A low-energy consumption ultra-high pressure air separation oxygen and nitrogen production system and method

Abstract

The present invention discloses a low-energy consumption ultra-high pressure air separation oxygen and nitrogen production system and method. In the system, after being filtered, compressed, pre-cooled and purified, one part of the air goes to the plate-fin heat exchanger and the lower tower, one part goes to the booster, the plate-fin heat exchanger and the expansion end, and the rest goes to the booster, the booster end and the coiled heat exchanger. One part of the coiled heat exchanger is drawn to the plate-fin heat exchanger and the separation tank, and the rest goes to the separation tank; the oxygen-rich liquid air and lean liquid nitrogen in the lower tower go from the supercooler to the upper tower, the pure liquid nitrogen part goes to the coiled heat exchanger through the ultra-high pressure nitrogen pump, and part goes to the upper tower or output; the liquid oxygen part at the bottom of the upper tower is output and partly output through the ultra-high pressure liquid oxygen pump and the coiled heat exchanger; the dirty nitrogen gas at the top of the upper tower and the pure nitrogen gas at the top go through the cooler and the plate-fin heat exchanger, partly to the molecular sieve heater, and partly to the air pre-cooling component. Through the technical scheme of the present invention, the comprehensive unit energy consumption is reduced under the same product parameters, the production cost is reduced, and the safety and stability of the production process are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of air separation, and in particular to a low-energy consumption ultra-high pressure air separation oxygen and nitrogen production system and a low-energy consumption ultra-high pressure air separation oxygen and nitrogen production method. Background Art

[0002] Coal gasification technology (UCG) is a process of controlled combustion of underground coal to produce combustible gas through thermal and chemical effects on coal. The promotion of UCG technology can ease the tight supply of natural gas in my country and reduce external dependence on energy. In recent years, underground coal gasification has developed rapidly in the United Kingdom, Australia, South Africa, Canada, the United States, and Central Europe, with more than 50 pilot projects underway. In the UCG process, pure oxygen (≥99.6%) and water need to be sent into the middle and deep coal seams under a certain pressure as raw materials and oxidants to react with coal to generate gases such as hydrogen, carbon monoxide and methane; at the same time, pure nitrogen (≥99.99%) is also required as a protective gas, so it is necessary to include an air separation process that can produce high-pressure oxygen and nitrogen in the UCG process.

[0003] In the existing air separation oxygen and nitrogen production processes and equipment, the unit energy consumption is relatively high and cannot be applied to the preparation of ultra-high pressure oxygen and nitrogen.

[0004] Internal compression is to compress the liquid product with a pump, and then send it outside the device after reheating and gasification. Relatively speaking, internal compression of oxygen is safer, especially in the field of large-scale equipment, where the advantages of high pressure and large flow are more prominent. Summary of the invention

[0005] In view of the above problems, the present invention provides a low-energy consumption ultra-high pressure air separation oxygen and nitrogen production system and method, which uses a plate-fin heat exchanger and a coiled tube heat exchanger arranged in parallel to exchange heat for air of different pressures and different preparation purposes according to different flow ratios, and outputs different products prepared by the upper tower and the lower tower through different pipelines according to their respective properties and states. While meeting the needs for oxygen and nitrogen products of different pressures and different purities, deep cold and low temperature distillation and process flow are adopted, which reduces the comprehensive unit energy consumption of the air separation equipment under the same product parameters, reduces the production cost, and has good energy-saving, emission reduction and environmental protection effects, effectively improves the production efficiency and economic benefits, and ensures the safety and stability of the production process.

[0006] To achieve the above-mentioned purpose, the present invention provides a low-energy consumption ultra-high pressure air separation oxygen and nitrogen production system, comprising: an air filter, an air compressor, an air precooling component, a molecular sieve, an air booster, an expander, a plate-fin heat exchanger, a coiled heat exchanger, a separation tank, a supercooler, an ultra-high pressure oxygen pump and an ultra-high pressure nitrogen pump; the outlet of the air filter is connected to the outlet of the air compressor, the air precooling component is connected to the air compressor and precools the compressed air output by the air compressor and outputs it to the molecular sieve; the molecular sieve purifies the compressed air and outputs it to the air booster and the plate-fin heat exchanger, the air booster divides the pressurized air into two streams, one of which is transported to the plate-fin heat exchanger and then to the expansion end of the expander, and the other is transported to the boosting end of the expander and then to the coiled heat exchanger, and the air transported to the coiled heat exchanger is further divided into two streams, one of which is transported to the plate-fin heat exchanger for heat exchange and then to the The air in the lower tower is subjected to the preliminary distillation of the air in the lower tower, and the oxygen-rich liquid air and lean liquid nitrogen are transported to the upper tower by the supercooler. The pure liquid nitrogen obtained by distillation is divided into two streams, one of which is pressurized by the ultra-high pressure nitrogen pump and transported to the coil-type heat exchanger to obtain ultra-high pressure nitrogen, and the other is partially transported to the upper tower through the supercooler and partially output as a liquid nitrogen product. The liquid oxygen obtained at the bottom of the upper tower after distillation in the upper tower is partially pressurized by the ultra-high pressure liquid oxygen pump and enters the oxygen pipeline network, and partially output as a liquid oxygen product. The dirty nitrogen obtained at the upper part of the upper tower and the pure nitrogen obtained at the top of the upper tower are reheated by the supercooler and the plate-fin heat exchanger, and partially transported to the heater of the molecular sieve and partially transported to the air precooling component.

