Flow cell reaction system based on tubular transmissive electrodes and method of operation

Abstract

The application relates to a flow cell reaction system and operation method based on a tubular diffusion electrode, and the system comprises a flow cell reactor and a gas-liquid separation device; the flow cell reactor comprises a cathode chamber and an anode chamber separated by a proton exchange membrane; a plurality of multi-channel tubular diffusion electrodes arranged linearly or in an array are arranged in the cathode chamber, the multi-channel tubular diffusion electrodes have a plurality of gas guide channels, the tubular wall is a porous layered wall structure, the outlet end of each multi-channel tubular diffusion electrode is blocked, the inlet end is guided into reaction gas through a gas guide pipe assembly, and the gas is forced to diffuse to the electrode surface through the porous layered wall under the action of pressure to form a gas-liquid-solid three-phase reaction interface; the gas-liquid separation device carries out gas-liquid separation on the gas-liquid mixture output by the cathode chamber, and the separated gas and liquid are respectively returned to the multi-channel tubular diffusion electrode and the cathode chamber to form a loop, and a detection point is arranged on the loop to recover products according to the detection condition. The application realizes efficient and stable operation of an electro-reduction reaction system and is suitable for industrial scale application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrocatalysis, and particularly relates to a flow cell reaction system based on a tubular transmission electrode and an operation method. BACKGROUND

[0002] Traditional flow electrolysis cells as energy conversion devices mainly convert the reaction gas (CO, CO2, N2, nitrogen oxides, CO2 and N2, or CO2 and nitrogen oxides) at the cathode into high-value-added products through an electrochemical process. Although important progress has been made in electroreduction, the low solubility and long mass transfer distance of the reaction gas hinder gas transport, resulting in very limited current density, only tens of mA / cm 2 , far lower than the requirements of industrial applications. One strategy to solve this problem is to coat a high-activity catalyst on a microporous layer decorated with superhydrophobic polytetrafluoroethylene and conductive carbon particles to construct a gas diffusion electrode (GDE). The GDE is a kind of porous membrane electrode, and the GDE integrated with a flow cell or a membrane electrode assembly can facilitate the rapid diffusion of the reaction gas to the active sites, so that the reaction can be operated at an industrial-scale current density (≥300 mA / cm 2 ). However, the degradation of the GDE and the aging and loosening of the binder integrated in the GDE during long-term electrolysis can be observed in the traditional flow electrolysis cell system, which seriously affects the efficient and stable operation of the system. Moreover, due to the small surface / volume ratio of the GDE, the traditional flow electrolysis cell system can only be used for small-scale laboratory experiments at present, and is not suitable for large-scale applications. In addition, the traditional flow electrolysis cell also has the problem that a large amount of reaction gas escapes to the electrolyte on the other side through the gas diffusion layer of the GDE during the reaction process, resulting in the loss of reaction gas flow. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides a flow cell reaction system based on a tubular transmission electrode and an operation method, aiming to realize efficient conversion, stable operation and large-scale application of the flow electrolysis cell.

[0004] The technical scheme adopted by the present application is as follows:

[0005] The application provides a flow cell reaction system based on a tubular diffusion electrode, characterized by comprising a flow cell reactor, a cathode chamber and an anode chamber separated by a proton exchange membrane are arranged in the flow cell reactor, a reaction gas input pipe, a cathode electrolyte input pipe and a gas-liquid output pipe are connected to the cathode chamber and are used for inputting reaction gas, cathode electrolyte and outputting gas-liquid products after reaction respectively, a gas guide pipe assembly and a plurality of multi-channel tubular diffusion electrodes are arranged in the cathode chamber, the inlet of the gas guide pipe assembly is connected to the outlet of the reaction gas input pipe, a plurality of outlets are arranged on the gas guide pipe assembly and are connected to the inlet ends of the plurality of multi-channel tubular diffusion electrodes respectively, and the outlet ends of the multi-channel tubular diffusion electrodes are closed; an anode electrolyte input pipe for inputting anode electrolyte is connected to the anode chamber, an anode electrode is arranged in the anode chamber, and the anode electrode and the multi-channel tubular diffusion electrodes are respectively connected to two ends of a power supply.

[0006] The multi-channel tubular diffusion electrode is made of single metal material and is made through phase inversion and sintering method, has a plurality of channels for gas mass transfer and diffusion and one end is closed, and the pipe wall is a porous layered wall structure; or the catalytic active sites on the surface of the electrode are regulated and controlled through surface reconstruction on the basis of the single metal material.

[0007] Further, a gas-liquid separation device is arranged and is used for separating the gas-liquid mixture output by the cathode chamber, the gas-liquid separation device is provided with a gas-liquid sampling port, a gas outlet and a liquid outlet, the gas-liquid sampling port is connected to the outlet of the gas-liquid output pipe, the gas outlet is connected to the reaction gas input pipe through a first connecting pipe and is then connected to the inlet of the gas guide pipe assembly, and the liquid outlet is connected to the cathode electrolyte input pipe through a second connecting pipe and is then connected to the cathode chamber.

[0008] A first circulating pump, a gas detection point and a first three-way valve are arranged on the first connecting pipe in sequence, and the other outlet of the first three-way valve is used for being connected to a gas product collection end.

[0009] A second circulating pump, a liquid detection point and a second three-way valve are arranged on the second connecting pipe in sequence, and the other outlet of the second three-way valve is used for being connected to a liquid product collection end.

