High-temperature energy storage and release system and method

Abstract

The invention provides a high-temperature energy storage and release system and method. The high-temperature energy storage and release system comprises a carbon dioxide system and an ammonia liquid system, and the carbon dioxide system comprises a low-temperature liquid carbon dioxide storage tank, a first air evaporator, a compressor, a heat accumulator, a water cooler, a high-pressure liquid carbon dioxide storage tank, a second air evaporator, a first expansion machine and a cold accumulator which are sequentially arranged. The ammonia liquid system comprises a third air evaporator and a second expansion machine, the inlet end and the outlet end of the third air evaporator are connected with the regenerator and the heat accumulator respectively, and the inlet end and the outlet end of the second expansion machine are connected with the heat accumulator and the regenerator respectively. The high-temperature energy storage and release system is simple in structure and high in energy utilization rate, storage of high-temperature heat energy and low-temperature cold energy is achieved, and large-scale long-time storage of energy is facilitated.

Description

Technical Field

[0001] The present invention relates to the field of energy storage and release technology, and in particular to a high-temperature energy storage and release system and method. Background Art

[0002] Energy storage is the process of storing energy through a medium or device and releasing it when needed. Under the "dual carbon" goal, renewable energy generation, including solar and wind power, has grown steadily; however, existing technologies are difficult to support the absorption of renewable energy that is increasing year by year, so large-scale energy storage devices are urgently needed to ensure the stable operation of the power grid.

[0003] At present, energy storage technologies at home and abroad mainly include pumped storage, compressed air storage, flywheel storage, chemical storage and superconducting storage, among which pumped storage and compressed air storage are widely used. However, the disadvantage of pumped storage system is that it is extremely dependent on terrain conditions, and the initial investment cost of construction is relatively high; compressed air storage has the advantages of large capacity, low cost, long working cycle, high safety factor, high efficiency and good economic performance, but large-scale compressed air storage system also has the problems of requiring a large number of gas storage caves and high requirements for geographical conditions. Therefore, a storage technology with long energy storage time and low requirements for geographical conditions is needed.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a high-temperature energy storage and release system and method, which realizes the storage of high-temperature thermal energy and low-temperature cold energy, and facilitates large-scale and long-term storage of energy.

[0006] The present invention provides a high-temperature energy storage and release system, comprising a carbon dioxide system and an ammonia liquid system. The carbon dioxide system comprises a low-temperature liquid carbon dioxide storage tank, a first air evaporator, a compressor, a heat accumulator, a water cooler, a high-pressure liquid carbon dioxide storage tank, a second air evaporator, a first expander and a cold accumulator, which are arranged in sequence. The ammonia liquid system comprises a third air evaporator and a second expander, the inlet end and the outlet end of the third air evaporator are respectively connected to the cold accumulator and the heat accumulator, and the inlet end and the outlet end of the second expander are respectively connected to the heat accumulator and the cold accumulator.

[0007] Furthermore, a cryogenic pump is provided between the cryogenic liquid carbon dioxide storage tank and the first air evaporator.

[0008] Furthermore, a throttling and pressure reducing valve is provided between the high-pressure liquid carbon dioxide storage tank and the second air evaporator.

[0009] Furthermore, a booster pump is provided between the cold storage device and the third air evaporator.

[0010] The present invention also provides a high-temperature energy storage and release method, which uses the above-mentioned high-temperature energy storage and release system to store and release energy.

[0011] Specifically, energy storage includes: sending the low-temperature liquid carbon dioxide in the low-temperature liquid carbon dioxide storage tank to the first air evaporator for gasification to form room-temperature gaseous carbon dioxide, the room-temperature gaseous carbon dioxide is pressurized by a compressor to form high-temperature and high-pressure gaseous carbon dioxide, the high-temperature and high-pressure gaseous carbon dioxide is recovered by a heat accumulator and cooled and liquefied by a water cooler to form high-pressure liquid carbon dioxide, and the high-pressure liquid carbon dioxide is sent to the high-pressure liquid carbon dioxide storage tank for storage.

