High-power-grade groove tower coupling solar thermal power generation system

Abstract

The invention belongs to the technical field of solar thermal power generation, and relates to a high-power-grade groove tower coupling solar thermal power generation system, and a heat energy storage device comprises a low-temperature fused salt storage tank, a medium-temperature fused salt storage tank and a high-temperature fused salt storage tank; a heat collecting pipe inlet and a heat collecting pipe outlet of the groove type heat collector are respectively connected with an outlet of the low-temperature fused salt storage tank and an inlet of the medium-temperature fused salt storage tank; a heat collecting tower inlet and a heat collecting tower outlet of the tower type heat collector are respectively connected with an outlet of the medium-temperature molten salt storage tank and an inlet of the high-temperature molten salt storage tank; the steam generator comprises a fused salt channel and a steam channel, and an inlet and an outlet of the fused salt channel are connected with an outlet of the high-temperature fused salt storage tank and an inlet of the low-temperature fused salt storage tank respectively; a steam inlet and a water supply outlet of the steam turbine are connected with an outlet and an inlet of the steam channel respectively. According to the invention, the advantage of high optical efficiency of a groove type heat collector and the advantage of high temperature of a tower type heat collector are combined, and the performance improvement bottleneck of a single system in the construction of a high-power solar thermal power generation system is broken through.

Description

Technical Field

[0001] The present invention relates to the technical field of solar thermal power generation, and in particular to a trough-tower coupled solar thermal power generation system, or a high-power trough-tower coupled solar thermal power generation system. Background Art

[0002] As an important part of the renewable energy field, CSP technology has made significant progress in recent years around the world. This technology is mainly achieved through two core technical routes: tower collector system (or tower system) and trough collector system (or trough system).

[0003] The tower solar collector system uses a large number of precisely designed heliostats to accurately focus sunlight onto a high-rise solar collector tower, converting solar energy into heat energy, which in turn drives a steam turbine to generate electricity. The significant advantage of the tower system is that it can achieve a higher operating temperature, thereby effectively improving the efficiency of the thermal cycle, which is crucial to improving the energy efficiency of the entire solar thermal power generation system. However, with the gradual expansion of the system scale, especially when building high-power solar thermal power stations, the tower system has also exposed some obvious limitations. Specifically, as the area of ​​the reflector field increases, the focusing efficiency of the reflector far away from the collector tower decreases significantly, resulting in a large amount of energy lost during the transmission process, which cannot meet the stringent requirements of high-power power generation. In addition, long-distance light transmission will further increase optical losses, especially for reflectors located outside the mirror field, this loss is particularly significant, thereby reducing the solar energy utilization efficiency of the entire system.

[0004] In contrast, the trough solar collector system uses a parabolic trough collector to focus sunlight into the collector tube at the focal point of the trough, transfer heat through a high-temperature working fluid (mainly thermal oil), and then drive a steam turbine to generate electricity. The advantage of the trough system is that its design is relatively simple and its optical efficiency is relatively stable, making it particularly suitable for small and medium-sized solar thermal power stations. However, the trough system has shortcomings in terms of thermal conversion efficiency, especially under high temperature conditions, where its energy loss is relatively large, making it difficult to match the high-efficiency performance of the tower system. In addition, due to its low operating temperature, the trough system is generally only suitable for small and medium-power power stations and is difficult to expand to large-scale, high-power solar thermal power generation projects.

[0005] As the global demand for renewable energy continues to grow, the market demand for large-scale, high-power solar thermal power plants is becoming increasingly urgent, especially for plants of 300MW and above. However, existing tower and trough collector systems have serious performance bottlenecks at this power level. Currently, most of the solar thermal power plants that have been put into operation are small and medium-power projects, and the maximum unit power usually does not exceed 100MW. For 300MW-class power plants, existing technologies have not yet found a successful solution in terms of thermal efficiency and system stability.

[0006] The defects of tower systems are particularly prominent in large-scale power station applications. Although the increase in the mirror field area can increase the concentrated solar power and thus support larger-scale power station installations, as the radius of the mirror field gradually increases, the distance between the heliostat and the collector tower also increases, resulting in a significant decrease in the concentration efficiency and a decrease in the mirror field's photothermal conversion efficiency. Therefore, the practice of increasing the power of a power station only by expanding the mirror field area will not only reduce the overall efficiency of the system, but also increase construction costs and reduce economic efficiency, thereby limiting the application of tower systems in high-power solar thermal systems.

[0007] In past research and practice, the trough-tower integration technology has been used in the solar-coal coupling integration system. By combining the tower solar thermal collection system with the reheat steam side of the coal-fired power generation system, and the trough solar thermal collection system with the high-pressure side of the coal-fired power generation system, effective heating integration of different parts is achieved. However, this integration method does not fundamentally solve the limitations of tower and trough systems in large-scale, high-power CSP power station applications.

[0008] Therefore, there is an urgent need to develop a new type of solar thermal power generation technology or system to overcome the shortcomings of existing tower and trough collector systems in large-scale, high-power applications and meet the market demand for efficient, stable and economical large-scale solar thermal power stations. Summary of the invention

[0009] The purpose of the present invention is to provide a high-power trough-tower coupled solar thermal power generation system to solve the problems existing in the above-mentioned prior art. The trough collector is used to heat the molten salt from low temperature to medium temperature, and then the tower collector is used to heat the molten salt coming out of the trough collector from medium temperature to high temperature, thereby realizing temperature step utilization. The high-temperature molten salt is used to generate steam through a steam generator, and then the steam is used to generate electricity through a steam turbine. The system of the present invention combines the advantages of high optical efficiency of the trough collector and high temperature of the tower collector, breaking through the performance improvement bottleneck of a single system in the construction of a high-power solar thermal power generation system.

