Energy storage system coupled with internal compression air separation system and energy storage and release method thereof

Abstract

The invention provides an energy storage system coupled with an internal compression air separation system, which comprises the internal compression air separation system, and a high-temperature cold energy storage system, a low-temperature cold energy storage system and a liquid air storage system which are additionally arranged in the internal compression air separation system, the high-temperature cold energy storage system comprises a high-temperature heat exchanger and two ethanol storage tanks; the high-temperature heat exchanger is provided with five high-temperature heat exchanger fluid heat exchange channels; the low-temperature cold energy storage system comprises a low-temperature heat exchanger and two propane storage tanks; the low-temperature heat exchanger is provided with four low-temperature heat exchanger fluid heat exchange channels; the liquid air storage system comprises a gas-liquid separator, a liquid air storage tank, a liquid air pump, a throttle valve and a liquid air subcooler; the liquid air subcooler is provided with two liquid air subcooler fluid heat exchange channels. Cold energy is stored in multiple temperature zones and multiple modes, and irreversible loss in the energy storage process is reduced.

Description

Technical Field

[0001] This invention relates to the fields of cold storage, liquefied air energy storage and air separation technology, and in particular to an energy storage system coupled with an internal compression air separation system and its energy storage and release methods. Background Technology

[0002] With the development of the market economy and the continuous expansion of electricity demand, the peak-valley difference in power supply has become more pronounced. The installed capacity of renewable energy power generation such as wind and solar power has been increasing year by year. By the end of 2023, wind and solar power generation accounted for 15.3% of the total electricity consumption, placing higher demands on the adaptability and frequency and voltage regulation capabilities of the power grid. To address these issues, developing large-scale energy storage technology has become a strategic goal of national energy technology development. Currently, commonly used large-scale physical energy storage technologies include pumped hydro storage, compressed air storage, and liquefied air storage. Pumped hydro storage and compressed air storage technologies are constrained by geographical location and site selection, limiting their development. However, liquefied air storage technology, due to its unique advantages such as high energy density, short response time, high safety factor, wide availability of raw materials, and lack of geographical and environmental limitations, is widely considered a promising large-scale energy storage method.

[0003] Air separation equipment is the core equipment for producing industrial gases, the "blood" of industry. From traditional industries like petrochemicals, coal mining, and steel to emerging industries like electronics, semiconductors, and biopharmaceuticals, there is a significant demand for industrial gases. In 2020, the total electricity consumption of air separation equipment in China reached 5.24% of the country's total electricity consumption (7.511 trillion kWh). As a single production unit, its electricity consumption is considerable. With my country's continued supply-side structural reform, traditional industries such as steel, metallurgy, and chemicals are gradually achieving capacity transformation and upgrading under the "three reductions, one lowering, and one supplement" policy. With the industrial scale and integrated layout of traditional industries such as coal chemical and oil refining projects, outdated production capacity is gradually being eliminated. Therefore, the metallurgical air separation industry generally faces multiple crises such as production reduction, shutdowns, and equipment idleness. Air separation equipment in some chemical fields is also generally operating at reduced loads, resulting in designed capacity generally exceeding actual gas demand and serious air separation gas dissipation. Therefore, if large-scale energy storage technology can be implemented using air separation equipment, it will be of great significance for improving the current situation of oversupply in air separation equipment processes and saving investment costs for energy storage systems.

[0004] Due to the compatibility of air separation and liquefied air energy storage technologies in terms of cooling temperature range and equipment utilization, choosing to use air separation process equipment to achieve large-scale storage of liquefied air can not only reduce the amount of equipment used and the production, operation, and maintenance costs of the equipment, but also fully tap the operating potential of air separation equipment, reduce the amount of product gas emitted from the air separation system, improve equipment utilization, and realize the large-scale, ultra-large-scale, multi-functional, and integrated development of air separation equipment and process technology.

[0005] The air separation unit is integrated with the liquefied air energy storage system. Without affecting the normal operation of the air separation unit, the compression, cooling and purification equipment in the air separation system can be shared with the liquefied air energy storage system.

[0006] Existing technologies, such as Chinese invention patent applications CN113670003A, CN113686099A, CN112145248A, CN111043833A, and CN111811213A, propose liquefied air energy storage integrated systems for internal / external compressed air separation systems. These integrated systems utilize low-cost off-peak electricity to store externally supplied air in liquid form in cryogenic storage tanks, beyond the product user's load demand. During peak or off-peak electricity periods, the stored cryogenic liquid air is used to recover high-grade cold energy through heat exchange equipment, and then outputs electrical energy through a turbine expansion power generation device, while recovering all the cryogenic pure air output from the expansion.

[0007] Thermodynamic analysis of the above process flow reveals that the main reasons for the low system efficiency are: using only liquefied air as the energy storage medium, there is excess cooling in a certain temperature range during the energy storage / release process of the air separation process; under the energy release condition, the liquefied air is pressurized and heated by a higher temperature gas flow, then expanded by an expander to generate electricity, and enters the distillation column as gaseous components. When the liquefied air vaporizes, the fluid temperature ranges on both sides of the heat exchanger are difficult to match, resulting in additional irreversible losses and reducing system efficiency; in addition, the energy release process is also limited by the efficiency of the expander, resulting in low "electricity-cooling-electricity" conversion efficiency. Summary of the Invention

[0008] This invention provides an energy storage system and its energy storage and release method for a coupled internal compression air separation system, in order to solve the technical problem that in the existing air separation process, there is excess cold in a certain temperature zone during energy storage / release and heat exchange in the main heat exchanger, and the temperature zones of the fluids on both sides of the heat exchanger are difficult to match during liquid air vaporization under the energy release condition, resulting in additional irreversible losses.

[0009] The technical solution provided by this invention is as follows:

[0010] One object of the present invention is to provide an energy storage system coupled with an internal compression air separation system, the energy storage system comprising an internal compression air separation system, and a high-temperature cold energy storage system, a low-temperature cold energy storage system and a liquid air storage system added to the internal compression air separation system;

[0011] The internal compression air separation system includes an air booster system, a precooling and purification system, a main heat exchanger, and a distillation system; the air booster system includes at least an air compressor, a first booster, a first cooler, a second booster, a second cooler, a third booster, a third cooler, and an expander;

[0012] The high-temperature cold energy storage system includes a high-temperature heat exchanger and two ethanol storage tanks; the high-temperature heat exchanger has five high-temperature heat exchanger fluid heat exchange channels.

