CN114950088B - A device, usage method and application of electrochemical reduction technology coupled with gas-liquid separation membrane technology for resource-based treatment of nitrogen oxide waste gas - Google Patents

Abstract

The invention relates to a waste gas treatment device, in particular to a device for recycling treatment of nitrogen oxide waste gas by an electrochemical reduction technology coupled with a gas-liquid separation membrane technology, a use method and application thereof, comprising an electrochemical reactor formed by sequentially attaching a cathode air chamber, a gas diffusion cathode, a catholyte chamber, an anion exchange membrane, a gas diffusion anode and an anolyte chamber, and an ammonia recovery device communicated with the catholyte chamber through a conveying pipeline; the gas inlet system is communicated with the cathode gas chamber, the electrolyte liquid inlet system is communicated with the anolyte chamber, and the power supply is connected with the gas diffusion cathode and the gas diffusion anode; the ammonia recovery device is internally provided with a hollow fiber membrane, one side of the hollow fiber membrane is provided with electrolyte which is input by a catholyte chamber, and the other side of the hollow fiber membrane is provided with absorption liquid. Compared with the prior art, the method has the advantages of low energy consumption for treating the nitrogen oxide waste gas, high electrode activity, selectivity and recycling treatment efficiency, no secondary pollution and suitability for industrialized popularization.

Description

An electrochemical reduction technology coupled with gas-liquid separation membrane technology to treat nitrogen oxidation as a resource Devices, methods of use and applications of waste gas

Technical field

The present invention relates to an exhaust gas treatment device, and specifically relates to a device, usage method and application for recycling nitrogen oxide exhaust gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology.

Background technique

In China, nitrogen oxide pollutants mainly come from flue gas emissions from non-ferrous smelting and thermal power industries. They are one of the important precursors that cause environmental problems such as photochemical smog, acid rain and greenhouse effects. Their large emissions have seriously threatened natural nitrogen. Circulation and safety of human life. At present, traditional selective catalytic reduction technology can realize the harmless treatment of nitrogen oxides to nitrogen, but it has problems such as huge energy consumption and secondary pollution, and its application scope is limited. More importantly, from the perspective of natural nitrogen cycle, nitrogen oxides in flue gas are also a nitrogen resource. Compared with the strategy of converting nitrogen oxides into nitrogen gas, the selective conversion of nitrogen oxides into high value-added ammonia and the strategy of ammonia recovery are more in line with the national "waste resource utilization" strategic needs and are of great significance in practical applications.

Compared with traditional methods, electrochemical reduction technology has the advantages of simple operation, strong controllability, economical applicability, and mild reaction conditions, and is expected to realize the selective conversion of nitrogen oxides to ammonia. However, electrochemical reduction technology faces the problem of low electrode activity and selectivity, and its application scope is temporarily limited. In addition, the enrichment and recovery of ammonia converted from nitrogen oxides is an important link in the resource utilization of nitrogen oxides. In the actual electrochemical reduction of nitrogen oxides, the coexistence of anions/cations (chloride ions, sulfate ions, and sodium ions) in the solution will interfere with the selective recovery of ammonia. The current industrial ammonia steaming-stripping method has problems such as high energy consumption, incomplete release of ammonia in the solution, and low ammonia recovery rate (<60%).

Contents of the invention

The purpose of the present invention is to solve at least one of the above problems and provide an electrochemical reduction technology coupled with gas-liquid separation membrane technology resource-based treatment of nitrogen oxide exhaust gas device, use method and application, achieving effective treatment of nitrogen oxide pollutants , while realizing resource utilization of nitrogen oxides.

