Compressed carbon dioxide energy storage power station system and operation method in cold and severe cold regions

Abstract

The present invention discloses a compressed carbon dioxide energy storage power station system and operating method for cold and extremely cold regions, belonging to the technical field of compressed carbon dioxide energy storage power stations. The system comprises an air compression device and a high-temperature chilled water device. The air compression device comprises an air tank, a first-stage compressor, a first interstage heat exchanger, a second-stage compressor, a second interstage heat exchanger, a third-stage compressor, a third interstage heat exchanger, a liquefier, and a liquid carbon dioxide storage tank, which are connected in sequence. The water circulation pipeline of the interstage heat exchanger is respectively connected to a low-temperature heat medium water tank and a high-temperature heat medium water tank. The high-temperature chilled water device comprises a closed cooling tower and a closed cold water expansion tank. The chilled water outlet of the closed cooling tower is connected to the liquefier water inlet via a high-temperature chilled water circulation pump, and the chilled water inlet of the closed cooling tower is connected to the closed cold water expansion tank and the liquefier water outlet. The present invention uses a natural cold source to liquefy carbon dioxide, eliminating the refrigeration system, increasing the heat storage temperature of the compressed carbon dioxide energy storage power station, and improving the power station's electrical efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed carbon dioxide energy storage power stations, in particular to a compressed carbon dioxide energy storage power station system and an operating method in cold and extremely cold regions. Background Art

[0002] The comprehensive market-oriented development of new energy storage is accelerating, the independent market entity status of new energy storage has been clarified, and the power market system has been continuously improved, providing a good environment for new energy storage to participate in power market transactions. Various new energy storage technologies have made significant progress.

[0003] Compressed carbon dioxide energy storage, a key component of new energy storage technologies, is an effective means of improving the regulation capabilities of power systems and is currently undergoing commercial rollout. With technological advancements, compressed air energy storage power stations are placing higher demands on efficiency and cost. Heat utilization and chiller plant power consumption are key factors limiting the efficiency of compressed carbon dioxide energy storage. Increasing heat storage temperature and reducing refrigeration consumption can improve the overall efficiency of power plants, thereby enhancing their economical operation.

[0004] At present, China uses liquefied compressed carbon dioxide for energy storage. Two-stage compression compresses carbon dioxide to about 8MPa, and a refrigerator is used to generate chilled water to liquefy carbon dioxide. The heat on the expansion power generation side comes from the compression heat stored in the compression process. The compressor inlet temperature is cooled to 30°C with chilled water. Due to the critical point pressure of carbon dioxide, the heat storage temperature is difficult to increase, and it is difficult to achieve "low pressure and high temperature" operation. The system efficiency cannot be further improved. In addition, the refrigerator consumes a lot of electricity and has low energy utilization, making it difficult to promote it further. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a compressed carbon dioxide energy storage power station system and operation method for cold and extremely cold regions. The system uses a natural cold source to liquefy carbon dioxide, which can eliminate the refrigeration system, increase the heat storage temperature of the compressed carbon dioxide energy storage power station, improve the power efficiency of the power station, reduce the power consumption rate of the plant, reduce the amount of cooling water, reduce the number of heat exchangers, reduce the cost and floor space of the heat exchangers, simplify the compressed carbon dioxide energy storage system, improve the system robustness, and reduce the system pressure loss.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A compressed carbon dioxide energy storage power station system for cold and severe cold regions, comprising an air compression device and a high-temperature chilled water device;

[0008] The air compression device includes an air tank, a first-stage compressor, a first-stage heat exchanger, a second-stage compressor, a second-stage heat exchanger, a third-stage compressor, a third-stage heat exchanger, a liquefier, and a liquid carbon dioxide storage tank connected in sequence; the water circulation pipelines of the first-stage heat exchanger, the second-stage heat exchanger, and the third-stage heat exchanger are respectively connected to the low-temperature heat medium water tank and the high-temperature heat medium water tank;

[0009] The high-temperature chilled water device adopts a closed cold water closed circulation, including a closed cooling tower and a closed cold water expansion tank; the chilled water outlet of the closed cooling tower is connected to the liquefier water inlet through a high-temperature chilled water circulation pump, and the chilled water inlet of the closed cooling tower is connected to the closed cold water expansion tank and the liquefier water outlet.

