Air separation device adopting nitrogen circulation and oxygen internal compression mode

Abstract

The utility model provides an air separation device adopting nitrogen circulation and oxygen internal compression modes, which comprises an air filtering system, a raw material air turbine compressor, an air pre-cooling system, an air purification system, a main heat exchanger, a nitrogen circulation compressor system, a high-low temperature expansion system, a rectifying tower and a liquid air and liquid oxygen subcooler, the rectifying tower comprises an upper tower, a main condensation evaporator and a lower tower, a liquid oxygen pipeline is arranged after the main condensation evaporator enters the liquid air and liquid oxygen subcooler, a liquid oxygen branch pipeline is arranged on the liquid oxygen pipeline, a liquid oxygen pump is arranged on the liquid oxygen branch pipeline, and the liquid oxygen is output after being pressurized by the liquid oxygen pump and subjected to heat exchange through a main heat exchanger. Output from the top of the upper tower enters the liquid air and liquid oxygen subcooler and then is subjected to heat exchange output through the main heat exchanger, a nitrogen circulating pipeline is arranged on the low-pressure nitrogen pipeline, a high-pressure nitrogen circulating pipeline is additionally arranged on the nitrogen circulating pipeline, and the high-pressure nitrogen circulating machine is pressurized to enter the main heat exchanger to be subjected to heat exchange cooling with liquid oxygen and then enters the lower tower to be rectified after being throttled. The whole set of energy consumption of air separation equipment is reduced, and cold source recycling of liquid oxygen vaporization is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to air separation technical field, concretely relates to a kind of air separation device using nitrogen cycle and oxygen internal compression mode. BACKGROUND

[0002] Air separation equipment, simply speaking, is a set of industrial equipment for separating each component in air, producing oxygen, nitrogen, liquid oxygen and liquid nitrogen. It includes air filtration system, air compressor system, air precooling system, air purification system, circulating compressor system, high and low temperature expansion system, heat exchange system and air rectification system.

[0003] At present, the product oxygen discharged from the air separation device with conventional structure is low pressure, and the low pressure oxygen is compressed by compressor, pressurized and then sent to users through pipeline, or the product liquid oxygen is compressed by liquid oxygen pump, pressurized, vaporized by special vaporizer and then sent to users through pipeline. However, the energy consumption of the air separation device needs to be reduced, and the conventional structure air separation device lacks recycling of cold source. Therefore, how to reduce the overall energy consumption of air separation equipment and recycling of cold source for vaporization of liquid oxygen by vaporizer becomes a research direction. SUMMARY

[0004] The utility model aims at solving the above problems and provides an air separation device using nitrogen cycle and oxygen internal compression mode, which has the characteristics of reducing the overall energy consumption of air separation equipment and recycling of cold source.

[0005] The utility model discloses a kind of air separation devices using nitrogen cycle and oxygen internal compression mode, including air filtration system, raw material air turbine compressor, air precooling system, air purification system, main heat exchanger, nitrogen cycle compressor system, high-low temperature expansion system, rectifying tower and liquid air liquid oxygen subcooler, the air filtration system is pressurized to reach air precooling system by raw material air turbine compressor, the air precooling system is connected with air purification system, the rectifying tower includes upper tower, main condenser evaporator and lower tower, the air purification system output enters main heat exchanger and reaches lower tower, the main condenser evaporator is provided with liquid oxygen pipeline after entering liquid air liquid oxygen subcooler, liquid oxygen branch pipeline is provided on the liquid oxygen pipeline, liquid oxygen pump is provided on the liquid oxygen branch pipeline, the liquid oxygen pump is pressurized after heat exchange by main heat exchanger and is output and is provided with medium-pressure oxygen pipeline, the upper tower top is pressurized after heat exchange by main heat exchanger and is output and is provided with low-pressure nitrogen pipeline after entering liquid air liquid oxygen subcooler, nitrogen circulation pipeline is provided on the low-pressure nitrogen pipeline, the nitrogen cycle compressor system and high-low temperature expansion system are arranged on nitrogen circulation pipeline, the high-low temperature expansion system output enters lower tower, high-pressure nitrogen circulation path is additionally provided on the nitrogen circulation pipeline, high-pressure nitrogen circulation machine is provided on the high-pressure nitrogen circulation path, the high-pressure nitrogen circulation machine is pressurized and enters main heat exchanger and is cooled after heat exchange with the liquid oxygen pipeline, and is throttled into lower tower and participates in rectification after entering.

