A gas-water staged isothermal compressed air energy storage system

Abstract

The present invention discloses a gas-water staged isothermal compressed air energy storage system, which includes a first-stage pressure tank, a water pool, a first-stage water pump, a first regulating valve, a first-stage annular cooler, a second regulating valve, a spherical cooler, a third regulating valve and a compressor; the upper side of the first-stage pressure tank is sleeved with the first-stage annular cooler, the outlet of the water pool is divided into two paths after passing through the first-stage water pump, one path is connected to the water-side inlet of the spherical cooler through the first regulating valve, the first-stage annular cooler and the second regulating valve, and the other path is connected to the water inlet at the bottom of the first-stage pressure tank through the third regulating valve, the outlet of the compressor is connected to the gas inlet at the top of the first-stage pressure tank, and this system can solve the problems of large energy consumption, low efficiency, complex equipment system and high investment cost in the compression stage of compressed air energy storage.

Description

Technical Field

[0001] The present invention belongs to the field of physical energy storage, and relates to a gas-water staged isothermal compressed air energy storage system. Background Art

[0002] As the proportion of new energy in the power system is increasing, many problems such as "substantially fluctuating output of new energy, extremely difficult power balance and operation control, difficult accommodation when the new energy generation is large, occupying the space of conventional power sources, and prominent contradiction between accommodation and safety" will pose great challenges to the power system. Compressed air energy storage is one of the necessary options for large-capacity energy storage technologies. However, at present, the compressed air energy storage stage uses an air multi-stage compressor to take into account the inter-stage heat exchange mode. The compressor has an isentropic compression process during the compression process. Compared with isothermal compression, it has large energy consumption, low efficiency, complex equipment system and high investment cost during the compression process. These factors directly affect the efficiency of compressed air energy storage and its further popularization and application in the future. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned disadvantages of the prior art, and provide a gas-water staged isothermal compressed air energy storage system, which can solve the problems of large energy consumption, low efficiency, complex equipment system and high investment cost in the compression stage of compressed air energy storage.

[0004] To achieve the above purpose, the gas-water staged isothermal compressed air energy storage system described in the present invention includes a first-stage pressure tank, a water tank, a first-stage water pump, a first regulating valve, a first-stage annular cooler, a second regulating valve, a spherical cooler, a third regulating valve and a compressor;

[0005] The upper side of the first-stage pressure tank is sleeved with a first-stage annular cooler. The outlet of the water tank is divided into two paths after passing through the first-stage water pump. One path is connected to the water side inlet of the spherical cooler through the first regulating valve, the first-stage annular cooler and the second regulating valve, and the other path is connected to the water inlet at the bottom of the first-stage pressure tank through the third regulating valve. The outlet of the compressor is connected to the gas inlet at the top of the first-stage pressure tank.

[0006] It further includes a second-stage pressure tank, a fourth regulating valve, a first pressure buffer pipe, a second-stage water pump, a fifth regulating valve, a second-stage annular cooler, a sixth regulating valve, a seventh regulating valve and a first solenoid valve;

[0007] A second-stage annular cooler is sleeved on the upper side of the second-stage pressure tank. The water outlet at the bottom of the first-stage pressure tank is divided into two paths after passing through the fourth regulating valve, the first pressure buffer pipe and the second-stage water pump in sequence. One path is connected to the water-side inlet of the spherical cooler after passing through the fifth regulating valve, the second-stage annular cooler and the sixth regulating valve, and the other path is connected to the bottom inlet of the second-stage pressure tank after passing through the seventh regulating valve. The gas outlet at the top of the first-stage pressure tank is connected to the gas inlet at the top of the second-stage pressure tank through the first electromagnetic valve.

