Preparation device and preparation method of high-purity nitrogen

Abstract

The invention relates to the technical field of high-purity nitrogen preparation, in particular to a high-purity nitrogen preparation device and a preparation method thereof.The high-purity nitrogen preparation device comprises a gas purification device; the gas purification device comprises a heat exchanger, a catalytic oxidation reactor, a precision filter and a first drying adsorption tower or / and a second drying adsorption tower, a first outlet of the heat exchanger is connected with an inlet of the catalytic oxidation reactor, and an outlet of the catalytic oxidation reactor is connected with an inlet of the heat exchanger; a second outlet of the heat exchanger is respectively connected with bottom inlets of the first drying adsorption tower or / and the second drying adsorption tower, and top outlets of the first drying adsorption tower or / and the second drying adsorption tower are connected with an inlet of the precision filter. The preparation device is simple in structure and easy to operate, the purity of the high-purity nitrogen prepared by the preparation device is greater than or equal to 99.9996%, O2 is less than or equal to 0.5 ppm, H2 is less than or equal to 0.5 ppm, CO2 is less than or equal to 0.5 ppm, CH4 is less than or equal to 0.5 ppm, H2O is less than or equal to 2 ppm, and 0.03 mu m is less than or equal to dust particle lt; the thickness is 0.2 mu m, which is higher than the national standard.

Description

Technical Field

[0001] The invention relates to the technical field of high-purity nitrogen preparation, and in particular to a high-purity nitrogen preparation device and a preparation method thereof. Background Art

[0002] As a gas with stable chemical properties, nitrogen is widely used in electronics, chemical industry, machinery, metallurgy, food and other industries.

[0003] In the aerospace industry, high-purity nitrogen is mainly used for air-tightness inspection of rocket propellant tanks, engine systems, etc. To ensure the normal operation of the turbopump of the rocket engine system, the pump is required to operate under a certain net positive suction pressure head to prevent cavitation. For this reason, the propellant tank must be pressurized before the rocket takes off.

[0004] According to the national standard, high-purity nitrogen requires a hydrogen content of ≤1ppm. Currently, the main method for preparing high-purity nitrogen is air separation. In the process of using this technology to prepare high-purity nitrogen, hydrogen is enriched in the nitrogen and cannot be removed. The hydrogen content exceeds the national standard and cannot meet the index requirements for high-purity nitrogen in the aerospace industry. Summary of the invention

[0005] In view of the above problems, the first object of the present invention is to provide a high-purity nitrogen production device, which has a simple structure and is easy to operate. The purity of the high-purity nitrogen produced by the production device is ≥99.9996%, wherein O2≤0.5ppm, H2≤0.5ppm, CO2≤0.5ppm, CH4≤0.5ppm, H2O≤2ppm, and dust particles of 0.03μm≤<0.2μm, which is higher than the national standard.

[0006] The second object of the present invention is to provide a method for preparing high-purity nitrogen, which is simple and easy to operate, and the high-purity nitrogen prepared by the method has high quality and good stability.

[0007] The first technical solution adopted by the present invention is: a high-purity nitrogen preparation device, including a gas purification device; the gas purification device includes a heat exchanger, a catalytic oxidation reactor, a precision filter, a first drying adsorption tower and / or a second drying adsorption tower,

[0008] The first outlet of the heat exchanger is connected to the inlet of the catalytic oxidation reactor, and the outlet of the catalytic oxidation reactor is connected to the inlet of the heat exchanger; the second outlet of the heat exchanger is respectively connected to the bottom inlet of the first drying adsorption tower and / or the second drying adsorption tower, and the top outlet of the first drying adsorption tower and / or the second drying adsorption tower is connected to the inlet of the precision filter.

[0009] Preferably, the gas purification device further comprises an online detection device, and the online detection device is connected to the outlet of the precision filter.

[0010] Preferably, the online detection device is a trace oxygen analyzer.

[0011] Preferably, the high-purity nitrogen production device further comprises a liquid nitrogen storage and gasification device, a pressure reducer, a pressure booster, a busbar and a high-purity nitrogen storage device;

[0012] The liquid nitrogen storage and gasification device is connected to the heat exchanger of the gas purification device through a pressure reducer; the precision filter of the gas purification device is connected to the inlet of the boosting device, and the outlet of the boosting device is connected to the high-purity nitrogen storage device through a bus.