[0013] The cryogenic cold energy storage system includes a cryogenic heat exchanger and two propane storage tanks; the cryogenic heat exchanger has four cryogenic heat exchanger fluid heat exchange channels;

[0014] The liquid air storage system includes a gas-liquid separator, a liquid air tank, a liquid air pump, a throttle valve, and a liquid air subcooler; the liquid air subcooler has two liquid air subcooler fluid heat exchange channels;

[0015] The first high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger is connected at one end to the third cooler and at the other end to the expander.

[0016] The second high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger is connected at one end to the second cooler and at the other end to the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger.

[0017] One end of the third high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger is connected to the purification system, and the other end is connected to the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger.

[0018] The third high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger is connected to one end of the purification system and also to the second cooler;

[0019] One end of the fourth high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger is connected to the precooling system, and the other end is connected to the third low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger.

[0020] The two ends of the fifth high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger are respectively connected to the two ethanol storage tanks.

[0021] Wherein, the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger is connected to the first liquid-air subcooler fluid heat exchange channel of the liquid-air subcooler; the first liquid-air subcooler fluid heat exchange channel of the liquid-air subcooler is connected to the throttle valve, and the throttle valve is connected to the gas-liquid separator.

[0022] The second cryogenic heat exchanger fluid heat exchange channel of the cryogenic heat exchanger is connected to the second liquid-air subcooler fluid heat exchange channel of the liquid-air subcooler and the expander;

[0023] The second liquid air subcooler fluid heat exchange channel of the liquid air subcooler is connected to the top of the gas-liquid separator, and the bottom of the gas-liquid separator is connected to the liquid air storage tank; the liquid air storage tank is connected to the liquid air pump; the liquid air pump is connected to the distillation system;

[0024] The third low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger is connected to the nitrogen-sludge pipeline between the main heat exchanger and the distillation system.

[0025] The two ends of the fourth low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger are respectively connected to the two propane storage tanks.

[0026] In a preferred embodiment, the cold storage medium of the ethanol storage tank of the high-temperature cold energy storage system and the propane storage tank of the low-temperature cold energy storage system is a single or mixed fluid of methanol, ethanol, methane, propane, butane, and carbon dioxide, or a solid particle bed cold storage is used.

[0027] Another object of the present invention is to provide an energy storage method for an energy storage system coupled with an internal compression air separation system. During off-peak electricity periods, the energy storage system provided by the present invention is used for energy storage, comprising the following methods:

[0028] The air pressurization system of the internal compression air separation system experiences an increased operating load, while the main heat exchanger and distillation system maintain unchanged operating conditions.

[0029] The increased airflow from the third booster is led out through the third cooler, enters the fluid heat exchange channel of the first high-temperature heat exchanger of the high-temperature heat exchanger for cooling, and then is introduced into the expander to obtain low-temperature air.

[0030] Low-temperature air enters the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger and exchanges heat with the second air flow rate in the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger.

[0031] After passing through the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger, the low-temperature air enters the third high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger, where it exchanges heat with the first air flow rate in the first high-temperature heat exchanger fluid heat exchange channel and the second air flow rate in the second high-temperature heat exchanger fluid heat exchange channel. After heat exchange, the low-temperature air returns to the first booster compressor to be compressed into a high-pressure airflow.

[0032] The second air flow increased by the second booster is led out through the second cooler and enters the fluid heat exchange channel of the second high temperature heat exchanger of the high temperature heat exchanger, where it exchanges heat and cools with the counterflow low temperature air and counterflow gaseous air in the fluid heat exchange channel of the third high temperature heat exchanger of the high temperature heat exchanger.

[0033] After heat exchange and cooling, the second air flow enters the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger, and exchanges heat and cools with the counterflow low-temperature air and counterflow gaseous air in the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger.

[0034] After cooling, the second gas flow enters the first liquid-air subcooler fluid heat exchange channel of the liquid-air subcooler for further cooling, and then passes through the throttling valve for liquefaction.

[0035] After throttling and liquefaction, the second gas flow rate enters the gas-liquid separator; the liquid air generated by the second gas flow rate in the gas-liquid separator enters the liquid air storage tank from the bottom of the gas-liquid separator, and the gaseous air generated by the second gas flow rate in the gas-liquid separator enters the second liquid air subcooler fluid heat exchange channel from the top of the gas-liquid separator.

[0036] The gaseous air in the second liquid-air subcooler fluid heat exchange channel of the liquid-air subcooler enters the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger and exchanges heat with the second gas flow in the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger.

[0037] After heat exchange, gaseous air enters the third high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger and exchanges heat with the second gas flow rate in the second high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger, as well as the first gas flow rate in the first high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger.

[0038] After heat exchange, the gaseous air returns to the first booster and is compressed to form a high-pressure airflow.

[0039] In a preferred embodiment, the first gas flow rate in the first high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger exchanges heat and cools the reflux low-temperature air in the third high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger and the reflux gaseous air in the liquid air subcooler.

[0040] The first gas flow rate in the first high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger exchanges heat with the ethanol flow stream in the fifth high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger.

[0041] In a preferred embodiment, the second gas flow rate in the second high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger exchanges heat with the ethanol flow stream in the fifth high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger for cooling.

[0042] The second gas flow rate in the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger exchanges heat with the counterflow low-temperature air, counterflow gaseous air and propane stream in the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger.

[0043] In a preferred embodiment, the ratio of the first air flow rate to the second air flow rate is the same as the original ratio of the first air flow rate to the second air flow rate in the internal compression air separation system.

[0044] The temperature of the second gas flow rate entering the gas-liquid separator after throttling and liquefaction is the same as the temperature of the original throttling gas in the internal compression air separation system.

[0045] Another object of the present invention is to provide an energy release method for an energy storage system coupled with an internal compression air separation system. During peak power periods, the energy storage system coupled with an internal compression air separation system provided by the present invention is used for energy release, including the following method:

[0046] The air pressurization system and main heat exchanger of the internal compression air separation system are operated at reduced load, while the distillation system maintains its operating conditions.

