Heat supply system and photo-thermal molten salt power station and coal power unit coupled power generation system

Abstract

The invention discloses a heat supply system and a photo-thermal fused salt power station and coal power unit coupled power generation system, the heat supply system comprises a fused salt tower type heat absorption subsystem, a power plant fused salt heat release subsystem and a pipeline, and the fused salt tower type heat absorption subsystem comprises a heat absorber; the power plant fused salt heat release subsystem comprises a heat exchanger; the pipeline is connected between the fused salt tower type heat absorption subsystem and the power plant fused salt heat release subsystem, the pipeline, the heat absorber and the heat exchanger jointly form a circulation flow path, fused salt is suitable for flowing in the circulation flow path, the length of the pipeline is L, and L is larger than or equal to 1 km and smaller than or equal to 30 km. The fused salt can effectively collect solar energy and convert the solar energy into heat energy. The fused salt is heated to a high temperature in the heat absorber and then is transmitted to the heat exchanger to release heat for power generation or heat supply. Sectional multi-stage pressurized conveying is adopted, so that the problems of overlarge temperature drop, overlarge pressure drop, insufficient pumping power and the like are prevented. Cross-region heat supply can be achieved by limiting the length of the pipeline, the heat supply range is expanded, and the energy utilization efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of molten salt heating and coal-fired unit power generation, and specifically to a heating system and a power generation system in which a solar thermal molten salt power station is coupled with a coal-fired power unit. Background Art

[0002] In the existing technology, molten salt tower solar power stations complete the steps of molten salt heat absorption, molten salt and water heat exchange to generate steam, and steam power generation at the power station. Since solar energy absorption needs to be directly performed at the power station location, this means that the power station must be built in a place with abundant light resources. The power station usually needs to be built in a remote area far away from the power load center, resulting in increased costs and losses in power transmission.

[0003] In the process from sunlight to final electricity output, each step of conversion will bring about a certain amount of energy loss, such as thermal radiation loss during heat absorption, heat conduction loss during molten salt flow, and mechanical loss during steam power generation. The energy utilization efficiency of molten salt tower solar power stations in the entire power generation process is low. Summary of the Invention

[0004] In view of the above problems, a first object of the present invention is to provide a heating system that can improve the energy transmission efficiency of the heating system.

[0005] The second object of the present invention is to propose a power generation system coupling a solar thermal molten salt power station with a coal-fired power unit, including the heating system in the above embodiment.

[0006] According to an embodiment of the first aspect of the present invention, a heating system includes: a molten salt tower heat absorption subsystem, a power plant molten salt heat release subsystem and a pipeline, the molten salt tower heat absorption subsystem includes a heat absorber; the power plant molten salt heat release subsystem includes a heat exchanger; the pipeline is connected between the molten salt tower heat absorption subsystem and the power plant molten salt heat release subsystem, the pipeline, the heat absorber and the heat exchanger together constitute a circulation flow path, the molten salt is suitable for flowing in the circulation flow path, the length of the pipeline is L, and L satisfies: 1km≤L≤30km.

[0007] According to the heating system of an embodiment of the present invention, the molten salt tower heat absorption subsystem and the molten salt heat release subsystem of the power plant are connected by a pipeline. The molten salt serves as a transmission and storage medium for thermal energy, which can effectively collect solar energy and convert it into usable thermal energy. The molten salt is heated to a high temperature in the heat absorber and then transferred to the heat exchanger to release heat for power generation or heating. The use of segmented multi-stage pressurized transportation prevents problems such as excessive temperature drop, excessive pressure drop, and insufficient pumping power. By limiting the length of the pipeline, cross-regional heating can be achieved, thereby expanding the scope of heating and improving the efficiency of energy utilization and the flexibility of distribution.

[0008] In some embodiments, the pipeline includes a first pipeline and at least one second pipeline, the two ends of the first pipeline are respectively connected to the heat absorber and the heat exchanger, the two ends of the second pipeline are respectively connected to the heat absorber and the heat exchanger, and the flow direction of the molten salt in the first pipeline is opposite to the flow direction of the molten salt in the second pipeline.