[0010] Further technical solutions are as follows:

[0011] The surface reconstruction includes doping carbon nanotubes, introducing ZIF materials, doping other single metals or doping other heteroatoms to the single metal substrate, or performing surface modification on the multi-channel tubular diffusion electrode of the single metal substrate through in-situ electroetching or in-situ wet chemical method.

[0012] The plurality of multi-channel tubular diffusion electrodes are arranged in a straight line or are distributed in an array.

[0013] The gas guide pipe assembly comprises a main pipe and a plurality of branch pipes connected to the main pipe in parallel, and the outlet of the gas guide pipe assembly is located at the opening end of each branch pipe.

[0014] The gas guide pipe assembly is a metal piece and is connected to the power supply through a wire.

[0015] The first inlet of the reaction gas input pipe is connected to the outlet of the first connecting pipe, and the second inlet of the reaction gas input pipe is connected to an external reaction gas source; the reaction gas input pipe is provided with a first electric valve, a mass flow meter and a gas pressure gauge.

[0016] The inlet of the cathode electrolyte input pipe is connected to a cathode electrolyte storage barrel, and the cathode electrolyte input pipe is provided with a second electric valve.

[0017] The inlet of the anode electrolyte input pipe is connected to an anode electrolyte storage barrel, and the anode electrolyte input pipe is provided with a third electric valve and a liquid pressure gauge.

[0018] The anode chamber is also connected to an exhaust pipe for outputting the gas generated in the anode chamber.

[0019] The gas-liquid separation device is provided with a rotating separation piece for separating the gas-liquid mixture after reaction through rotating motion.

[0020] The application also provides a running method of the flow cell reaction system based on the tubular transparent electrode.

[0021] The cathode electrolyte is input into the cathode chamber through the cathode electrolyte input pipe, the anode electrolyte is input into the anode chamber through the anode electrolyte input pipe, and the external reaction gas is input into the plurality of multi-channel tubular transparent electrodes through the reaction gas input pipe and the gas guide pipe assembly; the power supply is turned on, the reaction gas flows into the channels of the multi-channel tubular transparent electrode and uniformly diffuses to the electrode surface through the porous layered wall to generate an electro-reduction reaction, and the escaped reaction gas, electrolyte and electro-reduction products are discharged into the gas-liquid separation device through the gas-liquid output pipe for gas-liquid separation.

[0022] The gas separated after gas-liquid separation is returned to the multi-channel tubular transparent electrode through the first connecting pipe, the reaction gas input pipe and the gas guide pipe assembly to continue participating in the electro-reduction reaction, forming a closed circulation loop.

[0023] The liquid separated after gas-liquid separation is returned to the cathode chamber through the second connecting pipe and the cathode electrolyte input pipe, forming a closed circulation loop.

[0024] When the product is gas, the reaction gas concentration is detected by a gas detection point, when the reaction gas concentration is less than a first set value, the first three-way valve is switched, the gas in the first connecting pipe is transported to the external gas product collection end, at the same time, the flow of the external reaction gas is adjusted, the total pressure in the multi-channel tubular diffusion electrode is kept unchanged, until the reaction gas concentration detected at the gas detection point is greater than a second set value, the first three-way valve is switched again, the gas in the first connecting pipe reenters the multi-channel tubular diffusion electrode to participate in the electro-reduction reaction;

[0025] When the product is liquid, the liquid product concentration is detected by a liquid detection point, when the liquid product concentration is greater than a third set value, the second three-way valve is switched, the liquid in the second connecting pipe is transported to the external liquid product collection end, at the same time, the cathode electrolyte is supplemented to the cathode chamber through the cathode electrolyte input pipe, until the liquid product concentration detected at the liquid detection point is less than a fourth set value, the second three-way valve is switched again, the liquid in the second connecting pipe reenters the cathode chamber;

[0026] H produced by electrolysis of the anode electrolyte + Through the proton exchange membrane into the cathode chamber, enough H is provided for the electro-reduction reaction in the cathode chamber + At the same time, O2 produced in the anode chamber is discharged through the exhaust pipe.

[0027] The reaction gas includes one of CO, CO2, N2, nitrogen oxides, CO2 and N2 mixed gas, and CO2 and nitrogen oxides mixed gas;

[0028] By using the multi-channel tubular diffusion electrode prepared by using the corresponding material, CO can be directed to convert into methane, methanol, formic acid, ethane, ethylene, ethanol or acetic acid, CO2 can be directed to convert into CO, methane, methanol, formic acid, ethane, ethylene, ethanol or acetic acid, N2 and nitrogen oxides can be directed to convert into ammonia gas or ammonia water, and CO2 and N2 mixed gas and CO2 and nitrogen oxides mixed gas can be directed to convert into urea.

[0029] The beneficial effects of the present application are as follows:

[0030] The present application realizes efficient conversion, stable operation and large-scale application of the system under industrial current density, and has the following advantages:

[0031] Compared with the traditional plate electrode, the multi-channel tubular diffusion electrode has a higher ratio of surface area to volume, and it is convenient to expand a single tubular diffusion electrode to a multi-channel tubular diffusion electrode array, so as to realize the expansion of the electro-reduction reaction scale.

[0032] Compared with the traditional plate flow cell reaction system, the tubular diffusion electrode-based flow cell reaction system of the application is provided with a gas-liquid separation device, combined with an automatic control module and corresponding executing mechanism, including electric valve, three-way valve, gas-liquid detection point, pressure gauge, mass flow meter, etc., to realize automatic operation of the system and efficient separation of gas-liquid products, which can be automatically discharged when the product enrichment concentration reaches the industrial purification concentration, thereby improving the degree of automation of the system and reducing the labor consumption.

