System and method for recycling, storing and utilizing heat of photo-thermal power generation project

Abstract

The invention discloses a heat recovery, storage and utilization system and method for a photo-thermal power generation project, and belongs to the technical field of photo-thermal power generation energy storage. The heat recovery, storage and utilization system comprises a steam turbine main steam system, a reheat steam system, a high-low pressure bypass system, a high-exhaust ventilation system, a drainage system, a heat exchanger and a heat accumulator; the heat exchanger is respectively connected with the high-exhaust ventilation system, the high-low pressure bypass system and the drainage system; the heat exchanger is also connected with a condenser or a steam exhaust device; the heat accumulator is connected with the heat exchanger through a heating pipeline and a water return pipeline; and the heat accumulator is connected with a heating device. According to the system, heat discharged into the condenser or the steam exhaust device through the high-low pressure bypass system, the drainage system and the high-exhaust ventilation system in the frequent starting and stopping process of the photo-thermal unit is recycled and stored, and the heat stored in the heat accumulator can be directly used as a heating heat source of a photo-thermal power plant factory building and can also be provided for other heat users; and the heat loss in the frequent start-stop process of the photo-thermal unit is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of solar thermal power generation and energy storage technology, and in particular to a system and method for heat recovery, storage and utilization in a solar thermal power generation project. Background Art

[0002] Solar thermal power generation is a technology that uses solar thermal energy to generate electricity by collecting solar thermal energy and converting it into electricity. There are three main types of solar thermal power generation: trough system, tower system and dish system. These systems collect solar thermal energy in different ways and convert it into electricity. The biggest advantage of solar thermal power generation is that the power output is stable, which can be used for basic power and peak load regulation; in addition, its mature and reliable energy storage (heat storage) configuration can continuously generate electricity at night.

[0003] In recent years, the installed capacity of new energy power generation such as photovoltaic and wind power has grown rapidly. While helping the green and low-carbon transformation of energy, it also poses great challenges to the stable operation of the power system due to its obvious volatility, randomness and intermittent characteristics, and the peak load regulation of the power grid faces great pressure. At night, when photovoltaic power does not generate electricity, supporting construction of solar thermal energy storage power generation can solve the problem of nighttime Internet access. Solar energy is stored in molten salt tanks during the day, and the molten salt tanks release heat at night to heat steam and drive steam turbines to generate electricity. This supporting operation mode involves the problem of frequent start and stop of steam turbines. During the start-up and load reduction shutdown of the steam turbine, the high and low pressure bypass valves are opened, and the steam is discharged to the exhaust device or condenser through the bypass system; the steam traps on the turbine body, main steam system, reheat steam system, and extraction system are opened, and the water is drained to the exhaust device or condenser; during the speed increase stage of the steam turbine with load, when the high-pressure cylinder blast high exhaust temperature rises to the set value, the high-exhaust ventilation valve opens to relieve pressure and cool down the high-temperature steam, and the high-temperature steam is discharged into the condenser or exhaust device after being cooled by the high-exhaust ventilation valve and the desuperheater. Whether it is the steam discharged from the bypass and ventilation valve, or the water drained from the high-temperature steam pipe, the temperature is very high. This frequent start and stop process causes a lot of heat loss. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a system and method for heat recovery, storage and utilization of a solar thermal power generation project, thereby improving the economy and benefits of the solar thermal power generation project.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A system for heat recovery, storage and utilization of a solar thermal power generation project, comprising a steam turbine main steam system, a reheat steam system, a high- and low-pressure bypass system, a high-exhaust ventilation system, a drain system, a heat exchanger and a heat accumulator; the heat exchanger is respectively connected to the high-exhaust ventilation system, the high- and low-pressure bypass system and the drain system; the heat exchanger is also connected to a condenser or an exhaust device; the heat accumulator is connected to the heat exchanger via a heating pipe and a return water pipe; the heat accumulator is connected to a heating device.