[0009] In some embodiments, the molten salt tower heat absorption subsystem also includes a first high-temperature molten salt storage tank and a first low-temperature molten salt storage tank. The first high-temperature molten salt storage tank is arranged on the first pipeline, and the first low-temperature molten salt storage tank is arranged on the second pipeline. The molten salt is suitable for flowing out from the first low-temperature molten salt storage tank to the heat absorber for heat exchange and then flowing into the first high-temperature molten salt storage tank; the power plant molten salt heat release subsystem also includes a second high-temperature molten salt storage tank and a second low-temperature molten salt storage tank. The second high-temperature molten salt storage tank is arranged on the first pipeline, and the second low-temperature molten salt storage tank is arranged on the second pipeline. The molten salt is suitable for flowing out from the second high-temperature molten salt storage tank to the heat exchanger for heat exchange and then flowing into the second low-temperature molten salt storage tank.

[0010] In some embodiments, the pipe is provided with corners, and the positions of the corners are higher than the positions of the two end portions of the pipe.

[0011] In some embodiments, the corner angle is α, where α satisfies: 0.5°≤α≤5°.

[0012] In some embodiments, the pipeline includes a first pipeline and a plurality of second pipelines, and the plurality of second pipelines are evenly spaced along the circumference of the first pipeline.

[0013] In some embodiments, the cross-sectional area of the first pipe is S1, the cross-sectional area of the second pipe is S2, the cross-sectional area S1 of the first pipe is greater than the cross-sectional area S2 of the second pipe, and the number of the second pipes is N, wherein S1, S2 and N satisfy: 0.196m 2 ≤S1≤0.503m 2 , 0.033m 2 ≤S2≤0.126m 2 , S1=N*S2.

[0014] According to the second embodiment of the present invention, a power generation system of a solar thermal molten salt power station coupled with a coal-fired power unit includes a heating system according to the first embodiment of the present invention.

[0015] In some embodiments, it also includes: a mirror field subsystem and a power plant boiler power generation subsystem, the molten salt tower heat absorption subsystem is coupled with the mirror field subsystem, the mirror field subsystem is used to reflect sunlight and transfer heat to the heat absorber; the power plant molten salt heat release subsystem is arranged in the power plant boiler power generation subsystem, the power plant boiler power generation subsystem is arranged downstream of the power plant molten salt heat release subsystem of the heating system, and the heat exchange medium is suitable for flowing through the heat exchanger of the power plant molten salt heat release subsystem and then flowing to the power plant boiler power generation subsystem. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of a heating system according to an embodiment of the present invention;

[0017] Figure 2 Schematic diagram of a cross section of a pipeline according to an embodiment of the present invention.

[0018] Reference numerals:

[0019] 100. Power generation system; 1. Heating system; 10. Mirror field subsystem; 11. Heliostat; 20. Molten salt tower heat absorption subsystem; 21. Heat absorption tower; 22. Heat absorber; 23. First high-temperature molten salt storage tank; 24. First low-temperature molten salt storage tank; 30. Pipeline; 31. First pipeline; 32. Second pipeline; 40. Power plant molten salt heat release subsystem; 41. Heat exchanger; 42. Second high-temperature molten salt storage tank; 43. Second low-temperature molten salt storage tank; 50. Power plant boiler power generation subsystem. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Figure 1 and Figure 2 The heat supply system 1 according to an embodiment of the present invention is described, which includes: a molten salt tower heat absorption subsystem 20 , a power plant molten salt heat release subsystem 40 and a pipeline 30 .

[0022] Specifically, if Figure 1 and Figure 2 As shown, the molten salt tower heat absorption subsystem 20 includes a heat absorber 22; the power plant molten salt heat release subsystem 40 includes a heat exchanger 41; the pipeline 30 is connected between the molten salt tower heat absorption subsystem 20 and the power plant molten salt heat release subsystem 40, and the pipeline 30, the heat absorber 22 and the heat exchanger 41 together construct a circulation flow path, and the molten salt is suitable for flowing in the circulation flow path. The length of the pipeline 30 is L, and L satisfies: 1km≤L≤30km.

