A tubular oxygen-nitrogen air separation plant with isobaric separation

Abstract

The utility model relates to the field of tubular oxygen nitrogen air separation device, especially is concerned on a kind of tubular oxygen nitrogen air separation device of isobaric separation.It is a kind of tubular oxygen nitrogen air separation device of isobaric separation, including air purification system, the air purification system is equipped with multiple purification devices, to carry out pre-purification treatment to air, remove carbon dioxide and solid impurities in air, obtain pre-purification air;Precooling system, the precooling system is equipped with cold exchanger to cool the pre-purification air;Rectification system, the rectification system includes rectification device to isobaric separation nitrogen and oxygen;Through the above technical scheme, the core system of the present application constructs isobaric separation infrastructure in coordination.Multiple purification device setting solves the problem that traditional single purification cannot remove impurities simultaneously, and the directional cooling of cold exchanger provides a stable low-temperature environment for rectification, which is suitable for gas separation requirements of different scale industrial scenarios.

Description

Technical Field

[0001] This utility model relates to the field of tubular oxygen-nitrogen air separation devices, and in particular to a tubular oxygen-nitrogen air separation device with isobaric separation. Background Technology

[0002] Air separation equipment is a core piece of equipment in industries such as steel, metallurgy, and coal chemicals, and its capacity and energy efficiency directly affect industrial production efficiency. With the upgrading of the national economy, the market demand for large-scale, low-energy oxygen generators has surged. However, the refrigeration process has always relied on thermodynamic Carnot reverse cycle analysis, which makes it difficult to intuitively explain the cycle mechanism. This limits the improvement of cold energy utilization efficiency, and the adaptability and safety stability of centralized gas supply still need to be optimized. Traditional air separation equipment suffers from multiple technical limitations: Theoretically, it relies on the Carnot reverse cycle's coefficient of performance to measure economic efficiency, which fails to clearly explain the cold energy transfer path, resulting in a bottleneck in improving actual cycle efficiency; in terms of safety, carbon dioxide in the air easily forms dry ice that blocks pipelines, and acetylene accumulation in liquid oxygen can easily cause explosions, and existing purification systems are mostly single-filter systems, making it difficult to achieve deep removal of impurities; in terms of efficiency, condensers and evaporators are mostly of ordinary structure, resulting in low heat transfer efficiency between liquid oxygen boiling inside the tubes and gas nitrogen condensation between the tubes, excessively high liquid fraction in the upper column, and a large gas-liquid temperature difference, which fails to fully release the potential distillation capacity, and the synergy between refrigeration and separation under the entire low-pressure process is insufficient, restricting overall energy efficiency. The specific shortcomings of existing technologies further highlight the necessity for improvement: First, insufficient utilization of cold energy, lack of coordination between the cold replenishment system and the pre-cooling system, and failure to achieve cascade energy recovery, resulting in cold energy waste; second, poor pressure stability, with the air compressor exhaust pressure not matching the isobaric requirements of subsequent systems, easily causing airflow fluctuations and affecting separation purity; third, low product delivery adaptability, unable to accommodate both liquid / gaseous product output and different production capacity requirements, and a disconnect between small and large equipment; these problems make it difficult for traditional air separation equipment to meet the current needs of high-quality industrial development, and new technological solutions are urgently needed to break through the bottlenecks. Utility Model Content

[0003] To address the aforementioned technical problems, this application provides a tubular oxygen-nitrogen air separation device with isobaric separation.

[0004] The tubular oxygen-nitrogen-air separation device with isobaric separation provided in this application adopts the following technical solution: A tubular oxygen and nitrogen air separation device with isobaric separation includes: An air purification system, wherein the air purification system is equipped with multiple purification devices to pre-purify the air, remove carbon dioxide and solid impurities from the air, and obtain pre-purified air; A precooling system, wherein the precooling system is equipped with a cold exchanger to cool the pre-purified air; A distillation system, the distillation system comprising a distillation unit for isobaric separation of nitrogen and oxygen; Through the above technical solution, this application constructs an isobaric separation infrastructure with three core systems working in synergy: air purification, pre-cooling, and distillation. The air purification system uses multiple purifying devices in tandem to specifically remove carbon dioxide and solid impurities from the air, avoiding the limitations of single-system purification. The pre-cooling system, centered on a cold exchanger, directionally cools the pre-purified air, creating low-temperature conditions for distillation. The distillation system, relying on a dedicated distillation unit, achieves efficient separation of nitrogen and oxygen under isobaric conditions. These three systems are interconnected through fluid pipelines, forming a complete process from air pretreatment to gas separation, laying the architectural foundation for future functional expansion. This solution overcomes the fragmentation problem of traditional air separation equipment systems, ensuring focused functionality and smooth collaboration through a modular architecture design. The multiple purification devices solve the problem of simultaneous impurity removal inherent in traditional single-system purification. The directional cooling of the cold exchanger provides a stable low-temperature environment for distillation, while the isobaric separation architecture avoids the impact of pressure fluctuations on separation purity. Overall, it provides fundamental support for energy saving and safe operation of the equipment, adapting to the gas separation needs of industrial scenarios of different scales.