[0047] Liquid air is drawn from the liquid air storage tank, pressurized by the liquid air pump, and then enters the distillation system;

[0048] The insufficient low-pressure air in the lower column of the distillation column is drawn by the purification system and directly enters the main heat exchanger for heat exchange. After being cooled by the cold energy of the reflux product, it directly enters the lower column of the distillation column.

[0049] After the main heat exchanger is operated at reduced load, the excess waste nitrogen flows sequentially through the third low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger and the fourth high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger for staged recovery of excess cold energy, and is stored in two propane storage tanks and two ethanol storage tanks respectively.

[0050] The excess nitrogen from the cascade recovery of surplus cooling capacity is returned to the precooling system.

[0051] In a preferred embodiment, the temperature of the low-pressure air is the same as the original temperature of the low-pressure air in the internal compression air separation system; the temperature of the liquid air is the same as the original temperature of the liquid air in the internal compression air separation system.

[0052] The total volume of low-pressure air entering the distillation system remains unchanged from the original total volume of low-pressure air entering the distillation system from the internal compression air separation system.

[0053] The total volume of liquid air entering the distillation system remains unchanged from the original total volume of liquid air entering the distillation system from the internal compression air separation system.

[0054] The liquefaction rate of the liquid air entering the distillation system remains unchanged from the original liquefaction rate of the liquid air entering the distillation system from the internal compression air separation system.

[0055] The above-described technical solution of the present invention has at least the following beneficial effects compared with the prior art:

[0056] This invention provides an energy storage system coupled with an internal compression air separation system and its energy storage and release method. With the goal of improving the energy storage scale and energy storage efficiency of the energy storage system, and combined with the characteristics of the air separation process, it uses liquid air, propane, ethanol and other energy storage media to store cold energy in multiple temperature zones and in multiple ways, thereby reducing irreversible losses in the energy storage and peak shaving process of the system.

[0057] This invention provides an energy storage system coupled with an internal compression air separation system and its energy storage and release method. A high-temperature cold energy storage system, a low-temperature cold energy storage system, and a liquid air storage system are coupled with the internal compression air separation system. By combining the internal compression air separation system with liquefied air energy storage technology, the design load surplus of the original internal compression air separation system is utilized, saving the amount of equipment used and achieving the goal of saving initial investment costs.

[0058] This invention provides an energy storage system coupled with an internal compression air separation system, and its energy storage and release methods. During energy storage and release, the operating conditions of the distillation system remain unchanged, without affecting oxygen and nitrogen production capacity and purity. Under energy release conditions, liquid air is directly pumped into the distillation column as a distillation feedstock. The liquid air does not need to undergo vaporization and expansion, thus improving the efficiency of liquid air utilization.

[0059] This invention provides an energy storage system coupled with an internal compression air separation system and its energy storage and release method. The high-temperature cold energy storage system, low-temperature cold energy storage system, and liquid air storage system store / release cold energy in different temperature ranges. That is, through the cascade storage of cold energy, it can match the requirements of the air separation process, reduce irreversible losses of the system, and improve energy storage efficiency. Attached Figure Description

[0060] 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.

[0061] Figure 1 This is a schematic diagram of the structure of a conventional internal compression air separation system in existing technology.

[0062] Figure 2 This is a schematic diagram of the energy storage system of a coupled internal compression air separation system according to the present invention.

[0063] Explanation of reference numerals in the attached figures:

[0064] 101. Air compressor; 102. First booster compressor; 104. Second booster compressor; 106. Third booster compressor; 103. First cooler; 105. Second cooler; 107. Third cooler; 108. Expander; 109. Main heat exchanger; 110. Liquid oxygen pump; 111. Lower column of distillation column; 112. Main cooler of distillation column; 113. Upper column of distillation column; 114. Subcooler of distillation column; 115. Distillation throttling valve;

[0065] A101, High-temperature heat exchanger; A102, Ethanol storage tank; A103, Low-temperature heat exchanger; A104, Propane storage tank; A105, Gas-liquid separator; A106, Liquid air storage tank; A107, Liquid air pump; A108, Throttling valve; A109, Liquid air subcooler;

[0066] G1, fluid heat exchange channel of the first high-temperature heat exchanger; G2, fluid heat exchange channel of the second high-temperature heat exchanger; G3, fluid heat exchange channel of the third high-temperature heat exchanger; G4, fluid heat exchange channel of the fourth high-temperature heat exchanger; G5, fluid heat exchange channel of the fifth high-temperature heat exchanger.

[0067] D1, fluid heat exchange channel of the first low-temperature heat exchanger; D2, fluid heat exchange channel of the second low-temperature heat exchanger; D3, fluid heat exchange channel of the third low-temperature heat exchanger; D4, fluid heat exchange channel of the fourth low-temperature heat exchanger.

[0068] K1, fluid heat exchange channel of the first liquid-air subcooler; K2, fluid heat exchange channel of the second liquid-air subcooler;

[0069] Q1, First air flow rate; Q2, Second air flow rate; Q3, Low-pressure air; Q4, Liquid air. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0071] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising,” “including,” or “including,” and similar terms mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or “connected,” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0072] It should be noted that the terms "up", "down", "left", "right", "front", and "back" used in this invention are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0073] Combination Figure 1 and Figure 2 According to an embodiment of the present invention, an energy storage system coupled with an internal compression air separation system is provided, including an internal compression air separation system, and a high-temperature cold energy storage system, a low-temperature cold energy storage system and a liquid air storage system added to the internal compression air separation system.

[0074] The internal compression air separation system is a conventional internal compression air separation system, such as... Figure 1 As shown. Comparison Figure 1 and Figure 2 The present invention adds a high-temperature cold energy storage system, a low-temperature cold energy storage system and a liquid air storage system to the internal compression air separation system.

[0075] According to an embodiment of the present invention, the internal compression air separation system includes an air booster system, a precooling system, a purification system, a main heat exchanger 109, and a distillation system. The air booster system includes an air compressor 101, a first booster compressor 102, a first cooler 103, a third booster compressor 106, a third cooler 107, a second booster compressor 104, a second cooler 105, and an expander 108.

