Hydraulic compression energy storage nitrogen production system based on phase change working medium and operation method

Abstract

The application discloses a kind of nitrogen production systems of hydraulic compression energy storage based on phase change working medium, including nitrogen production reaction separator, air bag, water supply equipment, reservoir and heat exchanger;Nitrogen production reaction separator is provided with air inlet, water inlet, vent, nitrogen outlet and liquid oxygen outlet;Air inlet is used to supply air into nitrogen production reaction separator inside, air bag is arranged in nitrogen production reaction separator inside, and water supply equipment supplies water to air bag;Reservoir includes liquid nitrogen reservoir and liquid oxygen reservoir, nitrogen discharged from nitrogen outlet is cooled into liquid nitrogen and stored in liquid nitrogen reservoir, and liquid oxygen reservoir is communicated with the liquid oxygen outlet;Liquid nitrogen reservoir and liquid oxygen reservoir are respectively used to supply liquid nitrogen and liquid oxygen heat exchange medium into heat exchanger;Air bag is used to control the pressure inside nitrogen production reaction separator.Utilize self-produced liquid oxygen and part liquid nitrogen product as cold source, realize the internal circulation of product cold quantity.Maximally reduce external cooling demand, improve system energy utilization efficiency.

Description

Technical Field

[0001] This invention belongs to the field of cryogenic air separation nitrogen production technology, specifically relating to a hydraulic compression energy storage nitrogen production system based on phase change working fluid and its operation method. Background Technology

[0002] The demand for nitrogen in the industrial sector is growing, and it plays an irreplaceable role in industries such as chemical, metallurgical, electronics and food.

[0003] Cryogenic air separation, as a mainstream technology for large-scale nitrogen production, is mature and reliable. However, its core reliance on high-speed rotating multi-stage compressors and turbine expanders leads to complex system structures, high manufacturing and maintenance costs, and huge energy consumption. This process suffers from slow start-up, poor operational flexibility, difficulty adapting to load fluctuations, and poor economic efficiency in small- to medium-scale applications. Another prominent problem with existing cryogenic air separation units is their low system integration; the compression, precooling, purification, liquefaction, and distillation modules are relatively independent, making the entire system large and cumbersome.

[0004] Although pressure sieving (PSA) and membrane separation methods have relatively simple equipment, they can usually only produce gaseous nitrogen with low purity, which is difficult to meet the market demand for high-purity liquid nitrogen products, and their operating energy consumption is still not negligible.

[0005] Therefore, providing a nitrogen generation system with high integration, simplified equipment, and low energy consumption is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The technical problem this invention aims to solve is to address the shortcomings of the prior art by providing a hydraulic compression energy storage nitrogen generation system and its operation method based on phase change working fluid. This system utilizes self-produced liquid oxygen and a portion of liquid nitrogen as a cold source, achieving internal circulation of the product's cooling capacity. This minimizes the need for external cooling and improves the system's energy utilization efficiency, thus solving the technical problems of low integration, complex equipment, and high energy consumption in existing nitrogen generation systems.

[0007] This invention adopts the following technical solution: a hydrodynamic compression energy storage nitrogen generation system based on phase change working fluid, comprising a nitrogen generation reaction separator, an air bladder, a water supply device, a storage tank, and a heat exchanger; the nitrogen generation reaction separator is provided with an air inlet, a water inlet, an vent, a nitrogen outlet, and a liquid oxygen outlet; the air inlet is used to supply air into the nitrogen generation reaction separator, the air bladder is disposed inside the nitrogen generation reaction separator, and the water supply device supplies water to the air bladder through the water inlet; The storage device includes a liquid nitrogen storage device and a liquid oxygen storage device. The nitrogen gas discharged from the nitrogen outlet is cooled into liquid nitrogen and stored in the liquid nitrogen storage device. The liquid oxygen storage device is connected to the liquid oxygen outlet. The liquid nitrogen and liquid oxygen storage tanks are used to supply liquid nitrogen and liquid oxygen heat exchange media to the heat exchanger and to cool the air inside the nitrogen generation reaction separator, respectively. The airbag is used to control the internal pressure of the nitrogen generation reaction separator.

[0008] Preferably, the nitrogen storage device is arranged inside the liquid oxygen storage device, and the nitrogen gas exiting the nitrogen outlet passes through the liquid oxygen storage device, is cooled into liquid nitrogen by the liquid oxygen storage device, and is stored in the liquid nitrogen storage device.