[0006] As preferred in the utility model, the air filtration system is a self-cleaning air filter.

[0007] As preferred in the utility model, the air precooling system is provided with air cooling tower, precooling unit, water pump and water cooling tower, the air cooling tower is connected with the water pump, the precooling unit and the water cooling tower respectively, the precooling unit is connected with the water cooling tower, and the water cooling tower is connected with the water pump.

[0008] As preferred in the utility model, the air purification system is provided with molecular sieve purifier I and molecular sieve purifier II, the molecular sieve purifier II is connected with the molecular sieve purifier I, the molecular sieve purifier I and the molecular sieve purifier II are provided with silencer, and the molecular sieve purifier I and the molecular sieve purifier II are provided with electric heater.

[0009] As preferred in the utility model, the nitrogen cycle compressor system includes raw material nitrogen turbine compressor and circulating nitrogen turbine compressor, the cooler I is arranged between the raw material nitrogen turbine compressor and the circulating nitrogen turbine compressor, and the cooler II is arranged in connection with the circulating nitrogen turbine compressor.

[0010] As the high and low temperature expansion system of the utility model preferably, the high temperature expander and the low temperature expander are set up on the high temperature expander and the low temperature expander, the high temperature expander booster end is connected with the low temperature expander booster end, the cooler III is set up between the high temperature expander booster end and the low temperature expander booster end, the cooler IV is connected and set up on the low temperature expander booster end, the cooler IV cooling enters the main heat exchanger heat exchange and connects in the high pressure nitrogen gas circulation path and enters the lower tower, the cooler IV cooling enters the main heat exchanger heat exchange and connects in the low temperature expander, the high temperature expander is connected with the high pressure nitrogen gas circulation path, the low temperature expander output enters the main heat exchanger and reaches the nitrogen gas circulation pipeline, the main condenser and the upper tower are set up with the backflow pipeline, the backflow pipeline is supercooled through the liquid air liquid oxygen supercooler, the low temperature expander output enters the liquid air liquid oxygen supercooler and connects to the backflow pipeline.

[0011] As the utility model preferably, the liquid nitrogen pipeline is set up on the backflow pipeline, and the automatic stop valve I is set up on the liquid nitrogen pipeline.

[0012] As the utility model preferably, the automatic stop valve II is set up on the liquid oxygen pipeline.

[0013] The utility model has the advantages that: the utility model adopts the technology of nitrogen circulation and oxygen internal compression, increases the liquid oxygen branch pipeline on the liquid oxygen pipeline, uses the liquid oxygen pump on the liquid oxygen branch pipeline to pressurize and then enters the main heat exchanger to exchange heat, and then outputs the medium pressure oxygen through the medium pressure oxygen pipeline to the user, the nitrogen circulation pipeline uses the nitrogen circulation compressor system to pressurize, because the high pressure nitrogen circulation path is additionally arranged on the nitrogen circulation pipeline, enters the main heat exchanger to exchange heat with liquid oxygen after pressurizing by the high pressure nitrogen circulation machine, and then enters the lower tower of the rectifying tower to participate in rectification after throttling, through the above pipeline transformation and equipment increase, uses the liquid oxygen pump and the high pressure nitrogen circulation machine, can reduce the energy consumption of the air separation equipment, and simultaneously realizes the cold source recycling of liquid oxygen vaporization. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is the principle schematic view of the utility model;