[0007] In the above technical solution, preferably, the molecular sieves are arranged in two groups in parallel, one of the two groups of molecular sieves is in the molecular sieve purification process, and the other group is in the regeneration process, and the two groups of molecular sieves are used alternately.

[0008] In the above technical scheme, preferably, the plate-fin heat exchanger receives two streams of air before and after the supercharging of the air supercharger respectively, the air before the supercharging is transported to the separation tank after heat exchange through the plate-fin heat exchanger, and the air after the supercharging is transported to the expansion end of the expander after heat exchange through the plate-fin heat exchanger; the plate-fin heat exchanger also receives a stream of air after heat exchange in the coil-wound heat exchanger, and transports it to the separation tank after heat exchange through the plate-fin heat exchanger; the plate-fin heat exchanger receives the dirty nitrogen gas output from the upper part of the upper tower and after heat exchange through the supercooler, and a part of it is output to the water cooling tower of the air precooling component after heat exchange through the plate-fin heat exchanger, and a part of it is output as regenerated dirty nitrogen gas, and it also receives the pure nitrogen gas output from the top of the upper tower and after heat exchange through the supercooler, and a part of it is output as normal pressure nitrogen gas after heat exchange through the plate-fin heat exchanger, and a part of it is output to the water cooling tower of the air precooling component.

[0009] In the above technical solution, preferably, the coiled heat exchanger receives the air pressurized by the boosting end of the expander and divides it into two streams, one of which is transported to the plate-fin heat exchanger for heat exchange and then transported to the separation tank, and the other is output from the coiled heat exchanger and then transported to the separation tank; the coiled heat exchanger also receives liquid oxygen output from the bottom of the upper tower and compressed by the ultra-high pressure liquid oxygen pump, and outputs it as ultra-high pressure oxygen after heat exchange in the coiled heat exchanger; the coiled heat exchanger also receives liquid nitrogen extracted from the top of the lower tower and compressed by the ultra-high pressure nitrogen pump, and outputs it as ultra-high pressure nitrogen after heat exchange in the coiled heat exchanger.

[0010] In the above technical solution, preferably, the air precooling component includes an air cooling tower, a refrigerator and a water cooling tower. The air pressurized by the air compressor is transported to the air cooling tower, the water in the water cooling tower is frozen by the refrigerator and then transported to the air cooling tower, and the air in the air cooling tower passes through the chilled water from bottom to top and is output to the molecular sieve.

[0011] In the above technical solution, preferably, the flow ratio of the two air streams before and after the boosting of the air booster, the flow ratio of the two air streams flowing to the plate-fin heat exchanger and the expander respectively, and the flow ratio of the two air streams separated in the coil-wound heat exchanger are adjusted according to the purity, pressure and process conditions of the oxygen and nitrogen to be prepared.