[0012] Furthermore, the temperature of the low-temperature liquid carbon dioxide is -70°C to -80°C; the temperature of the high-temperature and high-pressure gaseous carbon dioxide is 450-500°C and the pressure is 7.0-8.0MPa; the temperature of the high-pressure liquid carbon dioxide is 20-25°C.

[0013] The energy release includes carbon dioxide energy release, and the carbon dioxide energy release includes: throttling and reducing the pressure of high-pressure liquid carbon dioxide and sending it to the second air evaporator for gasification to form high-pressure gaseous carbon dioxide, sending the high-pressure gaseous carbon dioxide to the first expansion machine for energy release, and the low-temperature liquid carbon dioxide formed by the energy release is stored in the cold storage device to form low-temperature liquid carbon dioxide, and the low-temperature liquid carbon dioxide is sent to the low-temperature liquid carbon dioxide storage tank for storage.

[0014] Furthermore, the energy release includes the energy release of ammonia liquid, and the energy release of ammonia liquid includes: pressurizing the ammonia liquid in the cold storage device to form high-pressure ammonia liquid, sending the high-pressure ammonia liquid to the third air evaporator for vaporization to form high-pressure room-temperature ammonia gas, increasing the temperature of the high-pressure room-temperature ammonia gas through the heat storage device to form high-pressure and high-temperature ammonia gas, sending the high-pressure and high-temperature ammonia gas to the second expansion machine for energy release, and the low-pressure and low-temperature ammonia gas formed by the energy release enters the cold storage device for cooling and condensation to form ammonia liquid and then continues to be recycled.

[0015] Furthermore, the temperature of the high-pressure and high-temperature ammonia is 300-450° C., and the pressure is 2-10 MPa.

[0016] The implementation of the present invention has at least the following advantages:

[0017] 1) The present invention uses high-pressure and low-temperature technology to liquefy high-pressure and low-pressure carbon dioxide gases and store them in storage tanks, which greatly saves the system footprint and reduces the restrictions on geographical conditions.

[0018] 2) The present invention compresses carbon dioxide into high-temperature and high-pressure carbon dioxide, which is convenient for the storage of high-temperature thermal energy; when releasing energy, the high-pressure carbon dioxide expands to release cold energy and is stored in the cold storage device, thus realizing the storage of high-temperature thermal energy and low-temperature cold energy.

[0019] 3) The present invention uses ammonia liquid as a medium to circulate between high-temperature heat energy and low-temperature cold energy, thereby realizing external output of electrical energy, and has the advantages of small amount of medium and high efficiency.

[0020] 4) The system structure of the present invention is simple, the energy utilization rate is high, and it is convenient for large-scale and long-term storage of energy. The combination with photovoltaic, wind power and other new energy systems is conducive to suppressing the volatility of new energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic structural diagram of the high-temperature energy storage and release system of the present invention.

[0023] Description of reference numerals:

[0024] 1: Cryogenic liquid carbon dioxide storage tank; 2: Cryogenic pump; 3: First air evaporator; 4: Compressor; 5: Heat accumulator; 6: Water cooler; 7: High-pressure liquid carbon dioxide storage tank; 8: Throttling and pressure reducing valve; 9: Second air evaporator; 10: First expander; 11: Cold accumulator; 12: Booster pump; 13: Third air evaporator; 14: Second expander. DETAILED DESCRIPTION

[0025] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0026] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] Combination Figure 1 As shown, the high-temperature energy storage and release system of this embodiment includes a carbon dioxide system and an ammonia liquid system. The carbon dioxide system includes a low-temperature liquid carbon dioxide storage tank 1, a first air evaporator 3, a compressor 4, a heat accumulator 5, a water cooler 6, a high-pressure liquid carbon dioxide storage tank 7, a second air evaporator 9, a first expander 10 and a cold accumulator 11 arranged in sequence. The ammonia liquid system includes a third air evaporator 13 and a second expander 14. The inlet and outlet ends of the third air evaporator 13 are respectively connected to the cold accumulator 11 and the heat accumulator 5, and the inlet and outlet ends of the second expander 14 are respectively connected to the heat accumulator 5 and the cold accumulator 11.

