A dual-tower nitrogen generation system

Abstract

This invention relates to the technical field of nitrogen generation equipment, and more specifically, to a dual-tower nitrogen generation system, comprising a precooling module, a first purification module, a heat exchanger, a high-pressure nitrogen tower, a first subcooler, a first condenser-evaporator, a low-pressure nitrogen tower, a second condenser-evaporator, a high-purity oxygen tower, and a first reboiler. By setting up a high-purity oxygen tower connected to the low-pressure nitrogen tower, the entire system can not only utilize air to produce nitrogen products, but the high-purity oxygen tower can also utilize the liquid and gas in the low-pressure nitrogen tower to produce high-purity oxygen products. That is, the entire system can utilize air to simultaneously produce nitrogen products and high-purity oxygen products, making full use of air as raw material and improving the input-output ratio of raw materials.

Description

Technical Field

[0001] This invention relates to the technical field of nitrogen generation equipment, and more specifically, to a dual-tower nitrogen generation system. Background Technology

[0002] With economic development, scientific research and development in both civilian and industrial sectors are inseparable from the gas industry and cryogenic technology. Global economic growth, especially in China, has created a promising and optimistic market outlook for air separation. The petrochemical, electronics, chemical fiber, and polysilicon industries are increasingly demanding high-purity nitrogen. Nitrogen production equipment falls under the category of energy conservation and environmental protection, which is encouraged by the state. Nitrogen is chemically inert and highly resistant to chemical reactions with other substances. Therefore, nitrogen is widely used as a protective gas in the glass, oil refining, metallurgy, electronics, and chemical industries, with a very broad application prospect and rapidly growing demand.

[0003] A nitrogen production system is described. The raw air passes sequentially through an air filter, air compressor, air-cooled tower, and molecular sieve before entering the main heat exchanger. Part of the air is cooled and enters a high-pressure distillation tower, while another part is cooled and enters an expander before returning to the main heat exchanger. The nitrogen product obtained in the high-pressure distillation tower is partially reheated in the main heat exchanger and sent to the user's pipeline network, and partially exchanges heat with the oxygen-enriched liquid air in the low-pressure distillation tower. The pure liquid nitrogen obtained in the low-pressure distillation tower is pumped through a liquid nitrogen pump and a second subcooler before being sent to the high-pressure distillation tower. The oxygen-enriched liquid air from the condenser / evaporator passes through a second and third subcooler before being sent to the condenser of the low-pressure distillation tower. The oxygen-enriched oxygen generated after vaporization is returned to the third and first subcoolers and the main heat exchanger for heat recovery. Unvaporized oxygen-enriched liquid air is sent to the main heat exchanger for heat recovery.

[0004] The existing nitrogen generation systems described above can only generate nitrogen from air, which is not a sufficient utilization of air. Summary of the Invention

[0005] To overcome the problem of insufficient utilization of raw materials and mere nitrogen production in existing nitrogen generation systems, this invention provides a dual-tower nitrogen generation system.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a dual-tower nitrogen generation system, characterized in that it includes a precooling module, a first purification module, a heat exchanger, a high-pressure nitrogen tower, a first subcooler, a first condenser-evaporator, a low-pressure nitrogen tower, a second condenser-evaporator, a high-purity oxygen tower, and a first reboiler; the precooling module is connected to the first purification module; the first purification module is connected to the heat exchanger; the heat exchanger is connected to both the bottom and top of the high-pressure nitrogen tower; the first condenser-evaporator is located at the top of the high-pressure nitrogen tower and is connected to the high-pressure nitrogen tower; the first subcooler is connected to both the bottom of the high-pressure nitrogen tower and the first condenser-evaporator; the bottom of the low-pressure nitrogen tower is connected to the first condenser-evaporator; the second condenser-evaporator is located at the top of the low-pressure nitrogen tower and is connected to both the low-pressure nitrogen tower and the top of the high-pressure nitrogen tower; the first reboiler is located at the bottom of the high-purity oxygen tower and is connected to the high-purity oxygen tower; the middle part of the low-pressure nitrogen tower is connected to both the high-purity oxygen tower and the first reboiler.