[0012] The present invention also proposes a low-energy consumption ultra-high pressure air separation oxygen and nitrogen production method, which is applied to the low-energy consumption ultra-high pressure air separation oxygen and nitrogen production system proposed in any one of the above technical solutions, including: after filtering the raw air through an air filter, inputting it into an air compressor for pressurization; conveying the pressurized air to an air precooling component for cooling and cleaning, and then inputting it into a molecular sieve for purification; dividing the purified air into two streams, one of which is conveyed to a plate-fin heat exchanger for heat exchange and then output to a separation tank, and the other is conveyed to an air booster for pressurization; the air pressurized by the air booster is divided into two streams, one of which is conveyed to the plate-fin heat exchanger for heat exchange and then conveyed to the expansion end of an expander and then output to the separation tank, and the other is conveyed to the boosting end of the expander for pressurization and then output to a coil heat exchanger; the air output to the coil heat exchanger is further divided into two streams, one of which is conveyed to the plate-fin heat exchanger for heat exchange and then conveyed to the separation tank, and the other is output to the coil heat exchanger. The air in the lower tower is subjected to preliminary rectification and the oxygen-rich liquid air and lean liquid nitrogen are transported to the upper tower by the supercooler. The pure liquid nitrogen obtained by rectification is divided into two streams, one of which is pressurized by the ultra-high pressure nitrogen pump and then transported to the coil-type heat exchanger to obtain ultra-high pressure nitrogen, and the other stream is partially transported to the upper tower through the supercooler and partially output as a liquid nitrogen product. The liquid oxygen obtained at the bottom of the upper tower after rectification in the upper tower is pressurized by the ultra-high pressure liquid oxygen pump and partially enters the coil-type heat exchanger and enters the oxygen pipeline network, and partially output as a liquid oxygen product. The dirty nitrogen obtained at the upper part of the upper tower and the pure nitrogen obtained at the top of the upper tower are reheated by the supercooler and the plate-fin heat exchanger, and then partially transported to the heater of the molecular sieve and partially transported to the air precooling component.

[0013] In the above technical solution, preferably, two groups of the molecular sieves are arranged in parallel, one group is in the molecular sieve purification process, and the other group is in the regeneration process, and the two groups of the molecular sieves are used alternately.

[0014] In the above technical scheme, preferably, the plate-fin heat exchanger receives the dirty nitrogen output from the upper part of the upper tower and cooled and throttled by the supercooler, and after heat exchange in the plate-fin heat exchanger, a part of it is output to the water cooling tower of the air precooling component, and a part of it enters the electric heater for heating as a regeneration gas source, and also receives the pure nitrogen output from the top of the upper tower and cooled and throttled by the corresponding supercooler, and after heat exchange in the plate-fin heat exchanger, a part of it is output as a product and a part of it is output to the water cooling tower of the air precooling component; the coil-wrap heat exchanger receives the liquid oxygen output from the bottom of the upper tower and compressed by the ultra-high pressure liquid oxygen pump, and outputs it as ultra-high pressure oxygen after heat exchange in the coil-wrap heat exchanger, and also receives the liquid nitrogen extracted from the top of the lower tower and compressed by the ultra-high pressure nitrogen pump, and outputs it as ultra-high pressure nitrogen after heat exchange in the coil-wrap heat exchanger.

[0015] In the above technical solution, preferably, the flow ratio of the two air streams before and after the boosting of the air booster, the flow ratio of the two air streams flowing to the plate-fin heat exchanger and the expander respectively, and the flow ratio of the two air streams separated in the coil-wound heat exchanger are adjusted according to the purity, pressure and process conditions of the oxygen and nitrogen to be prepared.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: heat is exchanged for air of different pressures and preparation purposes at different flow ratios through the plate-fin heat exchanger and the coil heat exchanger arranged in parallel; different products prepared by the upper tower and the lower tower are output through different pipelines according to their respective properties and states, while meeting the demand for oxygen and nitrogen products of different pressures and purities, and deep cryogenic distillation and process flow are adopted, which reduces the comprehensive unit energy consumption of the air separation equipment under the same product parameters, reduces the production cost, and has good energy-saving, emission reduction and environmental protection effects, effectively improves the production efficiency and economic benefits, and ensures the safety and stability of the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a schematic diagram of a process flow of a low-energy consumption ultra-high pressure air separation oxygen and nitrogen production system disclosed in an embodiment of the present invention.

[0018] In the figure, the corresponding relationship between each component and the reference numeral is as follows:

[0019] 11. Air filter, 12. Air compressor, 13. Air cooling tower, 14. Water cooling tower, 15. Refrigerator, 16. Molecular sieve, 17. Air booster, 18. Plate-fin heat exchanger, 19. Wound tube heat exchanger, 20. Booster end, 21. Expansion end, 22. Upper tower, 23. Condenser evaporator, 24. Subcooler, 25. Ultra-high pressure oxygen pump, 26. Ultra-high pressure nitrogen pump, 27. Lower tower. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0022] like Figure 1 As shown, a low-energy consumption ultra-high pressure air separation oxygen and nitrogen production system provided by the present invention comprises: an air filter 11, an air compressor 12, an air pre-cooling component, a molecular sieve 16, an air booster 17, an expander, a plate-fin heat exchanger 18, a coiled heat exchanger 19, a separation tank, a supercooler 24, an ultra-high pressure oxygen pump 25, an ultra-high pressure nitrogen pump 26, 27. A lower tower;

