Pressure swing adsorption type compressed carbon dioxide energy storage system and operation method thereof

Abstract

The invention provides a pressure swing adsorption type compressed carbon dioxide energy storage system and an operation method thereof, and relates to the technical field of energy storage, the system comprises a pressure swing adsorption gas storage tank, a compression unit, an energy storage heat exchange unit, a high-pressure gas storage unit, an energy release heat exchange unit, an expansion unit and a pressure swing gas storage unit which are connected in sequence to form a closed circulation system, wherein the two heat exchange units are connected with the heat storage tank unit and the cold storage tank unit. The pressure swing adsorption gas storage tank mainly realizes efficient circulation of carbon dioxide through pressure change. By means of the pressure swing adsorption characteristic of an adsorbent material in the pressure swing adsorption tower, self-matching, namely self-consistent operation, of the temperature and pressure in the low-pressure gas storage tank can be achieved, adsorption heat in the system does not need to be guided out through a heat exchange unit, and the carbon dioxide gas amount needed by circulation of the energy storage system is effectively reduced; the energy storage and release response speed of the system is high, and the sensitivity of the system is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a pressure swing adsorption compressed carbon dioxide energy storage system and an operating method thereof. Background Art

[0002] Carbon dioxide has excellent physical properties such as high density, low viscosity, and good heat transfer performance. It is suitable as a working fluid in thermal cycles, and its density in the supercritical state is close to that of liquid. In comparison, compressed carbon dioxide energy storage technology has a higher energy storage density than traditional compressed gas energy storage, but carbon dioxide, as a greenhouse gas, needs to ensure a closed cycle, so the storage of carbon dioxide after expansion and energy release has become a new technical problem. At present, the commonly used low-pressure liquefied storage has problems such as high energy consumption and high cost, and flexible airbag storage has a large footprint and poor flexibility. In related technologies, energy storage is achieved through an adsorption-type compressed carbon dioxide energy storage system. However, at present, in the adsorption-type compressed carbon dioxide energy storage system, the variable temperature gas storage tank used for carbon dioxide adsorption and desorption often requires an additional heat exchange unit to achieve the desorption of the circulating working fluid carbon dioxide through temperature changes. The system response speed is limited by the heat and mass transfer rates of the adsorbent material, and the amount of circulating carbon dioxide required for the internal circulation of the system is large to achieve stable operation of the energy storage system. Summary of the Invention

[0003] The problem solved by the present invention is that in an adsorption-type compressed carbon dioxide energy storage system, a variable temperature gas storage tank used for carbon dioxide adsorption and desorption often requires an additional heat exchange unit to achieve desorption of the circulating working fluid carbon dioxide through temperature changes. The system response speed is limited by the heat and mass transfer rates of the adsorbent material, and a large amount of circulating carbon dioxide is required for the internal circulation of the system to achieve stable operation of the energy storage system.

[0004] To solve the above problems, the present invention provides a pressure swing adsorption compressed carbon dioxide energy storage system, comprising a pressure swing adsorption gas storage tank, a compression unit, an energy storage heat exchange unit, a high-pressure gas storage tank, an energy release heat exchange unit, and an expansion unit connected in sequence, wherein the inlet of the pressure swing adsorption gas storage tank is connected to the expansion unit via a first valve to form a closed carbon dioxide circulation loop; the outlet of the pressure swing adsorption gas storage tank is connected to the compression unit via a second valve; an adsorbent filling area is provided in the pressure swing adsorption gas storage tank, and an adsorbent is provided in the adsorbent filling area; a temperature sensor and a pressure sensor are provided in the pressure swing adsorption gas storage tank; It also includes a heat storage tank and a cold storage tank; the energy storage and heat exchange unit, the heat storage tank, the energy release heat exchange unit and the cold storage tank are connected in sequence, and the cold storage tank is connected to the energy storage and heat exchange unit to form a closed circulation loop.

[0005] Optionally, both the first valve and the second valve are electric valves.

[0006] Optionally, a controller is further included, and the controller is electrically connected to the temperature sensor, the pressure sensor, the first valve and the second valve respectively.

[0007] Optionally, the adsorbent is columnar activated carbon.