[0033] The application can realize directional preparation of different high-value-added products through changing the electrode material of the multi-channel tubular diffusion electrode and regulating the catalytic active sites of the electrode material.

[0034] Other features and advantages of the application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a system structure schematic diagram of the embodiment of the application.

[0036] Figure 2 It is a longitudinal sectional view of the multi-channel tubular diffusion electrode arrangement structure in the application. Figure 1

[0037] It is a transverse sectional view of the multi-channel tubular diffusion electrode arrangement structure in the application. Figure 3 Figure 1

[0038] In the figure: 1, flow cell reactor; 2, gas-liquid separation device;

[0039] 11, cathode chamber; 12, anode chamber; 13, proton exchange membrane; 14, power supply;

[0040] 21, rotating separation piece; 22, gas-liquid sample inlet; 23, gas outlet; 24, liquid outlet; 25, first circulating pump; 26, first three-way valve; 27, gas detection point; 28, second circulating pump; 29, second three-way valve; 210, liquid detection point; 211, first connecting pipe; 212, second connecting pipe;

[0041] 111, gas guide pipe assembly; 112, multi-channel tubular diffusion electrode; 113, reaction gas input pipe; 114, cathode electrolyte input pipe; 115, gas-liquid output pipe; 116, external reaction gas source; 117, first electric valve; 118, mass flow meter; 119, gas pressure gauge; 1110, cathode electrolyte storage barrel; 1111, second electric valve; 1121, channel;

[0042] ​​121, anode electrode; 122, anode electrolyte input pipe; 123, exhaust pipe; 124, anode electrolyte storage tank; 125, third electric valve; 126, liquid pressure gauge. DETAILED DESCRIPTION

[0043] The specific embodiments of the present application will be described below with reference to the accompanying drawings. EMBODIMENT

[0044] Reference Figure 1 The flow cell reaction system based on tubular diffusion electrode of the embodiment comprises a flow cell reactor 1, which is internally provided with a cathode chamber 11 and an anode chamber 12 separated by a proton exchange membrane 13. The cathode chamber 11 is connected with a reaction gas input pipe 113, a cathode electrolyte input pipe 114 and a gas-liquid output pipe 115, which are respectively used for inputting reaction gas, cathode electrolyte and outputting reaction gas-liquid products. The cathode chamber 11 is internally provided with a gas guide pipe assembly 111 and a plurality of multi-channel tubular diffusion electrodes 112. The inlet of the gas guide pipe assembly 111 is connected with the outlet of the reaction gas input pipe 113. The gas guide pipe assembly 111 is provided with a plurality of outlets, which are respectively connected with the inlet ends of the plurality of multi-channel tubular diffusion electrodes 112. The outlet ends of the multi-channel tubular diffusion electrodes 112 are closed.

[0045] The anode chamber 12 is connected with an anode electrolyte input pipe 122 for inputting anode electrolyte. The anode chamber 12 is internally provided with an anode electrode 121 (inert electrode). The anode electrode 121 and the multi-channel tubular diffusion electrodes 112 are respectively connected at both ends of a power supply 14.

[0046] The system further comprises a gas-liquid separation device 2 for separating the reaction gas-liquid products of the cathode chamber 11. The gas-liquid separation device 2 is provided with a gas-liquid sample inlet 22, a gas outlet 23 and a liquid outlet 24. The gas-liquid sample inlet 22 is connected with the outlet of the gas-liquid output pipe 115. The gas outlet 23 is connected with the reaction gas input pipe 113 through a first connecting pipe 211 and then connected with the inlet of the gas guide pipe assembly 111. The liquid outlet 24 is connected with the cathode electrolyte input pipe 114 through a second connecting pipe 212 and then connected with the cathode chamber 11.

[0047] The first connecting pipe 211 is sequentially provided with a first circulating pump 25, a gas detection point 27 and a first three-way valve 26. The other outlet of the first three-way valve 26 is used for being connected with a gas product collection end.

[0048] The second connecting pipe 212 is sequentially provided with a second circulating pump 28, a liquid detection point 210 and a second three-way valve 29. The other outlet of the second three-way valve 29 is used for being connected with a liquid product collection end.

[0049] Specifically, the first inlet of the reaction gas input pipe 113 is connected with the outlet of the first connecting pipe 211, and the second inlet of the reaction gas input pipe 113 is connected with the external reaction gas source 116; the reaction gas input pipe 113 is provided with a first electric valve 117, a mass flow meter 118 and a gas pressure gauge 119.

[0050] Specifically, the inlet of the cathode electrolyte input pipe 114 is connected with the cathode electrolyte storage barrel 1110, and the cathode electrolyte input pipe 114 is provided with a second electric valve 1111.

[0051] Specifically, the inlet of the anode electrolyte input pipe 122 is connected with the anode electrolyte storage barrel 124, and the anode electrolyte input pipe 122 is provided with a third electric valve 125 and a liquid pressure gauge 126.

[0052] Specifically, the anode chamber 12 is further connected with an exhaust pipe 123 for outputting the gas generated in the anode chamber 12.

[0053] Specifically, the gas-liquid separation device 2 is provided with a rotating separation piece 21 for separating the gas-liquid mixture after reaction through rotating motion.

[0054] Referring to Figure 2 and Figure 3 , the plurality of multi-channel tubular diffusion electrodes 112 are arranged in a straight line or distributed in an array;

[0055] The gas guide pipe assembly 111 includes a main pipe and a plurality of branch pipes connected with the main pipe and arranged in parallel, and the outlet of the gas guide pipe assembly 111 is located at the opening end of each branch pipe; the gas guide pipe assembly 111 is a metal piece and is connected with the power supply 14 through a wire.

