Coupling double-tank indirect solar photo-thermal energy storage boiler complementary multistage steam supply system

Abstract

The invention provides a coupling double-tank indirect solar photo-thermal energy storage boiler complementary multistage steam supply system. The system comprises a solar storage system, a double-tank heat release system, a multistage heater, a thermal power heat supply system and a steam supply system. The solar storage system comprises a solar tower, and a fused salt storage heat exchanger and a fused salt main heat exchanger which are connected with a fused salt outlet of the solar tower; a fused salt outlet of the fused salt main heat exchanger is connected with a fused salt inlet of the multi-stage heater; the double-tank heat release system comprises a hot tank and a cold tank, the thermal power heat supply system comprises a boiler, a heat regeneration system and a steam turbine, water supply ports of the boiler and the heat regeneration system are connected with a water inlet of the multi-stage heater, and a steam outlet of the multi-stage heater and a steam outlet of the boiler are connected with a steam inlet of the steam turbine; the multi-stage heater and the steam outlet of the boiler are connected with a steam supply system, under the condition that the deep peak regulation requirement of a power grid is met, the industrial steam supply requirement can be guaranteed, and the power generation coal consumption of a unit can be reduced.

Description

Technical Field

[0001] This disclosure belongs to the field of energy utilization technology, specifically relating to a boiler complementary multi-stage steam supply system with coupled dual-tank indirect solar thermal energy storage. Background Technology

[0002] Under the current dual-carbon requirements of achieving carbon peaking and carbon neutrality, the proportion of renewable energy sources such as wind and solar power is becoming increasingly significant. However, the intermittent and fluctuating nature of these renewable energy sources presents new challenges to the power grid. Against this backdrop, combined heat and power (CHP) units, while providing industrial steam, also frequently participate in peak shaving. This forces existing thermal power units to meet the parameter requirements of dual-stage industrial steam supply by employing main steam desuperheating and pressure reduction methods under low-load conditions, resulting in poor thermal economy and increased coal consumption.

[0003] There are four commonly used high-pressure industrial steam supply technologies for existing cogeneration units: cold resteam extraction heating, hot resteam extraction heating, main steam desuperheating and pressure reduction heating, and main steam back-pressure turbine heating. Among these, for the most commonly used 300MW-class thermal power units in China, cold resteam extraction heating and hot resteam extraction heating are difficult to provide the industrial parameters of 3MPa and a steam supply of 100t / h under 50% THA conditions. Main steam desuperheating and pressure reduction heating can meet the high-pressure steam supply requirements under low-load conditions, but it requires the use of a main steam back-pressure turbine for heating, and also requires the construction of a back-pressure turbine plant, the purchase of back-pressure turbines and related valves, resulting in high upfront investment costs, especially when steam supply demand fluctuates, leading to unstable economic returns. Summary of the Invention

[0004] This disclosure aims to at least solve one of the technical problems existing in the prior art, and to provide a boiler complementary multi-stage steam supply system with coupled dual-tank indirect solar thermal energy storage.

[0005] One aspect of this disclosure proposes a boiler-complementary multi-stage steam supply system with coupled dual-tank indirect solar thermal energy storage. The system includes: a solar energy storage system, a dual-tank heat release system, a multi-stage heater, a thermal power heating system, and a steam supply system; wherein... The solar energy storage system includes a solar tower, and a molten salt storage heat exchanger and a molten salt main heat exchanger, which are respectively connected to the molten salt outlet of the solar tower; the molten salt outlet of the molten salt main heat exchanger is connected to the molten salt inlet of the multi-stage heater; The dual-tank heat release system includes a hot tank and a cold tank connected to the molten salt storage heat exchanger. The hot tank is used to store high-temperature molten salt and to provide high-temperature molten salt when solar energy is insufficient. The cold tank is used to store low-temperature molten salt. The thermal power heating system includes a boiler, a regenerative system, and a steam turbine. The feedwater inlets of the boiler and the regenerative system are connected to the inlets of the multi-stage heaters. The steam outlets of the multi-stage heaters and the boiler are connected to the steam inlets of the steam turbines. The multi-stage heater is connected to the steam outlet of the boiler via the steam supply system.

[0006] Optionally, the multi-stage heater includes a main heater, and the turbine includes a high-pressure cylinder, wherein... The molten salt outlet of the molten salt main heat exchanger is connected to the molten salt inlet of the main heater; The inlet of the main heater is connected to the regeneration system and the feedwater of the boiler. The main steam outlet of the main heater and the main steam outlet of the boiler are connected to the main steam inlet of the high-pressure cylinder through the main steam pipeline. The feedwater absorbs heat in the main heater to form high-temperature steam, which enters the high-pressure cylinder together with the main steam generated by the main heater.