[0030] The cryogenic liquid carbon dioxide storage tank 1 is mainly used to store cryogenic liquid carbon dioxide, and the temperature of the cryogenic liquid carbon dioxide is -70°C to -80°C.

[0031] The first air evaporator 3 is mainly used to gasify the cryogenic liquid carbon dioxide stored in the cryogenic liquid carbon dioxide storage tank 1 into room temperature gaseous carbon dioxide; a cryogenic pump 2 is provided between the cryogenic liquid carbon dioxide storage tank 1 and the first air evaporator 3, and the cryogenic liquid carbon dioxide stored in the cryogenic liquid carbon dioxide storage tank 1 is sent to the first air evaporator 3 through the cryogenic pump 2 for gasification.

[0032] The compressor 4 is mainly used to pressurize the room temperature carbon dioxide gasified by the first air evaporator 3. The room temperature carbon dioxide is pressurized by the compressor 4 to form high temperature and high pressure gaseous carbon dioxide. The temperature of the high temperature and high pressure gaseous carbon dioxide is 450-500°C and the pressure is 7.0-8.0MPa.

[0033] The heat accumulator 5 is mainly used to recover the high-temperature heat of the high-temperature and high-pressure gaseous carbon dioxide.

[0034] The water cooler 6 is mainly used to cool down the high-pressure gaseous carbon dioxide after heat recovery and liquefy it into high-pressure liquid carbon dioxide.

[0035] The high-pressure liquid carbon dioxide storage tank 7 is mainly used to store high-pressure liquid carbon dioxide. A throttling and pressure-reducing valve 8 is provided between the high-pressure liquid carbon dioxide storage tank 7 and the second air evaporator 9. The throttling and pressure-reducing valve 8 is mainly used to throttle and reduce the pressure of the high-pressure liquid carbon dioxide stored in the high-pressure liquid carbon dioxide storage tank 7.

[0036] The second air evaporator 9 is mainly used to gasify the throttled and depressurized liquid carbon dioxide into high-pressure gaseous carbon dioxide.

[0037] The first expander 10 is mainly used to utilize high-pressure gaseous carbon dioxide to expand and perform work, thereby releasing energy to the outside to generate electricity; after the high-pressure gaseous carbon dioxide expands and performs work, the pressure is reduced to become low-temperature liquid carbon dioxide.

[0038] The cold storage device 11 is mainly used to store cold liquid carbon dioxide, and the stored liquid carbon dioxide enters the low-temperature liquid carbon dioxide storage tank 1 for storage; the cold storage device 11 uses liquid ammonia as a medium, and a booster pump 12 is provided between the cold storage device 11 and the third air evaporator 13. The booster pump 12 is mainly used to pressurize the liquid ammonia to form high-pressure liquid ammonia.

[0039] The third air evaporator 13 is mainly used to gasify high-pressure ammonia liquid into high-pressure room-temperature ammonia gas. The high-pressure room-temperature ammonia gas enters the heat accumulator 5 and is heated to about 300-450°C, and then enters the second expander 14 to expand and work, releasing energy to the outside to generate electricity. After the expansion and work, the ammonia gas becomes low-pressure and low-temperature ammonia gas and enters the cold accumulator 11 to cool and condense into ammonia liquid, and then enters the booster pump 12 to complete the cycle.