[0023] The molten salt tower heat absorption subsystem 20 includes a heat absorption tower 21, with a heat absorber 22 located at the top. The molten salt tower heat absorption subsystem 20 is coupled to the mirror field subsystem 10. The mirror field subsystem 10 is equipped with multiple heliostats 11, which reflect sunlight and focus it onto the heat absorber 22 at the top of the heat absorption tower 21. The heat absorber 22 converts the solar energy into thermal energy. Molten salt flows through a circulation path formed by pipes 30, the heat absorber 22, and the heat exchanger 41. In this circulation path, the molten salt serves as a heat transfer and storage medium. As the low-temperature molten salt flows through the heat absorber 22, it exchanges heat with the absorber 22, absorbing heat and raising its temperature to become high-temperature molten salt.

[0024] The high-temperature molten salt flows through pipeline 30 to the power plant's molten salt heat release subsystem 40 and then to heat exchanger 41 within the power plant's molten salt heat release subsystem 40 to complete heat exchange. Heat exchanger 41 is provided with a heat exchange medium. The high-temperature molten salt exchanges heat with the heat exchange medium in heat exchanger 41, and the heat carried by the high-temperature molten salt is transferred to the heat exchange medium within heat exchanger 41. During this process, the temperature of the high-temperature molten salt decreases to become low-temperature molten salt. The low-temperature molten salt then flows back through pipeline 30 to the molten salt tower heat absorption subsystem 20 and back to the heat absorber 22 to begin the heat exchange process, thus forming a closed molten salt circulation flow path.

[0025] The power plant molten salt heat release subsystem 40 is arranged in the power plant boiler power generation subsystem 50. The power plant boiler power generation subsystem 50 is located downstream of the power plant molten salt heat release subsystem 40 of the heating system 1. The heated heat exchange medium flows to the power plant boiler power generation subsystem 50, and the heat of the heat exchange medium is used in the power generation process in the power plant boiler power generation subsystem 50.

[0026] In actual production, the location of the molten salt tower heat absorption subsystem 20 is relatively far from the location of the power plant's molten salt heat release subsystem 40. The provision of the pipeline 30 facilitates long-distance energy transmission between the molten salt tower heat absorption subsystem 20 and the power plant's molten salt heat release subsystem 40. By limiting the length of the pipeline 30, cross-regional heat supply between the molten salt tower heat absorption subsystem 20 and the power plant's molten salt heat release subsystem 40 is facilitated, thereby enabling regional deployment of the molten salt tower heat absorption subsystem 20 and the power plant's molten salt heat release subsystem 40, and further enabling cross-regional deployment of the power plant's boiler power generation subsystem 50 and the molten salt tower heat absorption subsystem 20. This allows the power generation process to be performed in the power plant's boiler power generation subsystem 50 near the actual power load center, thereby reducing the power transmission cost of the power plant's boiler power generation subsystem 50.

[0027] According to the heating system 1 of an embodiment of the present invention, the molten salt tower heat absorption subsystem 20 and the power plant molten salt heat release subsystem 40 are connected by a pipeline 30. The molten salt serves as a transmission and storage medium for thermal energy, effectively collecting solar energy and converting it into usable thermal energy. The molten salt is heated to a high temperature in the heat absorber 22 and then releases heat in the heat exchanger 41 for use in power generation or heating. The molten salt is transported by means of a segmented multi-stage pressurized system to prevent problems such as excessive temperature drop, excessive pressure drop, and insufficient pumping power. By limiting the length of the pipeline 30, cross-regional heating can be achieved, the heating range can be expanded, and the efficiency of energy utilization and the flexibility of distribution can be improved.

[0028] According to some embodiments of the present invention, Figure 1 and Figure 2 As shown, the pipeline 30 includes a first pipeline 31 and at least one second pipeline 32. The two ends of the first pipeline 31 are respectively connected to the heat absorber 22 and the heat exchanger 41, and the two ends of the second pipeline 32 are respectively connected to the heat absorber 22 and the heat exchanger 41. The flow direction of the molten salt in the first pipeline 31 is opposite to the flow direction of the molten salt in the second pipeline 32.