[0005] Furthermore, the isobaric separation tubular oxygen and nitrogen air separator also includes a cold replenishment system, which comprises: A refrigerant tank, wherein the refrigerant tank is located at one end of the distillation system and has a receiving cavity for containing liquid refrigerant; A hydraulic pump, wherein the liquid pump is located between the refrigerant tank and the precooling system, to pump liquid refrigerant into the precooling system to heat it into a superheated refrigerant flow; An expander connected to the superheated refrigerant flow to expand and cool the superheated refrigerant flow; A cold regenerator is connected to the expander to cool the superheated refrigerant stream after expansion and to replenish the cooling of the distillation system.

[0006] Through the above technical solution, this application clarifies the component composition and connection relationship of the cold replenishment system. The refrigerant tank is located at one end of the distillation system, which can shorten the refrigerant delivery path and reduce cold energy loss. The hydraulic pump connects the refrigerant tank and the pre-cooling system, which can accurately pump liquid refrigerant to the pre-cooling system and use the waste heat of the pre-cooling system to heat it into a superheated refrigerant flow. The expander is connected to the superheated refrigerant flow and achieves rapid cooling of the refrigerant through expansion. The cold regenerator further cools the cooled refrigerant and directs it to replenish the cold of the distillation system, solving the problems of dispersed components and large cold energy loss in traditional cold replenishment systems. The refrigerant tank is close to the distillation system to shorten the delivery distance. The accurate delivery of the hydraulic pump and the utilization of waste heat from the pre-cooling system reduce the energy consumption for refrigerant heating. The synergy between the expander and the cold regenerator ensures that the replenishment temperature is stable and adaptable to the distillation requirements, making the cold supply of the distillation system sufficient and controllable, directly supporting the goal of 30% energy saving of the overall equipment, while improving the stability of distillation separation.

[0007] Furthermore, the air purification system includes: An air compressor that drives an airflow; An air purifier, wherein the air purifier is connected to the output end of the air compressor to purify the airflow into a pre-purified airflow; A carbon dioxide adsorber is provided at the output end of the air purifier to remove carbon dioxide from the pre-purified airflow. An expansion filter is provided at the output end of the carbon dioxide adsorber to remove impurities from the pre-purified airflow after adsorption treatment by the carbon dioxide adsorber.

[0008] Through the above technical solution, this application refines the component sequence and function of the air purification system. The air compressor drives the air to form a stable airflow; the air purifier first performs preliminary purification on the airflow, removing most of the impurities to form a pre-purified airflow; the carbon dioxide adsorber is connected to the output end of the air purifier to specifically adsorb carbon dioxide in the pre-purified airflow and prevent it from forming dry ice; the expansion filter is located at the end to further filter residual solid impurities, completely solving the problem of incomplete impurity removal in traditional purification systems.

[0009] Furthermore, the precooling system includes: A cold exchanger, one end of which is equipped with a cold storage unit, and the other end of which is connected to the output of the air purification system to cool the pre-purified air. An automatic valve box is located between the cold exchanger and the cold storage unit to control the airflow direction and flow rate of the pre-purified air.

[0010] Through the above technical solution, this application clarifies the component layout and function of the pre-cooling system. One end of the cold exchanger is connected to the air purification system to receive pre-purified air and perform cooling treatment. The cold storage unit is located at the other end of the cold exchanger, which can store cold energy and maintain cooling stability to avoid temperature fluctuations. The automatic valve box is located between the cold exchanger and the cold storage unit. It can precisely control the airflow direction and flow rate of the pre-purified air through valve adjustment to ensure that the amount of air entering the cold storage unit matches the cooling capacity of the cold exchanger, thus solving the problems of large temperature fluctuations and poor airflow control in traditional pre-cooling systems.

