Compressed air-fused salt combined energy storage photo-thermal-fuel backup complementary power generation system

Abstract

A compressed air-fused salt combined energy storage photo-thermal-fuel backup complementary power generation system mainly comprises a compressed air energy storage system, a cooling water system, a photo-thermal energy storage system, a combustion energy storage backup system and an energy storage power generation system. The compressed air energy storage system compresses air through a multi-stage isothermal compressor and stores the compressed air in a compressed air storage tank. The cooling water system is used for cooling heat generated by the compressor. The photo-thermal energy storage system utilizes a photo-thermal tower and a heliostat field to convert solar energy into fused salt heat energy. When photo-thermal energy storage is insufficient, the combustion energy storage backup system can heat fused salt through the combustion furnace to supplement energy. The energy storage power generation system heats compressed air through heat energy of high-temperature fused salt, a multi-stage isothermal expansion machine is driven to generate power, and meanwhile a heat recovery device recovers heat energy and is used for preheating the compressed air. According to the system, efficient and stable energy supply is achieved through combined energy storage and complementary power generation, and a new thought and a technical path are provided for development and utilization of renewable energy sources.

Description

Technical Field

[0001] The utility model belongs to the field of energy storage technology, and in particular relates to a compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system. Background Art

[0002] As the global energy mix shifts toward clean, renewable energy, the large-scale deployment of renewable energy sources such as solar thermal energy has become an inevitable trend. However, the inherent instability and uncertainty of these renewable energy sources compromises the continuity and stability of energy supply, posing challenges to the safe operation of the power grid. Although our institution has successfully developed a hydraulically balanced isothermal cycle energy storage power generation system (Application No. 2024108305209) and a coal-fired energy storage power generation system (Application No. 2024214667166), which address the instability and uncertainty of renewable energy to some extent, these technologies primarily rely on electricity converted from photovoltaic and wind power for green energy utilization, neglecting the direct use of other renewable energy sources such as solar thermal energy. Furthermore, their backup energy capabilities remain limited, limited to providing stable energy support when renewable energy supply is insufficient or interrupted, and cannot achieve the same backup power supply performance as diesel generators.

[0003] To this end, this application proposes a compressed air-molten salt combined energy storage solar thermal power generation model, aiming to achieve stable direct utilization of renewable energy, further improve energy utilization efficiency, and ensure the continuity and stability of energy supply. By designing a backup energy source, it achieves a backup effect similar to that of a diesel generator. This utility model will provide strong support for the transformation of the global energy structure and promote the widespread application of renewable energy, with important practical significance and broad market prospects. Summary of the Invention

[0004] This utility model provides a power generation system with a combined compressed air and molten salt energy storage system and a complementary solar thermal and fuel backup system. This system integrates compressed air energy storage, molten salt energy storage, solar thermal power generation, and combustion power generation technologies, organically combining the energy storage and backup energy systems to form a new energy supply model. This model not only enables peak-to-valley shifting of electricity but also addresses the instability and uncertainty of renewable energy, achieving efficient energy utilization and optimized allocation.

[0005] The specific description is as follows: A compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system, including a compressed air energy storage system, a cooling water system, a solar thermal energy storage system, a combustion energy storage backup system, and an energy storage power generation system;

[0006] The compressed air energy storage system includes a multi-stage cooler, a multi-stage isothermal compressor, a compressed air storage tank, a water reservoir, a hydraulic generator, and connecting pipes therebetween; the multi-stage isothermal compressor has multiple compression stages, and the multi-stage cooler has multiple coolers; the inlet / outlet of the cooler air medium channel of the multi-stage cooler is respectively connected to the working medium outlet of the previous compression stage / the working medium inlet of the next compression stage of the multi-stage isothermal compressor;

[0007] The working medium inlet of the first compression stage of the multi-stage isothermal compressor is directly connected to the environment, and the working medium outlet of the last compression stage is connected to the inlet of the working medium channel of the compressed air storage tank; the hydraulic generator is connected between the bottom of the compressed air storage tank and the bottom end of the water reservoir;

[0008] The cooling water system includes a cooling tower, a cooling water pump, a multi-stage cooler and connecting pipes therebetween; the cooling water channels of the multi-stage cooler, the cooling water pump and the cooling tower are connected by pipes to form a cooling water circulation system;

[0009] The solar thermal energy storage system includes a high-temperature molten salt tank, a low-temperature molten salt tank, a solar thermal tower, a heliostat field, a first molten salt pump, and connecting pipes between them; the first molten salt pump is connected between the low-temperature molten salt tank and the solar thermal tower, and the high-temperature molten salt tank is directly connected to the solar thermal tower;

[0010] The combustion energy storage backup system includes a high-temperature molten salt tank, a low-temperature molten salt tank, a combustion furnace, a molten salt coil, a first molten salt pump, and connecting pipes between them; the molten salt coil is evenly arranged in the combustion furnace, one end of the molten salt coil is connected to the outlet of the first molten salt pump, the inlet of the first molten salt pump is connected to the low-temperature molten salt storage tank, and the other end of the molten salt coil is connected to the high-temperature molten salt storage tank;

