Conventional air separation product all-liquification process based on liquid-air energy storage

Abstract

The invention provides a conventional air separation product all-liquification process based on liquid-air energy storage, and relates to the technical field of air separation energy storage. According to the process, in the off-peak electricity period, a liquefied air energy storage device liquefies and stores air through low-price electric energy, liquid air is conveyed and gasified through a liquid air pump, cold energy is used for liquefying an air separation oxygen and nitrogen product, and the gasified liquid air and the air separation oxygen and nitrogen product are subjected to heat exchange and reheating and then serve as raw material air to be supplied to an air separation device. The air liquefaction energy storage device and the air separation device do not need to be subjected to any technical transformation, it is guaranteed that air separation operation parameters are not affected by an energy storage and liquefaction system, conventional air separation products are liquefied through low-price off-peak electricity, and large-scale and distributed energy storage is achieved while the product liquefaction cost of the air separation device is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of air separation energy storage, and in particular to a full liquefaction process of conventional air separation products based on liquid air energy storage. Background Art

[0002] With the development of science and technology, society has an increasing demand for cryogenic liquid products, such as liquid nitrogen, liquid argon, and liquid oxygen. Currently, large-scale air separation units that produce oxygen, nitrogen, and argon on a large scale produce primarily gaseous products. Large-scale liquefaction of air separation products is not technically difficult, but it involves three issues: 1) Adaptive technical modifications to the air separation unit and air liquefaction energy storage device, especially the air separation unit, will involve the redevelopment of air separation process technology, requiring a significant investment of capital and time; 2) Air separation operating parameters must be maintained stable and unaffected by the energy storage and liquefaction systems; 3) Failure to adapt the air separation system to technical adaptation and the use of conventional gas liquefaction technology will lead to high electricity costs for liquefaction. Summary of the Invention

[0003] In order to solve the above technical problems existing in the prior art, the embodiment of the present invention provides a process for fully liquefying conventional air separation products based on liquid air energy storage. The technical solution is as follows:

[0004] A process for fully liquefying conventional air separation products based on liquid air energy storage, the process comprising:

[0005] S1. During off-peak periods, the air liquefaction unit operates at full capacity. Ambient air is compressed and boosted by the air compressor before entering the air purifier for purification to remove moisture, carbon dioxide, and nitrogen-hydrogen compounds. The air is then recovered through the cold storage heat exchanger and then enters the air liquefaction unit for liquefaction. The liquefied air is stored in the liquid air storage tank and stops operating during off-peak periods.

[0006] S2. During valley and non-valley periods, the liquid air in the liquid air storage tank is pumped into the oxygen-nitrogen liquefier via a liquid air pump. After exchanging heat with oxygen and nitrogen in the oxygen-nitrogen liquefier, the liquid air enters the gas heat exchanger for further heat exchange. It then enters the cold storage heat exchanger to recover excess cold energy before entering the air separation unit as feed 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, the product oxygen in step S3 is compressed and pressurized by the oxygen compressor, then enters the gas heat exchanger through the oxygen cooler to exchange heat with the oxygen and nitrogen from the oxygen-liquid separator and the nitrogen-liquid separator, then enters the oxygen-nitrogen liquefier to exchange heat with liquid air for liquefaction, then enters the oxygen expander, and then enters the oxygen-liquid separator;

[0009] S5. The product nitrogen in step S3 is compressed and pressurized by the nitrogen compressor, then enters the gas heat exchanger through the nitrogen cooler to exchange heat with the oxygen and nitrogen from the oxygen-liquid separator and the nitrogen-gas-liquid separator, then enters the oxygen-nitrogen liquefier to exchange heat with liquid air for liquefaction, then enters the nitrogen expander, and then enters the nitrogen-gas-liquid separator.

[0010] In step S1, the amount of liquefied air produced by the valley-period air liquefaction unit and stored in the liquid air storage tank satisfies the raw air supply needs of the air separation unit throughout the day.

[0011] The steps S2-S5 are performed during both valley period and non-valley period.