[0009] Preferably, the medium outlet of the heat exchanger is connected to the atmosphere.

[0010] Preferably, a throttling valve is provided between the liquid oxygen outlet and the liquid oxygen storage tank.

[0011] Preferably, the water supply device includes a water tank and a water pump, wherein the water pump supplies water from the water tank into the airbag.

[0012] Preferably, an air filter is connected to the air inlet.

[0013] Preferably, the nitrogen outlet is equipped with a molecular sieve adsorber, which is used to sieve the gas at the nitrogen outlet to obtain nitrogen.

[0014] Preferably, the heat exchanger is a jacketed heat exchanger installed on the outer periphery of the nitrogen production reaction separator.

[0015] Another technical solution of the present invention is an operation method for a hydraulic compression energy storage nitrogen production system based on phase change working fluid, comprising the following steps: Water is supplied to the airbag using a water supply device, which compresses the air inside the nitrogen generator separator into high-temperature and high-pressure air. The air inside the nitrogen generator is cooled by a heat exchanger. The high-temperature and high-pressure air is cooled to high-pressure and low-temperature air. The airbag is controlled to contract and the air is controlled to expand so that the air temperature is between the boiling points of oxygen and nitrogen. Liquid oxygen is collected at the bottom of the nitrogen generator and gaseous nitrogen is discharged from the nitrogen outlet at the top. Liquid oxygen is stored in a liquid oxygen storage tank after passing through the liquid oxygen outlet, and nitrogen is cooled into liquid nitrogen and then stored in a liquid nitrogen storage tank to obtain liquid nitrogen product; The liquid oxygen and liquid nitrogen storage tanks are connected to the heat exchanger to supply the heat exchanger with the heat exchange medium.

[0016] Preferably, the liquid oxygen from the liquid oxygen outlet enters the liquid oxygen storage tank after being de-cooled and de-pressurized by a throttle valve.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: This invention integrates key processes such as hydraulic compression, heat exchanger heat exchange, distillation separation, and product liquefaction into a core device—a nitrogen-generating reaction separator—replacing the independent multi-stage compressors, turbine expanders, and bulky tower systems found in traditional cryogenic air separation systems. This integrated design eliminates reliance on high-speed rotating machinery, resulting in a more compact and simpler equipment structure. This significantly reduces manufacturing and maintenance costs while improving system reliability and lifespan, making it particularly suitable for distributed, modular applications.

[0018] By creatively utilizing self-produced liquid oxygen and a portion of liquid nitrogen as a cooling source, an internal circulation of product cooling capacity has been achieved. This integrated energy and cooling management strategy minimizes external cooling demand, resulting in high system energy utilization efficiency and effectively reducing the overall energy consumption per unit of liquid nitrogen product.

[0019] Furthermore, by placing a liquid nitrogen storage device inside a liquid oxygen storage device and using the prepared liquid oxygen to cool the liquid nitrogen, the internal cooling capacity can be recycled, and liquid nitrogen products can be obtained without the need for additional cooling equipment.

[0020] Furthermore, the top nitrogen gas undergoes final purification via a molecular sieve adsorber, ensuring the high purity of the liquid nitrogen product.

[0021] In summary, this invention deeply integrates hydraulic compression, phase change separation, and a product cooling internal circulation mechanism to construct an unconventional, compact air separation system based on hydrostatic expansion refrigeration. It abandons traditional high-speed rotating machinery, achieving a closed-loop process of air compression, cooling, phase change separation, and energy recovery within a single reactor through hydraulic drive and precise temperature control expansion. Using self-produced liquid oxygen and liquid nitrogen as the core cooling source, a direct heat exchange network is established between the product and the feedstock air, achieving efficient self-sufficiency and recycling of cooling capacity.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the following description of the relative embodiments will be briefly introduced. Obviously, the 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.

[0024] Figure 1 This is a flowchart of a hydraulic compression energy storage nitrogen generation system based on phase change working fluid according to the present invention.

[0025] The components include: 1. Nitrogen generation reaction separator; 2. Gas bag; 3. Electric motor; 4. Water pump; 5. Water tank; 6. Throttling valve; 7. Liquid oxygen storage tank; 8. Liquid nitrogen storage tank; 9. Air filter; 10. Molecular sieve adsorber. Detailed Implementation

[0026] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "one side," "one end," and "one side," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0030] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0031] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0032] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0033] This invention provides a hydrodynamic compression energy storage nitrogen generation system based on phase change working fluid. By deeply integrating hydrodynamic compression, phase change separation and product cooling internal circulation mechanism, a non-traditional compact air separation system based on static pressure expansion refrigeration is constructed.