[0007] The precooling module removes moisture from the air, and the first purification module removes impurities from the air. A heat exchanger heats or cools the fluid. A high-pressure nitrogen tower distills the air, with nitrogen gas generated at the top. A first subcooler cools the oxygen-rich liquid air generated at the bottom of the high-pressure nitrogen tower. A first condenser-evaporator generates reflux liquid within the high-pressure nitrogen tower for heat and mass transfer of the feed air input to the high-pressure nitrogen tower. The low-pressure nitrogen tower uses the oxygen-rich liquid air generated at the bottom of the high-pressure nitrogen tower for distillation to produce nitrogen gas. A second condenser-evaporator condenses the nitrogen gas generated in the low-pressure nitrogen tower into liquid nitrogen, which serves as reflux liquid for both the low-pressure and high-pressure nitrogen towers. The high-purity oxygen tower uses the liquid and gaseous fluids from the low-pressure nitrogen tower to distill liquid oxygen. A first reboiler condenses the gaseous fluid from the low-pressure nitrogen tower into liquid and also heats the liquid oxygen generated at the bottom of the high-purity oxygen tower to form a high-purity oxygen product and rising gas within the high-purity oxygen tower.

[0008] Furthermore, it also includes a self-pressurizing tank and a high-purity liquid oxygen tank, wherein the self-pressurizing tank is connected to the bottom of the high-purity liquid oxygen tank and the high-purity oxygen tower; and the high-purity liquid oxygen tank is connected to a heat exchanger.

[0009] Furthermore, the first purification module includes a first adsorbent and a second adsorbent internally filled with activated alumina, molecular sieve and catalyst, and the first adsorbent and the second adsorbent are connected in parallel.

[0010] Furthermore, it also includes an industrial oxygen production module that utilizes the gas from the first condenser-evaporator and the liquid from the second condenser-evaporator to produce oxygen.

[0011] Furthermore, the industrial oxygen production module includes an industrial oxygen tower, a second reboiler, a second subcooler, and a liquid oxygen pump; the second reboiler is located at the bottom of the industrial oxygen tower and is connected to the industrial oxygen tower, and the second reboiler is connected to the top of the first subcooled evaporator; the second subcooler is connected to the second reboiler, the industrial oxygen tower, and the second condenser-evaporator; the liquid oxygen pump is connected to the bottom of the industrial oxygen tower.

[0012] Furthermore, it also includes a crude krypton-xenon extraction module, which is connected to the bottom of the second condenser-evaporator.

[0013] Furthermore, the crude krypton-xenon extraction module includes a second purification module, a distillation column, and a third reboiler. The second purification module is connected to the second condenser-evaporator and the top of the distillation column. The third reboiler is located at the bottom of the distillation column and is connected to the distillation column.

[0014] Furthermore, the second purification module includes a third adsorber and a fourth adsorber filled with silica gel, wherein the third adsorber and the second adsorber are connected in parallel.

[0015] Furthermore, it also includes an expander and a silencer, both of which are connected to a heat exchanger; the first subcooler is connected to the second condenser-evaporator.

[0016] This invention also provides a method for generating nitrogen and oxygen using a dual-tower nitrogen generation system, comprising the following steps:

[0017] S1. Raw material air with a certain pressure is injected into the precooling module for dehydration treatment. After the dehydration treatment is completed, the raw material air flows from the precooling module into the first purification module for impurity removal treatment. After the impurity removal treatment is completed, purified air is obtained.

[0018] S2. Purified air enters the heat exchanger from the purification module for cooling to obtain low-temperature air. The low-temperature air enters the bottom of the high-pressure nitrogen tower from the heat exchanger and begins distillation. After distillation, ultra-high purity nitrogen is generated at the top of the high-pressure nitrogen tower, and oxygen-enriched liquid air is generated at the bottom of the high-pressure nitrogen tower. The ultra-high purity nitrogen is fed into the heat exchanger from the high-pressure nitrogen tower for reheating, and after reheating, product nitrogen is obtained. The oxygen-enriched liquid air at the bottom of the high-pressure nitrogen tower is fed into the first subcooler for cooling. After cooling, the first subcooler feeds the oxygen-enriched liquid air into the first condenser-evaporator as the cold source for the first condenser-evaporator. The oxygen-enriched liquid air evaporates in the first condenser-evaporator to become oxygen-enriched air.