The object of the present invention is achieved through the following technical solutions:

The first aspect of the present invention discloses a device for resource-based treatment of nitrogen oxide waste gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology, including a cathode gas chamber, a gas diffusion cathode, a cathode liquid chamber, an anion exchange membrane, and a gas diffusion anode. and an electrochemical reactor formed by sequentially fitting the anolyte chambers and an ammonia recovery device connected to the catholyte chamber through a transportation pipeline;

The electrochemical reactor also includes an air inlet system connected to the cathode gas chamber, an electrolyte inlet system connected to the anolyte chamber, and a power supply connected to the gas diffusion cathode and the gas diffusion anode respectively;

The ammonia recovery device is provided with a hollow fiber membrane, one side of the hollow fiber membrane passes the electrolyte input from the catholyte chamber, and the other side passes the absorption liquid;

The electrochemical reactor converts nitrogen oxides in the flue gas into ammonia. The ammonia is input into the ammonia recovery device along with the electrolyte in the catholyte chamber through the transportation pipeline, and enters the absorption liquid through the hollow fiber membrane and then leaves with the absorption liquid. Ammonia recovery device, the remaining electrolyte is returned to the catholyte chamber.

Preferably, the gas diffusion cathode is based on titanium foam, and the surface is loaded with transition metal single atoms or nanocluster active materials; the pore diameter of the gas diffusion cathode is 50-100 μm.

Preferably, the transition metal single atom or nanocluster active material includes one or more of manganese, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum and gold. species, the mass loading is 0.01-20%.

Preferably, the electrolyte is one or more of sodium hydroxide, potassium hydroxide, sodium sulfate and potassium sulfate, with a concentration of 0.1-5mol/L; the absorption solution is sulfuric acid, nitric acid and hydrochloric acid. One or more, the concentration is 0.1-5mol/L.

Preferably, the gas diffusion anode is a ruthenium-iridium coated titanium electrode, and the coating thickness is 8-15 μm.

Preferably, the hollow fiber membrane is a hydrophobic porous membrane, the inner diameter of the membrane tube is 100 μm-1mm, and the thickness of the membrane tube is 100 μm-1mm.

Preferably, the hollow fiber membrane includes polypropylene fiber membrane, polytetrafluoroethylene fiber membrane or polyvinyl chloride hollow fiber membrane.

Preferably, the electrochemical reactor and the ammonia recovery device work in series to achieve selective electrochemical conversion of nitrogen oxides into ammonia and simultaneous recovery of ammonia; the anolyte chamber and the catholyte chamber are both made of insulating materials, and are The electrodes and the anion exchange membrane are closely fitted to ensure that the sealing effect of the device is leak-free; the automatic electrolyte liquid inlet system and the air inlet system are composed of a booster controller and a flow controller to stably control the entry and discharge of waste gas and electrolyte. flow rate.

The second aspect of the present invention discloses a method of using a device for recycling nitrogen oxide waste gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology as described in any one of the above, in the gas diffusion cathode and gas diffusion of the electrochemical reactor A voltage is applied between the anodes, and the flue gas entering from the air intake system is electrochemically reduced to form ammonia. The ammonia flows into the hollow fiber membrane of the ammonia recovery device with the electrolyte in the catholyte chamber, and flows out of the ammonia recovery device through the hollow fiber membrane along with the absorption liquid. , the remaining electrolyte flows back to the catholyte chamber.

Preferably, the voltage is a DC voltage of 0.5-36V; the flow rate of the flue gas is 0.001-10m/s; the flow rate of the electrolyte is 1-500mL/min; the flow rate of the absorption liquid is 1-500mL/min.

The third aspect of the present invention discloses the application of a device for recycling nitrogen oxide exhaust gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology as described in any one of the above in the treatment of nitrogen oxide exhaust gas.

Compared with the prior art, the present invention has the following beneficial effects:

1. The technical solution of the present invention, because the cathode adopts a porous gas diffusion electrode loaded with metal single atoms or nanoclusters, can selectively reduce nitrogen oxides to ammonia at the gas-liquid-solid three-phase interface, and ammonia enters with the catholyte. The hollow fiber membrane module in the ammonia recovery device then uses the ammonia evaporation pressure difference on both sides of the hollow fiber membrane to achieve efficient separation of ammonia in the electrolyte. Finally, the ammonia is absorbed by the acid liquid in the ammonia recovery device. Therefore, the device of the present invention that uses electrochemical reduction technology coupled with gas-liquid separation membrane technology to resource-process nitrogen oxide waste gas can realize the selective conversion of nitrogen oxides into ammonia and the simultaneous recovery of ammonia, which is beneficial to the control and control of nitrogen oxide pollutants. Resource utilization. Moreover, foam titanium-based metal single atom or nanocluster electrodes have higher activity and better stability, which helps to improve the selectivity of converting nitrogen oxide pollutants into ammonia. Moreover, the hydrophobic hollow fiber membrane has high ammonia recovery selectivity, which helps to increase the ammonia recovery rate.

2. The device provided by the present invention can effectively reduce the energy consumption of processing nitrogen oxides in industrial flue gas, and has high electrode performance. It can efficiently and highly selectively convert nitrogen oxides into ammonia and efficiently recover the proceeds from the selective conversion of nitrogen oxides. Ammonia is of great significance for today's environmental protection and waste gas resource utilization, and also has great market application prospects.

3. The present invention uses electrochemical reduction technology to selectively convert nitrogen oxides into ammonia at the three-phase interface of the gas diffusion cathode. Then the ammonia is pumped into the ammonia recovery device with the catholyte and passes through the hollow fiber membrane to be recovered by the absorption liquid. The device in the present invention is used to treat waste gas containing nitrogen oxides, which not only has low energy consumption, but also has high electrode activity and selectivity, high nitrogen oxide resource treatment efficiency, no secondary pollution, and is suitable for industrial promotion.

Description of the drawings

Figure 1 is a schematic structural diagram of the device of the present invention;

Figure 2 is a physical diagram of a titanium foam gas diffusion electrode loaded with copper single atoms;

Figure 3 is an AC-TEM image of a titanium foam gas diffusion electrode loaded with copper single atoms;

Figure 4 shows the ammonia selectivity and ammonia production rate of the titanium foam gas diffusion electrode loaded with copper single atoms in the treatment of simulated flue gas containing nitrogen oxides;

Figure 5 is a diagram of ammonia recovery selectivity and efficiency of the device of the present invention;

Figure 6 is a diagram of the ammonia selectivity and ammonia production rate of the device of the present invention for processing simulated flue gas containing different nitrogen oxide concentrations;

Figure 7 is a diagram of the ammonia selectivity and ammonia production rate of the device of the present invention for processing simulated flue gas containing 5% sulfur dioxide and 20% nitrogen oxides;

Figure 8 is a diagram showing the ammonia recovery selectivity and efficiency of the device of the present invention for processing simulated flue gas containing 5% sulfur dioxide and 20% nitrogen oxides;

In the picture: 1-cathode gas chamber; 2-gas diffusion cathode; 3-cathode liquid chamber; 4-anion exchange membrane; 5-gas diffusion anode; 6-anolyte liquid chamber; 7-ammonia recovery device; 8-transport equipment.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

In addition, the technical solutions in various embodiments can be combined with each other, but it must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that such a combination of technical solutions does not exist. , nor within the protection scope required by the present invention.

On the one hand, the present invention provides a device for recycling nitrogen oxide waste gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology, which is used for the selective conversion of nitrogen oxide pollutants into ammonia and the simultaneous recovery of ammonia to achieve nitrogen oxidation. Resource utilization of chemical pollutants.

Please refer to Figure 1. In an example of a device for recycling nitrogen oxide waste gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology according to the present invention, a series device for selective conversion of nitrogen oxide pollutants into ammonia and simultaneous recovery of ammonia includes Electrochemical reactor and ammonia recovery device 7. The electrochemical reactor includes a power supply, a cathode gas chamber 1, a gas diffusion cathode 2, a catholyte chamber 3, an anion exchange membrane 4, a gas diffusion anode 5 and an anolyte chamber 6. The gas diffusion cathode 2 is a porous titanium foam electrode loaded with active material. The anion exchange membrane 4 is located between the catholyte chamber 3 and the gas diffusion anode 5. The gas diffusion anode 5 is a ruthenium-iridium coated titanium electrode, and the ammonia recovery device 7 is a hollow fiber membrane module. .

