A process for the complete liquefaction of conventional air separation products based on liquid air energy storage

Abstract

This invention provides a fully liquefied process for conventional air separation products based on liquid air energy storage, relating to the field of air separation energy storage technology. During off-peak electricity periods, the liquefied air energy storage device uses low-cost electricity to liquefy and store air. The liquid air is then pumped and vaporized, and its cooling capacity is used for the liquefaction of air separation oxygen and nitrogen products. The vaporized liquid air and the air separation oxygen and nitrogen products undergo heat exchange and reheating before being supplied as feed air to the air separation unit. This invention requires no technical modifications to the air liquefaction energy storage device or the air separation unit, ensuring that the air separation operating parameters are unaffected by the energy storage and liquefaction systems. It enables the liquefaction of conventional air separation products using low-cost off-peak electricity, reducing the liquefaction cost of air separation unit products while achieving large-scale and distributed energy storage.

Description

Technical Field

[0001] This invention relates to the field of air separation energy storage technology, and in particular to a process for the complete liquidification of conventional air separation products based on liquid air energy storage. Background Technology

[0002] With the development of science and technology, society's demand for cryogenic liquid products is increasing, such as liquid nitrogen, liquid argon, and liquid oxygen. Currently, large-scale air separation units that produce oxygen, nitrogen, and argon primarily produce gaseous products. While large-scale liquefaction of air separation products is not technically difficult, it involves three issues: 1) Adaptive technological modifications to the air separation unit and air liquefaction energy storage system, especially the air separation unit, would require the redevelopment of air separation process technology, necessitating significant financial and time investment; 2) It is essential to ensure that the air separation operating parameters remain stable and unaffected by the energy storage and liquefaction systems; 3) If conventional gas liquefaction technology is used without adapting the air separation system, the high electricity costs associated with liquefaction will be a concern. Summary of the Invention

[0003] To address the aforementioned technical problems in existing technologies, this invention provides a fully liquefied process for conventional air separation products based on liquid air energy storage. The technical solution is as follows:

[0004] A process for the complete liquefaction of conventional air separation products based on liquid air energy storage, the process comprising:

[0005] S1. During off-peak electricity periods, the air liquefaction unit operates at full load. Ambient air is compressed and pressurized by the air compressor and then enters the air purifier to purify and remove moisture, carbon dioxide and nitrogen-hydrogen compounds. After the cold energy is recovered by the cold storage heat exchanger, it enters the air liquefaction unit for liquefaction. The liquefied air is stored in the liquid air storage tank and stops operating during non-off-peak electricity periods.

[0006] S2. During off-peak and non-off-peak electricity periods, the liquid air in the liquid air storage tank is pumped into the oxygen-nitrogen liquefaction unit by the liquid air pump. After exchanging heat with oxygen and nitrogen in the oxygen-nitrogen liquefaction unit, the liquid air enters the gas heat exchanger for further heat exchange, and then enters the cold storage heat exchanger to recover the excess cold energy of the air, and then enters the air separation unit as the raw material gas for air separation.

[0007] S3. The air entering the air separation unit is separated in the air separation unit to produce product oxygen and product nitrogen;

[0008] S4. In step S3, the product oxygen is compressed and pressurized by the oxygen compressor, then enters the gas heat exchanger through the oxygen cooler to exchange heat with oxygen and nitrogen from the oxygen-liquid separator and nitrogen-liquid separator, and then enters the oxygen-nitrogen liquefaction unit to exchange heat with liquid air and liquefy it before entering the oxygen expander and then the oxygen-liquid separator.

[0009] S5. In step S3, the product nitrogen gas is compressed and pressurized by the nitrogen compressor, then enters the gas heat exchanger through the nitrogen cooler to exchange heat with oxygen and nitrogen from the oxygen-liquid separator and the nitrogen-liquid separator. After entering the oxygen-nitrogen liquefaction unit, it exchanges heat with liquid air and liquefies before entering the nitrogen expander, and then enters the nitrogen-liquid separator.