[0019] S3. Oxygen-enriched air is fed into the low-pressure nitrogen tower; liquid oxygen-enriched air is generated at the bottom of the low-pressure nitrogen tower, and high-purity nitrogen is generated at the top of the low-pressure nitrogen tower. The high-purity nitrogen enters the second condenser-evaporator and is condensed into liquid nitrogen. Part of the liquid nitrogen flows back to the low-pressure nitrogen tower as reflux liquid, and the other part is pressurized and injected into the top of the high-pressure nitrogen tower as reflux liquid. The oxygen-enriched liquid air at the bottom of the low-pressure nitrogen tower is depressurized and fed into the second condenser-evaporator as a cold source. The oxygen-enriched air generated by the second condenser-evaporator is injected into the first subcooler, and then from the first subcooler into the heat exchanger. The heat exchanger reheats the oxygen-enriched air. After reheating, the heat exchanger injects the oxygen-enriched air into the expander. The expander expands the oxygen-enriched air, and then the expander feeds the expanded oxygen-enriched air back into the heat exchanger for reheating. After reheating, the heat exchanger feeds part of the oxygen-enriched air into the purification module, and the other part is discharged to the outside through the silencer.

[0020] S4. Gas and liquid are extracted from the middle of the low-pressure nitrogen tower. The liquid is fed into the top of the high-purity oxygen tower as reflux liquid and raw material liquid. The gas is fed into the first reboiler, where it is condensed into liquid and fed into the top of the high-purity oxygen tower as reflux liquid and raw material liquid. Part of the liquid oxygen generated at the bottom of the high-purity oxygen tower is fed into the first reboiler, and the other part is fed into the self-pressurizing tank. The self-pressurizing tank pressurizes the liquid oxygen and then feeds it into the high-purity liquid oxygen tank. The liquid oxygen in the high-purity liquid oxygen tank is injected into the heat exchanger for reheating. After reheating, the heat exchanger produces high-purity oxygen product.

[0021] S5. The evaporated gas generated in the first condenser-evaporator is fed into the second reboiler for condensation. The liquid generated after condensation is injected into the second subcooler for subcooling. After the subcooling is completed, the liquid is fed into the top of the industrial oxygen tower as reflux liquid and raw material liquid. The liquid generated in the second condenser-evaporator is fed into the second subcooler for subcooling. The subcooled liquid is then fed into the top of the industrial oxygen tower as reflux liquid and raw material liquid. Part of the liquid oxygen generated at the bottom of the industrial oxygen tower is heated into oxygen by the second reboiler. The oxygen remains in the industrial oxygen tower as rising steam. The other part of the liquid oxygen is pressurized by the liquid oxygen pump and injected into the heat exchanger. The heat exchanger reheats the pressurized liquid oxygen to obtain industrial oxygen.

[0022] S6. The raw material liquid at the bottom of the second condenser-evaporator is fed into the second purification module for impurity removal. After impurity removal, oxygen-enriched liquid air is obtained. The oxygen-enriched liquid air is fed into the top of the distillation column as the raw material liquid. The third reboiler provides rising steam into the distillation column. The liquid containing krypton and xenon is obtained at the bottom of the distillation column.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. By setting up a high-purity oxygen tower connected to the low-pressure nitrogen tower, the entire system can not only use air to produce nitrogen products, but the high-purity oxygen tower can also use the liquid and gas in the low-pressure nitrogen tower to produce high-purity oxygen products. That is, the entire system can use air to produce nitrogen products and high-purity oxygen products at the same time, making full use of air as raw material and improving the input-output ratio of raw materials.

[0025] 2. By setting up an industrial oxygen production module, it can use the steam in the first condenser-evaporator and the liquid at the bottom of the second condenser-evaporator to produce industrial oxygen, which further improves the input-output ratio of air as a raw material and can greatly improve the efficiency of the factory.

[0026] 3. By setting up a crude krypton-xenon extraction module, which uses the liquid at the bottom of the second condenser-evaporator to produce liquid krypton-xenon, the input-output ratio of air as raw material is further improved, which can greatly improve the efficiency of the factory. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of an embodiment of a dual-tower nitrogen generation system of the present invention;

[0028] Figure 2 yes Figure 1 An enlarged view of Part A, which includes the precooling module, air compressor, and first purification module;

[0029] Figure 3 yes Figure 1 An enlarged view of section B, which includes the heat exchanger, the first condenser-evaporator, the low-pressure nitrogen tower, the second condenser-evaporator, and the first subcooler;

[0030] Figure 4 yes Figure 1 An enlarged view of section C, which includes the high-purity oxygen tower, the first reboiler, and the industrial oxygen production module;

[0031] Figure 5 This is a schematic diagram of the crude krypton-xenon extraction module in an embodiment of a dual-tower nitrogen generation system.