[0040] The high-temperature energy storage and release system of this embodiment compresses carbon dioxide through the compressor 4 to obtain high-temperature thermal energy, and the heat accumulator 5 recovers the high-temperature heat of the high-temperature and high-pressure gaseous carbon dioxide for heat storage, and liquefies the carbon dioxide through the water cooler 6 under high pressure, which not only saves storage space, but also has no requirements for geographical conditions, reduces the restrictions on geographical conditions, and is convenient for promotion and application; when releasing energy, the high-pressure gaseous carbon dioxide expands through the first expansion machine 10 to do work to produce low-temperature carbon dioxide that enters the cold accumulator 11 for cold storage, and realizes the storage of high-temperature thermal energy and low-temperature cold energy at the same time. In addition, the cold accumulator 11 uses ammonia liquid as a medium, and the ammonia liquid circulates between the heat accumulator 5 and the cold accumulator 11 and performs work to release energy to the outside, which has the advantages of small amount of medium and high efficiency. The above-mentioned high-temperature energy storage and release system has a simple structure and high energy utilization rate, which is convenient for large-scale and long-term storage of energy.

[0041] Example 2

[0042] The high-temperature energy storage and release method of this embodiment adopts the high-temperature energy storage and release system of Example 1 to store and release energy.

[0043] Energy storage includes: sending the low-temperature liquid carbon dioxide with a temperature of -70°C to -80°C in the low-temperature liquid carbon dioxide storage tank 1 to the first air evaporator 3 through the low-temperature pump 2 for gasification to form room-temperature gaseous carbon dioxide; the room-temperature gaseous carbon dioxide is pressurized by the compressor 4 to form a high-temperature and high-pressure gaseous carbon dioxide with a temperature of 450-500°C and a pressure of 7.0-8.0MPa; the high-temperature and high-pressure gaseous carbon dioxide is recovered through the heat accumulator 5 and cooled and liquefied through the water cooler 6 to form a high-pressure liquid carbon dioxide with a temperature of 20-25°C, and the high-pressure liquid carbon dioxide is sent to the high-pressure liquid carbon dioxide storage tank 7 for storage.

[0044] The energy release includes carbon dioxide energy release, and the carbon dioxide energy release includes: the high-pressure liquid carbon dioxide stored in the high-pressure liquid carbon dioxide storage tank 7 is throttled and reduced in pressure by the throttling and pressure-reducing valve 8 and then sent to the second air evaporator 9 for gasification to form high-pressure gaseous carbon dioxide, and the high-pressure gaseous carbon dioxide is sent to the first expansion machine 10 to perform work and release energy, and the low-temperature liquid carbon dioxide formed by the energy release is stored in the cold storage device 11 to form low-temperature liquid carbon dioxide, and the low-temperature liquid carbon dioxide is sent to the low-temperature liquid carbon dioxide storage tank 1 for storage.

[0045] Furthermore, the energy release also includes the release of ammonia liquid, and the release of ammonia liquid includes: pressurizing the ammonia liquid in the cold storage tank 11 through the booster pump 12 to form high-pressure ammonia liquid; sending the high-pressure ammonia liquid to the third air evaporator 13 for gasification to form high-pressure room-temperature ammonia gas, and the high-pressure room-temperature ammonia gas is heated by the heat storage tank 5 to form high-pressure and high-temperature ammonia gas, and the temperature of the high-pressure and high-temperature ammonia gas is 300-450°C, and the pressure is 2-10MPa; sending the high-pressure and high-temperature ammonia gas to the second expansion machine 14 to do work and release energy, and the low-pressure and low-temperature ammonia gas formed by the energy release enters the cold storage tank 11 to be cooled and condensed to form ammonia liquid and then continues to be recycled.

