An oxygen recovery air separation device

Abstract

This invention discloses an oxygen recovery air separation unit, characterized by comprising: a washing, dust removal, cooling, and dehumidification system; a recovered flue gas pressurization system; a recovered flue gas purification and drying system; an air compression system; an air precooling and purification system; and a low-temperature distillation system. The washing, dust removal, cooling, and dehumidification system washes, removes dust, cools, and dehumidifies the oxygen-enriched flue gas, then introduces it into the recovered flue gas purification and drying system to adsorb residual moisture, obtaining dry and clean flue gas. The air compression system compresses, precools, and purifies the raw air, then introduces it into the low-temperature distillation system for low-temperature distillation to obtain oxygen. In this invention, the air separation unit adopts an integrated modular system structure, which can effectively remove metal oxide dust from the recovered flue gas, while simultaneously achieving cooling and dehumidification, reducing the activity of oxygen molecules. This not only enables high-efficiency purification, recovery, and reuse of oxygen from oxygen-enriched flue gas, but also significantly reduces equipment investment and operating energy consumption.

Description

Technical Field

[0001] This invention relates to the field of oxygen recovery technology, and more particularly to an oxygen recovery air separation device. Background Technology

[0002] Lithium-ion batteries are batteries composed of lithium alloy metal oxides as positive electrode materials, graphite as negative electrode materials, and non-aqueous electrolytes. They are characterized by being environmentally friendly, high-performance, and having a long operating time, and have become one of the key areas of development in the battery industry. In the production process of lithium battery positive electrode materials, a large amount of pure oxygen is required, which also generates a large amount of high-temperature, high-humidity, near-normal-pressure oxygen-enriched flue gas. In order to recover and utilize the oxygen in the oxygen-enriched flue gas, it is necessary to treat the oxygen-enriched flue gas.

[0003] Chinese Patent Publication No. CN113587550A discloses a "Recovery Device for Oxygen from Air Separation," comprising an air filter, an air compressor, an air cooler, a molecular sieve, a circulating booster compressor, an expander, a main heat exchanger, a distillation column, an oxygen pipeline network, and an oxygen storage tank. The air filter's input end is connected to an air source, and its output end is connected to the air compressor. The air compressor's output end is connected to the air cooler, and the other end of the air cooler is connected to the molecular sieve. Gas purified by the molecular sieve is input to the circulating booster compressor, whose output end is connected to the booster end of the expander. The expander's expansion end is connected to the distillation column, which is used to deliver oxygen and liquid oxygen to the oxygen pipeline network and the oxygen storage tank, respectively.

[0004] The existing method for recovering oxygen from oxygen-enriched flue gas usually involves adding an oxygen purification and recovery device to purify and reuse the oxygen-enriched flue gas. Although this approach can improve the utilization rate of oxygen, it will greatly increase the investment in equipment, and the oxygen recovery efficiency in oxygen-enriched flue gas is low. Summary of the Invention

[0005] The purpose of this invention is to provide an oxygen recovery air separation device that can not only efficiently purify, recover, and reuse oxygen in oxygen-enriched flue gas, but also greatly reduce equipment investment.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an oxygen recovery air separation device, characterized in that it includes: a washing, dust removal, cooling and dehumidification system, a flue gas pressurization system, a flue gas purification and drying system, an air compression system, an air precooling and purification system, and a low-temperature distillation system;

[0007] The washing, dust removal, cooling, and dehumidification system is used to wash, dust-reducing, cool, and dehumidify oxygen-rich flue gas, then pressurize it through the flue gas pressurization system, and introduce it into the flue gas purification and drying system to adsorb residual moisture, thereby obtaining dry and clean flue gas.

[0008] The air compression system is used to compress the raw material air. After the raw material air is pre-cooled and purified by the air pre-cooling and purification system, it is introduced into the low-temperature distillation system for low-temperature distillation to obtain oxygen.

[0009] As a further description of the above technical solution:

[0010] The washing, dust removal, cooling, and dehumidification system includes a flue gas scrubbing tower and a second cooling water pump, and the flue gas recovery and pressurization system includes a flue gas blower.

[0011] As a further description of the above technical solution:

[0012] The flue gas scrubbing tower is equipped with a flue gas inlet pipe, a flue gas outlet pipe, and a cooling water pipe. It is connected to a flue gas blower through the flue gas outlet pipe and to a second cooling water pump through the cooling water pipe.

