Liquefied air energy storage based LNG cold energy utilization air separation process

Abstract

The application provides a liquefied air energy storage-based LNG cold energy utilization air separation process, and relates to the technical field of LNG cold energy utilization. The process stores cold energy in a cold storage heat exchanger when LNG is gasified, and during off-peak hours, an air liquefaction device absorbs cold energy from LNG storage through the cold storage heat exchanger, and uses low-cost electricity to liquefy air and store it. The liquid air is delivered by a liquid air pump, gasified, and used to liquefy air separation oxygen and nitrogen products. The gasified liquid air and air separation oxygen and nitrogen products are heat exchanged and reheated to serve as raw material air for the air separation device. The application can alleviate the problem of the impact of cold energy output fluctuations caused by LNG usage fluctuations on the stable production of the air separation device, and does not require any technical modification of the conventional air separation device. The application can realize the liquefaction of conventional air separation products using LNG cold energy and low-cost off-peak electricity, reduce the liquefaction cost of air separation device products, and realize large-scale and distributed energy storage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LNG cold energy utilization, in particular to a LNG cold energy utilization air separation process based on liquefied air energy storage. BACKGROUND

[0002] Liquefied natural gas (LNG) itself contains a large amount of cold energy, and the recycling of LNG cold energy has important economic value. One of the main ways of recycling LNG cold energy is to combine with a low-temperature air separation device, and the air separation device absorbs the gasification cold energy of LNG to reduce the power consumption of the air separation itself. However, the air separation device using LNG cold energy has a contradiction between the stable operation parameters required by the air separation and the unstable output of the LNG gasification cold energy, that is, the LNG cold energy output and the air separation cold absorption do not match. If this problem is not solved, the air separation will not be able to well utilize the cold energy of LNG gasification and maintain the stability of air separation production. SUMMARY

[0003] In order to solve the technical problem of the mismatch between the LNG cold energy output and the air separation cold absorption in the prior art, the present application provides a LNG cold energy utilization air separation process based on liquefied air energy storage. The technical solution is as follows:

[0004] A LNG cold energy utilization air separation process based on liquefied air energy storage, the process comprises:

[0005] S1, LNG from a LNG storage tank enters a LNG pump and then enters a LNG regenerative heat exchanger, the latent heat and sensible heat of gasification are stored in the regenerative medium of the LNG regenerative heat exchanger, and then the natural gas enters a natural gas pipeline system;

[0006] S2, air is sequentially compressed by an air compressor and purified by an air purifier, and then enters an air regenerative heat exchanger and a LNG regenerative heat exchanger, absorbs cold energy, and then enters an air liquefaction device, and the liquefied air is stored in a liquid air storage tank;

[0007] S3, the liquid air in the liquid air storage tank in step S2 is delivered into an oxygen-nitrogen condensing heat exchanger by a liquid air pump, exchanges heat with oxygen and nitrogen in the oxygen-nitrogen condensing heat exchanger, and then enters an air regenerative heat exchanger to recover the excess cold energy of air, and then enters an air separation device as raw material gas for air separation;

[0008] S4, the product oxygen produced by the air separation device in step S3 is compressed by an oxygen compressor, enters an oxygen cooler, and then enters a gas heat exchanger to exchange heat with oxygen and nitrogen from an oxygen gas-liquid separator and a nitrogen gas-liquid separator, and then enters an oxygen-nitrogen condensing heat exchanger, and then enters an oxygen expander to enter an oxygen gas-liquid separator, the oxygen in the upper part of the oxygen gas-liquid separator is heat-exchanged and reheated in the gas heat exchanger and then returns to the inlet of the oxygen compressor, and the liquid oxygen at the bottom of the oxygen gas-liquid separator is stored in a liquid oxygen storage tank as liquid oxygen product.

[0009] S5, the product nitrogen produced by the air separation device in step S3 is compressed by a nitrogen compressor, enters a nitrogen cooler, and then enters a gas heat exchanger after heat exchange with oxygen and nitrogen from an oxygen liquid separator and a nitrogen liquid separator, enters an oxygen-nitrogen condensation heat exchanger, and then enters a nitrogen liquid separator through a nitrogen expander, nitrogen at the upper part of the nitrogen liquid separator is returned to the inlet of the nitrogen compressor after heat exchange in the gas heat exchanger, and liquid nitrogen at the bottom of the nitrogen liquid separator enters a liquid nitrogen storage tank as a liquid nitrogen product.