[0007] Optionally, the steam supply system includes a main steam supply subsystem connected to the main steam pipeline for providing industrial steam at a pressure of 3-24 MPa.

[0008] Optionally, the cold resteam outlet of the high-pressure cylinder is connected to the cold resteam inlet of the boiler via a cold resteam pipeline; wherein, The steam supply system includes a cold reheat industrial steam supply subsystem, which is connected to the cold reheat steam pipeline and is used to provide industrial steam at a pressure of 1.5 MPa.

[0009] Optionally, the multi-stage heater further includes a first-stage heater, and the steam turbine includes an intermediate-pressure cylinder; wherein, The molten salt inlet of the first-stage heater is connected to the molten salt outlet of the molten salt main heat exchanger. The hot resteam outlet of the first-stage heater is connected to the hot resteam outlet of the boiler and the hot resteam inlet of the intermediate-pressure cylinder through a hot resteam pipeline. The first-stage heater is also connected to the feedwater inlet of the regenerative system and the feedwater inlet of the boiler. The feedwater absorbs heat in the first-stage heater to form high-temperature steam, which enters the intermediate-pressure cylinder together with the hot resteam generated by the first-stage heater.

[0010] Optionally, the steam supply system includes a hot resteam supply subsystem connected to the hot resteam pipeline for providing industrial steam at a pressure of 1.5 MPa.

[0011] Optionally, the multi-stage heater further includes a second-stage heater, the molten salt inlet of which is connected to the molten salt outlet of the main heater and the molten salt outlet of the first-stage heater, respectively, and the molten salt outlet of the second-stage heater is connected to the molten salt inlet of the molten salt main heat exchanger.

[0012] Optionally, the second-stage heater is also connected to a steam supply pipeline, the steam supply system including a molten salt industry steam supply subsystem connected to the steam supply pipeline, and... The second-stage heater is also connected to the water inlet of the regenerative system. The water absorbs heat in the second-stage heater to form high-temperature steam, which is used to provide 1.5MPa-level industrial steam to the molten salt industrial steam supply subsystem.

[0013] Another aspect of this disclosure proposes a steam supply method for a boiler-complementary multi-stage steam supply system with coupled dual-tank indirect solar thermal energy storage as described above, the steam supply method comprising: Solar towers are used to collect solar heat. When there is sufficient sunlight, part of the high-temperature molten salt coming out of the solar tower enters the molten salt storage heat exchanger, and the other part enters the molten salt main heat exchanger to provide heat to the multi-stage heaters. When solar radiation is insufficient, the high-temperature molten salt in the hot tank enters the molten salt storage heat exchanger to release heat, and then enters the cold tank. The molten salt medium in the molten salt main heat exchanger absorbs heat in the molten salt storage heat exchanger and releases heat in the molten salt main heat exchanger to provide heat to the multi-stage heater. The high-temperature molten salt from the molten salt main heat exchanger, along with the low-temperature water from the boiler and the regenerative system, enters the multi-stage heater. The low-temperature water in the multi-stage heater absorbs the heat from the high-temperature molten salt to form steam, which, together with the steam generated by the boiler, flows into the steam turbine. At the same time, some of the steam also forms industrial steam, which is used to supply industrial steam to the steam supply system.

[0014] This disclosure proposes a boiler complementary multi-stage steam supply system with coupled dual-tank indirect solar thermal energy storage, which has the following beneficial effects: This disclosure fully utilizes solar thermal energy while also incorporating multi-stage heating of condensate into superheated steam for industrial steam supply, achieving multi-stage energy utilization of the thermal system. Furthermore, by utilizing the molten salt system portion of the unit's main steam, the cold reheat steam heating flow rate can be significantly increased, reducing heating energy consumption. In summary, this disclosed solution achieves multi-stage solar energy utilization while ensuring industrial steam supply needs under deep peak-shaving conditions. Implementation of this solution can contribute to energy conservation and emission reduction, helping to achieve dual-carbon goals. Attached Figure Description

[0015] Figure 1This is a schematic diagram of a boiler complementary multi-stage steam supply system with coupled dual-tank indirect solar thermal energy storage according to Embodiment 1 of this disclosure. Detailed Implementation

[0016] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.