[0013] As a further description of the above technical solution:

[0014] The recovered flue gas purification and drying system includes a third purifier, a fourth purifier, and an electric heater. The third and fourth purifiers are connected to the electric heater via a regeneration gas pipeline.

[0015] As a further description of the above technical solution:

[0016] The air compression system includes an air compressor and a booster compressor, and the air precooling and purification system includes an air cooling tower, a first cooling water pump, a chiller unit, a chilled water pump, a water cooling tower, a first purifier, and a second purifier.

[0017] As a further description of the above technical solution:

[0018] The air compressor is connected to the air cooling tower via a pipeline, and the air cooling tower is connected to the chiller unit and the first cooling water pump via a pipeline. The chiller unit is connected to the water cooling tower via a pipeline, and the air cooling tower is connected to the first purifier and the second purifier via a pipeline.

[0019] As a further description of the above technical solution:

[0020] The cryogenic distillation system includes a booster expander, a liquid oxygen pump, a main heat exchanger, a lower column, a main condenser-evaporator, an upper column, and a subcooler.

[0021] As a further description of the above technical solution:

[0022] The booster expander's booster end is connected to one of its rear ends via a pipeline. The booster expander's booster end is also connected to a booster end aftercooler via a pipeline. The booster end aftercooler is connected to the main heat exchanger via a pipeline. The main heat exchanger is connected to the booster expander via a pipeline. The booster expander is connected to the lower tower via a pipeline, and another pipeline connects it to the main heat exchanger. The main heat exchanger is connected to the lower tower via a throttling valve. The lower tower is connected to a subcooler via a pipeline. The subcooler is connected to the upper tower via a pipeline. A main condenser-evaporator is located between the lower and upper towers. The main condenser-evaporator is connected to a liquid oxygen pump via a pipeline. The liquid oxygen pump is connected to the main heat exchanger via a pipeline.

[0023] A method of using an oxygen recovery air separation unit includes the following steps:

[0024] S01: After the raw material air is pressurized to a certain pressure by the air compressor, it enters the air cooling tower and comes into direct contact with the cooling water from the circulating water system and the chilled water that has been further cooled by the water cooling tower and chiller unit to achieve staged cooling. The cooled processing air enters the first purifier to adsorb and remove residual moisture, carbon dioxide and hydrocarbons to obtain dry and clean air.

[0025] S02: A portion of the dry and clean air directly enters the main heat exchanger and is cooled to near saturation temperature before entering the lower tower. The remaining air is compressed by the booster compressor and divided into two streams. One stream is directly sent to the main heat exchanger to provide vaporization heat for liquid oxygen. After being cooled into liquid air, it enters the lower tower after being throttled. The other stream passes through the booster expander and the booster end aftercooler in sequence before entering the main heat exchanger. After being cooled to a certain temperature, it is drawn out to the booster expander, expanded, and then enters the lower tower.

[0026] S03: Atmospheric pressure oxygen-enriched flue gas enters the flue gas scrubbing tower and comes into direct contact with cooling water from the second cooling water pump. The oxygen-enriched flue gas is scrubbed, dust removed, cooled and dehumidified. After being scrubbed, cooled and dehumidified, the flue gas is pressurized by the flue gas blower and enters the third purifier to adsorb and remove residual moisture. The dry and clean flue gas directly enters the main heat exchanger to be cooled to a certain temperature and then sent to the upper tower.

[0027] S04: High-purity liquid nitrogen is obtained from the top of the lower column. Part of it is used as reflux liquid for the lower column distillation. The remaining liquid nitrogen is throttled into the upper column after passing through the cooler to provide reflux liquid for the upper column distillation. The oxygen-enriched liquid at the bottom of the lower column is throttled into the upper column after passing through the cooler to participate in the distillation. High-purity liquid oxygen is obtained from the main condenser-evaporator. An appropriate amount is extracted and pressurized to the required pressure by the liquid oxygen pump and sent to the main heat exchanger to exchange heat with high-pressure air, vaporizing into pressurized oxygen product, which is sent to the oxygen product pipeline network. Part of the liquid oxygen is subcooled by the cooler and sent downstream as a liquid product.

