Nitrogen generation plant with high purity oxygen product

Abstract

This invention discloses a nitrogen production equipment that produces high-purity oxygen, relating to the field of gas preparation technology. It includes a compression cooling system, a pre-cooling purification system, a lower distillation column, an upper distillation column, a lower column condenser at the top of the lower distillation column, an upper column condenser at the top of the upper distillation column, a main heat exchanger, a subcooler, a high-purity oxygen column, a high-purity oxygen column evaporator at the bottom of the high-purity oxygen column, an ultra-pure nitrogen column, and an ultra-pure nitrogen column condenser at the top of the ultra-pure nitrogen column. The ultra-pure nitrogen column and its condenser, in conjunction with other equipment, achieve targeted removal of argon impurities, enabling stable production of ultra-high-purity nitrogen. Simultaneously, oxygen enrichment and purification are achieved in the main nitrogen production process. High-purity oxygen is co-produced through the high-purity oxygen column and its bottom evaporator, enabling a single unit to produce both ultra-high-purity nitrogen and high-purity oxygen, significantly improving the equipment's applicability and economic efficiency.

Description

Technical Field

[0001] This invention relates to the field of gas preparation technology, and in particular to a nitrogen production device that produces high-purity oxygen. Background Technology

[0002] The commonly used air separation nitrogen production technology employs a dual-tower nitrogen production system, consisting of a lower distillation column and an upper distillation column forming a two-stage distillation system. Using atmospheric air as feedstock, the air is compressed, purified, cryogenically liquefied, and then fed into the dual towers for continuous distillation separation. Nitrogen and oxygen are separated by the gas-liquid mass transfer and component enrichment effects of the two towers, resulting in high-purity nitrogen that meets industrial-grade requirements. However, this traditional dual-tower process is limited by distillation precision and impurity separation capabilities, making it difficult to achieve deep removal of argon impurities and thus unable to produce ultrapure nitrogen. Summary of the Invention

[0003] To address the above technical problems, this invention provides a nitrogen generator that produces high-purity oxygen, enabling the production of both ultra-high-purity nitrogen and high-purity oxygen. This meets the production needs of high-purity, multi-variety gases, significantly improving the equipment's applicability and economic efficiency.

[0004] To achieve the above objectives, the present invention provides the following solution: This invention provides a nitrogen production device that produces high-purity oxygen, comprising a compression cooling system, a pre-cooling purification system, a lower distillation column, an upper distillation column, a lower column condenser located at the top of the lower distillation column, an upper column condenser located at the top of the upper distillation column, a main heat exchanger, a subcooler, a high-purity oxygen column, a high-purity oxygen column evaporator located at the bottom of the high-purity oxygen column, an ultrapure nitrogen column, and an ultrapure nitrogen column condenser located at the top of the ultrapure nitrogen column. The inlet of the compression cooling system is connected to an air source, and the outlet of the compression cooling system is connected to the inlet of the pre-cooling purification system. The outlet of the precooling purification system is connected to the inlet of the first heat exchange pipeline in the main heat exchanger. The precooling purification system is used to remove CO, CO2, and H2O from the air source. The outlet of the first heat exchange pipeline in the main heat exchanger is connected to the feed inlet of the lower distillation column. The high-purity nitrogen outlet at the top of the lower distillation column is connected to the gas inlet of the lower column condenser and the inlet of the second heat exchange pipeline in the main heat exchanger. The outlet of the second heat exchange pipeline in the main heat exchanger is connected to the high-purity nitrogen product output end. The liquid outlet of the lower column condenser is connected to a reflux duct of the lower distillation column. The liquid inlet of the lower distillation column is connected to the oxygen-enriched liquid air outlet at the bottom of the lower distillation column, which is connected to the inlet of the first heat exchange pipe in the subcooler. The outlet of the first heat exchange pipe in the subcooler is connected to the liquid inlet of the lower column condenser. The gas outlet of the lower column condenser is connected to the feed inlet of the upper distillation column. The pure nitrogen outlet at the top of the upper distillation column is connected to the gas inlet of the upper column condenser. The liquid outlet of the upper column condenser is connected to the first reflux liquid inlet at the top of the upper distillation column and the other reflux liquid inlet of the lower distillation column. The bottom of the upper distillation column... The oxygen-enriched liquid outlet is connected to the inlet of the second heat exchange pipe in the subcooler, the outlet of the second heat exchange pipe in the subcooler is connected to the liquid inlet of the upper tower condenser, the gas outlet of the upper tower condenser is connected to the inlet of the third heat exchange pipe in the subcooler, and the outlet of the third heat exchange pipe in the subcooler is connected to the oxygen-enriched discharge end; the bottom of the high-purity oxygen tower has a bottom liquid oxygen outlet for outputting high-purity liquid oxygen, and the condensation side of the high-purity oxygen tower evaporator has a correspondingly provided first gas inlet, first liquid outlet, second gas inlet, and second liquid outlet;The high-purity nitrogen outlet at the top of the lower distillation column is connected to the first gas inlet on the condenser side of the high-purity oxygen tower evaporator. The first liquid outlet on the condenser side of the high-purity oxygen tower evaporator is connected to the second reflux liquid inlet at the top of the upper distillation column. The oxygen-enriched gas outlet at the bottom of the lower distillation column is connected to the second gas inlet of the high-purity oxygen tower evaporator. The second liquid outlet of the high-purity oxygen tower evaporator is connected to one reflux liquid inlet at the top of the high-purity oxygen tower. The oxygen-enriched liquid outlet at the bottom of the upper distillation column is connected to another reflux liquid inlet at the top of the high-purity oxygen tower. The lower liquid oxygen outlet at the bottom of the high-purity oxygen tower is connected to the inlet of the first conveying component. The outlet of the first conveying component is connected to the inlet of the third heat exchange pipeline in the main heat exchanger. The outlet of the third heat exchange pipeline in the main heat exchanger is connected to the high-purity oxygen product output end. The intermediate nitrogen outlet at the top of the lower distillation column is connected to the feed inlet of the ultrapure nitrogen tower, and the intermediate nitrogen outlet of the lower distillation column is located at the top of the distillation column. Above the hydrogen enrichment zone of the lower column, the gas outlet at the top of the ultrapure nitrogen column is connected to the gas inlet of the ultrapure nitrogen column condenser, the liquid outlet of the ultrapure nitrogen column condenser is connected to the reflux liquid inlet at the top of the ultrapure nitrogen column, the outlet of the first heat exchange pipe in the subcooler is connected to the liquid inlet of the ultrapure nitrogen column condenser, and the liquid nitrogen outlet on one side of the upper part of the ultrapure nitrogen column is connected to the inlet of the fourth heat exchange pipe in the main heat exchanger. Furthermore, the liquid nitrogen outlet of the ultrapure nitrogen column is located within the ultrapure nitrogen column. Above the hydrogen enrichment zone of the nitrogen tower, the outlet of the fourth heat exchanger in the main heat exchanger is connected to the ultra-high purity nitrogen product output end. The gas outlet at the top of the ultra-high purity nitrogen tower condenser is connected to the feed inlet of the upper distillation column. The hydrogen-containing nitrogen outlet on one side of the top of the ultra-high purity nitrogen tower condenser and the hydrogen-containing nitrogen outlet on one side of the top of the lower column condenser are both connected to the inlet of the fifth heat exchanger in the main heat exchanger. The outlet of the fifth heat exchanger in the main heat exchanger is connected to the hydrogen-containing nitrogen output end.

