Method for preparing N2O through catalysis of DBD cooperating with ZrO2 and application of N2O

Abstract

The invention discloses a method for preparing N2O through DBD and ZrO2 catalysis, and belongs to the technical field of plasma catalysis. Comprising the following steps: uniformly filling zirconium dioxide balls into a discharge area of a hollow quartz tube by adopting a plasma reactor; introducing reaction gases NO, N2 and O2 into the discharge area; circulating cooling water is introduced into the hollow grounding electrode in the hollow quartz tube; an input power supply is connected to the discharge area to start discharging, and N2O is obtained after reaction. Compared with a traditional process, the method has the advantages that the energy consumption can be obviously reduced by more than 50%, and meanwhile, a complicated external heating and heat preservation system is omitted. Through the mutual synergistic effect of ZrO2, high-energy electrons and active free radicals, high-selectivity generation of N2O can be achieved, energy consumption is greatly reduced through normal-temperature operation, high-temperature risks are avoided, the reaction rate is high, starting and stopping can be fast, potential out-of-control hidden dangers are avoided, and the safety coefficient is greatly increased.

Description

Technical Field

[0001] This invention relates to the field of plasma catalysis technology, specifically to a method for preparing N2O by DBD synergistic ZrO2 catalysis and its application. Background Technology

[0002] Nitrogen sulfide (N2O), commonly known as laughing gas, is widely used in the medical field as a safe and effective inhaled analgesic / sedative (especially for short-term procedures in dentistry, obstetrics, and pediatrics), and as an ideal food-grade propellant for whipping butter. It also has auxiliary applications in specific industrial fields (such as rocket propulsion testing and semiconductor manufacturing). With the rapid development of my country's industries and technological advancements, the demand for N2O is continuously increasing. Therefore, developing a highly efficient, rapid-start / stop, and highly selective preparation method is urgently needed.

[0003] Currently, the ammonium nitrate thermal decomposition method, as the mainstream industrial route, faces significant energy consumption and safety challenges. This method operates at high temperatures, where ammonium nitrate is prone to violent decomposition, resulting in a high risk of side reactions (such as nitrogen generation). The ammonia catalytic oxidation method relies on precious metal catalyst systems such as platinum and rhodium. These catalysts are not only expensive but also susceptible to poisoning and deactivation in sulfur-containing environments. Furthermore, this process requires operation in a high-temperature range of 900-1000℃, leading to enormous energy consumption and poor overall economic efficiency, hindering large-scale application.

[0004] DBD (Dielectric Barrier Discharge) plasma technology utilizes high-energy electrons to directly excite reaction molecules, enabling the reaction to proceed efficiently under mild temperature conditions (30-130℃).

[0005] Therefore, how to develop a method for preparing N2O by combining DBD plasma technology with ZrO2 catalysis, which is low in energy consumption, safe, and has a fast reaction rate, and its application, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a method for preparing N2O by DBD synergistic ZrO2 catalysis and its application.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing N2O by DBD synergistic ZrO2 catalysis includes the following steps:

[0009] (1) A plasma reactor is used to uniformly fill the discharge area of ​​the hollow quartz tube with zirconium dioxide spheres;

[0010] (2) Introduce the reaction gases NO, N2 and O2 into the discharge region;

[0011] (3) Connect the hollow grounding electrode inside the hollow quartz tube to the cooling circulating water;

[0012] (4) The discharge area is connected to the input power supply to start discharging, and N2O is obtained after the reaction.

[0013] Furthermore, in step (1), the ratio of the length of the discharge region to the total length of the hollow quartz tube is (1-2):5.

[0014] Furthermore, in step (1), the outer diameter of ZrO2 is 2mm-5mm.

[0015] Furthermore, in step (2), the concentration of NO in the reaction gas is 500 ppm, N2 is used as the balance gas, the volume fraction of O2 is 5%, and the total flow rate of the reaction gas is 100 mL / min.

[0016] Furthermore, in step (3), the temperature of the cooling circulating water is below 30°C.

[0017] Furthermore, in step (4), the voltage of the input power supply is 10kV-20kV, and the frequency of the input power supply is 10kHz-20kHz.