[0010] To achieve the above object, the present invention provides the following solutions:

[0011] The present invention provides a high-power trough-tower coupled solar thermal power generation system, comprising a thermal energy storage device, a trough collector, a tower collector, a steam generator and a steam turbine, wherein the thermal energy storage device comprises a low-temperature molten salt storage tank, a medium-temperature molten salt storage tank and a high-temperature molten salt storage tank; the heat collecting pipe inlet of the trough collector is connected to the outlet of the low-temperature molten salt storage tank, and the heat collecting pipe outlet of the trough collector is connected to the inlet of the medium-temperature molten salt storage tank; the heat collecting tower inlet of the tower collector is connected to the outlet of the medium-temperature molten salt storage tank, and the heat collecting tower outlet of the tower collector is connected to the inlet of the high-temperature molten salt storage tank; the steam generator comprises a molten salt channel and a steam channel, the inlet of the molten salt channel is connected to the outlet of the high-temperature molten salt storage tank, and the outlet of the molten salt channel is connected to the inlet of the low-temperature molten salt storage tank; the steam inlet of the steam turbine is connected to the outlet of the steam channel, and the feed water outlet of the steam turbine is connected to the inlet of the steam channel.

[0012] In one embodiment, the molten salt temperature of the low-temperature molten salt storage tank is 280°C to 300°C, the molten salt temperature of the medium-temperature molten salt storage tank is 384°C to 404°C, and the molten salt temperature of the high-temperature molten salt storage tank is 555°C to 575°C.

[0013] In one embodiment, the tower collector is designed using the Monte Carlo ray method, and a tower heliostat field is formed using heliostats; the trough collectors are arranged around the tower heliostat field and are finally collected by the tower collector.

[0014] In one embodiment, the steam generator includes a first steam generator, a second steam generator and a third steam generator connected in series, the first steam generator is provided with an inlet of a molten salt channel and an outlet of a steam channel, and the third steam generator is provided with an outlet of a molten salt channel and an inlet of a steam channel.

[0015] In one embodiment, a fourth steam generator is further included. The fourth steam generator is arranged in parallel with the first steam generator, and the fourth steam generator is used to reheat the steam of the steam turbine.

[0016] In one embodiment, the steam turbine includes a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder and a regenerator. After the steam enters the high-pressure cylinder to perform work, it is reheated by the fourth steam generator and then enters the intermediate-pressure cylinder and the low-pressure cylinder in sequence to perform work. The regenerator utilizes the steam from the high-pressure cylinder, the intermediate-pressure cylinder and / or the low-pressure cylinder, and the feed water is heated by the regenerator and then enters the next cycle.

[0017] In one embodiment, the regenerator includes a four-stage low-pressure heater and a three-stage high-pressure heater, the four-stage low-pressure heater utilizes the steam of the low-pressure cylinder, and the three-stage high-pressure heater utilizes the steam of the high-pressure cylinder and the medium-pressure cylinder; the four-stage low-pressure heater includes a No. 1 low-pressure heater, a No. 2 low-pressure heater, a No. 3 low-pressure heater and a No. 4 low-pressure heater; the three-stage high-pressure heater includes a No. 1 high-pressure heater, a No. 2 high-pressure heater and a No. 3 high-pressure heater; the feed water enters the steam channel after being heated by the No. 4 low-pressure heater, the No. 3 low-pressure heater, the No. 2 low-pressure heater, the No. 1 low-pressure heater, the No. 3 high-pressure heater, the No. 2 high-pressure heater and the No. 1 high-pressure heater in sequence.

[0018] In one embodiment, the steam turbine includes a high-pressure cylinder, a low-pressure cylinder and a regenerator. After the steam enters the high-pressure cylinder to perform work, it enters the low-pressure cylinder to perform work after being reheated by the fourth steam generator. The regenerator utilizes the steam from the high-pressure cylinder and / or the low-pressure cylinder, and the feed water is heated by the regenerator and enters the next cycle.

[0019] In one embodiment, the regenerator includes a four-stage low-pressure heater and a three-stage high-pressure heater, the four-stage low-pressure heater utilizes the steam of the low-pressure cylinder, and the three-stage high-pressure heater utilizes the steam of the high-pressure cylinder and the low-pressure cylinder; the four-stage low-pressure heater includes a No. 1 low-pressure heater, a No. 2 low-pressure heater, a No. 3 low-pressure heater and a No. 4 low-pressure heater; the three-stage high-pressure heater includes a No. 1 high-pressure heater, a No. 2 high-pressure heater and a No. 3 high-pressure heater; it also includes a No. 0 high-pressure heater, and the No. 0 high-pressure heater utilizes the steam of the low-pressure cylinder; the feed water enters the steam channel after being heated by the No. 4 low-pressure heater, the No. 3 low-pressure heater, the No. 2 low-pressure heater, the No. 1 low-pressure heater, the No. 3 high-pressure heater, the No. 2 high-pressure heater, the No. 1 high-pressure heater and the No. 0 high-pressure heater in sequence.

[0020] In one embodiment, a return pipe is provided between the fourth low-pressure heater, the third low-pressure heater, the second low-pressure heater, the first low-pressure heater, the third high-pressure heater, the second high-pressure heater and the first high-pressure heater, and the return water volume of the return pipe between the third low-pressure heater and the fourth low-pressure heater is reduced or no return pipe is provided.

[0021] Compared with the prior art, the present invention has achieved the following technical effects:

[0022] The present invention is a system that uses solar thermal energy as the main body and directly uses solar thermal energy for independent power generation. The tower collector and the trough collector are no longer used separately. Instead, the trough collector is used to heat the molten salt from low temperature to medium temperature, and then the tower collector is used to heat the molten salt from the trough collector from medium temperature to high temperature, so as to achieve energy cascade utilization. The high-temperature molten salt is used to generate steam through a steam generator, and then the steam is used to generate electricity through a steam turbine. Therefore, the trough-tower coupling of the high-power trough-tower coupled solar thermal power generation system of the present invention is different from the traditional light-coal coupling system in terms of ideas and uses. The system of the present invention combines the advantages of high optical efficiency of the trough collector and high temperature of the tower collector, breaking through the performance improvement bottleneck of a single system in the construction of a high-power solar thermal power generation system.

[0023] Other technical solutions included in the present invention can also achieve the following technical effects:

[0024] The temperature of the molten salt heated in the present invention is heated from a low temperature of 280°C to 300°C to a medium temperature of 384°C to 404°C by a trough collector, and then heated to a high temperature of 555°C to 575°C by a tower collector, thereby realizing efficient temperature gradient utilization.

[0025] In addition, the tower collector is designed using the Monte Carlo ray method, and heliostats are used to form a tower heliostat field. At the same time, trough collectors are arranged around the tower heliostat field and finally converge to the tower collector, reducing the distance that the molten salt is transmitted from the trough collector to the tower collector, thereby reducing heat loss and improving the utilization efficiency of solar energy.