[0010] A further improvement of the technical solution of the present invention is that: a first shut-off valve is provided on the outlet pipeline of the gas warehouse, a second shut-off valve is provided on the inlet pipeline of the liquid carbon dioxide storage tank, a third shut-off valve and a fourth shut-off valve are provided on the air inlet and liquid outlet pipelines of the liquefier respectively, the outer sides of the third shut-off valve and the fourth shut-off valve are connected to the liquid outlet branch and a fifth shut-off valve is provided, and a sixth shut-off valve is provided on the water supply pipeline of the closed cold water expansion tank.

[0011] A method for operating a compressed carbon dioxide energy storage power station system in cold and severe cold regions comprises the following steps:

[0012] S1, non-refrigerated compressed carbon dioxide energy storage;

[0013] The corresponding shut-off valve of S11 is actuated, and the energy storage mode is turned on. The carbon dioxide enters the first-stage compressor, the first-stage inter-stage heat exchanger, the second-stage compressor, the second-stage inter-stage heat exchanger, the third-stage compressor, the third-stage inter-stage heat exchanger, and the liquefier in sequence, and is converted into liquid carbon dioxide and stored in the liquid carbon dioxide storage tank.

[0014] S12 compressor has optimized distribution ratio at each stage;

[0015] The S13 interstage heat exchanger cools the exhaust gas from each stage of the compressor;

[0016] S14 replenishes the closed cold water expansion tank, and the high-temperature chilled water device cools the liquefier;

[0017] S2, no refrigeration compression carbon dioxide release energy;

[0018] The corresponding shut-off valve of S21 is actuated, and the energy release mode is turned on. The carbon dioxide enters the third interstage heat exchanger, the third-stage compressor, the second interstage heat exchanger, the second-stage compressor, the first interstage heat exchanger, the first-stage compressor from the liquid carbon dioxide storage tank in sequence, and is stored in the gas warehouse;

[0019] S22 expander each stage ratio optimization distribution;

[0020] The S23 third interstage heat exchanger vaporizes the liquid carbon dioxide, and the interstage heat exchanger heats the exhaust gas of each stage of compressor.

[0021] A further improvement of the technical solution of the present invention is that: in S11, when storing energy, the first shut-off valve, the second shut-off valve, the third shut-off valve and the fourth shut-off valve are opened, and the fifth shut-off valve is closed. After passing through the first shut-off valve, the carbon dioxide enters the first-stage compressor, the first inter-stage heat exchanger, the second-stage compressor, the second inter-stage heat exchanger, the third-stage compressor, and the third inter-stage heat exchanger in sequence, and is condensed in the liquefier and then sent to the liquid carbon dioxide storage tank for storage.

[0022] A further improvement of the technical solution of the present invention is that in S12, the pressure ratio of each stage of the compressor is distributed as follows:

[0023] ;

[0024] Among them, N1, N2, and N3 are the pressure ratios of the first, second, and third stage compressors respectively; T c is the heat storage temperature of the carbon dioxide energy storage power station, ranging from 393 to 423 K; T1 is the inlet temperature of the first-stage compressor; is the adiabatic efficiency of the first-stage compressor; β is the liquefaction redundancy coefficient, ranging from 1.05 to 1.15; P cr is the critical pressure ratio of carbon dioxide.