[0005] Preferably, the oxygen-enriched outlet at the top of the high-purity oxygen tower is connected to the liquid inlet of the upper tower condenser.

[0006] Preferably, the oxygen-enriched liquid outlet at the bottom of the upper distillation column is connected to the inlet of the fourth heat exchange pipeline in the subcooler, and the outlet of the fourth heat exchange pipeline in the subcooler is connected to another reflux liquid inlet at the top of the high-purity oxygen tower.

[0007] Preferably, the hydrogen-containing liquid nitrogen outlet at the bottom of the ultrapure nitrogen tower is connected to the inlet of the fifth heat exchange pipeline in the subcooler, and the outlet of the fifth heat exchange pipeline in the subcooler is connected to the third reflux inlet at the top of the distillation column.

[0008] Preferably, the system further includes a booster turbine expander, wherein the outlet of the third heat exchange pipe in the subcooler is connected to the inlet of the sixth heat exchange pipe in the main heat exchanger, the outlet of the sixth heat exchange pipe in the main heat exchanger is connected to the inlet of the expansion end of the booster turbine expander, the outlet of the expansion end of the booster turbine expander is connected to the inlet of the seventh heat exchange pipe in the main heat exchanger, and the outlet of the seventh heat exchange pipe in the main heat exchanger is connected to the oxygen-enriched discharge end.

[0009] Preferably, the seventh heat exchange pipeline in the main heat exchanger is connected to the inlet of the expansion end of the booster turbine expander via a branch pipeline, and a regulating valve is provided on the branch pipeline.

[0010] Preferably, the bottom liquid oxygen outlet is connected to a liquid oxygen pipe, and the liquid oxygen pipe is equipped with a high-purity oxygen analyzer for detecting the components of the output high-purity liquid oxygen and obtaining the detection results.

[0011] Preferably, the oxygen-enriched gas outlet of the lower distillation column is equipped with a first flow controller that adjusts the flow rate of the oxygen-enriched gas based on the detection results of the high-purity oxygen analyzer, and the high-purity nitrogen outlet of the lower distillation column is equipped with a second flow controller that adjusts the flow rate of the high-purity nitrogen based on the detection results of the high-purity oxygen analyzer.

[0012] Preferably, a second conveying component is provided on the pipeline used to connect the liquid outlet of the upper column condenser to another reflux liquid inlet of the lower distillation column.

[0013] Preferably, a first throttling valve is provided on the pipe connecting the outlet of the first heat exchange pipe in the subcooler to the liquid inlet of the lower column condenser; a second throttling valve is provided on the pipe connecting the outlet of the first heat exchange pipe in the subcooler to the liquid inlet of the ultrapure nitrogen column condenser; a third throttling valve is provided on the pipe connecting the outlet of the second heat exchange pipe in the subcooler to the liquid inlet of the upper column condenser; a fourth throttling valve is provided on the pipe connecting the second liquid outlet of the high-purity oxygen column evaporator to one reflux liquid inlet at the top of the high-purity oxygen column; and a fifth throttling valve is provided on the pipe connecting the oxygen-enriched liquid outlet at the bottom of the upper distillation column to another reflux liquid inlet at the top of the high-purity oxygen column. A sixth throttling valve is installed on the pipeline connecting the first liquid outlet on the condenser side of the high-purity oxygen tower evaporator to the second reflux inlet at the top of the upper distillation column; a seventh throttling valve is installed on the pipeline connecting the outlet of the fifth heat exchange pipeline in the subcooler to the third reflux inlet at the top of the upper distillation column; an eighth throttling valve is installed on the pipeline connecting to the outlet of the second heat exchange pipeline in the main heat exchanger; a ninth throttling valve is installed on the pipeline connecting to the outlet of the third heat exchange pipeline in the main heat exchanger; a tenth throttling valve is installed on the pipeline connecting to the outlet of the fourth heat exchange pipeline in the main heat exchanger; and an eleventh throttling valve is installed on the pipeline connecting to the outlet of the fifth heat exchange pipeline in the main heat exchanger.

