A fully enclosed compressed gas liquefied energy storage and power generation system

Abstract

The present invention discloses a fully enclosed compressed gas liquefaction energy storage and power generation system, comprising a compression system, a first heat exchange unit, a high-pressure gas-liquid storage container, a second heat exchange unit, a heat exchange system, an expansion system, a low-temperature expansion system, and a low-pressure gas-liquid storage container. The present invention liquefies and stores circulating gas, significantly reducing the volume of the storage tank; employs a direct heat exchange method involving the coexistence of high-temperature gas and low-temperature gas-liquid, thereby avoiding secondary heat exchange efficiency losses and accelerating system response speed; utilizes a fully enclosed circulation system with no other material input and output systems, and employs a combination of direct heat exchange and a low-temperature expander, resulting in fewer heat exchange systems and a simpler device structure; no flammable gas is involved in the circulation, thereby avoiding pollution to the atmospheric environment; and the system is compact and convenient to transport; and subsystems can be added within the module in a modular manner based on usage requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of compressed gas energy storage, and in particular relates to a fully enclosed compressed gas liquefied energy storage and power generation system. Background Art

[0002] The world is vigorously developing green energy generation technologies, such as wind power, tidal power, hydropower, and solar power. However, these technologies all exhibit significant peak-valley effects, causing frequent fluctuations in power transmission frequency. To effectively mitigate peaks and valleys and ensure normal equipment operation, reliable energy storage devices are required to regulate these fluctuations.

[0003] Compressed air energy storage compresses ambient air into high-pressure air, converting excess electrical energy into stored internal energy. When the energy is released, the high-pressure air drives an expansion system to perform work. This method offers high energy density, environmental friendliness, and a smaller footprint compared to other methods. However, it still has drawbacks: the air tanks are still bulky, making them inconvenient to transport and use; the components are highly interconnected and cannot be separated for use; and the system still requires air circulation for internal and external exchange, placing high demands on the operating environment and air purity, making it more difficult to use. Summary of the Invention

[0004] Technical problems to be solved: In response to the above technical problems, the present invention provides a fully enclosed compressed gas liquefied energy storage and power generation system, which can effectively solve the shortcomings of the above-mentioned compressed air energy storage device, such as large size, single usage environment, poor portability, and inability to be deployed at different points.

[0005] Technical solution: A fully enclosed compressed gas liquefaction energy storage and power generation system, including a compression system, a first heat exchange unit, a high-pressure gas-liquid storage container, a second heat exchange unit, a heat exchange system, an expansion system, a low-temperature expansion system and a low-pressure gas-liquid storage container, the compression system including a motor and a compressor unit, the compressor unit being electrically connected to the motor; the first heat exchange unit including a first channel, a second channel, a third channel and a fourth channel arranged in parallel; the second heat exchange unit including a fifth channel and a sixth channel arranged in parallel; the heat exchange system including a low-temperature tank and a high-temperature tank; the expansion system including an expander and a first generator, the expander being electrically connected to the first generator; the low-temperature expansion system including a low-temperature expander and a second generator, the low-temperature expander being electrically connected to the second generator;

[0006] The outlet of the compressor unit is connected to the inlet of the first channel, the outlet of the first channel is connected to the inlet of the high-pressure gas-liquid storage container, the outlet of the high-pressure gas-liquid storage container is connected to the inlet of the fifth channel, the outlet of the fifth channel is connected to the inlet of the expander, the outlet of the expander is connected to the inlet of the low-temperature expander, the outlet of the low-temperature expander is connected to the inlet of the low-pressure gas-liquid storage container, the outlet of the low-pressure gas-liquid storage container is connected to the inlet of the third channel, the outlet of the third channel is connected to the inlet of the compressor unit, the outlet of the low-temperature tank is connected to the inlet of the second channel, the outlet of the second channel is connected to the inlet of the high-temperature tank, the first outlet of the high-temperature tank is connected to the inlet of the sixth channel, the outlet of the sixth channel is connected to the inlet of the low-temperature tank, the second outlet of the high-temperature tank is connected to the inlet of the fourth channel, and the outlet of the fourth channel is connected to the inlet of the low-temperature tank.