[0032] In the attached diagram: 1. Precooling module; 2. First purification module; 21. First adsorber; 22. Second adsorber; 3. Heat exchanger; 4. High-pressure nitrogen tower; 5. First condenser-evaporator; 6. Low-pressure nitrogen tower; 7. Second condenser-evaporator; 8. High-purity oxygen tower; 9. First reboiler; 10. Air compressor; 11. Self-pressurizing tank; 12. High-purity liquid oxygen tank; 13. Industrial oxygen production module; 131. Industrial oxygen tower; 132. Second reboiler; 133. Second subcooler; 134. Liquid oxygen pump; 14. Expander; 15. Silencer; 16. Crude krypton-xenon extraction module; 161. Second purification module; 1611. Third adsorber; 1612. Fourth adsorber; 162. Distillation column; 163. Third reboiler; 17. First subcooler; 18. Booster pump. Detailed Implementation

[0033] The accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0034] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "long," and "short" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0035] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0036] Example 1

[0037] Reference Figures 1 to 4This is Embodiment 1 of a dual-tower nitrogen generation system of the present invention, comprising a precooling module 1, a first purification module 2, a heat exchanger 3, a high-pressure nitrogen tower 4, a first subcooler 17, a first condenser-evaporator 5, a low-pressure nitrogen tower 6, a second condenser-evaporator 7, a high-purity oxygen tower 8, and a first reboiler 9; the precooling module 1 is connected to the first purification module 2; the first purification module 2 is connected to the heat exchanger 3; the heat exchanger 3 is connected to both the bottom and top of the high-pressure nitrogen tower 4; the first condenser-evaporator 5 is located at the top of the high-pressure nitrogen tower 4 and is connected to the high-purity oxygen tower 8. The high-pressure nitrogen tower 4 is connected to the first subcooler 17, which is connected to the bottom of the high-pressure nitrogen tower 4 and the first condenser-evaporator 5. The bottom of the low-pressure nitrogen tower 6 is connected to the first condenser-evaporator 5. The second condenser-evaporator 7 is located at the top of the low-pressure nitrogen tower 6 and is connected to both the low-pressure nitrogen tower 6 and the top of the high-pressure nitrogen tower 4. The first reboiler 9 is located at the bottom of the high-purity oxygen tower 8 and is connected to the high-purity oxygen tower 8. The middle part of the low-pressure nitrogen tower 6 is connected to the high-purity oxygen tower 8 and the first reboiler 9.

[0038] Specifically, it also includes an air compressor 10, which compresses the raw air before feeding it into a precooling module 1. The precooling module 1 consists of three dry coolers connected in series, two of which are in normal operation and one is a backup. The precooling module 1 is used to remove moisture from the air, and the first purification module 2 is used to remove impurities from the air. The heat exchanger 3 is used to heat or cool the fluid. The high-pressure nitrogen tower 4 is used to distill the air, and nitrogen is generated at the top of the high-pressure nitrogen tower 4. The first subcooler 17 is used to cool the oxygen-rich liquid air generated at the bottom of the high-pressure nitrogen tower 4. The first condenser-evaporator 5 is used to generate the return gas inside the high-pressure nitrogen tower 4. The high-pressure nitrogen tower 6 uses the oxygen-rich liquid air generated at the bottom of the high-pressure nitrogen tower 4 to distill nitrogen gas; the second condenser-evaporator 7 is used to condense the nitrogen gas generated in the low-pressure nitrogen tower 6 into liquid nitrogen, which serves as the reflux liquid for the low-pressure nitrogen tower 6 and the replenishing reflux liquid for the high-pressure nitrogen tower 4; the high-purity oxygen tower 8 uses the liquid and gaseous fluids in the low-pressure nitrogen tower 6 to distill liquid oxygen; the first reboiler 9 is used to condense the gaseous fluid from the low-pressure nitrogen tower 6 into liquid, and can also heat the liquid oxygen generated at the bottom of the high-purity oxygen tower 8 into oxygen, forming a high-purity oxygen product and rising gas in the high-purity oxygen tower 8.