[0025] A further improvement of the technical solution of the present invention is that: in S13, the low-temperature heat medium water circulation pump is turned on, and the low-temperature heat medium water is respectively sent to the first inter-stage heat exchanger, the second inter-stage heat exchanger, and the third inter-stage heat exchanger through the low-temperature heat medium water circulation pump, and heat is exchanged with the exhaust gas of each stage of compressor in the heat exchanger. After the low-temperature heat medium water absorbs heat and rises in temperature, it is sent to the high-temperature heat medium water tank for storage.

[0026] The technical solution of the present invention is further improved in that: in S14, the high temperature chilled water device adopts a closed cold water closed cycle, opens the sixth shut-off valve, replenishes water to the closed cold water expansion tank and then enters the compressed carbon dioxide energy storage power station system, and sets the closed cold water expansion tank to absorb the volume expansion of the temperature change, and uses the closed cooling tower to generate T g The high temperature chilled water at the temperature is sent to the liquefier to condense the carbon dioxide, and then the temperature is raised to T h Return to the closed cooling tower;

[0027] ;

[0028] in, T g is the high-temperature chilled water supply temperature, in °C; T his the high-temperature chilled water return temperature, in °C; T cr is the critical temperature of carbon dioxide, in °C; T dc is the liquefier end difference, ranging from 5-7°C; T ry is the liquefaction redundancy temperature, with a value range of 1-2°C; T lq The cooling end difference of the closed cooling tower is in the range of 8-12℃; T aq It is the safe temperature of the closed cooling tower, and the value range is 1-3℃.

[0029] A further improvement of the technical solution of the present invention is that: in S21, when releasing energy, the first shut-off valve, the second shut-off valve and the fifth shut-off valve are opened, and the third shut-off valve and the fourth shut-off valve are closed. After passing through the second shut-off valve and the fifth shut-off valve, the liquid carbon dioxide enters the third inter-stage heat exchanger, the third-stage compressor, the second inter-stage heat exchanger, the second-stage compressor, the first inter-stage heat exchanger, and the first-stage compressor in sequence for heat exchange and work, and is then sent to the gas storage for storage.

[0030] A further improvement of the technical solution of the present invention is that in S22, in order to make the compression energy storage and expansion energy release heat exchangers share a set of heat exchangers, the expansion ratios of the expanders at each stage are distributed as follows:

[0031] ;

[0032] Among them, N4, N5, and N6 are the expansion ratios of the expander high-pressure cylinder, intermediate-pressure cylinder, and low-pressure cylinder; m1 is the matching coefficient between the expander low-pressure cylinder and the first-stage compressor, and the value range is 0.9-0.95; m2 is the resistance reduction coefficient of the high-pressure cylinder and the intermediate-pressure cylinder, and the value range is 0.98-0.99; P0 is the inlet pressure of the expander high-pressure cylinder; and P1 is the gas tank storage pressure.

[0033] A further improvement of the technical solution of the present invention is that: in S23, the high-temperature heat medium water circulation pump is turned on, and the high-temperature heat medium water is respectively sent to the third inter-stage heat exchanger, the second inter-stage heat exchanger, and the first inter-stage heat exchanger through the high-temperature heat medium water circulation pump to exchange heat with the exhaust gas of each stage of compressor, and the liquid carbon dioxide is vaporized in the heat exchanger in the third inter-stage heat exchanger. After the high-temperature heat medium water releases heat and cools down, it is sent to the low-temperature heat medium water tank for storage.

[0034] Due to the adoption of the above technical solution, the technical advancements achieved by the present invention are:

[0035] 1. In the present invention, only an interstage heat exchanger is provided on the compression side, eliminating the need for an additional cold source to cool the compressed carbon dioxide. This reduces the cost and footprint of the heat exchanger, reducing the heat exchanger footprint by 5% and the heat exchanger cost by 10%.

[0036] 2. The present invention sets up a high-temperature chilled water system, which uses the high-temperature chilled water generated by the closed cooling tower in cold and extremely cold regions as the cooling source for liquefied carbon dioxide. There is no need to set up a refrigerator to generate chilled water, which reduces the power consumption of the power plant. The system is cooled by high-temperature chilled water. The use of this system can reduce the power consumption rate by 60-70% and reduce the cost of the power plant by 10%. It is suitable for use in cold and extremely cold regions.