[0026] By optimizing the configuration of trough collectors and tower collectors, the trough-tower coupled system can effectively improve energy utilization efficiency, reduce mirror field losses, and achieve higher power generation output in 300MW-class solar thermal power stations.

[0027] The steam turbine structure of the subcritical pressure trough tower hybrid solar thermal power generation system (SCPSTP) of the present invention is relatively traditional and suitable for subcritical pressure. The seven-stage regenerative heater (regenerator) ensures the step-by-step heating of the incoming water, thereby improving the thermal efficiency of the system. The system is suitable for medium-power power stations and has high stability. The ultra-high pressure trough tower hybrid solar thermal power generation system (UHPSTP) of the present invention simplifies the steam turbine side structure, removes the medium-pressure cylinder and increases the number of regenerative heaters (regenerators), thereby achieving more efficient heat conversion between the high-pressure cylinder and the low-pressure cylinder, significantly improving the overall performance of the system, and is particularly suitable for high-power power generation scenarios. The above two systems have demonstrated their respective advantages in 300MW-level solar thermal power stations and can meet the needs of high-power power generation in different scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0029] Figure 1 It is a subcritical pressure tank tower hybrid solar thermal power generation system (SCPSTP) in an embodiment of the present invention;

[0030] Figure 2 It is an ultra-high pressure trough-tower hybrid solar thermal power generation system (UHPSTP) in an embodiment of the present invention;

[0031] Among them, 1. Trough collector; 2. Tower collector; 3. Thermal energy storage device; 4. Steam generator; 5. Steam turbine; 6. High-pressure heater; 7. Low-pressure heater; 8. Condenser; 9. Deaerator;

[0032] 11. Grooved lens; 12. Heat collecting tube;

[0033] 21. Tower lens; 22. Heat collecting tower;

[0034] 31. Low-temperature molten salt storage tank; 32. Medium-temperature molten salt storage tank; 33. High-temperature molten salt storage tank;

[0035] 41. a first steam generator; 42. a second steam generator; 43. a third steam generator;

[0036] 51. High-pressure cylinder; 52. Medium-pressure cylinder; 53. Low-pressure cylinder;

[0037] 61. No. 1 high-voltage heater; 62. No. 2 high-voltage heater; 63. No. 3 high-voltage heater; 64. No. 0 high-voltage heater;

[0038] 71. No. 1 low-pressure heater; 72. No. 2 low-pressure heater; 73. No. 3 low-pressure heater; 74. No. 4 low-pressure heater;

[0039] S (including S1 and S2), steam; R (including R1), reheated steam; M (including M1, M2, M3, M4), molten salt; F (including F1 and F2), feed water. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0041] The purpose of the present invention is to provide a high-power trough-tower coupled solar thermal power generation system to solve the problems existing in the prior art. The trough collector is used to heat the molten salt from low temperature to medium temperature, and then the tower collector is used to heat the molten salt coming out of the trough collector from medium temperature to high temperature, thereby realizing temperature step utilization. The high-temperature molten salt is used to generate steam through a steam generator, and then the steam is used to generate electricity through a steam turbine. The system of the present invention combines the advantages of high optical efficiency of the trough collector and high temperature of the tower collector, breaking through the performance improvement bottleneck of a single system in the construction of a high-power solar thermal power generation system.

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] The "high power level" referred to in the present invention refers to 100MW and above, especially 300MW and above.

[0044] like Figure 1 and Figure 2As shown, the present invention provides a high-power trough-tower coupled solar thermal power generation system, including a thermal energy storage device 3, a trough collector 1, a tower collector 2, a steam generator 4 and a steam turbine 5. The thermal energy storage device 3 includes a low-temperature molten salt storage tank 31, a medium-temperature molten salt storage tank 32 and a high-temperature molten salt storage tank 33. Each molten salt storage tank is used to store molten salts of different temperatures, which circulate under the action of a molten salt circulation pump to achieve a step-by-step gradient heating method. The trough collector 1 includes a trough lens 11 and a heat collecting tube 12. The trough lens 11 uses a trough parabolic reflector to track the position of the sun through a single-axis or dual-axis tracking system, and reflects the solar tube to the heat collecting tube 12 to heat the molten salt in the heat collecting tube 12. The inlet of the heat collecting pipe 12 is connected to the outlet of the low-temperature molten salt storage tank 31, and the outlet of the heat collecting pipe 12 is connected to the inlet of the medium-temperature molten salt storage tank 32. The low-temperature molten salt flowing out of the low-temperature molten salt storage tank 31 is heated by the trough collector 1 to be medium-temperature molten salt, and enters the medium-temperature molten salt storage tank 32. The tower collector 2 includes a tower lens 21 and a heat collecting tower 22. The tower lens 21 uses a plurality of plane reflectors (heliostats), tracks the position of the sun through a dual-axis tracking system, and reflects sunlight onto the heat collecting tower 22 to heat the molten salt in the heat collecting tower 22. The inlet of the heat collecting tower 22 is connected to the outlet of the medium-temperature molten salt storage tank 32, and the outlet of the heat collecting tower 22 is connected to the inlet of the high-temperature molten salt storage tank 33. The medium-temperature molten salt flowing out of the medium-temperature molten salt storage tank 32 is heated by the tower collector 2 to be high-temperature molten salt, and enters the high-temperature molten salt storage tank 33. The steam generator 4 includes a molten salt channel and a steam channel. In the steam generator 4, the high-temperature molten salt and the feed water are heat exchanged, and the feed water is converted into superheated steam to drive the steam turbine 5 to generate electricity. The molten salt channel is used to circulate the molten salt in the thermal energy storage device 3, and the steam channel is used to circulate the steam generated to supply the steam turbine 5. The inlet of the molten salt channel is connected to the outlet of the high-temperature molten salt storage tank 33, and the outlet of the molten salt channel is connected to the inlet of the low-temperature molten salt storage tank 31. The molten salt flowing out of the thermal energy storage device 3 returns to the thermal energy storage device 3 for further heating after heat exchange in the steam generator 4. The steam turbine 5 is provided with a steam inlet and a feed water outlet. The steam inlet is connected to the outlet of the steam channel of the steam generator 4, and the feed water outlet is connected to the inlet of the steam channel. After the steam enters the steam turbine 5 to perform work, it is condensed by the condenser 8 and flows out from the feed water outlet. The feed water generates steam after passing through the steam generator 4. In this cycle, the steam turbine 5 uses steam to generate electricity.