[0029] One end of the first pipe 31 is connected to the high-temperature molten salt outlet of the heat absorber 22, and the other end is connected to the high-temperature molten salt inlet of the heat exchanger 41. The high-temperature molten salt flows from the heat absorber 22 of the molten salt tower heat absorption subsystem 20 to the heat exchanger 41 of the power plant's molten salt heat release subsystem 40. One end of the second pipe 32 is connected to the low-temperature molten salt outlet of the heat exchanger 41, and the other end is connected to the low-temperature molten salt inlet of the heat absorber 22. The low-temperature molten salt flows from the heat exchanger 41 of the power plant's molten salt heat release subsystem 40 back to the heat absorber 22 of the molten salt tower heat absorption subsystem 20. The molten salt in the first and second pipes 31 and 32 flows in opposite directions, and the molten salt flowing in the first and second pipes 31 and 32 has different temperatures: the molten salt flowing in the first pipe 31 is higher in temperature, while the molten salt flowing in the second pipe 32 is lower in temperature.

[0030] Therefore, the pipeline 30 includes a first pipeline 31 and at least one second pipeline 32. The molten salt in the first pipeline 31 and the second pipeline 32 flows in opposite directions and has different temperatures. When the first pipeline 31 and the second pipeline 32 are laid in parallel, the heat loss generated during the transmission of the high-temperature molten salt in the first pipeline 31 can be recovered by the low-temperature molten salt in the second pipeline 32, thereby reducing the total heat loss of the heating system 1, improving the comprehensive thermal efficiency of the heating system 1, and effectively improving the energy utilization rate.

[0031] According to some embodiments of the present invention, Figure 1 and Figure 2As shown, the molten salt tower heat absorption subsystem 20 also includes a first high-temperature molten salt storage tank 23 and a first low-temperature molten salt storage tank 24. The first high-temperature molten salt storage tank 23 is arranged on the first pipeline 31, and the first low-temperature molten salt storage tank 24 is arranged on the second pipeline 32. The molten salt is suitable for flowing out from the first low-temperature molten salt storage tank 24 to the heat absorber 22 for heat exchange and then flowing into the first high-temperature molten salt storage tank 23; the power plant molten salt heat release subsystem 40 also includes a second high-temperature molten salt storage tank 42 and a second low-temperature molten salt storage tank 43. The second high-temperature molten salt storage tank 42 is arranged on the first pipeline 31, and the second low-temperature molten salt storage tank 43 is arranged on the second pipeline 32. The molten salt is suitable for flowing out from the second high-temperature molten salt storage tank 42 to the heat exchanger 41 for heat exchange and then flowing into the second low-temperature molten salt storage tank 43.

[0032] The first high-temperature molten salt storage tank 23 is used to store the high-temperature molten salt that flows out of the heat absorber 22 after absorbing heat and heating. The first low-temperature molten salt storage tank 24 is used to store the low-temperature molten salt that flows back from the heat exchanger 41 to the molten salt tower heat absorption subsystem 20. The high-temperature molten salt in the first high-temperature molten salt storage tank 23 flows through the first pipeline 31 to the second high-temperature molten salt storage tank 42. The second high-temperature molten salt storage tank 42 is used to store the high-temperature molten salt from the first high-temperature molten salt storage tank 23 and provide the high-temperature molten salt to the heat exchanger 41 for heat release. The second low-temperature molten salt storage tank 43 is used to collect and store the low-temperature molten salt discharged from the heat exchanger 41 after heat exchange. The low-temperature molten salt in the second low-temperature molten salt storage tank 43 flows back to the first low-temperature molten salt storage tank 24 through the second pipeline 32. The low-temperature molten salt in the first low-temperature molten salt tank 24 flows to the heat absorber 22 to absorb heat and heat, thus starting the next cycle of molten salt circulation.

[0033] The arrangement of multiple molten salt storage tanks in the molten salt tower heat absorption subsystem 20 and the power plant molten salt heat release subsystem 40 can serve as molten salt buffer nodes to eliminate pressure shocks caused by sudden changes in the flow rate of the pipeline 30. The first high-temperature molten salt storage tank 23 can store high-temperature molten salt on the heat absorption side, improving the flexibility of molten salt scheduling. The first low-temperature molten salt storage tank 24 is used to receive low-temperature molten salt refluxed from the heat release side, providing a circulation basis for the heat absorption side. The second high-temperature molten salt storage tank 42 can provide a stable source of high-temperature molten salt for the heat exchanger 41, ensuring the continuity of the power generation process or heat supply in the next step. The second low-temperature molten salt storage tank 43 is used to store the cooled low-temperature molten salt, facilitating the recycling of the molten salt.