[0056] In the embodiment, the multi-channel tubular diffusion electrode 112 is made by phase inversion and sintering method, and the specific preparation method includes:

[0057] The silver powder, N-methyl pyrrolidone and the binder are mixed in proportion and ball milled to prepare a film solution;

[0058] The film solution is subjected to vacuum degassing treatment;

[0059] The film solution after vacuum degassing treatment is used as a shell solution, and a coagulant is used as a core solution, which are extruded into water through the spinning head of a spinning equipment to obtain a multi-channel tubular diffusion electrode precursor;

[0060] The precursor is first subjected to sintering treatment at high temperature and then subjected to reduction treatment in a hydrogen atmosphere, so as to form a silver-based material multi-channel tubular diffusion electrode which can be used to realize electrocatalytic CO2 reduction and directional conversion into CO;

[0061] The obtained multi-channel tubular diffusion electrode has a plurality of tubular channels, and the wall of the tubular channel is a porous layered wall.

[0062] The multi-channel tubular diffusion electrode 112 has a plurality of (4 in this embodiment) channels 1121, the inlet of the channel 1121 is connected with the outlet of the gas guide pipe assembly 111, and the outlet is closed. The wall of the multi-channel tubular diffusion electrode is a porous layered wall structure, that is, the pipe wall has multiple layers and multiple pores, thereby facilitating the diffusion of the gas.

[0063] During operation, the reaction gas is introduced into the channels 1121 of the multi-channel tubular diffusion electrode 112 through the gas guide pipe assembly 111. Since the outlet of the channel 1121 is closed, the reaction gas flows along the channel 1121 and is uniformly diffused to the surface of the electrode through the porous layered wall. The flow direction of the gas flow is shown by the arrow in Figure 2 and Figure 3 . The surface of the multi-channel tubular diffusion electrode 112 forms a gas-liquid-solid three-phase reaction interface, and the reaction gas undergoes an electro-reduction reaction at the reaction interface.

[0064] The embodiment also provides a running method of the flow cell reaction system based on the tubular diffusion electrode. The multi-channel tubular diffusion electrode 112 used is a silver-based material, which can realize the directional conversion of CO2 into CO. The method includes the following procedures:

[0065] The second electric valve 1111 is opened, the cathode electrolyte in the cathode electrolyte storage tank 1110 is input into the cathode chamber 11 through the cathode electrolyte input pipe 114 and is filled, and the multi-channel tubular diffusion electrode 112 is immersed therein;

[0066] The third electric valve 125 is opened, the anode electrolyte in the anode electrolyte storage tank 124 is input into the anode chamber 12 through the anode electrolyte input pipe 122 and is filled, and the anode electrode 121 is immersed therein;

[0067] The first electric valve 117 is opened, the reaction gas CO2 of the external reaction gas source 116 is input into the plurality of multi-channel tubular diffusion electrodes 112 through the reaction gas input pipe 113 and the gas guide pipe assembly 111, the power supply 14 is turned on, the reaction gas flows into the channels 1121 of the multi-channel tubular diffusion electrode 112 and is uniformly diffused to the surface of the electrode through the porous layered wall to undergo an electro-reduction reaction, and the escaped reaction gas, electrolyte and electro-reduction product are discharged into the gas-liquid separation device 2 through the gas-liquid output pipe 115 for gas-liquid separation;

[0068] The gas after gas-liquid separation is returned to the multi-channel tubular diffusion electrode 112 through the first connecting pipe 211, the reaction gas input pipe 113 and the gas guide pipe assembly 111 under the action of the first circulating pump 25 to continue to participate in the electro-reduction reaction, forming a closed circulation loop;

[0069] The reaction gas concentration is detected by the gas detection point 27. When the reaction gas CO2 concentration is less than a first set value (5% in this embodiment), the first three-way valve 26 is switched to transport the gas product in the first connecting pipe 211 to the external gas product collection end. At the same time, the gas flow of the external reaction gas source 116 is automatically adjusted by the mass flow meter 118 to keep the total pressure in the multi-channel tubular diffusion electrode 112 unchanged until the reaction gas CO2 concentration detected at the gas detection point 27 is greater than a second set value (99% in this embodiment). Then, the first three-way valve 26 is switched again, and the first circulating pump 25 is used to make the gas in the first connecting pipe 211 re-enter the multi-channel tubular diffusion electrode 112 through the reaction gas input pipe 113 to participate in the electro-reduction reaction.

[0070] The liquid (electrolyte) after gas-liquid separation is returned to the cathode chamber 11 through the second connecting pipe 212 and the cathode electrolyte input pipe 114 under the action of the second circulating pump 28, forming a closed circulation loop.

[0071] H + The H + At the same time, the O2 generated in the anode chamber 12 is discharged through the exhaust pipe 123; the third electric valve 125 is automatically adjusted in real time, and the anode electrolyte in the anode electrolyte storage tank 124 is supplemented to the anode chamber 12. Embodiment

[0072] The difference between the flow cell reaction system based on the tubular diffusion electrode of this embodiment and that of embodiment 1 is that:

[0073] The electrode material of the multi-channel tubular diffusion electrode is a copper-based material. Carbon nanotubes are mixed with the film liquid, and the subsequent steps are the same as above, so that the carbon material is used as a conductive support for copper nanoparticles, realizing the surface reconstruction of the multi-channel tubular diffusion electrode of the above-mentioned copper-based material. The electrode after surface reconstruction can realize the catalytic CO2 electro-reduction directional conversion into CH4.