[0045] As can be seen from the above content, the present invention is a system that uses solar thermal energy as the main body and directly uses solar thermal energy for independent power generation, wherein the tower collector 2 and the trough collector 1 are no longer used separately, but according to the respective defects of the tower collector 2 and the trough collector 1 in the application of pure solar thermal high-power power generation system, the trough collector 1 is used to heat the molten salt from low temperature to medium temperature, and then the tower collector 2 is used to heat the molten salt from the trough collector 1 from medium temperature to high temperature, so as to realize the temperature step utilization, and the high-temperature molten salt is used to generate steam through the steam generator 4, and then the steam is used to generate electricity through the steam turbine 5. Therefore, the trough-tower coupling of the high-power trough-tower coupled solar thermal power generation system of the present invention is different from the traditional light-coal coupling system in terms of ideas and uses. The system of the present invention combines the advantages of high optical efficiency of the trough collector 1 and the advantages of high-temperature operation of the tower collector 2, breaking through the performance bottleneck of a single system in the construction of a high-power solar thermal power generation system.

[0046] In one embodiment, the molten salt temperature of the low-temperature molten salt storage tank 31 is 280°C to 300°C, the molten salt temperature of the medium-temperature molten salt storage tank 32 is 384°C to 404°C, and the molten salt temperature of the high-temperature molten salt storage tank 33 is 555°C to 575°C, so as to achieve temperature gradient utilization. In a specific embodiment, the trough collector 1 can be used to preheat the molten salt, raising the temperature of the molten salt from 290°C to 394°C, and then entering the tower collector 2 to be further heated to 565°C.

[0047] In one embodiment, the tower collector 2 is designed using the Monte Carlo ray method, and heliostats are used to form a tower heliostat field; the trough collector 1 is arranged around the tower heliostat field and finally collected to the tower collector 2. In a specific embodiment, the tower heliostat is selected to be 120m in size. 2 , designed by Monte Carlo ray method, bionic spiral layout, using 8950 heliostats to form a tower heliostat field; the incident angle of the trough collector 1 is 38.02°, the single length is 135m, a total of 135 columns, each column uses four trough collectors 1, and the east-west arrangement is adopted. The overall layout adopts the arrangement of the trough collector 1 around the tower heliostat field, and the 135 columns are divided into four parts and placed in the east, west, south and north directions of the tower heliostat field, and finally converged to the tower collector 2 to reduce the distance of the molten salt from the trough collector 1 to the tower collector 2. By optimizing the configuration of the trough collector 1 and the tower collector 2, the trough-tower coupled system of the present invention can effectively improve the energy utilization efficiency, reduce the mirror field loss, and achieve higher power generation output in a 300MW-level solar thermal power station. In this example, the main parameters of the solar field subsystem and the thermal energy storage device 3 are shown in Table 1.

[0048] Table 1 Main parameters of solar field subsystem and thermal energy storage device

[0049] Main parameters unit Design value DNI <![CDATA[W / m 2 ]]> 850 Molten salt mass flow t / h 6298.175 Reheating molten salt mass flow t / h 1259.635 Single heliostat area <![CDATA[m 2 ]]> 120 Number of heliostats pieces 8950 Length of single trough collector M 135 High temperature molten salt storage tank temperature ℃ 565 Medium temperature molten salt storage tank temperature ℃ 394 Low temperature molten salt storage tank temperature ℃ 296 Total solar radiation energy MW 1560.9 Total energy of soda MW 712.912

[0050] In Table 1, DNI is normal direct radiation / radiant illuminance.

[0051] In one embodiment, the steam generator 4 includes a first steam generator 41, a second steam generator 42 and a third steam generator 43 connected in series, the first steam generator 41 is provided with an inlet of a molten salt channel and an outlet of a steam channel, and the third steam generator 43 is provided with an outlet of a molten salt channel and an inlet of a steam channel. The high-temperature molten salt flows through the first steam generator 41, the second steam generator 42 and the third steam generator 43 in sequence, and then cools down to become a low-temperature molten salt and flows out to the low-temperature molten salt storage tank 31. The feed water passes through the third steam generator 43, the second steam generator 42 and the first steam generator 41 in sequence and becomes steam and flows out to the steam turbine 5. The steam generator 4 adopts a multi-stage heating method, which can gradually heat the feed water to superheated steam, drive the steam turbine 5 to generate electricity, and ensure heating efficiency.

[0052] In one embodiment, a fourth steam generator 44 is further included. The fourth steam generator 44 is arranged in parallel with the first steam generator 41. The fourth steam generator 44 is used to reheat the steam of the steam turbine 5 to ensure the steam temperature requirement of the steam turbine 5 and ensure the efficient and smooth operation of the steam turbine 5.

[0053] In one embodiment, if Figure 1 As shown, a subcritical pressure tank tower hybrid solar thermal power generation system (SCPSTP) is used. The subcritical pressure refers to the steam pressure of about 16MPa. For example, the molten salt from the high-temperature molten salt storage tank 33 enters the steam generator 4 to exchange heat with the feed water, and the feed water is heated to 16.7MPa superheated steam and enters the steam turbine 5 to do work. In this example, the steam turbine 5 includes a high-pressure cylinder 51, a medium-pressure cylinder 52, a low-pressure cylinder 53 and a regenerator. After the steam enters the high-pressure cylinder 51 to do work, it is reheated by the fourth steam generator 44 and then enters the medium-pressure cylinder 52 and the low-pressure cylinder 53 to do work and generate electricity. The regenerator uses the steam of the high-pressure cylinder 51, the medium-pressure cylinder 52 and / or the low-pressure cylinder 53. The feed water flowing out of the condenser 8 is heated by the regenerator and enters the next cycle. The feed water is preheated by the application of the regenerator, which improves the utilization efficiency of the molten salt temperature and the steam generation efficiency. Due to the use of subcritical pressure, the system performs well in stability and safety, and is suitable for large-scale solar thermal power stations.