[0008] Optionally, a third valve is provided between the energy storage heat exchange unit and the cold storage tank, a fourth valve is provided between the cold storage tank and the energy release heat exchange unit, a fifth valve is provided between the energy release heat exchange unit and the heat storage tank, and a sixth valve is provided between the heat storage tank and the energy storage heat exchange unit.

[0009] Optionally, the high-temperature side inlet of the energy storage and heat exchange unit is connected to the outlet of the compression unit, and the low-temperature side outlet of the energy storage and heat exchange unit is connected to the inlet of the high-pressure gas storage tank.

[0010] Optionally, the low-temperature side inlet of the energy-releasing heat-exchanging unit is connected to the outlet of the high-pressure gas storage tank, and the high-temperature side outlet of the energy-releasing heat-exchanging unit is connected to the inlet of the expansion unit.

[0011] The present invention also provides an operating method of the pressure swing adsorption compressed carbon dioxide energy storage system as described above, comprising an energy storage process and an energy release process; The energy storage process includes: In an initial state, when the temperature in the pressure swing adsorption gas storage tank is a first temperature and the pressure is a first pressure, a second valve connected to the pressure swing adsorption gas storage tank is opened, and the pressure in the pressure swing adsorption gas storage tank continues to decrease. The carbon dioxide stored in the adsorbent absorbs the sensible heat of the adsorbent, desorbs from the micro-nano pore structure of the adsorbent, and then flows to the compression unit through the second valve. After being compressed into supercritical carbon dioxide, it enters the energy storage and heat exchange unit for cooling, and then enters the high-pressure gas storage tank for storage. During this process, the pressure and temperature in the pressure swing adsorption gas storage tank continue to decrease until the temperature and pressure in the pressure swing adsorption gas storage tank reach a second temperature and a second pressure. The energy release process includes: In an initial state, when the temperature and pressure in the pressure swing adsorption gas storage tank are the second temperature and the second pressure, the second valve is closed and the first valve is opened. The carbon dioxide stored in the high-pressure gas storage tank enters the energy-releasing heat exchange unit to increase in temperature, then enters the expansion unit to expand and perform work, and then enters the pressure swing adsorption gas storage tank for adsorption storage. During this process, the pressure and temperature in the pressure swing adsorption gas storage tank continue to increase until the temperature and pressure in the pressure swing adsorption gas storage tank reach the first temperature and the first pressure. The first temperature is 63° C. to 70° C., and the first pressure is 6.5 bar to 7.5 bar; the second temperature is 20° C. to 25° C., and the second pressure is 0.9 bar to 1.1 bar.

[0012] Optionally, the first temperature is 63° C., and the first pressure is 7 bar; the second temperature is 20° C., and the second pressure is 1 bar.

[0013] Optionally, during the energy storage process, the cold fluid in the cold storage tank flows into the energy storage heat exchange unit for heat exchange, and after absorbing heat, it becomes a high-temperature fluid and flows into the heat storage tank for storage; during the energy release process, the high-temperature fluid in the heat storage tank flows into the energy release heat exchange unit for heat exchange, and after releasing heat, it becomes a low-temperature fluid and flows into the cold storage tank for storage.