[0074] The operation method of this embodiment is the same as that of embodiment 1, and the reaction gas used is also CO2. The difference lies in the use of a copper-based multi-channel tubular diffusion electrode doped with carbon nanotubes for electro-catalytic CO2 directional conversion into CH4. Embodiment

[0075] The difference between the flow cell reaction system based on the tubular diffusion electrode of this embodiment and that of embodiment 1 is that:

[0076] The electrode material of the multi-channel tubular diffusion electrode is a copper-based material. The structure of the copper-based material surface is modified by in-situ electro-etching to obtain a valley-shaped catalytic active site.

[0077] The in-situ electrolithography method specifically involves placing the obtained copper-based multichannel tubular permeable electrode in an acidic electrolyte and applying a 2 V ( vs Electrochemical etching is performed using an Ag / AgCl voltage to construct valley-like structures on the surface of the electrode material.

[0078] The operating method of this embodiment is the same as that of Example 1, and the reaction gas used is also CO2. The difference is that a copper-based multi-channel tubular permeable electrode with in-situ electro-etching is used to electrocatalyze the directional conversion of CO2 into C2H4. Example

[0079] The difference between the flow cell reaction system based on the tubular permeable electrode in this embodiment and that in Embodiment 1 is:

[0080] The electrode material of the multi-channel tubular permeable electrode is a copper-based material. The surface structure of the copper-based material is modified by in-situ wet chemistry to obtain catalytic active sites with nano-cavity structures.

[0081] The in-situ wet chemical method specifically involves placing the obtained copper-based multichannel tubular permeable electrode in an acidic etching solution and performing a wet chemical reaction for 60 seconds, thereby inducing the formation of a nanocavity structure on the surface of the electrode material.

[0082] The operating method of this embodiment is the same as that of Example 1, and the reaction gas used is also CO2. The difference is that a copper-based multi-channel tubular permeable electrode after in-situ wet chemical reaction is used to electrocatalyze the directional conversion of CO2 into C2H6. Example

[0083] The difference between the flow cell reaction system based on the tubular permeable electrode in this embodiment and that in Embodiment 1 is:

[0084] The electrode material of the multi-channel tubular permeable electrode is copper-based. The structure of the copper-based material surface is modified by in-situ electro-etching to obtain valley-shaped catalytic active sites.

[0085] The operating method of this embodiment is the same as that of Embodiment 1, except that the reaction gas used is CO, and the copper-based multi-channel tubular permeable electrode after in-situ electro-etching can electrocatalyze the directional conversion of CO into CH4. Example

[0086] The difference between the flow cell reaction system based on the tubular permeable electrode in this embodiment and that in Embodiment 1 is:

[0087] The electrode material of the multi-channel tubular permeable electrode is a copper-based material. The surface structure of the copper-based material is modified by in-situ wet chemistry to obtain catalytic active sites with nano-cavity structures.

[0088] The operation method of this embodiment is the same as that of embodiment 1, except that the reaction gas used is CO, and the copper-based multi-channel tubular diffusion electrode after in-situ wet chemical reaction can electrocatalyze the directional conversion of CO into C2H4. Embodiment

[0089] The difference between the flow cell reaction system based on the tubular diffusion electrode of this embodiment and that of embodiment 1 is that:

[0090] The electrode material of the multi-channel tubular diffusion electrode is a copper-based material. Graphite carbon nitride is mixed with the film solution, and the subsequent steps are the same as those of embodiment 1. In this way, nitrogen atoms are doped into the copper-based multi-channel tubular diffusion electrode to obtain catalytically active sites doped with nitrogen atoms.

[0091] The operation method of this embodiment is the same as that of embodiment 1, except that the reaction gas used is CO, and the difference is that a copper-based multi-channel tubular diffusion electrode doped with nitrogen atoms is used to electrocatalyze the directional conversion of CO into C2H6. Embodiment

[0092] The difference between the flow cell reaction system based on the tubular diffusion electrode of this embodiment and that of embodiment 1 is that:

[0093] The electrode material of the multi-channel tubular diffusion electrode is a tin-based material. ZIF material is introduced into the tin-based material by immersion to modify the surface structure, obtaining catalytically active sites with rich porous structure.

[0094] The ZIF material is introduced into the tin-based material to modify the surface structure, which specifically includes: placing the obtained tin-based material multi-channel tubular diffusion electrode in the immersion liquid of the ZIF material for immersion reaction, so as to generate rich porous structure on the surface of the electrode material.

[0095] The operation method of the flow cell reaction system based on the tubular diffusion electrode of this embodiment uses a multi-channel tubular diffusion electrode with ZIF material introduced to reconstruct the surface of the tin-based material, to realize the directional conversion of NO into ammonia water or ammonia gas, including the following flow:

[0096] The second electric valve 1111 is opened, and the cathode acidic or alkaline electrolyte in the cathode electrolyte storage tank 1110 is input into the cathode chamber 11 through the cathode electrolyte input pipe 114 and filled, so that the multi-channel tubular diffusion electrode 112 is immersed therein;

[0097] The third electric valve 125 is opened, and the anode acidic or alkaline electrolyte in the anode electrolyte storage tank 124 is input into the anode chamber 12 through the anode electrolyte input pipe 122 and filled, so that the anode electrode 121 is immersed therein;

[0098] The first electric valve 117 is opened, the reaction gas NO from the external reaction gas source 116 is input into the multi-channel tubular diffusion electrode 112 through the reaction gas input pipe 113 and the gas guide pipe assembly 111, the power supply 14 is turned on, the reaction gas flows into the channel 1121 of the multi-channel tubular diffusion electrode 112 and is uniformly diffused to the electrode surface to generate an electro-reduction reaction, the escaped reaction gas, electrolyte and electro-reduction product (ammonia water or ammonia gas) are discharged into the gas-liquid separation device 2 through the gas-liquid output pipe 115 for gas-liquid separation.