[0015] In the figure: 1, raw material air turbine compressor; 2, main heat exchanger; 3, rectification tower; 4, liquid air liquid oxygen subcooler; 5, upper tower; 6, main condensing evaporator; 7, lower tower; 8, liquid oxygen pipeline; 9, liquid oxygen branch pipeline; 10, liquid oxygen pump; 11, medium pressure oxygen pipeline; 12, low pressure nitrogen pipeline; 13, nitrogen circulating pipeline; 14, high pressure nitrogen circulating pipeline; 15, high pressure nitrogen circulating machine; 16, self-cleaning air filter; 17, air cooling tower; 18, pre-cooling unit; 19, water pump; 20, water cooling tower; 21, molecular sieve purifier I; 22, molecular sieve purifier II; 23, silencer; 24, electric heater; 25, raw material nitrogen turbine compressor; 26, circulating nitrogen turbine compressor; 27, cooler I; 28, cooler II; 29, high temperature expander; 30, low temperature expander; 31, high temperature expander pressurizing end; 32, low temperature expander pressurizing end; 33, cooler III; 34, cooler IV; 35, return pipeline; 36, liquid nitrogen pipeline; 37, automatic stop valve I; 38, automatic stop valve II. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0017] Please refer to Figure 1As shown, an air separation device adopting nitrogen cycle and oxygen internal compression mode, comprising an air filtering system, a raw material air turbine compressor 1, an air precooling system, an air purification system, a main heat exchanger 2, a nitrogen cycle compressor system, a high and low temperature expansion system, a rectification tower 3 and a liquid air liquid oxygen subcooler 4, the air filtering system is pressurized by the raw material air turbine compressor 1 to reach the air precooling system, the air precooling system is connected with the air purification system, the rectification tower 3 comprises an upper tower 5, a main condensation evaporator 6 and a lower tower 7, the air purification system outputs into the main heat exchanger 2 to reach the lower tower 7, the main condensation evaporator 6 is provided with a liquid oxygen pipeline 8 after entering the liquid air liquid oxygen subcooler 4, the liquid oxygen pipeline 8 is provided with a liquid oxygen branch pipeline 9, the liquid oxygen branch pipeline 9 is provided with a liquid oxygen pump 10, the liquid oxygen pump 10 is pressurized and outputs through the main heat exchanger 2 after heat exchange, and is provided with a medium pressure oxygen pipeline 11, the upper tower 5 is provided with a low pressure nitrogen pipeline 12 after heat exchange through the main heat exchanger 2 after outputting into the liquid air liquid oxygen subcooler 4 at the top, the low pressure nitrogen pipeline 12 is provided with a nitrogen cycle pipeline 13, the nitrogen cycle compressor system and the high and low temperature expansion system are arranged on the nitrogen cycle pipeline 13, the high and low temperature expansion system outputs into the lower tower 7, the nitrogen cycle pipeline 13 is additionally provided with a high pressure nitrogen cycle pipeline 14, the high pressure nitrogen cycle pipeline 14 is provided with a high pressure nitrogen cycle machine 15, the high pressure nitrogen cycle machine 15 is pressurized, enters the main heat exchanger 2, exchanges heat with the liquid oxygen of the liquid oxygen pipeline 8, is throttled into the lower tower 7 after cooling, and participates in rectification.