[0039] In this embodiment, a self-pressurizing tank 11 and a high-purity liquid oxygen tank 12 are also included. The self-pressurizing tank 11 is connected to the bottom of the high-purity liquid oxygen tank 12 and the high-purity oxygen tower 8. The high-purity liquid oxygen tank 12 is connected to the heat exchanger 3.

[0040] The self-pressurizing tank 11 pressurizes the liquid oxygen produced by the high-purity oxygen tower 8 and injects it into the high-purity oxygen tank for storage, making it convenient to use as needed. By pressurizing the liquid oxygen through the self-pressurizing tank 11, nitrogen contamination of the ppb-level high-purity oxygen can also be avoided.

[0041] In this embodiment, the first purification module 2 includes a first adsorbent 21 and a second adsorbent 22, both internally filled with activated alumina, molecular sieves, and a catalyst. The first adsorbent 21 and the second adsorbent 22 are connected in parallel. The first purification module 2 can remove impurities such as carbon dioxide, hydrocarbons, nitrous oxide, carbon monoxide, and hydrogen from the raw material air. When the first adsorbent 21 is performing adsorption, the second adsorbent 22 can be regenerated using the waste gas from the low-pressure nitrogen tower 6. The first adsorbent 21 and the second adsorbent 22 alternate between adsorption and regeneration, ensuring the continuous and stable operation of the first purification module 2.

[0042] This embodiment also includes an industrial oxygen production module that utilizes the gas from the first condenser-evaporator 5 and the liquid from the second condenser-evaporator 7 to produce oxygen. The industrial oxygen production module includes an industrial oxygen tower 131, a second reboiler 132, a second subcooler 133, and a liquid oxygen pump 134. The second reboiler 132 is located at the bottom of the industrial oxygen tower 131 and is connected to it, as well as to the top of the first subcooled evaporator. The second subcooler 133 is connected to the second reboiler 132, the industrial oxygen tower 131, and the second condenser-evaporator 7. The liquid oxygen pump 134 is connected to the bottom of the industrial oxygen tower 131. By setting up the industrial oxygen production module, industrial oxygen can be produced using the vapor in the first condenser-evaporator 5 and the liquid at the bottom of the second condenser-evaporator 7, further improving the input-output ratio of air as a raw material and significantly enhancing the factory's efficiency.

[0043] In this embodiment, an expander 14 and a silencer 15 are also included. The expander 14 and the silencer 15 are both connected to the heat exchanger 3. The first subcooler 17 is connected to the second condenser-evaporator 7.

[0044] Example 2

[0045] Reference Figures 1 to 5 This is Embodiment 2 of a dual-tower nitrogen generation system of the present invention. The difference between this embodiment and Embodiment 1 is that it further includes a crude krypton-xenon extraction module 16, which is connected to the bottom of the second condenser-evaporator 7. The crude krypton-xenon extraction module 16 includes a second purification module 161, a distillation column 162, and a third reboiler 163. The second purification module 161 is connected to the second condenser-evaporator 7 and the top of the distillation column 162; the third reboiler 163 is located at the bottom of the distillation column 162 and is connected to the distillation column 162. The crude krypton-xenon extraction module 16 utilizes the oxygen-rich liquid air at the bottom of the second condenser-evaporator 7 to generate liquid krypton-xenon.

[0046] Example 3

[0047] Reference Figures 1 to 5 This embodiment describes the usage method of the dual-tower nitrogen generation system in Embodiment 2 of the present invention, including the following process:

[0048] S1. After the air compressor 10 compresses the raw air, it is injected into the pre-cooling module 1 for dehydration treatment. After the dehydration treatment is completed, the raw air flows from the pre-cooling module 1 into the first purification module 2 for impurity removal treatment. After the impurity removal treatment is completed, purified air is obtained.