[0028] The oxygen recovery air separation device provided by the present invention, as described above, has the following beneficial effects:

[0029] This air separation unit adopts an integrated modular system structure, which can effectively remove metal oxide dust from the flue gas, while achieving the effects of cooling and dehumidification, reducing the activity of oxygen molecules, and ensuring the safe operation of downstream equipment. It can not only achieve high-efficiency purification, recovery and reuse of oxygen in oxygen-enriched flue gas, but also greatly reduce equipment investment and operating energy consumption, and improve utilization rate. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0031] Figure 1 This is a schematic diagram of an oxygen recovery air separation device provided in an embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Flue gas scrubbing tower; 2. Second cooling water pump; 3. Flue gas blower; 4. Third purifier; 5. Fourth purifier; 6. Electric heater; 7. Air compressor; 8. Air cooling tower; 9. Water cooling tower; 10. Chiller unit; 11. Chilled water pump; 12. First cooling water pump; 13. First purifier; 14. Second purifier; 15. Booster compressor; 16. Booster expander; 17. Main heat exchanger; 18. Upper tower; 19. Liquid oxygen pump; 20. Lower tower; 21. Subcooler; 22. Main condenser-evaporator; 23. Booster end aftercooler. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0035] like Figure 1 As shown, an oxygen recovery air separation unit includes: a washing, dust removal, cooling and dehumidification system, a flue gas pressurization system, a flue gas purification and drying system, an air compression system, an air precooling and purification system, and a low-temperature distillation system;

[0036] The washing, dust removal, cooling and dehumidification system is used to wash, dust remove, cool and dehumidify oxygen-rich flue gas, then pressurize it through the flue gas recovery and pressurization system, and introduce it into the flue gas recovery and purification drying system to adsorb residual moisture, thereby obtaining dry and clean flue gas.

[0037] The washing, dust removal, cooling, and dehumidification system can effectively remove metal oxide dust from the recovered flue gas, while simultaneously cooling and dehumidifying it, reducing the activity of oxygen molecules, and ensuring the safe operation of downstream equipment.

[0038] The air compression system is used to compress the raw material air. After the raw material air is pre-cooled and purified by the air pre-cooling and purification system, it is introduced into the low-temperature distillation system for low-temperature distillation to obtain oxygen.

[0039] The air precooling and purification system adopts structured packed tower technology, which is safe and reliable with a high oxygen extraction rate. It can not only achieve high-efficiency purification, recovery and reuse of oxygen in oxygen-enriched flue gas, but also greatly reduce equipment investment. At the same time, it has a variety of product structures and can produce oxygen, liquid oxygen, nitrogen and other gases to meet different customer needs. The raw materials are air and oxygen-enriched flue gas, and it has a wide range of applicable qualities for oxygen-enriched flue gas.

[0040] The washing, dust removal, cooling and dehumidification system includes a flue gas scrubbing tower 1 and a second cooling water pump 2. The flue gas recovery and pressurization system includes a flue gas blower 3. The flue gas scrubbing tower 1 is equipped with a flue gas inlet pipe, a flue gas outlet pipe and a cooling water pipe. It is connected to the flue gas blower 3 through the flue gas outlet pipe and to the second cooling water pump 2 through the cooling water pipe.

[0041] The flue gas purification and drying system includes a third purifier 4, a fourth purifier 5, and an electric heater 6. The third purifier 4 and the fourth purifier 5 are connected to the electric heater 6 through a regeneration gas pipeline.

[0042] The air compression system includes an air compressor 7 and a booster compressor 15. The air precooling and purification system includes an air cooling tower 8, a first cooling water pump 12, a chiller unit 10, a chilled water pump 11, a water cooling tower 9, a first purifier 13, and a second purifier 14. The air compressor 7 is connected to the air cooling tower 8 through a pipeline. The air cooling tower 8 is connected to the chiller unit 10 and the first cooling water pump 12 through a pipeline. The chiller unit 10 is connected to the water cooling tower 9 through a pipeline. The air cooling tower 8 is connected to the first purifier 13 and the second purifier 14 through a pipeline.

[0043] The cryogenic distillation system includes a booster expander 16, a liquid oxygen pump 19, a main heat exchanger 17, a lower column 20, a main condenser-evaporator 22, an upper column 18, and a subcooler 21. The booster expander 16 is connected to the downstream end of the booster 15 via a pipeline. The booster expander 16 is also connected to the booster aftercooler 23 via a pipeline. The booster aftercooler 23 is connected to the main heat exchanger 17 via a pipeline. The main heat exchanger 17 is connected to the booster expander 16 via a pipeline. The booster expander 16 is connected to the lower tower 20 via a pipeline, and another pipeline is connected to the main heat exchanger 17. The main heat exchanger 17 is connected to the lower tower 20 via a throttle valve. The lower tower 20 is connected to the subcooler 21 via a pipeline. The subcooler 21 is connected to the upper tower 18 via a pipeline. A main condenser-evaporator 22 is provided between the lower tower 20 and the upper tower 18. The main condenser-evaporator 22 is connected to the liquid oxygen pump 19 via a pipeline. The liquid oxygen pump 19 is connected to the main heat exchanger 17 via a pipeline.