[0076] Air compressor 101 is connected to a precooling system, the precooling system is connected to a purification system, the purification system is connected to a first booster compressor 102, and the first booster compressor 102 is connected to a first cooler 103.

[0077] The first cooler 103 is connected to the third booster 106 and the second booster 104. The third booster 106 is connected to the third cooler 107, and the third cooler 107 is connected to the main heat exchanger 109. The second booster 104 is connected to the second cooler 105, and the second cooler 105 is connected to the main heat exchanger 109. The main heat exchanger 109 is connected to the distillation system.

[0078] The third booster 106 is also connected to the expander 108, which is connected to the main heat exchanger 109 and the distillation system.

[0079] The distillation system includes a liquid oxygen pump 110, a lower column of the distillation column 111, a main cooler of the distillation column 112, an upper column of the distillation column 113, a subcooler of the distillation column 114, and a distillation throttling valve 115.

[0080] Furthermore, the expander 108 is connected to the lower column 111 of the distillation column, and one end of the liquid oxygen pump 110 is connected to the main heat exchanger 109, and the other end is connected to the main cooler 112 of the distillation column.

[0081] One end of the distillation throttle valve 115 is connected to the main heat exchanger 109, and the other end is connected to the lower column 111 of the distillation column. One end of the distillation subcooler 114 is connected to the upper column 113 of the distillation column, and the other end is connected to the lower column 111 of the distillation column, the main cooler 112 of the distillation column, and the main heat exchanger 109.

[0082] like Figure 2 As shown, according to an embodiment of the present invention, the high-temperature cold energy storage system includes a high-temperature heat exchanger A101 and two ethanol storage tanks A102. One ethanol storage tank A102 has a temperature of 25°C, and the other ethanol storage tank A102 has a temperature of -108°C.

[0083] The high-temperature heat exchanger A101 has five high-temperature heat exchanger fluid heat exchange channels, namely the first high-temperature heat exchanger fluid heat exchange channel G1, the second high-temperature heat exchanger fluid heat exchange channel G2, the third high-temperature heat exchanger fluid heat exchange channel G3, the fourth high-temperature heat exchanger fluid heat exchange channel G4, and the fifth high-temperature heat exchanger fluid heat exchange channel G5.

[0084] The cryogenic energy storage system includes a cryogenic heat exchanger A103 and two propane storage tanks A104. One propane storage tank A104 has a temperature of -108°C, and the other propane storage tank A104 has a temperature of -174°C.

[0085] The low-temperature heat exchanger A103 has four low-temperature heat exchanger fluid heat exchange channels, namely the first low-temperature heat exchanger fluid heat exchange channel D1, the second low-temperature heat exchanger fluid heat exchange channel D2, the third low-temperature heat exchanger fluid heat exchange channel D3, and the fourth low-temperature heat exchanger fluid heat exchange channel D4.

[0086] The liquid air storage system includes a gas-liquid separator A105, a liquid air storage tank A106, a liquid air pump A107, a throttle valve A108, and a liquid air subcooler A109.

[0087] The liquid-air subcooler A109 has two liquid-air subcooler fluid heat exchange channels, namely the first liquid-air subcooler fluid heat exchange channel K1 and the second liquid-air subcooler fluid heat exchange channel K2.

[0088] like Figure 2 As shown, according to an embodiment of the present invention, one end of the first high-temperature heat exchanger fluid heat exchange channel G1 of the high-temperature heat exchanger A101 is connected to the third cooler 107, and the other end is connected to the expander 108.

[0089] The first high-temperature heat exchanger fluid heat exchange channel G1 of the high-temperature heat exchanger A101 is a forward heat exchange channel, and the heat exchange fluid is high-pressure air.

[0090] One end of the second high-temperature heat exchanger fluid heat exchange channel G2 of the high-temperature heat exchanger A101 is connected to the second cooler 105, and the other end is connected to the first low-temperature heat exchanger fluid heat exchange channel D1 of the low-temperature heat exchanger A103.

[0091] The second high-temperature heat exchanger fluid heat exchange channel G2 of the high-temperature heat exchanger A101 is a forward heat exchange channel, and the heat exchange fluid is high-pressure air.

[0092] One end of the third high-temperature heat exchanger fluid heat exchange channel G3 of the high-temperature heat exchanger A101 is connected to the purification system, and the other end is connected to the second low-temperature heat exchanger fluid heat exchange channel D2 of the low-temperature heat exchanger A103.

[0093] The third high-temperature heat exchanger fluid heat exchange channel G3 of high-temperature heat exchanger A101 is a forward and counter-current heat exchange channel, and the heat exchange fluid is low-pressure air.

[0094] One end of the fourth high-temperature heat exchanger fluid heat exchange channel G4 of the high-temperature heat exchanger A101 is connected to the precooling system, and the other end is connected to the third low-temperature heat exchanger fluid heat exchange channel D3 of the low-temperature heat exchanger A103.

[0095] The fourth high-temperature heat exchanger fluid heat exchange channel G4 of high-temperature heat exchanger A101 is a counter-current heat exchange channel, and the heat exchange fluid is sludge nitrogen.

[0096] The two ends of the fifth high-temperature heat exchanger fluid heat exchange channel G5 of the high-temperature heat exchanger A101 are respectively connected to two ethanol storage tanks A102.

[0097] The fifth high-temperature heat exchanger fluid heat exchange channel G5 of high-temperature heat exchanger A101 is a forward and counter-current heat exchange channel, and the heat exchange fluid is ethanol.

[0098] like Figure 2 As shown, according to an embodiment of the present invention, the first low-temperature heat exchanger fluid heat exchange channel D1 of the low-temperature heat exchanger A103 is connected to the first liquid-air subcooler fluid heat exchange channel K1 of the liquid-air subcooler A109. The first liquid-air subcooler fluid heat exchange channel K1 of the liquid-air subcooler A109 is connected to the throttle valve A108, and the throttle valve A108 is connected to the gas-liquid separator A105.

[0099] The first low-temperature heat exchanger fluid heat exchange channel D1 of the low-temperature heat exchanger A103 is a forward heat exchange channel, and the heat exchange fluid is high-pressure air.

[0100] The first liquid-air subcooler fluid heat exchange channel K1 of the liquid-air subcooler A109 is a forward heat exchange channel, and the heat exchange gas is high-pressure air.