[0014] The present invention achieves the following technical effects compared to the prior art: The nitrogen production equipment of the present invention, which produces high-purity oxygen, includes a compression cooling system, a pre-cooling purification system, a lower distillation column, an upper distillation column, a lower column condenser located at the top of the lower distillation column, an upper column condenser located at the top of the upper distillation column, a main heat exchanger, a subcooler, a high-purity oxygen column, a high-purity oxygen column evaporator located at the bottom of the high-purity oxygen column, an ultrapure nitrogen column, and an ultrapure nitrogen column condenser located at the top of the ultrapure nitrogen column. The ultrapure nitrogen column and its condenser, in conjunction with other equipment, achieve targeted removal of argon impurities, effectively solving the problem of insufficient distillation precision in traditional processes and enabling stable production of ultra-high-purity nitrogen. Simultaneously, oxygen enrichment and purification are completed in the main nitrogen production process. High-purity oxygen is co-produced through the high-purity oxygen column and its bottom evaporator, enabling a single unit to produce both ultra-high-purity nitrogen and high-purity oxygen. This adapts to the production needs of high-purity, multi-variety gases, significantly improving the equipment's applicability and economic efficiency. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the nitrogen generation equipment with high-purity oxygen product provided by the present invention.

[0017] Explanation of reference numerals in the attached diagram: 1. Compression cooling system; 2. Pre-cooling purification system; 3. Lower distillation column; 4. Lower column condenser; 5. Upper distillation column; 6. Upper column condenser; 7. Main heat exchanger; 8. Subcooler; 9. High-purity oxygen column; 10. High-purity oxygen column evaporator; 11. Ultra-pure nitrogen column; 12. Ultra-pure nitrogen column condenser; 13. First conveying component; 14. Second conveying component; 15. Liquid oxygen pipe; 16. Booster turbine expander; 17. Branch pipeline; 18. Control valve; 19. First throttle valve; 20. Second throttle valve; 21. Third throttle valve; 22. Fourth throttle valve; 23. Fifth throttle valve; 24. Sixth throttle valve; 25. Seventh throttle valve; 26. Eighth throttle valve; 27. Ninth throttle valve; 28. Tenth throttle valve; 29. ​​Eleventh throttle valve; 30. Twelfth throttle valve. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0019] The purpose of this invention is to provide a nitrogen production device that produces high-purity oxygen, enabling the output of ultra-high-purity nitrogen and high-purity oxygen, adapting to the production needs of high-purity and multi-category gases, and significantly improving the applicability and economic efficiency of the device.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1As shown, this embodiment provides a nitrogen generation device with high-purity oxygen product, including a compression cooling system 1, a pre-cooling purification system 2, a lower distillation column 3, an upper distillation column 5, a lower column condenser 4 located at the top of the lower distillation column 3, an upper column condenser 6 located at the top of the upper distillation column 5, a main heat exchanger 7, a subcooler 8, a high-purity oxygen column 9, a high-purity oxygen column evaporator 10 located at the bottom of the high-purity oxygen column 9, an ultrapure nitrogen column 11, and an ultrapure nitrogen column condenser 12 located at the top of the ultrapure nitrogen column 11.

[0022] The lower distillation column 3 has the following ports: feed inlet, two reflux liquid inlets at the top, high-purity nitrogen outlet at the top, oxygen-enriched liquid air outlet at the bottom, oxygen-enriched gas outlet at the bottom, and intermediate nitrogen outlet at the top.

[0023] The upper distillation column 5 has the following ports: feed inlet, three reflux liquid inlets at the top, pure nitrogen outlet at the top, oxygen-enriched liquid outlet at the bottom, and oxygen-enriched liquid outlet at the bottom.

[0024] The lower tower condenser 4 has the following ports: a gas inlet and a liquid outlet on the condensation side, a liquid inlet and a gas outlet on the evaporation side, and a hydrogen-nitrogen gas outlet on the top side.

[0025] The upper tower condenser 6 has the following ports: a gas inlet and a liquid outlet on the condensation side, and a liquid inlet and a gas outlet on the evaporation side.

[0026] The high-purity oxygen tower 9 has the following ports: two reflux liquid inlets at the top, a bottom liquid oxygen outlet for outputting high-purity liquid oxygen at the bottom, a lower liquid oxygen outlet for outputting liquid oxygen at the bottom, and an oxygen-enriched outlet at the top.

[0027] The ultrapure nitrogen tower 11 has the following ports: raw material inlet, bottom hydrogen-containing liquid nitrogen outlet, top gas outlet, top reflux liquid inlet, and upper side liquid nitrogen outlet.

[0028] The ultrapure nitrogen tower condenser 12 has the following ports: a gas inlet and a liquid outlet on the condensation side, a liquid inlet and a gas outlet on the evaporation side, and a hydrogen-containing nitrogen outlet on the top side.

[0029] The main heat exchanger 7 and the subcooler 8 each have multiple heat exchange pipelines. These heat exchange pipelines are numbered to distinguish them. The numbering order does not represent their arrangement order in the figure.