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

[0013] Among them, 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 from the low-pressure side of the condenser evaporator of the air separation unit in liquid form and enters the liquid oxygen storage tank for storage as liquid oxygen product;

[0015] The product nitrogen produced by the air separation unit is compressed and pressurized by the nitrogen compressor and then enters the gas heat exchanger through the nitrogen cooler. The product nitrogen exchanges heat with the nitrogen from the top of the nitrogen gas-liquid separator and then enters the nitrogen liquefier for heat exchange and liquefaction with liquid air. It then enters the nitrogen expander, expands and reduces the pressure, and then enters the nitrogen gas-liquid separator.

[0016] In the present invention, the oxygen at the top 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 enters the liquid oxygen storage tank and is stored as a liquid oxygen product.

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

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

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

[0020] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0021] The above scheme is based on the full liquefaction process of conventional air separation products using liquid air energy storage. During the valley power period, the liquefied air energy storage device uses low-cost electricity to liquefy and store the air. During the valley power period and non-valley power period, the liquid air is transported by the liquid air pump for vaporization and the cold is used to liquefy the air separation oxygen and nitrogen products. After the vaporization, the liquid air and the air separation oxygen and nitrogen products are heat-exchanged and then enter the cold storage heat exchanger to recover the excess cold of the air, which is then supplied to the air separation unit as raw air. The present invention does not require any technical transformation of the air liquefaction energy storage device and the air separation unit, and realizes the liquefaction of conventional air separation products using low-cost valley electricity. While reducing the liquefaction cost of the air separation unit products, it also realizes large-scale and distributed energy storage. The process of the present invention can provide technical support for the reuse of idle air separation units after replacement with new equipment in the metallurgical and chemical fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 This is a process flow chart for fully liquefying conventional air separation products based on liquid air energy storage provided by an embodiment of the present invention;

[0024] Figure 2 This is another form of a process flow chart for fully liquefying conventional air separation products based on liquid air energy storage provided in Example 2 of the present invention.

[0025] Among them: 1-air liquefaction device; 2-liquid air storage tank; 3-liquid air pump; 4-oxygen and nitrogen liquefier; 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-gas-liquid separator; 15-liquid oxygen storage tank; 16-liquid nitrogen storage tank; 17-nitrogen liquefier; 18-liquid air expander, 19-cold storage heat exchanger, 20-air compressor, 21-air purifier. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0027] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as an "exemplary" in the present invention should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner. Furthermore, in the embodiments of the present invention, "and / or" can mean both or either of the two.

[0028] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0029] The embodiment of the present invention provides a full liquefaction process of conventional air separation products based on liquid air energy storage. Figure 1 The process flow chart of fully liquefying conventional air separation products based on liquid air energy storage is shown. The process may include the following steps:

[0030] S1. During off-peak electricity periods, the air liquefaction unit 1 operates at full capacity. Ambient air is compressed and pressure-boosted by the air compressor 20 and then enters the air purifier 21 for purification to remove moisture, carbon dioxide, and nitrogen-hydrogen compounds. The air is then recovered by the cold storage heat exchanger 19 and then enters the air liquefaction unit 1 for liquefaction. The liquefied air is stored in the liquid air storage tank 2. Operation is stopped during off-peak electricity periods.

[0031] S2. During valley and non-valley periods, the liquid air in the liquid air storage tank 2 is transported by the liquid air pump 3 into the oxygen-nitrogen liquefier 4. After exchanging heat with oxygen and nitrogen in the oxygen-nitrogen liquefier 4, the liquid air enters the gas heat exchanger 10 for further heat exchange, then enters the cold storage heat exchanger 19 to recover excess cold energy, and then enters the air separation unit 5 as feed 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, the product oxygen in step S3 is compressed and pressurized by the oxygen compressor 6, then enters the gas heat exchanger 10 through the oxygen cooler 8, exchanges heat with the oxygen and nitrogen from the oxygen-liquid separator 13 and the nitrogen-liquid separator 14, then enters the oxygen-nitrogen liquefier 4, exchanges heat with liquid air, and then enters the oxygen expander 11, and then enters the oxygen-liquid separator 13;