[0018] The present invention also provides an application of the DBD-coordinated ZrO2 catalytic method for N2O preparation in flue gas denitrification.

[0019] The beneficial effects of this invention are:

[0020] This invention addresses the significant energy consumption and safety challenges posed by the thermal decomposition of ammonium nitrate. Under high-temperature conditions, ammonium nitrate is prone to violent decomposition, with a high risk of side reactions (such as nitrogen generation) and potential runaway hazards. The ammonia catalytic oxidation method relies on precious metal catalyst systems, which are not only costly but also susceptible to poisoning and deactivation in sulfur-containing environments. This process requires operation in a high-temperature range of 900-1000℃, resulting in enormous energy consumption, poor overall economic efficiency, and difficulty in large-scale application.

[0021] This invention proposes a method for preparing N2O by DBD synergistic ZrO2 catalysis. Plasma technology utilizes high-energy electrons to directly excite reaction molecules, enabling the reaction to proceed efficiently under mild temperature conditions. The plasma catalysis process operates at near room temperature, effectively eliminating the risk of thermally induced runaway and possessing higher intrinsic safety.

[0022] Compared to traditional processes, the energy consumption of this invention can be significantly reduced by more than 50%, while eliminating the need for complex external heating and insulation systems. Through the synergistic effect of ZrO2, high-energy electrons, and active free radicals, highly selective N2O generation can be achieved. Room temperature operation significantly reduces energy consumption, avoids high-temperature risks, and features a fast reaction rate with rapid start-up and shutdown, avoiding potential runaway hazards and greatly improving safety. This invention uses zirconium dioxide instead of traditional catalysts, avoiding secondary pollution associated with catalyst use; combined with green electricity, it can utilize excess energy and turn waste into treasure to produce high-value-added N2O. It solves the problems of explosive decomposition of ammonium nitrate at high temperatures in traditional ammonium nitrate thermal decomposition methods and the dependence on high-temperature environments and catalyst poisoning in ammonia oxidation methods (>900℃). Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the DBD-synergistic ZrO2 catalytic method for preparing N2O according to Embodiments 1-3 of the present invention; wherein: 1-inlet pipe, 2-flow meter, 3-ball valve, 4-three-way connector inlet, 5-water inlet, 6-low temperature plasma power supply, 7-three-way connector, 8-high voltage electrode, 9-zirconia ball, 10-hollow quartz tube, 11-water outlet, 12-three-way connector outlet, 13-hollow grounding electrode, 14-Fourier transform infrared spectrometer, 15-water pump and water tank.

[0024] Figure 2 This is a graph showing the N2O production of Embodiment 1 of the present invention.

[0025] Figure 3 This is a graph showing the N2O production in Embodiment 2 of the present invention.

[0026] Figure 4 This is a graph showing the N2O production in Embodiment 3 of the present invention.

[0027] Figure 5 This is a graph showing the N2O production of Embodiment 3 of the present invention and Comparative Examples 1-2.

[0028] Figure 6 A physical diagram showing the assembly of a tee connector, a hollow quartz tube, and a hollow grounding electrode. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] The method for preparing N2O by DBD in synergistic ZrO2 catalysis includes the following steps:

[0032] (1) A plasma reactor is used to uniformly fill the discharge area of ​​the hollow quartz tube 10 with zirconium dioxide spheres 9. The ratio of the length of the discharge area to the total length of the hollow quartz tube 10 is 1:5, and the outer diameter of ZrO2 is 2mm.

[0033] (2) The reaction gases NO, N2 and O2 are introduced into the discharge area. The concentration of NO in the reaction gases is 500 ppm, N2 is used as the balance gas, the volume fraction of O2 is 5%, and the total flow rate of the reaction gases is 100 mL / min.

[0034] (3) Connect the hollow grounding electrode 13 inside the hollow quartz tube 10 to the cooling circulating water. The temperature of the cooling circulating water is 25℃.

[0035] (4) The discharge region is connected to the input power supply to begin discharging. The input power supply voltage is 14kV and the input power supply frequency is 15kHz. N2O is obtained after the reaction. The gas after the reaction is passed into a Fourier transform infrared spectrometer 14 to detect the gas composition. The test results are shown in […]. Figure 2 .