[0030] The inlet of the compression cooling system 1 is connected to an air source, and the outlet of the compression cooling system 1 is connected to the inlet of the precooling and purification system 2. The outlet of the precooling and purification system 2 is connected to the inlet of the first heat exchange pipeline in the main heat exchanger 7. The precooling and purification system 2 is used to remove CO, CO2, and H2O from the air source. The outlet of the first heat exchange pipeline in the main heat exchanger 7 is connected to the feed inlet of the lower distillation column 3. The high-purity nitrogen outlet at the top of the lower distillation column 3 is connected to the gas inlet of the lower column condenser 4 and the inlet of the second heat exchange pipeline in the main heat exchanger 7. The outlet of the second heat exchange pipeline in the main heat exchanger 7 is connected to the high-purity nitrogen product output end. The liquid outlet of the lower column condenser 4 is connected to a reflux liquid inlet of the lower distillation column 3. The oxygen-enriched liquid air outlet at the bottom of the lower distillation column 3 is connected to the inlet of the first heat exchange pipeline in the subcooler 8. The outlet of the first heat exchange pipeline in the subcooler 8 is connected to the liquid inlet of the lower column condenser 4.

[0031] The gas outlet of the lower column condenser 4 is connected to the feed inlet of the upper column 5. The pure nitrogen outlet at the top of the upper column 5 is connected to the gas inlet of the upper column condenser 6. The liquid outlet of the upper column condenser 6 is connected to the first reflux liquid inlet at the top of the upper column 5 and the other reflux liquid inlet of the lower column 3. The oxygen-enriched liquid outlet at the bottom of the upper column 5 is connected to the inlet of the second heat exchange pipeline in the subcooler 8. The outlet of the second heat exchange pipeline in the subcooler 8 is connected to the liquid inlet of the upper column condenser 6. The gas outlet of the upper column condenser 6 is connected to the inlet of the third heat exchange pipeline in the subcooler 8. The outlet of the third heat exchange pipeline in the subcooler 8 is connected to the oxygen-enriched discharge end.

[0032] The high-purity oxygen tower 9 has a bottom liquid oxygen outlet for outputting high-purity liquid oxygen. The condenser side of the high-purity oxygen tower evaporator 10 has a first gas inlet, a first liquid outlet, a second gas inlet, and a second liquid outlet. The high-purity nitrogen outlet at the top of the lower distillation column 3 is connected to the first gas inlet on the condenser side of the high-purity oxygen tower evaporator 10. The first liquid outlet on the condenser side of the high-purity oxygen tower evaporator 10 is connected to the second reflux liquid inlet at the top of the upper distillation column 5. The oxygen-enriched gas outlet at the bottom of the lower distillation column 3 is connected to the high-purity oxygen tower evaporator 10. The high-purity oxygen tower evaporator 10 is connected to the second gas inlet of the high-purity oxygen tower 9. The second liquid outlet of the high-purity oxygen tower evaporator 10 is connected to a reflux liquid inlet at the top of the high-purity oxygen tower 9. The oxygen-enriched liquid outlet at the bottom of the upper distillation column 5 is connected to another reflux liquid inlet at the top of the high-purity oxygen tower 9. The lower liquid oxygen outlet at the bottom of the high-purity oxygen tower 9 is connected to the inlet of the first conveying component 13. The outlet of the first conveying component 13 is connected to the inlet of the third heat exchange pipeline in the main heat exchanger 7. The outlet of the third heat exchange pipeline in the main heat exchanger 7 is connected to the high-purity oxygen product output end. The first conveying component 13 is used to increase the pressure of the high-purity liquid oxygen, enabling it to effectively exchange heat with other media in the main heat exchanger 7, thereby achieving the conversion of high-purity liquid oxygen into high-purity oxygen product.

[0033] The intermediate nitrogen outlet at the top of the lower distillation column 3 is connected to the feed inlet of the ultrapure nitrogen column 11, and the intermediate nitrogen outlet of the lower distillation column 3 is located above the hydrogen enrichment zone of the lower distillation column 3, that is, the location of the intermediate nitrogen outlet of the lower distillation column 3 avoids the hydrogen enrichment zone of the lower distillation column 3. The gas outlet at the top of the ultrapure nitrogen column 11 is connected to the gas inlet of the ultrapure nitrogen column condenser 12, the liquid outlet of the ultrapure nitrogen column condenser 12 is connected to the reflux liquid inlet at the top of the ultrapure nitrogen column 11, the outlet of the first heat exchange pipeline in the subcooler 8 is connected to the liquid inlet of the ultrapure nitrogen column condenser 12, and the liquid nitrogen outlet on one side of the upper part of the ultrapure nitrogen column 11 is connected to the fourth heat exchange pipeline in the main heat exchanger 7. The inlet of the ultrapure nitrogen tower 11 is connected to the hydrogen enrichment zone of the ultrapure nitrogen tower 11, meaning the liquid nitrogen outlet of the ultrapure nitrogen tower 11 is positioned to avoid the hydrogen enrichment zone. The outlet of the fourth heat exchange pipeline in the main heat exchanger 7 is connected to the ultrapure nitrogen product output end. The gas outlet at the top of the ultrapure nitrogen tower condenser 12 is connected to the feed inlet of the upper distillation column 5. The hydrogen-containing nitrogen outlet on one side of the top of the ultrapure nitrogen tower condenser 12 and the hydrogen-containing nitrogen outlet on one side of the top of the lower column condenser 4 are both connected to the inlet of the fifth heat exchange pipeline in the main heat exchanger 7. The outlet of the fifth heat exchange pipeline in the main heat exchanger 7 is connected to the hydrogen-containing nitrogen output end. The hydrogen-containing nitrogen output end can be used as a sealing gas for the liquid nitrogen pump or as instrument gas.