[0034] S5. The product nitrogen in step S3 is compressed and pressurized by the nitrogen compressor 7, then enters the gas heat exchanger 10 through the nitrogen cooler 9, exchanges heat with the oxygen and nitrogen from the oxygen-liquid separator 13 and the nitrogen-gas-liquid separator 14, then enters the oxygen-nitrogen liquefier 4 for heat exchange and liquefaction with liquid air, then enters the nitrogen expander 12, and then enters the nitrogen-gas-liquid separator 14.

[0035] In step S1, the amount of liquefied air produced by the valley-period air liquefaction unit and stored in the liquid air storage tank 2 satisfies the raw air supply needs of the air separation unit throughout the day.

[0036] The oxygen at the top of the oxygen-liquid separator 13 is returned to the inlet of the oxygen compressor 6 after being reheated by the gas heat exchanger 10, and 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 returned to the inlet of the nitrogen compressor 7 after being reheated by the gas heat exchanger 10, and the liquid nitrogen at the bottom of the nitrogen gas-liquid separator 14 enters the liquid nitrogen storage tank 16 for storage as liquid nitrogen product.

[0038] The following describes this with reference to specific embodiments.

[0039] Example 1

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

[0041] The air compressor 20 is connected to the air purifier 21, the air purifier 21 is connected to the air inlet I of the cold storage heat exchanger 19, the air outlet I of the cold storage heat exchanger 19 is connected to the conventional air liquefaction device 1, the outlet of the conventional air liquefaction device 1 is connected to the liquid air storage tank 2, the outlet of the liquid air storage tank 2 is connected to the air inlet of the oxygen-nitrogen liquefier 4 via the liquid air pump 3, the air outlet of the oxygen-nitrogen liquefier 4 is connected to the air inlet of the gas heat exchanger 10, the air outlet of the gas heat exchanger 10 is connected to the air inlet II of the cold storage heat exchanger 19, and the air outlet II of the cold storage heat exchanger 19 is connected to the 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 liquefier 4, the oxygen outlet of the oxygen-nitrogen liquefier 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, and 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 liquefier 4, the nitrogen outlet of the oxygen-nitrogen liquefier 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 of the upper part 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, and the liquid outlet of the lower part of the nitrogen gas-liquid separator 13 is connected to the liquid nitrogen storage tank 16.

[0044] The specific working process is as follows:

[0045] S1. During off-peak periods, the conventional air liquefaction system operates at full capacity. Ambient air is compressed and pressure-boosted by air compressor 20, purified by air purifier 21 to remove moisture, carbon dioxide, and nitrogen-hydrogen compounds, and then enters air liquefaction unit 1 for liquefaction after recovering cold energy through cold storage heat exchanger 19. The liquefied air is stored in liquid air storage tank 2. The amount of liquefied air meets the daily feed air needs of the air separation system. Operation is stopped during off-peak periods.

[0046] S2. During off-peak and off-peak periods, the liquid air pump 3 delivers liquid air from the liquid air storage tank 2 into the oxygen-nitrogen liquefier 4. After exchanging heat with oxygen and nitrogen, the liquid air enters the gas heat exchanger 10 for further heat exchange. The air then enters the cold storage heat exchanger 19 to recover excess cold energy, and then enters the air separation unit 5 (including internal compression and external compression air separation units) as feed gas for air separation.

[0047] S3. During the valley power period and the non-valley power period, the product oxygen produced by the air separation unit 5 is compressed and pressurized by the oxygen compressor 6, and 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 liquefier 4 to exchange heat with liquid air for liquefaction, and then enters the oxygen expander 11, and then enters the oxygen-liquid separator 13. The oxygen at the top of the oxygen-liquid separator is reheated by the gas heat exchanger 10 and then 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 to be stored as liquid oxygen product.