[0023] The outlet of the air filter 11 is connected to the outlet of the air compressor 12, and the raw air after removing dust and other mechanical impurities is transported to the air compressor 12 for pressurization, preferably to 5 barG. The air precooling component is connected to the air compressor 12, so that the compressed air output by the air compressor 12 is precooled and then output to the molecular sieve 16, and the carbon dioxide, hydrocarbons and moisture in the air are adsorbed, so that the H2O and CO2 contents are reduced to less than 1 ppm, that is, it is considered that the carbon dioxide, acetylene and water in the air are removed;

[0024] The compressed air is purified by the molecular sieve 16 and then output to the air booster 17. The air booster 17 divides the boosted air into two streams, one of which is transported to the plate-fin heat exchanger 18 and then to the expansion end 21 of the expander, and the other is transported to the boosting end 20 of the expander for compression and then to the coil-wound heat exchanger 19 for heat exchange. The air transported to the coil-wound heat exchanger 19 is further divided into two streams, one of which is transported to the plate-fin heat exchanger 18 for heat exchange and throttling and then to the separation tank, and the other continues to exchange heat in the coil-wound heat exchanger 19, and after throttling, part of it is output to the separation tank, and part of it is output to the supercooler 24, and then transported to the upper tower 22 after cooling; wherein, the flow ratio of the two air streams separated after the boosting by the air booster 17 and the flow ratio of the two air streams separated by the coil-wound heat exchanger 19 are adjusted according to the purity, pressure and process conditions of the oxygen and nitrogen to be prepared. Since the plate-fin heat exchanger 18 has lower energy consumption but weaker heat exchange capacity than the coil-wound heat exchanger 19, the air that does not need to be heated by the coil-wound heat exchanger 19 is heated in the plate-fin heat exchanger 18, thereby reducing energy consumption overall.

[0025] After the gas-liquid separation in the separation tank, a part of the air and liquid air enter the lower tower 27, and the other part of the liquid air enters the subcooler 24 and enters the upper tower 22 after cooling and throttling;

[0026] The oxygen-rich liquid air and lean liquid nitrogen obtained by preliminary distillation of the air in the lower tower 27 are supercooled by the supercooler 24 and then throttled and transported to the upper tower 22. After further distillation in the upper tower 22, the pure liquid nitrogen obtained by distillation is divided into two streams. One stream is pressurized by the ultra-high pressure nitrogen pump 26 and then transported to the coil heat exchanger 19. After reheating, it exits the cold box and enters the nitrogen pipeline network to obtain ultra-high pressure nitrogen. The other stream of liquid nitrogen is supercooled by the supercooler 24 and then partly transported to the upper tower 22 and partly outputted to the liquid nitrogen storage tank LIN as a liquid nitrogen product.

[0027] After the upper tower 22 is rectified, the liquid oxygen obtained at the bottom of the upper tower 22 is pressurized by the ultra-high pressure liquid oxygen pump and then partially enters the coiled heat exchanger 19 for heat exchange, and after reheating, it exits the cold box and enters the oxygen network. Another part of the liquid oxygen is extracted and supercooled and output to the liquid oxygen storage tank LOX as a liquid oxygen product;

[0028] The contaminated nitrogen gas obtained at the upper part of the upper tower 22 is reheated by the cooler 24 and the plate-fin heat exchanger 18 and then discharged from the cold box. Part of the contaminated nitrogen gas is transported to the heater EH of the molecular sieve 16 as the regeneration gas of the molecular sieve 16, and the rest of the contaminated nitrogen gas is transported to the water cooling tower 14 of the air precooling assembly;

[0029] The pure nitrogen obtained at the top of the upper tower 22 is reheated by the cooler 24 and the plate-fin heat exchanger 18 and then discharged from the cold box as a reserved nitrogen product. When needed, it is sent to the user's nitrogen pipeline network, and when not needed, it is sent to the water-cooled tower 14.

[0030] In this embodiment, the plate-fin heat exchanger 18 and the coil heat exchanger 19 arranged in parallel are used to exchange heat for air of different pressures and preparation purposes at different flow ratios. Different products prepared by the upper tower 22 and the lower tower 27 are output through different pipelines according to their respective properties and states. While meeting the demand for oxygen and nitrogen products of different pressures and purities, deep cryogenic distillation and process flow are adopted to reduce the comprehensive unit energy consumption of the air separation equipment under the same product parameters, reduce the production cost, and achieve good energy-saving, emission reduction and environmental protection effects, effectively improve the production efficiency and economic benefits, and ensure the safety and stability of the production process.