[0006] A further improvement of the technical solution of the present invention is that: the high- and low-pressure bypass system is composed of two stages of high-pressure bypass and low-pressure bypass in series; the high-pressure bypass includes a high-pressure bypass pipeline connecting the main steam pipeline and the low-temperature reheat steam pipeline and a high-pressure bypass valve connected to the cooling water arranged on the high-pressure bypass pipeline; the low-pressure bypass includes a low-pressure bypass pipeline connecting the high-temperature reheat steam pipeline and the condenser or exhaust device and a low-pressure bypass valve connected to the cooling water arranged on the low-pressure bypass pipeline; a three-stage desuperheater is arranged at the tail end of the low-pressure bypass pipeline connected to the condenser or the exhaust device.

[0007] A further improvement of the technical solution of the present invention is that a first pipeline is led out through a first three-way connection in front of the low-pressure bypass valve and connected to the heat exchanger, and a first electric shut-off valve and a first check valve are arranged on the first pipeline.

[0008] A further improvement of the technical solution of the present invention is that: the high-exhaust ventilation system includes a high-exhaust ventilation duct connecting the low-temperature reheat steam duct and the condenser or the exhaust device; the sixth electric shut-off valve, the first high-pressure cylinder ventilation valve, the seventh electric shut-off valve and the desuperheater connected to the desuperheating water are arranged in sequence on the high-exhaust ventilation duct; a high-exhaust check valve is arranged on the low-temperature reheat steam duct, a bypass duct is arranged in parallel at both ends of the sixth electric shut-off valve and the first high-pressure cylinder ventilation valve, and a second high-pressure cylinder ventilation valve is arranged on the bypass duct.

[0009] A further improvement of the technical solution of the present invention is that a second pipeline is led out through a second three-way connection after the first high-pressure cylinder ventilation valve and before the seventh electric shut-off valve and connected to the heat exchanger, and a second electric shut-off valve and a second check valve are arranged on the second pipeline.

[0010] A further improvement of the technical solution of the present invention is that the drain system includes a turbine body drain, a main steam system drain, an extraction system drain, a reheat system drain, a drain header and a drain expansion tank; the drain header is respectively connected to the turbine body drain pipe, the main steam system drain pipe, the extraction system drain pipe, and the reheat system drain pipe, and is connected to the drain expansion tank.

[0011] A further improvement of the technical solution of the present invention is that a third pipeline is led out from the drain header and connected to the heat exchanger, and a third electric shut-off valve and a third check valve are arranged on the third pipeline.

[0012] A further improvement of the technical solution of the present invention is that a fourth electric shut-off valve is provided on the heating pipe connecting the heat accumulator and the heat exchanger; and a fifth electric shut-off valve is provided on the return water pipe connecting the heat accumulator and the heat exchanger.

[0013] A method for heat recovery, storage and utilization of a solar thermal power generation project, comprising: During the start-up and load reduction shutdown of the CSP unit steam turbine, the main steam generated by the steam generator superheater is cooled by the high-pressure bypass valve before the high-pressure main steam valve is opened, and then enters the low-temperature reheat steam pipeline. From the low-temperature reheat steam pipeline, it enters the steam generator reheater for heating and then enters the high-temperature reheat steam pipeline. Part or all of the high-temperature reheat steam is cooled by the low-pressure bypass valve and then enters the condenser or exhaust device; part or all of the high-temperature reheat steam is introduced into the heat exchanger before entering the low-pressure bypass valve, and is discharged into the condenser or exhaust device after the heat is recovered by the heat exchanger; During the start-up process of the steam turbine of the CSP unit, during the speed increase stage of the steam turbine under load, when the high-pressure cylinder blast high-discharge temperature rises to the set value, the first high-pressure cylinder ventilation valve opens to release pressure and cool down, and a part or all of the high-temperature steam is cooled by the first high-pressure cylinder ventilation valve and the desuperheater and then discharged into the condenser or exhaust device. A part or all of the high-temperature steam is directly discharged into the heat exchanger after the first high-pressure cylinder ventilation valve and before the desuperheater to recover heat and then discharged into the condenser or exhaust device; During the startup and load reduction shutdown of the CSP unit steam turbine, the steam turbine body drain valve, main steam system drain valve, extraction system drain valve, and reheat system drain valve are opened, and the high-temperature water after the drain enters the drain header and is mixed with the temperature is introduced into the heat exchanger to recover the heat and then discharged into the condenser or exhaust device; During the startup and load reduction shutdown process of the solar thermal unit turbine, the heat from the high and low pressure bypass system, high exhaust ventilation system and drain system is introduced into the heat exchanger for recovery, and the recovered heat is stored in the heat accumulator through the circulation of hot and cold water. The heat stored in the heat accumulator is directly used as a heating heat source.