[0018] In the embodiment, the raw material is air, is introduced into the raw material air turbine compressor 1 for compression and pressurization, is sent into the air precooling system for precooling, is removed from the purification system after removing carbon dioxide, water and hydrocarbon impurities, is introduced into the main heat exchanger 2 for heat exchange and cooling, and is introduced into the lower tower 7 for rectification and purification; the technology of nitrogen cycle and oxygen internal compression is adopted, the liquid oxygen pipeline is arranged after the main condensation evaporator 6 enters the liquid air liquid oxygen subcooler, the liquid oxygen branch pipeline is arranged on the liquid oxygen pipeline, the liquid oxygen pump 10 on the liquid oxygen branch pipeline is pressurized, reenters the main heat exchanger 2 for heat exchange, outputs medium pressure oxygen through the medium pressure oxygen pipeline 11, and sends the medium pressure oxygen to a user, the medium pressure oxygen pipeline 11 is used for outputting medium pressure oxygen, the low pressure nitrogen pipeline 12 is arranged on the upper tower 5 after heat exchange through the main heat exchanger 2 after outputting into the liquid air liquid oxygen subcooler 4 at the top, the nitrogen cycle pipeline 13 is pressurized by the nitrogen cycle compressor system, the high pressure nitrogen cycle pipeline 14 is additionally arranged on the nitrogen cycle pipeline 13, the high pressure nitrogen cycle machine 15 is pressurized, enters the main heat exchanger 2, exchanges heat with the liquid oxygen of the liquid oxygen pipeline 8, is throttled into the lower tower 7 of the rectification tower 3 after cooling, and participates in rectification, through the transformation of the pipelines and the increase of the equipment, the liquid oxygen pump 10 and the high pressure nitrogen cycle machine 15 are used, the main heat exchanger 2 is used at the same time, a plurality of pipelines are simultaneously processed, the efficiency of heat exchange work is further improved, the effective use of energy is ensured, the energy consumption of the air separation device is reduced, and the cold source recycling of liquid oxygen vaporization is achieved.

[0019] Specifically, the high-low temperature expansion system can provide cold energy for the pipeline of the air separation device, so that a better refrigeration effect is achieved, and the cooperation of the high-low temperature expansion system and the nitrogen circulating compressor system is more obvious, and energy recycling is achieved.

[0020] As a technical optimization scheme of the utility model, as shown in Figure 1 The air filter system is a self-cleaning air filter 16.

[0021] In this embodiment, the self-cleaning air filter 16 has a self-cleaning function, and the use effect is better.

[0022] As a technical optimization scheme of the utility model, as shown in Figure 1 The air pre-cooling system is provided with an air cooling tower 17, a pre-cooling unit 18, a water pump 19 and a water cooling tower 20, the air cooling tower 17 is connected with the water pump 19, the pre-cooling unit 18 and the water cooling tower 20, the pre-cooling unit 18 and the water cooling tower 20 are connected, and the water cooling tower 20 is connected with the water pump 19.

[0023] In this embodiment, the air pre-cooling system is used to pre-cool and wash the raw material air before the adsorption of the purification system, the water pump 19 is used for water pressurization, and the water cooling tower 20 is used for water cooling. With this structure, the pre-cooling effect is better, and the basic pre-cooling function is more stable.

[0024] As a technical optimization scheme of the utility model, as shown in Figure 1 The air purification system is provided with a molecular sieve purifier I 21 and a molecular sieve purifier II 22, the molecular sieve purifier II 22 is connected with the molecular sieve purifier I 21, the molecular sieve purifier I 21 and the molecular sieve purifier II 22 are provided with a silencer 23, and the molecular sieve purifier I 21 and the molecular sieve purifier II 22 are provided with an electric heater 24.

[0025] In this embodiment, the above structure can remove carbon dioxide, moisture and hydrocarbons to 1PPm, and can also reduce the regeneration temperature and regeneration energy, improve the service life, and reduce the noise of the silencer 23.

[0026] As a technical optimization scheme of the utility model, as shown in Figure 1 The nitrogen circulating compressor system comprises a raw material nitrogen turbine compressor 25 and a circulating nitrogen turbine compressor 26, a cooler I 27 is arranged between the raw material nitrogen turbine compressor 25 and the circulating nitrogen turbine compressor 26, and a cooler II 28 is arranged in connection with the circulating nitrogen turbine compressor 26.

[0027] In this embodiment, this structure achieves a better circulating pressurization and cooling effect.