[0010] The process in step S1 is performed during valley electricity period and non-valley electricity period.

[0011] The process in step S2 is performed during valley electricity period and stopped during non-valley electricity period.

[0012] The amount of air liquefied by the air liquefaction device in step S2 meets the requirement of the air separation system for raw material air throughout the day.

[0013] The processes in steps S3, S4 and S5 are performed during valley electricity period and non-valley electricity period.

[0014] The oxygen and nitrogen in step S3 come from the gas heat exchanger respectively.

[0015] The air separation device is a conventional air separation device.

[0016] The system on which the process relies includes a liquefied air energy storage system, an air separation device, an air separation oxygen-nitrogen product liquefaction system and an LNG cold storage heat exchange system,

[0017] The liquefied air energy storage system includes an air compressor, an air purifier, an air liquefaction device and a liquid air storage tank.

[0018] The air separation oxygen-nitrogen product liquefaction system includes an oxygen compressor, a nitrogen compressor, an oxygen cooler, a nitrogen cooler, a gas heat exchanger, an oxygen expander, a nitrogen expander, an oxygen liquid separator, a nitrogen liquid separator, a liquid oxygen storage tank and a liquid nitrogen storage tank.

[0019] The LNG cold storage heat exchange system includes an LNG storage tank, an LNG pump and an LNG cold storage heat exchanger.

[0020] The LNG storage tank is connected to the natural gas inlet of the LNG cold storage heat exchanger through the LNG pump, and the natural gas outlet of the LNG cold storage heat exchanger is connected to a natural gas pipeline network.

[0021] The air compressor inlet is connected with ambient air, the air compressor outlet is connected with an air purifier, the air purifier outlet is connected with an air inlet I of an air regenerative heat exchanger, the air outlet I of the air regenerative heat exchanger is connected with an air inlet of an LNG regenerative heat exchanger, and the air outlet of the LNG regenerative heat exchanger is connected with an air liquefaction device, and the air liquefaction device outlet is connected with a liquid air storage tank.

[0022] The liquid air storage tank outlet is connected with an air inlet of an oxygen-nitrogen condensing heat exchanger through a liquid air pump, the air outlet of the oxygen-nitrogen condensing heat exchanger is connected with an air inlet II of the air regenerative heat exchanger, and the air outlet II of the air regenerative heat exchanger is connected with an inlet of an air separation device.

[0023] The oxygen outlet of the air separation device is connected with an oxygen inlet of an oxygen cooler through an oxygen compressor, the oxygen outlet of the oxygen cooler is connected with an oxygen inlet I of a gas heat exchanger, the oxygen outlet I of the gas heat exchanger is connected with an oxygen inlet of an oxygen-nitrogen condensing heat exchanger, the oxygen outlet of the oxygen-nitrogen condensing heat exchanger is connected with an inlet of an oxygen-liquid separator through an oxygen expander, the upper gas outlet of the oxygen-liquid separator is connected with an oxygen inlet II of the gas heat exchanger, the oxygen outlet II of the gas heat exchanger is connected with an inlet of the oxygen compressor, and the bottom liquid outlet of the oxygen-liquid separator is connected with a liquid oxygen storage tank.

[0024] The nitrogen outlet of the air separation device is connected with a nitrogen inlet of a nitrogen cooler through a nitrogen compressor, the nitrogen outlet of the nitrogen cooler is connected with a nitrogen inlet I of a gas heat exchanger, the nitrogen outlet I of the gas heat exchanger is connected with a nitrogen inlet of an oxygen-nitrogen condensing heat exchanger, the nitrogen outlet of the oxygen-nitrogen condensing heat exchanger is connected with an inlet of a nitrogen-liquid separator through a nitrogen expander, the upper gas outlet of the nitrogen-liquid separator is connected with a nitrogen inlet II of the gas heat exchanger, the nitrogen outlet II of the gas heat exchanger is connected with an inlet of the nitrogen compressor, and the bottom liquid outlet of the nitrogen-liquid separator is connected with a liquid nitrogen storage tank.