[0010] In step S1, the amount of liquefied air produced and stored in the liquid air storage tank during off-peak electricity periods by the air liquefaction device meets the daily raw material air supply needs of the air separation unit.

[0011] Steps S2-S5 are performed during both off-peak and non-off-peak electricity periods.

[0012] In another process embodiment of the present invention, in step S2, the liquid air in the liquid air storage tank is divided into two parts, A and B, after being transported by the liquid air pump. Part A directly enters the lower tower of the air separation unit, while part B is depressurized by the liquid air expander and then enters the nitrogen liquefaction unit and nitrogen heat exchanger for further heat exchange. After that, it enters the gas heat exchanger to recover the excess cold energy of the air, and then enters the air separation unit as the raw material gas for air separation.

[0013] Of these, part B accounts for 17%-20% of the total liquid air volume.

[0014] In this process, the product oxygen produced by the air separation unit is drawn out in liquid form from the low-pressure side of the air separation unit's condenser-evaporator and stored in a liquid oxygen storage tank as liquid oxygen product.

[0015] The nitrogen produced by the air separation unit is compressed and pressurized by the nitrogen compressor, then enters the gas heat exchanger through the nitrogen cooler. After exchanging heat with the nitrogen from the top of the nitrogen-liquid separator, the product nitrogen enters the nitrogen liquefaction unit and exchanges heat with liquid air to liquefy it before entering the nitrogen expander. After expanding and depressurizing, it enters the nitrogen-liquid separator.

[0016] In this invention, the oxygen at the top of the oxygen-liquid separator is reheated by a gas heat exchanger and then returned to the inlet of the oxygen compressor, while the liquid oxygen at the bottom of the oxygen-liquid separator enters the liquid oxygen storage tank for storage as a liquid oxygen product.

[0017] The nitrogen gas at the top of the nitrogen-liquid separator is reheated by a gas heat exchanger and then returns to the inlet of the nitrogen compressor. The liquid nitrogen at the bottom of the nitrogen-liquid separator enters the liquid nitrogen storage tank for storage as a liquid nitrogen product.

[0018] The air liquefaction device and air separation device are conventional air liquefaction devices and conventional air separation devices.

[0019] Both oxygen compressors and nitrogen compressors can be multi-stage compressors with intercooling.

[0020] The beneficial effects of the technical solutions provided by the embodiments of the present invention include at least the following:

[0021] The above-described scheme, based on a conventional air separation product liquefaction process using liquid-air energy storage, utilizes low-cost electricity to liquefy and store air during off-peak electricity periods. During both off-peak and non-off-peak periods, the liquid air is pumped and vaporized, and its cooling capacity is used for the liquefaction of oxygen and nitrogen products in the air separation process. After heat exchange, the vaporized liquid air and the oxygen and nitrogen products enter a regenerative heat exchanger to recover excess cooling capacity from the air, which is then used as feedstock air to supply the air separation unit. This invention requires no technical modifications to the air liquefaction energy storage device or the air separation unit, enabling the liquefaction of conventional air separation products using low-cost off-peak electricity. This reduces the liquefaction cost of air separation unit products while achieving large-scale and distributed energy storage. This process can provide technical support for the reuse of idle air separation units after the replacement of new equipment in the metallurgical and chemical industries. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flow chart of a conventional air separation product fully liquefied based on liquid air energy storage, provided by an embodiment of the present invention.

[0024] Figure 2 This is another form of process flow diagram for the full liquefaction of conventional air separation products based on liquid air energy storage, provided in Embodiment 2 of the present invention.

