A compressed air energy storage power plant cold start system

Abstract

The utility model relates to the technical field of energy storage, and specifically discloses a compressed air energy storage power station cold start system, which comprises a gas storage, a compressor unit, a gas-water cooler, a gas-water heater, a high-temperature water tank and a low-temperature water tank, the gas outlet end of the compressor unit is connected with the gas inlet end of the gas-water cooler, the gas outlet end of the gas-water cooler is connected with the gas inlet end of the gas storage through a second valve, the gas outlet end of the gas storage is connected with the gas inlet end of the gas-water heater through a ninth valve, the water outlet end of the gas-water cooler is connected with the high-temperature water tank through a first valve, the water outlet end of the high-temperature water tank is connected with the water inlet end of a high-temperature pump, the water outlet end of the high-temperature pump is connected with the water inlet end of the gas-water heater through a sixth valve, and the water outlet end of the gas-water heater is connected with the low-temperature water tank through an eighth valve. The utility model has the advantages that the method of gradually increasing the temperature of high-temperature water and improving the water inflow of the gas-water heater through the mixed flow box can quickly and uniformly increase the metal temperature of the heater and improve the energy utilization rate of the system.

Description

Technical Field

[0001] This utility model relates to the field of energy storage technology, and in particular to a cold start system for a compressed air energy storage power station. Background Technology

[0002] Compressed air energy storage, as a novel energy storage system, requires frequent start-ups and shutdowns on both the compression and turbine sides due to its energy storage and discharge characteristics, in order to achieve energy storage and release. During the energy release phase, the turbine unit's start-up and shutdown can be divided into hot start-up and cold start-up. The unit typically operates under a hot start-up during normal system operation. When maintenance or repairs cause the equipment's metal temperature to drop to room temperature, the system must execute a cold start-up procedure.

[0003] During cold starts, to prevent uneven heating of the equipment's metal from causing excessive localized expansion and resulting in deformation or equipment damage, equipment manufacturers typically provide corresponding cold start specifications to avoid such risks. Cold starts of the turbine-side heater usually involve injecting high-temperature water at a small flow rate to control the heat exchanger's temperature rise rate, raising the overall heater temperature from ambient to the rated temperature, thus completing the cold start (i.e., heat exchanger preheating). High-pressure air is only allowed to pass through the heater and drive the turbine to execute the cold start procedure for the turbine expander unit when the overall heater temperature reaches the minimum inlet air temperature required for a cold start. This cold start procedure presents challenges such as lengthy heater preheating time, difficulty in temperature rise control, and high energy consumption of related auxiliary equipment. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a cold start system for compressed air energy storage power stations.

[0005] The purpose of this utility model is achieved through the following technical solution: a cold start system for a compressed air energy storage power station, comprising an air storage tank, a compressor unit, an air-water cooler, an air-water heater, a high-temperature water tank and a low-temperature water tank, wherein the air outlet of the compressor unit is connected to the air inlet of the air-water cooler, the air outlet of the air-water cooler is connected to the air inlet of the air storage tank through a second valve, the air outlet of the air storage tank is connected to the air inlet of the air-water heater through a ninth valve, and the air outlet of the air-water heater is connected to a turbine unit;

[0006] The outlet of the air-water cooler is connected to a high-temperature water tank via a first valve. The outlet of the high-temperature water tank is connected to the inlet of a high-temperature pump. The outlet of the high-temperature pump is connected to the inlet of an air-water heater via a sixth valve. The outlet of the air-water heater is connected to a low-temperature water tank via an eighth valve. The outlet of the low-temperature water tank is connected to the inlet of a low-temperature pump. The outlet of the low-temperature pump is connected to the inlet of the air-water cooler via a third valve.

[0007] Specifically, it also includes a mixing tank, the outlet of the high-temperature pump is connected to the high-temperature inlet of the mixing tank through a fifth valve, the outlet of the mixing tank is connected to the inlet of the air-water heater through a seventh valve; and the outlet of the low-temperature pump is connected to the low-temperature inlet of the mixing tank through a fourth valve.

[0008] Specifically, it also includes a return water tank. The drain outlet of the mixing box is connected to the inlet of the return water tank through an eleventh valve. The drain outlet of the air-water heater is connected to the inlet of the return water tank through a tenth valve. The outlet of the return water tank is connected to the inlet of the return water pump. The outlet of the return water pump is connected to the inlet of the low-temperature water tank through a thirteenth valve. The outlet of the return water pump is connected to the inlet of the high-temperature water tank through a twelfth valve.