[0025] The above system does not need to make any technical transformation and change to a conventional air separation system.

[0026] The oxygen compressor and the nitrogen compressor can be multi-stage compression and intermediate cooling.

[0027] The technical scheme provided by the embodiment of the application has at least the following beneficial effects:

[0028] The application combines the air liquefaction energy storage device and the air separation device using LNG cold energy, that is, the liquefied air energy storage system is arranged between the LNG gasification system and the air separation system, the air liquefaction system absorbs the cold energy released by the LNG, the air liquefaction system provides the stable raw material gas source for the air separation system and the cold energy required for the liquefaction of the air separation products, the air separation system has a stable operation environment and a large-scale energy storage function by using the LNG cold energy. In the off-peak period and the non-off-peak period, the cold energy generated by the LNG gasification is stored in the LNG cold storage heat exchanger, in the off-peak period, the liquefied air energy storage device absorbs the cold energy stored by the LNG gasification, and uses the low-cost electricity to liquefy and store the air, the liquefied air is gasified by the delivery liquefied air pump and the cold energy is used for the liquefaction of the air separation oxygen and nitrogen products, the liquefied air after the gasification and the air separation oxygen and nitrogen products are heat exchanged and reheated to be used as the raw material air for the air separation device. The application does not need to make any technical transformation to the air separation device, realizes the smooth combination between the fluctuation of the LNG cold energy release and the stability of the air separation requirement of the absorption of the LNG cold energy, and makes the LNG cold energy using air separation system have a large-scale energy storage function, so that the system operation stability is realized, the LNG cold energy is effectively used and the air separation product liquefaction electricity cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0030] Figure 1 It is a kind of air separation process flow chart based on liquefied air energy storage of LNG cold energy utilization provided by the embodiment of the application.

[0031] Wherein: 1-LNG storage tank; 2-LNG pump; 3-LNG cold storage heat exchanger; 4-air compressor; 5-air purifier; 6-air liquefaction device; 7-liquefied air storage tank; 8-liquefied air pump; 9-oxygen and nitrogen condensation heat exchanger; 10-air separation device; 11-gas heat exchanger; 12-oxygen compressor; 13-nitrogen compressor; 14-oxygen cooler; 15-nitrogen cooler; 16-oxygen expander; 17-nitrogen expander; 18-oxygen gas-liquid separator; 19-nitrogen gas-liquid separator; 20-liquid oxygen storage tank; 21-liquid nitrogen storage tank; 22-air cold storage heat exchanger. DETAILED DESCRIPTION

[0032] The technical solutions in the application will be described below with reference to the drawings.

[0033] In the embodiments of the present application, the words such as "example", "for example" and the like are used to represent an example, illustration or description. Any embodiment or design scheme described as "example" in the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the word "example" is intended to present the concept in a specific manner. In addition, in the embodiments of the present application, the meaning expressed by "and / or" can be both, or can be one of the two.

[0034] In the embodiments of the present application, sometimes the subscript such as W1 may be written in the form of non-subscript such as W1, and the meanings expressed thereby are consistent when the difference is not emphasized.

[0035] In order to make the technical problems, technical schemes and advantages to be solved by the present application more clear, the following will be described in detail in combination with the drawings and specific embodiments.

[0036] The embodiments of the present application provide a LNG cold energy utilization air separation process based on liquefied air energy storage. Figure 1 As shown in the flow chart of the LNG cold energy utilization air separation process based on air liquefaction energy storage, the process can include the following steps:

[0037] S1, LNG from the LNG storage tank 1 enters the LNG regenerative heat exchanger 3 through the LNG pump 2, stores the latent heat and sensible heat of gasification in the regenerative medium of the LNG regenerative heat exchanger 3, and then the natural gas enters the natural gas pipeline system;

[0038] S2, the air sequentially enters the air regenerative heat exchanger 22 and the LNG regenerative heat exchanger 3 after being compressed by the air compressor 4 and purified by the air purifier 5, absorbs the cold energy, enters the air liquefaction device 6, and the liquefied air is stored in the liquid air storage tank 7;