[0007] Preferably, a first valve is provided on the pipe connecting the outlet of the first channel and the inlet of the high-pressure gas-liquid storage container, a second valve is provided on the pipe connecting the outlet of the high-pressure gas-liquid storage container and the inlet of the fifth channel, a third valve is provided on the pipe connecting the outlet of the second channel and the inlet of the high-temperature tank, a fourth valve is provided on the pipe connecting the second outlet of the high-temperature tank and the inlet of the fourth channel, a fifth valve is provided on the pipe connecting the first outlet of the high-temperature tank and the inlet of the sixth channel, a sixth valve is provided on the pipe connecting the outlet of the low-temperature expander and the inlet of the low-pressure gas-liquid storage container, and a seventh valve is provided on the pipe connecting the outlet of the low-pressure gas-liquid storage container and the inlet of the third channel.

[0008] Preferably, the compressor unit is one or more of an axial flow compressor, a centrifugal compressor, a mixed flow compressor, a reciprocating compressor, a scroll compressor, and a screw compressor connected in series or in parallel.

[0009] Preferably, the expanders are one or more of an axial flow expander, a centripetal expander, a mixed flow expander, and a reciprocating expander connected in series or in parallel.

[0010] Preferably, the compressor unit is provided with an initial medium inlet.

[0011] Furthermore, the initial medium is one or a mixture of air, carbon dioxide, and helium.

[0012] Preferably, the heat exchange medium between the low-temperature tank and the high-temperature tank is water, air, paraffin, biomass oil, thermal oil, inorganic crystalline hydrated salt, molten salt, organic fatty acid, propane or ethylene glycol solution.

[0013] Beneficial effects: In terms of volume: the circulating gas is liquefied and stored, greatly reducing the volume of the storage tank;

[0014] Efficiency: Direct heat exchange between high-temperature gas and low-temperature gas-liquid coexistence is adopted to avoid secondary heat exchange efficiency loss and speed up system response;

[0015] Structurally: Fully enclosed circulation, no other material input and output systems, using direct heat exchange combined with a low-temperature expander, resulting in fewer heat exchange systems and a simple device structure;

[0016] Environmental protection: no flammable gas is involved in the cycle, thus avoiding pollution to the atmospheric environment;

[0017] Portability: small size, easy to transport;

[0018] In terms of specifications: subsystems can be added in the module in the form of building blocks according to usage requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of a fully enclosed compressed gas liquefied energy storage and power generation system of the present invention;

[0020] Figure 2 yes Figure 1 Schematic diagram of the structure of the initial stage of compressed gas energy storage;

[0021] Figure 3 yes Figure 1 Schematic diagram of the structure of the complete stage of medium-compressed gas energy storage;

[0022] Figure 4 yes Figure 1 Schematic diagram of the structure during the expansion gas energy release stage;

[0023] Sequence numbers in the figure: 1. Compression system, 11. Motor, 12. Compressor unit, 2. First heat exchange unit, 21. First channel, 22. Second channel, 23. Third channel, 24. Fourth channel, 31. First valve, 32. Second valve, 33. Third valve, 34. Fifth valve, 36. Sixth valve, 37. Seventh valve, 4. High-pressure gas-liquid storage container, 5. Heat exchange system, 51. Low-temperature tank, 52. High-temperature tank, 6. Second heat exchange unit, 61. Fifth channel, 62. Sixth channel, 7. Expansion system, 71. Expander, 72. First generator, 8. Low-temperature expansion system, 81. Low-temperature expander, 82. Second generator, 9. Low-pressure gas-liquid storage container. Implementation Method

[0024] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments: Example

[0025] like Figure 1As shown, a fully enclosed compressed gas liquefaction energy storage and power generation system includes a compression system 1, a first heat exchange unit 2, a high-pressure gas-liquid storage container 4, a second heat exchange unit 6, a heat exchange system 5, an expansion system 7, a low-temperature expansion system 8 and a low-pressure gas-liquid storage container 9, wherein the compression system 1 includes a motor 11 and a compressor unit 12, and the compressor unit 12 is electrically connected to the motor 11; the first heat exchange unit 2 includes a first channel 21, a second channel 22, a third channel 23 and a fourth channel 24 arranged in parallel; the second heat exchange unit 6 includes a fifth channel 61 and a sixth channel 62 arranged in parallel; the heat exchange system 5 includes a low-temperature tank 51 and a high-temperature tank 52; the expansion system 7 includes an expander 71 and a first generator 72, and the expander 71 is electrically connected to the first generator 72; the low-temperature expansion system 8 includes a low-temperature expander 81 and a second generator 82, and the low-temperature expander 81 is electrically connected to the second generator 82;