[0031] In the above embodiment, preferably, the molecular sieves 16 are arranged in two groups in parallel, one of the two groups of molecular sieves 16 is in the molecular sieve purification process, and the other group is in the regeneration process. The two groups of molecular sieves 16 are used alternately to ensure the continuity of the air separation process.

[0032] In the above embodiment, preferably, the plate-fin heat exchanger 18 receives two streams of air before and after the supercharging of the air supercharger 17, respectively. The air before the supercharging is transported to the separation tank after heat exchange in the plate-fin heat exchanger 18, and the air after the supercharging is transported to the expansion end 21 of the expander after heat exchange in the plate-fin heat exchanger 18; the plate-fin heat exchanger 18 also receives a stream of air after heat exchange in the coil-wound heat exchanger 19, and transports it to the separation tank after heat exchange in the plate-fin heat exchanger 18; the plate-fin heat exchanger 18 receives the dirty nitrogen gas output from the upper part of the upper tower 22 and after heat exchange in the cooler 24, and a part of it is output to the water cooling tower 14 of the air precooling component after heat exchange in the plate-fin heat exchanger 18, and a part of it is output as regenerated dirty nitrogen gas, and it also receives the pure nitrogen gas output from the top of the upper tower 22 and after heat exchange in the corresponding subcooler 24, and a part of it is output as atmospheric pressure nitrogen after heat exchange in the plate-fin heat exchanger 18, and a part of it is output to the water cooling tower 14 of the air precooling component.

[0033] In the above embodiment, preferably, the coiled heat exchanger 19 receives the air pressurized by the boosting end 20 of the expander and divides it into two streams, one of which is transported to the plate-fin heat exchanger 18 for heat exchange and then transported to the separation tank, and the other is output from the coiled heat exchanger 19 and then transported to the separation tank; the coiled heat exchanger 19 also receives the liquid oxygen output from the bottom of the upper tower 22 and compressed by the ultra-high pressure liquid oxygen pump, and outputs it as ultra-high pressure oxygen after heat exchange in the coiled heat exchanger 19; the coiled heat exchanger 19 also receives the liquid nitrogen extracted from the top of the lower tower 27 and compressed by the ultra-high pressure nitrogen pump 26, and outputs it as ultra-high pressure nitrogen after heat exchange in the coiled heat exchanger 19.

[0034] In addition, a condenser evaporator 23 is provided between the upper tower 22 and the lower tower 27. The condenser evaporator 23 evaporates the liquid oxygen at the bottom of the upper tower 22 and condenses the gaseous nitrogen in the lower tower 27 through heat exchange.

[0035] In the above embodiment, preferably, the air precooling component includes an air cooling tower 13, a refrigerator 15 and a water cooling tower 14. The air pressurized by the air compressor 12 is transported to the air cooling tower 13, and the water in the water cooling tower 14 is pumped by the cooling water pump WP2 to the refrigerator 15 for freezing and then transported to the air cooling tower 13. The air in the air cooling tower 13 passes from bottom to top, first through the normal temperature water input by the normal temperature water pump WP1 for cleaning, then through the chilled water input by the refrigerator 15 for cooling, and then output to the molecular sieve 16, and is cleaned while being cooled.

[0036] In the above embodiment, preferably, the flow ratio of the two air streams before and after the boosting by the air booster 17, the flow ratio of the two air streams flowing to the plate-fin heat exchanger 18 and the expander respectively, and the flow ratio of the two air streams separated in the coil heat exchanger 19 are adjusted according to the purity, pressure and process conditions of the oxygen and nitrogen to be prepared, so as to reduce the comprehensive unit energy consumption of the air separation equipment and reduce the production cost under the same product parameters.

[0037] The present invention further proposes a low-energy consumption ultra-high pressure air separation oxygen and nitrogen production method, which is applied to the low-energy consumption ultra-high pressure air separation oxygen and nitrogen production system proposed in any one of the above embodiments, comprising:

[0038] The raw air is filtered through an air filter 11 and then input into an air compressor 12 for pressurization;

[0039] The pressurized air is transported to the air pre-cooling assembly for cooling and cleaning, and then input into the molecular sieve 16 for purification;

[0040] The purified air is divided into two streams, one of which is sent to the plate-fin heat exchanger 18 for heat exchange and then output to the separation tank, and the other is sent to the air booster 17 for pressurization;

[0041] The air pressurized by the air compressor 17 is divided into two streams. One stream is delivered to the plate-fin heat exchanger 18 for heat exchange and then delivered to the expansion end 21 of the expander and then output to the separation tank. The other stream is delivered to the pressurizing end 20 of the expander for pressurization and then output to the coil heat exchanger 19.