[0039] S3, the liquid air in the liquid air storage tank 7 in step S2 is delivered into the oxygen-nitrogen condensation heat exchanger 9 through the liquid air pump 8, enters the air regenerative heat exchanger 22 after heat exchange with oxygen and nitrogen in the oxygen-nitrogen condensation heat exchanger 9 to recover the excess cold energy of the air, and then enters the air separation device 10 as the raw material gas for air separation;

[0040] S4, the product oxygen gas produced by the air separation device 10 in step S3 is compressed and boosted by the oxygen compressor 12, enters the oxygen cooler 14, and then enters the gas heat exchanger 11 to exchange heat with oxygen and nitrogen from the oxygen gas liquid separator 18 and the nitrogen gas liquid separator 19, and then enters the oxygen-nitrogen condensation heat exchanger 9, and then enters the oxygen gas liquid separator 18 through the oxygen expander 16. The oxygen gas at the upper part of the oxygen gas liquid separator 18 is heat-exchanged and warmed up in the gas heat exchanger 11, and then returns to the inlet of the oxygen compressor 12. The liquid oxygen at the bottom of the oxygen gas liquid separator 18 enters the liquid oxygen storage tank 20 for storage as liquid oxygen product;

[0041] S5, the product nitrogen produced by the air separation device 10 in step S3 is compressed by the nitrogen compressor 13, enters the nitrogen cooler 15, and then enters the gas heat exchanger 11 to exchange heat with oxygen and nitrogen from the oxygen liquid separator 18 and the nitrogen liquid separator 19, and then enters the oxygen-nitrogen condensation heat exchanger 9, and then enters the nitrogen expander 17 and the nitrogen liquid separator 19, the nitrogen at the upper part of the nitrogen liquid separator 19 is reheated in the gas heat exchanger 11 and then returned to the inlet of the nitrogen compressor 13, and the liquid nitrogen at the bottom of the nitrogen liquid separator 19 is stored in the liquid nitrogen storage tank 21 as a liquid nitrogen product.

[0042] The process in step S1 is performed during the valley electricity period and the non-valley electricity period.

[0043] The process in step S2 is performed during the valley electricity period and stopped during the non-valley electricity period.

[0044] The amount of air liquefied in step S2 meets the requirement of the air separation system for raw air throughout the day.

[0045] The processes in steps S3, S4 and S5 are performed during the valley electricity period and the non-valley electricity period.

[0046] The oxygen and nitrogen in step S3 come from the gas heat exchanger 11.

[0047] The air separation device is a conventional air separation device.

[0048] The system on which the above process relies includes a liquefied air energy storage system, an air separation device, an air separation oxygen-nitrogen product liquefaction system, and an LNG cold storage heat exchange system,

[0049] The liquefied air energy storage system includes an air compressor 4, an air purifier 5, an air liquefaction device 6, and a liquid air storage tank 7.

[0050] The air separation oxygen-nitrogen product liquefaction system includes an oxygen compressor 12, a nitrogen compressor 13, an oxygen cooler 14, a nitrogen cooler 15, a gas heat exchanger 11, an oxygen expander 16, a nitrogen expander 17, an oxygen liquid separator 18, a nitrogen liquid separator 19, a liquid oxygen storage tank 20, and a liquid nitrogen storage tank 21.

[0051] The LNG cold storage heat exchange system includes an LNG storage tank 1, an LNG pump 2, and an LNG cold storage heat exchanger 3.

[0052] The LNG storage tank 1 is connected to the natural gas inlet of the cold storage heat exchanger 3 through the LNG pump, and the natural gas outlet of the LNG cold storage heat exchanger 3 is connected to the natural gas pipeline network.

[0053] The air compressor 4 is connected with the ambient air at the inlet, and the outlet of the air compressor 4 is connected with the air purifier 5, the outlet of the air purifier 5 is connected with the air inlet I of the air cold storage heat exchanger 22, the air outlet I of the air cold storage heat exchanger 22 is connected with the air inlet of the LNG cold storage heat exchanger 3, and the air outlet of the LNG cold storage heat exchanger 3 is connected with the air liquefaction device 6, and the outlet of the air liquefaction device 6 is connected with the liquid air storage tank 7.