[0037] 3. This invention improves the heat utilization rate of the system. The heat of each compressor stage is utilized. The temperature of carbon dioxide entering the secondary and tertiary compressors can be increased by 15-25°C, and the compressor exhaust temperature can be increased by 20-35°C. While maintaining the heat storage temperature, the system parameters and electrical efficiency can be improved, achieving "low-pressure and high-temperature" operation of the system.

[0038] 4. The compressed carbon dioxide energy storage in the present invention adopts constant pressure operation. In order to match the heat at each level, the compression and expansion temperatures of each level are approximately the same. Three-stage compression and three-stage expansion are adopted, which can improve the electrical efficiency by 1%.

[0039] 5. In the present invention, the number of compression and expansion stages is the same, and compression energy storage and expansion energy release share a set of heat exchangers, which can reduce the heat exchanger footprint by 40% and reduce the heat exchanger cost by 30%.

[0040] 6. The whole system of the present invention is closed-loop and can adopt carbon steel structure as a whole, which can reduce the cost of heat exchanger by 30%.

[0041] 7. The system of the present invention is reliable and easy to implement, and is suitable for promotion and application in cold and extremely cold regions. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is the compressed carbon dioxide energy storage power station system for cold and severe cold regions in the present invention;

[0043] Among them, 1. Gas storage, 2. First-stage compressor, 3. First-stage heat exchange, 4. Second-stage compressor, 5. Second-stage heat exchanger, 6. Third-stage compressor, 7. Third-stage heat exchanger, 8. Liquefier, 9. Liquid carbon dioxide storage tank, 10. Low-temperature heat medium water tank, 11. High-temperature heat medium water tank, 12. Closed cooling tower, 13. Closed cold water expansion tank, 14. High-temperature chilled water circulation pump, 15. First shut-off valve, 16. Second shut-off valve, 17. Third shut-off valve, 18. Fourth shut-off valve, 19. Fifth shut-off valve, 20. Sixth shut-off valve. DETAILED DESCRIPTION

[0044] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0045] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0046] Furthermore, the terms "first," "second," etc. are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified with "first," "second," etc. may explicitly or implicitly include at least one such feature. In the description of the present invention, "several" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0047] like Figure 1 As shown, the compressed carbon dioxide energy storage power station system includes an air compression device and a high-temperature chilled water device;

[0048] The air compression device includes an air tank 1, a first-stage compressor 2, a first interstage heat exchanger 3, a second-stage compressor 4, a second interstage heat exchanger 5, a third-stage compressor 6, a third interstage heat exchanger 7, a liquefier 8 and a liquid carbon dioxide storage tank 9, which are connected in sequence; the water circulation pipelines of the first interstage heat exchanger 3, the second interstage heat exchanger 5 and the third interstage heat exchanger 7 are respectively connected to a low-temperature heat medium water tank 10 and a high-temperature heat medium water tank 11;

[0049] The high-temperature chilled water device adopts a closed cold water closed cycle, including a closed cooling tower 12 and a closed cold water expansion tank 13; the chilled water outlet of the closed cooling tower 12 is connected to the water inlet of the liquefier 8 through a high-temperature chilled water circulation pump 14, and the chilled water inlet of the closed cooling tower 12 is connected to the closed cold water expansion tank 13 and the water outlet of the liquefier 8;

[0050] A first shut-off valve 15 is provided on the outlet pipeline of the gas warehouse 1, a second shut-off valve 16 is provided on the inlet pipeline of the liquid carbon dioxide storage tank 9, a third shut-off valve 17 and a fourth shut-off valve 18 are respectively provided on the air inlet and liquid outlet pipelines of the liquefier 8, the third shut-off valve 17 and the fourth shut-off valve 18 are connected to the liquid outlet branch on the outside and a fifth shut-off valve 19 is provided, and a sixth shut-off valve 20 is provided on the water supply pipeline of the closed cold water expansion tank 13.