[0101] The second low-temperature heat exchanger fluid heat exchange channel D2 of the low-temperature heat exchanger A103 is connected to the second liquid-air subcooler fluid heat exchange channel K2 of the liquid-air subcooler A109 and the expander 108.

[0102] The second low-temperature heat exchanger fluid heat exchange channel D2 of the low-temperature heat exchanger A103 is a forward and counter-current heat exchange channel, and the heat exchange fluid is low-pressure air.

[0103] The second liquid-air subcooler fluid heat exchange channel K2 of the liquid-air subcooler A109 is a counter-current heat exchange channel, and the heat exchange gas is low-pressure air.

[0104] The second liquid air subcooler fluid heat exchange channel K2 of the liquid air subcooler A109 is connected to the top of the gas-liquid separator A105, and the bottom of the gas-liquid separator A105 is connected to the liquid air storage tank A106. The liquid air storage tank A106 is connected to the liquid air pump A107, and the liquid air pump A107 is connected to the distillation system. Specifically, the liquid air pump A107 is connected to the lower column 111 of the distillation column in the distillation system.

[0105] The third cryogenic heat exchanger fluid heat exchange channel D3 of cryogenic heat exchanger A103 connects the main heat exchanger 109 and the distillation system via a sludge nitrogen pipeline. Specifically, the third cryogenic heat exchanger fluid heat exchange channel D3 of cryogenic heat exchanger A103 connects the main heat exchanger 109 and the distillation subcooler 114 of the distillation system via a sludge nitrogen pipeline.

[0106] The two ends of the fourth cryogenic heat exchanger fluid heat exchange channel D4 of cryogenic heat exchanger A103 are respectively connected to two propane storage tanks A104.

[0107] The third low-temperature heat exchanger fluid heat exchange channel D3 of the low-temperature heat exchanger A103 is a counter-current heat exchange channel, and the heat exchange fluid is sludge nitrogen.

[0108] The fourth cryogenic heat exchanger fluid heat exchange channel D4 of cryogenic heat exchanger A103 is a forward and counter-current heat exchange channel, and the heat exchange fluid is propane.

[0109] In some embodiments, the cold storage medium of the ethanol storage tank A102 of the high-temperature cold energy storage system and the propane storage tank A104 of the low-temperature cold energy storage system is a single or mixed fluid of methanol, ethanol, methane, propane, butane, and carbon dioxide, or a solid particle bed cold storage is used.

[0110] like Figure 2 As shown in the embodiment of the present invention, an energy storage method for an energy storage system coupled with an internal compression air separation system is provided. During off-peak electricity hours at night, the energy storage system provided by the present invention is used for energy storage. Figure 2 The thick solid line represents the energy storage process.

[0111] Specifically, during off-peak electricity hours at night, energy storage is performed using an energy storage system coupled with an internal compression air separation system provided by this invention, including the following methods:

[0112] The air booster system (air compressor 101, first booster 102, first cooler 103, third booster 106, third cooler 107, second booster 104, second cooler 105 and expander 108) of the internal compression air separation system experiences an increased operating load, while the main heat exchanger 109 and the distillation system (liquid oxygen pump 110, lower distillation column 111, main distillation column cooler 112, upper distillation column 113, distillation subcooler 114 and distillation throttle valve 115) maintain unchanged operating conditions.

[0113] In this embodiment, the compressed air separation system is a 40,000 Nm³ / h air separation unit. 3 The conventional internal compression air separation process operates at 80% of its design load, meaning there is a surplus load. The first booster compressor 102, the third booster compressor 106, and the second booster compressor 104 are increased proportionally, resulting in increased compressed air flow. This increased airflow is drawn from before the main heat exchanger 109 and enters the added high-temperature cold energy storage system, low-temperature cold energy storage system, and liquid air storage system. The operation of the main heat exchanger 109 and the distillation system remains unaffected.

[0114] The first air flow rate Q1 increased by the third booster 106 is led out through the third cooler 107, enters the first high-temperature heat exchanger fluid heat exchange channel G1 of the high-temperature heat exchanger A101 for cooling, and then is introduced into the expander 108 to obtain low-temperature air.

[0115] Specifically, the first air flow rate Q1 in the first high-temperature heat exchanger fluid heat exchange channel G1 of the high-temperature heat exchanger A101 exchanges heat and cools with the counterflow low-temperature air in the third high-temperature heat exchanger fluid heat exchange channel G3 of the high-temperature heat exchanger A101 and the counterflow gaseous air in the liquid air subcooler A109 (the counterflow low-temperature air and the counterflow gaseous air are described in detail below).

[0116] Furthermore, the first gas flow rate Q1 in the first high-temperature heat exchanger fluid heat exchange channel G1 of the high-temperature heat exchanger A101 exchanges heat and cools with the ethanol flow in the fifth high-temperature heat exchanger fluid heat exchange channel G5 of the high-temperature heat exchanger A101.

[0117] Low-temperature air enters the second low-temperature heat exchanger fluid heat exchange channel D2 of the low-temperature heat exchanger A103 and exchanges heat with the high-pressure air with a second air flow rate Q2 (the second air flow rate Q2 will be described in detail below) in the first low-temperature heat exchanger fluid heat exchange channel D1 of the low-temperature heat exchanger A103.

[0118] After passing through the second low-temperature heat exchanger fluid heat exchange channel D2 of the low-temperature heat exchanger A103, the low-temperature air enters the third high-temperature heat exchanger fluid heat exchange channel G3 of the high-temperature heat exchanger A101, where it exchanges heat with the first air flow Q1 in the first high-temperature heat exchanger fluid heat exchange channel G1 of the high-temperature heat exchanger A101. The low-temperature air after heat exchange returns to the first booster 102 and is compressed to form a high-pressure airflow.

[0119] Simultaneously, the low-temperature air (obtained by the expander 108) enters the third high-temperature heat exchanger fluid heat exchange channel G3 of the high-temperature heat exchanger A101 and exchanges heat with the second gas flow rate Q2 (the second gas flow rate Q2 is described in detail below) in the second high-temperature heat exchanger fluid heat exchange channel G2 of the high-temperature heat exchanger A101. The low-temperature air after heat exchange returns to the first booster 102 and is compressed to form a high-pressure airflow.