[0099] When the anode and cathode electrolytes are acid electrolytes, the product of the electro-reduction of NO is mainly the liquid product ammonia water. Therefore, the liquid separated by the gas-liquid separation device 2 is returned to the cathode chamber 11 through the second connecting pipe 212 and the cathode electrolyte input pipe 114 under the action of the second circulating pump 28, forming a closed circulation loop; the concentration of the liquid product NH4OH is detected at the liquid detection point 210, and when the concentration of the liquid product NH4OH is greater than or equal to a third set value (0.414 g / mL in this embodiment), the second three-way valve 29 is switched to transport the liquid in the second connecting pipe 212 to an external liquid product collection end, and at the same time, the second electric valve 1111 is automatically adjusted to supplement the cathode electrolyte to the cathode chamber 11 through the cathode electrolyte input pipe 114 until the concentration of the liquid product NH4OH detected at the liquid detection point 210 is less than a fourth set value (1 μg / mL in this embodiment), and the second three-way valve 29 is switched again to make the liquid in the second connecting pipe 212 re-enter the cathode chamber 11 through the cathode electrolyte input pipe 114. + + When the anode and cathode electrolytes are acid electrolytes, the product of the electro-reduction of NO is mainly the liquid product ammonia water. Therefore, the liquid separated by the gas-liquid separation device 2 is returned to the cathode chamber 11 through the second connecting pipe 212 and the cathode electrolyte input pipe 114 under the action of the second circulating pump 28, forming a closed circulation loop; the concentration of the liquid product NH4OH is detected at the liquid detection point 210, and when the concentration of the liquid product NH4OH is greater than or equal to a third set value (0.414 g / mL in this embodiment), the second three-way valve 29 is switched to transport the liquid in the second connecting pipe 212 to an external liquid product collection end, and at the same time, the second electric valve 1111 is automatically adjusted to supplement the cathode electrolyte to the cathode chamber 11 through the cathode electrolyte input pipe 114 until the concentration of the liquid product NH4OH detected at the liquid detection point 210 is less than a fourth set value (1 μg / mL in this embodiment), and the second three-way valve 29 is switched again to make the liquid in the second connecting pipe 212 re-enter the cathode chamber 11 through the cathode electrolyte input pipe 114.

[0100] When the anode and cathode electrolytes are acid electrolytes, the product of the electro-reduction of NO is mainly the liquid product ammonia water. Therefore, the liquid separated by the gas-liquid separation device 2 is returned to the cathode chamber 11 through the second connecting pipe 212 and the cathode electrolyte input pipe 114 under the action of the second circulating pump 28, forming a closed circulation loop; the concentration of the liquid product NH4OH is detected at the liquid detection point 210, and when the concentration of the liquid product NH4OH is greater than or equal to a third set value (0.414 g / mL in this embodiment), the second three-way valve 29 is switched to transport the liquid in the second connecting pipe 212 to an external liquid product collection end, and at the same time, the second electric valve 1111 is automatically adjusted to supplement the cathode electrolyte to the cathode chamber 11 through the cathode electrolyte input pipe 114 until the concentration of the liquid product NH4OH detected at the liquid detection point 210 is less than a fourth set value (1 μg / mL in this embodiment), and the second three-way valve 29 is switched again to make the liquid in the second connecting pipe 212 re-enter the cathode chamber 11 through the cathode electrolyte input pipe 114. Embodiment

[0101] The difference between the flow cell reaction system based on the tubular diffusion electrode of this embodiment and the embodiment 8 is:

[0102] ​The electrode material of the multi-channel tubular diffusion electrode is tin-based material, and a bimetallic catalytic site is constructed by introducing copper metal material into the tin-based material.

[0103] The operation method of the embodiment is the same as that of example 8, except that the reaction gas used is N2, and the tin-based multi-channel tubular diffusion electrode with a bimetallic catalytic site is used to electrocatalyze the directional conversion of N2 into ammonia water or ammonia gas. Example

[0104] The difference between the flow cell reaction system based on the tubular diffusion electrode of the embodiment and example 8 is:

[0105] The operation method of the flow cell reaction system based on the tubular diffusion electrode of the embodiment uses a multi-channel tubular diffusion electrode made of copper-based material, and a bimetallic catalytic site is constructed by introducing palladium metal material into the copper-based material to realize the directional conversion of CO2 and N2 into urea, including the following flow:

[0106] The second electric valve 1111 is opened, and the cathode electrolyte in the cathode electrolyte storage tank 1110 is input into the cathode chamber 11 through the cathode electrolyte input pipe 114 and filled to immerse the multi-channel tubular diffusion electrode 112;

[0107] The third electric valve 125 is opened, and the anode electrolyte in the anode electrolyte storage tank 124 is input into the anode chamber 12 through the anode electrolyte input pipe 122 and filled to immerse the anode electrode 121;

[0108] The first electric valve 117 is opened, and the reaction gas CO2 and N2 from the external reaction gas source 116 are input into the multi-channel tubular diffusion electrode 112 through the reaction gas input pipe 113 and the gas guide pipe assembly 111, and the power supply 14 is turned on. The reaction gas flows into the channel 1121 of the multi-channel tubular diffusion electrode 112 and is uniformly diffused to the electrode surface to occur electro-reduction reaction, and the escaped reaction gas CO2 and N2, electrolyte, and electro-reduction product urea are discharged into the gas-liquid separation device 2 through the gas-liquid output pipe 115 for gas-liquid separation;