[0049] S2. Purified air enters heat exchanger 3 from the purification module for cooling to obtain low-temperature air. The low-temperature air enters the bottom of high-pressure nitrogen tower 4 from heat exchanger 3 and begins distillation. After distillation, ultra-high purity nitrogen is generated at the top of high-pressure nitrogen tower 4, and oxygen-enriched liquid air is generated at the bottom of high-pressure nitrogen tower 4. The ultra-high purity nitrogen is fed into heat exchanger 3 from high-pressure nitrogen tower 4 for reheating, and after reheating, product nitrogen is obtained. The oxygen-enriched liquid air at the bottom of high-pressure nitrogen tower 4 is fed into first subcooler 17 for cooling. After cooling, first subcooler 17 feeds the oxygen-enriched liquid air into first condenser-evaporator 5 as the cold source of first condenser-evaporator 5. The oxygen-enriched liquid air evaporates in first condenser-evaporator 5 to become oxygen-enriched air.

[0050] S3. Oxygen-enriched air is input into the low-pressure nitrogen tower 6; liquid oxygen-enriched air is generated at the bottom of the low-pressure nitrogen tower 6, and high-purity nitrogen is generated at the top of the low-pressure nitrogen tower 6. The high-purity nitrogen enters the second condenser-evaporator 7 and is condensed into liquid nitrogen. Part of the liquid nitrogen flows back to the low-pressure nitrogen tower 6 as the reflux liquid of the low-pressure nitrogen tower 6, and the other part is pressurized by the booster pump 18 and injected into the top of the high-pressure nitrogen tower 4 as the reflux liquid of the high-pressure nitrogen tower 4; the oxygen-enriched liquid air at the bottom of the low-pressure nitrogen tower 6 is depressurized and input into the second condenser-evaporator 7 as a cold source; the second The oxygen-enriched air generated by the condenser-evaporator 7 is injected into the first subcooler 17, and then injected from the first subcooler 17 into the heat exchanger 3. The heat exchanger 3 reheats the oxygen-enriched air. After reheating, the heat exchanger 3 injects the oxygen-enriched air into the expander 14. The expander 14 expands the oxygen-enriched air, and then the expander 14 inputs the expanded oxygen-enriched air back into the heat exchanger 3 for reheating. After reheating, the heat exchanger 3 inputs a portion of the oxygen-enriched air into the purification module, and the other portion is discharged to the outside through the silencer 15.

[0051] S4. Gas and liquid are extracted from the middle of the low-pressure nitrogen tower 6. The liquid is fed into the top of the high-purity oxygen tower 8 as reflux liquid and raw material liquid. The gas is fed into the first reboiler 9. The first reboiler 9 condenses the gas into liquid and feeds it into the top of the high-purity oxygen tower 8 as reflux liquid and raw material liquid. Part of the liquid oxygen generated at the bottom of the high-purity oxygen tower 8 is fed into the first reboiler 9, and the other part is fed into the self-pressurization tank 11. The self-pressurization tank 11 pressurizes the liquid oxygen and feeds it into the high-purity liquid oxygen tank 12. The liquid oxygen in the high-purity liquid oxygen tank 12 is injected into the heat exchanger 3 for reheating. After reheating, the heat exchanger 3 produces high-purity oxygen product.

[0052] S5. The evaporated gas generated in the first condenser-evaporator 5 is fed into the second reboiler 132 for condensation. The liquid generated after condensation is injected into the second subcooler 133 for subcooling. After the subcooling is completed, the liquid is fed into the top of the industrial oxygen tower 131 as reflux liquid and raw material liquid. The liquid generated in the second condenser-evaporator 7 is fed into the second subcooler 133 for subcooling. The subcooled liquid is then fed into the top of the industrial oxygen tower 131 as reflux liquid and raw material liquid. Part of the liquid oxygen generated at the bottom of the industrial oxygen tower 131 is heated into oxygen by the second reboiler 132. The oxygen remains in the industrial oxygen tower 131 as rising steam. The other part of the liquid oxygen is pressurized by the liquid oxygen pump 134 and injected into the heat exchanger 3. The heat exchanger 3 reheats the pressurized liquid oxygen to obtain industrial oxygen.

[0053] S6. The oxygen-enriched liquid air at the bottom of the second condenser-evaporator 7 is input into the second purification module 161 for impurity removal. After impurity removal, oxygen-enriched liquid air is obtained. The oxygen-enriched liquid air is input into the top of the distillation column 162 and the third reboiler 163 as the raw material liquid. The third reboiler 163 provides rising steam into the distillation column 162. The bottom of the distillation column 162 yields a liquid containing approximately 2000 ppm of krypton xenon.