[0013] Preferably, the high-purity nitrogen production device further comprises a cooling device, and the cooling device is respectively connected to the gas purification device and the pressurizing device; the gas purification device further comprises a cooler;

[0014] The second outlet of the heat exchanger is connected to the inlet of the cooler, the cooler is connected to a cooling device, and the outlet of the cooler is respectively connected to the bottom inlet of the first drying adsorption tower and / or the second drying adsorption tower.

[0015] Preferably, the boosting device is a diaphragm compressor.

[0016] The second technical solution adopted by the present invention is: a method for producing high-purity nitrogen based on the production device described in the first technical solution, comprising the following steps:

[0017] S2: The raw nitrogen is converted into high-purity nitrogen by the gas purification device, specifically comprising:

[0018] The raw nitrogen enters the gas purification device, and first passes through the heat exchanger to preheat the raw nitrogen. The heated raw nitrogen is then input into the catalytic oxidation reactor through the first outlet of the heat exchanger. The catalytic oxidation reactor oxidizes H2, CO, CH4, and total hydrocarbons in the raw nitrogen into H2O and CO2 to achieve preliminary impurity removal.

[0019] The raw nitrogen after preliminary impurity removal comes out from the top of the catalytic oxidation reactor and enters the heat exchanger for preliminary cooling;

[0020] The raw nitrogen after impurities are removed and the temperature is reduced comes out from the second outlet at the bottom of the heat exchanger, and enters the first drying adsorption tower and / or the second drying adsorption tower from the bottom to adsorb H2O and CO2 at room temperature; the raw nitrogen comes out from the top of the first drying adsorption tower and / or the second drying adsorption tower, and enters the precision filter, where dust particles are removed to obtain high-purity nitrogen.

[0021] Preferably, the step S2 further comprises: performing online detection on the high-purity nitrogen by an online detection device.

[0022] Preferably, the step S2 further comprises: the raw nitrogen after preliminary impurity removal comes out from the top of the catalytic oxidation reactor and enters the heat exchanger for preliminary cooling, and then enters the cooler from the second outlet at the bottom of the heat exchanger, and the cold water of the cooling device enters from the bottom of the cooler, and the cold water after absorbing heat returns to the cooling device from the top of the cooler to realize circulating cooling;

[0023] The raw nitrogen after impurity removal and temperature reduction comes out from the top of the cooler, and enters the first drying adsorption tower and / or the second drying adsorption tower from the bottom to adsorb H2O and CO2 at room temperature; the raw nitrogen comes out from the top of the first drying adsorption tower and / or the second drying adsorption tower, and enters the precision filter, where dust particles are removed to obtain high-purity nitrogen.

[0024] Preferably, the high-purity nitrogen production method further comprises S1: gasifying the liquid nitrogen into raw nitrogen by the liquid nitrogen storage and gasification device, and decompressing the raw nitrogen by a pressure reducer;

[0025] S2: converting the raw nitrogen into high-purity nitrogen through the gas purification device;

[0026] S3: The high-purity nitrogen is pressurized by a pressurizing device, and the temperature of the pressurized high-purity nitrogen is reduced to room temperature by a cooling device, and then charged into a high-purity nitrogen storage device.

[0027] Beneficial effects of the above technical solution:

[0028] (1) The high-purity nitrogen production device provided by the present invention has a simple structure and is easy to operate. The raw nitrogen (purity ≥99.99%) can be made into high-purity nitrogen through the gas purification device in the production device. The purity of the high-purity nitrogen is ≥99.9996%, wherein O2≤0.5ppm, H2≤0.5ppm, CO2≤0.5ppm, CH4≤0.5ppm, H2O≤2ppm, and dust particles 0.03μm≤<0.2μm, which is higher than the national standard.

[0029] (2) The method for preparing high-purity nitrogen provided by the present invention is simple and easy to operate, and the high-purity nitrogen prepared by the method is of high quality and good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the structure of a gas purification device 3 in a high-purity nitrogen production device provided by one embodiment of the present invention;

[0031] Figure 2A schematic diagram of the structure of a high-purity nitrogen production device provided by one embodiment of the present invention;

[0032] Among them, 1-liquid nitrogen storage and gasification device; 2-pressure reducer; 3-gas purification device, 31-heat exchanger, 32-catalytic oxidation reactor, 33-cooler, 34-first drying adsorption tower, 35-second drying adsorption tower, 36-precision filter, 37-online detection device; 4-boosting device; 5-bus; 6-high-purity nitrogen storage device; 7-cooling device; F1, F2, F3, F4, F5, F6, F7, F8, F9, F10-solenoid valves; V1, V2, V3, V4, V5-stop valves. DETAILED DESCRIPTION

[0033] The present invention is further described below through specific embodiments. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the principle of the present invention, and these should also be regarded as belonging to the protection scope of the present invention.