[0009] Specifically, the volume of the mixing tank is 0.3 to 0.5% of the volume of the high-temperature water tank.

[0010] Specifically, the mixing chamber is cylindrical, with its high-temperature inlet and low-temperature inlet located at the upper end, its outlet located at the lower end, and its drain outlet located at the bottom. The high-temperature inlet and low-temperature inlet are positioned opposite each other, and their water inlet directions are tangential to the mixing chamber.

[0011] Specifically, a cross-shaped baffle is provided at the bottom of the mixing chamber.

[0012] This utility model has the following advantages:

[0013] This invention utilizes a method to gradually increase the temperature of high-temperature water and the inlet flow rate of the gas-water heater through a mixing chamber. This method ensures that the heater is under low thermal stress during the preheating process while rapidly and uniformly raising the metal temperature of the heater. As a result, it achieves the goals of shortening the cold start time of the turbine-side heater, reducing the energy consumption of auxiliary equipment in the system, and improving the energy utilization rate of the system. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the cold start system structure of this utility model;

[0015] Figure 2 This is a front view structural diagram of the mixing box of this utility model;

[0016] Figure 3 This is a top view of the mixing chamber structure of this utility model;

[0017] In the diagram: 1-Compressor unit, 2-Second valve, 3-Gas storage tank, 4-Thirteenth valve, 5-Return water pump, 6-Eighth valve, 7-Ninth valve, 8-Turbine unit, 9-Gas-water heater, 10-Tenth valve, 11-Seventh valve, 12-Mixing box, 13-Sixth valve, 14-Fifth valve, 15-High temperature pump, 16-High temperature water tank, 17-First valve, 18-Gas-water cooler, 19-Third valve, 20-Return water tank, 21-Twelfth valve, 22-Fourth valve, 23-Low temperature pump, 24-Low temperature water tank, 25-Eleventh valve, 26-High temperature inlet, 27-Low temperature inlet, 28-Drain outlet, 29-Outlet, 30-Cross-shaped baffle. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present utility model and are not intended to limit the present utility model; that is, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The components of the embodiments of the present utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0021] The present invention will be further described below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0022] like Figures 1 to 3As shown, a cold start system for a compressed air energy storage power station includes an air storage tank 3, a compressor unit 1, an air-water cooler 18, an air-water heater 9, a high-temperature water tank 16, and a low-temperature water tank 24. The air outlet of the compressor unit 1 is connected to the air inlet of the air-water cooler 18. The air outlet of the air-water cooler 18 is connected to the air inlet of the air storage tank 3 through a second valve 2. The air outlet of the air storage tank 3 is connected to the air inlet of the air-water heater 9 through a ninth valve 7. The air outlet of the air-water heater 9 is connected to a turbine unit 8.

[0023] The outlet of the air-water cooler 18 is connected to the high-temperature water tank 16 via a first valve 17. The outlet of the high-temperature water tank 16 is connected to the inlet of the high-temperature pump 15. The outlet of the high-temperature pump 15 is connected to the inlet of the air-water heater 9 via a sixth valve 13. The outlet of the air-water heater 9 is connected to the low-temperature water tank 24 via an eighth valve 6. The outlet of the low-temperature water tank 24 is connected to the inlet of the low-temperature pump 23. The outlet of the low-temperature pump 23 is connected to the inlet of the air-water cooler 18 via a third valve 19. A mixing chamber 12 is also included. The outlet of the high-temperature pump 15 is connected to the high-temperature inlet 26 of the mixing chamber 12 via a fifth valve 14. The outlet 29 of the mixing chamber 12 is connected to the inlet of the air-water heater 9 via a seventh valve 11. The outlet of the low-temperature pump 23 is connected to the low-temperature inlet 27 of the mixing chamber 12 via a fourth valve 22. It also includes a return water tank 20. The drain outlet 28 of the mixing box 12 is connected to the inlet of the return water tank 20 through the eleventh valve 25. The drain outlet of the gas-water heater 9 is connected to the inlet of the return water tank 20 through the tenth valve 10. The outlet of the return water tank 20 is connected to the inlet of the return water pump 5. The outlet of the return water pump 5 is connected to the inlet of the low-temperature water tank 24 through the thirteenth valve 4. The outlet of the return water pump 5 is connected to the inlet of the high-temperature water tank 16 through the twelfth valve 21. The compressed air energy storage system energy storage cycle is divided into a charging stage, a high-pressure gas storage stage, an energy release stage, and a low-pressure gas storage stage. The charging stage and the energy release stage need to determine whether to execute a cold start process or a warm / hot start process based on the metal temperature of the equipment. Among them, for the cold start of the energy release stage, the gas-water heater needs to be preheated before the cold start process of the turbine unit can be executed.