[0011] The energy storage and power generation system includes a heat recovery device, a compressed air storage tank, a water reservoir, a multi-stage isothermal expander, a multi-stage countercurrent heat exchanger, a high-temperature molten salt tank, a low-temperature molten salt tank, a second molten salt pump, a pressure pump, a generator and connecting pipes therebetween; the multi-stage isothermal expander has multiple expansion stages, and the multi-stage countercurrent heat exchanger has multiple countercurrent heat exchangers corresponding one-to-one to the expansion stages of the multi-stage isothermal expander; the countercurrent heat exchanger of the multi-stage countercurrent heat exchanger is installed on the expansion working medium pipeline between every two expansion stages of the multi-stage isothermal expander or on the working medium pipeline between the heat recovery device and the first-stage isothermal expander of the multi-stage isothermal expander; the molten salt medium inlet of each stage of the countercurrent heat exchanger of the multi-stage countercurrent heat exchanger is connected to the outlet of the second molten salt pump, the inlet of the second molten salt pump is connected to the high-temperature molten salt storage tank, and the outlet of each stage of the countercurrent heat exchanger of the multi-stage countercurrent heat exchanger is connected to the low-temperature molten salt storage tank;

[0012] The compressed air storage tank is connected to the working medium channel inlet of the heat recovery device through a pipeline, and the outlet of the working medium channel of the heat recovery device is respectively connected to the working medium inlet of the first-stage countercurrent heat exchanger of the multi-stage countercurrent heat exchanger; the exhaust gas channel inlet of the heat recovery device is connected to the exhaust gas outlet of the last expansion stage of the multi-stage isothermal expander, and the exhaust gas channel outlet of the heat recovery device is connected to the environment;

[0013] The booster pump is connected between the bottom of the compressed air storage tank and the bottom end of the water reservoir.

[0014] Furthermore, it also includes a clutch connected between the multi-stage isothermal compressor and the multi-stage isothermal expander.

[0015] Furthermore, the multi-stage isothermal compressor, the multi-stage isothermal expander, and the generator are installed on the same rotating shaft, and the multi-stage isothermal expander drives the generator to generate electricity.

[0016] Furthermore, the first-stage countercurrent heat exchanger of the multi-stage countercurrent heat exchanger is installed on the working fluid pipeline between the working fluid channel of the heat recovery device and the first-stage expansion stage of the multi-stage isothermal expander; the inlets / outlets of the remaining countercurrent heat exchangers of the multi-stage countercurrent heat exchanger except the first-stage countercurrent heat exchanger are respectively connected to the working fluid outlet of the previous expansion stage / the working fluid inlet of the next expansion stage of the multi-stage isothermal expander.

[0017] Furthermore, it includes a multi-stage combustion chamber, which has multiple combustion chambers corresponding one to one to the expansion stages of the multi-stage isothermal expander; the combustion chambers of the multi-stage combustion chamber are installed on the expansion working fluid pipeline between every two expansion stages of the multi-stage isothermal expander or on the working fluid pipeline between the heat recovery device and the first-stage isothermal expander of the multi-stage isothermal expander.

[0018] Furthermore, the working fluid inlet of the first-stage combustion chamber of the multi-stage combustion chamber is connected to the outlet of the working fluid channel of the heat recovery device; the inlet / outlet of the combustion chamber other than the first-stage combustion chamber of the multi-stage combustion chamber is respectively connected to the working fluid outlet of the previous expansion stage / the working fluid inlet of the next expansion stage of the multi-stage isothermal expander.

[0019] Furthermore, the fuel in the multi-stage combustion chamber is one of coal gas, natural gas, hydrogen and liquid fuel.

[0020] Furthermore, the fuel in the combustion furnace is a mixture of one or more of coal, coal powder, biomass, coal gas, natural gas, hydrogen, and liquid fuel.

[0021] Furthermore, the heat recovery device is a countercurrent heat exchanger.

[0022] This utility model demonstrates the following four significant advantages in addressing the challenge of complementary combined power generation of renewable energy and fuel backup:

[0023] 1) Efficient Energy Utilization and Storage: Through a cleverly designed combined solar thermal and compressed air energy storage power generation strategy, the system can efficiently utilize solar thermal energy during sunny daytime hours to store high-temperature, high-density, and long-term heat in molten salt, providing a stable and reliable energy foundation for subsequent power generation. Furthermore, the system utilizes electricity directly generated from low-cost or renewable energy sources for compressed air energy storage, further improving energy efficiency.

[0024] 2) Flexible Scheduling and Response: During peak electricity demand periods, the system uses heat exchange between compressed air and molten salt to drive expanders to generate electricity, achieving efficient and flexible energy utilization. This scheduling method can adjust power generation in real time based on grid demand, effectively responding to fluctuations in the electricity market and improving the flexibility and responsiveness of the energy system.