[0026] The outlet of the compressor unit 12 is connected to the inlet of the first channel 21, the outlet of the first channel 21 is connected to the inlet of the high-pressure gas-liquid storage container 4, the outlet of the high-pressure gas-liquid storage container 4 is connected to the inlet of the fifth channel 61, the outlet of the fifth channel 61 is connected to the inlet of the expander 71, the outlet of the expander 71 is connected to the inlet of the low-temperature expander 81, the outlet of the low-temperature expander 81 is connected to the inlet of the low-pressure gas-liquid storage container 9, the outlet of the low-pressure gas-liquid storage container 9 is connected to the inlet of the third channel 23, the outlet of the third channel 23 is connected to the inlet of the compressor unit 12, the outlet of the low-temperature tank 51 is connected to the inlet of the second channel 22, the outlet of the second channel 22 is connected to the inlet of the high-temperature tank 52, the first outlet of the high-temperature tank 52 is connected to the inlet of the sixth channel 62, the outlet of the sixth channel 62 is connected to the inlet of the low-temperature tank 51, the second outlet of the high-temperature tank 52 is connected to the inlet of the fourth channel 24, and the outlet of the fourth channel 24 is connected to the inlet of the low-temperature tank 51.

[0027] A first valve 31 is provided on the pipe connecting the outlet of the first channel 21 and the inlet of the high-pressure gas-liquid storage container 4, a second valve 32 is provided on the pipe connecting the outlet of the high-pressure gas-liquid storage container 4 and the inlet of the fifth channel 61, a third valve 33 is provided on the pipe connecting the outlet of the second channel 22 and the inlet of the high-temperature tank 52, a fourth valve 34 is provided on the pipe connecting the second outlet of the high-temperature tank 52 and the inlet of the fourth channel 24, a fifth valve 35 is provided on the pipe connecting the first outlet of the high-temperature tank 52 and the inlet of the sixth channel 62, a sixth valve 36 is provided on the pipe connecting the outlet of the low-temperature expander 81 and the inlet of the low-pressure gas-liquid storage container 9, and a seventh valve 37 is provided on the pipe connecting the outlet of the low-pressure gas-liquid storage container 9 and the inlet of the third channel 23.

[0028] The compressor unit 12 is one or more of an axial flow compressor, a centrifugal compressor, a mixed flow compressor, a reciprocating compressor, a scroll compressor, and a screw compressor, which are connected in series or in parallel.

[0029] The expander 71 is one or more of an axial flow expander, a centripetal expander, a mixed flow expander, and a reciprocating expander connected in series or in parallel.

[0030] The compressor unit 12 is provided with an initial medium inlet.

[0031] The initial medium is one or a mixture of air, carbon dioxide, and helium.

[0032] The heat exchange medium between the low temperature tank 51 and the high temperature tank 52 is water, air, paraffin, biomass oil, thermal oil, inorganic crystalline hydrated salt, molten salt, organic fatty acid, propane or ethylene glycol solution.

[0033] The working principle of the system of the present invention is as follows: the boiling point of gas increases with the increase of gas pressure. When it exceeds the boiling point, it is in gaseous state, and when it is below the boiling point, it is in liquid state. In the initial stage of compressed energy storage, the amount of gas in the low-pressure gas-liquid coexistence body that can enter the compression system to perform work is relatively small, resulting in less heat released by the high-temperature and high-pressure gas, and the operating efficiency of the compressed energy storage system is low. In order to change this state and maximize the utilization of system efficiency, the system sets an initial stage of compressed energy storage and uses a heat exchange system to accelerate the heat absorption and vaporization of the low-pressure gas-liquid coexistence body so that the optimal operating stage of the compressed energy storage system is reached as soon as possible; when the heat released by the high-temperature and high-pressure gas meets the heat required for the vaporization of the low-pressure gas-liquid coexistence body, the heat released by the heat exchange system to the low-pressure coexistence body is closed, and the valve of the high-temperature tank is opened to store the excess heat after the high-temperature and high-pressure gas releases heat to the low-pressure gas-liquid coexistence body. This can avoid heat loss and low efficiency caused by the heat exchange system using the high-temperature and high-pressure gas and the low-pressure gas-liquid coexistence body as heat exchange media. In the expansion gas energy release link, the high-pressure gas-liquid coexistence body expands and vaporizes by absorbing the heat energy stored in the heat exchange system, and is transported to the expansion system to do work and release electrical energy. It is then further reduced in pressure and temperature by a low-temperature expander to liquefy for easy storage.