[0051] The method for operating a compressed carbon dioxide energy storage power station system in cold and severe cold regions comprises the following steps:

[0052] S1, non-refrigerated compressed carbon dioxide energy storage;

[0053] The corresponding shut-off valve in S11 is actuated, and the energy storage mode is turned on. The carbon dioxide enters the first-stage compressor 2, the first interstage heat exchanger 3, the second-stage compressor 4, the second interstage heat exchanger 5, the third-stage compressor 6, the third interstage heat exchanger 7, and the liquefier 8 from the gas tank 1 in sequence, and is converted into liquid carbon dioxide and stored in the liquid carbon dioxide storage tank 9.

[0054] During energy storage, the first shut-off valve 15, the second shut-off valve 16, the third shut-off valve 17, and the fourth shut-off valve 18 are opened, and the fifth shut-off valve 19 is closed. After passing through the first shut-off valve 15, the carbon dioxide sequentially enters the first-stage compressor 2, the first inter-stage heat exchanger 3, the second-stage compressor 4, the second inter-stage heat exchanger 5, the third-stage compressor 6, and the third inter-stage heat exchanger 7. After being condensed in the liquefier 8, the carbon dioxide is sent to the liquid carbon dioxide storage tank 9 for storage.

[0055] S12 compressor has optimized distribution ratio at each stage;

[0056] The pressure ratio distribution of each stage of the compressor is as follows:

[0057] ;

[0058] Among them, N1, N2, and N3 are the pressure ratios of the first, second, and third stage compressors respectively; T c is the heat storage temperature of the carbon dioxide energy storage power station, ranging from 393 to 423 K; T1 is the inlet temperature of the first stage compressor 2; is the adiabatic efficiency of the first-stage compressor 2; β is the liquefaction redundancy coefficient, ranging from 1.05 to 1.15; P cr is the critical pressure ratio of carbon dioxide;

[0059] The S13 interstage heat exchanger cools the exhaust gas from each stage of the compressor;

[0060] The low-temperature heat medium water circulation pump is turned on. The low-temperature heat medium water is sent to the first inter-stage heat exchanger 3, the second inter-stage heat exchanger 5, and the third inter-stage heat exchanger 7 respectively through the low-temperature heat medium water circulation pump. In the heat exchanger, the low-temperature heat medium water exchanges heat with the exhaust gas of each stage of the compressor. After absorbing heat and rising in temperature, the low-temperature heat medium water is sent to the high-temperature heat medium water tank 11 for storage.

[0061] S14 replenishes water to the closed cold water expansion tank 13, and the high-temperature chilled water device cools the liquefier 8;

[0062] The high temperature chilled water device adopts closed cold water closed circulation, opens the sixth shut-off valve 20, replenishes water to the closed cold water expansion tank 13 and then enters the compressed carbon dioxide energy storage power station system, sets the closed cold water expansion tank 13 to absorb the volume expansion of temperature change, and uses the closed cooling tower 12 to generate T gThe high temperature chilled water at the temperature is sent to the liquefier 8 to condense the carbon dioxide, and then the temperature is raised to T h Send back to the closed cooling tower 12;

[0063] ;

[0064] in, T g is the high-temperature chilled water supply temperature, in °C; T h is the high-temperature chilled water return temperature, in °C; T cr is the critical temperature of carbon dioxide, in °C; T dc The temperature difference at the liquefier 8 end is in the range of 5-7℃; T ry is the liquefaction redundancy temperature, with a value range of 1-2°C; T lq The cooling end difference of the closed cooling tower 12 is in the range of 8-12℃; T aq It is the safety temperature of the closed cooling tower 12, and the value range is 1-3℃.