In the present invention, the power supply adopts a DC power supply, and a titanium foam gas diffusion electrode loaded with metal single atoms or nanoclusters is used as the gas diffusion cathode 2, a ruthenium-iridium coated electrode is used as the gas diffusion anode 5, the catholyte chamber 3 and the gas diffusion anode 5 Anion exchange membrane 4 is placed between them, and the multi-layer materials of cathode gas chamber 1, gas diffusion cathode 2, catholyte chamber 3, anion exchange membrane 4, gas diffusion anode 5 and anolyte chamber 6 are clamped, and the cathode gas chamber 1 and There is a gas flow channel between the gas diffusion cathode 2, and an electrolyte channel between the gas diffusion anode 5 and the anolyte chamber 6. At the same time, the gas diffusion cathode 2 and the gas diffusion anode 5 are connected to the negative electrode and the positive electrode of the DC power supply respectively through wires. The hollow fiber membrane module is used as the ammonia recovery device 7, and the catholyte chamber 3 and the ammonia recovery device 7 are connected in series through pipelines. The gas diffusion cathode 2 in the present invention adopts a porous gas diffusion electrode loaded with metal single atoms or nanoclusters, which can selectively reduce nitrogen oxides to ammonia at the gas-liquid-solid three-phase interface. The ammonia recovery device 7 adopts a hollow fiber hydrophobic membrane and uses acid liquid as the absorbing liquid, which can efficiently separate and recover ammonia that enters the hollow fiber membrane module with the catholyte.

Therefore, it can be understood that the technical solution of the present invention, because the gas diffusion cathode 2 adopts a porous gas diffusion electrode loaded with metal single atoms or nanoclusters, can selectively reduce nitrogen oxides to ammonia at the gas-liquid-solid three-phase interface. , ammonia enters the hollow fiber membrane module in the ammonia recovery device 7 with the catholyte, and then uses the ammonia evaporation pressure difference on both sides of the hollow fiber membrane to achieve efficient separation of ammonia in the electrolyte, and finally the ammonia is absorbed by the acid liquid in the ammonia recovery device 7 absorb. Therefore, the device of the present invention for selectively reducing nitrogen oxides to ammonia coupled with ammonia recovery can realize selective conversion of nitrogen oxides to ammonia and simultaneous recovery of ammonia, which is beneficial to the control and resource utilization of nitrogen oxide pollutants. Moreover, foam titanium-based metal single atom or nanocluster electrodes have higher activity and better stability, which helps to improve the selectivity of converting nitrogen oxide pollutants into ammonia. Moreover, the hydrophobic hollow fiber membrane has high ammonia recovery selectivity, which helps to increase the ammonia recovery rate.

It should be noted that the device for recycling nitrogen oxide exhaust gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology also includes transportation equipment 8 and transportation pipelines (including transportation pipelines for transporting flue gas, transport pipelines for transporting electrolyte, transport and absorption liquid transportation pipeline and the transportation pipeline connecting the ammonia recovery device 7 and the cathode liquid chamber 3), the transportation pipeline is connected to the cathode gas chamber 1 (air inlet system), and the transportation pipeline is connected to the anolyte liquid chamber 6 (electrolyte liquid inlet system) ), the transport pipeline connects the catholyte chamber 3 and the ammonia recovery device 7, and the transport pipelines are equipped with transport equipment 8. The transport equipment 8 can be selected as a fan, air pump, or water pump according to the passing fluid.

Optionally, the active components of the gas diffusion cathode 2 to achieve selective reduction of nitrogen oxides to ammonia are single atoms of manganese, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, and gold. , at least one type of nanocluster. Manganese, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold single atoms, and nanoclusters can all be used as gas diffusion cathodes 2 to achieve selective reduction of nitrogen oxides to ammonia. Active ingredients, one or more combinations thereof can be selected during use.