[0034] Abandoning traditional high-speed rotating machinery, this system achieves a closed-loop process of air compression, cooling, phase change separation, and energy recovery within a single reactor through hydraulic drive and precise temperature control expansion. Using self-produced liquid oxygen and liquid nitrogen as the core cold source, a direct heat exchange network is established between the products and the raw air, enabling efficient self-sufficiency and recycling of cooling capacity.

[0035] Please see Figure 1 As shown, the present invention discloses a hydrodynamic compression energy storage nitrogen generation system based on phase change working fluid, comprising a nitrogen generation reaction separator 1, a gas bladder 2, a water supply device, a storage device, and a heat exchanger.

[0036] Among them, such as Figure 1 As shown, the nitrogen generator separator 1 is equipped with an air inlet, a water inlet, a vent, a nitrogen outlet, and a liquid oxygen outlet. The air inlet is used to supply air into the nitrogen generator separator 1, and the air bladder 2 is installed inside the nitrogen generator separator 1. The water supply equipment supplies water to the air bladder 2 through the water inlet.

[0037] The storage device includes a liquid nitrogen storage device 8 and a liquid oxygen storage device 7. The nitrogen gas discharged from the nitrogen outlet is cooled into liquid nitrogen and stored in the liquid nitrogen storage device 8. The liquid oxygen storage device 7 is connected to the liquid oxygen outlet and is used to store liquid oxygen.

[0038] The heat exchanger uses a combination of liquid nitrogen and liquid oxygen as a cooling medium to cool the air inside the nitrogen generation reaction separator 1, thereby producing liquid oxygen and nitrogen. In this embodiment, the liquid nitrogen storage tank 8 and the liquid oxygen storage tank 7 are used to supply liquid nitrogen and liquid oxygen heat exchange medium to the heat exchanger and to cool the air inside the nitrogen generation reaction separator 1, respectively.

[0039] During operation, water is supplied into the airbag 2 to control the internal pressure of the nitrogen-generating reaction separator 1, and the nitrogen and liquid oxygen are generated in conjunction with the cooling of the heat exchanger.

[0040] This invention integrates key processes such as hydraulic compression, heat exchanger heat exchange, distillation separation, and product liquefaction into a core device called nitrogen production reaction separator 1, replacing the independent multi-stage compressors, turbine expanders, and bulky tower systems found in traditional cryogenic air separation systems. This integrated design eliminates reliance on high-speed rotating machinery, resulting in a more compact and simpler equipment structure. This significantly reduces manufacturing and maintenance costs while improving system reliability and lifespan, making it particularly suitable for distributed and modular applications.

[0041] By creatively utilizing self-produced liquid oxygen and a portion of liquid nitrogen as a cooling source, an internal circulation of product cooling capacity has been achieved. This integrated energy and cooling management strategy minimizes external cooling demand, resulting in high system energy utilization efficiency and effectively reducing the overall energy consumption per unit of liquid nitrogen product.

[0042] 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0043] Please see Figure 1 As shown, in the hydrodynamic compression energy storage nitrogen production system based on phase change working fluid of the present invention, the storage device has a double-layer structure from the inside to the outside, wherein the inner layer is a liquid nitrogen storage device 8 and the outer layer is a liquid oxygen storage device 7. The outer liquid oxygen storage device constitutes a gas storage heat exchange part.

[0044] Specifically, the nitrogen gas exiting the nitrogen outlet passes through the outer liquid oxygen storage tank 7 and reaches the liquid nitrogen storage tank 8. During this process, the nitrogen gas is cooled into liquid nitrogen by the liquid oxygen storage tank 7 and stored in the liquid nitrogen storage tank 8, thus producing liquid nitrogen products.

[0045] A liquid nitrogen storage tank 8 is placed inside a liquid oxygen storage tank 7. The liquid oxygen produced is used to cool the liquid nitrogen, achieving internal cooling energy recycling. Liquid nitrogen products can be obtained without the need for additional cooling equipment. At the same time, part of the produced liquid nitrogen product is fed into a heat exchanger as a heat exchange medium and reintegrated into the system for circulation, achieving cold source backup.