[0065] S2, no refrigeration compression carbon dioxide release energy;

[0066] S21 The corresponding shut-off valve is actuated, and the energy release mode is turned on. Carbon dioxide enters the third interstage heat exchanger 7, the third-stage compressor 6, the second interstage heat exchanger 5, the second-stage compressor 4, the first interstage heat exchanger 3, the first-stage compressor 2 from the liquid carbon dioxide storage tank 9 in sequence, and is stored in the gas warehouse 1;

[0067] When releasing energy, the first shut-off valve 15, the second shut-off valve 16 and the fifth shut-off valve 19 are opened, and the third shut-off valve 17 and the fourth shut-off valve 18 are closed. The liquid carbon dioxide passes through the second shut-off valve 16 and the fifth shut-off valve 19 and then enters the third inter-stage heat exchanger 7, the third-stage compressor 6, the second inter-stage heat exchanger 5, the second-stage compressor 4, the first inter-stage heat exchanger 3, and the first-stage compressor 2 in sequence to exchange heat and perform work. After performing work, the liquid carbon dioxide is sent to the gas warehouse 1 for storage.

[0068] S22 expander each stage ratio optimization distribution;

[0069] In order to make the compression energy storage and expansion energy release heat exchangers share a set of heat exchangers, the compression ratio and expansion ratio of each stage during compression energy storage and expansion energy release are similar. The expansion ratio of each stage of the expander is distributed as follows:

[0070] ;

[0071] Among them, N4, N5, and N6 are the expansion ratios of the expander high-pressure cylinder, intermediate-pressure cylinder, and low-pressure cylinder; m1 is the matching coefficient between the expander low-pressure cylinder and the first-stage compressor 2, and the value range is 0.9-0.95; m2 is the resistance reduction coefficient of the high-pressure cylinder and the intermediate-pressure cylinder, and the value range is 0.98-0.99; P0 is the inlet pressure of the expander high-pressure cylinder; P1 is the storage pressure of the gas tank 1;

[0072] S23 The third interstage heat exchanger 7 vaporizes the liquid carbon dioxide and heats the exhaust gas of each stage compressor;

[0073] The high-temperature heat medium water circulation pump is turned on, and the high-temperature heat medium water is respectively sent to the third inter-stage heat exchanger 7, the second inter-stage heat exchanger 5, and the first inter-stage heat exchanger 3 through the high-temperature heat medium water circulation pump to exchange heat with the exhaust gas of each stage of compressors, and the liquid carbon dioxide is vaporized in the heat exchanger 7 of the third inter-stage heat exchanger. After the high-temperature heat medium water releases heat and cools down, it is sent to the low-temperature heat medium water tank 10 for storage.

[0074] In summary, the present invention uses a natural cold source to liquefy carbon dioxide, which can eliminate the refrigeration system, increase the heat storage temperature of the compressed carbon dioxide energy storage power station, improve the power station's electrical efficiency, reduce the plant's power consumption rate, reduce the amount of cooling water, reduce the number of heat exchangers, reduce the cost and floor space of the heat exchanger, simplify the compressed carbon dioxide energy storage system, improve the system's robustness, and reduce the system's pressure loss.