[0034] Thus, by setting up multiple molten salt storage tanks on the molten salt circulation flow path, it is possible to achieve hierarchical storage and flexible scheduling of molten salts of different temperatures, thereby enhancing the energy storage capacity and operational stability of the entire heating system 1. The setting of multiple molten salt storage tanks enables the molten salt tower heat absorption subsystem 20 to complete heat storage during the day and provide heat at night. The first high-temperature molten salt storage tank 23 can provide a stable high-temperature heat source, enabling the molten salt tower heat absorption subsystem 20 and the power plant molten salt heat release subsystem 40 to operate continuously day and night, thereby enabling the power plant boiler power generation subsystem 50 to generate electricity continuously around the clock, and realizing the cross-time energy allocation of the heating system 1. The setting of multiple molten salt storage tanks can also improve the heat exchange efficiency and operational stability of the heating system 1, build a sustainable thermal system architecture, and achieve efficient, stable and sustainable energy supply. The setting of multiple molten salt storage tanks can also enable the heating system 1 to adjust the molten salt distribution strategy between each molten salt storage tank according to load demand, thereby improving the flexibility of the heating system 1 and effectively improving the energy utilization efficiency.

[0035] According to some embodiments of the present invention, Figure 1 As shown, the pipe 30 is provided with a corner, and the position of the corner is higher than the positions of the two end portions of the pipe 30.

[0036] The pipe 30 has at least one elevated corner along the conveying path, with the corner's apex positioned higher than the connection openings at either end of the pipe 30. The corner can be located in the middle of the pipe 30, meaning that the pipe 30 has an overall structure that is elevated in the middle and lower at both ends, with a certain height difference between the middle and the ends. In some embodiments, the pipe 30 has an overall structure such as an inverted V-shape, an arched shape, or an inverted U-shape.

[0037] Thus, the setting of the high corner on the pipe 30 can prevent the molten salt from solidifying and causing the pipe 30 to be blocked. Molten salt is easy to solidify at low temperatures, especially when the heating system 1 is shut down or cooled at night. The structural design of the high corner of the pipe 30 can ensure that the molten salt flows smoothly to the molten salt storage tanks connected at both ends of the pipe 30 under the action of gravity, reducing the accumulation of molten salt inside the pipe, thereby avoiding the blockage of the pipe 30 caused by local deposition of molten salt, and ensuring the continuous energy supply of the heating system 1. When the heating system 1 needs to be repaired or shut down in an emergency, a reasonable corner structure and slope design can achieve natural reflux and emptying of the molten salt in the pipe 30, which is conducive to rapid discharge and improves the operational reliability and maintainability of the heating system 1. The corner structure can also be used to guide the flow direction of the molten salt, avoid turbulence, vortex and other adverse flow phenomena of the molten salt in the pipe, and improve the overall heat transfer efficiency.

[0038] In some embodiments, a small amount of gas may be generated during the startup or operation of the high-temperature molten salt system. A high-position corner can be set as an automatic exhaust point. For example, an exhaust valve is set at the corner of the pipeline 30. The gas can naturally rise and gather at the corner and be discharged from the pipeline 30 through the exhaust valve, avoiding gas accumulation causing gas blockage, poor flow or local overheating, thereby ensuring the operational reliability and safety of the heating system 1.

[0039] According to some embodiments of the present invention, Figure 1 and Figure 2 As shown, the turning angle is α, where α satisfies: 0.5°≤α≤5°.

[0040] By limiting the range of the corner, the flow resistance of the molten salt at the corner can be significantly reduced, the local pressure loss and the generation of turbulence can be reduced, and the overall thermal efficiency of the heating system 1 can be improved. If the corner is too small, it is easy to cause the local flow rate of the molten salt to drop, sediment or even blockage. A larger corner design helps to maintain the continuity and uniformity of the molten salt flow, reduce dead zones and retention phenomena. If the corner is too large, it is easy to cause the height difference between the corner and the end of the pipeline 30 to be too small, resulting in a decrease in the flow rate of the molten salt in the pipeline 30 to the two ends of the pipeline 30. Preferably, α = 3°.