[0024] The system cold start procedure is as follows:

[0025] During system shutdown, when the water temperature inside the gas-water heater 9 drops to a low temperature, i.e., close to the temperature of the low-temperature water tank 24, the tenth valve 10 of the gas-water heater 9 is opened, and the water return tank 20 is located at the low position of the system, which can ensure that the gas-water heater 9 can empty the liquid inside the equipment by gravity. When the liquid level in the water return tank 20 reaches the starting water level of the water return pump 5, the water return pump 5 pumps the low-temperature water into the low-temperature water tank 24.

[0026] When the system completes maintenance or restarts, during the system charging phase, the compression side performs the conventional cold start process and prepares high-temperature water. At the end of the charging phase, the low-temperature water tank 24 needs to reserve a certain amount of low-temperature water for the cold start of the energy release phase.

[0027] After confirming that the auxiliary equipment of the compressed air energy storage system is in good working order, start the preheating program for the air-water heater. The specific preheating program is as follows:

[0028] Close the first valve 17, the second valve 2, the third valve 19, the sixth valve 13, the ninth valve 7, and the tenth valve 10, open the fourth valve 22, the fifth valve 14, the seventh valve 11, and the eighth valve 6, and start the high-temperature pump 15 and the low-temperature pump 23 to fully mix the high-temperature water and the low-temperature water in the mixing tank 12, thereby reducing the inlet water temperature entering the air-water heater 9.

[0029] When the global temperature of the gas-water heater 9 reaches the design preheating temperature, the cryogenic pump 23 is turned off, and the fourth valve 22 is closed. The sixth valve 13 is opened, and after the sixth valve 13 is fully opened, the fifth valve 14 and the seventh valve 11 are closed.

[0030] The preheating process of the gas-water heater 9 has ended.

[0031] After the preheating process is completed, open the eleventh valve 25 and the twelfth valve 21 of the mixing tank 12, start the drain pump 5, and drain the liquid from the mixing tank 12.

[0032] After the heater preheating process is completed, the ninth valve 7 is opened to allow air to enter the gas-water heater 9. By controlling the opening of the eighth valve 6, the air temperature output by the gas-water heater 9 is adjusted to ensure that the air inlet temperature of the turbine unit 8 meets the cold start requirements of the turbine unit 8.

[0033] The air-driven turbine unit 8 executes the start-up process according to the set cold start-up curve. After the start-up is completed, it enters the rated power generation condition.

[0034] Furthermore, the volume of the mixing chamber 12 is 0.3~0.5% of the volume of the high-temperature water tank 16. The function of the mixing chamber is to ensure that the hot and cold fluids are fully mixed within the chamber. The design working pressure and temperature of the mixing chamber 12 are consistent with those of the high-temperature water tank. The design of the mixing chamber 12 should be able to withstand the vibration caused by fluid collisions during the mixing process, and should not cause damage to the chamber due to vibration. The volume of the mixing chamber 12 should not be too large, as an excessively large chamber will lead to excessive heat loss after cold start, affecting system efficiency. The volume of the mixing chamber 12 should also not be too small, as an excessively small chamber will easily lead to insufficient mixing of the hot and cold fluids. Therefore, the volume of the mixing chamber 12 should preferably be 0.3~0.5% of the total volume of the high-temperature water tank 16.

[0035] Furthermore, the mixing chamber 12 is cylindrical, with a high-temperature inlet 26 and a low-temperature inlet 27 located at its upper end, and an outlet 29 located at its lower end. The drain outlet 28 of the mixing chamber 12 is located at its bottom. The high-temperature inlet 26 and the low-temperature inlet 27 are positioned opposite each other, with their inlet directions tangential to the mixing chamber 12 and opposite to each other. A cross-shaped baffle 30 is provided at the bottom of the mixing chamber 12. The drain outlet 28 is located at the lowest point of the mixing chamber 12 to ensure effective drainage of the liquid. The diameter of the outlet 29 of the mixing chamber 12 is the same as the diameter of the pipe of the sixth valve 13.