[0014] Compared with the related art, the energy storage process of the present invention is as follows: when the temperature in the pressure swing adsorption gas storage tank is a first temperature and the pressure is a first pressure (for example, 63°C, 7 bar), the second valve is opened and the first valve is closed, and the carbon dioxide stored in the pressure swing adsorption gas storage tank is compressed into supercritical carbon dioxide by the compression unit, enters the energy storage heat exchange unit for cooling, and then enters the high-pressure gas storage tank for storage until the temperature in the low-pressure gas storage tank reaches a second temperature and the pressure reaches a second pressure (for example, 20°C, 1 bar); the energy release process is as follows: when the temperature in the pressure swing adsorption gas storage tank is a second temperature and the pressure is a second pressure, the second valve is closed and the first valve is opened, and the carbon dioxide stored in the high-pressure gas storage tank enters the energy release heat exchange unit for heating, enters the expansion unit for expansion and work, and then enters the pressure swing adsorption gas storage tank for adsorption storage until the temperature in the pressure swing adsorption gas storage tank reaches the first temperature and the pressure reaches the first pressure; the energy storage process and the energy release process are connected together to form a closed cycle. Because the carbon dioxide adsorption capacity of the adsorbent in the pressure swing adsorption gas storage tank decreases with increasing temperature and increases with increasing pressure. The adsorbent in the pressure swing adsorption gas storage tank releases heat when adsorbing carbon dioxide, resulting in a decrease in the adsorption performance of the adsorbent. Therefore, in the present invention, the pressure swing adsorption gas storage tank adopts a pressure swing operation mode. Since a large amount of carbon dioxide after expansion and energy release continuously flows into the pressure swing adsorption gas storage tank, the internal pressure will continue to increase, promoting the rapid adsorption and storage of carbon dioxide in the micro-nano pores of the adsorbent. This process releases heat due to the adsorbent adsorbing carbon dioxide, resulting in an increase in temperature in the pressure swing adsorption gas storage tank, thereby inhibiting further adsorption and storage of carbon dioxide. However, due to the increase in pressure in the pressure swing adsorption gas storage tank, the adsorbent can avoid the result of inhibiting carbon dioxide adsorption by increasing temperature, and the adsorbent can further adsorb carbon dioxide. Therefore, the adsorption heat of this process can be stored in the adsorbent material in the pressure swing adsorption gas storage tank, and will not affect the further carbon dioxide adsorption process of the low-pressure gas storage tank. In summary, the pressure swing adsorption gas storage tank of the present invention has strong independence. By adopting the operating method of the present invention, self-matching of the temperature and pressure inside the pressure swing adsorption gas storage tank can be achieved, that is, self-consistent operation. No additional heat exchange unit is required for heat exchange, that is, there is no need to remove the adsorption heat generated by the adsorption of carbon dioxide in the pressure swing adsorption gas storage tank, which can effectively reduce the amount of carbon dioxide gas required for the circulation of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the structure of a pressure swing adsorption compressed carbon dioxide energy storage system in an embodiment of the present invention; Figure 2 It is the adsorption isotherm of columnar activated carbon from 0 bar to 10 bar (0℃ to 250℃).

[0016] Description of reference numerals: 1. Pressure swing adsorption gas storage tank; 2. Compression unit; 3. Energy storage and heat exchange unit; 4. High-pressure gas storage tank; 5. Energy release and heat exchange unit; 6. Expansion unit; 7. Heat storage tank; 8. Cold storage tank; 9. First valve; 10. Second valve; 11. Third valve; 12. Fourth valve; 13. Fifth valve; 14. Sixth valve. DETAILED DESCRIPTION

[0017] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0019] The term "including" and its variations used in this article are open inclusions, that is, "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or primary and secondary relationship. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. It should be noted that, Figure 1 The arrow in the middle indicates the direction of carbon dioxide flow in the adsorption-type compressed carbon dioxide energy storage system of the present invention. In the present invention, the cold storage tank is a device for storing cold energy, and the heat storage tank is a device for storing heat energy. Exemplarily, the energy storage medium used in the cold and heat storage tanks is a liquid fluid, such as water.

[0020] In related technologies, energy storage is achieved through an adsorption-type compressed carbon dioxide energy storage system. However, at present, in the adsorption-type compressed carbon dioxide energy storage system, the adsorption gas storage tank used for carbon dioxide adsorption and desorption often requires an additional heat exchange unit for heat exchange. Moreover, since the adsorption heat generated by carbon dioxide adsorption needs to be removed, a larger flow of carbon dioxide is required to clean the adsorbent to remove the adsorption heat. Therefore, a larger amount of circulating carbon dioxide is required for the internal circulation of the system to achieve stable operation of the energy storage system.