[0054] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A dual-tower nitrogen generation system, characterized in that, The system includes a precooling module (1), a first purification module (2), a heat exchanger (3), a high-pressure nitrogen tower (4), a first subcooler (17), a first condenser-evaporator (5), a low-pressure nitrogen tower (6), a second condenser-evaporator (7), a high-purity oxygen tower (8), and a first reboiler (9). The precooling module (1) is connected to the first purification module (2). The first purification module (2) is connected to the heat exchanger (3). The heat exchanger (3) is connected to both the bottom and top of the high-pressure nitrogen tower (4). The first condenser-evaporator (5) is located at the top of the high-pressure nitrogen tower (4) and is connected to it. The first subcooler (17) is connected to both the bottom of the high-pressure nitrogen tower (4) and the first condenser-evaporator (5). The bottom of the low-pressure nitrogen tower (6) is connected to the first condenser-evaporator (5), and the second condenser-evaporator (7) is located at the top of the low-pressure nitrogen tower (6). The low-pressure nitrogen tower (6) is connected to the top of the high-pressure nitrogen tower (4); the first reboiler (9) is located at the bottom of the high-purity oxygen tower (8) and is connected to the high-purity oxygen tower (8); the middle part of the low-pressure nitrogen tower (6) is connected to the high-purity oxygen tower (8) and the first reboiler (9); it also includes an industrial oxygen production module that uses the gas from the first condenser-evaporator (5) and the liquid from the second condenser-evaporator (7) to produce oxygen. The oxygen production module includes an industrial oxygen tower (131), a second reboiler (132), a second subcooler (133), and a liquid oxygen pump (134); the second reboiler (132) is located at the bottom of the industrial oxygen tower (131) and is connected to the industrial oxygen tower (131), and is also connected to the top of the first condenser-evaporator (5); the second subcooler (133) and the second reboiler (132) are connected to each other. The industrial oxygen tower (131) and the second condenser-evaporator (7) are connected; the liquid oxygen pump (134) is connected to the bottom of the industrial oxygen tower (131); it also includes a crude krypton-xenon extraction module (16), which is connected to the bottom of the second condenser-evaporator (7). The crude krypton-xenon extraction module (16) includes a second purification module (161), a distillation column (162) and a third reboiler (163). The second purification module (161) is connected to the top of the second condenser-evaporator (7) and the distillation column (162). The third reboiler (163) is located at the bottom of the distillation column (162) and is connected to the distillation column (162).

2. The dual-tower nitrogen generation system according to claim 1, characterized in that, It also includes a self-pressurizing tank (11) and a high-purity liquid oxygen tank (12), wherein the self-pressurizing tank (11) is connected to the bottom of the high-purity liquid oxygen tank (12) and the high-purity oxygen tower (8); and the high-purity liquid oxygen tank (12) is connected to the heat exchanger (3).

3. The dual-tower nitrogen generation system according to claim 1, characterized in that, The first purification module (2) includes a first adsorber (21) and a second adsorber (22) filled with activated alumina, molecular sieve and catalyst. The first adsorber (21) and the second adsorber (22) are connected in parallel.

4. The dual-tower nitrogen generation system according to claim 1, characterized in that, The second purification module (161) includes a third adsorber (1611) and a fourth adsorber (1612) filled with silica gel, wherein the third adsorber (1611) and the fourth adsorber (1612) are connected in parallel.

5. The dual-tower nitrogen generation system according to claim 2, characterized in that, It also includes an expander (14) and a silencer (15), both of which are connected to the heat exchanger (3); the first subcooler (17) is connected to the second condenser-evaporator (7).