[0120] The second air flow rate Q2, increased by the second booster 104, is led out through the second cooler 105 and enters the second high-temperature heat exchanger fluid heat exchange channel G2 of the high-temperature heat exchanger A101, where it exchanges heat and cools with the counterflow low-temperature air and counterflow gaseous air in the third high-temperature heat exchanger fluid heat exchange channel G3 of the high-temperature heat exchanger A101.

[0121] Furthermore, the second gas flow rate Q2 in the second high-temperature heat exchanger fluid heat exchange channel G2 of the high-temperature heat exchanger A101 exchanges heat and cools with the ethanol flow in the fifth high-temperature heat exchanger fluid heat exchange channel G5 of the high-temperature heat exchanger A101.

[0122] After heat exchange and cooling, the second air flow rate Q2 enters the first low-temperature heat exchanger fluid heat exchange channel D1 of the low-temperature heat exchanger A103, and exchanges heat and cools with the counterflow low-temperature air and counterflow gaseous air in the second low-temperature heat exchanger fluid heat exchange channel D2 of the low-temperature heat exchanger A103.

[0123] Furthermore, the second gas flow rate Q2 in the first low-temperature heat exchanger fluid heat exchange channel D1 of the low-temperature heat exchanger A103 exchanges heat and cools with the propane flow in the fourth low-temperature heat exchanger fluid heat exchange channel D4 of the low-temperature heat exchanger A103.

[0124] After cooling, the second gas flow rate Q2 enters the first liquid-air subcooler fluid heat exchange channel K1 of the liquid-air subcooler A109 for further cooling, and then undergoes throttling and liquefaction through the throttling valve A108.

[0125] After throttling and liquefaction, the second gas flow rate Q2 enters the gas-liquid separator A105. The liquid air generated by the second gas flow rate Q2 in the gas-liquid separator A105 enters the liquid air storage tank A106 from the bottom of the gas-liquid separator A105. The gaseous air generated by the second gas flow rate Q2 in the gas-liquid separator A105 enters the second liquid air subcooler fluid heat exchange channel K2 of the liquid air subcooler A109 from the top of the gas-liquid separator A105.

[0126] The gaseous air in the second liquid-air subcooler fluid heat exchange channel K2 of the liquid-air subcooler A109 enters the second low-temperature heat exchanger fluid heat exchange channel D2 of the low-temperature heat exchanger A103 and exchanges heat with the second gas flow rate Q2 in the first low-temperature heat exchanger fluid heat exchange channel D1 of the low-temperature heat exchanger A103.

[0127] After heat exchange, the gaseous air enters the third high-temperature heat exchanger fluid heat exchange channel G3 of the high-temperature heat exchanger A101, and exchanges heat with the second air flow Q2 in the second high-temperature heat exchanger fluid heat exchange channel G2 of the high-temperature heat exchanger A101, and the first air flow Q1 in the first high-temperature heat exchanger fluid heat exchange channel G1 of the high-temperature heat exchanger A101. After heat exchange, the gaseous air returns to the first booster 102 and is compressed to form a high-pressure airflow.

[0128] According to an embodiment of the present invention, the ratio of the first air flow rate Q1 and the second air flow rate Q2 is the same as the original ratio of the first air flow rate Q1 and the second air flow rate Q2 of the internal compression air separation system. That is, the ratio of the first air flow rate Q1 and the second air flow rate Q2 is the same as the original operating parameters of the internal compression air separation system.

[0129] The temperature of the second gas flow rate Q2 entering the gas-liquid separator A105 after throttling and liquefaction is the same as the original throttling gas temperature of the internal compression air separation system. That is, the temperature of the second gas flow rate Q2 entering the gas-liquid separator A105 after throttling and liquefaction is the same as the original operating parameters of the internal compression air separation system (the throttling gas temperature through the distillation throttling valve 115).

[0130] During the energy storage period of this invention, the air pressurization system operates under increased load, extracting cold energy from the high-temperature and low-temperature cold energy storage systems to increase the air liquefaction rate and the amount of liquefied air. During system energy storage, the liquid air storage system is in a cold energy storage state, while the high-temperature and low-temperature cold energy storage systems are in a cold energy release state. The insufficient cooling capacity of the high-temperature heat exchanger A101 and the low-temperature heat exchanger A103 is supplemented by the ethanol storage tank A102 and the propane storage tank A104.

[0131] During energy storage, the newly added high-temperature cold energy storage system, low-temperature cold energy storage system, and liquid air storage system liquefy air through the Kapitza cycle and store the air in the liquid air storage tank A106. The second gas flow rate Q2 in the ethanol storage tank A102 is cooled by cold energy through the fifth high-temperature heat exchanger fluid heat exchange channel G5 of the high-temperature heat exchanger A101, and the second gas flow rate Q2 in the propane storage tank A104 is cooled by cold energy through the fourth low-temperature heat exchanger fluid heat exchange channel D4 of the low-temperature heat exchanger A103, thereby increasing the Kapitza cycle liquefaction rate and obtaining more liquid air.

[0132] like Figure 2 As shown, according to an embodiment of the present invention, a method for releasing energy from an energy storage system coupled with an internal compression air separation system is provided. During peak power periods, energy is released using an energy storage system coupled with an internal compression air separation system provided by the present invention. Figure 2 The thick dashed line represents the energy release process.

[0133] Specifically, during peak daytime electricity periods, energy is released using an energy storage system coupled with an internal compression air separation system provided by this invention, including the following methods:

[0134] The air booster system (air compressor 101, first booster 102, first cooler 103, third booster 106, third cooler 107, second booster 104, second cooler 105 and expander 108) and main heat exchanger 109 of the internal compression air separation system operate at reduced load, while the distillation system (liquid oxygen pump 110, lower column of distillation column 111, main cooler of distillation column 112, upper column of distillation column 113, subcooler of distillation column 114 and distillation throttle valve 115) maintains the same operating conditions.

[0135] Liquid air Q4 is drawn from the liquid air storage tank A106, pressurized by the liquid air pump A107, and then enters the distillation system. Specifically, the liquid air Q4, after being pressurized by the liquid air pump A107, enters the lower column 111 of the distillation column in the distillation system.