[0054] The outlet of the liquid air storage tank 7 is connected with the air inlet of the oxygen-nitrogen condensing heat exchanger 9 through the liquid air pump 8, the air outlet of the oxygen-nitrogen condensing heat exchanger 9 is connected with the air inlet II of the air cold storage heat exchanger 22, and the air outlet II of the air cold storage heat exchanger 22 is connected with the air inlet of the air separation device 10.

[0055] The oxygen outlet of the air separation device 10 is connected with the oxygen inlet of the oxygen cooler 14 through the oxygen compressor 12, the oxygen outlet of the oxygen cooler 14 is connected with the oxygen inlet I of the gas heat exchanger 11, the oxygen outlet I of the gas heat exchanger 11 is connected with the oxygen inlet of the oxygen-nitrogen condensing heat exchanger 9, the oxygen outlet of the oxygen-nitrogen condensing heat exchanger 9 is connected with the inlet of the oxygen gas-liquid separator 18 through the oxygen expander 16, the upper gas outlet of the oxygen gas-liquid separator 18 is connected with the oxygen inlet II of the gas heat exchanger 11, the oxygen outlet II of the gas heat exchanger 11 is connected with the inlet of the oxygen compressor 12, and the bottom liquid outlet of the oxygen gas-liquid separator 18 is connected with the liquid oxygen storage tank 20.

[0056] The nitrogen outlet of the air separation device 10 is connected with the nitrogen inlet of the nitrogen cooler 15 through the nitrogen compressor 13, the nitrogen outlet of the nitrogen cooler 15 is connected with the nitrogen inlet I of the gas heat exchanger 11, the nitrogen outlet I of the gas heat exchanger 11 is connected with the nitrogen inlet of the oxygen-nitrogen condensing heat exchanger 9, the nitrogen outlet of the oxygen-nitrogen condensing heat exchanger 9 is connected with the inlet of the nitrogen gas-liquid separator 19 through the nitrogen expander 17, the upper gas outlet of the nitrogen gas-liquid separator 19 is connected with the nitrogen inlet II of the gas heat exchanger 11, the nitrogen outlet II of the gas heat exchanger 11 is connected with the inlet of the nitrogen compressor 15, and the bottom liquid outlet of the nitrogen gas-liquid separator 19 is connected with the liquid nitrogen storage tank 21.

[0057] In the actual working process, during the valley electricity period and the non-valley electricity period, the LNG cold storage heat exchange system works, the LNG from the LNG storage tank 1 enters the LNG cold storage heat exchanger 3 through the LNG pump 2, the latent heat and the sensible heat of gasification are stored in the cold storage medium of the LNG cold storage heat exchanger 3, and then the natural gas enters the natural gas pipeline system.

[0058] During the valley electricity period, the air is compressed by the air compressor 4 and purified by the air purifier 5, and then sequentially enters the air cold storage heat exchanger 22 and the LNG cold storage heat exchanger 3, absorbs cold energy, and then enters the air liquefaction device 6, and the liquefied air is stored in the liquid air storage tank 7; during the non-valley electricity period, the air compressor, the air purifier and the air liquefaction device stop working, and air liquefaction is not performed.

[0059] In the valley and non-valley, the liquid air in the liquid air tank 7 is delivered into the oxygen-nitrogen condensing heat exchanger 9 by the liquid air pump 8, and after heat exchange with oxygen and nitrogen, it enters the air storage heat exchanger to recover the surplus cold of air, and then enters the air separation device 10 as the raw gas for air separation, and the air separation device produces oxygen and nitrogen.

[0060] The produced oxygen is compressed and pressurized by the oxygen compressor 12 and cooled by the oxygen cooler 14, and then enters the gas heat exchanger 11 to exchange heat with oxygen and nitrogen from the oxygen gas-liquid separator 18 and the nitrogen gas-liquid separator 19, and then enters the oxygen-nitrogen condensing heat exchanger 9 to condense and liquefy, and then enters the oxygen gas-liquid separator 18 through the oxygen expander 16, and the oxygen gas at the upper part of the oxygen gas-liquid separator 18 is heat-exchanged and reheated in the gas heat exchanger 11 and then returned to the inlet of the oxygen compressor 12, and the liquid oxygen at the bottom of the oxygen gas-liquid separator 18 enters the liquid oxygen storage tank 20 as a liquid oxygen product for storage.