[0036] Example 2

[0037] The method for preparing N2O by DBD in synergistic ZrO2 catalysis includes the following steps:

[0038] (1) A plasma reactor is used to uniformly fill the discharge area of ​​the hollow quartz tube 10 with zirconium dioxide spheres 9. The ratio of the length of the discharge area to the total length of the hollow quartz tube 10 is 1:5, and the outer diameter of ZrO2 is 2mm.

[0039] (2) The reaction gases NO, N2 and O2 are introduced into the discharge area. The concentration of NO in the reaction gases is 500 ppm, N2 is used as the balance gas, the volume fraction of O2 is 5%, and the total flow rate of the reaction gases is 100 mL / min.

[0040] (3) Connect the hollow grounding electrode 13 inside the hollow quartz tube 10 to the cooling circulating water. The temperature of the cooling circulating water is below 30°C.

[0041] (4) The discharge region is connected to the input power supply to begin discharging. The input power supply voltage is 16kV and the input power supply frequency is 15kHz. N2O is obtained after the reaction. The gas after the reaction is passed into a Fourier transform infrared spectrometer 14 to detect the gas composition. The test results are shown in […]. Figure 3 .

[0042] Example 3

[0043] The method for preparing N2O by DBD in synergistic ZrO2 catalysis includes the following steps:

[0044] (1) A plasma reactor is used to uniformly fill the discharge area of ​​the hollow quartz tube 10 with zirconium dioxide spheres 9. The ratio of the length of the discharge area to the total length of the hollow quartz tube 10 is 1:5, and the outer diameter of ZrO2 is 2mm-5mm.

[0045] (2) The reaction gases NO, N2 and O2 are introduced into the discharge area. The concentration of NO in the reaction gases is 500 ppm, N2 is used as the balance gas, the volume fraction of O2 is 5%, and the total flow rate of the reaction gases is 100 mL / min.

[0046] (3) Connect the hollow grounding electrode 13 inside the hollow quartz tube 10 to the cooling circulating water. The temperature of the cooling circulating water is below 30°C.

[0047] (4) The discharge region is connected to the input power supply to begin discharging. The input power supply voltage is 18kV and the input power supply frequency is 15kHz. N2O is obtained after the reaction. The gas after the reaction is passed into a Fourier transform infrared spectrometer 14 to detect the gas composition. The test results are shown in […]. Figure 4 .

[0048] Comparative Example 1

[0049] The method for preparing N2O by DBD in synergistic ZrO2 catalysis includes the following steps:

[0050] (1) A plasma reactor is used to uniformly fill the discharge area of ​​the hollow quartz tube 10 with zirconium dioxide spheres 9. The ratio of the length of the discharge area to the total length of the hollow quartz tube 10 is 1:5, and the outer diameter of the glass spheres is 2 mm.

[0051] (2) The reaction gases NO, N2 and O2 are introduced into the discharge area. The concentration of NO in the reaction gases is 500 ppm, N2 is used as the balance gas, the volume fraction of O2 is 5%, and the total flow rate of the reaction gases is 100 mL / min.

[0052] (3) Connect the hollow grounding electrode 13 inside the hollow quartz tube 10 to the cooling circulating water. The temperature of the cooling circulating water is below 30°C.

[0053] (4) The discharge region is connected to the input power supply to begin discharging. The input power supply voltage is 18kV and the input power supply frequency is 15kHz. N2O is obtained after the reaction. The gas after the reaction is passed into a Fourier transform infrared spectrometer 14 to detect the gas composition. The test results are shown in […]. Figure 5 .

[0054] Comparative Example 2

[0055] The method for preparing N2O by DBD in synergistic ZrO2 catalysis includes the following steps:

[0056] (1) A plasma reactor is used to uniformly fill the discharge area of ​​the hollow quartz tube 10 with zirconium dioxide spheres 9. The ratio of the length of the discharge area to the total length of the hollow quartz tube 10 is 1:5. The outer diameter of aluminum oxide is 2mm-5mm.

[0057] (2) The reaction gases NO, N2 and O2 are introduced into the discharge area. The concentration of NO in the reaction gases is 500 ppm, N2 is used as the balance gas, the volume fraction of O2 is 5%, and the total flow rate of the reaction gases is 100 mL / min.