[0028] As a technical optimization solution of this utility model, such as Figure 1 As shown, the high and low temperature expansion system includes a high temperature expander 29 and a low temperature expander 30. The high temperature expander 29 is equipped with a high temperature expander pressurization end 31, and the low temperature expander 30 is equipped with a low temperature expander pressurization end 32. The high temperature expander pressurization end 31 and the low temperature expander pressurization end 32 are connected. A cooler III 33 is installed between the high temperature expander pressurization end 31 and the low temperature expander pressurization end 32. A cooler IV 34 is connected to the pressurization end of the low temperature expander 30, and the cooler IV 34 cools the fluid entering the main heat exchanger. After heat exchange, the gas enters the lower tower via the high-pressure nitrogen circulation line 14. After cooling by the cooler IV34, the gas enters the main heat exchanger 2 and is then connected to the cryogenic expander 30. The high-temperature expander 29 is connected to the high-pressure nitrogen circulation line 14. The output of the cryogenic expander 30 enters the main heat exchanger 2 and then reaches the nitrogen circulation line 13. A reflux line 35 is provided between the main condenser evaporator 6 and the upper tower 5. The reflux line 35 is subcooled by the liquid air-liquid oxygen subcooler 4. The output of the cryogenic expander 30 enters the liquid air-liquid oxygen subcooler 4 and is then connected to the reflux line 35.

[0029] In this embodiment, the high-temperature expander pressurization end 31 can adjust the pressurization output of the high-temperature expander 29, and the low-temperature expander pressurization end 32 can adjust the pressurization output of the low-temperature expander 30. Coolers III 33 and IV 34 can be used for cooling during pressurization output. After cooling by cooler IV 34, the gas enters the main heat exchanger 2 for heat exchange and is connected to the high-pressure nitrogen circulation path 14 to enter the lower tower 7. A return pipeline 35 is provided between the main condenser evaporator 6 and the upper tower 5. The return pipeline 35 is subcooled by the liquid air-liquid oxygen subcooler 4. The output of the low-temperature expander 30 enters the liquid air-liquid oxygen subcooler 4 and is connected to the return pipeline 35. By adopting a high- and low-temperature expansion system and a circulating compressor system, the cooling cycle of each pipeline can be performed, achieving a more obvious effect and realizing energy recycling.

[0030] As a technical optimization solution of this utility model, such as Figure 1 As shown, a liquid nitrogen line 36 is installed on the return line 35, and an automatic shut-off valve I37 is installed on the liquid nitrogen line 36.

[0031] In this embodiment, the automatic shut-off valve I37 can control the discharge rate of the liquid nitrogen pipeline 36.

[0032] As a technical optimization solution of this utility model, such as Figure 1 As shown, an automatic shut-off valve II38 is installed on the liquid oxygen pipeline 8.

[0033] In this embodiment, the automatic shut-off valve II38 can control the discharge rate on the liquid oxygen pipeline 8.

[0034] It will be obvious to a person skilled in the art that the application is not limited to the details of the above-described exemplary embodiments, but that the application can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. The embodiments should, therefore, be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalents of the claims are therefore intended to be embraced therein. Any reference signs in the claims should not be construed as limiting the claims concerned.

[0035] Furthermore, it should be understood that although the present specification is described in terms of exemplary embodiments, not every implementation embodies only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other implementations that those skilled in the art can understand.