[0034] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

[0035] Example 1

[0036] like Figure 1 As shown, the present invention discloses a high-purity nitrogen preparation device, including a gas purification device 3; the gas purification device 3 includes a heat exchanger 31, a catalytic oxidation reactor 32, a precision filter 36, a first drying adsorption tower 34 and / or a second drying adsorption tower 35,

[0037] The first outlet of the heat exchanger 31 is connected to the inlet of the catalytic oxidation reactor 32, and the outlet of the catalytic oxidation reactor 32 is connected to the inlet of the heat exchanger 31; the second outlet of the heat exchanger 31 is respectively connected to the bottom inlet of the first drying adsorption tower 34 and / or the second drying adsorption tower 35, and the top outlet of the first drying adsorption tower 34 and / or the second drying adsorption tower 35 is connected to the inlet of the precision filter 36.

[0038] Example 2

[0039] like Figure 2As shown, the present invention discloses a high-purity nitrogen preparation device, comprising a liquid nitrogen storage and gasification device 1, a pressure reducer 2, a gas purification device 3, a pressurizing device 4, a bus 5, a high-purity nitrogen storage device 6 and a cooling device 7; the output end of the liquid nitrogen storage and gasification device 1 is connected to the input end of the gas purification device 3 through the pressure reducer 2, the output end of the gas purification device 3 is connected to the input end of the pressurizing device 4, the output end of the pressurizing device 4 is connected to the high-purity nitrogen storage device 6 through the bus 5, and the cooling device 7 is connected to the gas purification device 3 and the pressurizing device 4 respectively.

[0040] Among them, the liquid nitrogen storage and gasification device 1 includes a pressure valve, a safety valve, a pressure relief valve, a pressure gauge, an inlet and outlet liquid valve, an exhaust valve, a liquid level gauge and a vaporizer, and the pressure valve, the safety valve, the pressure relief valve, the pressure gauge, the inlet and outlet liquid valve, and the exhaust valve are all arranged at the top of the outside of the liquid nitrogen storage and gasification device 1, and the liquid level gauge and the vaporizer are arranged inside the liquid nitrogen storage and gasification device 1.

[0041] like Figure 1 As shown, the gas purification device 3 includes a heat exchanger 31, a catalytic oxidation reactor 32, a cooler 33, a first drying adsorption tower 34, a second drying adsorption tower 35, a precision filter 36 and an online detection device 37. The first outlet of the heat exchanger 31 is connected to the inlet of the catalytic oxidation reactor 32, and the outlet of the catalytic oxidation reactor 32 is further connected to the inlet of the heat exchanger 31; the second outlet of the heat exchanger 31 is connected to the inlet of the cooler 33, and the cooler 33 is connected to an external cooling device 7. The outlet of the cooler 33 is respectively connected to the bottom inlets of the first drying adsorption tower 34 and the second drying adsorption tower 35, and the top outlets of the first drying adsorption tower 34 and the second drying adsorption tower 35 are both connected to the inlet of the precision filter 36. The outlet of the precision filter 36 is respectively connected to the online detection device 37, the sampling port, and the booster 4. The online detection device 37 is, for example, a trace oxygen analyzer.

[0042] The booster device 4 is, for example, a diaphragm compressor; the high-purity nitrogen storage device 6 is, for example, a steel cylinder.

[0043] Liquid nitrogen is gasified into raw nitrogen gas through the liquid nitrogen storage and gasification device 1, and the purity of the raw nitrogen gas is ≥99.99%; the raw nitrogen gas is decompressed to 0.4-1.0Mpa through the pressure reducer 2 and then enters the heat exchanger 31 of the gas purification device 3, the heat exchanger 31 preheats the raw nitrogen gas to 280-350°C (part of the heat used for heating comes from the heat of the raw nitrogen gas that enters the heat exchanger 31 again after passing through the catalytic oxidation reactor 32), and then the raw nitrogen gas is input into the catalytic oxidation reactor 32 from the first outlet, under the conditions of reaction temperature of 280-330°C, pressure ≤1.0MPa and the catalyst being a molecular sieve, a catalytic oxidation reaction occurs to oxidize the impurities such as H2, CO, CH4, total hydrocarbons (THC) in the raw nitrogen gas to generate H2O and CO2, thereby achieving the purpose of preliminarily removing the impurities such as H2, CO, CH4, total hydrocarbons (THC) in the raw nitrogen gas.