[0017] Example 1 like Figure 1 As shown in the example, this example provides a boiler complementary multi-stage steam supply system with coupled dual-tank indirect solar thermal energy storage, including: a solar energy storage system, a dual-tank heat release system, a multi-stage heater, a thermal power heating system, and a steam supply system.

[0018] Please continue to refer to the following: Figure 1 The solar energy storage system includes a solar tower 111, and a molten salt storage heat exchanger 112 and a molten salt main heat exchanger 113, which are respectively connected to the molten salt outlet of the solar tower 111. Meanwhile, the molten salt outlet of the molten salt main heat exchanger 113 is connected to the molten salt inlet of the multi-stage heater.

[0019] For further information, please continue to refer to [link / reference]. Figure 1 The dual-tank heat release system includes a hot tank 121 and a cold tank 122 connected to the molten salt storage heat exchanger 112. The hot tank 121 is used to store high-temperature molten salt and to provide high-temperature molten salt in the event of insufficient solar energy. The cold tank 122 is used to store low-temperature molten salt.

[0020] Furthermore, the multi-stage heater includes a main heater 131, a first-stage heater 132, and a second-stage heater 133. The molten salt outlet of the molten salt main heat exchanger 113 is connected to the molten salt inlets of the main heater 131 and the first-stage heater 132, respectively. The molten salt inlet of the molten salt main heat exchanger 113 is connected to the molten salt outlet of the second-stage heater 133. At the same time, the molten salt inlet of the second-stage heater 133 is also connected to the molten salt outlets of the main heater 131 and the first-stage heater 132, forming a molten salt circuit.

[0021] Based on the above structure, under sufficient sunlight, part of the high-temperature molten salt coming out of the solar tower enters the molten salt storage heat exchanger to heat the molten salt in the cold tank, and part enters the molten salt main heat exchanger to supply the heat exchange required by the main heater, the first-stage heater, and the second-stage heater.

[0022] Additionally, solar heat can be stored in a hot tank using a molten salt storage heat exchanger. During the storage process, molten salt flows out from a cold tank, absorbs heat in the molten salt storage heat exchanger, and then enters the hot tank. Thus, in situations with insufficient solar energy, the high-temperature molten salt in the hot tank releases heat by entering the molten salt storage heat exchanger and then enters the cold tank. The molten salt medium in the molten salt storage heat exchanger absorbs heat in the main heat exchanger and then releases heat in the main heat exchanger, supplying the heat required for the main heater, the first-stage heater, and the second-stage heater.

[0023] Furthermore, please continue to refer to... Figure 1 The thermal power heating system includes a boiler 141, a regenerative system, a steam turbine, and a generator 144, among other structures.

[0024] For details, please continue to refer to Figure 1 The regenerative system includes a deaerator 142-1, a feedwater pump 142-2, a first high-pressure heater 142-3, a second high-pressure heater 142-4, a third high-pressure heater 142-5, a first low-pressure heater 142-6, a second low-pressure heater 142-7, a third low-pressure heater 142-8, a fourth low-pressure heater 142-9, a condensate pump 142-10, and a condenser 142-11.

[0025] For details, please continue to refer to Figure 1 The steam turbine includes a high-pressure cylinder 143-1, an intermediate-pressure cylinder 143-2, and a low-pressure cylinder 143-3.

[0026] Based on the above structure, such as Figure 1 As shown, the connection between the thermal power heating system and the solar energy storage system is as follows: the main steam outlet of the main heater 131 and the main steam outlet of the boiler 141 are connected to the main steam inlet of the high-pressure cylinder 143-1 through the main steam pipeline a. Simultaneously, the feedwater inlet of the boiler 141 is connected to the inlet of the main heater 131 through the first feedwater pipeline b. That is, the boiler inlet feedwater absorbs heat in the main heat exchanger to form high-temperature, high-pressure steam, which then flows into the unit's main steam system; at the same time, the condensate from the feedwater pump outlet is pressurized, absorbs heat in the main heater, and forms high-temperature steam, which then flows into the unit's reheat steam system. This steam production process forms a complementary steam system of solar thermal power and coal-fired boiler.

[0027] Please continue to refer to this. Figure 1 As shown, the high-pressure cylinder 143-1 not only has a main steam inlet but also a cold reheat steam outlet. The cold reheat steam outlet of the high-pressure cylinder 143-1 is connected to the cold reheat steam inlet of the boiler 141 through the cold reheat steam pipeline c. The low-temperature reheat steam (cold reheat steam) discharged from the high-pressure cylinder 143-1 returns to the boiler reheater through the cold reheat steam pipeline. After being reheated into high-temperature hot reheat steam, it is sent to the intermediate-pressure cylinder to continue to do work, thereby improving the steam utilization efficiency.