[0021] In view of the problems existing in the above-mentioned related technologies, such as Figure 1 As shown, an embodiment of the present invention provides an adsorption-type compressed carbon dioxide energy storage system, comprising a pressure swing adsorption gas storage tank 1, a compression unit 2, an energy storage and heat exchange unit 3, a high-pressure gas storage tank 4, an energy release and heat exchange unit 5, and an expansion unit 6 connected in sequence, and the inlet of the low-pressure gas storage tank 1 is connected to the expansion unit 6 through a first valve 9 to form a closed carbon dioxide circulation loop; the outlet of the pressure swing adsorption gas storage tank 1 is connected to the compression unit 2 through a second valve 10; an adsorbent filling area is provided in the pressure swing adsorption gas storage tank 1, and an adsorbent is provided in the adsorbent filling area; a temperature sensor (not shown in the figure) and a pressure sensor (not shown in the figure) are provided in the pressure swing adsorption gas storage tank 1; the temperature sensor and the pressure sensor are used to detect the temperature and pressure in the low-pressure gas storage tank 1, respectively; It also includes a heat storage tank 7 and a cold storage tank 8; the energy storage and heat exchange unit 3, the heat storage tank 7, the energy release heat exchange unit 5 and the cold storage tank 8 are connected in sequence, and the cold storage tank 8 is connected to the energy storage and heat exchange unit 3 to form a closed circulation loop.

[0022] In this embodiment, Figure 1 As shown, the pressure swing adsorption gas storage tank 1 is used for pressure swing and high-density storage of carbon dioxide, the compression unit 2 is used to compress the desorbed carbon dioxide in the pressure swing adsorption gas storage tank 1 into high-pressure and high-density supercritical carbon dioxide, the energy storage and heat exchange unit 3 is used to cool the supercritical carbon dioxide, the high-pressure gas storage tank 4 is used to store supercritical carbon dioxide, the energy release and heat exchange unit 5 is used to heat the supercritical carbon dioxide released from the high-pressure gas storage tank 4, and the expansion unit 6 is used to expand the supercritical carbon dioxide to do work. After the work is completed, the carbon dioxide enters the pressure swing adsorption gas storage tank 1 to be adsorbed and stored, completing a closed cycle.

[0023] In the embodiment of the present invention, illustratively, Figure 1As shown, the energy storage process is as follows: when the temperature in the low-pressure gas storage tank 1 is 63°C and the pressure is 7 bar, the second valve 10 is opened and the first valve 9 is closed. The carbon dioxide stored in the low-pressure gas storage tank 1 is desorbed from the adsorbent after decompression and heat absorption, and is compressed into supercritical carbon dioxide by the compression unit 2. It enters the energy storage heat exchange unit 3 for cooling, and then enters the high-pressure gas storage tank 4 for storage until the temperature in the pressure swing adsorption gas storage tank 1 is 20°C and the pressure is 1 bar; the energy release process is as follows: when the temperature in the pressure swing adsorption gas storage tank 1 is 20°C and the pressure is 1 bar, the second valve 10 is closed and the first valve 9 is opened. The carbon dioxide stored in the high-pressure gas storage tank 4 enters the energy release heat exchange unit 5 for heating, enters the expansion unit 6 for expansion and work, and then enters the pressure swing adsorption gas storage tank 1 for adsorption storage until the temperature in the pressure swing adsorption gas storage tank 1 is 63°C and the pressure is 7 bar.

[0024] Since the carbon dioxide adsorption capacity of the adsorbent in the pressure swing adsorption gas storage tank 1 decreases with increasing temperature and increases with increasing pressure. The adsorption of carbon dioxide by the adsorbent in the pressure swing adsorption gas storage tank 1 will release heat, resulting in a decrease in the adsorption performance of the adsorbent. Therefore, in the embodiment of the present invention, the pressure swing adsorption gas storage tank 1 adopts a pressure swing operation mode. During the process of adsorbing carbon dioxide, the internal pressure of the pressure swing adsorption gas storage tank 1 will continue to increase. Therefore, the adsorbent can avoid the result of inhibiting carbon dioxide adsorption due to the increase in temperature. The adsorbent can further adsorb carbon dioxide. Therefore, the adsorption heat of this process can be stored in the pressure swing adsorption gas storage tank 1 and will not affect the further carbon dioxide adsorption process of the pressure swing adsorption gas storage tank 1. In summary, the pressure swing adsorption gas storage tank 1 of the embodiment of the present invention has strong independence. By adopting the operating method of the embodiment of the present invention, the internal temperature and pressure of the pressure swing adsorption gas storage tank 1 can be self-matched, that is, self-consistent operation, without the need for an additional heat exchange unit for heat exchange. Therefore, there is no need to remove the adsorption heat generated by the adsorption of carbon dioxide in the pressure swing adsorption gas storage tank 1, which can effectively reduce the amount of carbon dioxide gas required for the energy storage system circulation.