[0025] 3) Backup Energy System Enhances Reliability: Notably, this utility model incorporates a backup energy system that generates electricity through the combustion of a mixture of compressed air and fuel. This design can rapidly activate and provide stable and reliable energy support in emergency situations, such as when the solar thermal energy storage supply is insufficient or interrupted, or when there is insufficient stored energy, ensuring the continuity and stability of the energy supply. This backup mechanism significantly enhances the safety and reliability of the energy system and reduces the risks associated with energy shortages or interruptions.

[0026] 4) Comprehensive Solution Enhances Overall Efficiency: This integrated solution not only improves energy efficiency but also effectively enhances the safety and reliability of the energy system. By integrating multiple technologies, including solar thermal energy storage, compressed air energy storage, and fuel backup power generation, the system achieves an efficient, stable, and reliable energy supply. This provides a new solution for the complementary combined power generation of renewable energy and fuel backup, driving innovation and development in the energy sector. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Attachment Figure 1 This is a schematic structural diagram of the utility model's compressed air-molten salt combined energy storage solar thermal power generation system.

[0029] Attachment Figure 2 This is a structural diagram of a power generation system with fuel backup and complementation according to the utility model.

[0030] Attachment Figure 3It is a structural schematic diagram of the energy storage process of the utility model.

[0031] Attachment Figure 4 It is a structural schematic diagram of the power generation process of the utility model.

[0032] Attachment Figure 5 This is a schematic diagram of the fuel backup power generation process structure of the utility model Figure 1 .

[0033] Attachment Figure 6 This is a schematic diagram of the fuel backup power generation process structure of the utility model Figure 2 .

[0034] The meanings of the serial numbers in the above figure are as follows: 1. Cooling tower; 21. Cooling water pump; 22. Booster pump; 3. Multi-stage cooler; 4. Multi-stage isothermal compressor; 5. Heat recovery device; 6. Compressed air storage tank; 7. Water reservoir; 8. Multi-stage combustion chamber; 9. Multi-stage isothermal expander; 10. Multi-stage countercurrent heat exchanger; 111. High-temperature molten salt tank; 112. Low-temperature molten salt tank; 12. Solar thermal tower; 13. Heliostat field; 14. Clutch; 151. Hydraulic generator; 152. Generator; 161. First molten salt pump; 162. Second molten salt pump; 171~1711. Valves; 18. Combustion furnace; 19. Molten salt coil. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below.

[0036] Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments.

[0037] Based on the embodiments of the present invention, all other implementations obtained by persons of ordinary skill in the art without inventive effort are within the scope of protection of the present invention. To make the embodiments easier to understand, the following provides various embodiments or implementation methods to illustrate the relevant devices, modules, and functions of the present invention.

[0038] In order to enable readers of this embodiment to quickly understand the implementation of the present utility model, the working principle expressed is explained here.

[0039] As attached Figure 1 and Figure 2 As shown, a compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system includes a compressed air energy storage system, a cooling water system, a solar thermal energy storage system, a combustion energy storage backup system, and an energy storage power generation system;

[0040] As attached Figure 1As shown, the compressed air energy storage system includes a multi-stage cooler 3, a multi-stage isothermal compressor 4, a compressed air storage tank 6, a water reservoir 7, a hydraulic generator 151, and the connecting pipes therebetween. The multi-stage isothermal compressor 4 has n (n ≥ 2) compression stages, namely, a first-stage compression stage 41, a secondary compression stage 42, ..., and a final compression stage 4n. The multi-stage cooler 3 has n-1 coolers, namely, a first-stage cooler 31, a secondary cooler 32, ..., and a final cooler 3n-1. Each cooler is installed on the compressed working medium pipeline between every two compression stages of the multi-stage isothermal compressor 4. That is, the inlet / outlet of the cooler air medium channel of the multi-stage cooler 3 is respectively connected to the working medium outlet of the previous compression stage / the working medium inlet of the next compression stage of the multi-stage isothermal compressor 4.

[0041] The working fluid inlet of the first compression stage 41 of the multi-stage isothermal compressor 4 is directly connected to the environment, while the working fluid outlet of the final compression stage 4n is connected to the inlet of the working fluid channel of the compressed air storage tank 6. The hydraulic generator 151 and valve 177 are connected in series between the bottom of the compressed air storage tank 6 and the bottom end of the water reservoir 7. The hydraulic generator 151 functions to stabilize the pressure of the compressed air entering the compressed air storage tank 6 and recover some of the compressed air's energy. During this process, high-pressure compressed air enters the compressed air storage tank 6, and the water in the compressed air storage tank 6 is forced outward by the high-pressure gas. The discharged high-pressure water drives the hydraulic generator 151 to operate and generate electricity. The compressed air storage tank 6 functions to store and release the compressed air medium that has undergone multi-stage isothermal compression.

[0042] The cooling water system includes a cooling tower 1, a cooling water pump 21, a multi-stage cooler 3, and the connecting pipes therebetween. The cooling water channels of the multi-stage cooler 3, the cooling water pump 21, and the cooling tower 1 are connected by pipes to form a cooling water circulation system. The cooling water passes through the coolers of the multi-stage cooler 3 to dissipate the heat generated by each compression stage of the multi-stage isothermal compressor 4 to the outside, maintaining the compression process at a low temperature and achieving approximately "isothermal compression."