Claims

1. An air separation device using nitrogen cycle and oxygen internal compression mode, comprising an air filtering system, a raw material air turbine compressor (1), an air precooling system, an air purification system, a main heat exchanger (2), a nitrogen cycle compressor system, a high and low temperature expansion system, a rectification tower (3) and a liquid air liquid oxygen supercooler (4), the air filtering system reaches the air precooling system through the raw material air turbine compressor (1) for pressurization, and the air precooling system is connected with the air purification system, characterized in that: The rectification tower (3) comprises an upper tower (5), a main condensation evaporator (6) and a lower tower (7), the air purification system outputs into the main heat exchanger (2) to the lower tower (7), the main condensation evaporator (6) is provided with a liquid oxygen pipeline (8) after entering the liquid air liquid oxygen supercooler (4), the liquid oxygen pipeline (8) is provided with a liquid oxygen branch pipeline (9), the liquid oxygen branch pipeline (9) is provided with a liquid oxygen pump (10), the liquid oxygen pump (10) is provided with a medium-pressure oxygen pipeline (11) after heat exchange through the main heat exchanger (2) after being pressurized, the upper tower (5) is provided with a low-pressure nitrogen pipeline (12) after heat exchange through the main heat exchanger (2) after outputting into the liquid air liquid oxygen supercooler (4), the low-pressure nitrogen pipeline (12) is provided with a nitrogen circulation pipeline (13), the nitrogen circulation compressor system and the high-low temperature expansion system are arranged on the nitrogen circulation pipeline (13), the high-low temperature expansion system outputs into the lower tower (7), the nitrogen circulation pipeline (13) is additionally provided with a high-pressure nitrogen circulation pipeline (14), the high-pressure nitrogen circulation pipeline (14) is provided with a high-pressure nitrogen circulation machine (15), the high-pressure nitrogen circulation machine (15) is pressurized into the main heat exchanger (2) and is cooled through heat exchange with the liquid oxygen of the liquid oxygen pipeline (8), and then is throttled into the lower tower (7) to participate in rectification.

2. The air separation device of claim 1, wherein: The air filter system is a self-cleaning air filter (16).

3. The air separation unit of claim 1, wherein: The air precooling system is provided with an air cooling tower (17), a precooling unit (18), a water pump (19) and a water cooling tower (20), the air cooling tower (17) is connected with the water pump (19), the precooling unit (18) and the water cooling tower (20) respectively, the precooling unit (18) and the water cooling tower (20) are connected, and the water cooling tower (20) is connected with the water pump (19).

4. The air separation unit of claim 1, wherein: The air purification system is provided with a molecular sieve purifier I (21) and a molecular sieve purifier II (22), the molecular sieve purifier II (22) is connected with the molecular sieve purifier I (21), the molecular sieve purifier I (21) and the molecular sieve purifier II (22) are provided with a silencer (23) connected therewith, and the molecular sieve purifier I (21) and the molecular sieve purifier II (22) are provided with an electric heater (24) connected therewith.

5. The air separation unit of claim 1, wherein: The nitrogen circulation compressor system comprises a raw material nitrogen turbine compressor (25) and a circulating nitrogen turbine compressor (26), a cooler I (27) is arranged between the raw material nitrogen turbine compressor (25) and the circulating nitrogen turbine compressor (26), and the circulating nitrogen turbine compressor (26) is provided with a cooler II (28).

6. The air separation unit of claim 1, wherein: The high-low temperature expansion system comprises a high temperature expander (29) and a low temperature expander (30), the high temperature expander (29) is provided with a high temperature expander booster end (31), the low temperature expander (30) is provided with a low temperature expander booster end (32), the high temperature expander booster end (31) is connected with the low temperature expander booster end (32), a cooler III (33) is arranged between the high temperature expander booster end (31) and the low temperature expander booster end (32), the low temperature expander booster end (32) is connected with a cooler IV (34), the cooler IV (34) is cooled after heat exchange in a main heat exchanger (2) and connected with a high pressure nitrogen circulation loop (14) to enter a lower tower (7), the cooler IV (34) is cooled after heat exchange in the main heat exchanger (2) and connected with the low temperature expander (30), the high temperature expander (29) is connected with the high pressure nitrogen circulation loop (14), the low temperature expander (30) is connected with a nitrogen circulation loop (13) after outputting into the main heat exchanger (2), a backflow loop (35) is arranged between the main condenser evaporator (6) and the upper tower (5), the backflow loop (35) is supercooled through a liquid air liquid oxygen supercooler (4), the low temperature expander (30) is connected with the backflow loop (35) after outputting into the liquid air liquid oxygen supercooler (4).

7. The air separation unit of claim 6, wherein: An automatic stop valve I (37) is arranged on the liquid nitrogen loop (36).

8. The air separation unit of claim 1, wherein: An automatic stop valve II (38) is arranged on the liquid oxygen loop (8).

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