A compressed air energy storage system suitable for marine environments

Abstract

The utility model discloses a kind of compressed air energy storage systems suitable for marine environment, it is related to compressed air energy storage technical field.It includes including n group compressor, n group heat exchanger, n group cooler and closed cooling water system, it is sequentially connected through heat exchanger and cooler between adjacent compressor, nth group compressor is sequentially connected with gas storage through nth group heat exchanger and nth group cooler;Cooler one end is connected with seawater condenser closed water inlet through cooler closed water outlet pipeline, the other end is connected with seawater condenser closed water outlet through cooler closed water inlet pipeline.The utility model uses seawater as cooling water source, water source is stable, conducive to system stable operation;Adopt seawater as cold source, inexhaustible, and seawater temperature fluctuation is small, it can be regarded as constant temperature within 1 energy storage period, conducive to seawater condenser temperature control.

Description

Technical Field

[0001] This utility model relates to the field of compressed air energy storage technology, and more specifically, it is a compressed air energy storage system suitable for marine environments. Background Technology

[0002] Energy storage technology is one of the key technologies supporting the large-scale development of new energy sources and ensuring energy security in my country. It plays a role in many aspects, such as increasing the proportion of new energy consumption, ensuring the safe and stable operation of the power system, improving the utilization rate of power generation, transmission and distribution facilities, and promoting the integration of multiple networks. At the same time, energy storage technology is one of the key technologies for transforming randomly fluctuating energy into energy-friendly energy. The application of energy storage technology can break the bottleneck of the original power system's requirement for real-time balance in power generation, transmission, transformation, distribution and consumption.

[0003] my country's eastern coastal areas are economically developed with large electricity loads and significant peak-to-valley differences, creating an urgent need for large-scale physical energy storage, particularly compressed air energy storage. Compressed air energy storage systems offer advantages such as large scale, rapid response, high efficiency, low cost, and environmental friendliness. They can provide energy storage services including peak shaving, frequency regulation, phase regulation, spinning reserve, and emergency response, improving the efficiency, stability, and security of the power system. The overall system mainly consists of a compressed energy storage system, an expansion power generation system, a heat exchange system, a thermal storage system, and a gas storage system. Its operation is divided into an energy storage process and an energy release process. During periods of low grid load, an air compressor converts electrical energy into air potential energy and internal energy. The high-pressure air is then cooled by a heat exchanger and stored in gas storage facilities such as salt caverns, artificial chambers, or pressure vessels. During periods of high grid load, the high-pressure air in the gas storage facility is released, heated by a heat exchanger, and used to drive an air turbine to generate electricity.

[0004] Currently, there are ideas in the field of compressed air energy storage technology, such as constructing compressed air energy storage power stations on coastlines or offshore platforms, and building gas storage facilities on the seabed to construct constant-pressure compressed air energy storage power stations. Because the gas storage pressure is constant, constant-pressure compressed air energy storage power stations do not experience sliding pressure operation in the final stage compressor and the first stage turbine, resulting in higher efficiency than conventional salt cavern gas storage, artificial chamber gas storage, or surface pressure vessel gas storage type compressed air energy storage power stations, making them worthy of widespread application. The ground-based process flow of constant-pressure compressed air energy storage power stations is not significantly different from that of traditional compressed air energy storage power stations, such as... Figure 2 As shown, the compression side adopts multi-stage compression, and heat exchangers and coolers are set between each stage compressor. The heat exchanger uses heat exchange medium to recover compression heat, and the cooler uses open water to cool high-pressure air. After the low-temperature cooling water cools the air, it becomes high-temperature cooling water and enters the cooling tower. It is then cooled to low-temperature cooling water by the ambient temperature and re-enters the cooler.

[0005] Due to the limitations of ambient temperature, the temperature of low-temperature cooling water is generally higher. The smaller the temperature difference between the two, the larger the heat exchange area of ​​the cooling tower, and the higher the cost and footprint. Usually, the cooling water temperature is taken to be 5°C higher than the ambient temperature. Similarly, in the cooler, compressed air and cooling water exchange heat, and the temperature of the cooled compressed air is generally 7°C higher than that of the low-temperature cooling water. Referring to the compressed air energy storage power stations currently under construction and completed, the average summer operating temperature is generally 28°C, so the low-temperature cooling water is generally 33°C, and the compressed air at the cooler outlet is generally 40°C.