[0043] The CSP energy storage system includes a high-temperature molten salt tank 111, a low-temperature molten salt tank 112, a CSP tower 12, a heliostat field 13, a first molten salt pump 161, and connecting pipes therebetween. The first molten salt pump 161 is connected between the low-temperature molten salt tank 112 and the CSP tower 12, and the high-temperature molten salt tank 111 is directly connected to the CSP tower 12. In this way, the first molten salt pump 161 transports the low-temperature molten salt from the low-temperature molten salt tank 112 after heat exchange to the heat absorber of the CSP tower 12. The CSP tower 12 receives sunlight reflected by the heliostats in the heliostat field 13, heats the low-temperature molten salt into high-temperature molten salt, and then stores it in the high-temperature molten salt tank 111.

[0044] like Figure 2As shown, the combustion energy storage backup system includes a high-temperature molten salt tank 111, a low-temperature molten salt tank 112, a combustion furnace, a molten salt coil, a first molten salt pump 161, and connecting pipes therebetween; the molten salt coil 19 is evenly arranged in the combustion furnace 18, one end of the molten salt coil 19 is connected to the outlet of the first molten salt pump 161 through a valve 1710, the inlet of the first molten salt pump 161 is connected to the low-temperature molten salt storage tank 112, and the other end of the molten salt coil 19 is connected to the high-temperature molten salt storage tank 111 through a valve 1211. In this way, the first molten salt pump 161 transports the low-temperature molten salt from the low-temperature molten salt storage tank 112 to the molten salt coil 19 in the combustion furnace 18, and at the same time, the fuel is fed into the combustion furnace 18 for full combustion, heating the low-temperature molten salt in the molten salt coil 19 in the combustion furnace 18 into high-temperature molten salt, which is then stored in the high-temperature molten salt storage tank 111. The fuel in the combustion furnace 18 is coal, pulverized coal, biomass, coal gas, natural gas, hydrogen, liquid fuel, etc.

[0045] like Figure 4 As shown, the energy storage and power generation system includes a heat recovery device 5, a compressed air storage tank 6, a water reservoir 7, a multi-stage isothermal expander 9, a multi-stage countercurrent heat exchanger 10, a high-temperature molten salt tank 111, a low-temperature molten salt tank 112, a second molten salt pump 162, a booster pump 22, a generator 152, and connecting pipes therebetween. The multi-stage isothermal expander 9 has m (m ≥ 2) expansion stages, namely, a first expansion stage 91, a secondary expansion stage 92, ..., and a final expansion stage 9m. The multi-stage countercurrent heat exchanger 10 has m countercurrent heat exchangers corresponding one-to-one to the expansion stages of the multi-stage isothermal expander 9, namely, a first countercurrent heat exchanger 101, a secondary countercurrent heat exchanger 102, a tertiary countercurrent heat exchanger 103, ..., and a final countercurrent heat exchanger 10m. The countercurrent heat exchanger of the multi-stage countercurrent heat exchanger 10 is installed on the expansion working fluid pipeline between every two expansion stages of the multi-stage isothermal expander 9 or on the working fluid pipeline between the heat recovery device 5 and the first-stage isothermal expander 91 of the multi-stage isothermal expander 9, that is, the first-stage countercurrent heat exchanger 101 is installed on the working fluid pipeline between the working fluid channel of the heat recovery device 5 and the first-stage expansion stage 91 of the multi-stage isothermal expander 9; the inlet / outlet of the remaining countercurrent heat exchangers of the multi-stage countercurrent heat exchanger 10 except the first-stage countercurrent heat exchanger 101 are respectively connected to the working fluid pipeline between the working fluid outlet of the previous expansion stage / the working fluid inlet of the next expansion stage of the multi-stage isothermal expander 9. The molten salt medium inlet of each stage of the multi-stage counterflow heat exchanger 10 is connected to the outlet of the second molten salt pump 162, the inlet of the second molten salt pump 162 is connected to the high-temperature molten salt storage tank 111, and the outlet of each stage of the multi-stage counterflow heat exchanger 10 is connected to the low-temperature molten salt storage tank 112.

[0046] The compressed air storage tank 6 is connected to the working fluid channel inlet of the heat recovery device 5 through a pipeline, and the outlet of the working fluid channel of the heat recovery device 5 is respectively connected to the working fluid inlet of the first-stage countercurrent heat exchanger 101 of the multi-stage countercurrent heat exchanger 10; the exhaust gas channel inlet of the heat recovery device 5 is connected to the exhaust gas outlet of the last expansion stage 9m of the multi-stage isothermal expander 9, and the exhaust gas channel outlet of the heat recovery device 5 is connected to the environment.

[0047] The booster pump 22 and the valve 176 are connected in series between the bottom of the compressed air storage tank 6 and the bottom end of the water reservoir 7. The booster pump 22 injects water into the compressed air storage tank 6, and the water compresses the air in the compressed air storage tank 6 and enters the heat recovery device 5.