[0036] In this embodiment, the mixing tank 12 is a cylindrical tank. The high-temperature inlet 26 and the low-temperature inlet 27 are closely attached to the tank wall and are arranged opposite to each other. When the fluid is injected into the tank, the liquid will rotate and flow inside the tank due to the angle of the pipes. At the same time, a cross-shaped baffle 30 is arranged at the bottom of the tank to ensure that the fluid is fully mixed.

[0037] The above description is merely a preferred embodiment of this utility model and does not constitute any limitation on this utility model. Any person skilled in the art can make many possible variations and modifications to the technical solution of this utility model, or modify it into equivalent embodiments, without departing from the scope of the technical solution of this utility model. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technology of this utility model without departing from the scope of the technical solution of this utility model shall fall within the protection scope of this technical solution.

Claims

1. A cold start system for a compressed air energy storage power station, characterized in that: The system includes a gas storage tank (3), a compressor unit (1), a gas-water cooler (18), a gas-water heater (9), a high-temperature water tank (16), and a low-temperature water tank (24). The outlet of the compressor unit (1) is connected to the inlet of the gas-water cooler (18). The outlet of the gas-water cooler (18) is connected to the inlet of the gas storage tank (3) through a second valve (2). The outlet of the gas storage tank (3) is connected to the inlet of the gas-water heater (9) through a ninth valve (7). The outlet of the gas-water heater (9) is connected to a turbine unit (8). The outlet of the air-water cooler (18) is connected to the high-temperature water tank (16) through the first valve (17). The outlet of the high-temperature water tank (16) is connected to the inlet of the high-temperature pump (15). The outlet of the high-temperature pump (15) is connected to the inlet of the air-water heater (9) through the sixth valve (13). The outlet of the air-water heater (9) is connected to the low-temperature water tank (24) through the eighth valve (6). The outlet of the low-temperature water tank (24) is connected to the inlet of the low-temperature pump (23). The outlet of the low-temperature pump (23) is connected to the inlet of the air-water cooler (18) through the third valve (19).

2. The cold start system for a compressed air energy storage power station according to claim 1, characterized in that: It also includes a mixing tank (12), the outlet of the high temperature pump (15) is connected to the high temperature inlet (26) of the mixing tank (12) through the fifth valve (14), the outlet (29) of the mixing tank (12) is connected to the inlet of the gas-water heater (9) through the seventh valve (11); the outlet of the low temperature pump (23) is connected to the low temperature inlet (27) of the mixing tank (12) through the fourth valve (22).

3. The cold start system for a compressed air energy storage power station according to claim 2, characterized in that: It also includes a return water tank (20), the drain outlet (28) of the mixing box (12) is connected to the inlet of the return water tank (20) through the eleventh valve (25), the drain outlet of the air-water heater (9) is connected to the inlet of the return water tank (20) through the tenth valve (10), the outlet of the return water tank (20) is connected to the inlet of the return water pump (5), the outlet of the return water pump (5) is connected to the inlet of the low temperature water tank (24) through the thirteenth valve (4), and the outlet of the return water pump (5) is connected to the inlet of the high temperature water tank (16) through the twelfth valve (21).

4. The cold start system for a compressed air energy storage power station according to claim 2, characterized in that: The volume of the mixing tank (12) is 0.3 to 0.5% of the volume of the high-temperature water tank (16).

5. A cold start system for a compressed air energy storage power station according to claim 2, characterized in that: The mixing chamber (12) is cylindrical, with its high-temperature inlet (26) and low-temperature inlet (27) located at the upper end of the mixing chamber (12), and its outlet (29) located at the lower end of the mixing chamber (12). The drain outlet (28) of the mixing chamber (12) is located at the bottom of the mixing chamber (12). The high-temperature inlet (26) and the low-temperature inlet (27) are arranged opposite to each other, and the water inlet directions of the high-temperature inlet (26) and the low-temperature inlet (27) are tangential to the mixing chamber (12). The water inlet directions of the high-temperature inlet (26) and the low-temperature inlet (27) are opposite.

6. The cold start system for a compressed air energy storage power station according to claim 2, characterized in that: The bottom of the mixing box (12) is provided with a cross-shaped baffle (30).

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