[0061] The produced nitrogen is compressed and pressurized by the nitrogen compressor 13 and cooled by the nitrogen cooler 15, and then enters the gas heat exchanger 11 to exchange heat with oxygen and nitrogen from the oxygen gas-liquid separator 18 and the nitrogen gas-liquid separator 19, and then enters the oxygen-nitrogen condensing heat exchanger 9 to condense and liquefy, and then enters the nitrogen gas-liquid separator 19 through the nitrogen expander 17, and the nitrogen gas at the upper part of the nitrogen gas-liquid separator 19 is heat-exchanged and reheated in the gas heat exchanger 11 and then returned to the inlet of the nitrogen compressor 13, and the liquid nitrogen at the bottom of the nitrogen gas-liquid separator 19 enters the liquid nitrogen storage tank 21 as a liquid nitrogen product for storage.

[0062] The implementation of the process flow of the present application can form 40-50MW / 10,000Nm 3 The energy storage power of the oxygen air separation capacity is 360MWh / 10,000Nm 3 The energy storage scale of the oxygen air separation capacity. The oxygen-nitrogen liquefaction electricity cost is significantly reduced compared with conventional liquefaction devices.

[0063] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A LNG cold energy utilization air separation process based on liquefied air energy storage, characterized in that, The process comprises: S1, LNG from the LNG storage tank enters the LNG regenerative heat exchanger through the LNG pump, and the latent heat of vaporization and sensible heat are stored in the regenerative medium of the LNG regenerative heat exchanger, and then the natural gas enters the natural gas pipeline system; S2, the air is compressed by the air compressor and purified by the air purifier, and then sequentially enters the air regenerative heat exchanger and the LNG regenerative heat exchanger, absorbs cold energy, and then enters the air liquefaction device, and the liquefied air is stored in the liquid air storage tank; S3, the liquid air in the liquid air storage tank in step S2 is transported into the oxygen-nitrogen condensing heat exchanger through the liquid air pump, and after heat exchange with oxygen and nitrogen in the oxygen-nitrogen condensing heat exchanger, it enters the air regenerative heat exchanger to recover the excess cold energy of the air, and then enters the air separation device as raw material gas for air separation; S4, the product oxygen produced by the air separation device in step S3 is compressed by the oxygen compressor and then enters the oxygen cooler, and then enters the gas heat exchanger to exchange heat with oxygen and nitrogen from the oxygen and nitrogen liquid separators, and then enters the oxygen-nitrogen condensing heat exchanger, and then enters the oxygen expander to enter the oxygen liquid separator, and the oxygen in the upper part of the oxygen liquid separator is heated and reheated in the gas heat exchanger and then returned to the inlet of the oxygen compressor, and the liquid oxygen at the bottom of the oxygen liquid separator is stored in the liquid oxygen storage tank as liquid oxygen product; S5, the product nitrogen produced by the air separation device in step S3 is compressed by the nitrogen compressor and then enters the nitrogen cooler, and then enters the gas heat exchanger to exchange heat with oxygen and nitrogen from the oxygen and nitrogen liquid separators, and then enters the oxygen-nitrogen condensing heat exchanger, and then enters the nitrogen expander to enter the nitrogen liquid separator, and the nitrogen in the upper part of the nitrogen liquid separator is heated and reheated in the gas heat exchanger and then returned to the inlet of the nitrogen compressor, and the liquid nitrogen at the bottom of the nitrogen liquid separator is stored in the liquid nitrogen storage tank as liquid nitrogen product.

2. The LNG cold energy utilization air separation process based on liquefied air energy storage of claim 1, wherein, The process in step S1 is carried out during the valley electricity period and the non-valley electricity period.

3. The LNG cold energy utilization air separation process based on liquefied air energy storage of claim 1, wherein, The process in step S2 is carried out during the valley electricity period and stopped during the non-valley electricity period.