[0034] In this embodiment, the ultrapure nitrogen tower 11 and ultrapure nitrogen tower condenser 12, in conjunction with other equipment, achieve the directional removal of argon impurities, effectively solving the problem of insufficient distillation precision in traditional processes, and enabling the stable production of ultra-high purity nitrogen products. At the same time, the enrichment and purification of oxygen components are completed in the main nitrogen production process, and high-purity oxygen products are co-produced through the high-purity oxygen tower 9 and the high-purity oxygen tower evaporator 10 at its bottom. This allows a single set of equipment to produce both ultra-high purity nitrogen products and high-purity oxygen products, adapting to the production needs of high-purity and multi-category gases, and significantly improving the applicability and production economy of the equipment.

[0035] In this specific embodiment, the oxygen-enriched outlet at the top of the high-purity oxygen tower 9 is connected to the liquid inlet of the upper column condenser 6. The oxygen-enriched gas discharged from the top of the high-purity oxygen tower 9 is sent to the liquid inlet of the upper column condenser 6 as a cold source medium for the upper column condenser 6, utilizing its low-temperature characteristics to assist in the condensation and condensation of the pure nitrogen gas discharged from the top of the distillation column 5, thus realizing the utilization of its cooling capacity.

[0036] The oxygen-enriched liquid outlet at the bottom of the upper distillation column 5 is connected to the inlet of the fourth heat exchange pipeline in the subcooler 8, and the outlet of the fourth heat exchange pipeline in the subcooler 8 is connected to another reflux liquid inlet at the top of the high-purity oxygen column 9.

[0037] The hydrogen-containing liquid nitrogen outlet at the bottom of the ultrapure nitrogen column 11 is connected to the inlet of the fifth heat exchange pipeline in the subcooler 8, and the outlet of the fifth heat exchange pipeline in the subcooler 8 is connected to the third reflux liquid inlet at the top of the upper distillation column 5.

[0038] This embodiment also includes a booster turbine expander 16. The outlet of the third heat exchange pipeline in the subcooler 8 is connected to the inlet of the sixth heat exchange pipeline in the main heat exchanger 7. The outlet of the sixth heat exchange pipeline in the main heat exchanger 7 is connected to the inlet of the expansion end of the booster turbine expander 16. The outlet of the expansion end of the booster turbine expander 16 is connected to the inlet of the seventh heat exchange pipeline in the main heat exchanger 7. The outlet of the seventh heat exchange pipeline in the main heat exchanger 7 is connected to the oxygen-enriched discharge end.

[0039] The turboexpander 16 is used to generate cooling capacity by expanding and doing work, providing an additional cooling source for the entire system and improving the system's cooling efficiency.

[0040] The seventh heat exchange pipeline in the main heat exchanger 7 is connected to the inlet of the expansion end of the booster turbine expander 16 via a branch pipeline 17. A regulating valve 18 is installed on the branch pipeline 17, which can regulate the gas flow rate and pressure entering the expansion end of the booster turbine expander 16, thereby balancing the cooling capacity required by the system.

[0041] The bottom liquid oxygen outlet is connected to the liquid oxygen pipe 15, and the liquid oxygen pipe 15 is equipped with a high-purity oxygen analyzer for detecting the components of the output high-purity liquid oxygen and obtaining the detection results.

[0042] The oxygen-enriched gas outlet of the lower distillation column 3 is equipped with a first flow controller that adjusts the flow rate of the oxygen-enriched gas based on the detection results of the high-purity oxygen analyzer, and the high-purity nitrogen outlet of the lower distillation column 3 is equipped with a second flow controller that adjusts the flow rate of the high-purity nitrogen based on the detection results of the high-purity oxygen analyzer.

[0043] A second conveying component 14 is provided on the pipeline used to connect the liquid outlet of the upper column condenser 6 to another reflux liquid inlet of the lower distillation column 3.

[0044] In this specific embodiment, the first conveying component 13 is a first conveying pump, and the second conveying component 14 is a second conveying pump.

[0045] A first throttling valve 19 is installed on the pipeline connecting the outlet of the first heat exchange pipeline in subcooler 8 to the liquid inlet of the lower column condenser 4. A second throttling valve 20 is installed on the pipeline connecting the outlet of the first heat exchange pipeline in subcooler 8 to the liquid inlet of the ultrapure nitrogen column condenser 12. A third throttling valve 21 is installed on the pipeline connecting the outlet of the second heat exchange pipeline in subcooler 8 to the liquid inlet of the upper column condenser 6. A fourth throttling valve 22 is installed on the pipeline connecting the second liquid outlet of the high-purity oxygen column evaporator 10 to one reflux liquid inlet at the top of the high-purity oxygen column 9. A fifth throttling valve 23 is installed on the pipeline connecting the oxygen-enriched liquid outlet at the bottom of the upper distillation column 5 to another reflux liquid inlet at the top of the high-purity oxygen column 9. A sixth throttling valve 24 is installed on the pipeline connecting the first liquid outlet on the condenser side of the oxygen tower evaporator 10 to the second reflux inlet at the top of the upper distillation column 5; a seventh throttling valve 25 is installed on the pipeline connecting the outlet of the fifth heat exchange pipeline in the subcooler 8 to the third reflux inlet at the top of the upper distillation column 5; an eighth throttling valve 26 is installed on the pipeline connecting to the outlet of the second heat exchange pipeline in the main heat exchanger 7; a ninth throttling valve 27 is installed on the pipeline connecting to the outlet of the third heat exchange pipeline in the main heat exchanger 7; a tenth throttling valve 28 is installed on the pipeline connecting to the outlet of the fourth heat exchange pipeline in the main heat exchanger 7; and an eleventh throttling valve 29 is installed on the pipeline connecting to the outlet of the fifth heat exchange pipeline in the main heat exchanger 7. A twelfth throttling valve 30 is installed on the liquid oxygen pipeline 15.