[0025] In some embodiments of the present invention, illustratively, the adsorbent is columnar activated carbon. Figure 2 is the adsorption isotherm of the columnar activated carbon from 0 bar to 10 bar (0 ° C to 250 ° C), from Figure 2 It can be seen that in the energy storage system of the embodiment of the present invention, when the low-pressure gas storage tank 1 stores and releases energy between the state of temperature 63°C and pressure 7 bar and the state of temperature 20°C and pressure 1 bar, the amount of carbon dioxide gas required for the energy storage system circulation is small, only about 60 kg / m 3 , In some embodiments of the present invention, the pressure swing adsorption compressed carbon dioxide energy storage system further includes a controller (not shown). The first valve 9 and the second valve 10 are both electrically operated valves. The controller is electrically connected to the temperature sensor, the pressure sensor, the first valve 9, and the second valve 10, respectively. This enables automated control of the energy storage system.

[0026] In some embodiments of the present invention, Figure 1 As shown, a third valve 11 is provided between the energy storage heat exchange unit 3 and the cold storage tank 8, a fourth valve 12 is provided between the cold storage tank 8 and the energy release heat exchange unit 5, a fifth valve 13 is provided between the energy release heat exchange unit 5 and the heat storage tank 7, and a sixth valve 14 is provided between the heat storage tank 7 and the energy storage heat exchange unit 3. During the energy storage process, the third valve 11 and the sixth valve 14 are opened, and the fourth valve 12 and the fifth valve 13 are closed, allowing the cold fluid in the cold storage tank 8 to flow into the energy storage heat exchange unit 3 for heat exchange. After absorbing heat, the cold fluid becomes a high-temperature fluid and flows into the heat storage tank 7 for storage. During the energy release process, the third valve 11 and the sixth valve 14 are closed, and the fourth valve 12 and the fifth valve 13 are opened, allowing the high-temperature fluid in the heat storage tank 7 to flow into the energy release heat exchange unit 5 for heat exchange. After releasing heat, the high-temperature fluid becomes a low-temperature fluid and flows into the cold storage tank 8 for storage, thereby achieving a cycle between energy storage heat exchange, the energy release heat exchange unit 5, the external heat storage tank 77, and the cold storage tank 88.

[0027] In some embodiments of the present invention, Figure 1 As shown, the high-temperature side inlet of the energy storage heat exchange unit 3 is connected to the outlet of the compression unit 2, and the low-temperature side outlet of the energy storage heat exchange unit 3 is connected to the inlet of the high-pressure gas storage tank 4; the low-temperature side inlet of the energy release heat exchange unit 5 is connected to the outlet of the high-pressure gas storage tank 4, and the high-temperature side outlet of the energy release heat exchange unit 5 is connected to the inlet of the expansion unit 6.

[0028] The embodiment of the present invention further provides an operating method of the pressure swing adsorption compressed carbon dioxide energy storage system as described above, including an energy storage process and an energy release process; like Figure 1 As shown, the energy storage process includes: In the initial state, when the temperature in the pressure swing adsorption gas storage tank 1 is the first temperature and the pressure is the first pressure, the second valve 10 connected to the pressure swing adsorption gas storage tank 1 is opened, and the pressure in the pressure swing adsorption gas storage tank 1 continues to decrease. The carbon dioxide stored in the adsorbent absorbs the sensible heat of the adsorbent, desorbs from the micro-nano pore structure of the adsorbent, and flows to the compression unit 2 through the second valve 10. After being compressed into supercritical carbon dioxide, it enters the energy storage and heat exchange unit 3 for cooling, and then enters the high-pressure gas storage tank 4 for storage. During this process, the pressure and temperature in the pressure swing adsorption gas storage tank 1 continue to decrease until the temperature and pressure in the pressure swing adsorption gas storage tank 1 reach the second temperature and the second pressure; The energy release process includes: In the initial state, when the temperature and pressure in the pressure swing adsorption gas storage tank 1 are the second temperature and the second pressure, the second valve 10 is closed and the first valve 9 is opened. The carbon dioxide stored in the high-pressure gas storage tank 4 enters the energy-releasing heat exchange unit 5 to increase in temperature, then enters the expansion unit 6 to expand and perform work, and then enters the pressure swing adsorption gas storage tank 1 for adsorption storage. During this process, the pressure and temperature in the pressure swing adsorption gas storage tank 1 continue to increase until the temperature and pressure in the pressure swing adsorption gas storage tank 1 reach the first temperature and the first pressure. The first temperature is 63° C. to 70° C., and the first pressure is 6.5 bar to 7.5 bar; the second temperature is 20° C. to 25° C., and the second pressure is 0.9 bar to 1.1 bar.

