperature bath 23, and set the cooling water temperature to 2 °C to avoid the temperature of the activation container 24 being too high.

[0071] 3) Start the peristaltic pump 22 to introduce the electrolyte with NO x - into the ammonia synthesis electrolysis device 11; the DC power supply 13 operates in a constant current mode, with the output current set to 15 A - 35 A and the electrolysis time being 60 min; turn on the DC power supply upper computer 14 simultaneously when the DC power supply 13 starts to output voltage, and the DC power supply upper computer 14 is responsible for recording the output voltage, current, and power in real time.

[0072] 4) After the electrolysis is completed, the obtained chronoamperometry results are as Figure 10 ; take 0.1 mL of the electrolyte and dilute it 10,000 times, take 0.1 mL of the absorption solution and dilute it 10,000 times, and measure the ammonia production rate by the indophenol blue colorimetric method using a UV-visible spectrophotometer. Calculate the ammonia production rate according to the standard curve as Figures 8 - 9 shown. The measured results are as Figure 13 shown. When continuously electrolyzing under the condition of a constant current of 15 - 35 A, the ammonia production rate is 19.7 - 48.2 g / h -1 , the Faraday efficiency is 82.9% - 88.4%, and the conversion rate of NO 2 - to NH 3 is 82.2% - 93.2%, and the energy consumption for ammonia production by electrolysis is 0.42 - 0.47 kWh / mol.

[0073] As can be seen from Figure 13 the above, in the case of the electrode series connection mode of this example, a high ammonia production rate and low energy consumption can be achieved while ensuring a high Faraday efficiency.

[0074] It can be easily concluded from Example 2 and Example 3 of the present invention that the ammonia synthesis system in the present invention uses air as a raw material and generates NO by means of plasma-activated air x - , effectively reducing the raw material cost of ammonia synthesis; and using solar energy for power generation, without generating greenhouse gases, which is more environmentally friendly.

[0075] Adaptations made according to actual needs are all within the protection scope of the present invention.

[0076] Specific examples are applied in the present invention to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A synthetic ammonia electrolysis device, characterized in that: include: An electrolysis tube, wherein an electrolysis reaction chamber is arranged inside the electrolysis tube, and a liquid inlet and a liquid outlet connected to the electrolysis reaction chamber are arranged on the electrolysis tube; an anode tube, the anode tube being arranged in the electrolysis reaction chamber and being used to connect to the positive electrode of a power supply; A cathode catalyst is disposed inside the anode tube and is used to connect to a negative electrode of a power source.

2. The synthetic ammonia electrolysis device according to claim 1, characterized in that: The two ends of the electrolysis tube are detachably provided with an anode quick connector and a cathode quick connector. The anode quick connector is fixed with an anode conductive rod, and the end of the anode conductive rod is fixedly connected to the anode tube; the cathode quick connector is fixed with a cathode electrode clamp, and the end of the cathode electrode clamp is fixed with the cathode catalyst.

3. The synthetic ammonia electrolysis device according to claim 1, characterized in that: The tube wall of the anode tube is provided with a through hole for liquid flow; the cathode catalyst is in a rod shape and is coaxially arranged in the anode tube.

4. A synthetic ammonia system, characterized in that: include: A plasma generator, the plasma generator is connected to an air source and is used to convert nitrogen and oxygen in the air into nitrogen oxide gas; The activation container is connected to the exhaust port of the plasma generator; the activation container is used to contain electrolyte, and the electrolyte absorbs nitrogen oxide gas to generate NO x - electrolyte; the activation container is also connected to the liquid inlet of the synthetic ammonia electrolysis device according to any one of claims 1 to 3; A reflux container, the reflux container is connected to the liquid outlet of the synthetic ammonia electrolysis device, and is also connected to the activation container through a vent pipe, one end of the vent pipe is located below the liquid level in the reflux container, and the other end is located above the liquid level in the activation container; An absorption container is communicated with the reflux container, and an absorption liquid for absorbing ammonia is contained in the absorption container.

5. The ammonia synthesis system according to claim 4, characterized in that: It comprises a plurality of the synthetic ammonia electrolysis devices, wherein the anode tubes and cathode catalysts in the plurality of the synthetic ammonia electrolysis devices are connected in series or in parallel.

6. The ammonia synthesis system according to claim 4, characterized in that: The reflux container is also connected to the activation container through a liquid reflux pipe; a one-way valve is arranged between the liquid outlet and the reflux container and on the liquid reflux pipe.

7. The ammonia synthesis system according to claim 4, characterized in that: A pumping mechanism for providing power for the flow of electrolyte is arranged between the activation container and the liquid inlet.

8. The ammonia synthesis system according to claim 4, characterized in that: It also includes a power supply device, which includes a photovoltaic panel, an energy storage mechanism, a converter and a DC power supply connected in sequence, the positive electrode of the DC power supply is electrically connected to the anode tube, and the negative electrode of the DC power supply is electrically connected to the cathode catalyst.

9. The ammonia synthesis system according to claim 8, characterized in that: It also includes an air compressor, which is connected to the air inlet of the plasma generator; the power supply device also includes a distribution box electrically connected to the converter, and the distribution box is used to supply power to the DC power supply, the plasma generator, and the air compressor.

10. A method for synthesizing ammonia, characterized in that: The ammonia synthesis system according to any one of claims 4 to 9 comprises the following steps: 1) The plasma generator converts oxygen and nitrogen in the air into nitrogen oxide gas, and passes the nitrogen oxide gas into the electrolyte in the activation container; 2) The electrolyte in the activation container absorbs nitrogen oxide gas to generate NO x - electrolyte and will have NO x - The electrolyte solution is passed into the synthetic ammonia electrolysis device; 3) The synthetic ammonia electrolysis device converts NO x - The electrolyte is converted to NH3; 4) The electrolyte after the reaction flows into the reflux container, and the NH3 gas precipitates and flows into the absorption container, and is absorbed by the absorption liquid in the absorption container.

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