4. The LNG cold energy utilization air separation process based on liquefied air energy storage of claim 1, wherein, The amount of air liquefied by the air liquefaction device in step S2 meets the full-day raw material air requirement of the air separation system.

5. The LNG cold energy utilization air separation process based on liquefied air energy storage of claim 1, wherein, The processes in steps S3, S4 and S5 are carried out during the valley electricity period and the non-valley electricity period.

6. The LNG cold energy utilization air separation process based on liquefied air energy storage of claim 1, wherein, The oxygen and nitrogen in step S3 come from the gas heat exchanger.

7. The LNG cold energy utilization air separation process based on liquefied air energy storage of claim 1, wherein, The air separation device is a conventional air separation device.

8. The LNG cold energy utilization air separation process based on liquefied air energy storage of claim 1, wherein, The system on which the process relies comprises a liquefied air energy storage system, an air separation device, an air separation oxygen-nitrogen product liquefaction system and an LNG regenerative heat exchange system, The liquefied air energy storage system comprises an air compressor, an air purifier, an air liquefaction device and a liquid air storage tank; The air separation oxygen-nitrogen product liquefaction system comprises an oxygen compressor, a nitrogen compressor, an oxygen cooler, a nitrogen cooler, a gas heat exchanger, an oxygen expander, a nitrogen expander, an oxygen liquid separator, a nitrogen liquid separator, a liquid oxygen storage tank and a liquid nitrogen storage tank; The LNG regenerative heat exchange system comprises an LNG storage tank, an LNG pump and an LNG regenerative heat exchanger.

9. The LNG cold energy utilization air separation process based on liquefied air energy storage of claim 8, wherein, The LNG storage tank is connected to the natural gas inlet of the LNG regenerative heat exchanger through the LNG pump, and the natural gas outlet of the LNG regenerative heat exchanger is connected to the natural gas pipeline system; The air compressor inlet is connected with ambient air, the air compressor outlet is connected with the air purifier, the air purifier outlet is connected with the air inlet I of the air cold storage heat exchanger, the air outlet I of the air cold storage heat exchanger is connected with the air inlet of the LNG cold storage heat exchanger, the air outlet of the LNG cold storage heat exchanger is connected with the air liquefaction device, and the air liquefaction device outlet is connected with the liquid air storage tank; The liquid air storage tank outlet is connected with the air inlet of the oxygen-nitrogen condensing heat exchanger through a liquid air pump, the air outlet of the oxygen-nitrogen condensing heat exchanger is connected with the air inlet II of the air cold storage heat exchanger, and the air outlet II of the air cold storage heat exchanger is connected with the air separation device inlet; The oxygen outlet of the air separation device is connected with the oxygen inlet of the oxygen cooler through an oxygen compressor, the oxygen outlet of the oxygen cooler is connected with the oxygen inlet I of the gas heat exchanger, the oxygen outlet I of the gas heat exchanger is connected with the oxygen inlet of the oxygen-nitrogen condensing heat exchanger, the oxygen outlet of the oxygen-nitrogen condensing heat exchanger is connected with the oxygen liquid separator inlet through an oxygen expander, the upper gas outlet of the oxygen liquid separator is connected with the oxygen inlet II of the gas heat exchanger, the oxygen outlet II of the gas heat exchanger is connected with the oxygen compressor inlet, and the bottom liquid outlet of the oxygen liquid separator is connected with the liquid oxygen storage tank; The nitrogen outlet of the air separation device is connected with the nitrogen inlet of the nitrogen cooler through a nitrogen compressor, the nitrogen outlet of the nitrogen cooler is connected with the nitrogen inlet I of the gas heat exchanger, the nitrogen outlet I of the gas heat exchanger is connected with the nitrogen inlet of the oxygen-nitrogen condensing heat exchanger, the nitrogen outlet of the oxygen-nitrogen condensing heat exchanger is connected with the nitrogen liquid separator inlet through a nitrogen expander, the upper gas outlet of the nitrogen liquid separator is connected with the nitrogen inlet II of the gas heat exchanger, the nitrogen outlet II of the gas heat exchanger is connected with the nitrogen compressor inlet, and the bottom liquid outlet of the nitrogen liquid separator is connected with the liquid nitrogen storage tank.

Images