[0029] Since the carbon dioxide adsorption capacity of the adsorbent in the pressure swing adsorption gas storage tank 1 decreases with increasing temperature and increases with increasing pressure. The adsorption of carbon dioxide by the adsorbent in the pressure swing adsorption gas storage tank 1 will release heat, resulting in a decrease in the adsorption performance of the adsorbent. Therefore, in the embodiment of the present invention, the pressure swing adsorption gas storage tank 1 adopts a pressure swing operation mode. During the process of adsorbing carbon dioxide, the internal pressure of the pressure swing adsorption gas storage tank 1 will continue to increase. Therefore, the adsorbent can avoid the result of inhibiting carbon dioxide adsorption due to the increase in temperature. The adsorbent can further adsorb carbon dioxide. Therefore, the adsorption heat of this process can be stored in the low-pressure gas storage tank 1 and will not affect the further carbon dioxide adsorption process of the pressure swing adsorption gas storage tank 1. In summary, the pressure swing adsorption gas storage tank 1 of the embodiment of the present invention has strong independence. By adopting the operating method of the embodiment of the present invention, the internal temperature and pressure of the pressure swing adsorption gas storage tank 1 can be self-matched, that is, self-consistent operation, without the need for an additional heat exchange unit for heat exchange, that is, there is no need to remove the adsorption heat generated by the adsorption of carbon dioxide in the pressure swing adsorption gas storage tank 1, which can effectively reduce the amount of carbon dioxide gas required for the energy storage system cycle.

[0030] In some embodiments of the present invention, preferably, the first temperature is 63° C., and the first pressure is 7 bar; the second temperature is 20° C., and the second pressure is 1 bar.

[0031] In some embodiments of the present invention, Figure 1 As shown, during the energy storage process, the cold fluid in the cold storage tank 8 flows into the energy storage heat exchange unit 3 for heat exchange, and after absorbing heat, it becomes a high-temperature fluid and flows into the heat storage tank 7 for storage; during the energy release process, the high-temperature fluid in the heat storage tank 7 flows into the energy release heat exchange unit 5 for heat exchange, and after releasing heat, it becomes a low-temperature fluid and flows into the cold storage tank 8 for storage.

[0032] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A pressure swing adsorption compressed carbon dioxide energy storage system, characterized in that: The invention comprises a pressure swing adsorption gas storage tank (1), a compression unit (2), an energy storage and heat exchange unit (3), a high-pressure gas storage tank (4), an energy release and heat exchange unit (5), and an expansion unit (6) connected in sequence, wherein the expansion unit (6) is connected to the inlet of the pressure swing adsorption gas storage tank (1) via a first valve (9) to form a closed carbon dioxide circulation loop; the outlet of the pressure swing adsorption gas storage tank (1) is connected to the compression unit (2) via a second valve (10); an adsorbent filling area is provided in the pressure swing adsorption gas storage tank (1), and an adsorbent is provided in the adsorbent filling area; and a temperature sensor and a pressure sensor are provided in the low-pressure gas storage tank (1); It also includes a heat storage tank (7) and a cold storage tank (8); the energy storage heat exchange unit (3), the heat storage tank (7), the energy release heat exchange unit (5) and the cold storage tank (8) are connected in sequence, and the cold storage tank (8) is connected to the energy storage heat exchange unit (3) to form a closed circulation loop.

2. The pressure swing adsorption compressed carbon dioxide energy storage system according to claim 1, characterized in that: The first valve (9) and the second valve (10) are both electric valves.

3. The pressure swing adsorption compressed carbon dioxide energy storage system according to claim 2, characterized in that: It also includes a controller, which is electrically connected to the temperature sensor, the pressure sensor, the first valve (9) and the second valve (10) respectively.