[0046] Specifically, a nitrogen delivery pipeline can be installed inside the liquid oxygen storage tank 7. The inlet of the nitrogen delivery pipeline is connected to the nitrogen outlet, and the outlet of the nitrogen delivery pipeline is connected to the liquid nitrogen storage tank 8. After the nitrogen is injected into the nitrogen delivery pipeline, it is gradually cooled into liquid nitrogen and stored in the liquid nitrogen storage tank 8 as it passes through the liquid oxygen storage tank 7. At the same time, the liquid nitrogen storage tank 8 is arranged inside the liquid oxygen storage tank 7, so that the liquid oxygen storage tank 7 can be used as the storage container for the liquid nitrogen storage tank 8, which facilitates the preservation of liquid nitrogen.

[0047] In other embodiments, when meeting actual usage requirements, the liquid nitrogen storage 8 may not be arranged inside the liquid oxygen storage 7. In this case, the liquid nitrogen storage 8 may be arranged on one side of the liquid oxygen storage 7. Specifically, a cooling pipe is provided on the liquid oxygen storage 7 to penetrate its interior. One end of the cooling pipe is connected to the nitrogen outlet and the other end is connected to the liquid nitrogen storage 8. After the liquid nitrogen comes out through the nitrogen outlet, it is cooled into liquid nitrogen by the liquid oxygen and stored in the liquid nitrogen storage 8 during the process of passing through the cooling pipe.

[0048] In other embodiments, when meeting actual usage requirements, other methods can be used to cool the prepared nitrogen gas to obtain liquid nitrogen, such as setting an external refrigeration unit at the nitrogen outlet and directly cooling the prepared nitrogen gas to produce liquid nitrogen through the external refrigeration unit.

[0049] Preferably, in this embodiment, the heat exchanger is a jacketed heat exchanger disposed around the periphery of the nitrogen generation reaction separator 1. Uniform cooling and heat exchange are achieved using the jacketed heat exchanger. The media outlets of the liquid nitrogen storage tank 8 and the liquid oxygen storage tank 7 converge into a branch and connect to the media inlet of the jacketed heat exchanger. The media outlet of the jacketed heat exchanger is connected to the atmosphere, and the nitrogen and oxygen obtained after heat exchange are discharged into the air.

[0050] In other embodiments, when meeting actual usage requirements, the heat exchanger may also adopt existing structures suitable for tank heat exchange, such as shell-and-tube heat exchangers, coil heat exchangers, plate heat exchangers, or shell-and-tube heat exchangers.

[0051] In this embodiment, as Figure 1As shown, a throttle valve 6 is installed on the pipeline connecting the liquid oxygen outlet and the liquid oxygen storage tank 7. After the liquid oxygen is de-cooled and depressurized by the throttle valve 6, it flows steadily into the liquid oxygen storage tank 7 at a stable pressure and temperature, thus achieving safe storage of liquid oxygen.

[0052] In this embodiment, the air inlet of the nitrogen generation reaction separator 1 is located at the upper end of the nitrogen generation reaction separator 1, and an air filter 9 is connected to the air inlet. The air is filtered by the air filter 9 and then injected into the nitrogen generation reaction separator 1.

[0053] Preferably, in this embodiment, the water supply equipment includes a water tank 5 and a water pump 4. The water inlet of the water pump 4 is connected to the water tank 5, and the water outlet is connected to the air bladder 2. When the water pump 4 is working, it pressurizes the water in the water tank 5 and delivers it to the inside of the air bladder 2 to realize the water filling operation of the air bladder 2.

[0054] Specifically, in this embodiment, an electric motor 3 is provided on the water pump 4. The electric motor 3 is used to provide power to the water pump when filling with water, so as to inject water into the air bag 2.

[0055] During system operation, when liquid oxygen and liquid nitrogen are mixed and sent to the heat exchanger to cool the high-temperature and high-pressure air of nitrogen generator 1, the high-temperature and high-pressure air of nitrogen generator 1 is cooled to high-pressure and low-temperature air. Then the high-pressure air expands, which in turn drives the air bag 2 to contract, and in turn drives the water pump 4 to do work, thereby improving the overall energy utilization rate of the system.

[0056] Specifically, the combination of water pump 4 and motor 3 can be a bidirectional axial flow pump. The bidirectional axial flow pump can operate in both directions. When it runs in the forward direction, it is in water pump mode, and when it rotates in the reverse direction, it is in power generation mode.

[0057] In other embodiments, a separate outlet can be provided on the airbag 2 to cooperate with the impeller and generator for energy recovery. Specifically, the outlet is connected to the water tank through a drain pipe, and an impeller and generator are installed on the drain pipe. When the airbag 2 drains water, the outlet opens, the water flow drives the impeller to rotate and drives the generator to generate electricity.