[0054] In one embodiment, if Figure 1As shown, the regenerator includes a four-stage low-pressure heater 7 and a three-stage high-pressure heater 6. A deaerator 9 is also provided between the low-pressure heater 7 and the high-pressure heater 6. The deaerator 9 can not only prevent oxidation corrosion and improve steam quality, but also balance water volume and water temperature, and achieve energy saving and environmental protection. The four-stage low-pressure heater 7 includes a No. 1 low-pressure heater 71, a No. 2 low-pressure heater 72, a No. 3 low-pressure heater 73, and a No. 4 low-pressure heater 74. The three-stage high-pressure heater 6 includes a No. 1 high-pressure heater 61, a No. 2 high-pressure heater 62, and a No. 3 high-pressure heater 63. The four-stage low-pressure heater 7 uses the steam of the low-pressure cylinder 53, and the three-stage high-pressure heater 6 uses the steam of the high-pressure cylinder 51 and the medium-pressure cylinder 52 (wherein, the No. 1 high-pressure heater 61 and the No. 2 high-pressure heater 62 use the steam of the high-pressure cylinder 51, and the No. 3 high-pressure heater 63 uses the steam of the medium-pressure cylinder 52). The feed water enters the steam channel of the steam generator 4 after being heated by the No. 4 low-pressure heater 74, the No. 3 low-pressure heater 73, the No. 2 low-pressure heater 72, the No. 1 low-pressure heater 71, the No. 3 high-pressure heater 63, the No. 2 high-pressure heater 62 and the No. 1 high-pressure heater 61 in sequence. In this example, the regenerator is divided into seven stages, and part of the extraction steam is used to heat the feed water to ensure that the feed water maintains efficient heat exchange when entering the steam generator 4. The outlet temperature of the feed water heated by the regenerator is related to the low-temperature molten salt storage tank 31. The outlet temperature should be between 245°C and 250°C to ensure that the temperature of the molten salt will not be too low after heat exchange with the preheated feed water, resulting in solidification. The temperature of the molten salt entering the low-temperature molten salt storage tank 31 is about 296°C. In this example, the steam turbine 5 adopts a high-pressure-medium-pressure-low-pressure structure, combined with the regenerator of the seven-stage regenerative heating system, and the inlet water temperature is increased by heating step by step, thereby improving the thermal efficiency of the entire system.

[0055] like Figure 1As shown, the process of the subcritical pressure tank tower hybrid solar thermal power generation system is that the molten salt M4 comes out of the high-temperature molten salt storage tank 33 and enters the steam generator 4 (the first steam generator 41, the second steam generator 42 and the third steam generator 43) to exchange heat with the feed water to produce steam S1. After the steam S1 enters the high-pressure cylinder 51 to do work, it enters the fourth steam generator 44 for reheating. The reheated steam R1 enters the medium-pressure cylinder 52. The steam S2 after doing work enters the low-pressure cylinder 53 to do work, and then condenses through the condenser 8. Then the feed water F1 passes through the low-pressure heater 7 (the fourth low-pressure heater 74, the third low-pressure heater 73, the second low-pressure heater 72 and the first low-pressure heater 71), the deaerator 9, and the high-pressure heater 6 (the third high-pressure heater 63, the second high-pressure heater 62, and the first high-pressure heater 61) to heat exchange with the extraction steam to raise the temperature to about 245°C, and enter the next cycle of heat exchange. After passing through the steam generator 4, the temperature of the molten salt drops to 296°C and enters the low-temperature molten salt storage tank 31. The molten salt M1 in the low-temperature molten salt storage tank 31 is pumped into the trough collector 1 for heat exchange by the molten salt pump. After the temperature rises to 394°C, it enters the medium-temperature molten salt storage tank 32 for transition, and then enters the tower collector 2 for heat exchange. After the temperature rises to 565°C, it enters the high-temperature molten salt storage tank 33 to enter the next cycle.

[0056] In one embodiment, if Figure 1As shown, the inlet and outlet pressures of the feed water of the No. 4 low-pressure heater 74 are 0.897MPa and 0.887MPa, and the inlet and outlet temperatures are 45.321℃ and 56.507℃ respectively; the inlet and outlet pressures of the feed water of the No. 3 low-pressure heater 73 are 0.887MPa and 0.877MPa, and the inlet and outlet temperatures are 56.507℃ and 59.945℃ respectively; the inlet and outlet pressures of the feed water of the No. 2 low-pressure heater 72 are 0.877MPa and 0.867MPa, and the inlet and outlet temperatures are 59.945℃ and 79.91℃ respectively; the inlet and outlet pressures of the feed water of the No. 1 low-pressure heater 71 are 0.867MPa and 0.857MPa, and the inlet and outlet temperatures are 79.91℃ and 102.782℃ respectively. The inlet and outlet pressures of the feed water of the deaerator 9 are 0.857MPa and 16.74MPa, and the inlet and outlet temperatures are 102.782℃ and 177.97℃. The feedwater inlet and outlet pressures of the No. 3 high-pressure heater 63 are 16.74MPa and 16.73MPa, and the inlet and outlet temperatures are 177.97℃ and 194.873℃; the feedwater inlet and outlet pressures of the No. 2 high-pressure heater 62 are 16.73MPa and 16.72MPa, and the inlet and outlet temperatures are 194.873℃ and 238.319℃; the feedwater inlet and outlet pressures of the No. 1 high-pressure heater 61 are 16.72MPa and 16.71MPa, and the inlet and outlet temperatures are 238.319℃ and 247.45℃. The feedwater outlet temperature of the No. 1 high-pressure heater 61 is 247.45℃, that is, the feedwater outlet temperature is between 245℃ and 250℃, thereby realizing safe and stable heat exchange of molten salt. In this example, the main parameters of the steam turbine side of the SCPSTP unit are shown in Table 2.

[0057] Table 2 Main parameters of steam turbine side of SCPSTP unit

[0058]

[0059]

[0060] In Table 2, HP is the high-pressure cylinder 51, IP is the medium-pressure cylinder 52, and LP is the low-pressure cylinder 53.