Claims

1. A method for operating a compressed carbon dioxide energy storage power station system in cold and severe cold regions, characterized by: The following steps are involved: S1, non-refrigerated compressed carbon dioxide energy storage; S11 The corresponding shut-off valve is actuated, and the energy storage mode is turned on. The carbon dioxide enters the first-stage compressor (2), the first inter-stage heat exchanger (3), the second-stage compressor (4), the second inter-stage heat exchanger (5), the third-stage compressor (6), the third inter-stage heat exchanger (7), and the liquefier (8) from the gas tank (1) in sequence, and is converted into liquid carbon dioxide and stored in the liquid carbon dioxide storage tank (9); S12 compressor has optimized distribution of each level ratio; In S12, the pressure ratio of each stage of the compressor is distributed as follows: Among them, N1, N2, and N3 are the pressure ratios of the first, second, and third stage compressors respectively; T c is the heat storage temperature of the carbon dioxide energy storage power station, ranging from 393 to 423 K; T1 is the inlet temperature of the first stage compressor (2); η is the adiabatic efficiency of the first stage compressor (2); β is the liquefaction redundancy coefficient, ranging from 1.05 to 1.15; P cr is the critical pressure ratio of carbon dioxide; The S13 interstage heat exchanger cools the exhaust gas from each stage of the compressor; S14 replenishes the closed cold water expansion tank (13) with water, and the high-temperature chilled water device cools the liquefier (8); S2, no refrigeration compression carbon dioxide release energy; S21 The corresponding shut-off valve is actuated, and the energy release mode is turned on. Carbon dioxide enters the third interstage heat exchanger (7), the third-stage compressor (6), the second interstage heat exchanger (5), the second-stage compressor (4), the first interstage heat exchanger (3), the first-stage compressor (2) from the liquid carbon dioxide storage tank (9) in sequence, and is stored in the gas warehouse (1); S22 expander each stage ratio optimization distribution; S23 The third interstage heat exchanger (7) vaporizes the liquid carbon dioxide, and the interstage heat exchanger heats the exhaust gas of each stage compressor; The cold and severe cold region compressed carbon dioxide energy storage power station system includes an air compression device and a high-temperature chilled water device; The air compression device comprises an air silo (1), a first-stage compressor (2), a first inter-stage heat exchanger (3), a second-stage compressor (4), a second inter-stage heat exchanger (5), a third-stage compressor (6), a third inter-stage heat exchanger (7), a liquefier (8) and a liquid carbon dioxide storage tank (9) which are connected in sequence; the water circulation pipelines of the first inter-stage heat exchanger (3), the second inter-stage heat exchanger (5) and the third inter-stage heat exchanger (7) are respectively connected to a low-temperature heat medium water tank (10) and a high-temperature heat medium water tank (11); The high-temperature chilled water device adopts a closed cold water closed cycle, comprising a closed cooling tower (12) and a closed cold water expansion tank (13); the chilled water outlet of the closed cooling tower (12) is connected to the water inlet of the liquefier (8) through a high-temperature chilled water circulation pump (14), and the chilled water inlet of the closed cooling tower (12) is connected to the closed cold water expansion tank (13) and the water outlet of the liquefier (8); A first shut-off valve (15) is provided on the outlet pipeline of the gas tank (1), a second shut-off valve (16) is provided on the inlet pipeline of the liquid carbon dioxide storage tank (9), a third shut-off valve (17) and a fourth shut-off valve (18) are provided on the gas inlet and liquid outlet pipelines of the liquefier (8), respectively, the outer sides of the third shut-off valve (17) and the fourth shut-off valve (18) are connected to the liquid outlet branch and a fifth shut-off valve (19) is provided, and a sixth shut-off valve (20) is provided on the water supply pipeline of the closed cold water expansion tank (13).

2. The method for operating a compressed carbon dioxide energy storage power station system in cold and severe cold regions according to claim 1, characterized in that: In S11, when energy is stored, the first shut-off valve (15), the second shut-off valve (16), the third shut-off valve (17) and the fourth shut-off valve (18) are opened, and the fifth shut-off valve (19) is closed. After passing through the first shut-off valve (15), the carbon dioxide sequentially enters the first-stage compressor (2), the first inter-stage heat exchanger (3), the second-stage compressor (4), the second inter-stage heat exchanger (5), the third-stage compressor (6), and the third inter-stage heat exchanger (7). After being condensed in the liquefier (8), the carbon dioxide is sent to the liquid carbon dioxide storage tank (9) for storage.