[0058] In this embodiment, as Figure 1 As shown, a molecular sieve adsorber 10 is installed at the nitrogen outlet. After gaseous nitrogen passes through the molecular sieve adsorber 10 to remove carbon dioxide and other impurities, it is stored in a liquid nitrogen storage heat exchanger. This ensures the purity and quality of the subsequent liquid nitrogen product, while preventing impurities from condensing in the low-temperature environment of subsequent cooling, which could lead to blockage of corresponding pipelines, damage to the heat exchanger or storage equipment, etc., thus ensuring the operational stability of the system.

[0059] The present invention provides an operation method for a hydraulic compression energy storage nitrogen production system based on a phase change working fluid, comprising the following steps: First, air is injected into the nitrogen generator separator 1 through the air inlet. Then, the motor 3 is started, and the water in the water tank 5 is sent to the air bladder 2 of the nitrogen generator separator 1 through the water pump 4. Water is supplied to the air bladder 2 through the water supply equipment, and the air inside the nitrogen generator separator 1 is compressed into high temperature and high pressure air.

[0060] Liquid oxygen from liquid oxygen storage 7 and a portion of liquid nitrogen from liquid nitrogen storage 8 are mixed to obtain a heat exchange medium, which is then sent to a jacketed heat exchanger to cool the high-temperature, high-pressure air inside the nitrogen generation reaction separator 1.

[0061] The high-temperature, high-pressure air in the nitrogen generator separator 1 is cooled to high-pressure, low-temperature air. Then, the high-pressure air expands, driving the water pump 4 to do work. At the same time, the air temperature in the nitrogen generator separator 1 begins to decrease. The air bladder 2 controls the degree of air expansion, keeping the air temperature between the boiling points of oxygen and nitrogen, so as to produce liquid oxygen. Nitrogen remains in gaseous form. At this time, the liquid oxygen accumulates at the bottom of the nitrogen generator separator 1, and the gaseous nitrogen accumulates at the top of the nitrogen generator separator 1.

[0062] Liquid oxygen at the bottom of nitrogen generator separator 1 is depressurized by throttle valve 6 and then enters liquid oxygen storage tank 7. Gaseous nitrogen at the top of nitrogen generator separator 1 passes through molecular sieve adsorber 10 to remove carbon dioxide and other impurities, and then enters liquid nitrogen storage heat exchanger after passing through the outer liquid oxygen storage tank 7. Since the temperature of liquid oxygen is lower than the boiling point of nitrogen, the nitrogen is cooled into liquid nitrogen as it passes through liquid oxygen storage tank 7, thus obtaining liquid nitrogen product, which is stored in liquid nitrogen storage tank 8.

[0063] The prepared liquid oxygen and liquid nitrogen are circulated and participate in the system operation. Specifically, the liquid oxygen in the liquid oxygen storage 7 enters the heat exchanger of the nitrogen generation reaction separator 1, and part of the liquid nitrogen in the liquid nitrogen storage 8 also enters the heat exchanger of the nitrogen generation reaction separator 1. After the two are mixed, they participate in heat exchange as a cooling medium, and after heat exchange in the outer jacket heat exchanger of the nitrogen generation reaction separator 1, they are discharged into the air.

[0064] In summary, the hydraulic compression energy storage nitrogen production system based on phase change working fluid of this invention deeply integrates hydraulic compression, phase change separation, and product cooling internal circulation mechanism to construct an unconventional, compact air separation system based on hydrostatic expansion refrigeration. It abandons traditional high-speed rotating machinery and achieves a closed-loop process of air compression, cooling, phase change separation, and energy recovery within a single reactor through hydraulic drive and precise temperature control expansion. Using self-produced liquid oxygen and liquid nitrogen as the core cold source of the system, a direct heat exchange network is established between the product and the raw air, realizing efficient self-sufficiency and recycling of cooling capacity.

[0065] Simultaneously, a technical approach combining hydraulic compression with precise temperature-controlled expansion is employed. By controlling the expansion process to keep the temperature directly between the boiling points of oxygen and nitrogen, gas-liquid two-phase separation is efficiently achieved within a single container, eliminating the need for the traditional complex dual-tower distillation structure. The top nitrogen gas undergoes final purification via a molecular sieve adsorber 10, ensuring the high purity of the liquid nitrogen product. This process is highly adaptable to load changes, and its start-up and adjustment are more rapid and flexible compared to traditional processes, enabling stable, efficient, and high-purity liquid nitrogen production from small to medium scales.