[0008] It further includes a third-stage pressure tank, an eighth regulating valve, a second pressure buffer pipe, a third-stage water pump, a ninth regulating valve, a third-stage annular cooler, a tenth regulating valve, an eleventh regulating valve, a second electromagnetic valve and a third electromagnetic valve;

[0009] A third-stage annular cooler is sleeved on the upper side of the third-stage pressure tank. The bottom outlet of the second-stage pressure tank is divided into two paths after passing through the eighth regulating valve, the second pressure buffer pipe and the third-stage water pump in sequence. One path is connected to the water-side inlet of the spherical cooler after passing through the ninth regulating valve, the third-stage annular cooler and the tenth regulating valve, and the other path is connected to the water inlet at the bottom of the third-stage pressure tank after passing through the eleventh regulating valve. The gas outlet at the top of the second-stage pressure tank is connected to the gas inlet at the top of the third-stage pressure tank through the second electromagnetic valve. The gas outlet at the top of the third-stage pressure tank is connected to the gas inlet of the spherical cooler through the third electromagnetic valve.

[0010] It further includes an air storage device; the gas outlet of the spherical cooler is connected to the inlet of the air storage device.

[0011] It further includes a twelfth regulating valve and a water turbine generator set. The water outlet at the bottom of the third-stage pressure tank is connected to the water-side inlet of the spherical cooler after passing through the twelfth regulating valve and the water turbine generator set in sequence.

[0012] It further includes a circulating water pump, a thirteenth regulating valve and a fourteenth regulating valve. The water-side outlet of the spherical cooler is connected to the inlet of the circulating water pump after passing through the thirteenth regulating valve and the fourteenth regulating valve, and the outlet of the circulating water pump is connected to the inlet of the water tank.

[0013] The condensate outlet on the gas side of the spherical cooler is connected to the inlet of the circulating water pump through the fifteenth regulating valve.

[0014] The middle part of the spherical cooler is the gas side, and both sides of the spherical cooler are the water sides.

[0015] The working medium in the water side of the spherical cooler and the working medium in the gas side circulate in a countercurrent manner.

[0016] The relationship between the volume V1 of the first-stage pressure tank, the volume V2 of the second-stage pressure tank and the volume V3 of the third-stage pressure tank is V2 = V1 2 / V0, V3 = V22 / V1.

[0017] The present invention has the following beneficial effects:

[0018] When the air-water staged isothermal compressed air energy storage system of the present invention is specifically operated, the water output by the first-stage water pump is injected into the first-stage pressure tank to compress the air in the first-stage pressure tank. At the same time, the water output by the first-stage water pump is sent to the first-stage annular cooler outside the first-stage pressure tank to absorb the heat generated during the air compression process, ensuring that the air temperature is always controlled within a very low change range, realizing approximate air isothermal compression, that is, realizing the process of almost constant air temperature and increasing pressure, and solving the problems of large energy consumption, low efficiency, complex equipment system and high investment cost in the compression stage of compressed air energy storage.

[0019] Furthermore, the present invention further includes a second-stage pressure tank and a third-stage pressure tank, and the air is compressed step by step through the first-stage pressure tank, the second-stage pressure tank and the third-stage pressure tank.

[0020] Furthermore, the present invention arranges a pressure buffer pipe at the inlet of the water pump. On the one hand, it can avoid the pressurized water at the outlet of the pressure tank from impacting the water pump, and can realize the function of approximate pressure stability at the inlet of the water pump, realizing the efficient and stable operation of the water pump. On the other hand, the water pump makes full use of the residual pressure on the water side of the previous stage to realize the efficient operation of the water pump.

[0021] Furthermore, by arranging a water turbine generator set, the potential energy of the high-pressure water after tail compression and the gravitational potential energy of the water are fully utilized for power generation, improving the energy utilization efficiency and energy storage efficiency of the system.

[0022] Furthermore, the present invention is provided with a spherical cooler. On the one hand, it can make full use of the cooling water in the system to further cool the air and improve the energy storage density. On the other hand, since the air will inevitably carry a large amount of saturated water after being compressed by high-pressure water at multiple levels, through cooling, the precipitation of saturated water in the high-pressure air can be realized, realizing the air drying function. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of the present invention;

[0024] Figure 2 is a schematic diagram of the spherical cooler 29.