[0014] A further improvement of the technical solution of the present invention is that the heating heat source can be used for heating the plant buildings of a solar thermal power plant, and can also be provided to heat users outside the plant.

[0015] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is: The present invention recovers and stores heat discharged into the condenser or exhaust device through the high and low pressure bypass system, the drain system and the high exhaust ventilation system during the frequent start and stop of the solar thermal unit by adding a heat exchanger and a heat accumulator to the high and low pressure bypass system, the drain system and the high exhaust ventilation system of the solar thermal power generation project. The heat stored in the heat accumulator can be directly used as a heating source for the solar thermal power plant building, and can also be provided to other heat users, effectively reducing the heat loss during the frequent start and stop of the solar thermal unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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 or the description of the prior art are briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. Figure 1 This is a schematic diagram of a system for heat recovery, storage and utilization of a solar thermal power generation project provided in an embodiment of the present invention; Among them, 1. heat exchanger; 2. heat accumulator; 3. condenser or exhaust device; 4. generator; 5. medium and low pressure cylinders; 6. high pressure cylinder; 7. steam generator superheater; 8. steam generator reheater; 9. high pressure bypass valve; 10. low pressure bypass valve; 11. sixth electric shut-off valve; 12. first high pressure cylinder ventilation valve; 13. desuperheater; 14. second high pressure cylinder ventilation valve; 15. high exhaust check valve; 16. drain header; 17. drain expansion tank; 18. third stage desuperheater; 19. high pressure main steam valve; 20. reheat main steam valve; 21. seventh electric shut-off valve. DETAILED DESCRIPTION

[0017] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatus.

[0018] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0019] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "several" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0020] The present invention is further described in detail below with reference to the accompanying drawings and embodiments: In conventional CSP systems, such as Figure 1 As shown, the high-temperature and high-pressure steam generated by the steam generator superheater 7 of the solar thermal system enters the high-pressure cylinder 6 of the steam turbine through the main steam pipeline and the high-pressure main steam valve 19 to expand and work, driving the generator 4 to generate electricity. The steam discharged from the high-pressure cylinder 6 after working enters the steam generator reheater 8 of the solar thermal system through the low-temperature reheat steam pipeline. The high-temperature steam heated by the steam generator reheater 8 enters the high-temperature reheat steam pipeline, enters the medium and low pressure cylinder 5 through the reheat main steam valve 20 to expand and work, driving the generator 4 to generate electricity. The exhaust steam is discharged into the condenser or exhaust device 3 through the low-pressure cylinder in the medium and low pressure cylinder 5, condensed, and then enters the condensate water supply system. It is sent to the solar thermal system heat exchanger through the condensate water supply system to be heated into steam to complete the cycle to generate electricity.