[0011] Furthermore, the distillation system includes: A distillation apparatus, comprising an upper column and a lower column and connected to the precooling system, wherein the lower column precools and separates pre-purified air into an oxygen-rich liquid air stream and a first gaseous nitrogen stream; A condenser-evaporator is disposed between the upper tower and the lower tower and is formed as a long tube. A nitrogen evaporator, which is connected to the upper column to condense the second gaseous nitrogen stream output from the upper column to obtain a second liquid nitrogen stream; A liquid nitrogen subcooler is provided at the output end of the lower column, and the first gaseous nitrogen stream is cooled into a first liquid nitrogen stream and transported to the upper column; A liquid air absorber is provided at the output end of the lower tower to remove carbon dioxide, dry ice, and acetylene from the oxygen-rich liquid air stream; A liquid oxygen absorber is located at the output end of the liquid air absorber and circulates internally to remove acetylene under the drive of a liquid oxygen pump.

[0012] Through the above technical solution, this application elaborates on the component composition and working process of the distillation system. The upper and lower columns of the distillation unit receive pre-cooled air, and the lower column separates it into an oxygen-enriched liquid air stream and a first gaseous nitrogen stream. A condenser-evaporator with a long tubular structure is located between the two columns to increase the heat transfer area and improve the heat transfer efficiency. The nitrogen evaporator condenses the second gaseous nitrogen stream output from the upper column to obtain a second liquid nitrogen stream. The liquid nitrogen subcooler cools the first gaseous nitrogen stream into a first liquid nitrogen stream and delivers it to the upper column. The liquid air absorber removes carbon dioxide, dry ice, and acetylene from the oxygen-enriched liquid air stream, and the liquid oxygen absorber circulates internally under the drive of the liquid oxygen pump to deeply remove residual acetylene from the liquid oxygen, thus solving the problems of low efficiency and high safety risks in traditional distillation systems.

[0013] Furthermore, in the air purification system, the exhaust pressure of the air compressor is adapted to the isobaric separation requirements of the pre-cooling system and the distillation system, ensuring that the airflow maintains stable pressure in each system.

[0014] Through the above technical solution, this application determines the exhaust pressure parameters of the air compressor by accurately calculating the cooling pressure requirements of the pre-cooling system's cold exchanger and the isobaric separation pressure requirements of the upper and lower columns of the distillation system. This ensures that the exhaust pressure meets both the cooling power requirements of the pre-cooling system and matches the isobaric environment of the distillation system, avoiding excessive pressure that increases system load and insufficient airflow power that leads to excessive pressure, thus achieving pressure stability throughout the entire process from air purification to distillation. Furthermore, to address the operational instability caused by pressure imbalance in traditional equipment, the lower and upper columns of the distillation system are thermally coupled through a condenser-evaporator. The oxygen-rich liquid air from the lower column is depressurized by a throttling valve before entering the middle of the upper column, while the first liquid nitrogen is depressurized by a throttling valve before entering the top of the upper column.

[0015] Through the above technical solution, this application designs a thermal coupling and fluid regulation mechanism for a distillation column. The lower and upper columns are thermally coupled through a condenser-evaporator. The heat released by the boiling of liquid oxygen inside the condenser-evaporator tubes and the heat absorbed by the condensation of gaseous nitrogen between the tubes form an energy cycle, improving heat transfer efficiency. Simultaneously, throttling valves are installed on the transport paths of the oxygen-enriched liquid air flow and the first liquid nitrogen flow. The oxygen-enriched liquid air flow is depressurized by the throttling valve before entering the middle of the upper column, while the first liquid nitrogen flow is depressurized by the throttling valve before entering the top of the upper column. By adjusting the reflux ratio and contact state of the two fluids through depressurization, the distillation potential of the upper column is fully activated. This solves the problems of poor synergy and wasted distillation potential in traditional distillation columns.