[0028] Please continue to refer to this. Figure 1 As shown, the high-pressure cylinder in this embodiment is also connected to the first high-pressure heater 142-3 and the second high-pressure heater 142-4 through the steam extraction pipeline. The first high-pressure heater 142-3 and the second high-pressure heater 142-4 are connected in series on the second feedwater pipeline d between the outlet of the feedwater pump 142-2 and the inlet of the boiler 141. Of course, the second feedwater pipeline d is also connected to the main heater 131. In this way, the water discharged from the high-pressure cylinder is heated by the first high-pressure heater and the second high-pressure heater and then transferred to the boiler feedwater, reducing the boiler's fuel consumption.

[0029] Please continue to refer to this. Figure 1 As shown, the hot resteam outlet of the first-stage heater 132 and the hot resteam outlet of the boiler 141 are connected to the hot resteam inlet of the intermediate-pressure cylinder 143-2 through the hot resteam pipeline e.

[0030] Please continue to refer to this. Figure 1 As shown, the intermediate pressure cylinder 143-2 is also connected to the third high pressure heater 142-5 and the deaerator 142-1 through the steam extraction pipeline. A feed water pump 142-2 is installed between the deaerator 142-1 and the third high pressure heater 142-5. Of course, the third high pressure heater 142-5, the feed water pump 142-2 and the deaerator 142-1 are also connected to the second feed water pipeline d to heat the feed water and increase the temperature of the feed water flowing into the boiler.

[0031] It should be noted that, in addition to being connected to the second feedwater pipeline, the deaerator is also connected to the inlet of the second-stage heater 133 and the inlet of the first-stage heater 132 via the third feedwater pipeline f. In other words, the feedwater treated by the deaerator will be pressurized by the feedwater pump and then delivered to different systems via two main paths to achieve the dual functions of "boiler steam supplement" and "industrial steam supply". One path supplies the boiler and the main heater. The pressurized high-pressure feedwater is sent to the boiler through the second feedwater pipeline and is finally heated into high-temperature and high-pressure main steam. At the same time, the high-pressure feedwater is also sent to the main heater, where it absorbs the heat of the high-temperature molten salt to form high-temperature and high-pressure steam, which merges with the main steam generated by the boiler and flows into the high-pressure cylinder. Another route supplies the second-stage heater. The pressurized high-pressure feedwater is sent to the second-stage heater through the third feedwater pipeline. After absorbing the heat of the high-temperature molten salt, it is heated to the parameters of 3MPa and 280℃ for industrial steam supply. This route of high-pressure feedwater is also sent to the first-stage heater, where it absorbs the heat of the high-temperature molten salt to form hot reheat steam, which merges with the hot reheat steam of the boiler and flows into the intermediate-pressure cylinder.

[0032] Furthermore, please continue to refer to... Figure 1The intermediate pressure cylinder 143-2 is connected to the low pressure cylinder 143-3 through a connecting pipe, and the energy is transmitted to the low pressure cylinder. The low pressure cylinder undergoes "multi-stage expansion" to drive the low pressure cylinder rotor to rotate and drive the generator to generate electricity.

[0033] Furthermore, such as Figure 1 As shown, the low-pressure cylinder 143-3 is connected to the generator 144 and is coaxial with the rotors of the high-pressure cylinder and the intermediate-pressure cylinder, jointly driving the generator rotor to rotate and converting the mechanical energy generated by the steam in the low-pressure cylinder into electrical energy. Additionally, the low-pressure cylinder 143-3 is connected to the condenser 142-11 via an exhaust pipe. The exhaust steam discharged from the low-pressure cylinder 143-3 condenses into condensate in the condenser 142-11. The condensate outlet at the bottom of the condenser 142-11 is connected to the condensate pump 142-10. The condensate pump 142-10 is connected to the deaerator 142-1 via a fourth feedwater pipeline. The fourth feedwater pipeline is equipped with a first low-pressure heater 142-6, a second low-pressure heater 142-7, a third low-pressure heater 142-8, and a fourth low-pressure heater 142-9. The condensate is pressurized by the condensate pump 142-10 and delivered to each low-pressure heater for heating.