[0044] After the impurities are initially removed by the catalytic oxidation reactor 32, the raw nitrogen gas enters the heat exchanger 31 again for initial cooling. After the initial cooling, the raw nitrogen gas enters the cooler 33 from the second outlet of the heat exchanger 31, and is further cooled in the cooler 33. The cooler 33 is connected to the external cooling device 7 (cooling water cooling device) to cool the raw nitrogen gas to room temperature. After cooling by the cooler 33, the raw nitrogen gas enters the first drying adsorption tower 34 and / or the second drying adsorption tower 35 for deep dehydration, CO2 removal, etc., to achieve further purification. The first drying adsorption tower 34 and the second drying adsorption tower 35 use molecular sieves to adsorb water and CO2 at room temperature. The saturated first drying adsorption tower 34 and the second drying adsorption tower 35 use high-temperature desorption. The desorption temperature is set to 250-300°C. The purified nitrogen is used as the regeneration gas of the drying adsorption tower. The regeneration time is 6-8h. After that, the first drying adsorption tower 34 and the second drying adsorption tower 35 are regenerated by blowing cold for 0.8-1.2h.

[0045] The raw nitrogen gas passing through the first drying adsorption tower 34 and / or the second drying adsorption tower 35 enters the precision filter 36, and dust particles are removed in the precision filter 36 to obtain high-purity nitrogen gas, and the filtration accuracy of the precision filter 36 is 0.01μm; the high-purity nitrogen gas is detected by the online detection device 37, and the purity of the high-purity nitrogen gas is ≥99.9996%, wherein O2≤0.5ppm, H2≤0.5ppm, CO2≤0.5ppm, CH4≤0.5ppm, H2O≤2ppm,, 0.03μm≤dust particles<0.2μm.

[0046] The high-purity nitrogen is pressurized by a booster device 4 (a special diaphragm compressor). The intake pressure of the high-purity nitrogen entering the booster device 4 is 0.4-0.8 MPa. The pressure of the high-purity nitrogen after being pressurized by the booster device 4 is 15 MPa. At the same time, an external cooling device 7 cools the pressurized high-purity nitrogen to room temperature. The high-purity nitrogen cooled to room temperature is filled into a high-purity nitrogen storage device 6 (such as a steel cylinder) through a bus 5 (the quantity is determined according to demand).

[0047] Example 3

[0048] like Figure 1 and Figure 2 As shown, the present invention discloses a method for preparing high-purity nitrogen, comprising the following steps:

[0049] S1: gasifying liquid nitrogen into raw nitrogen (i.e., raw gas) through a liquid nitrogen storage and gasification device 1, wherein the purity of the raw nitrogen is ≥99.99% and the outlet pressure of the raw nitrogen is 1.0-2.2 MPa; and decompressing the raw nitrogen to 0.4 MPa through a pressure reducer 2;

[0050] S2: The decompressed raw nitrogen is converted into high-purity nitrogen by the gas purification device 3;

[0051] Open the solenoid valve F1, and the decompressed raw nitrogen enters the gas purification device 3. First, the raw nitrogen is preheated to 280°C through the heat exchanger 31, and the heated raw nitrogen is input into the catalytic oxidation reactor 32 through the first outlet of the heat exchanger 31 for preliminary impurity removal. The reaction temperature in the catalytic oxidation reactor 32 is set to 300°C and the pressure is 0.4MPa. The catalyst used is a carbon-based molecular sieve, and the following reactions mainly occur:

[0052]

[0053]

[0054]

[0055]

[0056] The raw nitrogen after preliminary impurity removal comes out from the top of the catalytic oxidation reactor 32 and enters the heat exchanger 31 for preliminary cooling, and then enters the cooler 33 from the second outlet at the bottom of the heat exchanger 31. The cooler 33 uses an external cooling device 7 (cooling water cooling device) to cool the high-temperature raw nitrogen after the catalytic reaction to room temperature. The cold water of the cooling device 7 enters from the bottom of the cooler 33, and the cold water after absorbing heat returns to the cooling device 7 from the top of the cooler 33 to realize circulating cooling. The waste water in the cooling process is directly discharged from the bottom of the tower through the stop valve V1.