[0046] The actual operation results show that: the use of this method can effectively improve the cycle efficiency of liquid gas energy storage, and increase the cycle efficiency of liquid gas energy storage from about 50% to 65-70%; this method uses air energy to evaporate liquid carbon dioxide, which can utilize air energy and reduce electricity consumption; in addition, the energy storage medium of this method is stored in low-pressure liquid, which greatly reduces the storage space of the storage medium and reduces the storage pressure, greatly reducing the cost and space of the storage equipment.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high temperature energy storage and release system, characterized in that: It includes a carbon dioxide system and an ammonia liquid system. The carbon dioxide system includes a low-temperature liquid carbon dioxide storage tank, a first air evaporator, a compressor, a heat accumulator, a water cooler, a high-pressure liquid carbon dioxide storage tank, a second air evaporator, a first expander and a cold accumulator which are arranged in sequence. The ammonia liquid system includes a third air evaporator and a second expander. The inlet and outlet ends of the third air evaporator are connected to the cold accumulator and the heat accumulator respectively. The inlet and outlet ends of the second expander are connected to the heat accumulator and the cold accumulator respectively.

2. The high temperature energy storage and release system according to claim 1, characterized in that: A cryogenic pump is provided between the cryogenic liquid carbon dioxide storage tank and the first air evaporator.

3. The high temperature energy storage and release system according to claim 1, characterized in that: A throttling and pressure reducing valve is arranged between the high-pressure liquid carbon dioxide storage tank and the second air evaporator.

4. The high temperature energy storage and release system according to claim 1, characterized in that: A booster pump is provided between the cold storage device and the third air evaporator.

5. A high temperature energy storage and release method, characterized in that: The high-temperature energy storage and release system described in any one of claims 1 to 4 is used to store and release energy.

6. The high temperature energy storage and release method according to claim 5, characterized in that: Energy storage includes: The low-temperature liquid carbon dioxide in the low-temperature liquid carbon dioxide storage tank is sent to the first air evaporator for gasification to form room-temperature gaseous carbon dioxide, which is pressurized by a compressor to form high-temperature and high-pressure gaseous carbon dioxide, which is recovered by a heat accumulator and cooled and liquefied by a water cooler to form high-pressure liquid carbon dioxide, which is sent to a high-pressure liquid carbon dioxide storage tank for storage.

7. The high temperature energy storage and release method according to claim 6, characterized in that: The temperature of low-temperature liquid carbon dioxide is -70℃ to -80℃; the temperature of high-temperature and high-pressure gaseous carbon dioxide is 450-500℃ and the pressure is 7.0-8.0MPa; the temperature of high-pressure liquid carbon dioxide is 20-25℃.

8. The high temperature energy storage and release method according to claim 6, characterized in that: The energy release includes carbon dioxide energy release, and the carbon dioxide energy release includes: throttling and reducing the pressure of high-pressure liquid carbon dioxide and sending it to the second air evaporator for gasification to form high-pressure gaseous carbon dioxide, sending the high-pressure gaseous carbon dioxide to the first expansion machine for energy release, and the low-temperature liquid carbon dioxide formed by the energy release is stored in the cold storage device to form low-temperature liquid carbon dioxide, and the low-temperature liquid carbon dioxide is sent to the low-temperature liquid carbon dioxide storage tank for storage.

9. The high temperature energy storage and release method according to claim 6, characterized in that: The energy release includes the energy release of ammonia liquid, and the energy release of ammonia liquid includes: pressurizing the ammonia liquid in the cold storage device to form high-pressure ammonia liquid, sending the high-pressure ammonia liquid to the third air evaporator for vaporization to form high-pressure room-temperature ammonia gas, increasing the temperature of the high-pressure room-temperature ammonia gas through the heat storage device to form high-pressure and high-temperature ammonia gas, sending the high-pressure and high-temperature ammonia gas to the second expansion machine for energy release, and the low-pressure and low-temperature ammonia gas formed by the energy release enters the cold storage device for cooling and condensation to form ammonia liquid and then continues to be recycled.

10. The high temperature energy storage and release method according to claim 9, characterized in that: The temperature of high-pressure and high-temperature ammonia is 300-450°C and the pressure is 2-10MPa.

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