[0025] Among them, 1 is a compressor, 2 is a first-stage pressure tank, 3 is a water tank, 4 is a first-stage water pump, 5 is a first-stage annular cooler, 6 is a third regulating valve, 7 is a first regulating valve, 8 is a fourth regulating valve, 91 is a first pressure buffer pipe, 92 is a second pressure buffer pipe, 10 is a first solenoid valve, 11 is a second regulating valve, 12 is a second-stage pressure tank, 13 is a second-stage annular cooler, 14 is a second-stage water pump, 15 is a fifth regulating valve, 16 is a seventh regulating valve, 17 is an eighth regulating valve, 18 is a second solenoid valve, 19 is a sixth regulating valve, 20 is a third-stage pressure tank, 21 is a third-stage annular cooler, 22 is a third-stage water pump, 23 is an eleventh regulating valve, 24 is a ninth regulating valve, 25 is a twelfth regulating valve, 26 is a third solenoid valve, 27 is a tenth regulating valve, 28 is a water turbine generator set, 29 is a spherical cooler, 30 is an air storage device, 31 is a circulating water pump, 32 is a thirteenth regulating valve, 33 is a fifteenth regulating valve, 34 is a fourteenth regulating valve 34. Detailed implementation manners

[0026] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present invention disclosure. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessarily confusing the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0027] The structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are only exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0028] Refer to Figure 1 and Figure 2, the air-water staged isothermal compressed air energy storage system of the present invention includes a compressor 1, a first-stage pressure tank 2, a water tank 3, a first-stage water pump 4, a first-stage annular cooler 5, a third regulating valve 6, a first regulating valve 7, a fourth regulating valve 8, a first pressure buffer pipe 91, a second pressure buffer pipe 92, a first solenoid valve 10, a second regulating valve 11, a second-stage pressure tank 12, a second-stage annular cooler 13, a second-stage water pump 14, a fifth regulating valve 15, a seventh regulating valve 16, an eighth regulating valve 17, a second solenoid valve 18, a sixth regulating valve 19, a third-stage pressure tank 20, a third-stage annular cooler 21, a third-stage water pump 22, an eleventh regulating valve 23, a ninth regulating valve 24, a twelfth regulating valve 25, a third solenoid valve 26, a tenth regulating valve 27, a water turbine generator set 28, a spherical cooler 29, an air storage device 30, a circulating water pump 31, a thirteenth regulating valve 32, a fifteenth regulating valve 33 and a fourteenth regulating valve 34;

[0029] The upper side of the first-stage pressure tank 2 is sleeved with a first-stage annular cooler 5, the upper side of the second-stage pressure tank 12 is sleeved with a second-stage annular cooler 13, and the upper side of the third-stage pressure tank 20 is sleeved with a third-stage annular cooler 21; the outlet of the water tank 3 is divided into two paths after passing through the first-stage water pump 4. One path is connected to the water-side inlet of the spherical cooler 29 through the first regulating valve 7, the first-stage annular cooler 5 and the second regulating valve 11, and the other path is connected to the water inlet at the bottom of the first-stage pressure tank 2 through the third regulating valve 6. The water outlet at the bottom of the first-stage pressure tank 2 is divided into two paths after passing through the fourth regulating valve 8, the first pressure buffer pipe 91 and the second-stage water pump 14. One path is connected to the water-side inlet of the spherical cooler 29 after passing through the fifth regulating valve 15, the second-stage annular cooler 13 and the sixth regulating valve 19, and the other path is connected to the bottom inlet of the second-stage pressure tank 12 through the seventh regulating valve 16. The bottom outlet of the second-stage pressure tank 12 is divided into two paths after passing through the eighth regulating valve 17, the second pressure buffer pipe 92 and the third-stage water pump 22. One path is connected to the water-side inlet of the spherical cooler 29 after passing through the ninth regulating valve 24, the third-stage annular cooler 21 and the tenth regulating valve 27 in sequence, and the other path is connected to the water inlet at the bottom of the third-stage pressure tank 20 through the eleventh regulating valve 23. The water outlet at the bottom of the third-stage pressure tank 20 is connected to the water-side inlet of the spherical cooler 29 through the twelfth regulating valve 25 and the water turbine generator set 28 in sequence. The water-side outlet of the spherical cooler 29 is connected to the inlet of the circulating water pump 31 through the thirteenth regulating valve 32 and the fourteenth regulating valve 34, and the outlet of the circulating water pump 31 is connected to the inlet of the water tank 3.