[0041] Therefore, by limiting the range of the corner, the smooth flow of the molten salt in the pipeline 30 can be ensured, blocking can be prevented, and the operational stability, reliability and maintainability of the heating system 1 can be improved.

[0042] According to some embodiments of the present invention, Figure 1 and Figure 2 As shown, the pipeline 30 includes a first pipeline 31 and a plurality of second pipelines 32 . The plurality of second pipelines 32 are evenly spaced apart along the circumference of the first pipeline 31 .

[0043] The first pipe 31 is provided at the center, and multiple second pipes 32 are provided on the outer periphery of the first pipe 31. The multiple second pipes 32 are evenly spaced along the circumference of the first pipe 31. The diameter of the first pipe 31 is larger than that of the second pipes 32. Preferably, the number of second pipes 32 can be 4 or 6, and accordingly, the angular interval between adjacent second pipes 32 is 90° or 60°.

[0044] The first pipe 31 is suitable for circulating high-temperature molten salt, which will produce a certain amount of heat loss during the circulation process. The second pipe 32 is suitable for circulating low-temperature molten salt. The second pipe 32 is arranged on the outer periphery of the first pipe 31. The low-temperature molten salt circulating in the second pipe 32 can effectively absorb the heat emitted by the high-temperature molten salt during the circulation process. The low-temperature molten salt is preheated, which can reduce the energy consumption of reheating the low-temperature molten salt. The heat naturally emitted by the high-temperature molten salt can also reduce the risk of solidification of the low-temperature molten salt during transportation in the second pipe 32, preventing the failure of the molten salt circulation and even damage to the pipe 30. At the same time, the low-temperature molten salt can play a certain role in heat preservation for the first pipe 31 that transports the high-temperature molten salt during the reflux process, reducing the heat loss of the high-temperature molten salt in the first pipe 31.

[0045] Therefore, through the structural design of the first pipeline 31 and the second pipeline 32, the heat loss during the molten salt transportation process can be reduced, and the energy utilization and transportation efficiency can be improved. The second pipeline 32 is distributed at intervals along the circumference of the first pipeline 31, which can improve the compactness of the spatial layout of the pipeline 30, reduce the volume of the pipeline 30, and also reduce the production cost of the pipeline 30, improve the reliability of the pipeline 30, and extend the service life of the pipeline 30.

[0046] Pipeline 30 uses a segmented pressurization method to transport molten salt, that is, a relay pump station is added and pipeline 30 is divided into several shorter pipelines (600-800m). The molten salt is pressurized every time it is transported a certain distance to ensure that the molten salt in the pipe has a certain pressure to maintain flow.

[0047] According to some embodiments of the present invention, Figure 2 As shown, the cross-sectional area of the first pipe 31 is S1, the cross-sectional area of the second pipe 32 is S2, the cross-sectional area S1 of the first pipe is greater than the cross-sectional area S2 of the second pipe, and the number of the second pipes 32 is N, wherein S1, S2 and N satisfy: 0.196m 2 ≤S1≤0.503m 2 , 0.033m 2 ≤S2≤0.126m 2 , S1=N*S2.

[0048] That is, the cross-sectional area of the first pipe 31 is equal to the sum of the cross-sectional areas of the multiple second pipes 32. The same cross-sectional area ensures that the molten salt flow rate and flow rate in the first pipe 31 and the second pipe 32 remain consistent, ensuring a balanced flow rate of the molten salt in the pipe 30 and ensuring the flow stability of the molten salt throughout the entire circulation loop. Furthermore, during transportation, the molten salt flow rate in the first pipe 31 is equal to the sum of the molten salt flow rates in the multiple second pipes 32, allowing the molten salt to circulate smoothly throughout the entire circulation loop without the need for additional molten salt replenishment.

[0049] Thus, by limiting the cross-sectional area of the first pipe 31 to the cross-sectional area of the second pipe 32 to be equal, the heat loss of the first pipe 31 and the heat absorption of the second pipe 32 can be balanced, maximizing heat recovery efficiency and improving energy utilization. By limiting the range of the cross-sectional area of the first pipe 31 and the second pipe 32, the controllability of the molten salt flow rate in the pipe 30 can be improved, thereby controlling the flow rate of the molten salt and improving the overall stability and reliability of the heating system 1.