3. The method for operating a compressed carbon dioxide energy storage power station system in cold and severe cold regions according to claim 1, characterized in that: In S13, the low-temperature heat medium water circulation pump is turned on, and the low-temperature heat medium water is respectively sent to the first inter-stage heat exchanger (3), the second inter-stage heat exchanger (5), and the third inter-stage heat exchanger (7) through the low-temperature heat medium water circulation pump, and heat is exchanged with the exhaust gas of each stage of the compressor in the heat exchanger. After absorbing heat and rising in temperature, the low-temperature heat medium water is sent to the high-temperature heat medium water tank (11) for storage.

4. The method for operating a compressed carbon dioxide energy storage power station system in cold and severe cold regions according to claim 1, characterized in that: In S14, the high-temperature chilled water device adopts a closed cold water closed cycle, opens the sixth shut-off valve (20), replenishes water to the closed cold water expansion tank (13), and then enters the compressed carbon dioxide energy storage power station system. The closed cold water expansion tank (13) is set to absorb the volume expansion caused by temperature changes, and uses the closed cooling tower (12) to generate T g The high temperature chilled water at the temperature is sent to the liquefier (8) to condense the carbon dioxide, and then the temperature is raised to T after passing through the liquefier (8). h Return to the closed cooling tower (12); T g =T cr -T dc -T ry T h =T g +T lq -T aq Among them, T g T is the high-temperature chilled water supply temperature, in °C; h T is the high-temperature chilled water return temperature, in °C; cr is the critical temperature of carbon dioxide, in °C; T dc is the end difference of the liquefier (8), and its value range is 5-7℃; T ry T is the liquefaction redundancy temperature, ranging from 1 to 2°C; lq is the cooling end difference of the closed cooling tower (12), and its value range is 8-12℃; T aq It is the safety temperature of the closed cooling tower (12), and its value range is 1-3℃.

5. The method for operating a compressed carbon dioxide energy storage power station system in cold and severe cold regions according to claim 1, characterized in that: In S21, when releasing energy, the first shut-off valve (15), the second shut-off valve (16) and the fifth shut-off valve (19) are opened, and the third shut-off valve (17) and the fourth shut-off valve (18) are closed. Liquid carbon dioxide passes through the second shut-off valve (16) and the fifth shut-off valve (19) and then enters the third inter-stage heat exchanger (7), the third-stage compressor (6), the second inter-stage heat exchanger (5), the second-stage compressor (4), the first inter-stage heat exchanger (3), and the first-stage compressor (2) in sequence to exchange heat and perform work. After performing work, the liquid carbon dioxide is sent to the gas bin (1) for storage.

6. The method for operating a compressed carbon dioxide energy storage power station system in cold and severe cold regions according to claim 1, characterized in that: In S22, in order to make the compression energy storage and expansion energy release heat exchangers share a set of heat exchangers, the expansion ratios of each stage of the expander are distributed as follows: N6=m1N1 Among them, N4, N5, and N6 are the expansion ratios of the high-pressure cylinder, intermediate-pressure cylinder, and low-pressure cylinder of the expander; m1 is the matching coefficient between the low-pressure cylinder of the expander and the first-stage compressor (2), and its value range is 0.9-0.95; m2 is the resistance reduction coefficient of the high-pressure cylinder and the intermediate-pressure cylinder, and its value range is 0.98-0.99; P0 is the inlet pressure of the high-pressure cylinder of the expander; and P1 is the storage pressure of the gas tank (1).

7. The method for operating a compressed carbon dioxide energy storage power station system in cold and severe cold regions according to claim 1, characterized in that: In S23, the high-temperature heat medium water circulation pump is turned on, and the high-temperature heat medium water is respectively sent to the third inter-stage heat exchanger (7), the second inter-stage heat exchanger (5), and the first inter-stage heat exchanger (3) through the high-temperature heat medium water circulation pump, and exchanges heat with the exhaust gas of each stage of the compressor, and the liquid carbon dioxide is vaporized in the heat exchanger in the third inter-stage heat exchanger (7). After the high-temperature heat medium water releases heat and cools down, it is sent to the low-temperature heat medium water tank (10) for storage.

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