[0021] In order to realize heat recovery, storage and utilization of CSP projects and improve the economic efficiency and benefits of CSP projects, the present invention adds heat exchangers and heat accumulators to the high and low pressure bypass systems, high exhaust ventilation systems and drainage systems of CSP projects, thereby realizing the recovery and storage of heat discharged through the high and low pressure bypass systems, high exhaust ventilation systems and drainage systems during the frequent start and stop of CSP units. This heat can be directly used for heating the plant of CSP plants and can also be provided to other heat users. The specific scheme is as follows: like Figure 1 As shown, a system for heat recovery, storage and utilization of a solar thermal power generation project includes a turbine main steam system, a reheat steam system, a high-pressure and low-pressure bypass system, a high-exhaust ventilation system, a drain system, a heat exchanger 1 and a heat accumulator 2; the heat exchanger 1 is connected to the high-exhaust ventilation system, the high-pressure and low-pressure bypass system and the drain system respectively; the heat exchanger 1 is also connected to the condenser or the exhaust device 3; the heat accumulator 2 is connected to the heat exchanger 1 through a heating pipe and a return water pipe; the heat accumulator 2 is connected to the heating device.

[0022] Furthermore, the high- and low-pressure bypass system is composed of two stages of high-pressure bypass and low-pressure bypass in series; the high-pressure bypass includes a high-pressure bypass pipeline connecting the main steam pipeline and the low-temperature reheat steam pipeline and a high-pressure bypass valve 9 connected to the cooling water arranged on the high-pressure bypass pipeline; the low-pressure bypass includes a low-pressure bypass pipeline connecting the high-temperature reheat steam pipeline and the condenser or exhaust device 3 and a low-pressure bypass valve 10 connected to the cooling water arranged on the low-pressure bypass pipeline; a three-stage desuperheater 18 is arranged at the tail end where the low-pressure bypass pipeline is connected to the condenser or exhaust device 3.

[0023] Specifically, the high-low pressure bypass system of the steam turbine is composed of two-stage series bypass of high and low pressure. During the startup process of the unit, the main steam pressure and temperature are controlled according to the startup curve of the main engine. The main steam pressure is controlled by the high-pressure bypass. Before the turbine is started, the main steam valve is closed, and the high-temperature and high-pressure steam generated from the steam generator superheater 7 of the solar thermal system is sprayed with water by the high-pressure bypass valve 9 to reduce the temperature and enter the steam generator reheater 8 of the solar thermal system through the low-temperature reheat steam pipeline. After heating, it enters the high-temperature reheat system, and after spraying water by the low-pressure bypass valve 10 to reduce the temperature, it enters the condenser or exhaust device 3 to condense and enter the condensate water supply system. When the main steam pressure and temperature meet the requirements of the startup curve, the high-pressure main steam valve and the reheat main steam valve are opened, and the high-pressure bypass valve 9 and the low-pressure bypass valve 10 are closed. The turbine is started and the load is increased to normal operation. When the unit load changes or trips, the high-low pressure bypass system has a good regulating effect, so that the steam generation system and the turbine load are matched and run stably. In the present invention, the high-temperature reheated steam is introduced into the heat exchanger 1 before entering the low-pressure bypass valve 10, and is discharged into the condenser or the exhaust device 3 after the heat is recovered by the heat exchanger 1.

[0024] Furthermore, a first pipeline is led out through a first three-way connection before the low-pressure bypass valve 10 and connected to the heat exchanger 1 , and a first electric shut-off valve and a first check valve are provided on the first pipeline.

[0025] Furthermore, the high-exhaust ventilation system includes a high-exhaust ventilation duct connecting the low-temperature reheat steam duct and the condenser or exhaust device 3; the sixth electric shut-off valve 11, the first high-pressure cylinder ventilation valve 12, the seventh electric shut-off valve 21 and the desuperheater 13 connected to the desuperheating water are sequentially arranged on the high-exhaust ventilation duct; a high-exhaust check valve 15 is arranged on the low-temperature reheat steam duct, a bypass duct is arranged in parallel at both ends of the sixth electric shut-off valve 11 and the first high-pressure cylinder ventilation valve 12, and a second high-pressure cylinder ventilation valve 14 is arranged on the bypass duct.