[0006] In the compression energy storage stage, the first-stage compressor draws air from the environment. The compressed, high-temperature, high-pressure air is cooled by a heat exchanger and a cooler before entering the second-stage compressor for further compression. The compressed, high-temperature, high-pressure air is then cooled by another heat exchanger and cooler before entering the storage tank, completing the compression energy storage process. During storage, the heat of compression is recovered through the heat exchanger, and the air is further cooled to 40°C by the cooler. The cooler typically uses open-loop water as the cooling medium, which is then cooled by a cooling tower. The cooling effect of the open-loop water depends on the ambient temperature and is generally designed for summer conditions (assuming an average temperature of 28°C). In this case, the cooling water temperature after the tower is 33°C, and the high-pressure air is cooled to 40°C by the cooler. Due to the large volume of cooling water, multiple cooling towers are required to achieve the desired cooling effect, resulting in high costs and a large footprint, which limits the construction of the ground-based portion of the compressed air energy storage power station. Using seawater directly as the cooling water provides a stable cold source and eliminates the need for cooling towers; however, it also presents challenges due to the high corrosiveness of seawater, requiring upgraded cooler materials and significantly increasing material costs.

[0007] Therefore, it is necessary to develop a compressed air energy storage system suitable for marine environments that can reduce power plant investment and footprint, provide a stable cold source, and not increase the cost of cooler materials. Utility Model Content

[0008] The purpose of this utility model is to solve the problem of large footprint of cooling towers in compressed air energy storage power stations in coastal areas, the problem of cooling water source in compressed air energy storage power stations in coastal areas, and the problem of high cost of traditional coolers when seawater is used as a cooling water source due to its high corrosiveness.

[0009] To achieve the above objectives, the technical solution of this utility model is as follows: a compressed air energy storage system suitable for marine environments, characterized in that it includes n sets of compressors, n sets of heat exchangers, n sets of coolers and a closed cooling water system, adjacent compressors are connected in sequence through heat exchangers and coolers, and the nth compressor is connected to the air storage tank in sequence through the nth heat exchanger and the nth cooler, where n is an integer greater than 1; The closed-loop cooling water system includes a seawater condenser connected to seawater; one end of the condenser is connected to the closed-loop water inlet of the seawater condenser via a closed-loop water outlet pipe, and the other end is connected to the closed-loop water outlet of the seawater condenser via a closed-loop water inlet pipe.

[0010] In the above technical solution, the closed cooling water system also includes a closed water circulation pump, which is installed on the closed water outlet pipe of the cooler.

[0011] In the above technical solution, the closed cooling water system further includes an expansion tank, which is connected to the closed water outlet pipe of the cooler.

[0012] In the above technical solution, the circulating medium of the cooler is demineralized water.

[0013] Compared with the prior art, this utility model has the following advantages: 1) This utility model uses seawater as a cooling water source, which is stable and conducive to the stable operation of the system; using seawater as a cold source is inexhaustible, and the temperature of seawater fluctuates little, which can be regarded as constant temperature within one energy storage cycle, which is beneficial to the temperature control of the seawater condenser.

[0014] 2) Under summer operating conditions, the seawater temperature is lower than the air temperature. Using this utility model can further reduce the outlet air temperature of the cooler, improve the work capacity of the next stage compressor, thereby reducing compressor energy consumption and improving the overall power plant efficiency.

[0015] 3) This utility model is equipped with a seawater condenser, which is small in size, light in weight, and economical and efficient.

[0016] 4) This utility model eliminates the need for a cooling tower, reducing power plant investment and floor space. Traditional compressed air energy storage power plants use open-loop cooling water, employing cooling towers to cool the water. Cooling towers occupy a large area and generate significant noise. While the equipment itself is not expensive, the costs associated with land acquisition, civil engineering, and noise reduction are substantial. This utility model's solution replaces the traditional cooling tower, reducing power plant investment and increasing the flexibility of power plant site selection.

[0017] 5) This utility model adds a closed-loop cooling water system, using demineralized water as the circulating medium. The water quality is good, and the corrosion of the cooler material is low. The cooler can be made of conventional carbon steel, and the equipment cost is low. Cooling demineralized water with seawater has a high water-to-water heat exchange coefficient, a small heat exchange area, and a lighter equipment weight. Even if expensive corrosion-resistant materials are used, the amount used is not large, and the cost is affordable. If seawater is used as the circulating medium, it will be more corrosive to metal materials, requiring expensive corrosion-resistant materials such as titanium alloys. The cooler itself is an air-to-water heat exchanger with a large heat exchange area and a lot of materials. If all of them are made of seawater corrosion-resistant materials, the price will be too high.

[0018] 6) The closed-loop water of this utility model fills the pipeline system at low temperature. After passing through the cooler, it absorbs heat and expands, increasing in volume. Therefore, an expansion tank is set up to absorb the volume of the closed-loop water after heating and expansion, which is beneficial to the stable operation of the system. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] Figure 2 This is a schematic diagram of the existing technology.