[0042] The air output to the coiled heat exchanger 19 is divided into two streams, one stream is delivered to the plate-fin heat exchanger 18 for heat exchange and then delivered to the separation tank, and the other stream is delivered to the separation tank after outputting the coiled heat exchanger 19;

[0043] After the gas-liquid separation in the separator, a part of the air and liquid air enters the lower tower 27, and the other part of the liquid air is cooled and throttled by the subcooler 24 and then transported to the upper tower 22;

[0044] The oxygen-rich liquid air and lean liquid nitrogen obtained by preliminary distillation of the air in the lower tower 27 are transported to the upper tower 22 through the subcooler 24. The pure liquid nitrogen obtained by distillation is divided into two streams. One stream is pressurized by the ultra-high pressure nitrogen pump 26 and transported to the coil heat exchanger 19 to obtain ultra-high pressure nitrogen gas. The other stream is partially transported to the upper tower 22 through the subcooler 24 and partially output as liquid nitrogen product.

[0045] After the upper tower 22 is rectified, the liquid oxygen obtained at the bottom of the upper tower 22 is pressurized by the ultra-high pressure oxygen pump 25, and then part of it enters the coiled heat exchanger 19 and enters the oxygen network, and part of it is output as a liquid oxygen product;

[0046] The contaminated nitrogen gas obtained at the upper part of the upper tower 22 and the pure nitrogen gas obtained at the top of the upper tower 22 are reheated by the cooler 24 and the plate-fin heat exchanger 18, and then partly transported to the heater of the molecular sieve 16 and partly transported to the air precooling component.

[0047] In this embodiment, the plate-fin heat exchanger 18 and the coil heat exchanger 19 arranged in parallel are used to exchange heat for air of different pressures and preparation purposes at different flow ratios. Different products prepared by the upper tower 22 and the lower tower 27 are output through different pipelines according to their respective properties and states. While meeting the demand for oxygen and nitrogen products of different pressures and purities, deep cryogenic distillation and process flow are adopted to reduce the comprehensive unit energy consumption of the air separation equipment under the same product parameters, reduce the production cost, and achieve good energy-saving, emission reduction and environmental protection effects, effectively improve the production efficiency and economic benefits, and ensure the safety and stability of the production process.

[0048] In the above embodiment, preferably, two groups of molecular sieves 16 are arranged in parallel, one group is in the molecular sieve 16 purification process, and the other group is in the regeneration process. The two groups of molecular sieves 16 are used alternately to ensure the continuity of the air separation process.

[0049] In the above embodiment, preferably, the plate-fin heat exchanger 18 receives the dirty nitrogen output from the upper part of the upper tower 22 and cooled and throttled by the cooler 24, and after heat exchange in the plate-fin heat exchanger 18, a part of it is output to the water cooling tower 14 of the air precooling component, and a part enters the electric heater EH for heating as a regeneration gas source, and also receives the pure nitrogen output from the top of the upper tower 22 and cooled and throttled by the corresponding supercooler 24, and after heat exchange in the plate-fin heat exchanger 18, a part of it is output as a product, and a part of it is output to the water cooling tower 14 of the air precooling component; the coiled heat exchanger 19 receives the liquid oxygen output from the bottom of the upper tower 22 and compressed by the ultra-high pressure oxygen pump 25, and outputs it as ultra-high pressure oxygen after heat exchange in the coiled heat exchanger 19, and also receives the liquid nitrogen extracted from the top of the lower tower 27 and compressed by the ultra-high pressure nitrogen pump 26, and outputs it as ultra-high pressure nitrogen after heat exchange in the coiled heat exchanger 19.

[0050] In the above embodiment, preferably, the flow ratio of the two air streams before and after the boosting by the air booster 17, the flow ratio of the two air streams flowing to the plate-fin heat exchanger 18 and the expander respectively, and the flow ratio of the two air streams separated in the coil heat exchanger 19 are adjusted according to the purity, pressure and process conditions of the oxygen and nitrogen to be prepared, so as to reduce the comprehensive unit energy consumption of the air separation equipment and reduce the production cost under the same product parameters.