[0034] Initial stage of compressed gas energy storage: When the energy storage system is operating inefficiently and the high-temperature, high-pressure gas does not release enough heat, the heat exchange system is operated to release heat to the low-pressure gas-liquid coexistence to accelerate gasification, allowing the compressed energy storage system to achieve higher operating efficiency in a shorter period of time. The specific operation process is: open the first valve 31, the seventh valve 37, and the fourth valve 34, and keep the third valve 33, the sixth valve 36, the second valve 32, and the fifth valve 35 closed. The structural diagram is shown in the figure below. Figure 2As shown, the gas-liquid coexistence stored in the low-pressure gas-liquid storage container 9 is transported to the third channel 23 in the first heat exchange unit 2, absorbs heat, expands and vaporizes, and then enters the compressor unit 12 in the compression system 1. The motor 11 drives the compressor unit 12 to work and compress the gas. The high-temperature and high-pressure gas output from the compressor unit 12 enters the first channel 21 in the first heat exchange unit 2 to release heat and liquefy, and then is transported to the high-pressure gas-liquid storage container 4; the heat exchange medium in the high-temperature tank 52 flows out to the fourth channel 24 in the first heat exchange unit 2 through the fourth valve 34 to release heat, and the heat exchange medium after releasing heat is transported to the low-temperature tank 51.

[0035] Compressed gas energy storage complete stage: As the system further develops and enters the compressed gas energy storage complete stage, high-temperature and high-pressure gas and low-pressure gas-liquid coexistence are used to directly exchange heat, which can reduce the heat loss of the heat exchange medium in the heat exchange system, low efficiency, slow system response and other shortcomings. The heat exchange system is used to store the heat energy released by the liquefaction of high-temperature and high-pressure gas, and keep the first valve 31 and the seventh valve 37 open. Its structural diagram is shown as follows: Figure 3 As shown, the third valve 33 is gradually opened until it is fully opened, so that the heat exchange medium in the low-temperature tank 51 is transported to the second channel 22 in the first heat exchange unit 2 to absorb heat, and then transported to the high-temperature tank 52 for storage, and the fourth valve 34 is gradually closed until it is fully closed, thereby reducing the heat exchange system 5 from participating in the heat absorption and gasification process of the low-pressure gas-liquid coexistence body.

[0036] In the expansion gas energy release stage: close the first valve 31, the seventh valve 37 and the third valve 33, keep the fourth valve 34 closed, open the second valve 32, the sixth valve 36 and the fifth valve 35, the structural diagram of which is shown in FIG. Figure 4 As shown, the gas-liquid coexistence stored in the high-pressure gas-liquid storage container 4 is transported to the fifth channel 61 of the second heat exchange unit 6, where it absorbs heat, expands, and vaporizes to form high-temperature, high-pressure gas. The gas is then transported to the expander 71 in the expansion system 7 to produce work. The expander 71 drives the first generator 72 to output electrical energy. The gas output from the expansion system 7 enters the low-temperature expander 81 in the low-temperature expansion system 8 to expand again and produce work. The low-temperature expander 81 drives the second generator 82 to output electrical energy. After cooling and reducing the pressure in the low-temperature expander 81, the gas is liquefied and transported to the low-pressure gas-liquid storage container 9. The heat exchange medium in the high-temperature tank 52 is transported through the fifth valve 35 to the sixth channel 62 of the second heat exchange unit 6 to release heat, and then transported to the low-temperature tank 51 for storage.

[0037] The initial medium used in this system can be any gas that can be easily converted between gas and liquid. Preferred initial media are air, carbon dioxide, helium, or a mixture of these. For example, carbon dioxide has a saturation pressure of 0.422 MPa at -56.5°C and 7.376 MPa at 31°C, conservatively estimated to provide a compression ratio of more than 16 times.