[0016] In summary, this application includes at least one of the following beneficial technical effects: 1. This application solves the problems of fragmentation and functional disconnect in traditional air separation equipment systems by adopting a modular collaborative architecture of "air purification - pre-cooling - distillation - cold replenishment". The stepped impurity removal design of the air purification system can simultaneously remove carbon dioxide and solid impurities from the air, avoiding pipeline blockage and equipment scaling; the dual absorber and liquid oxygen circulation design of the distillation system can deeply remove dangerous impurities such as acetylene, eliminating the risk of explosion; the precise flow control and cold storage design of the pre-cooling system provide a stable environment for subsequent processes. The orderly connection of each system forms a closed loop, which not only avoids the impact of a single system failure on the whole, but also reduces safety risks from the source and ensures long-term stable operation of the equipment. 2. This application's device achieves a dual breakthrough in energy utilization and separation efficiency. The cold replenishment system reduces cold energy loss and additional energy consumption by shortening the refrigerant delivery path and utilizing pre-cooling waste heat to heat the refrigerant; the thermal coupling design of the distillation system and the long-tube condenser-evaporator enhance energy circulation and heat transfer, fully activating the distillation potential; the compressor discharge pressure adaptation design ensures stable pressure throughout the process, avoiding energy waste. These designs collectively break through the bottleneck of high energy consumption in traditional equipment, improving energy utilization while increasing the purity of oxygen and nitrogen products, achieving both high-efficiency separation and low-consumption operation. 3. The architecture and functional configuration of the device in this application fully consider the diverse needs of industry. The modular structure can be flexibly adjusted according to different production capacity requirements, adapting to gas supply needs in industrial scenarios ranging from small and medium-sized to extra-large. The fluid regulation mechanism and product handling design of the distillation system can meet the output requirements of different gas forms, such as gaseous and liquid. Stable pressure control and efficient impurity removal capabilities make it suitable for fields with stringent gas quality requirements, such as steel and coal chemical industries. Compared to the poor adaptability of traditional equipment, this device better meets the needs of centralized gas supply and differentiated production, enhancing its practical value and potential for widespread application in the industrial field. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a tubular oxygen-nitrogen-air separation device with isobaric separation according to an embodiment of this application; Explanation of reference numerals in the attached diagram: 1. Air purification system; 11. Air compressor; 12. Air purifier; 13. Carbon dioxide adsorber; 14. Expansion filter; 2. Pre-cooling system; 21. Cold exchanger; 22. Automatic valve box; 3. Distillation system; 31. Distillation unit; 32. Condenser evaporator; 33. Nitrogen evaporator; 34. Liquid nitrogen subcooler; 35. Liquid air absorber; 36. Liquid oxygen absorber; 4. Cold replenishment system; 41. Refrigerant tank; 42. Hydraulic pump; 43. Expander; 44. Cold regenerator. Detailed Implementation

[0018] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0019] This application discloses a tubular oxygen-nitrogen-air separation device with isobaric separation.

[0020] Reference Figure 1 A modular, series-connected isobaric tubular oxygen and nitrogen air separation device is described, with an air purification system 1 and a pre-cooling system 2 connected sequentially. The output of the air compressor 11 is directly connected to the inlet of the air purifier 12 via a pipeline. The outlet of the air purifier 12 is connected to the input of the carbon dioxide adsorber 13, and the output of the carbon dioxide adsorber 13 is connected to the input of the expansion filter 14, forming a linear arrangement of components along the airflow direction. One end of the cold exchanger 21 of the pre-cooling system 2 is connected to the output of the expansion filter 14 via a pipeline, and the other end of the cold exchanger 21 is equipped with a stone-type cold accumulator with a built-in coil. An automatic valve box 22 is installed on the connecting pipeline between the cold exchanger 21 and the cold accumulator. The automatic valve box 22 is fixed in the middle of the pipeline by a flange to realize real-time control of the airflow direction and flow rate, ensuring that the pre-purified air enters the cold accumulator in an orderly manner to complete the cooling.

[0021] The distillation system 3 is located downstream of the precooling system 2. The outlet of the cold exchanger 21 is connected to the lower column inlet of the distillation unit 31 via a pipeline. The upper and lower columns are arranged vertically, with a condenser-evaporator 32 sandwiched between them. The two ends of the condenser-evaporator 32 are connected to the bottom of the upper column and the top of the lower column via sealed pipelines, respectively. One outlet of the lower column is connected to the input of the liquid air absorber 35 via a pipeline, while the other outlet is connected to the input of the liquid nitrogen subcooler 34. The output of the liquid nitrogen subcooler 34 extends to the top opening of the upper column via a throttling pipeline, and the output of the liquid air absorber 35 is connected to the input of the liquid oxygen absorber 36 via a pipeline. A liquid oxygen pump is installed beside the liquid oxygen absorber 36. The inlet and outlet of the liquid oxygen pump are connected to the bottom and top of the liquid oxygen absorber 36 via circulation pipelines, respectively. Meanwhile, one outlet of the upper column is connected to the input of the nitrogen evaporator 33 via a pipeline, forming a compact component layout around the upper and lower columns. The refrigerant tank 41 of the cold replenishment system 4 is fixedly installed beside the distillation system 3. The bottom outlet of the refrigerant tank 41 is connected to the inlet of the hydraulic pump 42 via a pipeline. The outlet of the hydraulic pump 42 extends to the cold exchanger 21 of the precooling system 2 via a pipeline and is connected to the pre-set refrigerant heating channel inside the cold exchanger 21. The outlet of this heating channel is connected to the input of the expander 43 via a pipeline. The output of the expander 43 is connected to the input of the cold regenerator 44 via a pipeline. The output of the cold regenerator 44 is connected to the middle air inlet of the upper column of the distillation system 3 via a replenishment cooling pipeline. The outlet pipeline of the air compressor 11 in the air purification system 1 is equipped with a pressure regulating component. This component is connected to the air inlet of the cold exchanger 21 of the precooling system 2 and the air inlet of the lower column of the distillation system 3 via branch pipelines to ensure that the compressor exhaust pressure is adapted to the air inlet pressure requirements of the subsequent systems and to achieve stable airflow pressure throughout the process.