[0061] In one embodiment, if Figure 2As shown, an ultra-high pressure tank tower hybrid solar thermal power generation system (UHPSTP) is used. Ultra-high pressure means that the pressure of steam is about 13MPa. In this example, the steam turbine 5 includes a high-pressure cylinder 51, a low-pressure cylinder 53 and a regenerator. After the steam enters the high-pressure cylinder 51 to do work, it enters the low-pressure cylinder 53 to do work after being reheated by the fourth steam generator 44 to generate electricity. The regenerator uses the steam of the high-pressure cylinder 51 and / or the low-pressure cylinder 53. The feed water flowing out of the condenser 8 enters the next cycle after being heated by the regenerator. The feed water is preheated by the application of the regenerator, which improves the utilization efficiency of the molten salt temperature and the steam generation efficiency. The ultra-high pressure tank tower hybrid solar thermal power generation system is similar in structure to the subcritical pressure tank tower hybrid solar thermal power generation system, but it has been significantly optimized on the steam turbine 5 side, and the medium-pressure cylinder 52 has been removed. The system simplifies the structure, achieves higher steam utilization and thermal efficiency, and further improves energy utilization by optimizing the regeneration heating process (regenerator). Compared with the subcritical pressure trough-tower hybrid solar thermal power generation system, the ultra-high pressure trough-tower hybrid solar thermal power generation system performs better in power generation power and efficiency, and is suitable for larger-scale solar thermal power stations.

[0062] In one embodiment, if Figure 2 As shown, the regenerator includes a four-stage low-pressure heater 7 and a three-stage high-pressure heater 6. A deaerator 9 is also provided between the low-pressure heater 7 and the high-pressure heater 6. The deaerator 9 can not only prevent oxidation corrosion and improve steam quality, but also balance water volume and water temperature, and achieve energy saving and environmental protection. The four-stage low-pressure heater 7 includes a No. 1 low-pressure heater 71, a No. 2 low-pressure heater 72, a No. 3 low-pressure heater 73, and a No. 4 low-pressure heater 74. The three-stage high-pressure heater 6 includes a No. 1 high-pressure heater 61, a No. 2 high-pressure heater 62, and a No. 3 high-pressure heater 63. It also includes a No. 0 high-pressure heater 64, which uses the steam of the low-pressure cylinder 53; the four-stage low-pressure heater 7 uses the steam of the low-pressure cylinder 53, and the three-stage high-pressure heater 6 uses the steam of the high-pressure cylinder 51 and the low-pressure cylinder 53 (wherein, the No. 1 high-pressure heater 61 and the No. 2 high-pressure heater 62 use the steam of the high-pressure cylinder 51, and the No. 3 high-pressure heater 63 uses the steam of the low-pressure cylinder 53). The feed water is heated by the No. 4 low-pressure heater 74, the No. 3 low-pressure heater 73, the No. 2 low-pressure heater 72, the No. 1 low-pressure heater 71, the No. 3 high-pressure heater 63, the No. 2 high-pressure heater 62, the No. 1 high-pressure heater 61 and the No. 0 high-pressure heater 64 in sequence and then enters the steam channel of the steam generator 4. In this example, the steam turbine 5 side is only composed of the high-pressure cylinder 51 and the low-pressure cylinder 53, and cooperates with the regenerator of the eight-stage regenerative heating system to further improve the heat exchange efficiency and the overall thermal power efficiency of the system.

[0063] In one embodiment, if Figure 2As shown, the No. 4 low-pressure heater 74, the No. 3 low-pressure heater 73, the No. 2 low-pressure heater 72, the No. 1 low-pressure heater 71, the No. 3 high-pressure heater 63, the No. 2 high-pressure heater 62 and the No. 1 high-pressure heater 61 are provided with a return pipe between the latter stage and the former stage, and the return water volume of the return pipe between the No. 3 low-pressure heater 73 and the No. 4 low-pressure heater 74 is reduced or no return pipe is provided, thereby reducing the steam extraction volume of the No. 4 low-pressure heater 74, and at the same time, the steam extraction volume of the No. 1 low-pressure heater 71 and the No. 2 low-pressure heater 72 can be increased, thereby further improving the feed water temperature and avoiding the occurrence of molten salt solidification due to too low feed water temperature.

[0064] like Figure 2 The difference between the process of the ultra-high pressure trough-tower hybrid solar thermal power generation system shown and the process of the subcritical pressure trough-tower hybrid solar thermal power generation system is that the reheated steam R1 directly enters the low pressure cylinder 53 to do work, and the temperature of the feed water F1 is 225°C after passing through the high pressure heater 6 (No. 3 high pressure heater 63, No. 2 high pressure heater 62 and No. 1 high pressure heater 61), and it needs to pass through the No. 0 high pressure heater 64 to be heated to about 245°C.

[0065] In one embodiment, if Figure 2As shown, the regenerator adopts eight stages, the inlet and outlet pressures of the No. 4 low-pressure heater 74 are 1.058MPa and 1.048MPa, and the inlet and outlet temperatures are 45.884℃ and 79.016℃; the inlet and outlet pressures of the No. 3 low-pressure heater 73 are 1.048MPa and 1.043MPa, and the inlet and outlet temperatures are 79.016℃ and 104.739℃; the inlet and outlet pressures of the No. 2 low-pressure heater 72 are 1.043MPa and 1.033MPa, and the inlet and outlet temperatures are 104.739℃ and 128.178℃; the inlet and outlet pressures of the No. 1 low-pressure heater 71 are 1.033MPa and 1.023MPa, and the inlet and outlet temperatures are 128.178℃ and 149.814℃. The inlet and outlet pressures of the deaerator 9 are 1.023MPa and 14.045MPa, and the inlet and outlet temperatures are 149.814℃ and 183.256℃. The inlet and outlet pressures of the No. 3 high-pressure heater 63 are 14.045MPa and 14.035MPa, and the inlet and outlet temperatures are 183.256℃ and 209.194℃; the inlet and outlet pressures of the No. 2 high-pressure heater 62 are 14.035MPa and 14.025MPa, and the inlet and outlet temperatures are 209.194℃ and 230.063℃; the inlet and outlet pressures of the No. 1 high-pressure heater 61 are 14.025MPa and 14.015MPa, and the inlet and outlet temperatures are 230.063℃ and 241.713℃. The temperature of the feed water coming out of the No. 1 high-pressure heater 61 is 241.713°C. In order to ensure that the temperature of the feed water entering the third steam generator 43 and exchanging heat with the molten salt is between 245°C and 250°C, a No. 0 high-pressure heater 64 is added. A portion of steam is extracted from the first-stage steam extraction of the low-pressure cylinder 53 to heat the feed water to ensure stable heat exchange in the subsequent steam generator 4. The feed water inlet and outlet pressures of the No. 0 high-pressure heater 64 are 14.015MPa and 14.01MPa, and the inlet and outlet temperatures are 241.713°C and 247.431°C. By raising the feed water temperature to a suitable temperature of about 250°C, the molten salt temperature entering the low-temperature molten salt storage tank 31 is ensured to be around 296°C, and the steam has reached the optimal temperature before entering the high-pressure cylinder 51, reducing the heat loss of the system and improving the overall efficiency. In this example, the main parameters of the UHPSTP steam turbine side are shown in Table 3.