[0026] Specifically, a high-discharge check valve 15 and a high-discharge ventilation duct are provided on the low-temperature reheat steam pipeline. During the turbine run-up process, the first high-pressure cylinder ventilation valve 12 is in an open state to maintain the temperature of the high-pressure cylinder 6 from overheating. The high-temperature steam of the high-discharge ventilation system enters the desuperheater 13 through the first high-pressure cylinder ventilation valve 12 and the second high-pressure cylinder ventilation valve 14 for cooling and then is discharged into the condenser or exhaust device 3. After the exhaust pressure of the high-pressure cylinder 6 increases, the high-discharge check valve 15 automatically opens, and the first high-pressure cylinder ventilation valve 12 and the second high-pressure cylinder ventilation valve 14 are closed. The present invention directly discharges the high-temperature steam into the heat exchanger 1 after the first high-pressure cylinder ventilation valve 12 and before the desuperheater 13 to recover heat and then discharges it into the condenser or exhaust device 3.

[0027] Furthermore, a second pipeline is led out through a second three-way connection after the first high-pressure cylinder ventilation valve 12 and before the seventh electric shut-off valve 21 and is connected to the heat exchanger 1 , and a second electric shut-off valve and a second check valve are arranged on the second pipeline.

[0028] Furthermore, the drain system includes a turbine body drain, a main steam system drain, an extraction system drain, a reheat system drain (including the drain of reheat steam and bypass system), a drain header 16 and a drain expansion tank 17; the drain header 16 is respectively connected to the turbine body drain pipe, the main steam system drain pipe, the extraction system drain pipe, and the reheat system drain pipe, and is connected to the drain expansion tank 17.

[0029] Specifically, during the startup and load reduction shutdown of the solar thermal unit steam turbine, the steam turbine body drain valve, the main steam system drain valve, the reheat system drain valve, and the steam extraction system drain valve are opened, and the drain generally enters the drain header 16 and is cooled by the drain empty container 17 before entering the condenser or exhaust device 3. In the present invention, the high-temperature water after entering the drain header 16 and mixing with the temperature is introduced into the heat exchanger 1 to recover the heat and then discharged into the condenser or exhaust device 3.

[0030] Furthermore, a third pipeline is led out from the drain header 16 and connected to the heat exchanger 1 , and a third electric shut-off valve and a third check valve are provided on the third pipeline.

[0031] Furthermore, a fourth electric shut-off valve is provided on the heating pipe connecting the heat accumulator 2 and the heat exchanger 1 ; and a fifth electric shut-off valve is provided on the return water pipe connecting the heat accumulator 2 and the heat exchanger 1 .

[0032] A method for heat recovery, storage and utilization of a solar thermal power generation project, comprising the following contents: During the start-up and load reduction shutdown process of the steam turbine of the solar thermal unit, the main steam generated by the steam generator superheater 7 is cooled by the high-pressure bypass valve 9 before the high-pressure main steam valve 19 is opened, and then enters the low-temperature reheat steam pipeline, enters the steam generator reheater 8 from the low-temperature reheat steam pipeline, and then enters the high-temperature reheat steam pipeline after being heated. A part (or all) of the high-temperature reheat steam is cooled by the low-pressure bypass valve 10 and then enters the condenser or exhaust device 3; a part (or all) of the high-temperature reheat steam is introduced into the heat exchanger 1 before entering the low-pressure bypass valve 10, and is discharged into the condenser or exhaust device 3 after the heat is recovered by the heat exchanger 1; During the start-up process of the steam turbine of the CSP unit, during the speed increase stage of the steam turbine with load, when the blast high-discharge temperature of the high-pressure cylinder 6 rises to the set value, the first high-pressure cylinder ventilation valve 12 opens to release pressure and cool down, and a part (or all) of the high-temperature steam is cooled by the first high-pressure cylinder ventilation valve 12 and the desuperheater 13 and then discharged into the condenser or exhaust device 3, and a part (or all) of the high-temperature steam is directly discharged into the heat exchanger 1 after the first high-pressure cylinder ventilation valve 12 and before the desuperheater 13 to recover heat and then discharged into the condenser or exhaust device 3; During the startup and load reduction shutdown of the CSP unit steam turbine, the steam turbine body drain valve, main steam system drain valve, extraction system drain valve, and reheat system drain valve are opened, and the high-temperature water after the drain enters the drain header 16 and the mixed temperature is introduced into the heat exchanger 1 to recover the heat and then discharged into the condenser or exhaust device 3; During the startup and load reduction shutdown process of the steam turbine of the solar thermal unit, the heat from the high and low pressure bypass system, the high exhaust ventilation system, and the drain system is introduced into the heat exchanger 1 for recovery, and the recovered heat is stored in the heat accumulator 2 through the circulation of cold and hot water. The heat stored in the heat accumulator 2 is directly used as a heating heat source.