[0025] Wherein: 1-Air liquefaction unit; 2-Liquid air storage tank; 3-Liquid air pump; 4-Oxygen-nitrogen liquefaction unit; 5-Air separation unit; 6-Oxygen compressor; 7-Nitrogen compressor; 8-Oxygen cooler; 9-Nitrogen cooler; 10-Gas heat exchanger; 11-Oxygen expander; 12-Nitrogen expander; 13-Oxygen-liquid separator; 14-Nitrogen-liquid separator; 15-Liquid oxygen storage tank; 16-Liquid nitrogen storage tank; 17-Nitrogen liquefaction unit; 18-Liquid air expander; 19-Cryogenic heat exchanger; 20-Air compressor; 21-Air purifier. Detailed Implementation

[0026] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0027] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0028] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0029] This invention provides a process for the complete liquefaction of conventional air separation products based on liquid-air energy storage. For example... Figure 1 The diagram shown illustrates a process flow chart for the complete liquefaction of conventional air separation products based on liquid air energy storage. This process may include the following steps:

[0030] S1. During off-peak electricity periods, the air liquefaction device 1 operates at full load. After the ambient air is compressed and pressurized by the air compressor 20, it enters the air purifier 21 to purify and remove moisture, carbon dioxide and nitrogen-hydrogen compounds. After the cold energy is recovered by the cold storage heat exchanger 19, it enters the air liquefaction device 1 for liquefaction. The liquefied air is stored in the liquid air storage tank 2. During non-off-peak electricity periods, the operation stops.

[0031] S2. During off-peak and non-off-peak electricity periods, the liquid air in the liquid air storage tank 2 is pumped into the oxygen-nitrogen liquefaction unit 4 by the liquid air pump 3. After exchanging heat with oxygen and nitrogen in the oxygen-nitrogen liquefaction unit 4, the liquid air enters the gas heat exchanger 10 for further heat exchange, and then enters the cold storage heat exchanger 19 to recover the excess cold energy of the air, and then enters the air separation unit 5 as the raw material gas for air separation.

[0032] S3. The air entering the air separation unit 5 is separated in the air separation unit 5 to produce product oxygen and product nitrogen.

[0033] S4. In step S3, the product oxygen is compressed and pressurized by the oxygen compressor 6, then enters the gas heat exchanger 10 through the oxygen cooler 8 to exchange heat with the oxygen and nitrogen from the oxygen-liquid separator 13 and the nitrogen-liquid separator 14, and then enters the oxygen-nitrogen liquefaction unit 4 to exchange heat with the liquid air and liquefy it before entering the oxygen expander 11, and then entering the oxygen-liquid separator 13.

[0034] S5. In step S3, the product nitrogen gas is compressed and pressurized by the nitrogen compressor 7, then enters the gas heat exchanger 10 through the nitrogen cooler 9 to exchange heat with the oxygen and nitrogen from the oxygen-liquid separator 13 and the nitrogen-liquid separator 14. After entering the oxygen-nitrogen liquefaction unit 4, it exchanges heat with the liquid air and is liquefied before entering the nitrogen expander 12, and then enters the nitrogen-liquid separator 14.

[0035] In step S1, the amount of liquefied air produced and stored in the air liquefaction tank 2 during off-peak electricity periods meets the daily raw material air supply needs of the air separation unit.

[0036] The oxygen at the top of the oxygen-liquid separator 13 is reheated by the gas heat exchanger 10 and then returned to the inlet of the oxygen compressor 6. The liquid oxygen at the bottom of the oxygen-liquid separator 13 enters the liquid oxygen storage tank 15 and is stored as a liquid oxygen product.

[0037] The nitrogen gas at the top of the nitrogen gas-liquid separator 14 is reheated by the gas heat exchanger 10 and then returns to the inlet of the nitrogen compressor 7. The liquid nitrogen at the bottom of the nitrogen gas-liquid separator 14 enters the liquid nitrogen storage tank 16 for storage as a liquid nitrogen product.

[0038] The following description, in conjunction with specific embodiments, illustrates this point.

[0039] Example 1

[0040] like Figure 1 As shown, the conventional air liquefaction unit 1, liquid air storage tank 2, liquid air pump 3, oxygen-nitrogen liquefaction unit 4, conventional air separation unit 5, oxygen compressor 6, nitrogen compressor 7, oxygen cooler 8, nitrogen cooler 9, gas heat exchanger 10, oxygen expander 11, nitrogen expander 12, oxygen-liquid separator 13, nitrogen-liquid separator 14, liquid oxygen storage tank 15, liquid nitrogen storage tank 16, cold storage heat exchanger 19, air compressor 20, and air purifier 21 are arranged according to the process flow diagram.