Optionally, the hollow fiber membrane of the ammonia recovery device 7 is a type of hydrophobic porous membrane such as polypropylene fiber membrane, polytetrafluoroethylene fiber membrane, polyvinyl chloride hollow fiber membrane, etc. When assembling the ammonia recovery device 7, one of these substances can be used as the hydrophobic porous membrane.

Optionally, the loading amount of the active material of the gas diffusion cathode 2 ranges from 0.01% to 20%. For example, the loading of active substance is 0.01%, 0.1%, 1%, 5%, 10% or 20%. Preferably, the loading is 0.1%-1%, such as 0.1%, 0.2%, 0.4%, 0.8% or 1%.

Another aspect of the present invention provides an application of a device in treating industrial flue gas containing nitrogen oxides.

The device provided by the invention can effectively reduce the energy consumption for processing nitrogen oxides in industrial flue gas, and has high electrode performance. It can efficiently and highly selectively convert nitrogen oxides into ammonia and efficiently recover ammonia obtained by selective conversion of nitrogen oxides. It is of great significance for today's environmental protection and waste gas resource utilization, and also has great market application prospects.

The present invention also provides a method for using electrochemical reduction technology coupled with gas-liquid separation membrane technology to resource-process nitrogen oxide waste gas, which is applied to the above-mentioned electrochemical reduction technology coupled with gas-liquid separation membrane technology to resource-process nitrogen. The device for oxide waste gas includes the following steps:

The flue gas containing nitrogen oxide pollutants is passed into the cathode gas chamber 1, the electrolyte is passed into the catholyte chamber 3 and the anolyte chamber 6, the absorption liquid is passed into the ammonia recovery device 7, and the gas diffusion anode is A DC voltage of 0.5V-36V is applied between 5 and the gas diffusion cathode 2. The control flue gas flow rate range is 0.001m/s-10m/s, and the electrolyte and absorption liquid flow rate range is 1mL/min-500mL/min.

Here, the DC voltage range is preferably 2V-5V, for example, the applied voltage is 2V, 3V, 4V or 5V. By adjusting the DC voltage and gas flow, nitrogen oxide pollutants are highly selectively reduced to ammonia.

Here, the flow rate range of the catholyte and absorption liquid is preferably 50-250 mL/min, for example, the flow rate used is 50 mL/min, 100 mL/min, 150 mL/min, 200 mL/min or 250 mL/min. By adjusting the flow rates of the catholyte and absorbing liquid, the ammonia converted by the gas diffusion cathode 2 of the electrochemical reactor can be efficiently recovered in the ammonia recovery device 7 .

The method and device for recycling nitrogen oxide exhaust gas according to the present invention will be described in detail below through specific examples.

Example 1

(1) Preparation of gas diffusion cathode 2: Dissolve 20mg copper chloride in 5mL ethanol, and then spray the copper chloride ethanol solution onto the surface of porous titanium foam of 2cm (length) * 2cm (width) * 0.68cm (thickness) , and finally calcined at 400°C in H ₂ /Ar atmosphere to obtain copper single-atom foam titanium gas diffusion cathode 2. See Figures 2 and 3 for the physical picture and AC-TEM image of the copper single-atom gas diffusion cathode 2.

(2) Assembly of the electrochemical reactor and ammonia recovery series device: use the electrode prepared in step (1) as the gas diffusion cathode 2, use the iridium-ruthenium coated electrode as the gas diffusion anode 5, and then use the cathode gas chamber 1 and the gas diffusion anode 5. The cathode 2, catholyte chamber 3, anion exchange membrane 4, gas diffusion anode 5 and anolyte chamber 6 are clamped. There is an air flow channel between the cathode gas chamber 1 and the gas diffusion cathode 2. The anolyte chamber 6 and the gas diffusion anode are There is an electrolyte channel between 5, and at the same time, the gas diffusion cathode 2 and the gas diffusion anode 5 are respectively connected to the negative electrode and the positive electrode of the DC power supply through wires to obtain an electrochemical reactor. The electrochemical reactor and the ammonia recovery device in series can be obtained by connecting the ammonia recovery device 7 based on the hollow fiber membrane module with the catholyte chamber 3 of the electrochemical reactor using a transportation pipeline.