[0050] According to the second embodiment of the present invention, a power generation system 100 (hereinafter referred to as power generation system 100) coupled with a solar thermal molten salt power station and a coal-fired power unit is provided. Figure 1 and Figure 2 As shown, it includes a heating system 1 according to the embodiment of the first aspect of the present invention.

[0051] According to the power generation system 100 of the embodiment of the present invention, by applying the heating system 1 in the above embodiment, the heating system 1 serves as the heat energy input subsystem of the power generation system 100, which can provide a stable high-temperature heat source for the power generation process of the power generation system 100. The molten salt completes the processes of heat absorption, storage, heat exchange and reflux in the heating system 1, realizing closed-loop operation of the entire process from solar energy collection, heat energy storage, thermoelectric conversion to power output, effectively improving the energy utilization efficiency of the power generation system 100 and improving the operating stability of the power generation system 100.

[0052] According to some embodiments of the present invention, Figure 1 and Figure 2 As shown, it also includes: a mirror field subsystem 10 and a power plant boiler power generation subsystem 50, the molten salt tower heat absorption subsystem 20 is coupled with the mirror field subsystem 10, the mirror field subsystem 10 is used to reflect sunlight and transfer heat to the absorber 22; the power plant molten salt heat release subsystem 40 is arranged in the power plant boiler power generation subsystem 50, and the power plant boiler power generation subsystem 50 is arranged downstream of the power plant molten salt heat release subsystem 40 of the heating system 1, and the heat exchange medium is suitable for flowing through the heat exchanger 41 of the power plant molten salt heat release subsystem 40 to complete the heat exchange and then flow to the power plant boiler power generation subsystem 50 and provide heat for the power generation process of the power plant boiler power generation subsystem 50.

[0053] Specifically, the mirror field subsystem 10 consists of multiple heliostats 11. Heliostats 11 can track the sun's position in real time, reflecting and focusing sunlight onto a heat absorber 22 at the top of a heat absorption tower 21. The heat focused onto the heat absorber 22 is used to heat the low-temperature molten salt flowing through the heat absorber 22 to a high temperature. The molten salt tower heat absorption subsystem 20 includes the heat absorption tower 21, the heat absorber 22, a first high-temperature molten salt storage tank 23, and a first low-temperature molten salt storage tank 24. The high-temperature molten salt heated by the heater is stored in the first high-temperature molten salt storage tank 23. The high-temperature molten salt in the first high-temperature molten salt storage tank 23 can be transported via a first pipeline 31 to a second high-temperature molten salt storage tank 42 in the power plant's molten salt heat release subsystem 40.

[0054] The power plant's molten salt heat release subsystem 40 includes a second high-temperature molten salt storage tank 42, a second low-temperature molten salt storage tank 43, and a heat exchanger 41. The heat exchanger 41 is connected to the power plant's boiler power generation subsystem 50. The high-temperature molten salt in the second high-temperature molten salt storage tank 42 flows into the heat exchanger 41. The power plant's boiler power generation subsystem 50 then delivers a low-temperature heat exchange medium to the heat exchanger 41. The high-temperature molten salt and the low-temperature heat exchange medium exchange heat in the heat exchanger 41. The high-temperature molten salt cools down to become low-temperature molten salt, which is then fed into the second low-temperature molten salt storage tank 43. The heat exchange medium absorbs heat, raising its temperature and flowing back into the power plant's boiler power generation subsystem 50. In some embodiments, the heat exchange medium is water. Liquid water is heated in the heat exchanger 41 to become high-temperature steam. The high-temperature steam is transmitted to the power plant boiler power generation subsystem 50. The high-temperature steam enters the steam turbine to perform work to enable the generator to generate electricity. It can be selected to replace some superheated steam or reheated steam, saving some coal. After releasing heat, the steam flows through the condenser and cools to liquid water. The condensed water returns to the heat exchanger 41 to continue absorbing heat, forming a heat absorption and release circulation loop of the heat exchange medium. The low-temperature molten salt in the second low-temperature molten salt storage tank 43 returns to the first low-temperature molten salt storage tank 24 through the second pipe 32, thereby completing a cycle of the molten salt in the entire circulation loop.