[0051] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low energy consumption ultra-high pressure air separation oxygen and nitrogen production system, characterized in that: include: Air filters, air compressors, air precooling components, molecular sieves, air boosters, expanders, plate-fin heat exchangers, coiled heat exchangers, separation tanks, distillation towers, subcoolers, ultra-high pressure oxygen pumps and ultra-high pressure nitrogen pumps; The outlet of the air filter is connected to the inlet of the air compressor, and the air precooling component is connected to the air compressor and precools the compressed air output by the air compressor and then outputs it to the molecular sieve; The molecular sieve purifies the compressed air and outputs the compressed air to the air booster and the plate-fin heat exchanger. The air booster divides the boosted air into two streams, one of which is delivered to the plate-fin heat exchanger and then to the expansion end of the expander, and the other is delivered to the boosting end of the expander and then to the coil heat exchanger. The air delivered to the coil heat exchanger is further divided into two streams, one of which is delivered to the plate-fin heat exchanger for heat exchange and then to the separation tank, and the other is delivered to the coil heat exchanger and then to the separation tank; After the gas-liquid separation in the separation tank, a part of the air and liquid air enter the lower tower, and another part of the liquid air enters the subcooler and enters the upper tower after cooling and throttling; The oxygen-rich liquid air and lean liquid nitrogen obtained by preliminary distillation of the air in the lower tower are transported to the upper tower through the subcooler, and the pure liquid nitrogen obtained by distillation is divided into two streams, one of which is pressurized by the ultra-high pressure nitrogen pump and transported to the coil-wound heat exchanger to obtain ultra-high pressure nitrogen gas, and the other stream is partially transported to the upper tower through the subcooler and partially output as a liquid nitrogen product; The liquid oxygen obtained at the bottom of the upper tower after the upper tower rectification is pressurized by the ultra-high pressure liquid oxygen pump, and part of it enters the coiled heat exchanger and enters the oxygen network, and part of it is output as a liquid oxygen product; The contaminated nitrogen gas obtained at the upper part of the upper tower and the pure nitrogen gas obtained at the top of the upper tower are reheated by the subcooler and the plate-fin heat exchanger, and then partly transported to the heater of the molecular sieve and partly transported to the air precooling component.

2. The low energy consumption ultra-high pressure air separation oxygen and nitrogen production system according to claim 1 is characterized in that: The molecular sieves are arranged in two groups in parallel, one of the two groups of molecular sieves is in the molecular sieve purification process, and the other group is in the regeneration process, and the two groups of molecular sieves are used alternately.

3. The low energy consumption ultra-high pressure air separation oxygen and nitrogen production system according to claim 1, characterized in that: The plate-fin heat exchanger receives two streams of air before and after the air supercharger, respectively. The air before the supercharger is transported to the separation tank after heat exchange by the plate-fin heat exchanger, and the air after the supercharger is transported to the expansion end of the expander after heat exchange by the plate-fin heat exchanger. The plate-fin heat exchanger also receives a stream of air after heat exchange in the coil-wound heat exchanger, and delivers the air to the separation tank after heat exchange in the plate-fin heat exchanger; The plate-fin heat exchanger receives the dirty nitrogen gas output from the upper part of the upper tower after heat exchange in the subcooler, and a part of it is output to the water cooling tower of the air precooling component after heat exchange in the plate-fin heat exchanger, and a part of it is output as regenerated dirty nitrogen gas. It also receives the pure nitrogen gas output from the top of the upper tower after heat exchange in the subcooler, and a part of it is output as normal pressure nitrogen after heat exchange in the plate-fin heat exchanger, and a part of it is output to the water cooling tower of the air precooling component.

4. The low energy consumption ultra-high pressure air separation oxygen and nitrogen production system according to claim 3 is characterized in that: The coiled heat exchanger receives the air pressurized by the booster end of the expander and divides it into two streams, one of which is transported to the plate-fin heat exchanger for heat exchange and then transported to the separation tank, and the other is output from the coiled heat exchanger and then transported to the separation tank; The coiled heat exchanger also receives liquid oxygen output from the bottom of the upper tower and compressed by the ultra-high pressure liquid oxygen pump, and outputs ultra-high pressure oxygen after heat exchange in the coiled heat exchanger; The coiled-tube heat exchanger also receives liquid nitrogen extracted from the top of the lower tower and compressed by the ultra-high pressure nitrogen pump, and outputs the liquid nitrogen as ultra-high pressure nitrogen gas after heat exchange in the coiled-tube heat exchanger.

5. The low energy consumption ultra-high pressure air separation oxygen and nitrogen production system according to claim 1, characterized in that: The air precooling component includes an air cooling tower, a refrigerator and a water cooling tower. The air pressurized by the air compressor is transported to the air cooling tower. The water in the water cooling tower is frozen by the refrigerator and then transported to the air cooling tower. The air in the air cooling tower passes through the frozen water from bottom to top and is output to the molecular sieve.