[0058] (3) Connect the hollow grounding electrode 13 inside the hollow quartz tube 10 to the cooling circulating water. The temperature of the cooling circulating water is below 30°C.

[0059] (4) The discharge region is connected to the input power supply to begin discharging. The input power supply voltage is 18kV and the input power supply frequency is 15kHz. N2O is obtained after the reaction. The gas after the reaction is passed into a Fourier transform infrared spectrometer 14 to detect the gas composition. The test results are shown in […]. Figure 5 .

[0060] like Figure 1 As shown, the plasma reactor includes: an inlet pipe 1, a flow meter 2, a ball valve 3, a low-temperature plasma power supply 6, a three-way connector 7, a hollow quartz tube 10, a hollow grounding electrode 13, a Fourier transform infrared spectrometer 14, and a water pump and tank 15. The inlet 4 of the three-way connector 7 connected to the top of the inlet pipe 1, flow meter 2, ball valve 3, and hollow quartz tube 10 is sequentially connected to the interior of the hollow quartz tube 10 via a pipeline. The outlet 12 of the three-way connector 7 connected to the bottom of the hollow quartz tube 10 is connected to the Fourier transform infrared spectrometer 14 via a pipeline. The water pump and tank 15 are connected to the top inlet 5 of the stainless steel hollow grounding electrode 13 via a pipeline. The hollow grounding electrode 13 is fixedly connected to one end of the three-way connector 7, and the hollow quartz tube 10 is fixedly connected to the other end of the three-way connector 7. The bottom outlet 11 of the grounding electrode 13 is connected to the water pump tank 15 via a pipeline and connected to the cooling circulating water, so that water can flow in through the inlet 5 and out through the outlet 11, thereby reducing the temperature of the hollow quartz tube 10. Zirconia balls 9 are uniformly filled into the discharge area of ​​the hollow quartz tube 10. The reaction gases NO, N2 and O2 are introduced into the discharge area through the gas inlet pipe 1. The high-voltage electrode 8 is an iron mesh covering the surface of the hollow quartz tube 10 in the discharge area and connected to the hollow quartz tube 10 with copper wire. The high-voltage electrode 8 enables the quartz tube reactor to discharge. The discharge area is connected to the input power supply low-temperature plasma power supply 6 to start the discharge. After the reaction, N2O is obtained. The gas after the reaction is introduced into the Fourier transform infrared spectrometer 14 through the gas outlet 12 of the bottom three-way connector of the hollow quartz tube 10 to detect the gas composition.

[0061] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for the catalytic production of N20 by DBD in cooperation with Zr02, characterized in that, The method comprises the following steps: (1) uniformly filling ZrO2 balls into the discharge area of a hollow quartz tube by using a plasma reactor; (2) introducing reaction gases NO, N2 and O2 into the discharge area; (3) connecting cooling circulating water into the hollow ground electrode in the hollow quartz tube; (4) connecting an input power source to the discharge area to start discharging, and obtaining N2O after the reaction.

2. The method for preparing N20 by DBD cooperating with Zr02catalysis according to claim 1, characterized in that, In step (1), the ratio of the length of the discharge area to the total length of the hollow quartz tube is 1-2:

5. 3.The method of claim 1, wherein the DBD cooperates with ZrO 2 to catalytically produce N 2 O. In step (1), the outer diameter of ZrO2 is 2-5 mm. 4.The method of claim 1, wherein the DBD cooperates with ZrO 2 to catalytically produce N 2 O. In step (2), the concentration of NO in the reaction gas is 500 ppm, N2 is used as the balance gas, the volume fraction of O2 is 5%, and the total flow rate of the reaction gas is 100 mL / min. 5.The method of claim 1, wherein the DBD cooperates with ZrO 2 to catalytically produce N 2 O. In step (3), the water temperature of the cooling circulating water is below 30℃. 6.The method of claim 1, wherein the DBD cooperates with ZrO 2 to catalytically produce N 2 O. In step (4), the voltage of the input power source is 10-20 kV, and the frequency of the input power source is 10-20 kHz.

7. Application of the method for preparing N2O by DBD and ZrO2 catalysis according to any one of claims 1-6 in flue gas denitration.

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