[0057] The raw nitrogen after impurity removal and cooling comes out from the top of the cooler 33, opens the stop valve V2 and the solenoid valve F2 or F4, and enters the first drying adsorption tower 34 or the second drying adsorption tower 35 from the bottom respectively, for room temperature adsorption (deep dehydration, CO2 removal and other further purification); the first drying adsorption tower 34 or the second drying adsorption tower 35 that is saturated with adsorption adopts high-temperature desorption, and the desorption temperature is set to 300°C. The stop valve V3 and the solenoid valves F8, F9 or F6, F7 are opened, and 10% of the purified nitrogen is used as the regeneration gas of the drying adsorption tower. The regeneration time is 8h, followed by cooling for 0.8h, the waste nitrogen is directly vented, and all valves are closed to complete the regeneration of the drying adsorption tower.

[0058] Open the solenoid valve F3 or F5, and the purified raw nitrogen comes out from the top of the first drying adsorption tower 34 or the second drying adsorption tower 35, and enters the precision filter 36, where dust particles are removed to obtain high-purity nitrogen. The filtration accuracy of the precision filter 36 is 0.01μm.

[0059] The stop valve V4 can be opened for sampling, and the stop valve V5 can be opened for online detection of the indicators of high-purity nitrogen through the online detection device 37: the purity is ≥99.9996%, among which O2≤0.5ppm, H2≤0.5ppm, CO2≤0.5ppm, CH4≤0.5ppm, H2O≤2ppm, 0.03μm≤dust particles<0.2μm; after the relevant indicators of the high-purity nitrogen are tested and qualified by the online detection device, it can be stored.

[0060] Furthermore, the method further includes step S3: opening the solenoid valve F10, and allowing high-purity nitrogen to enter the boosting device 4 from the gas purification device 3. The high-purity nitrogen is boosted by the boosting device 4, and at the same time, the external cooling device 7 reduces the temperature of the boosted high-purity nitrogen to room temperature, and is then charged into the high-purity nitrogen storage device 6 through the bus 5.

[0061] High-purity nitrogen flows out from the gas purification device 3 and enters the boosting device 4 (special diaphragm compressor) for boosting (inlet pressure 0.4MPa, and the pressure of the high-purity nitrogen after boosting is 15MPa). At the same time, the external cooling device 7 cools the high-purity nitrogen after boosting to room temperature. The high-purity nitrogen cooled to room temperature is filled into the high-purity nitrogen cylinder through the bus 5, and the pressure is 15MPa.

[0062] The method for preparing high-purity oxygen and nitrogen disclosed in the present invention is to gasify liquid nitrogen into ordinary nitrogen (≥99.99%) through a liquid nitrogen storage and gasification device; the ordinary nitrogen (i.e., raw nitrogen) enters a gas purification device, and the impurities H2, CO, CH4 and other hydrocarbons contained in the raw nitrogen react with oxygen or a catalyst to generate CO2 and H2O, and then ... The impurities such as H2O and CO2 in the gas are removed to the ppm level, and the two drying adsorption towers can alternately adsorb and regenerate. Finally, the impurities are further removed through a precision filter to obtain high-purity nitrogen. At the same time, the high-purity nitrogen obtained by the online detection device meets the technical preparation requirements, and the purity of the obtained high-purity nitrogen is ≥99.999%; after being pressurized by a membrane compressor and cooled to room temperature by an external cooling device, it is filled into a high-purity nitrogen cylinder through a bus; the method is simple and easy, and the high-purity nitrogen obtained by the method has high quality and good stability.

[0063] The present invention is described in detail above in combination with specific implementation methods and exemplary examples. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments; the above description cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, the technical solution of the present invention and its implementation methods may be subjected to a variety of equivalent substitutions, modifications or improvements, all of which fall within the scope of the present invention; the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A high-purity nitrogen production device, characterized in that: The invention comprises a gas purification device (3); the gas purification device (3) comprises a heat exchanger (31), a catalytic oxidation reactor (32), a precision filter (36), a first drying adsorption tower (34) and / or a second drying adsorption tower (35), The first outlet of the heat exchanger (31) is connected to the inlet of the catalytic oxidation reactor (32), and the outlet of the catalytic oxidation reactor (32) is connected to the inlet of the heat exchanger (31); the second outlet of the heat exchanger (31) is respectively connected to the bottom inlet of the first drying adsorption tower (34) and / or the second drying adsorption tower (35), and the top outlet of the first drying adsorption tower (34) and / or the second drying adsorption tower (35) is connected to the inlet of the precision filter (36).