[0046] A CH4 content measurement point is reserved on the pipeline connected to the oxygen-enriched liquid outlet at the bottom of the upper distillation column 5 to verify whether the position of the oxygen-enriched liquid outlet on the upper distillation column 5 is accurate.

[0047] This embodiment also includes a controller, and the first conveying component 13, the second conveying component 14, the booster turbine expander 16, the regulating valve 18, the high-purity oxygen analyzer, the first flow controller, the second flow controller, the first throttle valve 19, the second throttle valve 20, the third throttle valve 21, the fourth throttle valve 22, the fifth throttle valve 23, the sixth throttle valve 24, the seventh throttle valve 25, the eighth throttle valve 26, the ninth throttle valve 27, the tenth throttle valve 28, the eleventh throttle valve 29, and the twelfth throttle valve 30 are all connected to the controller.

[0048] The specific working process is as follows: Air is compressed, cooled, and purified before being sent to the main heat exchanger 7. During the pre-cooling and purification process, CO, CO2, and H2O are removed, resulting in a CO content ≤0.1 ppm and a CO2 content ≤0.1 ppm. In the main heat exchanger 7, the air exchanges heat with the refluxed oxygen-rich gas, high-purity oxygen product, high-purity nitrogen product, ultra-high-purity nitrogen product, and hydrogen-containing nitrogen. The air is cooled to approximately its saturation temperature and enters the bottom of the lower distillation column 3. High-purity nitrogen is obtained at the top of the lower distillation column 3. A portion of the high-purity nitrogen is extracted, reheated in the main heat exchanger 7, and then sent out as a high-purity nitrogen product. Nitrogen with a high hydrogen content is extracted from the hydrogen-containing nitrogen outlet of the lower column condenser 4, reheated in the main heat exchanger 7, and then sent out as a sealing gas for liquid nitrogen pumps or instrument gas.

[0049] The oxygen-enriched liquid air obtained at the bottom of the lower distillation column 3 is subcooled by the cooler 8 and then enters the lower column condenser 4 through the first throttling valve 19. The evaporated oxygen-enriched gas enters the upper distillation column 5 for distillation. Pure nitrogen is obtained at the top of the upper distillation column 5. The pure nitrogen in the upper distillation column 5 enters the upper column condenser 6 and is condensed into liquid nitrogen. Part of it returns to the upper distillation column 5 as reflux liquid to participate in distillation, and part of it is pressurized by the second conveying component 14 and sent to the top of the lower distillation column 3 as reflux liquid to participate in distillation.

[0050] A stream of nitrogen gas is drawn from the top of the lower distillation column 3 and sent to the condensation side of the high-purity oxygen tower evaporator 10. The nitrogen gas condenses into liquid nitrogen in the high-purity oxygen tower evaporator 10. After passing through the sixth throttle valve 24, the liquid nitrogen is sent to the upper distillation column 5 as reflux liquid to participate in the distillation. At the same time, it provides another heat source to the high-purity oxygen tower evaporator 10, causing the liquid oxygen on the evaporation side to vaporize and form the rising gas of the high-purity oxygen tower 9.

[0051] A stream of oxygen-enriched gas is drawn from the lower part of the distillation column 3 and fed into the condensation side of the high-purity oxygen tower evaporator 10. There, it condenses into liquid oxygen, simultaneously providing heat to the evaporator and causing the liquid oxygen on the evaporation side to vaporize and form the rising gas in the high-purity oxygen tower 9. The liquid oxygen is then fed to the top of the high-purity oxygen tower 9 after passing through the fourth throttle valve 22.

[0052] A stream of oxygen-enriched liquid is drawn from the lower part of the upper distillation column 5, subcooled by the cooler 8, and then sent to the top of the high-purity oxygen column 9 after passing through the fifth throttling valve 23. Inside the high-purity oxygen column 9, the reflux liquid undergoes heat and mass exchange with the rising gas, removing Ar and N from the two fractions, resulting in high-purity liquid oxygen at the bottom of the column. The high-purity liquid oxygen drawn from the lower part of the column 9 is pressurized by the first conveying component 13 and then reheated to room temperature in the main heat exchanger 7, where it is delivered as high-purity oxygen. The oxygen-enriched gas obtained at the top of the column 9 is sent to the upper column condenser 6, providing a cooling source. After evaporation in the upper column condenser 6, the gas expands in the booster turbine expander 16, providing more cooling capacity to the equipment.

[0053] The high-purity oxygen analyzer performs detection at analysis point AE. When any component of argon or methane in the product exceeds the standard, the flow rate of nitrogen FL2 drawn from the top of the lower distillation column 3 and sent to the high-purity oxygen column 9 is adjusted by the second flow controller, and the flow rate of oxygen-enriched gas FL1 drawn from the bottom of the lower distillation column 3 and sent to the condenser side of the high-purity oxygen column evaporator 10 is adjusted by the first flow controller, so as to reduce the impurities in the product and meet the product requirements.