[0048] S4. During the valley power period and the non-valley power period, the product 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, exchanges heat with the oxygen and nitrogen from the oxygen-liquid separator 13 and the nitrogen-gas-liquid separator 14, then enters the oxygen-nitrogen liquefier 4 for heat exchange and liquefaction with liquid air, then enters the nitrogen expander 12, and then enters the nitrogen-gas-liquid separator 14. The nitrogen 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 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 liquefier 17, liquid air expander 18, cold storage heat exchanger 19, air compressor 20, and air purifier 21 are arranged according to the flow chart. The air separation unit is an internal compression air separation unit.

[0051] The air compressor 20 is connected to the air purifier 21, the air purifier 21 is connected to the air inlet I of the cold storage heat exchanger 19, the air outlet I of the cold storage heat exchanger 19 is connected to the conventional air liquefaction device 1, the outlet of the air liquefaction device 1 is connected to the liquid air storage tank 2, the outlet of the liquid air storage tank 2 is connected to the lower tower liquid air inlet of the air separation device 5 and the air inlet of the liquid air expander 18 after passing through the liquid air pump 3, the air outlet of the liquid air expander 18 is connected to the air inlet of the nitrogen liquefier 17, the air outlet of the nitrogen liquefier 17 is connected to the air inlet of the gas heat exchanger 10, the air outlet of the gas heat exchanger 10 is connected to the air inlet II of the cold storage heat exchanger 19, the air outlet II of the cold storage heat exchanger 19 is connected to the air inlet of the air separation device 5, the air separation The liquid oxygen outlet on the low-pressure side of the condensing evaporator of the device 5 is connected to the liquid oxygen storage tank 15, the nitrogen outlet of the air separation device 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 liquefier 17, the nitrogen (liquid nitrogen) outlet of the nitrogen liquefier 17 is connected to the nitrogen expander 12, the nitrogen expander 12 is connected to the nitrogen gas-liquid separator 14, the gas outlet of the upper part 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, and the liquid outlet of the lower part of the nitrogen gas-liquid separator 14 is connected to the liquid nitrogen storage tank 16.

[0052] The specific working process is as follows:

[0053] S1. During off-peak periods, the air liquefaction system operates at full capacity. Ambient air is compressed and pressure-boosted by air compressor 20, purified by air purifier 21 to remove moisture, carbon dioxide, and nitrogen-hydrogen compounds, and then enters air liquefaction unit 1 for liquefaction after recovering cold energy through cold storage heat exchanger 19. The liquefied air is stored in liquid air storage tank 2. The amount of liquefied air meets the daily raw air needs of the air separation system. Operation is stopped during off-peak periods.

[0054] S2. During valley and non-valley periods, the liquid air pump 3 delivers liquid air from the liquid air storage tank 2 into two parts, A and B. Part A directly enters the lower tower of the conventional internal compression air separation unit 5, while part B is expanded and depressurized by the liquid air expander 18 and then enters the nitrogen liquefier 17 for heat exchange with nitrogen. After that, it recovers cold energy through the cold storage heat exchanger 19 and then 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 the valley power period and the non-valley power period, the product oxygen produced by the air separation is drawn out from the low-pressure side of the condenser evaporator of the air separation unit in liquid form and enters the liquid oxygen storage tank 15 for storage as liquid oxygen product;

[0056] S4. During the off-peak and off-peak periods, the product 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, exchanges heat with the nitrogen from the top of the nitrogen gas-liquid separator 14, then enters the nitrogen liquefier 17 for heat exchange and liquefaction with liquid air, then enters the nitrogen expander 12, and then enters the nitrogen gas-liquid separator 14. The nitrogen 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 liquid nitrogen product.

[0057] The implementation of the process of the present invention can form 100-105MW / 10,000Nm 3 The energy storage power of oxygen air separation capacity is 840MWh / 10,000Nm 3 The energy storage scale of oxygen air separation production capacity. The electricity cost of oxygen and nitrogen liquefaction is significantly lower than that of conventional liquefaction equipment.