[0041] Air compressor 20 is connected to air purifier 21. Air purifier 21 is connected to air inlet I of cold storage heat exchanger 19. Air outlet I of cold storage heat exchanger 19 is connected to conventional air liquefaction device 1. The outlet of conventional air liquefaction device 1 is connected to liquid air storage tank 2. The outlet of liquid air storage tank 2 is connected to air inlet of oxygen-nitrogen liquefaction device 4 via liquid air pump 3. Air outlet of oxygen-nitrogen liquefaction device 4 is connected to air inlet of gas heat exchanger 10. Air outlet of gas heat exchanger 10 is connected to air inlet II of cold storage heat exchanger 19. Air outlet II of cold storage heat exchanger 19 is connected to air separation device 5.

[0042] The oxygen outlet of the air separation unit 5 is connected to the oxygen compressor 6. The outlet of the oxygen compressor 6 is connected to the oxygen inlet of the oxygen cooler 8. The oxygen outlet of the oxygen cooler 8 is connected to the oxygen inlet I of the gas heat exchanger 10. The oxygen outlet I of the gas heat exchanger 10 is connected to the oxygen inlet of the oxygen-nitrogen liquefaction unit 4. The oxygen outlet of the oxygen-nitrogen liquefaction unit 4 is connected to the oxygen expander 11. The oxygen expander 11 is connected to the oxygen inlet of the oxygen-liquid separator 13. The gas outlet at the top of the oxygen-liquid separator 13 is connected to the oxygen inlet II of the gas heat exchanger 10. The oxygen outlet II of the gas heat exchanger 10 is connected to the inlet of the oxygen compressor 6. The liquid outlet at the bottom of the oxygen-liquid separator 13 is connected to the liquid oxygen storage tank 15.

[0043] The nitrogen outlet of the air separation unit 5 is connected to the nitrogen compressor 7. The outlet of the nitrogen compressor 7 is connected to the nitrogen inlet of the nitrogen cooler 9. The nitrogen outlet of the nitrogen cooler 9 is connected to the nitrogen inlet I of the gas heat exchanger 10. The nitrogen outlet I of the gas heat exchanger 10 is connected to the nitrogen inlet of the oxygen-nitrogen liquefaction unit 4. The nitrogen outlet of the oxygen-nitrogen liquefaction unit 4 is connected to the nitrogen expander 12. The nitrogen expander 12 is connected to the nitrogen inlet of the nitrogen gas-liquid separator 14. The gas outlet at the top of the nitrogen gas-liquid separator 14 is connected to the nitrogen inlet II of the gas heat exchanger 10. The nitrogen outlet II of the gas heat exchanger 10 is connected to the inlet of the nitrogen compressor 7. The liquid outlet at the bottom of the nitrogen gas-liquid separator 14 is connected to the liquid nitrogen storage tank 16.

[0044] The specific work process is as follows:

[0045] S1. During off-peak electricity periods, the conventional air liquefaction system operates at full load. Ambient air is compressed and pressurized by air compressor 20, purified by air purifier 21 to remove moisture, carbon dioxide and nitrogen-hydrogen compounds, and then enters air liquefaction device 1 for liquefaction after recovering cold energy by cold storage heat exchanger 19. The liquefied air is stored in liquid air storage tank 2. The amount of air liquefied meets the raw material air needs of the air separation system throughout the day. The system stops operating during non-off-peak electricity periods.

[0046] S2. During off-peak and non-off-peak electricity periods, the liquid air pump 3 delivers liquid air from the liquid air storage tank 2 into the oxygen-nitrogen liquefaction unit 4, where it exchanges heat with oxygen and nitrogen before entering the gas heat exchanger 10 for further heat exchange. After that, it enters the cold storage heat exchanger 19 to recover the excess cold energy of the air, and then enters the air separation unit 5 (including internal compression and external compression air separation units) as the raw material gas for air separation.