[0038] The present invention provides a fully enclosed compressed gas liquefaction energy storage and power generation system. Except for electrical energy, no other energy sources and substances are involved in the internal and external exchange. The compressed gas energy storage stage is divided into two stages: in the first initial stage, when the system operation efficiency is low and the high-temperature and high-pressure gas releases insufficient heat, a heat exchange system is added to release heat to the low-pressure gas-liquid coexistence body to accelerate gasification, so that the compressed energy storage system can reach a higher operation efficiency in a shorter time; in the second complete stage, high-temperature and high-pressure gas is used to directly exchange heat with the low-pressure gas-liquid coexistence body to reduce the heat loss, low efficiency, slow system response and other shortcomings caused by the heat exchange system as a heat exchange medium, and the heat exchange system is used to store the heat energy released by the liquefaction of the high-temperature and high-pressure gas; the low-pressure gas is liquefied in the form of a low-temperature pump, and combined with segmented energy storage, the system only needs one heat exchange system. Compared with other compressed gas liquefaction energy storage systems, the number of heat exchange systems is reduced, which greatly reduces the system complexity and the difficulty of use and installation.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fully enclosed compressed gas liquefaction energy storage and power generation system, characterized by: It includes a compression system, a first heat exchange unit, a high-pressure gas-liquid storage container, a second heat exchange unit, a heat exchange system, an expansion system, a low-temperature expansion system and a low-pressure gas-liquid storage container. The compression system includes a motor and a compressor unit, wherein the compressor unit is electrically connected to the motor; The first heat exchange unit comprises a first channel, a second channel, a third channel and a fourth channel arranged in parallel; The second heat exchange unit includes a fifth channel and a sixth channel arranged in parallel; The heat exchange system includes a low-temperature tank and a high-temperature tank; The expansion system includes an expander and a first generator, wherein the expander is electrically connected to the first generator; The low-temperature expansion system includes a low-temperature expander and a second generator, wherein the low-temperature expander is electrically connected to the second generator; The outlet of the compressor unit is connected to the inlet of the first channel, the outlet of the first channel is connected to the inlet of the high-pressure gas-liquid storage container, the outlet of the high-pressure gas-liquid storage container is connected to the inlet of the fifth channel, the outlet of the fifth channel is connected to the inlet of the expander, the outlet of the expander is connected to the inlet of the low-temperature expander, the outlet of the low-temperature expander is connected to the inlet of the low-pressure gas-liquid storage container, the outlet of the low-pressure gas-liquid storage container is connected to the inlet of the third channel, the outlet of the third channel is connected to the inlet of the compressor unit, the outlet of the low-temperature tank is connected to the inlet of the second channel, the outlet of the second channel is connected to the inlet of the high-temperature tank, the first outlet of the high-temperature tank is connected to the inlet of the sixth channel, the outlet of the sixth channel is connected to the inlet of the low-temperature tank, the second outlet of the high-temperature tank is connected to the inlet of the fourth channel, and the outlet of the fourth channel is connected to the inlet of the low-temperature tank.

2. A fully enclosed compressed gas liquefaction energy storage and power generation system according to claim 1, characterized in that: A first valve is provided on the pipe connecting the outlet of the first channel and the inlet of the high-pressure gas-liquid storage container, a second valve is provided on the pipe connecting the outlet of the high-pressure gas-liquid storage container and the inlet of the fifth channel, a third valve is provided on the pipe connecting the outlet of the second channel and the inlet of the high-temperature tank, a fourth valve is provided on the pipe connecting the second outlet of the high-temperature tank and the inlet of the fourth channel, a fifth valve is provided on the pipe connecting the first outlet of the high-temperature tank and the inlet of the sixth channel, a sixth valve is provided on the pipe connecting the outlet of the low-temperature expander and the inlet of the low-pressure gas-liquid storage container, and a seventh valve is provided on the pipe connecting the outlet of the low-pressure gas-liquid storage container and the inlet of the third channel.

3. The fully enclosed compressed gas liquefied energy storage and power generation system according to claim 1, characterized in that: The compressor unit is one or more of an axial flow compressor, a centrifugal compressor, a mixed flow compressor, a reciprocating compressor, a scroll compressor, and a screw compressor connected in series or in parallel.

4. A fully enclosed compressed gas liquefaction energy storage and power generation system according to claim 1, characterized in that: The expander is one or more of an axial flow expander, a centripetal expander, a mixed flow expander, and a reciprocating expander connected in series or in parallel.

5. The fully enclosed compressed gas liquefaction energy storage and power generation system according to claim 1, characterized in that: The compressor unit is provided with an initial medium inlet.

6. A fully enclosed compressed gas liquefied energy storage and power generation system according to claim 5, characterized in that: The initial medium is one or a mixture of air, carbon dioxide, and helium.

7. The fully enclosed compressed gas liquefaction energy storage and power generation system according to claim 1, characterized in that: The heat exchange medium between the low temperature tank and the high temperature tank is water, air, paraffin, biomass oil, thermal oil, inorganic crystalline hydrated salt, molten salt, organic fatty acid, propane or ethylene glycol solution.

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