[0044] A method of using an oxygen recovery air separation unit includes the following steps:

[0045] S01: After the raw material air is pressurized to a certain pressure by the air compressor 7, it enters the air cooling tower 8 and comes into direct contact with the cooling water from the circulating water system and the chilled water further cooled by the water cooling tower 9 and the chiller unit 10 to achieve staged cooling. The cooled processing air enters the first purifier 13 to adsorb and remove residual moisture, carbon dioxide and hydrocarbons to obtain dry and clean air.

[0046] S02: A portion of the dry, clean air directly enters the main heat exchanger 17 and is cooled to near saturation temperature before entering the lower tower 20. The remaining air is compressed by the booster compressor 15 and divided into two streams. One stream is directly sent to the main heat exchanger 17 to provide vaporization heat for liquid oxygen. After being cooled into liquid air, it enters the lower tower 20 after throttling. The other stream passes through the booster expander 16 and the booster end aftercooler 23 before entering the main heat exchanger 17. After being cooled to a certain temperature, it is extracted to the booster expander 16, expanded, and then enters the lower tower 20. The air enters the bottom of the lower tower 20 and, as rising steam, passes through each packing from bottom to top, contacting the liquid on the packing and exchanging heat and mass. High-purity nitrogen is obtained at the top. This nitrogen is condensed into liquid nitrogen in the main condenser evaporator 22 and, as reflux liquid, flows down the packing and exchanges heat and mass with the rising steam. Oxygen-rich liquid air is obtained at the bottom of the lower tower 20.

[0047] S03: Atmospheric pressure oxygen-enriched flue gas enters flue gas scrubbing tower 1 and comes into direct contact with cooling water from the second cooling water pump 2 to scrub, remove dust, cool and dehumidify the oxygen-enriched flue gas. After scrubbing, cooling and dehumidifying, the flue gas is pressurized by flue gas blower 3 and enters the third purifier 4 to adsorb and remove residual moisture. The dry and clean flue gas directly enters the main heat exchanger 17 to be cooled to a certain temperature and then sent to the upper tower 18.

[0048] S04: High-purity liquid nitrogen is obtained at the top of the lower column 20. Part of it is used as reflux liquid for the rectification of the lower column 20. The remaining liquid nitrogen is throttled into the upper column 18 after passing through the cooler 21 to provide reflux liquid for the rectification of the upper column 18. The oxygen-rich liquid at the bottom of the lower column 20 is throttled into the upper column 18 after passing through the cooler 21 to participate in the rectification. High-purity liquid oxygen is obtained in the main condenser evaporator 22. An appropriate amount is extracted and pressurized to the required pressure by the liquid oxygen pump 19 and sent to the main heat exchanger 17 to exchange heat with high-pressure air, and vaporized into pressurized oxygen product, which is sent to the oxygen product pipeline network. Part of the liquid oxygen is subcooled by the cooler 21 and sent downstream as a liquid product.