(3) A method for treating nitrogen oxide pollutants using an electrochemical reactor and an ammonia recovery series device in step (2), including the following steps: passing gas containing nitrogen oxides into the cathode gas chamber 1, and the concentration of nitrogen oxides is 20%, using Ar gas as the balance gas, and the total flow rate is controlled at 100 mL/min. The 0.5 mol/L potassium sulfate electrolyte is continuously passed into the catholyte chamber 3 and the anolyte chamber 6 through the conveying equipment 8 (water pump), with a flow rate of 100 mL/min. Then apply a DC voltage between the gas diffusion cathode 2 and the gas diffusion anode 5, and detect the ammonia concentration in the electrolyte in the catholyte chamber 3 and the absorption liquid of the ammonia recovery device 7. See Figure 4 for the catalytic performance, and see Figure 5 for the recovery efficiency and selectivity. .

As can be seen from Figure 4, in the voltage range of 2-3V, the Faradaic efficiency of selective reduction of nitrogen oxides to ammonia is above 90%. As the voltage increases, the ammonia production rate gradually increases, up to 1200mmol/h. /cm, the catalytic efficiency of converting nitrogen oxides into ammonia is relatively high. It can be seen from Figure 5 that within 50 hours of continuous operation, the ammonia recovery efficiency of the series device is above 90%, and the selectivity is close to 100%. The efficiency and selectivity of ammonia recovery in series units are high.

Example 2

The ability of the device to process simulated flue gas containing different concentrations of nitrogen oxides: Use the series device assembled in Example 1 to pass nitrogen oxides containing 0%, 1%, 5%, 10%, and 20% into the cathode gas chamber to Ar gas was used as a balance gas, and the total flow rate was controlled at 100 mL/min. 0.5mol/L potassium sulfate electrolyte was continuously passed into the catholyte chamber and anolyte chamber through a water pump, with a flow rate of 100mL/min. Then apply a DC voltage of 3V between the cathode and anode, and detect the ammonia concentration in the electrolyte in the catholyte chamber and the absorption solution of the ammonia recovery device. See Figure 6 for the catalytic performance.

It can be seen from Figure 6 that as the concentration of nitrogen oxides in the simulated flue gas increases, the Faradaic efficiency of the selective reduction of nitrogen oxides to ammonia at the electrode is above 90%, the ammonia production rate gradually increases, and the device oxidizes nitrogen at different concentrations. The material processing capacity is higher.

Example 3

Anti-interference ability test of the device: Using the series device assembled in Example 1, the cathode gas chamber containing 5% sulfur dioxide and 20% nitrogen oxide was passed into the cathode gas chamber, with Ar gas as the balance gas, and the total flow rate was controlled at 100 mL/min. 0.5mol/L potassium sulfate electrolyte was continuously passed into the catholyte chamber and anolyte chamber through a water pump, with a flow rate of 100mL/min. Then apply a DC voltage between the cathode and the anode, and detect the ammonia concentration in the electrolyte in the catholyte chamber and the absorption fluid of the ammonia recovery device. See Figure 7 for the catalytic performance, and Figure 8 for the recovery efficiency and selectivity.

It can be seen from Figures 7 and 8 that in the voltage range of 2-3V, the impact of the presence of sulfur dioxide in the simulated flue gas on the Faradaic efficiency and ammonia production rate of the device for selectively converting nitrogen oxides into ammonia, as well as the ammonia recovery efficiency and selectivity of the device Not big, the anti-interference ability of the device is good.