6. A method for generating nitrogen and oxygen using the dual-tower nitrogen generation system as described in claim 5, characterized in that, The process includes the following steps: S1. Raw material air with a certain pressure is injected into the precooling module (1) for dehydration treatment. After the dehydration treatment is completed, the raw material air flows from the precooling module (1) into the first purification module (2) for impurity removal treatment. After the impurity removal treatment is completed, purified air is obtained. S2. The purified air enters the heat exchanger (3) from the purification module for cooling to obtain low-temperature air. The low-temperature air enters the bottom of the high-pressure nitrogen tower (4) from the heat exchanger (3) and begins distillation. After distillation, ultra-high purity nitrogen is generated at the top of the high-pressure nitrogen tower (4), and oxygen-rich liquid air is generated at the bottom of the high-pressure nitrogen tower (4). The ultra-high purity nitrogen is fed into the heat exchanger (3) from the high-pressure nitrogen tower (4) for reheating. After reheating, product nitrogen is obtained. The oxygen-rich liquid air at the bottom of the high-pressure nitrogen tower (4) is fed into the first subcooler (17) for cooling. After cooling, the first subcooler (17) feeds the oxygen-rich liquid air into the first condenser-evaporator (5) as the cold source of the first condenser-evaporator (5). The oxygen-rich liquid air evaporates in the first condenser-evaporator (5) and becomes oxygen-rich air. S3. Oxygen-enriched air is input into the low-pressure nitrogen tower (6); liquid oxygen-enriched air is generated at the bottom of the low-pressure nitrogen tower (6), and high-purity nitrogen is generated at the top of the low-pressure nitrogen tower (6). The high-purity nitrogen enters the second condenser-evaporator (7) and is condensed into liquid nitrogen. Part of the liquid nitrogen flows back to the low-pressure nitrogen tower (6) as the reflux liquid of the low-pressure nitrogen tower (6), and the other part is pressurized and injected into the top of the high-pressure nitrogen tower (4) as the reflux liquid of the high-pressure nitrogen tower (4); the oxygen-enriched liquid air at the bottom of the low-pressure nitrogen tower (6) is depressurized and input into the second condenser-evaporator (7) as a cold source; the second condenser-evaporator ( 7) The generated oxygen-enriched air is injected into the first subcooler (17), and then injected from the first subcooler (17) into the heat exchanger (3). The heat exchanger (3) reheats the oxygen-enriched air. After reheating, the heat exchanger (3) injects the oxygen-enriched air into the expander (14). The expander (14) expands the oxygen-enriched air. Then the expander (14) inputs the expanded oxygen-enriched air into the heat exchanger (3) again for reheating. After reheating, the heat exchanger (3) inputs a portion of the oxygen-enriched air into the purification module, and the other portion is discharged into the outside through the silencer (15). S4. Gas and liquid are extracted from the middle of the low-pressure nitrogen tower (6). The liquid is fed into the top of the high-purity oxygen tower (8) as reflux liquid and raw material liquid. The gas is fed into the first reboiler (9). The first reboiler (9) condenses the gas into liquid and feeds it into the top of the high-purity oxygen tower (8) as reflux liquid and raw material liquid. Part of the liquid oxygen generated at the bottom of the high-purity oxygen tower (8) is fed into the first reboiler (9), and the other part is fed into the self-pressurizing tank (11). The self-pressurizing tank (11) pressurizes the liquid oxygen and feeds it into the high-purity liquid oxygen tank (12). The liquid oxygen in the high-purity liquid oxygen tank (12) is injected into the heat exchanger (3) for reheating. After reheating, the heat exchanger (3) produces high-purity oxygen product. S5. The evaporated gas generated in the first condenser evaporator (5) is fed into the second reboiler (132) for condensation. The liquid generated after condensation is injected into the second subcooler (133) for subcooling. After the subcooling operation is completed, the liquid is fed into the top of the industrial oxygen tower (131) as reflux liquid and raw material liquid. The liquid generated by the second condenser evaporator (7) is fed into the second subcooler (133) for subcooling, and then the subcooled liquid is fed into the top of the industrial oxygen tower (131) as reflux liquid and raw material liquid; part of the liquid oxygen generated at the bottom of the industrial oxygen tower (131) is heated into oxygen by the second reboiler (132), and the oxygen remains in the industrial oxygen tower (131) as rising steam, while the other part of the liquid oxygen is pressurized by the liquid oxygen pump (134) and injected into the heat exchanger (3). The heat exchanger (3) reheats the pressurized liquid oxygen to obtain industrial oxygen. S6. The raw material liquid at the bottom of the second condenser evaporator (7) is input into the second purification module (161) for impurity removal. After impurity removal, oxygen-enriched liquid air is obtained. The oxygen-enriched liquid air is input into the top of the distillation column (162) as raw material liquid. The third reboiler (163) provides rising steam into the distillation column (162). The liquid containing krypton xenon is obtained at the bottom of the distillation column (162).

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