[0136] The insufficient low-pressure air Q3 in the lower column 111 of the distillation column is drawn by the purification system and directly enters the main heat exchanger 109 for heat exchange. After being cooled by the cold energy of the reflux product, it directly enters the lower column 111 of the distillation column.

[0137] After the main heat exchanger 109 is operated at reduced load, the excess nitrogen in the nitrogen pipe between the main heat exchanger 109 and the distillation subcooler 114 of the distillation system flows sequentially through the third low-temperature heat exchanger fluid heat exchange channel D3 of the low-temperature heat exchanger A103 and the fourth high-temperature heat exchanger fluid heat exchange channel G4 of the high-temperature heat exchanger A101 for staged recovery of excess cooling capacity. The excess nitrogen is then stored in two propane storage tanks A104 and two ethanol storage tanks A102, respectively. The excess nitrogen after staged recovery is returned to the precooling system.

[0138] According to an embodiment of the present invention, the temperature of low-pressure air Q3 is the same as the original temperature of low-pressure air in the internal compression air separation system, that is, the temperature of low-pressure air Q3 is the same as the original operating parameters of the internal compression air separation system (the temperature of low-pressure air Q3 introduced by the purification system).

[0139] The temperature of liquid air Q4 is the same as the original temperature of liquid air in the internal compression air separation system, that is, the temperature of liquid air Q4 is the same as the original operating parameters of the internal compression air separation system (the temperature of liquid air after passing through the distillation throttle valve 115).

[0140] After the addition of a high-temperature cold energy storage system, a low-temperature cold energy storage system, and a liquid air storage system, the total amount of low-pressure air Q3 entering the distillation system remains unchanged compared to the original total amount of low-pressure air Q3 entering the distillation system from the internal compression air separation system.

[0141] After the addition of a high-temperature cold energy storage system, a low-temperature cold energy storage system, and a liquid air storage system, the total flow of liquid air Q4 entering the distillation system remains unchanged compared to the original flow of liquid air Q4 (liquid air Q4 passing through the distillation throttle valve 115) entering the distillation system from the internal compression air separation system.

[0142] The present invention adds a high-temperature cold energy storage system, a low-temperature cold energy storage system and a liquid air storage system. The liquefaction rate of the liquid air Q4 entering the distillation system remains unchanged from the original liquefaction rate of the liquid air (liquid air Q4 through the distillation throttle valve 115) entering the distillation system from the internal compressed air separation system.

[0143] During the energy release process of this invention, the total flow rate of liquid air Q4 entering the distillation system remains unchanged from the original flow rate of liquid air Q4 (liquid air Q4 through distillation throttle valve 115) entering the distillation system from the internal compression air separation system. The insufficient portion of liquid air Q4 (liquid air Q4 through distillation throttle valve 115) from the internal compression air separation system is directly pumped from the liquid air storage tank A106 into the lower column 111 of the distillation column by the liquid air pump A107.

[0144] During the energy release process of this invention, the total amount of low-pressure air Q3 entering the distillation system remains unchanged from the original total amount of low-pressure air Q3 entering the distillation system from the internal compression air separation system. The insufficient portion of gaseous air Q3 is extracted from the purification system and directly enters the main heat exchanger 109 for heat exchange. After being cooled by the cold energy of the reflux product, it directly enters the lower column 111 of the distillation column.

[0145] During the energy release process, due to the replenishment of liquid air Q4, there is a surplus of cold energy, which is stored in ethanol storage tank A102 and propane storage tank A104 according to temperature and grade.

[0146] This invention stores and retrieves cold energy according to different temperature zones, ensuring maximum system energy efficiency. Through thermodynamic calculations, the system achieves an electrical efficiency of over 90% when peak energy storage is less than 30%.

[0147] During the energy release period of this invention, the operating load of the air pressurization system is reduced, and the stored liquid air Q4 is replenished to the internal compression air separation system. The internal compression air separation system will have surplus cold energy, which is stored in temperature-zone-dependent cold energy storage systems A102 and A104. During the system's energy release period, the liquid air storage system is in a cold energy release state, while the high-temperature and low-temperature cold energy storage systems are in a cold energy storage state.

[0148] In a preferred embodiment, the high-temperature cold energy storage system and the low-temperature cold energy storage system of the present invention can be used individually or in combination.

[0149] The following points need to be explained:

[0150] (1) The accompanying drawings of the embodiments of the present invention only involve the structures involved in the embodiments of the present invention. Other structures can refer to the general design.

[0151] (2) For clarity, the thickness of layers or regions is enlarged or reduced in the drawings used to describe embodiments of the invention, i.e., these drawings are not drawn to scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being “above” or “below” another element, the element may be “directly” located “above” or “below” the other element or there may be intermediate elements.

[0152] (3) Where there is no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0153] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An energy storage system coupled with an internal compression air separation system, characterized in that, The energy storage system includes an internal compressed air separation system, and a high-temperature cold energy storage system, a low-temperature cold energy storage system, and a liquid air storage system added to the internal compressed air separation system. The internal compression air separation system includes an air booster system, a precooling and purification system, a main heat exchanger, and a distillation system; the air booster system includes at least an air compressor, a first booster, a first cooler, a second booster, a second cooler, a third booster, a third cooler, and an expander. The high-temperature cold energy storage system includes a high-temperature heat exchanger and two ethanol storage tanks; the high-temperature heat exchanger has five high-temperature heat exchanger fluid heat exchange channels. The cryogenic cold energy storage system includes a cryogenic heat exchanger and two propane storage tanks; the cryogenic heat exchanger has four cryogenic heat exchanger fluid heat exchange channels; The liquid air storage system includes a gas-liquid separator, a liquid air tank, a liquid air pump, a throttle valve, and a liquid air subcooler; the liquid air subcooler has two liquid air subcooler fluid heat exchange channels; The first high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger is connected at one end to the third cooler and at the other end to the expander. The second high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger is connected at one end to the second cooler and at the other end to the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger. One end of the third high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger is connected to the purification system, and the other end is connected to the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger. One end of the fourth high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger is connected to the precooling system, and the other end is connected to the third low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger. The two ends of the fifth high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger are respectively connected to the two ethanol storage tanks. Wherein, the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger is connected to the first liquid-air subcooler fluid heat exchange channel of the liquid-air subcooler; the first liquid-air subcooler fluid heat exchange channel of the liquid-air subcooler is connected to the throttle valve, and the throttle valve is connected to the gas-liquid separator. The second cryogenic heat exchanger fluid heat exchange channel of the cryogenic heat exchanger is connected to the second liquid-air subcooler fluid heat exchange channel of the liquid-air subcooler and the expander; The second liquid air subcooler fluid heat exchange channel of the liquid air subcooler is connected to the top of the gas-liquid separator, and the bottom of the gas-liquid separator is connected to the liquid air storage tank; the liquid air storage tank is connected to the liquid air pump; the liquid air pump is connected to the distillation system; The third low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger is connected to the nitrogen-sludge pipeline between the main heat exchanger and the distillation system. The two ends of the fourth low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger are respectively connected to the two propane storage tanks.