[0021] Among them, 100-compressor, 200-heat exchanger, 300-cooler, 400-closed cooling water system, 410-seawater condenser, 421-cooler closed water outlet pipe, 422-cooler closed water inlet pipe, 430-closed water circulation pump, 440-expansion tank, 500-cooling tower. Detailed Implementation

[0022] The following detailed description, in conjunction with the accompanying drawings, illustrates the implementation of this utility model. However, these descriptions do not constitute a limitation of the present utility model and are merely illustrative. Furthermore, the advantages of this utility model will become clearer and easier to understand through this description.

[0023] like Figure 1 As shown, a compressed air energy storage system suitable for marine environments is characterized by comprising n sets of compressors 100, n sets of heat exchangers 200, n sets of coolers 300, and a closed cooling water system 400. Adjacent compressors 100 are connected sequentially through heat exchangers 200 and coolers 300, and the nth set of compressors 100 is connected to the air storage tank sequentially through the nth set of heat exchangers 200 and the nth set of coolers 300. The closed cooling water system 400 includes a seawater condenser 410, which is connected to seawater; one end of the cooler 300 is connected to the closed water inlet of the seawater condenser 410 through a cooler closed water outlet pipe 421, and the other end is connected to the closed water outlet of the seawater condenser 410 through a cooler closed water inlet pipe 422.

[0024] The closed cooling water system 400 also includes a closed water circulation pump 430, which is installed on the closed water outlet pipe 421 of the cooler.

[0025] The closed cooling water system 400 also includes an expansion tank 440, which is connected to the closed water outlet pipe 421 of the cooler.

[0026] The circulating medium in the cooler 300 is demineralized water.

[0027] The seawater condenser 410 is available in various forms, such as plate shell type, shell tube type, finned tube type, header tube type, or a combination of series and parallel connections.

[0028] In actual use, such as Figure 1 As shown, taking n=2 as an example, the operation method of this utility model is as follows: High-temperature closed-loop water (demineralized water) circulates in the closed-loop cooling water system 400 through the closed-loop water circulation pump 430. After being cooled by the seawater condenser 410, the closed-loop water enters the cooler 300 to cool the compressed air. After being heated, it returns to the inlet of the closed-loop water circulation pump 430. The closed-loop water fills the closed-loop water outlet pipe 421 and the closed-loop water inlet pipe 422 of the cooler at a low temperature. After passing through the cooler 300, it absorbs heat and expands, increasing in volume. Therefore, an expansion tank 440 is set in the closed-loop water outlet pipe 421 of the cooler to absorb the volume of the closed-loop water after being heated. Clean, low-temperature seawater is drawn from the ocean as the cooling water source for the seawater condenser 410. It exchanges heat with the high-temperature closed-loop water at the outlet of the cooler 300. After being heated, it is discharged back into the ocean. The temperature of the high-temperature seawater is controlled to avoid affecting the local ecological environment.

[0029] Considering the meteorological conditions of my country's eastern coastal areas, we can assume an average summer air temperature of 28℃ and an average seawater temperature approximately 5℃ lower than the average air temperature, i.e., 23℃. Referring to the technical solution in the background section, we also assume the low-temperature cooling water temperature is 5℃ higher than the seawater temperature, and the cooled compressed air temperature is 7℃ higher than the low-temperature cooling water temperature. Therefore, the compressed air temperature at the outlet of the cooler 300 is 35℃. Under the same conditions, because the seawater temperature is lower than the air temperature, the cooling effect on the air is better.

[0030] In summary, this utility model uses seawater as the cooling water source and adds a closed-loop cooling water system. The two work together to reduce power plant investment and land area, improve the flexibility of power plant site selection, reduce compressor energy consumption, and improve the overall power plant efficiency without increasing the cost of cooler materials.

[0031] All other unspecified parts belong to the prior art.

Claims

1. A compressed air energy storage system suitable for marine environments, characterized in that: It includes n sets of compressors (100), n sets of heat exchangers (200), n sets of coolers (300) and a closed cooling water system (400). Adjacent compressors (100) are connected in sequence through heat exchangers (200) and coolers (300). The nth compressor (100) is connected to the gas storage tank in sequence through the nth heat exchanger (200) and the nth cooler (300). The closed cooling water system (400) includes a seawater condenser (410) which is connected to seawater; one end of the condenser (300) is connected to the closed water inlet of the seawater condenser (410) through a closed water outlet pipe (421), and the other end is connected to the closed water outlet of the seawater condenser (410) through a closed water inlet pipe (422).

2. The compressed air energy storage system suitable for marine environments according to claim 1, characterized in that: The closed cooling water system (400) also includes a closed water circulation pump (430), which is installed on the closed water outlet pipe (421) of the cooler.

3. A compressed air energy storage system suitable for marine environments according to claim 2, characterized in that: The closed cooling water system (400) also includes an expansion tank (440), which is connected to the closed water outlet pipe (421) of the cooler.

4. A compressed air energy storage system suitable for marine environments according to claim 1, characterized in that: The circulating medium of the cooler (300) is demineralized water.

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