6. The low energy consumption ultra-high pressure air separation oxygen and nitrogen production system according to claim 4, characterized in that: The flow ratio of the two air streams before and after the air booster, the flow ratio of the two air streams flowing to the plate-fin heat exchanger and the expander respectively, and the flow ratio of the two air streams separated in the coil heat exchanger are adjusted according to the purity, pressure and process conditions of the oxygen and nitrogen to be prepared.

7. A low-energy consumption ultra-high pressure air separation oxygen and nitrogen production method, applied to the low-energy consumption ultra-high pressure air separation oxygen and nitrogen production system as described in any one of claims 1 to 6, characterized in that: include: The raw air is filtered through an air filter and then input into an air compressor for pressurization; The pressurized air is transported to the air pre-cooling component for cooling and cleaning, and then input into the molecular sieve for purification; The purified air is divided into two streams, one is sent to the plate-fin heat exchanger for heat exchange and then output to the separation tank, and the other is sent to the air booster for pressurization; The air pressurized by the air compressor is divided into two streams, one stream is delivered to the plate-fin heat exchanger for heat exchange, then delivered to the expansion end of the expander, and then output to the separation tank, and the other stream is delivered to the boosting end of the expander for pressurization, then output to the coil heat exchanger; The air output to the coiled heat exchanger is divided into two streams, one stream is delivered to the plate-fin heat exchanger for heat exchange and then delivered to the separation tank, and the other stream is delivered to the separation tank after outputting the coiled heat exchanger; After the gas-liquid separation in the separation tank, a part of the air and liquid air enter the lower tower, and the other part of the liquid air is cooled and throttled by the subcooler and then transported to the upper tower; The oxygen-rich liquid air and lean liquid nitrogen obtained by preliminary distillation of the air in the lower tower are transported to the upper tower through the subcooler, and the pure liquid nitrogen obtained by distillation is divided into two streams, one of which is pressurized by the ultra-high pressure nitrogen pump and transported to the coil-wound heat exchanger to obtain ultra-high pressure nitrogen gas, and the other stream is partially transported to the upper tower through the subcooler and partially output as a liquid nitrogen product; The liquid oxygen obtained at the bottom of the upper tower after the upper tower rectification is pressurized by the ultra-high pressure liquid oxygen pump, and part of it enters the coiled heat exchanger and enters the oxygen network, and part of it is output as a liquid oxygen product; The contaminated nitrogen gas obtained at the upper part of the upper tower and the pure nitrogen gas obtained at the top of the upper tower are reheated by the subcooler and the plate-fin heat exchanger, and then partly transported to the heater of the molecular sieve and partly transported to the air precooling component.

8. The method for producing oxygen and nitrogen by ultra-high pressure air separation with low energy consumption according to claim 7, characterized in that: Two groups of molecular sieves are arranged in parallel, one group is in the molecular sieve purification process, and the other group is in the regeneration process, and the two groups of molecular sieves are used alternately.

9. The method for producing oxygen and nitrogen by ultra-high pressure air separation with low energy consumption according to claim 7, characterized in that: The plate-fin heat exchanger receives the dirty nitrogen gas output from the upper part of the upper tower and cooled and throttled by the subcooler, and after heat exchange by the plate-fin heat exchanger, a part of it is output to the water cooling tower of the air precooling component, and a part of it enters the electric heater for heating as a regeneration gas source, and also receives the pure nitrogen gas output from the top of the upper tower and cooled and throttled by the subcooler, and after heat exchange by the plate-fin heat exchanger, a part of it is output as a product and a part of it is output to the water cooling tower of the air precooling component; The coiled tube heat exchanger receives liquid oxygen output from the bottom of the upper tower and compressed by the ultra-high pressure liquid oxygen pump, and outputs it as ultra-high pressure oxygen after heat exchange in the coiled tube heat exchanger, and also receives liquid nitrogen extracted from the top of the lower tower and compressed by the ultra-high pressure nitrogen pump, and outputs it as ultra-high pressure nitrogen after heat exchange in the coiled tube heat exchanger.

10. The method for producing oxygen and nitrogen by ultra-high pressure air separation with low energy consumption according to claim 7, characterized in that: The flow ratio of the two air streams before and after the air booster, the flow ratio of the two air streams flowing to the plate-fin heat exchanger and the expander respectively, and the flow ratio of the two air streams separated in the coil heat exchanger are adjusted according to the purity, pressure and process conditions of the oxygen and nitrogen to be prepared.

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