[0047] S3. During off-peak and non-off-peak electricity periods, the oxygen produced by the air separation unit 5 is compressed and pressurized by the oxygen compressor 6, then enters the gas heat exchanger 10 through the oxygen cooler 8. After exchanging heat with the oxygen and nitrogen from the oxygen-liquid separator 13 and the nitrogen-liquid separator 14, it enters the oxygen-nitrogen liquefaction unit 4 and exchanges heat with liquid air for liquefaction. After entering the oxygen expander 11, it enters the oxygen-liquid separator 13. The oxygen in the upper part of the oxygen-liquid separator is reheated by the gas heat exchanger 10 and returns to the inlet of the oxygen compressor 6. The liquid oxygen at the bottom of the oxygen-liquid separator 13 enters the liquid oxygen storage tank 15 for storage as liquid oxygen product.

[0048] S4. During off-peak and non-off-peak electricity periods, the nitrogen produced by the air separation unit 5 is compressed and pressurized by the nitrogen compressor 7, then enters the gas heat exchanger 10 through the nitrogen cooler 9. After exchanging heat with the oxygen and nitrogen from the oxygen-liquid separator 13 and the nitrogen-liquid separator 14, it enters the oxygen-nitrogen liquefaction unit 4 and liquid air for heat exchange and liquefaction before entering the nitrogen expander 12. After that, it enters the nitrogen-liquid separator 14. The nitrogen in the upper part of the nitrogen-liquid separator 14 is reheated by the gas heat exchanger 10 and then returns to the inlet of the nitrogen compressor 7. The liquid nitrogen at the bottom of the nitrogen-liquid separator 14 enters the liquid nitrogen storage tank 16 for storage as liquid nitrogen product.

[0049] Example 2

[0050] like Figure 2 The conventional air liquefaction unit 1, liquid air storage tank 2, liquid air pump 3, conventional air separation unit 5, nitrogen compressor 7, nitrogen cooler 9, gas heat exchanger 10, nitrogen expander 12, nitrogen gas-liquid separator 14, liquid oxygen storage tank 15, liquid nitrogen storage tank 16, nitrogen liquefaction unit 17, liquid air expander 18, regenerative heat exchanger 19, air compressor 20, and air purifier 21 are arranged according to the flow diagram. The air separation unit is an internal compression air separation unit.

[0051] Air compressor 20 is connected to air purifier 21. Air purifier 21 is connected to air inlet I of regenerative heat exchanger 19. Air outlet I of regenerative heat exchanger 19 is connected to conventional air liquefaction unit 1. The outlet of air liquefaction unit 1 is connected to liquid air storage tank 2. The outlet of liquid air storage tank 2 is connected to the lower tower liquid air inlet of air separation unit 5 and the air inlet of liquid air expander 18 via liquid air pump 3. The air outlet of liquid air expander 18 is connected to the air inlet of nitrogen liquefaction unit 17. The air outlet of nitrogen liquefaction unit 17 is connected to the air inlet of gas heat exchanger 10. The air outlet of gas heat exchanger 10 is connected to air inlet II of regenerative heat exchanger 19. Air outlet II of regenerative heat exchanger 19 is connected to the air inlet of air separation unit 5. The liquid oxygen outlet on the low-pressure side of the condenser-evaporator of unit 5 is connected to the liquid oxygen storage tank 15. The nitrogen outlet of the air separation unit 5 is connected to the nitrogen compressor 7. The outlet of the nitrogen compressor 7 is connected to the nitrogen inlet of the nitrogen cooler 9. The nitrogen outlet of the nitrogen cooler 9 is connected to the nitrogen inlet I of the gas heat exchanger 10. The nitrogen outlet I of the gas heat exchanger 10 is connected to the nitrogen inlet of the nitrogen liquefaction unit 17. The nitrogen (liquid nitrogen) outlet of the nitrogen liquefaction unit 17 is connected to the nitrogen expander 12. The nitrogen expander 12 is connected to the nitrogen-liquid separator 14. The gas outlet at the top of the nitrogen-liquid separator 14 is connected to the nitrogen inlet II of the gas heat exchanger 10. The nitrogen outlet II of the gas heat exchanger 10 is connected to the inlet of the nitrogen compressor 7. The liquid outlet at the bottom of the nitrogen-liquid separator 14 is connected to the liquid nitrogen storage tank 16.