[0030] The outlet of the compressor 1 is communicated with the gas inlet at the top of the first-stage pressure tank 2. The gas outlet at the top of the first-stage pressure tank 2 is communicated with the gas inlet at the top of the second-stage pressure tank 12 through the first electromagnetic valve 10. The gas outlet at the top of the second-stage pressure tank 12 is communicated with the gas inlet at the top of the third-stage pressure tank 20 through the second electromagnetic valve 18. The gas outlet at the top of the third-stage pressure tank 20 is communicated with the gas inlet of the spherical cooler 29 through the third electromagnetic valve 26. The gas outlet of the spherical cooler 29 is communicated with the inlet of the air storage device 30.

[0031] It should be noted that with reference to Figure 2 , the middle part of the spherical cooler 29 is the gas side, and both sides of the spherical cooler 29 are the water side. Among them, the working medium in the water side and the working medium in the gas side circulate in a countercurrent manner to improve the heat exchange effect. The condensate outlet of the gas side of the spherical cooler 29 is communicated with the inlet of the circulating water pump 31 through the fifteenth regulating valve 33.

[0032] The volumes of the first-stage pressure tank 2, the second-stage pressure tank 12, and the third-stage pressure tank 20 decrease in sequence. Preferably, the relationship between the volume V1 of the first-stage pressure tank 2, the volume V2 of the second-stage pressure tank 12, and the volume V3 of the third-stage pressure tank 20 is V2 = V1 2 / V0, V3 = V2 2 / V1.

[0033] The specific working process of the present invention is as follows:

[0034] When energy storage is required on the power supply side, the compressor 1 is started to raise the normal temperature and pressure air to 1.5 - 2 MPa and 35 - 40 °C. After the first-stage pressure tank 2 is filled, the compressor 1 is turned off. Subsequently, the first-stage water pump 4 is started, and the water in the water tank 3 is raised to 4 - 4.5 MPa and 15 - 20 °C by the first-stage water pump 4 and then divided into two paths. One path is sent into the first-stage pressure tank 2. By adjusting the opening degrees of the third regulating valve 6 and the first regulating valve 7, it is ensured that the air temperature in the first-stage pressure tank 2 during the compression process is 30 - 32 °C. As the water volume in the first-stage pressure tank 2 continuously increases, the air is compressed to 3.8 - 4 MPa and 30 - 32 °C. Then, the first solenoid valve 10 is opened, and the air at 3.8 - 4 MPa and 30 - 32 °C is forced into the second-stage pressure tank 12 by the water in the first-stage pressure tank 2. Since the volume of the second-stage pressure tank 12 becomes smaller, it is ensured that the air pressure and temperature in the second-stage pressure tank 12 remain almost unchanged. All the air after the first-stage compression is sent into the second-stage pressure tank 12. At this time, the first-stage pressure tank 2 is in a state of being filled with water. Then, the fourth regulating valve 8 is opened, and the water in the first-stage pressure tank 2 is sent into the second-stage water pump 14 by relying on its own pressure and gravity. The first pressure buffer pipe 91 is relied on to ensure the stable pressure of the water at the inlet of the second-stage water pump 14. After being boosted by the second-stage water pump 14, the parameters of the water at the outlet of the second-stage water pump 14 are 8 - 8.5 MPa and 20 - 22 °C. The water output by the second-stage water pump 14 is divided into two paths. One path is sent into the compressed air in the second-stage pressure tank 12, and the other path is sent into the second-stage annular cooler 13 to cool the air. By adjusting the opening degrees of the fifth regulating valve 15 and the seventh regulating valve 16, it is ensured that the air temperature in the second-stage pressure tank 12 during the compression process is 35 - 38 °C.As the water volume in the second-stage pressure tank 12 continuously increases, the air is compressed to 7.8 - 8 MPa and 35 - 38 °C. Then, the second solenoid valve 18 is opened, and the air at 7.8 - 8 MPa and 35 - 38 °C is forced into the third-stage pressure tank 20 by the water in the second-stage pressure tank 12. Since the volume of the third-stage pressure tank 20 is further reduced, it can ensure that the air pressure and temperature in the third-stage pressure tank 20 remain almost unchanged. All the air after the second-stage compression is sent into the third-stage pressure tank 20. At this time, the second-stage pressure tank 12 is in a state full of water. Then, the eighth regulating valve 17 is opened, and the water in the second-stage pressure tank 12 is sent into the third-stage water pump 22 by its own pressure and gravity. The second pressure buffer pipe 92 is relied on to ensure the stable pressure of the water at the inlet of the third-stage water pump 22. After being boosted by the third-stage water pump 22, the parameters at the outlet of the third-stage water pump 22 are 16 - 16.5 MPa and 22 - 24 °C. The water output by the third-stage water pump 22 is divided into two paths. One path is sent into the compressed air in the third-stage pressure tank 20, and the other path is sent into the second-stage annular cooler 13 to cool the air in the third-stage pressure tank 20. By adjusting the opening degrees of the eleventh regulating valve 23 and the ninth regulating valve 24, the air temperature in the third-stage pressure tank 20 during the compression process is ensured to be 38 - 40 °C. As the water volume in the third-stage pressure tank 20 continuously increases, the air is compressed to 15.8 - 16 MPa and 38 - 40 °C. Then, the third solenoid valve is opened, and the air at 15.8 - 16 MPa and 38 - 40 °C is forced into the spherical cooler 29 by the water in the third-stage pressure tank 20 to be cooled and condensed to air at 16 MPa and 30 °C, which is sent into the air storage device 30. The water in the third-stage pressure tank 20 does work and generates electricity through the water turbine generator set 28 by its own pressure and gravitational potential energy. The water output by the water turbine generator set 28 is collected in the water side of the spherical cooler 29, and then after converging with the water output from the third-stage pressure tank 20, it exchanges heat with the air in the gas side of the spherical cooler 29. By adjusting the ratio of the two, the water temperature is controlled to 22 - 25 °C, ensuring that the air parameters stored in the air storage device 30 are 15.8 - 16 MPa and 30 - 32 °C. Similarly, after repeating the above process hundreds of times, a large amount of air is converted to be stored at 15.8 - 16 MPa and 30 - 32 °C, and the isothermal compression energy storage process ends. Since the air temperature hardly changes during this process, this process can be approximately considered as an isothermal compression process.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A gas-water staged isothermal compressed air energy storage system, characterized in that, It includes a first-stage pressure tank (2), a water tank (3), a first-stage water pump (4), a first regulating valve (7), a first-stage annular cooler (5), a second regulating valve (11), a spherical cooler (29), a third regulating valve (6) and a compressor (1); The upper side of the first-stage pressure tank (2) is sleeved with the first-stage annular cooler (5). The outlet of the water tank (3) is divided into two paths after passing through the first-stage water pump (4). One path is connected to the water-side inlet of the spherical cooler (29) through the first regulating valve (7), the first-stage annular cooler (5) and the second regulating valve (11), and the other path is connected to the water inlet at the bottom of the first-stage pressure tank (2) through the third regulating valve (6). The outlet of the compressor (1) is connected to the gas inlet at the top of the first-stage pressure tank (2); It further includes a second-stage pressure tank (12), a fourth regulating valve (8), a first pressure buffer pipe (91), a second-stage water pump (14), a fifth regulating valve (15), a second-stage annular cooler (13), a sixth regulating valve (19), a seventh regulating valve (16) and a first solenoid valve (10); The upper side of the second-stage pressure tank (12) is sleeved with the second-stage annular cooler (13). The water outlet at the bottom of the first-stage pressure tank (2) is divided into two paths after passing through the fourth regulating valve (8), the first pressure buffer pipe (91) and the second-stage water pump (14). One path is connected to the water-side inlet of the spherical cooler (29) after passing through the fifth regulating valve (15), the second-stage annular cooler (13) and the sixth regulating valve (19), and the other path is connected to the bottom inlet of the second-stage pressure tank (12) through the seventh regulating valve (16). The gas outlet at the top of the first-stage pressure tank (2) is connected to the gas inlet at the top of the second-stage pressure tank (12) through the first solenoid valve (10); It further includes a third-stage pressure tank (20), an eighth regulating valve (17), a second pressure buffer pipe (92), a third-stage water pump (22), a ninth regulating valve (24), a third-stage annular cooler (21), a tenth regulating valve (27), an eleventh regulating valve (23), a second solenoid valve (18) and a third solenoid valve (26); The upper side of the third-stage pressure tank (20) is sleeved with the third-stage annular cooler (21). The bottom outlet of the second-stage pressure tank (12) is divided into two paths after passing through the eighth regulating valve (17), the second pressure buffer pipe (92) and the third-stage water pump (22). One path is connected to the water-side inlet of the spherical cooler (29) after passing through the ninth regulating valve (24), the third-stage annular cooler (21) and the tenth regulating valve (27), and the other path is connected to the water inlet at the bottom of the third-stage pressure tank (20) through the eleventh regulating valve (23). The gas outlet at the top of the second-stage pressure tank (12) is connected to the gas inlet at the top of the third-stage pressure tank (20) through the second solenoid valve (18), and the gas outlet at the top of the third-stage pressure tank (20) is connected to the gas inlet of the spherical cooler (29) through the third solenoid valve (26).