[0066] Table 3 Main parameters of UHPSTP steam turbine side

[0067] Main parameters unit Design value HP / LP inlet temperature ℃ 550 / 550 HP / LP Inlet Pressure MPa 13.7 / 2.795 Main steam mass flow t / h 887.587 Reheat steam mass flow t / h 825.851 HP Extraction Steam Pressure MPa 3.643 / 2.8871.935 Deaerator steam inlet pressure MPa 1.023 Low pressure extraction steam pressure MPa 0.526 / 0.286 / 0.134 / 0.052 Feed water temperature ℃ 247.431 power MW 327.369

[0068] In Table 3, HP is the high-pressure cylinder 51 , and LP is the low-pressure cylinder 53 .

[0069] The present invention proposes a 300MW-class trough-tower coupled solar thermal power generation system, which breaks through the bottleneck of the existing technology in high-power solar thermal power stations. In particular, based on the tower collector 2, the organic combination of the trough collector 1 and the tower collector 2 significantly improves the thermoelectric conversion efficiency of the overall system. The innovation and advantages of this technology are mainly reflected in the following aspects:

[0070] 1. Innovation of high-power CSP plants

[0071] Most of the existing solar thermal power stations are concentrated in the field of small and medium power, and the maximum unit power usually does not exceed 100MW. The high-power level trough tower coupled solar thermal power generation system proposed in this invention effectively solves the technical challenges faced by existing small and medium power solar thermal power stations when expanding to large-scale power stations, and realizes a 300MW-level high-power solar thermal power generation system for the first time.

[0072] Breaking through the limitations of existing technologies: Traditional tower systems or trough systems have large energy losses and low efficiency in large-scale power generation applications, making it difficult to expand to the 300MW level. The present invention not only achieves stable power output under high-power conditions through the trough-tower coupling method, but also greatly improves the thermal power efficiency, making it suitable for the future energy market's demand for efficient, clean, and sustainable power generation.

[0073] Scalability of system scale: Compared with traditional small and medium-sized CSP power stations, the improvement in power level of the system of the present invention means that it can be used as a green energy power generation solution to replace traditional thermal power stations and meet the needs of modern power grids for high-power, low-emission power sources.

[0074] In the process of system design, considering that the circulation pressure of the supercritical unit is too high, resulting in too high overall parameters, it is almost difficult to reduce the feed water temperature to between 245℃ and 250℃, so subcritical and ultra-high pressure systems are proposed. The SCPSTP system can achieve stable operation of high-power solar thermal power generation, and has better performance in continuity and stability, while the UHPSTP system is more efficient than the SCPSTP system. The photovoltaic efficiency and thermal efficiency of the SCPSTP system are 20.44% and 44.76% respectively, while the photovoltaic efficiency and thermal efficiency of the UHPSTP system are 20.97% and 45.92% respectively, which are increased by 0.53% and 1.24% respectively. In future engineering practice, suitable systems can be selected according to different geographical locations and different climatic conditions, so that they can be used in various situations.

[0075] 2. Efficiency improvement of the trough-tower coupling system

[0076] The high-power level trough tower coupled solar thermal power generation system proposed by the present invention realizes the direct use of the trough tower coupled solar thermal system for power generation by optimizing the combination of the tower collector 2 and the trough collector 1, which greatly reduces the area of ​​the tower heliostat field. It can be seen from Table 1 that the number of heliostats required by the system is 8950, which is far less than the at least 15,000 heliostats in the past. And it is not the trough tower coupling in the past light-coal coupling, which is only used to assist the temperature rise of various parts of the traditional thermal power unit. In addition, thermal oil was used in the trough system in the past. In the trough tower system, it is necessary to exchange heat between the thermal oil and molten salt, and the extra heat exchanger greatly reduces the overall efficiency. The system of the present invention directly uses molten salt to enter the trough collector 1 for heat exchange, eliminating the heat exchanger required for heat exchange between thermal oil and molten salt, significantly improving the overall utilization efficiency of solar energy, especially in large-scale mirror fields, solving the problem of low efficiency of tower collector 2 in long-distance mirror fields.

[0077] Solve the problem of low efficiency of the tower collector 2: In large-scale applications of tower collector 2, as the mirror field area increases, the efficiency of the mirror field far away from the tower decreases significantly, resulting in serious energy loss. However, the trough collector 1 can collect solar energy more efficiently in the area far away from the tower and transfer it to the tower collector 2 through the molten salt system, thereby improving the overall utilization of solar energy.

[0078] Improve the efficiency of thermoelectric conversion: Under the same solar energy input conditions, the trough-tower hybrid system realizes the temperature gradient utilization, fully utilizing the respective advantages of the trough collector 1 and the tower collector 2. The trough collector 1 completes the temperature rise of the molten salt from 290°C to 394°C, and the tower collector 2 completes the temperature rise of the molten salt from 394°C to 565°C. The solar energy to electric energy conversion efficiency of the system of the present invention is significantly improved compared with the pure tower system. This shows that the advantages of the trough-tower coupling system in high-power solar thermal power generation are very obvious.

[0079] Reduce heat loss: directly use molten salt to enter the trough collector 1 for heat collection without using heat transfer oil, which reduces the use of heat exchangers between heat transfer oil and molten salt and reduces heat loss. The process of preheating molten salt significantly reduces the heat energy loss caused by long-distance transmission in the tower collector 2. Through the efficient heat transfer and energy storage of the molten salt system, it is ensured that the high-temperature molten salt can fully utilize the solar energy after entering the tower collector 2, further improving the overall performance of the system.