[0033] Furthermore, the heating heat source can be used for heating the plant buildings of the solar thermal power plant, and can also be provided to heat users outside the plant.

[0034] In summary, the present invention recovers and stores the heat discharged into the condenser or exhaust device during the startup and load reduction shutdown process of the steam turbine of the solar thermal unit through a heat exchanger and an accumulator. The heat stored in the heat accumulator can be directly used as a heating source for the solar thermal power plant building, and can also be provided to other heat users, effectively reducing the heat loss during the frequent start and shutdown of the solar thermal unit.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for heat recovery, storage and utilization of a solar thermal power generation project, characterized by: The invention comprises a steam turbine main steam system, a reheat steam system, a high-pressure and low-pressure bypass system, a high-pressure exhaust ventilation system, a drain system, a heat exchanger (1) and a heat accumulator (2); the heat exchanger (1) is respectively connected to the high-pressure exhaust ventilation system, the high-pressure and low-pressure bypass system and the drain system; the heat exchanger (1) is also connected to a condenser or an exhaust device (3); the heat accumulator (2) is connected to the heat exchanger (1) via a heating pipe and a return water pipe; the heat accumulator (2) is connected to a heating device.

2. According to claim 1, a system for heat recovery, storage and utilization of a solar thermal power generation project is characterized by: The high- and low-pressure bypass system is composed of two stages of high-pressure bypass and low-pressure bypass connected in series; the high-pressure bypass includes a high-pressure bypass pipeline connecting the main steam pipeline and the low-temperature reheat steam pipeline and a high-pressure bypass valve (9) connected to the desuperheating water and arranged on the high-pressure bypass pipeline; the low-pressure bypass includes a low-pressure bypass pipeline connecting the high-temperature reheat steam pipeline and the condenser or exhaust device (3) and a low-pressure bypass valve (10) connected to the desuperheating water and arranged on the low-pressure bypass pipeline; a three-stage desuperheater (18) is arranged at the tail end of the low-pressure bypass pipeline connected to the condenser or exhaust device (3).

3. According to claim 2, a system for heat recovery, storage and utilization of a solar thermal power generation project is characterized by: A first pipeline is led out through a first three-way connection in front of the low-pressure bypass valve (10) and connected to the heat exchanger (1). A first electric shut-off valve and a first check valve are arranged on the first pipeline.

4. According to claim 1, a system for heat recovery, storage and utilization of a solar thermal power generation project is characterized by: The high-pressure exhaust ventilation system comprises a high-pressure exhaust ventilation duct connecting a low-temperature reheat steam duct and a condenser or an exhaust device (3); a sixth electric shut-off valve (11), a first high-pressure cylinder ventilation valve (12), a seventh electric shut-off valve (21) and a desuperheater (13) connected to desuperheating water are sequentially arranged on the high-pressure exhaust ventilation duct; a high-pressure exhaust check valve (15) is arranged on the low-temperature reheat steam duct, a bypass duct is arranged in parallel at both ends of the sixth electric shut-off valve (11) and the first high-pressure cylinder ventilation valve (12), and a second high-pressure cylinder ventilation valve (14) is arranged on the bypass duct.