[0048] like Figure 1 As shown, the compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system of the present invention includes a clutch 14, which is connected between the multi-stage isothermal compressor 4 and the multi-stage isothermal expander 9 to achieve the disconnection of the rotational connection between the multi-stage isothermal compressor 4 and the multi-stage isothermal expander 9.

[0049] The multi-stage isothermal compressor 4, the multi-stage isothermal expander 9, and the generator 152 are mounted on the same rotating shaft; the generator 152 is an AC generator, and the multi-stage isothermal expander 9 drives the AC generator 152 to generate electricity;

[0050] like Figure 6 As shown, a compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system includes a multi-stage combustion chamber 8, which has m combustion chambers corresponding one to one to the expansion stages of the multi-stage isothermal expander 9, namely the first-stage combustion chamber 81, the secondary combustion chamber 82, the tertiary combustion chamber 83, ..., and the final combustion chamber 8m. The combustion chambers of the multi-stage combustion chamber 8 are installed on the expansion working medium pipeline between every two expansion stages of the multi-stage isothermal expander 9 or on the working medium pipeline between the heat recovery device 5 and the first-stage isothermal expander 91 of the multi-stage isothermal expander 9, that is, the first-stage combustion chamber 81 is installed on the working medium pipeline between the working medium channel of the heat recovery device 5 and the first-stage expansion stage 91; the inlet / outlet of the remaining combustion chambers of the multi-stage combustion chamber 8 except the first-stage combustion chamber 81 are respectively connected to the working medium outlet of the previous expansion stage / the working medium inlet of the next expansion stage of the multi-stage isothermal expander 9.

[0051] The function of the heat recovery device 5 is to recover the heat of the high-temperature exhaust gas from the final expansion stage 9m of the multi-stage isothermal expansion stage 9, and use the recovered heat to preheat the compressed air before doing work; that is, the high-pressure and low-temperature compressed air exchanges heat with the exhaust gas discharged from the final expansion stage 9m in the heat recovery device 5, and the high-pressure and low-temperature compressed air absorbs the heat of the exhaust gas, is preheated once, and then enters the first-stage countercurrent heat exchanger 101 or the first-stage combustion chamber 81.

[0052] Each combustion chamber of the multi-stage combustion chamber 5 is filled with a fixed amount of fuel, which is mixed with the circulating working medium air entering the combustion chamber and then fully combusted to produce exhaust gas. Each expansion stage of the multi-stage isothermal expander 9 is connected to a combustion chamber, and is driven by the exhaust gas produced by the combustion chamber to generate power for electricity generation.

[0053] The fuel in the combustion chamber 5 is coal gas, natural gas, hydrogen, liquid fuel, etc.

[0054] The power generation system of the present invention has three working cycle processes, namely energy storage process, power generation process and fuel backup power generation process.

[0055] Please refer to Figure 3 As shown, the energy storage process consists of two parts. The first is compressed air energy storage, which uses valley electricity and clean energy (such as solar and wind energy) to drive a multi-stage isothermal compressor 4 to compress and store air, achieving peak-to-valley energy shifting. The second is solar thermal energy storage in a tower-type solar thermal system during daytime hours when solar energy is abundant.

[0056] The compressed air energy storage cycle is as follows: Low-cost electrical energy drives the multi-stage isothermal compressor 4 to begin operation. The first compression stage 41 of the multi-stage isothermal compressor 4 draws working air from the atmosphere and performs initial compression, raising both the temperature and pressure of the working air. To prevent the working air temperature from rising excessively, the compressed working air in the first compression stage 41 enters the first cooler 31 of the multi-stage cooler 3 for cooling. The cooled working air then enters the secondary compression stage 42 for secondary pressurization. After secondary pressurization, the working air enters the secondary cooler 32 for further cooling. This process continues until the working air is compressed to a predetermined pressure in the final compression stage 4n. After all compression and cooling steps are completed, the working air enters the compressed air storage tank 6 for storage. In the compressed air storage tank 6, the high-pressure gas drives the water inside, which in turn drives the hydraulic generator 151 to operate and generate electricity. The water output from the hydraulic generator 151 ultimately flows into the water reservoir 7, completing the energy storage process. During this process, the cooling tower 1 provides a steady supply of cooling water to each stage of the multi-stage cooler 3 through the cooling water pump 21 to ensure that the heat generated by each compression stage of the multi-stage isothermal compressor 4 can be effectively dissipated to the external environment, thereby keeping the entire compression process at a lower temperature and achieving approximate "isothermal compression".

[0057] The CSP tower system's CSP energy storage cycle: The molten salt in the low-temperature molten salt storage tank 112 is steadily transported to the heat absorber at the top of the CSP tower 12, driven by the first molten salt pump 161. Simultaneously, the heliostat field 13 precisely focuses sunlight onto the heat absorber, which efficiently converts this focused light energy into heat, heating the molten salt to a high temperature. Once heated, the high-temperature molten salt, continuously pumped by the first molten salt pump 161, is smoothly transferred to the high-temperature molten salt storage tank 111 for storage and subsequent use.