The above description of the embodiments is to facilitate those of ordinary skill in the technical field to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without inventive efforts. Therefore, the present invention is not limited to the above embodiments. Based on the disclosure of the present invention, improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims (10)

1. A device for recycling nitrogen oxide waste gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology, which is characterized by comprising a cathode gas chamber (1), a gas diffusion cathode (2), and a catholyte chamber (3) , anion exchange membrane (4), gas diffusion anode (5) and anolyte chamber (6) are laminated in sequence to form an electrochemical reactor and an ammonia recovery device (7) connected to the catholyte chamber (3) through a transportation pipeline ); The electrochemical reactor also includes an air inlet system connected to the cathode gas chamber (1), an electrolyte liquid inlet system connected to the anolyte chamber (6), and a gas diffusion cathode (2) and a gas diffusion system respectively. The power supply connected to the anode (5); the gas diffusion cathode (2) is based on titanium foam, and the surface is loaded with transition metal single atoms or nanocluster active materials to selectively reduce nitrogen oxides to ammonia; The electrochemical reactor and the ammonia recovery device (7) are arranged in series with each other; the ammonia recovery device (7) is equipped with a hollow fiber membrane, and one side of the hollow fiber membrane passes through the catholyte chamber (3) The input electrolyte passes through the absorption liquid on the other side; The electrochemical reactor converts nitrogen oxides in the flue gas into ammonia. The ammonia is input into the ammonia recovery device (7) along with the electrolyte in the catholyte chamber (3) through the transportation pipeline, and enters the absorption device through the hollow fiber membrane. The liquid leaves the ammonia recovery device (7) with the absorption liquid, and the remaining electrolyte is returned to the catholyte chamber (3). 2. A device for recycling nitrogen oxide waste gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology according to claim 1, characterized in that the pore size of the gas diffusion cathode (2) is 50-100 μm. . 3. A device for recycling nitrogen oxide waste gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology according to claim 2, characterized in that the transition metal single atom or nanocluster active material includes manganese , one or more of iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum and gold, with a mass loading of 0.01-20%. 4. A device for recycling nitrogen oxide waste gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology according to claim 1, characterized in that the electrolyte is sodium hydroxide, potassium hydroxide, sulfuric acid One or more of sodium and potassium sulfate, with a concentration of 0.1-5mol/L; the absorption liquid is one or more of sulfuric acid, nitric acid and hydrochloric acid, with a concentration of 0.1-5mol/L. 5. A device for recycling nitrogen oxide waste gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology according to claim 1, characterized in that the gas diffusion anode (5) is ruthenium-iridium coated titanium Electrode, coating thickness is 8-15μm. 6. A device for recycling nitrogen oxide waste gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology according to claim 1, characterized in that the hollow fiber membrane is a hydrophobic porous membrane, and the inner diameter of the membrane tube The thickness of the membrane tube is 100μm-1mm. 7. A device for recycling nitrogen oxide waste gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology according to claim 6, characterized in that the hollow fiber membrane includes polypropylene fiber membrane, polytetrafluoroethylene Vinyl fiber membrane or polyvinyl chloride hollow fiber membrane. 8. A method of using the electrochemical reduction technology coupled with the gas-liquid separation membrane technology as claimed in any one of claims 1 to 7 for recycling nitrogen oxide waste gas, characterized in that the gas diffusion in the electrochemical reactor A voltage is applied between the cathode (2) and the gas diffusion anode (5), and the flue gas entering from the air intake system is electrochemically reduced to form ammonia. The ammonia flows into the ammonia recovery device (7) along with the electrolyte in the catholyte chamber (3). The hollow fiber membrane passes through the hollow fiber membrane and flows out of the ammonia recovery device (7) with the absorption liquid, and the remaining electrolyte flows back to the catholyte chamber (3). 9. A method of using a device for recycling nitrogen oxide exhaust gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology according to claim 8, characterized in that the voltage is a DC voltage of 0.5-36V; The flow rate of the flue gas is 0.001-10m/s; the flow rate of the electrolyte is 1-500mL/min; the flow rate of the absorption liquid is 1-500mL/min. 10. The application of a device for recycling nitrogen oxide exhaust gas using electrochemical reduction technology coupled with gas-liquid separation membrane technology as described in any one of claims 1 to 7 in the treatment of nitrogen oxide exhaust gas.