[0109] The gas after gas-liquid separation is returned to the multi-channel tubular diffusion electrode 112 through the first connecting pipe 211, the reaction gas input pipe 113, and the gas guide pipe assembly 111 under the action of the first circulating pump 25 to continue to participate in the electro-reduction reaction, forming a closed circulation loop;

[0110] The liquid after gas-liquid separation is returned to the cathode chamber 11 under the action of the second circulating pump 28 through the second connecting pipe 212 and the cathode electrolyte input pipe 114, forming a closed circulation loop; the concentration of the liquid product is detected through the liquid detection point 210, when the product urea concentration measured at the liquid detection point 210 is ≥1.05 g / mL, the second three-way valve 29 is switched, the liquid in the second connecting pipe 212 is transported to the external liquid product collection end, and at the same time the second electric valve 1111 is automatically adjusted to supplement the cathode electrolyte to the cathode chamber 11 through the cathode electrolyte input pipe 114, until the urea concentration of the liquid product measured at the liquid detection point 210 is <1 μg / mL, the second three-way valve 29 is switched again, and the liquid in the second connecting pipe 212 reenters the cathode chamber 11 through the cathode electrolyte input pipe 114;

[0111] H + Through the proton exchange membrane 13 into the cathode chamber 11, enough H + At the same time, O2 generated in the anode chamber 12 is discharged through the exhaust pipe 123; the third electric valve 125 is automatically adjusted in real time, and the anode electrolyte in the anode electrolyte storage barrel 124 is supplemented to the anode chamber 12. Embodiment

[0112] The difference between the tubular diffuse electrode-based flow cell reaction system of this embodiment and that of embodiment 10 is:

[0113] The multi-channel tubular diffuse electrode adopts copper-based material, and the structure of the copper-based material surface is modified by in-situ wet chemical method to obtain catalytically active sites with nano-cavity structure.

[0114] The operation method of this embodiment is the same as that of embodiment 10, the difference is that the reaction gas used is a mixture of CO2 and NO, and the difference is that the structure of the copper-based material surface is modified by in-situ wet chemical method to obtain catalytically active sites with nano-cavity structure, which can realize the directional conversion of CO2 and NO into urea.

[0115] During the operation of the system of each of the above embodiments, the electric valve is automatically adjusted in real time, so that the electrolyte is timely supplemented into the anode chamber 12 and the cathode chamber 11.

[0116] Those skilled in the art can understand that the above only describes the preferred embodiments of the present application and is not used to limit the present application, and although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A tubular flow cell reaction system based on a flow-through dispersed electrode, characterized in that, The application relates to a flow cell reactor (1) which is internally provided with a cathode chamber (11) and an anode chamber (12) separated by a proton exchange membrane (13), wherein the cathode chamber (11) is connected with a reaction gas input pipe (113), a cathode electrolyte input pipe (114) and a gas-liquid output pipe (115) for inputting reaction gas, cathode electrolyte and outputting reaction gas-liquid products respectively, the cathode chamber (11) is internally provided with a gas guide pipe assembly (111) and a plurality of multi-channel tubular diffusion electrodes (112), the gas guide pipe assembly (111) is connected with the outlet of the reaction gas input pipe (113), a plurality of outlets are arranged on the gas guide pipe assembly (111) and are connected with the inlet ends of the plurality of multi-channel tubular diffusion electrodes (112) respectively, and the outlet ends of the multi-channel tubular diffusion electrodes (112) are closed; the anode chamber (12) is connected with an anode electrolyte input pipe (122) for inputting anode electrolyte, and the anode chamber (12) is internally provided with an anode electrode (121), wherein the anode electrode (121) and the multi-channel tubular diffusion electrodes (112) are respectively connected at two ends of a power supply (14). The plurality of multi-channel tubular diffusion electrodes (112) are arranged in a straight line or are distributed in an array shape. The multi-channel tubular diffusion electrode (112) is made of single metal material through phase inversion and sintering method, has a plurality of channels (1121) for gas mass transfer and diffusion and one end is closed, and the pipe wall is a porous layered wall structure; or the catalytic active sites on the surface of the electrode are regulated and controlled through surface reconstruction on the basis of the single metal material. The surface reconstruction comprises doping carbon nanotubes, introducing ZIF materials, doping other single metals or doping other heteroatoms to the single metal substrate, or performing surface modification on the multi-channel tubular diffusion electrode (112) of the single metal substrate through in-situ electro-etching or in-situ wet chemical method. The application further relates to a gas-liquid separation device (2) for separating the reaction gas-liquid mixture output from the cathode chamber (11), wherein the gas-liquid separation device (2) is provided with a gas-liquid sampling port (22), a gas outlet (23) and a liquid outlet (24), the gas-liquid sampling port (22) is connected with the outlet of the gas-liquid output pipe (115), the gas outlet (23) is connected with the reaction gas input pipe (113) through a first connecting pipe (211) and is then connected with the inlet of the gas guide pipe assembly (111), and the liquid outlet (24) is connected with the cathode electrolyte input pipe (114) through a second connecting pipe (212) and is then connected with the cathode chamber (11). A first circulating pump (25), a gas detection point (27) and a first three-way valve (26) are sequentially arranged on the first connecting pipe (211), and the other outlet of the first three-way valve (26) is used for being connected with a gas product collecting end. A second circulating pump (28), a liquid detection point (210) and a second three-way valve (29) are sequentially arranged on the second connecting pipe (212), and the other outlet of the second three-way valve (29) is used for being connected with a liquid product collecting end. The reaction gas includes one of CO, CO2, N2, nitrogen oxides, CO2 and N2 mixed gas, and CO2 and nitrogen oxides mixed gas; The anode and the cathode electrolyte are acid electrolyte or alkaline electrolyte.