[0055] An embodiment of the present invention proposes a power generation system 100 based on molten salt heat transfer and energy storage technology. Through the organic integration of the mirror field subsystem 10, the molten salt tower heat absorption subsystem 20, the power plant molten salt heat release subsystem 40 and the power plant boiler power generation subsystem 50, efficient conversion and stable operation of the entire process from solar energy collection, thermal energy storage, thermoelectric conversion to power output are achieved. The setting of the pipeline 30 realizes long-distance energy transmission, effectively improving the operating capacity and energy utilization efficiency of the power generation system 100.

[0056] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A heating system, characterized in that: include: A molten salt tower heat absorption subsystem, wherein the molten salt tower heat absorption subsystem includes a heat absorber; A power plant molten salt heat release subsystem, wherein the power plant molten salt heat release subsystem includes a heat exchanger; A pipeline is connected between the molten salt tower heat absorption subsystem and the molten salt heat release subsystem of the power plant. The pipeline, the heat absorber and the heat exchanger together constitute a circulation flow path. The molten salt is suitable for flowing in the circulation flow path. The length of the pipeline is L, and L satisfies: 1km≤L≤30km.

2. The heating system according to claim 1, characterized in that The pipeline includes a first pipeline and at least one second pipeline, the two ends of the first pipeline are respectively connected to the heat absorber and the heat exchanger, the two ends of the second pipeline are respectively connected to the heat absorber and the heat exchanger, and the flow direction of the molten salt in the first pipeline is opposite to the flow direction of the molten salt in the second pipeline.

3. The heating system according to claim 2, characterized in that The molten salt tower heat absorption subsystem further includes a first high-temperature molten salt storage tank and a first low-temperature molten salt storage tank, wherein the first high-temperature molten salt storage tank is provided on the first pipeline, and the first low-temperature molten salt storage tank is provided on the second pipeline, and the molten salt is suitable for flowing out of the first low-temperature molten salt storage tank to the heat absorber for heat exchange and then flowing into the first high-temperature molten salt storage tank; The power plant molten salt heat release subsystem also includes a second high-temperature molten salt storage tank and a second low-temperature molten salt storage tank. The second high-temperature molten salt storage tank is arranged on the first pipeline, and the second low-temperature molten salt storage tank is arranged on the second pipeline. The molten salt is suitable for flowing out of the second high-temperature molten salt storage tank to the heat exchanger for heat exchange and then flowing into the second low-temperature molten salt storage tank.

4. The heating system according to claim 3, characterized in that: The pipeline is provided with a corner, and the position of the corner is higher than the positions of the two end portions of the pipeline.

5. The heating system according to claim 4, characterized in that: The corner angle is α, wherein α satisfies: 0.5°≤α≤5°.

6. The heating system according to any one of claims 1 to 5, characterized in that: The pipeline includes a first pipeline and a plurality of second pipelines, and the plurality of second pipelines are evenly spaced along the circumference of the first pipeline.

7. The heating system according to claim 6, characterized in that The cross-sectional area of the first pipe is S1, the cross-sectional area of the second pipe is S2, the cross-sectional area S1 of the first pipe is greater than the cross-sectional area S2 of the second pipe, and the number of the second pipes is N, wherein S1, S2 and N satisfy: 0.196m 2 ≤S1≤0.503m 2 , 0.031m 2 ≤S2≤0.117m 2 , S1=N*S2.

8. A power generation system coupling a solar thermal molten salt power station with a coal-fired power unit, characterized in that: The invention comprises a heating system according to any one of claims 1 to 7.

9. The power generation system of the solar thermal molten salt power station coupled with a coal-fired power unit according to claim 8, characterized in that: Also includes: A mirror field subsystem, the molten salt tower heat absorption subsystem is coupled to the mirror field subsystem, and the mirror field subsystem is used to reflect sunlight and transfer heat to the heat absorber; The power plant boiler power generation subsystem, the power plant molten salt heat release subsystem is arranged in the power plant boiler power generation subsystem, the power plant boiler power generation subsystem is located downstream of the power plant molten salt heat release subsystem of the heating system, and the heat exchange medium is suitable for flowing through the heat exchanger of the power plant molten salt heat release subsystem and then flowing to the power plant boiler power generation subsystem.

Images