[0054] The intermediate nitrogen outlet of the lower distillation column 3 is located at the top, avoiding the hydrogen-rich zone, and a stream of nitrogen gas is drawn and fed into the lower part of the ultrapure nitrogen column 11. The oxygen-enriched liquid air drawn from the bottom of the lower distillation column 3 enters the ultrapure nitrogen column condenser 12 through the second throttle valve 20, condensing the nitrogen gas entering the condenser 12 from the top of the ultrapure nitrogen column 11 into liquid nitrogen, forming reflux liquid that participates in the distillation. Inside the ultrapure nitrogen column 11, the reflux liquid undergoes heat and mass exchange with the rising gas, mainly removing Ar from the distillate nitrogen, thus obtaining high-purity nitrogen (containing hydrogen, with other impurities meeting ultrapure nitrogen requirements) at the top of the ultrapure nitrogen column 11. The liquid nitrogen outlet of the ultrapure nitrogen column 11 is located at the top, avoiding the hydrogen-rich zone, and draws out liquid nitrogen with a hydrogen content <0.1 ppm. The liquid nitrogen is reheated by the main heat exchanger 7 and then sent out as ultra-high purity nitrogen product. High-hydrogen-content nitrogen gas is extracted from the hydrogen-containing nitrogen outlet of the ultrapure nitrogen tower condenser, reheated by the main heat exchanger 7, and then sent out as sealing gas for the liquid nitrogen pump or instrument gas. The hydrogen-containing liquid nitrogen obtained from the bottom of the ultrapure nitrogen tower 11 is subcooled by the cooler 8 and then enters the upper distillation column 5 from the top through the seventh throttle valve 25. The hydrogen-containing liquid nitrogen after distillation in the ultrapure nitrogen tower 11 is recovered to the upper distillation column 5 and participates in the distillation in the upper distillation column 5 to maintain the cooling balance of the entire equipment.

[0055] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A nitrogen generator that produces high-purity oxygen, characterized in that, The system includes a compression cooling system, a precooling purification system, a lower distillation column, an upper distillation column, a lower column condenser located at the top of the lower distillation column, an upper column condenser located at the top of the upper distillation column, a main heat exchanger, a subcooler, a high-purity oxygen column, a high-purity oxygen column evaporator located at the bottom of the high-purity oxygen column, an ultrapure nitrogen column, and an ultrapure nitrogen column condenser located at the top of the ultrapure nitrogen column. The inlet of the compression cooling system is connected to an air source, and the outlet of the compression cooling system is connected to the inlet of the precooling purification system. The outlet of the precooling purification system is connected to the first heat exchanger in the main heat exchanger. The inlets of the heat exchange pipelines are connected, and the precooling purification system is used to remove CO, CO2, and H2O from the air source; the outlet of the first heat exchange pipeline in the main heat exchanger is connected to the feed inlet of the lower distillation column; the high-purity nitrogen outlet at the top of the lower distillation column is connected to the gas inlet of the lower column condenser and the inlet of the second heat exchange pipeline in the main heat exchanger; the outlet of the second heat exchange pipeline in the main heat exchanger is connected to the high-purity nitrogen product output end; the liquid outlet of the lower column condenser is connected to a reflux liquid inlet of the lower distillation column; the... The oxygen-enriched liquid air outlet at the bottom of the lower distillation column is connected to the inlet of the first heat exchange pipe in the subcooler. The outlet of the first heat exchange pipe in the subcooler is connected to the liquid inlet of the lower column condenser. The gas outlet of the lower column condenser is connected to the feed inlet of the upper distillation column. The pure nitrogen outlet at the top of the upper distillation column is connected to the gas inlet of the upper column condenser. The liquid outlet of the upper column condenser is connected to the first reflux inlet at the top of the upper distillation column and the other reflux inlet of the lower distillation column. The oxygen-enriched liquid outlet at the bottom of the upper distillation column... The outlet of the high-purity oxygen tower is connected to the inlet of the second heat exchange pipe in the subcooler, the outlet of the second heat exchange pipe in the subcooler is connected to the liquid inlet of the upper tower condenser, the gas outlet of the upper tower condenser is connected to the inlet of the third heat exchange pipe in the subcooler, and the outlet of the third heat exchange pipe in the subcooler is connected to the oxygen-enriched discharge end; the bottom of the high-purity oxygen tower has a bottom liquid oxygen outlet for outputting high-purity liquid oxygen, and the condensation side of the high-purity oxygen tower evaporator has a correspondingly provided first gas inlet, first liquid outlet, second gas inlet, and second liquid outlet;The high-purity nitrogen outlet at the top of the lower distillation column is connected to the first gas inlet on the condenser side of the high-purity oxygen tower evaporator. The first liquid outlet on the condenser side of the high-purity oxygen tower evaporator is connected to the second reflux liquid inlet at the top of the upper distillation column. The oxygen-enriched gas outlet at the bottom of the lower distillation column is connected to the second gas inlet of the high-purity oxygen tower evaporator. The second liquid outlet of the high-purity oxygen tower evaporator is connected to one reflux liquid inlet at the top of the high-purity oxygen tower. The oxygen-enriched liquid outlet at the bottom of the upper distillation column is connected to another reflux liquid inlet at the top of the high-purity oxygen tower. The lower liquid oxygen outlet at the bottom of the high-purity oxygen tower is connected to the inlet of the first conveying component. The outlet of the first conveying component is connected to the inlet of the third heat exchange pipeline in the main heat exchanger. The outlet of the third heat exchange pipeline in the main heat exchanger is connected to the high-purity oxygen product output end. The intermediate nitrogen outlet at the top of the lower distillation column is connected to the feed inlet of the ultrapure nitrogen tower, and the intermediate nitrogen outlet of the lower distillation column is located at the top of the distillation column. Above the hydrogen enrichment zone of the lower column, the gas outlet at the top of the ultrapure nitrogen column is connected to the gas inlet of the ultrapure nitrogen column condenser, the liquid outlet of the ultrapure nitrogen column condenser is connected to the reflux liquid inlet at the top of the ultrapure nitrogen column, the outlet of the first heat exchange pipe in the subcooler is connected to the liquid inlet of the ultrapure nitrogen column condenser, and the liquid nitrogen outlet on one side of the upper part of the ultrapure nitrogen column is connected to the inlet of the fourth heat exchange pipe in the main heat exchanger. Furthermore, the liquid nitrogen outlet of the ultrapure nitrogen column is located within the ultrapure nitrogen column. Above the hydrogen enrichment zone of the nitrogen tower, the outlet of the fourth heat exchanger in the main heat exchanger is connected to the ultra-high purity nitrogen product output end. The gas outlet at the top of the ultra-high purity nitrogen tower condenser is connected to the feed inlet of the upper distillation column. The hydrogen-containing nitrogen outlet on one side of the top of the ultra-high purity nitrogen tower condenser and the hydrogen-containing nitrogen outlet on one side of the top of the lower column condenser are both connected to the inlet of the fifth heat exchanger in the main heat exchanger. The outlet of the fifth heat exchanger in the main heat exchanger is connected to the hydrogen-containing nitrogen output end.