[0052] The specific work process is as follows:

[0053] S1. During off-peak electricity periods, the air liquefaction system operates at full load. Ambient air is compressed and pressurized by air compressor 20, purified by air purifier 21 to remove moisture, carbon dioxide and nitrogen-hydrogen compounds, and then enters air liquefaction device 1 for liquefaction after recovering cold energy by cold storage heat exchanger 19. The liquefied air is stored in liquid air storage tank 2. The amount of air liquefied meets the raw material air needs of the air separation system throughout the day. The system stops operating during non-off-peak electricity periods.

[0054] S2. During off-peak and non-off-peak electricity periods, the liquid air pump 3 delivers liquid air from the liquid air storage tank 2, which is divided into two parts, A and B. Part A directly enters the lower tower of the conventional internal compression air separation unit 5. Part B is expanded and depressurized by the liquid air expander 18 and then enters the nitrogen liquefaction unit 17 for heat exchange with nitrogen. After recovering the cold energy through the cold storage heat exchanger 19, it enters the air separation unit 5 as the feed gas for air separation. Part B accounts for 17%-20% of the total air volume.

[0055] S3. During off-peak and non-off-peak electricity periods, the product oxygen produced by the air separation unit is drawn out in liquid form from the low-pressure side of the air separation unit's condenser-evaporator and stored in liquid oxygen storage tank 15 as liquid oxygen product.

[0056] S4. During off-peak and non-off-peak electricity periods, the nitrogen produced by the air separation unit 5 is compressed and pressurized by the nitrogen compressor 7, then enters the gas heat exchanger 10 through the nitrogen cooler 9 to exchange heat with the nitrogen from the top of the nitrogen-liquid separator 14, and then enters the nitrogen liquefaction unit 17 to exchange heat and liquefy liquid air before entering the nitrogen expander 12. After that, it enters the nitrogen-liquid separator 14. The nitrogen in the upper part of the nitrogen-liquid separator 14 is reheated by the gas heat exchanger 10 and then returns to the inlet of the nitrogen compressor 7. The liquid nitrogen at the bottom of the nitrogen-liquid separator 14 enters the liquid nitrogen storage tank 16 for storage as liquid nitrogen product.

[0057] The implementation of the process flow of this invention can achieve 100-105 MW / 10,000 Nm³. 3 The energy storage capacity of oxygen air separation production and 840 MWh / 10,000 Nm³ 3 Energy storage capacity for oxygen air separation production. The electricity cost for oxygen and nitrogen liquefaction is significantly lower than that of conventional liquefaction plants.

[0058] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A process for full liquidization of conventional air separation products based on liquid air energy storage, characterized in that, The process comprises: S1, during the valley electricity period, the air liquefaction device works at full load, the ambient air is compressed and pressurized by an air compressor, enters an air purifier to remove water, carbon dioxide and nitrogen hydrogen compounds, and then enters an air liquefaction device after recovering cold energy by a cold storage heat exchanger, is liquefied, and the liquefied air is stored in a liquid air storage tank, and the air liquefaction device stops running during the non-valley electricity period; S2, during the valley electricity period and the non-valley electricity period, the liquid air in the liquid air storage tank is transported into an oxygen-nitrogen liquefier by a liquid air pump, is heated with oxygen and nitrogen in the oxygen-nitrogen liquefier, then enters a gas heat exchanger for further heat exchange, and then enters a cold storage heat exchanger to recover the surplus cold energy of air, and finally enters an air separation device as raw gas for air separation; S3, the air entering the air separation device is separated in the air separation device to produce product oxygen and product nitrogen; S4, the product oxygen in step S3 is compressed and pressurized by an oxygen compressor, enters a gas heat exchanger to exchange heat with oxygen and nitrogen from an oxygen liquid separator and a nitrogen liquid separator, then enters an oxygen-nitrogen liquefier to exchange heat with liquid air, and finally enters an oxygen expander, and then enters an oxygen liquid separator; S5, the product nitrogen in step S3 is compressed and pressurized by a nitrogen compressor, enters a gas heat exchanger to exchange heat with oxygen and nitrogen from an oxygen liquid separator and a nitrogen liquid separator, then enters an oxygen-nitrogen liquefier to exchange heat with liquid air, and finally enters a nitrogen expander, and then enters a nitrogen liquid separator.