[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 modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A full liquefaction process for conventional air separation products based on liquid air energy storage, characterized in that: The process comprises: S1. During off-peak periods, the air liquefaction unit operates at full capacity. Ambient air is compressed and boosted by the air compressor before entering the air purifier for purification to remove moisture, carbon dioxide, and nitrogen-hydrogen compounds. The air is then recovered through the cold storage heat exchanger and then enters the air liquefaction unit for liquefaction. The liquefied air is stored in the liquid air storage tank and stops operating during off-peak periods. S2. During valley and non-valley periods, the liquid air in the liquid air storage tank is pumped into the oxygen-nitrogen liquefier via a liquid air pump. After exchanging heat with oxygen and nitrogen in the oxygen-nitrogen liquefier, the liquid air enters the gas heat exchanger for further heat exchange. It then enters the cold storage heat exchanger to recover excess cold energy before entering the air separation unit as feed gas for air separation. S3, the air entering the air separation unit is separated in the air separation unit to produce product oxygen and product nitrogen; S4, the product oxygen in step S3 is compressed and pressurized by the oxygen compressor, then enters the gas heat exchanger through the oxygen cooler to exchange heat with the oxygen and nitrogen from the oxygen-liquid separator and the nitrogen-liquid separator, then enters the oxygen-nitrogen liquefier to exchange heat with liquid air for liquefaction, then enters the oxygen expander, and then enters the oxygen-liquid separator; S5. The product nitrogen in step S3 is compressed and pressurized by the nitrogen compressor, then enters the gas heat exchanger through the nitrogen cooler to exchange heat with the oxygen and nitrogen from the oxygen-liquid separator and the nitrogen-gas-liquid separator, then enters the oxygen-nitrogen liquefier to exchange heat with liquid air for liquefaction, then enters the nitrogen expander, and then enters the nitrogen-gas-liquid separator.

2. The full liquefaction process of conventional air separation products based on liquid air energy storage according to claim 1 is characterized in that: In step S1, the amount of liquefied air produced by the valley-period air liquefaction unit and stored in the liquid air storage tank satisfies the raw air supply needs of the air separation unit throughout the day.

3. The process for fully liquefying conventional air separation products based on liquid air energy storage according to claim 1, characterized in that: In step S2, the liquid air in the liquid air storage tank is transported by the liquid air pump and divided into two parts, A and B. Part A directly enters the liquid air inlet of the lower tower of the air separation unit, and part B enters the nitrogen liquefier after expansion and pressure reduction in the liquid air expander and heat exchange with nitrogen. Thereafter, it enters the cold storage heat exchanger through the gas heat exchanger to recover excess cold energy of the air, and finally enters the air separation unit as the feed gas for air separation.

4. The process for fully liquefying conventional air separation products based on liquid air energy storage according to claim 3, characterized in that: The B portion accounts for 17%-20% of the total liquid air volume.

5. The process for fully liquefying conventional air separation products based on liquid air energy storage according to claim 3, characterized in that: The product oxygen produced by the air separation unit is drawn out from the low-pressure side of the condenser evaporator of the air separation unit in liquid form and enters the liquid oxygen storage tank for storage as liquid oxygen product.

6. The process for fully liquefying conventional air separation products based on liquid air energy storage according to claim 3, characterized in that: The product nitrogen produced by the air separation unit is compressed and pressurized by the nitrogen compressor and then enters the gas heat exchanger through the nitrogen cooler. The product nitrogen exchanges heat with the nitrogen from the top of the nitrogen gas-liquid separator and then enters the nitrogen liquefier for heat exchange and liquefaction with liquid air. The nitrogen then enters the nitrogen expander, expands and reduces the pressure, and then enters the nitrogen gas-liquid separator.

7. The process for fully liquefying conventional air separation products based on liquid air energy storage according to claim 1, characterized in that: The oxygen at the top of the oxygen-liquid separator is reheated by the gas heat exchanger and then returned to the oxygen compressor inlet, and the liquid oxygen at the bottom of the oxygen-liquid separator enters the liquid oxygen storage tank and is stored as a liquid oxygen product.

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

9. The process for fully liquefying 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.

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