[0058] Energy storage and power generation process:

[0059] The entire power generation cycle process is as follows Figure 4 As shown. First, the booster pump 22 injects water into the compressed air storage tank 6 to compress the air in the storage tank and return it, thereby increasing the pressure of the compressed air. Subsequently, the compressed air directly enters the heat recovery device 5 and undergoes heat exchange with the high-temperature final exhaust gas discharged from the final expansion stage 9m of the multi-stage isothermal expander 9. The compressed air is preheated and absorbs heat. After completing the heat exchange, the compressed air enters the compressed air channel of the first-stage countercurrent heat exchanger 101 of the multi-stage countercurrent heat exchanger 10. At the same time, the second molten salt pump 162 sends the high-temperature molten salt from the high-temperature molten salt storage tank 111 into the molten salt medium channel of the first-stage countercurrent heat exchanger 101, and the high-temperature molten salt transfers heat to the compressed air. After absorbing heat, the temperature of the compressed air rises, and the pressure remains unchanged, which then drives the first-stage expansion stage 91 of the multi-stage isothermal expander 9 to perform work. The compressed air discharged from the first-stage expansion stage 91 after performing work enters the secondary countercurrent heat exchanger 102 of the multi-stage countercurrent heat exchanger 10. Here, the compressed air again undergoes heat exchange with the high-temperature molten salt coming out of the high-temperature molten salt storage tank 111, and the heated compressed air then drives the secondary expansion stage 92 of the multi-stage isothermal expander 9 to produce power. This heating-work process is repeated before each expansion stage of the multi-stage isothermal expander 9. Before driving each expansion stage of the multi-stage isothermal expander 9, the power generation cycle medium (i.e., compressed air) will first undergo a heating process to ensure that there is enough energy to drive the expansion stage to produce power. Until the last expansion stage 9m of the multi-stage isothermal expander 9, the exhaust gas discharged from this stage directly enters the heat recovery device 5 for heat recovery. The exhaust gas after heat recovery is finally discharged into the atmosphere. In this way, the repetitive operation completes the entire compressed air energy storage power generation cycle.

[0060] In this process, in order to achieve approximate isothermal expansion, the compressed air first enters the countercurrent heat exchanger connected in front of each expansion stage before entering each expansion stage of the multi-stage isothermal expander 9, and exchanges heat with the high-temperature molten salt coming out of the high-temperature molten salt storage tank 111, absorbing the heat of the high-temperature molten salt to drive the corresponding expansion stage of the multi-stage isothermal expander 9 to do work.

[0061] Fuel backup power generation process 1, such as Figure 5As shown:

[0062] First, the first molten salt pump 161 transports the low-temperature molten salt in the low-temperature molten salt storage tank 112 to the molten salt coil 19 in the combustion furnace 18. At the same time, the fuel is sent into the combustion furnace 18 for full combustion, and the low-temperature molten salt in the molten salt coil 19 in the combustion furnace 18 is heated to high-temperature molten salt, which is then stored in the high-temperature molten salt storage tank 111 to complete the molten salt heat storage.

[0063] Secondly, the first compression stage 41 of the multi-stage isothermal compressor 4 inhales working medium air from the atmosphere for compression, and the temperature and pressure of the working medium air rise; in order to prevent the working medium temperature from rising too much, the working medium air that has been pressurized once by the first compression stage 41 directly enters the first-stage cooler 31 of the multi-stage cooler 3 for cooling, and the working medium air that has been pressurized once after cooling enters the secondary compression stage 42 for secondary pressurization, and the working medium air that has been pressurized twice enters the secondary cooler 32 for cooling, and so on until it is compressed to a predetermined pressure in the final compression stage 4n. The compressed working medium air directly enters the heat recovery device 5, and exchanges heat with the high-temperature final exhaust gas discharged from the final expansion stage 9m of the multi-stage isothermal expander 9 in the heat recovery device 5, and then enters the compressed air channel of the first-stage countercurrent heat exchanger 101 of the multi-stage countercurrent heat exchanger 10. At the same time, under the action of the second molten salt pump 162, the high-temperature molten salt in the high-temperature molten salt storage tank 111 is sent to the molten salt medium channel of the first-stage countercurrent heat exchanger 101, and the heat of the high-temperature molten salt is transferred to the compressed air. The compressed air absorbs the heat of the high-temperature molten salt and drives the multi-stage isothermal expansion. The first expansion stage 91 of the multi-stage isothermal expander 9 performs work, and the compressed air after the work is cooled and depressurized; the cooled and depressurized compressed air discharged from the first expansion stage 91 of the multi-stage isothermal expander 9 enters the secondary countercurrent heat exchanger 102 of the multi-stage countercurrent heat exchanger 10, and the cooled and depressurized compressed air discharged from the first expansion stage 91 is heated by the high-temperature molten salt coming out of the high-temperature molten salt storage tank 111 in the secondary countercurrent heat exchanger 102, and then the heated compressed air drives the secondary expansion stage 92 of the multi-stage isothermal expander 9 to generate power and perform work and then cool down and depressurize again; in this way, the working medium of the power generation cycle is cooled and depressurized each time Before driving each expansion stage of the multi-stage isothermal expander 9, it first undergoes a temperature increase process (i.e., the power generation circulating fluid is heated by the high-temperature molten salt discharged from the high-temperature molten salt storage tank 111 in the corresponding countercurrent heat exchanger). The heated power generation circulating fluid then drives the corresponding expansion stage of the multi-stage isothermal expander 9 to generate power and generate electricity, all the way to the final expansion stage 9m of the multi-stage isothermal expander 9. The exhaust gas discharged from the final expansion stage 9m of the multi-stage isothermal expander 9 directly enters the heat recovery device 5 for heat recovery, and the exhaust gas discharged from the heat recovery device 5 directly enters the air. This repetitive operation completes the continuous backup power generation process.