2. The all-liquid process for conventional air separation products based on liquid air energy storage according to claim 1, characterized in that, The amount of liquefied air produced by the air liquefaction device during the valley electricity period in step S1 and stored in the liquid air storage tank meets the needs of the air separation device for raw air supply throughout the day.

3. The all-liquid process for conventional air separation products based on liquid air energy storage according to claim 1, characterized in that, The oxygen at the upper part of the oxygen liquid separator is returned to the inlet of the oxygen compressor after being reheated by the gas heat exchanger, and the liquid oxygen at the bottom of the oxygen liquid separator is stored in a liquid oxygen storage tank as liquid oxygen product.

4. The all-liquid process for conventional air separation products based on liquid air energy storage according to claim 1, characterized in that, The nitrogen at the upper part of the nitrogen liquid separator is returned to the inlet of the nitrogen compressor after being reheated by the gas heat exchanger, and the liquid nitrogen at the bottom of the nitrogen liquid separator is stored in a liquid nitrogen storage tank as liquid nitrogen product.

5. The all-liquid process for conventional air separation products based on liquid air energy storage according to claim 1, characterized in that, The air liquefaction device and the air separation device are conventional air liquefaction devices and conventional air separation devices.

6. A process for full liquidization of conventional air separation products based on liquid air energy storage, characterized by, The process comprises: S1, during the valley electricity period, the air liquefaction device works at full load, the ambient air is compressed and pressurized by an air compressor, enters an air purifier to remove water, carbon dioxide and nitrogen hydrogen compounds, and then enters an air liquefaction device after recovering cold energy by a cold storage heat exchanger, is liquefied, and the liquefied air is stored in a liquid air storage tank, and the air liquefaction device stops running during the non-valley electricity period; S2, during the valley electricity period and the non-valley electricity period, the liquid air in the liquid air storage tank is transported into an oxygen-nitrogen liquefier by a liquid air pump, is heated with oxygen and nitrogen in the oxygen-nitrogen liquefier, then enters a gas heat exchanger for further heat exchange, and then enters a cold storage heat exchanger to recover the surplus cold energy of air, and finally enters an air separation device as raw gas for air separation; S3, the air entering the air separation device is separated in the air separation device to produce product oxygen and product nitrogen; S4, the product oxygen produced by the air separation device is introduced from the low-pressure side of the air separation device condenser-evaporator in a liquid state into a liquid oxygen storage tank as liquid oxygen product; S5, the product nitrogen gas produced by the air separation device is compressed by a nitrogen compressor, enters a gas heat exchanger through a nitrogen cooler, exchanges heat with nitrogen gas from the top of a nitrogen gas-liquid separator, enters a nitrogen liquefier and liquid air for heat exchange and liquefaction, and then enters a nitrogen expander, and is depressurized and enters the nitrogen gas-liquid separator.

7. The all-liquid process for conventional air separation products based on liquid air energy storage according to claim 6, characterized in that, The B part accounts for 17%-20% of the total amount of liquid air.

8. The all-liquid process for conventional air separation products based on liquid air energy storage according to claim 6, characterized in that, The nitrogen gas at the upper part of the nitrogen gas-liquid separator is returned to the inlet of the nitrogen compressor after being reheated by the gas heat exchanger, and the liquid nitrogen at the bottom of the nitrogen gas-liquid separator enters a liquid nitrogen storage tank as a liquid nitrogen product.

9. The all-liquid process for conventional air separation products based on liquid air energy storage according to claim 6, characterized in that, The air liquefaction device and the air separation device are conventional air liquefaction devices and conventional air separation devices.

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