[0080] 3. Key breakthroughs in sustainable energy

[0081] This invention not only proposes an innovative high-power solar thermal power station solution at the technical level, but also takes a key step in the utilization of sustainable energy. Through the application of the trough-tower hybrid system, it can not only significantly reduce the dependence on fossil fuels, but also improve the efficiency of solar energy utilization and reduce carbon emissions, providing a new technical path for the future clean energy transformation.

[0082] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A high-power trough-tower coupled solar thermal power generation system, characterized in that: include: A thermal energy storage device, the thermal energy storage device comprising a low-temperature molten salt storage tank, a medium-temperature molten salt storage tank and a high-temperature molten salt storage tank; A trough collector, wherein the heat collecting pipe inlet of the trough collector is connected to the outlet of the low-temperature molten salt storage tank, and the heat collecting pipe outlet of the trough collector is connected to the inlet of the medium-temperature molten salt storage tank; A tower collector, wherein the heat collecting tower inlet of the tower collector is connected to the outlet of the medium-temperature molten salt storage tank, and the heat collecting tower outlet of the tower collector is connected to the inlet of the high-temperature molten salt storage tank; A steam generator, the steam generator comprising a molten salt channel and a steam channel, the inlet of the molten salt channel is connected to the outlet of the high-temperature molten salt storage tank, and the outlet of the molten salt channel is connected to the inlet of the low-temperature molten salt storage tank; and a steam turbine, wherein a steam inlet of the steam turbine is connected to an outlet of the steam passage, and a feed water outlet of the steam turbine is connected to an inlet of the steam passage.

2. The high-power trough-tower coupled solar thermal power generation system according to claim 1 is characterized in that: The molten salt temperature of the low-temperature molten salt storage tank is 280°C to 300°C, the molten salt temperature of the medium-temperature molten salt storage tank is 384°C to 404°C, and the molten salt temperature of the high-temperature molten salt storage tank is 555°C to 575°C.

3. The high-power trough-tower coupled solar thermal power generation system according to claim 1 is characterized in that: The tower collector is designed by using the Monte Carlo ray method, and a tower heliostat field is formed by using heliostats; the trough collector is arranged around the tower heliostat field and finally collected to the tower collector.

4. The high-power trough-tower coupled solar thermal power generation system according to any one of claims 1 to 3, characterized in that: The steam generator includes a first steam generator, a second steam generator and a third steam generator connected in series, the first steam generator is provided with an inlet of a molten salt channel and an outlet of a steam channel, and the third steam generator is provided with an outlet of a molten salt channel and an inlet of a steam channel.

5. The high-power trough-tower coupled solar thermal power generation system according to claim 4 is characterized in that: It also includes a fourth steam generator, which is arranged in parallel with the first steam generator and is used to reheat the steam of the steam turbine.

6. The high-power trough-tower coupled solar thermal power generation system according to claim 5 is characterized in that: The steam turbine includes a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder and a regenerator. After the steam enters the high-pressure cylinder to perform work, it is reheated by the fourth steam generator and then enters the intermediate-pressure cylinder and the low-pressure cylinder in sequence to perform work. The regenerator utilizes the steam from the high-pressure cylinder, the intermediate-pressure cylinder and / or the low-pressure cylinder, and the feed water is heated by the regenerator and then enters the next cycle.

7. The high-power trough-tower coupled solar thermal power generation system according to claim 6 is characterized in that: The regenerator includes a four-stage low-pressure heater and a three-stage high-pressure heater. The four-stage low-pressure heater utilizes the steam of the low-pressure cylinder, and the three-stage high-pressure heater utilizes the steam of the high-pressure cylinder and the medium-pressure cylinder; the four-stage low-pressure heater includes a No. 1 low-pressure heater, a No. 2 low-pressure heater, a No. 3 low-pressure heater and a No. 4 low-pressure heater; the three-stage high-pressure heater includes a No. 1 high-pressure heater, a No. 2 high-pressure heater and a No. 3 high-pressure heater; the feed water enters the steam channel after being heated by the No. 4 low-pressure heater, the No. 3 low-pressure heater, the No. 2 low-pressure heater, the No. 1 low-pressure heater, the No. 3 high-pressure heater, the No. 2 high-pressure heater and the No. 1 high-pressure heater in sequence.

8. The high-power trough-tower coupled solar thermal power generation system according to claim 5 is characterized in that: The steam turbine includes a high-pressure cylinder, a low-pressure cylinder and a regenerator. After the steam enters the high-pressure cylinder to perform work, it enters the low-pressure cylinder to perform work after being reheated by the fourth steam generator. The regenerator utilizes the steam from the high-pressure cylinder and / or the low-pressure cylinder, and the feed water is heated by the regenerator and enters the next cycle.

9. The high-power trough-tower coupled solar thermal power generation system according to claim 8 is characterized in that: The regenerator includes a four-stage low-pressure heater and a three-stage high-pressure heater. The four-stage low-pressure heater utilizes the steam of the low-pressure cylinder, and the three-stage high-pressure heater utilizes the steam of the high-pressure cylinder and the low-pressure cylinder; the four-stage low-pressure heater includes a No. 1 low-pressure heater, a No. 2 low-pressure heater, a No. 3 low-pressure heater and a No. 4 low-pressure heater; the three-stage high-pressure heater includes a No. 1 high-pressure heater, a No. 2 high-pressure heater and a No. 3 high-pressure heater; it also includes a No. 0 high-pressure heater, and the No. 0 high-pressure heater utilizes the steam of the low-pressure cylinder; the feed water enters the steam channel after being heated by the No. 4 low-pressure heater, the No. 3 low-pressure heater, the No. 2 low-pressure heater, the No. 1 low-pressure heater, the No. 3 high-pressure heater, the No. 2 high-pressure heater, the No. 1 high-pressure heater and the No. 0 high-pressure heater in sequence.

10. The high-power trough-tower coupled solar thermal power generation system according to claim 9 is characterized in that: The No. 4 low-pressure heater, the No. 3 low-pressure heater, the No. 2 low-pressure heater, the No. 1 low-pressure heater, the No. 3 high-pressure heater, the No. 2 high-pressure heater and the No. 1 high-pressure heater are provided with return pipes between the latter stage and the former stage, and the return water volume of the return pipe between the No. 3 low-pressure heater and the No. 4 low-pressure heater is reduced or no return pipe is provided.

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