[0064] Fuel backup power generation process two, such as Figure 6 As shown:

[0065] The first compression stage 41 of the multi-stage isothermal compressor 4 draws in working air from the atmosphere for compression, and the temperature and pressure of the working air both rise; in order to prevent the working temperature from rising too much, the working air that has been pressurized once through the first compression stage 41 directly enters the first cooler 31 of the multi-stage cooler 3 for cooling, and after cooling, the working air that has been pressurized once enters the secondary compression stage 42 for secondary pressurization, and the working air that has been pressurized twice enters the secondary cooler 32 for cooling, and so on until it is compressed to a predetermined pressure in the final compression stage 4n, and then directly enters the heat recovery device 5, and in the heat recovery device 5, it exchanges heat with the high-temperature final exhaust gas discharged from the final expansion stage 9m of the multi-stage isothermal expander 9, and the compressed air absorbs the heat of the high-temperature final exhaust gas, and then enters the first combustion chamber 81 of the multi-stage combustion chamber 8, and at the same time, the first combustion chamber 81 is injected with fuel and mixed with the compressed air entering the combustion chamber. The exhaust gas is fully burned to produce primary exhaust gas; the first expansion stage 91 of the multi-stage isothermal expander 9 is connected to the first combustion chamber 81 of the multi-stage combustion chamber 8, and the first expansion stage 91 of the multi-stage isothermal expander 9 is driven by the incoming primary exhaust gas to generate power and primary exhaust gas that is cooled and reduced in pressure after doing work; the cooled and reduced-pressure primary exhaust gas discharged from the first expansion stage 91 of the multi-stage isothermal expander 9 enters the secondary combustion chamber 81 of the multi-stage combustion chamber 8, is mixed with the injected fuel and is fully burned again to produce secondary exhaust gas, and then the secondary exhaust gas enters the secondary expansion stage 92 of the multi-stage isothermal expander 9, and the secondary expansion stage 92 is driven to generate power and secondary exhaust gas that is cooled and reduced in pressure after doing work; until the last expansion stage 9m of the multi-stage isothermal expander 9, the last expansion stage 9m is driven to generate power and the last exhaust gas that is cooled and reduced in pressure after doing work; the last exhaust gas is not directly discharged into the air, but directly enters the heat recovery device 5 for heat recovery. The temperature of the final exhaust gas discharged from the heat recovery device 5 is close to the ambient temperature and is directly discharged into the environment, thus completing the fuel backup power generation cycle process.

[0066] As described above, during energy storage power generation, the multi-stage isothermal expander 9 drives the AC generator 152 to generate electricity. During backup power generation, a starting power supply is first provided to the multi-stage isothermal compressor 4, and then the multi-stage isothermal expander 9 drives the AC generator 152 and the multi-stage isothermal compressor 4 simultaneously.

[0067] This utility model realizes efficient, stable and reliable energy supply through the organic combination of multiple technologies such as solar thermal energy storage, compressed air energy storage and fuel backup power generation. It provides a new solution for the complementary joint power generation of renewable energy and fuel backup, improves energy utilization efficiency, effectively enhances the safety and reliability of the energy system, and promotes innovation and development in the energy field.