4. The pressure swing adsorption compressed carbon dioxide energy storage system according to claim 1, characterized in that: The adsorbent is columnar activated carbon suitable for pressure swing adsorption.

5. The pressure swing adsorption compressed carbon dioxide energy storage system according to claim 1, characterized in that: A third valve (11) is provided between the energy storage heat exchange unit (3) and the cold storage tank (8), a fourth valve (12) is provided between the cold storage tank (8) and the energy release heat exchange unit (5), a fifth valve (13) is provided between the energy release heat exchange unit (5) and the heat storage tank (7), and a sixth valve (14) is provided between the heat storage tank (7) and the energy storage heat exchange unit (3).

6. The pressure swing adsorption compressed carbon dioxide energy storage system according to claim 1, characterized in that: The high-temperature side inlet of the energy storage and heat exchange unit (3) is connected to the outlet of the compression unit (2), and the low-temperature side outlet of the energy storage and heat exchange unit (3) is connected to the inlet of the high-pressure gas storage tank (4).

7. The pressure swing adsorption compressed carbon dioxide energy storage system according to claim 1, characterized in that: The low-temperature side inlet of the energy-releasing heat-exchanging unit (5) is connected to the outlet of the high-pressure gas storage tank (4), and the high-temperature side outlet of the energy-releasing heat-exchanging unit (5) is connected to the inlet of the expansion unit (6).

8. An operating method of a pressure swing adsorption compressed carbon dioxide energy storage system according to any one of claims 1 to 7, characterized in that: Including energy storage process and energy release process; The energy storage process includes: In the initial state, when the temperature in the pressure swing adsorption gas storage tank (1) is the first temperature and the pressure is the first pressure, the second valve (10) connected to the pressure swing adsorption gas storage tank (1) is opened, and the pressure in the pressure swing adsorption gas storage tank (1) continues to decrease, and the carbon dioxide stored in the adsorbent absorbs the sensible heat of the adsorbent, desorbs from the micro-nano pore structure of the adsorbent, and flows to the compression unit (2) through the second valve (10), is compressed into supercritical carbon dioxide, enters the energy storage and heat exchange unit (3) for cooling, and then enters the high-pressure gas storage tank (4) for storage. During this process, the pressure in the pressure swing adsorption gas storage tank (1) continues to decrease, and the temperature continues to decrease until the temperature in the pressure swing adsorption gas storage tank (1) reaches the second temperature and the pressure reaches the second pressure; The energy release process includes: In the initial state, when the temperature in the pressure swing adsorption gas storage tank (1) is the second temperature and the pressure is the second pressure, the second valve (10) is closed and the first valve (9) is opened, and the carbon dioxide stored in the high-pressure gas storage tank (4) enters the energy release heat exchange unit (5) to increase in temperature, then enters the expansion unit (6) to expand and perform work, and then enters the pressure swing adsorption gas storage tank (1) for adsorption storage. During this process, the pressure and temperature in the pressure swing adsorption gas storage tank (1) continue to increase until the temperature and pressure in the pressure swing adsorption gas storage tank (1) reach the first temperature and the first pressure; The first temperature is 63° C. to 70° C., and the first pressure is 6.5 bar to 7.5 bar; the second temperature is 20° C. to 25° C., and the second pressure is 0.9 bar to 1.1 bar.

9. The operating method of the pressure swing adsorption compressed carbon dioxide energy storage system according to claim 8, characterized in that: The first temperature is 63° C., and the first pressure is 7 bar; the second temperature is 20° C., and the second pressure is 1 bar.

10. The operating method of the pressure swing adsorption compressed carbon dioxide energy storage system according to claim 8, characterized in that: During the energy storage process, the cold fluid in the cold storage tank (8) flows into the energy storage heat exchange unit (3) for heat exchange, and after absorbing heat, it becomes a high-temperature fluid and flows into the heat storage tank (7) for storage; during the energy release process, the high-temperature fluid in the heat storage tank (7) flows into the energy release heat exchange unit (5) for heat exchange, and after releasing heat, it becomes a low-temperature fluid and flows into the cold storage tank (8) for storage.

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