[0066] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A hydraulic compression energy storage nitrogen production system based on phase change working fluid, characterized in that, It includes a nitrogen-generating reaction separator (1), an air bag (2), a water supply device, a storage tank, and a heat exchanger; the nitrogen-generating reaction separator (1) is provided with an air inlet, a water inlet, an vent, a nitrogen outlet, and a liquid oxygen outlet; the air inlet is used to supply air into the nitrogen-generating reaction separator (1), the air bag (2) is located inside the nitrogen-generating reaction separator (1), and the water supply device supplies water to the air bag (2) through the water inlet; The storage device includes a liquid nitrogen storage device (8) and a liquid oxygen storage device (7). The nitrogen gas discharged from the nitrogen outlet is cooled into liquid nitrogen and stored in the liquid nitrogen storage device (8). The liquid oxygen storage device (7) is connected to the liquid oxygen outlet. The liquid nitrogen storage tank (8) and liquid oxygen storage tank (7) are used to supply liquid nitrogen and liquid oxygen heat exchange medium to the heat exchanger and to cool the air inside the nitrogen generation reaction separator (1), respectively. The airbag (2) is used to control the internal pressure of the nitrogen generation reaction separator (1).

2. The hydraulic compression energy storage nitrogen production system based on phase change working fluid according to claim 1, characterized in that, The nitrogen storage unit is arranged inside the liquid oxygen storage unit (7). The nitrogen gas coming out of the nitrogen outlet passes through the liquid oxygen storage unit (7), is cooled into liquid nitrogen by the liquid oxygen storage unit (7), and is stored in the liquid nitrogen storage unit (8).

3. The hydraulic compression energy storage nitrogen production system based on phase change working fluid according to claim 2, characterized in that, The medium outlet of the heat exchanger is connected to the atmosphere.

4. The hydraulic compression energy storage nitrogen production system based on phase change working fluid according to claim 1, characterized in that, A throttle valve (6) is provided between the liquid oxygen outlet and the liquid oxygen storage tank (7).

5. The hydraulic compression energy storage nitrogen production system based on phase change working fluid according to claim 1, characterized in that, The water supply equipment includes a water tank (5) and a water pump (4), the water pump (4) supplying water from the water tank (5) into the air bag (2).

6. The hydraulic compression energy storage nitrogen production system based on phase change working fluid according to claim 1, characterized in that, An air filter (9) is connected to the air inlet.

7. The hydraulic compression energy storage nitrogen production system based on phase change working fluid according to claim 1, characterized in that, The nitrogen outlet is equipped with a molecular sieve adsorber (10), which is used to sieve the gas at the nitrogen outlet to obtain nitrogen.

8. The hydraulic compression energy storage nitrogen production system based on phase change working fluid according to claim 1, characterized in that, The heat exchanger is a jacketed heat exchanger installed on the outer periphery of the nitrogen production reaction separator (1).

9. A method for operating a hydraulic compression energy storage nitrogen production system based on a phase change working fluid according to any one of claims 1-8, characterized in that, Includes the following steps: Water is supplied to the airbag (2) using a water supply device, and the air inside the nitrogen generator (1) is compressed into high temperature and high pressure air; The air inside the nitrogen generator (1) is cooled by a heat exchanger. The high-temperature and high-pressure air is cooled to high-pressure and low-temperature air. The air bag (2) is controlled to contract, and the air is controlled to expand so that the air temperature is between the boiling points of oxygen and nitrogen. Liquid oxygen is collected at the bottom of the nitrogen generator (1), and gaseous nitrogen is discharged from the nitrogen outlet at the top. Liquid oxygen is stored in liquid oxygen storage tank (7) after passing through the liquid oxygen outlet, and nitrogen is cooled into liquid nitrogen and stored in liquid nitrogen storage tank (8) to obtain liquid nitrogen product; The liquid oxygen storage tank (7) and the liquid nitrogen storage tank (8) are connected to the heat exchanger respectively, supplying the heat exchanger with heat exchange medium.

10. The operation method of the hydraulic compression energy storage nitrogen production system based on phase change working fluid according to claim 9, characterized in that, The liquid oxygen from the liquid oxygen outlet passes through the throttle valve (6) to reduce temperature and pressure before entering the liquid oxygen storage tank (7).

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