Claims

1. A compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system, characterized in that: Including compressed air energy storage system, cooling water system, solar thermal energy storage system, combustion energy storage backup system and energy storage power generation system; The compressed air energy storage system includes a multi-stage cooler, a multi-stage isothermal compressor, a compressed air storage tank, a water reservoir, a hydraulic generator, and connecting pipes therebetween; the multi-stage isothermal compressor has multiple compression stages, and the multi-stage cooler has multiple coolers; the inlet / outlet of the cooler air medium channel of the multi-stage cooler is respectively connected to the working medium outlet of the previous compression stage / the working medium inlet of the next compression stage of the multi-stage isothermal compressor; The working medium inlet of the first compression stage of the multi-stage isothermal compressor is directly connected to the environment, and the working medium outlet of the last compression stage is connected to the inlet of the working medium channel of the compressed air storage tank; the hydraulic generator is connected between the bottom of the compressed air storage tank and the bottom end of the water reservoir; The cooling water system includes a cooling tower, a cooling water pump, a multi-stage cooler and connecting pipes therebetween; the cooling water channels of the multi-stage cooler, the cooling water pump and the cooling tower are connected by pipes to form a cooling water circulation system; The solar thermal energy storage system includes a high-temperature molten salt tank, a low-temperature molten salt tank, a solar thermal tower, a heliostat field, a first molten salt pump, and connecting pipes between them; the first molten salt pump is connected between the low-temperature molten salt tank and the solar thermal tower, and the high-temperature molten salt tank is directly connected to the solar thermal tower; The combustion energy storage backup system includes a high-temperature molten salt tank, a low-temperature molten salt tank, a combustion furnace, a molten salt coil, a first molten salt pump, and connecting pipes between them; the molten salt coil is evenly arranged in the combustion furnace, one end of the molten salt coil is connected to the outlet of the first molten salt pump, the inlet of the first molten salt pump is connected to the low-temperature molten salt storage tank, and the other end of the molten salt coil is connected to the high-temperature molten salt storage tank; The energy storage and power generation system includes a heat recovery device, a compressed air storage tank, a water reservoir, a multi-stage isothermal expander, a multi-stage countercurrent heat exchanger, a high-temperature molten salt tank, a low-temperature molten salt tank, a second molten salt pump, a pressure pump, a generator and connecting pipes therebetween; the multi-stage isothermal expander has multiple expansion stages, and the multi-stage countercurrent heat exchanger has multiple countercurrent heat exchangers corresponding one-to-one to the expansion stages of the multi-stage isothermal expander; the countercurrent heat exchanger of the multi-stage countercurrent heat exchanger is installed on the expansion working medium pipeline between every two expansion stages of the multi-stage isothermal expander or on the working medium pipeline between the heat recovery device and the first-stage isothermal expander of the multi-stage isothermal expander; the molten salt medium inlet of each stage of the countercurrent heat exchanger of the multi-stage countercurrent heat exchanger is connected to the outlet of the second molten salt pump, the inlet of the second molten salt pump is connected to the high-temperature molten salt storage tank, and the outlet of each stage of the countercurrent heat exchanger of the multi-stage countercurrent heat exchanger is connected to the low-temperature molten salt storage tank; The compressed air storage tank is connected to the working medium channel inlet of the heat recovery device through a pipeline, and the outlet of the working medium channel of the heat recovery device is respectively connected to the working medium inlet of the first-stage countercurrent heat exchanger of the multi-stage countercurrent heat exchanger; the exhaust gas channel inlet of the heat recovery device is connected to the exhaust gas outlet of the last expansion stage of the multi-stage isothermal expander, and the exhaust gas channel outlet of the heat recovery device is connected to the environment; The booster pump is connected between the bottom of the compressed air storage tank and the bottom end of the water reservoir.

2. A compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system according to claim 1, characterized in that: A clutch is also included, wherein the clutch is connected between the multi-stage isothermal compressor and the multi-stage isothermal expander.

3. The compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system according to claim 1, characterized in that: The multi-stage isothermal compressor, the multi-stage isothermal expander and the generator are installed on the same rotating shaft, and the multi-stage isothermal expander drives the generator to generate electricity.

4. The compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system according to claim 1, characterized in that: The first-stage countercurrent heat exchanger of the multi-stage countercurrent heat exchanger is installed on the working medium pipeline between the working medium channel of the heat recovery device and the first-stage expansion stage of the multi-stage isothermal expander; the inlets / outlets of the remaining countercurrent heat exchangers of the multi-stage countercurrent heat exchanger except the first-stage countercurrent heat exchanger are respectively connected to the working medium outlet of the previous expansion stage / the working medium inlet of the next expansion stage of the multi-stage isothermal expander.

5. The compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system according to claim 1, characterized in that: It comprises a multi-stage combustion chamber, which has a plurality of combustion chambers corresponding one to one to the expansion stages of the multi-stage isothermal expander; the combustion chambers of the multi-stage combustion chamber are installed on the expansion working fluid pipeline between every two expansion stages of the multi-stage isothermal expander or on the working fluid pipeline between the heat recovery device and the first-stage isothermal expander of the multi-stage isothermal expander.

6. A compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system according to claim 5, characterized in that: The working fluid inlet of the first-stage combustion chamber of the multi-stage combustion chamber is connected to the outlet of the working fluid channel of the heat recovery device; the inlet / outlet of the combustion chamber other than the first-stage combustion chamber of the multi-stage combustion chamber is respectively connected to the working fluid outlet / working fluid inlet of the previous expansion stage / next expansion stage of the multi-stage isothermal expander.

7. The compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system according to claim 5, characterized in that: The fuel in the multi-stage combustion chamber is one of coal gas, natural gas, hydrogen and liquid fuel.

8. The compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system according to claim 1, characterized in that: The fuel in the combustion furnace is a mixture of one or more of coal, coal powder, biomass, coal gas, natural gas, hydrogen and liquid fuel.

9. The compressed air-molten salt combined energy storage solar thermal-fuel backup complementary power generation system according to claim 1, characterized in that: The heat recovery device is a counter-flow heat exchanger.

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