5. The system for heat recovery, storage and utilization of a solar thermal power generation project according to claim 4, characterized in that: A second pipeline is led out from behind the first high-pressure cylinder ventilation valve (12) and before the seventh electric shut-off valve (21) through a second three-way connection and connected to the heat exchanger (1). A second electric shut-off valve and a second check valve are arranged on the second pipeline.

6. The system for heat recovery, storage and utilization of a solar thermal power generation project according to claim 1, characterized in that: The drain system comprises a turbine body drain, a main steam system drain, an extraction system drain, a reheat system drain, a drain header (16) and a drain expansion tank (17); the drain header (16) is respectively connected to the turbine body drain pipe, the main steam system drain pipe, the extraction system drain pipe and the reheat system drain pipe, and is also connected to the drain expansion tank (17).

7. A system for heat recovery, storage and utilization of a solar thermal power generation project according to claim 6, characterized in that: A third pipeline is led out from the drain header (16) and connected to the heat exchanger (1), and a third electric shut-off valve and a third check valve are arranged on the third pipeline.

8. The system for heat recovery, storage and utilization of a solar thermal power generation project according to claim 1, characterized in that: A fourth electric shut-off valve is provided on the heating pipeline connecting the heat accumulator (2) and the heat exchanger (1); and a fifth electric shut-off valve is provided on the return water pipeline connecting the heat accumulator (2) and the heat exchanger (1).

9. A method for heat recovery, storage and utilization in a solar thermal power generation project, using the system according to any one of claims 1 to 8, characterized in that: The method comprises: During the start-up and load reduction shutdown of the steam turbine of the solar thermal unit, the main steam generated by the steam generator superheater (7) is cooled by the high-pressure bypass valve (9) before the high-pressure main steam valve (19) is opened, and then enters the low-temperature reheat steam pipeline. From the low-temperature reheat steam pipeline, the main steam enters the steam generator reheater (8) and enters the high-temperature reheat steam pipeline after being heated. A part or all of the high-temperature reheat steam is cooled by the low-pressure bypass valve (10) and then enters the condenser or exhaust device (3). A part or all of the high-temperature reheat steam is introduced into the heat exchanger (1) before entering the low-pressure bypass valve (10), and then discharged into the condenser or exhaust device (3) after heat is recovered by the heat exchanger (1). During the start-up process of the steam turbine of the solar thermal power unit, at the speed increase stage of the steam turbine under load, when the blast high-discharge temperature of the high-pressure cylinder (6) rises to a set value, the first high-pressure cylinder ventilation valve (12) opens to release pressure and cool down the temperature, and a part or all of the high-temperature steam is cooled by the first high-pressure cylinder ventilation valve (12) and the desuperheater (13) before being discharged into the condenser or exhaust device (3); a part or all of the high-temperature steam is directly discharged into the heat exchanger (1) after the first high-pressure cylinder ventilation valve (12) and before the desuperheater (13) to recover heat before being discharged into the condenser or exhaust device (3); During the startup and load reduction shutdown process of the steam turbine of the solar thermal unit, the steam turbine body drain valve, the main steam system drain valve, the extraction system drain valve, and the reheat system drain valve are opened, and the drains from each line enter the drain header (16) and the high-temperature water after mixing is introduced into the heat exchanger (1) to recover the heat and then discharged into the condenser or the exhaust device (3); During the startup and load reduction shutdown process of the steam turbine of the solar thermal unit, heat from the high and low pressure bypass system, the high exhaust ventilation system, and the drain system is introduced into the heat exchanger (1) for recovery, and the recovered heat is stored in the heat accumulator (2) through the circulation of cold and hot water. The heat stored in the heat accumulator (2) is directly used as a heating heat source.

10. A method for heat recovery, storage and utilization of a solar thermal power generation project according to claim 9, characterized in that: The heating heat source can be used for heating the plant buildings of a solar thermal power plant, and can also be provided to heat users outside the plant.

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