2. The preparation device according to claim 1, characterized in that: The gas purification device (3) further comprises an online detection device (37), and the online detection device (37) is connected to the outlet of the precision filter (36).

3. The preparation device according to claim 2, characterized in that: The online detection device (37) is a trace oxygen analyzer.

4. The preparation device according to claim 1, characterized in that: The high-purity nitrogen production device also includes a liquid nitrogen storage and gasification device (1), a pressure reducer (2), a pressure booster (4), a bus bar (5) and a high-purity nitrogen storage device (6); The liquid nitrogen storage and gasification device (1) is connected to the heat exchanger (31) of the gas purification device (3) through a pressure reducer (2); the precision filter (36) of the gas purification device (3) is connected to the inlet of the boosting device (4), and the outlet of the boosting device (4) is connected to the high-purity nitrogen storage device (6) through a bus bar (5).

5. The preparation device according to claim 4, characterized in that: The high-purity nitrogen production device further comprises a cooling device (7), wherein the cooling device (7) is respectively connected to the gas purification device (3) and the pressurizing device (4); the gas purification device (3) further comprises a cooler (33); The second outlet of the heat exchanger (31) is connected to the inlet of the cooler (33), the cooler (33) is connected to the cooling device (7), and the outlet of the cooler (33) is respectively connected to the bottom inlet of the first drying adsorption tower (34) and / or the second drying adsorption tower (35).

6. The preparation device according to claim 4, characterized in that: The pressure boosting device (4) is a diaphragm compressor.

7. A method for producing high-purity nitrogen based on the production device according to any one of claims 1 to 6, characterized in that: The following steps are involved: S2: The raw nitrogen is converted into high-purity nitrogen by the gas purification device (3), specifically comprising: The raw nitrogen enters the gas purification device (3), and first passes through the heat exchanger (31) to preheat the raw nitrogen. The heated raw nitrogen is then input into the catalytic oxidation reactor (32) through the first outlet of the heat exchanger (31). The catalytic oxidation reactor (32) oxidizes H2, CO, CH4, and total hydrocarbons in the raw nitrogen into H2O and CO2, thereby achieving preliminary impurity removal. The raw nitrogen gas after preliminary impurity removal comes out from the top of the catalytic oxidation reactor (32) and enters the heat exchanger (31) for preliminary cooling; The raw nitrogen after impurities are removed and the temperature is reduced comes out from the second outlet at the bottom of the heat exchanger (31), and enters the first drying adsorption tower (34) and / or the second drying adsorption tower (35) from the bottom to adsorb H2O and CO2 at room temperature; the raw nitrogen comes out from the top of the first drying adsorption tower (34) and / or the second drying adsorption tower (35), and enters the precision filter (36), where dust particles are removed to obtain high-purity nitrogen.

8. The method for producing high-purity nitrogen according to claim 7, characterized in that: The step S2 further comprises: performing online detection on the high-purity nitrogen by means of an online detection device (37).

9. The method for producing high-purity nitrogen according to claim 7, characterized in that: The step S2 further comprises: the raw nitrogen after preliminary impurity removal comes out from the top of the catalytic oxidation reactor (32) and enters the heat exchanger (31) for preliminary cooling, and then enters the cooler (33) from the second outlet at the bottom of the heat exchanger (31), and the cold water of the cooling device (7) enters from the bottom of the cooler (33), and the cold water after absorbing heat returns from the top of the cooler (33) to the cooling device (7) to achieve circulating cooling; The raw nitrogen after impurities are removed and the temperature is reduced comes out from the top of the cooler (33), and enters the first drying adsorption tower (34) and / or the second drying adsorption tower (35) from the bottom to adsorb H2O and CO2 at room temperature; the raw nitrogen comes out from the top of the first drying adsorption tower (34) and / or the second drying adsorption tower (35), and enters the precision filter (36), where dust particles are removed to obtain high-purity nitrogen.

10. The method for producing high-purity nitrogen according to claim 7, characterized in that: The method for producing high-purity nitrogen further comprises S1: gasifying liquid nitrogen into raw nitrogen through the liquid nitrogen storage and gasification device (1), and decompressing the raw nitrogen through a pressure reducer (2); S2: converting the raw nitrogen into high-purity nitrogen through the gas purification device (3); S3: The high-purity nitrogen is pressurized by the pressurizing device (4), and the temperature of the pressurized high-purity nitrogen is reduced to room temperature by the cooling device (7), and then filled into the high-purity nitrogen storage device (6).

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