[0049] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method of using an oxygen recovery air separation device, characterized in that, The oxygen recovery air separation unit includes: a washing, dust removal, cooling and dehumidification system, a flue gas pressurization system, a flue gas purification and drying system, an air compression system, an air precooling and purification system, and a low-temperature distillation system; The washing, dust removal, cooling, and dehumidification system is used to wash, dust-reducing, cool, and dehumidify oxygen-rich flue gas, then pressurize it through the flue gas pressurization system, and introduce it into the flue gas purification and drying system to adsorb residual moisture, thereby obtaining dry and clean flue gas. The air compression system is used to compress the raw material air. After the raw material air is pre-cooled and purified by the air pre-cooling and purification system, it is introduced into the cryogenic distillation system for cryogenic distillation to obtain oxygen. The usage method includes the following steps: S01: After the raw material air is pressurized to a certain pressure by the air compressor, it enters the air cooling tower and comes into direct contact with the cooling water from the circulating water system and the chilled water that has been further cooled by the water cooling tower and chiller unit to achieve staged cooling. The cooled processing air enters the first purifier to adsorb and remove residual moisture, carbon dioxide and hydrocarbons to obtain dry and clean air. S02: A portion of the dry and clean air directly enters the main heat exchanger and is cooled to near saturation temperature before entering the lower tower. The remaining air is compressed by the booster compressor and divided into two streams. One stream is directly sent to the main heat exchanger to provide vaporization heat for liquid oxygen. After being cooled into liquid air, it enters the lower tower after being throttled. The other stream passes through the booster expander and the booster end aftercooler in sequence before entering the main heat exchanger. After being cooled to a certain temperature, it is drawn out to the booster expander, expanded, and then enters the lower tower. S03: Atmospheric pressure oxygen-enriched flue gas enters the flue gas scrubbing tower and comes into direct contact with cooling water from the second cooling water pump. The oxygen-enriched flue gas is scrubbed, dust removed, cooled and dehumidified. After being scrubbed, cooled and dehumidified, the flue gas is pressurized by the flue gas blower and enters the third purifier to adsorb and remove residual moisture. The dry and clean flue gas directly enters the main heat exchanger to be cooled to a certain temperature and then sent to the upper tower. S04: High-purity liquid nitrogen is obtained from the top of the lower column. Part of it is used as reflux liquid for the lower column distillation. The remaining liquid nitrogen is throttled into the upper column after passing through the cooler to provide reflux liquid for the upper column distillation. The oxygen-enriched liquid at the bottom of the lower column is throttled into the upper column after passing through the cooler to participate in the distillation. High-purity liquid oxygen is obtained from the main condenser-evaporator. An appropriate amount is extracted and pressurized to the required pressure by the liquid oxygen pump and sent to the main heat exchanger to exchange heat with high-pressure air, vaporizing into pressurized oxygen product, which is sent to the oxygen product pipeline network. Part of the liquid oxygen is subcooled by the cooler and sent downstream as a liquid product.

2. The method of using an oxygen recovery air separation device according to claim 1, characterized in that: The washing, dust removal, cooling and dehumidification system includes a flue gas scrubbing tower and a second cooling water pump, and the flue gas recovery and pressurization system includes a flue gas blower (3).

3. The method of using an oxygen recovery air separation device according to claim 2, characterized in that: The flue gas scrubbing tower (1) is equipped with a flue gas inlet pipe, a flue gas outlet pipe and a cooling water pipe. It is connected to a flue gas blower through the flue gas outlet pipe and to a second cooling water pump through the cooling water pipe.

4. The method of using an oxygen recovery air separation device according to claim 1, characterized in that: The recovered flue gas purification and drying system includes a third purifier, a fourth purifier, and an electric heater. The third and fourth purifiers are connected to the electric heater via a regeneration gas pipeline.

5. The method of using an oxygen recovery air separation device according to claim 1, characterized in that: The air compression system includes an air compressor and a booster compressor, and the air precooling and purification system includes an air cooling tower, a first cooling water pump, a chiller unit, a chilled water pump, a water cooling tower, a first purifier, and a second purifier.

6. The method of using an oxygen recovery air separation device according to claim 5, characterized in that: The air compressor is connected to the air cooling tower via a pipeline, and the air cooling tower is connected to the chiller unit and the first cooling water pump via a pipeline. The chiller unit is connected to the water cooling tower via a pipeline, and the air cooling tower is connected to the first purifier and the second purifier via a pipeline.

7. The method of using an oxygen recovery air separation device according to claim 1, characterized in that: The cryogenic distillation system includes a booster expander, a liquid oxygen pump, a main heat exchanger, a lower column, a main condenser-evaporator, an upper column, and a subcooler.

8. The method of using an oxygen recovery air separation device according to claim 7, characterized in that: The booster expander's booster end is connected to one of its rear ends via a pipeline. The booster expander's booster end is also connected to a booster end aftercooler via a pipeline. The booster end aftercooler is connected to the main heat exchanger via a pipeline. The main heat exchanger is connected to the booster expander via a pipeline. The booster expander is connected to the lower tower via a pipeline, and another pipeline connects it to the main heat exchanger. The main heat exchanger is connected to the lower tower via a throttling valve. The lower tower is connected to a subcooler via a pipeline. The subcooler is connected to the upper tower via a pipeline. A main condenser-evaporator is located between the lower and upper towers. The main condenser-evaporator is connected to a liquid oxygen pump via a pipeline. The liquid oxygen pump is connected to the main heat exchanger via a pipeline.

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