2. The isothermal compressed air energy storage system with gas-water grading according to claim 1, wherein It further includes an air storage device (30); the gas outlet of the spherical cooler (29) is connected to the inlet of the air storage device (30).

3. The isothermal compressed air energy storage system with gas-water grading according to claim 1, characterized in that, It further includes a twelfth regulating valve (25) and a hydro-generating unit (28). The water outlet at the bottom of the third-stage pressure tank (20) is successively connected to the water-side inlet of the spherical cooler (29) via the twelfth regulating valve (25) and the hydro-generating unit (28).

4. The air-water graded isothermal compressed air energy storage system according to claim 1, wherein, It further includes a circulating water pump (31), a thirteenth regulating valve (32) and a fourteenth regulating valve (34). The water-side outlet of the spherical cooler (29) is connected to the inlet of the circulating water pump (31) via the thirteenth regulating valve (32) and the fourteenth regulating valve (34), and the outlet of the circulating water pump (31) is connected to the inlet of the water tank (3).

5. The isothermal compressed air energy storage system with air-water grading according to claim 4, characterized in that, The condensate outlet on the gas side of the spherical cooler (29) is connected to the inlet of the circulating water pump (31) via a fifteenth regulating valve (33).

6. The isothermal compressed air energy storage system with air-water grading according to claim 1, characterized in that, The volume V1 of the first-stage pressure tank (2), the volume V2 of the second-stage pressure tank (12), and the volume V3 of the third-stage pressure tank (20) are related as V2 = V1 2 / V0, V3 = V2 2 / V1.

7. The isothermal compressed air energy storage system with gas-water grading according to claim 1, characterized in that, The middle part of the spherical cooler (29) is the gas side, and both sides of the spherical cooler (29) are the water sides.

8. The isothermal compressed air energy storage system with gas-water classification and grading according to claim 1, characterized in that, The working medium in the water side and the working medium in the gas side of the spherical cooler (29) circulate in a countercurrent manner.

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