2. The energy storage system according to claim 1, characterized in that, The cold storage medium for ethanol storage tanks in high-temperature cold energy storage systems and propane storage tanks in low-temperature cold energy storage systems is a single or mixed fluid of methanol, ethanol, methane, propane, butane, and carbon dioxide, or solid particle bed cold storage is used.

3. An energy storage method for an energy storage system coupled with an internal compression air separation system, characterized in that, During off-peak electricity periods, energy storage is performed using the energy storage system described in any one of claims 1 to 2, comprising the following methods: The air pressurization system of the internal compression air separation system experiences an increased operating load, while the main heat exchanger and distillation system maintain unchanged operating conditions. The increased airflow from the third booster is led out through the third cooler, enters the fluid heat exchange channel of the first high-temperature heat exchanger of the high-temperature heat exchanger for cooling, and then is introduced into the expander to obtain low-temperature air. Low-temperature air enters the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger and exchanges heat with the second air flow rate in the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger. After passing through the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger, the low-temperature air enters the third high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger, where it exchanges heat with the first air flow rate in the first high-temperature heat exchanger fluid heat exchange channel and the second air flow rate in the second high-temperature heat exchanger fluid heat exchange channel. After heat exchange, the low-temperature air returns to the first booster compressor to be compressed into a high-pressure airflow. The second air flow increased by the second booster is led out through the second cooler and enters the fluid heat exchange channel of the second high temperature heat exchanger of the high temperature heat exchanger, where it exchanges heat and cools with the counterflow low temperature air and counterflow gaseous air in the fluid heat exchange channel of the third high temperature heat exchanger of the high temperature heat exchanger. After heat exchange and cooling, the second air flow enters the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger, and exchanges heat and cools with the counterflow low-temperature air and counterflow gaseous air in the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger. After cooling, the second gas flow enters the first liquid-air subcooler fluid heat exchange channel of the liquid-air subcooler for further cooling, and then passes through the throttling valve for liquefaction. After throttling and liquefaction, the second gas flow rate enters the gas-liquid separator; the liquid air generated by the second gas flow rate in the gas-liquid separator enters the liquid air storage tank from the bottom of the gas-liquid separator, and the gaseous air generated by the second gas flow rate in the gas-liquid separator enters the second liquid air subcooler fluid heat exchange channel from the top of the gas-liquid separator. The gaseous air in the second liquid-air subcooler fluid heat exchange channel of the liquid-air subcooler enters the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger and exchanges heat with the second gas flow in the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger. After heat exchange, gaseous air enters the third high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger and exchanges heat with the second gas flow rate in the second high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger, as well as the first gas flow rate in the first high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger. After heat exchange, the gaseous air returns to the first booster and is compressed to form a high-pressure airflow.

4. The energy storage method according to claim 3, characterized in that, The first gas flow rate in the first high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger exchanges heat and cools with the counterflow low-temperature air in the third high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger and the counterflow gaseous air in the liquid air subcooler. The first gas flow rate in the first high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger exchanges heat with the ethanol flow stream in the fifth high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger.

5. The energy storage method according to claim 3, characterized in that, The second gas flow rate in the second high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger exchanges heat and cools with the ethanol flow in the fifth high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger. The second gas flow rate in the first low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger exchanges heat with the counterflow low-temperature air, counterflow gaseous air and propane stream in the second low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger.

6. The energy storage method according to claim 3, characterized in that, The ratio of the first air flow rate to the second air flow rate is the same as the original ratio of the first air flow rate to the second air flow rate in the internal compression air separation system. The temperature of the second gas flow rate entering the gas-liquid separator after throttling and liquefaction is the same as the temperature of the original throttling gas in the internal compression air separation system.

7. A method for releasing energy from an energy storage system coupled with an internal compression air separation system, characterized in that, During peak power periods, energy release is performed using the energy storage system described in any one of claims 1 to 2, comprising the following methods: The air pressurization system and main heat exchanger of the internal compression air separation system are operated at reduced load, while the distillation system maintains its operating conditions. Liquid air is drawn from the liquid air storage tank, pressurized by the liquid air pump, and then enters the distillation system; The insufficient low-pressure air in the lower column of the distillation column is cooled by the main heat exchanger after passing through the purification system and then directly enters the lower column of the distillation column after being cooled by the cold energy of the reflux product. After the main heat exchanger is operated at reduced load, the excess waste nitrogen flows sequentially through the third low-temperature heat exchanger fluid heat exchange channel of the low-temperature heat exchanger and the fourth high-temperature heat exchanger fluid heat exchange channel of the high-temperature heat exchanger for staged recovery of excess cold energy, and is stored in two propane storage tanks and two ethanol storage tanks respectively. The excess nitrogen from the cascade recovery of surplus cooling capacity is returned to the precooling system.

8. The energy release method according to claim 7, characterized in that, The temperature of the low-pressure air is the same as the original temperature of the low-pressure air in the internal compression air separation system; the temperature of the liquid air is the same as the original temperature of the liquid air in the internal compression air separation system. The total volume of low-pressure air entering the distillation system remains unchanged from the original total volume of low-pressure air entering the distillation system from the internal compression air separation system. The total volume of liquid air entering the distillation system remains unchanged from the original total volume of liquid air entering the distillation system from the internal compression air separation system. The liquefaction rate of the liquid air entering the distillation system remains unchanged from the original liquefaction rate of the liquid air entering the distillation system from the internal compression air separation system.

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