[0022] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A tubular oxygen-nitrogen air separation device with isobaric separation, characterized in that, include: An air purification system (1) is provided with multiple purification devices to pre-purify the air, remove carbon dioxide and solid impurities from the air, and obtain pre-purified air. A precooling system (2) is provided with a cold exchanger (21) to cool the pre-purified air; A distillation system (3) includes a distillation apparatus (31) for isobaric separation of nitrogen and oxygen.

2. The tubular oxygen-nitrogen air separation device with isobaric separation according to claim 1, characterized in that, The isobaric separation tubular oxygen-nitrogen-air separation device further includes a cold replenishment system (4), which includes: A refrigerant tank (41) is located at one end of the distillation system (3) and has a cavity for containing liquid refrigerant. A hydraulic pump (42) is located between the refrigerant tank (41) and the precooling system (2) to pump liquid refrigerant into the precooling system (2) to heat it into a superheated refrigerant flow. An expander (43) is connected to the superheated refrigerant flow to expand and cool the superheated refrigerant flow; The cold regenerator (44) is connected to the expander (43) to cool the superheated refrigerant flow after expansion and cooling and to replenish the cooling of the distillation system (3).

3. The isobaric separation tubular oxygen-nitrogen air separator according to claim 1, characterized in that, The air purification system (1) includes: An air compressor (11) drives an airflow; An air purifier (12) is connected to the output end of the air compressor (11) to purify the airflow into a pre-purified airflow. A carbon dioxide adsorber (13) is provided at the output end of the air purifier (12) to remove carbon dioxide from the pre-purified airflow; An expansion filter (14) is provided at the output end of the carbon dioxide adsorber (13) to remove impurities from the pre-purified airflow after adsorption treatment by the carbon dioxide adsorber (13).

4. The tubular oxygen-nitrogen air separation device with isobaric separation according to claim 1, characterized in that, The precooling system (2) includes: A cold exchanger (21) is provided at one end of the cold exchanger (21) and the other end of the cold exchanger (21) is connected to the output end of the air purification system (1) to cool the pre-purified air. An automatic valve box (22) is located between the cold exchanger (21) and the cold storage unit to control the airflow direction and flow rate of the pre-purified air.

5. The tubular oxygen-nitrogen air separation device with isobaric separation according to claim 1, characterized in that, The distillation system (3) includes: A distillation apparatus (31) includes an upper column and a lower column and is connected to the precooling system (2). The lower column precools and separates the pre-purified air into an oxygen-rich liquid air stream and a first gaseous nitrogen stream. A condenser-evaporator (32) is disposed between the upper tower and the lower tower and is formed as a long tube. Nitrogen evaporator (33), which is connected to the upper column to condense the second gaseous nitrogen stream output from the upper column to obtain a second liquid nitrogen stream; Liquid nitrogen subcooler (34), the liquid nitrogen subcooler (34) is located at the output end of the lower column and the first gaseous nitrogen stream is cooled into a first liquid nitrogen stream and transported to the upper column; Liquid air absorber (35), the liquid air absorber (35) is located at the output end of the lower tower to remove carbon dioxide, dry ice and acetylene from the oxygen-rich liquid air stream; Liquid oxygen absorber (36) is located at the output end of liquid air absorber (35) and is internally circulated to remove acetylene under the drive of liquid oxygen pump.

6. The tubular oxygen-nitrogen air separation device with isobaric separation according to claim 1, characterized in that, In the air purification system (1), the exhaust pressure of the air compressor (11) is adapted to the isobaric separation requirements of the precooling system (2) and the distillation system (3) to ensure that the air flow maintains a stable pressure in each system.

7. The isobaric separation tubular oxygen-nitrogen air separator according to claim 5, characterized in that, The lower column of the distillation system (3) is thermally coupled to the upper column through a condenser-evaporator (32). The oxygen-rich liquid air from the lower column is depressurized by a throttling valve and then enters the middle of the upper column. The first liquid nitrogen is depressurized by a throttling valve and then enters the top of the upper column.

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