2. The nitrogen generator with high-purity oxygen product according to claim 1, characterized in that, The oxygen-enriched outlet at the top of the high-purity oxygen tower is connected to the liquid inlet of the upper tower condenser.

3. The nitrogen generator with high-purity oxygen product according to claim 1, characterized in that, The oxygen-enriched liquid outlet at the bottom of the upper distillation column is connected to the inlet of the fourth heat exchange pipeline in the subcooler, and the outlet of the fourth heat exchange pipeline in the subcooler is connected to another reflux liquid inlet at the top of the high-purity oxygen column.

4. The nitrogen generator with high-purity oxygen product according to claim 1, characterized in that, The hydrogen-containing liquid nitrogen outlet at the bottom of the ultrapure nitrogen tower is connected to the inlet of the fifth heat exchange pipeline in the subcooler, and the outlet of the fifth heat exchange pipeline in the subcooler is connected to the third reflux inlet at the top of the upper distillation column.

5. The nitrogen generator with high-purity oxygen product according to claim 1, characterized in that, It also includes a booster turbine expander, wherein the outlet of the third heat exchange pipe in the subcooler is connected to the inlet of the sixth heat exchange pipe in the main heat exchanger, the outlet of the sixth heat exchange pipe in the main heat exchanger is connected to the inlet of the expansion end of the booster turbine expander, the outlet of the expansion end of the booster turbine expander is connected to the inlet of the seventh heat exchange pipe in the main heat exchanger, and the outlet of the seventh heat exchange pipe in the main heat exchanger is connected to the oxygen-enriched discharge end.

6. The nitrogen generator with high-purity oxygen product according to claim 5, characterized in that, The seventh heat exchange pipeline in the main heat exchanger is connected to the inlet of the expansion end of the booster turbine expander via a branch pipeline, and a regulating valve is installed on the branch pipeline.

7. The nitrogen generator with high-purity oxygen product according to claim 1, characterized in that, The bottom liquid oxygen outlet is connected to a liquid oxygen pipe, and a high-purity oxygen analyzer is installed on the liquid oxygen pipe to perform component detection on the output high-purity liquid oxygen and obtain the detection results.

8. The nitrogen generator with high-purity oxygen product according to claim 7, characterized in that, The oxygen-enriched gas outlet of the lower distillation column is equipped with a first flow controller that adjusts the flow rate of the oxygen-enriched gas based on the detection results of the high-purity oxygen analyzer, and the high-purity nitrogen outlet of the lower distillation column is equipped with a second flow controller that adjusts the flow rate of the high-purity nitrogen based on the detection results of the high-purity oxygen analyzer.

9. The nitrogen generator with high-purity oxygen product according to claim 1, characterized in that, A second conveying component is provided on the pipeline used to connect the liquid outlet of the upper column condenser to the other reflux liquid inlet of the lower distillation column.

10. The nitrogen generator with high-purity oxygen product according to claim 4, characterized in that, A first throttling valve is installed on the pipe connecting the outlet of the first heat exchange pipe in the subcooler to the liquid inlet of the lower column condenser; a second throttling valve is installed on the pipe connecting the outlet of the first heat exchange pipe in the subcooler to the liquid inlet of the ultrapure nitrogen column condenser; a third throttling valve is installed on the pipe connecting the outlet of the second heat exchange pipe in the subcooler to the liquid inlet of the upper column condenser; a fourth throttling valve is installed on the pipe connecting the second liquid outlet of the high-purity oxygen column evaporator to one reflux liquid inlet at the top of the high-purity oxygen column; and a fifth throttling valve is installed on the pipe connecting the oxygen-enriched liquid outlet at the bottom of the upper distillation column to another reflux liquid inlet at the top of the high-purity oxygen column. A sixth throttling valve is installed on the pipeline connecting the first liquid outlet on the condenser side of the high-purity oxygen tower evaporator to the second reflux inlet at the top of the upper distillation column; a seventh throttling valve is installed on the pipeline connecting the outlet of the fifth heat exchange pipeline in the subcooler to the third reflux inlet at the top of the upper distillation column; an eighth throttling valve is installed on the pipeline connecting to the outlet of the second heat exchange pipeline in the main heat exchanger; a ninth throttling valve is installed on the pipeline connecting to the outlet of the third heat exchange pipeline in the main heat exchanger; a tenth throttling valve is installed on the pipeline connecting to the outlet of the fourth heat exchange pipeline in the main heat exchanger; and an eleventh throttling valve is installed on the pipeline connecting to the outlet of the fifth heat exchange pipeline in the main heat exchanger.

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