2. The flow cell reaction system based on tubular diaphanoscopy electrodes according to claim 1, characterized in that, The gas guide pipe assembly (111) comprises a main pipe and a plurality of branch pipes connected to the main pipe and arranged in parallel, and the outlet of the gas guide pipe assembly (111) is located at the opening end of each branch pipe. The gas guide pipe assembly (111) is a metal piece and is connected to the power supply (14) through a wire.

3. The flow cell reaction system based on tubular diaphanoscopy electrodes of claim 1, wherein, The first inlet of the reaction gas input pipe (113) is connected to the outlet of the first connecting pipe (211), and the second inlet of the reaction gas input pipe (113) is connected to the external reaction gas source (116); the reaction gas input pipe (113) is provided with a first electric valve (117), a mass flow meter (118) and a gas pressure gauge (119).

4. The flow cell reaction system based on tubular diaphanoscopy electrode according to claim 1, characterized in that, The inlet of the cathode electrolyte input pipe (114) is connected to the cathode electrolyte storage barrel (1110), and the cathode electrolyte input pipe (114) is provided with a second electric valve (1111).

5. The flow cell reaction system based on tubular diaphanoscopy electrode according to claim 1, characterized in that, The inlet of the anode electrolyte input pipe (122) is connected to the anode electrolyte storage barrel (124), and the anode electrolyte input pipe (122) is provided with a third electric valve (125) and a liquid pressure gauge (126).

6. The flow cell reaction system based on tubular diaphanoscopy electrode according to claim 1, characterized in that, The anode chamber (12) is also connected to an exhaust pipe (123) for outputting the gas generated in the anode chamber (12).

7. The flow cell reaction system based on tubular diaphanoscopy electrode according to claim 1, characterized in that, The gas-liquid separation device (2) is provided with a rotating separation piece (21) for separating the gas-liquid mixture after reaction through rotating motion.

8. A method of operating a flow cell reaction system based on a tubular flow-through electrode according to any one of claims 1 to 7, characterized in that The method comprises the following steps: The cathode electrolyte is input into the cathode chamber (11) through the cathode electrolyte input pipe (114), the anode electrolyte is input into the anode chamber (12) through the anode electrolyte input pipe (122), and the external reaction gas is input into the plurality of multi-channel tubular diffusion electrodes (112) through the reaction gas input pipe (113) and the gas guide pipe assembly (111); the power supply (14) is turned on, the reaction gas flow enters the channels of the multi-channel tubular diffusion electrode (112) and uniformly diffuses to the electrode surface to occur electro-reduction reaction, and the escaped reaction gas, electrolyte and electro-reduction products are discharged into the gas-liquid separation device (2) through the gas-liquid output pipe (115) for gas-liquid separation; The gas after gas-liquid separation returns to the multi-channel tubular diffusion electrode (112) through the first connecting pipe (211), the reaction gas input pipe (113) and the gas guide pipe assembly (111) to continue to participate in the electro-reduction reaction, forming a closed circulation loop; The liquid after gas-liquid separation returns to the cathode chamber (11) through the second connecting pipe (212) and the cathode electrolyte input pipe (114), forming a closed circulation loop. When the product is gas, the reaction gas concentration is detected by the gas detection point (27), when the reaction gas concentration is less than the first set value, the first three-way valve (26) is switched, the gas in the first connecting pipe (211) is transported to the external gas product collection end, at the same time, the flow of external reaction gas is adjusted, the total pressure in the multi-channel tubular diffusion electrode (112) is kept unchanged, until the reaction gas concentration measured at the gas detection point (27) is greater than the second set value, the first three-way valve (26) is switched again, so that the gas in the first connecting pipe (211) reenters the multi-channel tubular diffusion electrode (112) to participate in the electro-reduction reaction; When the product is liquid, the liquid product concentration is detected by the liquid detection point (210), when the liquid product concentration is greater than the third set value, the second three-way valve (29) is switched, the liquid in the second connecting pipe (212) is transported to the external liquid product collection end, at the same time, the cathode electrolyte is supplemented to the cathode chamber (11) through the cathode electrolyte input pipe (114), until the liquid product concentration measured at the liquid detection point (210) is less than the fourth set value, the second three-way valve (29) is switched again, so that the liquid in the second connecting pipe (212) reenters the cathode chamber (11); H generated by the electrolysis of the anolyte + H+ enters the cathode chamber (11) through the proton exchange membrane (13), providing sufficient H+ for the electroreduction reaction within the cathode chamber (11). + Meanwhile, the O2 generated in the anode chamber (12) is discharged through the exhaust pipe (123).

9. The method of operating of claim 8, wherein, By using the multi-channel tubular diffusion electrode (112) prepared by using the corresponding material, CO can be directed to convert into methane, methanol, formic acid, ethane, ethylene, ethanol or acetic acid, CO2 can be directed to convert into CO, methane, methanol, formic acid, ethane, ethylene, ethanol or acetic acid, N2 and nitrogen oxides can be directed to convert into ammonia or ammonia water, and CO2 and N2 mixed gas and CO2 and nitrogen oxides mixed gas can be directed to convert into urea.

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