[0034] It should be further noted that the molten salt temperature at the outlet of the main molten salt heat exchanger is generally 590℃, while the main steam and hot reheat steam temperatures under THA conditions are both 566℃. The design based on the main heater enables the replacement of the boiler to provide part of the main steam. Additionally, the low-temperature molten salt temperature output from the second-stage heater to the cryogenic tank is 300℃.

[0035] In addition to the aforementioned molten salt and boiler complementary system, the main innovation of this embodiment lies in the inclusion of a steam supply system. Please refer to [link to previous document]. Figure 1 The steam supply system includes a main steam supply subsystem 151, which is connected to the main steam pipeline a and is used to provide industrial steam at a pressure of 3-24 MPa. In other words, high-pressure industrial steam is supplied by drawing main steam from the molten salt system and the coal-fired boiler outlet; this point can provide industrial steam at pressures of 3 MPa and above.

[0036] Additionally, please continue to refer to Figure 1 The steam supply system in this embodiment includes a cold reheat industrial steam supply subsystem 152, which is connected to the cold reheat steam pipeline c and is used to provide industrial steam at a pressure of 1.5 MPa. In other words, a portion of the steam is drawn from the unit's cold reheat steam pipeline to provide industrial steam at a pressure of 1.5 MPa.

[0037] Additionally, please continue to refer to Figure 1The steam supply system of this embodiment also includes a hot resteam supply subsystem 153, which is connected to the hot resteam pipeline e and is used to provide industrial steam at a pressure of 1.5 MPa.

[0038] Additionally, please continue to refer to Figure 1 The steam supply system in this embodiment also includes a molten salt industrial steam supply subsystem 154. Simultaneously, the second-stage heater 133 is connected to a molten salt industrial steam supply pipeline g. The molten salt industrial steam supply subsystem 154 is connected to the molten salt industrial steam supply pipeline g and is used to provide 3MPa, 300°C steam to the industry. In other words, condensate from the deaerator is pressurized by a water pump and then absorbs heat in the first-stage heater to form 3MPa-level industrial steam for external heating.

[0039] It should be understood that the main steam supply subsystem 151, the cold reheat industrial steam supply subsystem 152, the hot reheat steam supply subsystem 153, and the molten salt industrial steam supply subsystem 154 together constitute the steam supply system. This means that the system in this embodiment simultaneously has a molten salt industrial steam supply system, a cold reheat industrial steam supply system, a main steam supply system, and a hot reheat steam supply system, which are used to provide industrial steam supply for different needs.

[0040] This implementation method utilizes a solar energy storage system in conjunction with a thermal power heating system to form a complementary steam system of solar thermal and coal-fired boilers. This system provides heat to the steam turbine and different grades of industrial steam, creating a molten salt industrial steam supply system, a cold reheat industrial steam supply system, a main steam supply system, and a hot reheat steam supply system. This achieves multi-stage utilization of solar energy while ensuring industrial steam supply needs are met under deep peak-shaving conditions, thus contributing to energy conservation and emission reduction and supporting the achievement of dual-carbon goals. In other words, this implementation method adds a steam supply system to the existing solar thermal and boiler complementary system, meeting different levels of industrial steam supply needs and fulfilling multiple requirements for both heating and steam supply.

[0041] Example 2 This example illustrates a steam supply method for a boiler-complementary multi-stage steam supply system coupled with dual-tank indirect solar thermal energy storage. The specific process is as follows: (1) Solar heat is collected by solar tower. Under sufficient sunlight, part of the high-temperature molten salt from the solar tower enters the molten salt storage heat exchanger to heat the molten salt in the cold tank, and part enters the main heat exchanger to supply the heat exchange required by the main heater, the first stage heater and the second stage heater. (2) In the case of insufficient solar energy, the high-temperature molten salt in the hot tank is released into the molten salt storage heat exchanger and then enters the cold tank. The molten salt medium in the molten salt storage heat exchanger absorbs heat in the molten salt storage heat exchanger and then releases heat in the molten salt main heat exchanger to supply the heat exchange required by the main heater, the first stage heater and the second stage heater; (3) After the boiler inlet feedwater absorbs heat in the main heater to form high-temperature and high-pressure steam, it flows into the unit's main steam system; at the same time, the condensate at the feedwater pump outlet is pressurized and absorbs heat in the main heater to form high-temperature steam, which flows into the unit's reheat steam system. The above steam production process forms a complementary steam system of solar thermal and coal-fired boiler.

[0042] (4) Molten salt industrial steam supply system: The condensate from the deaerator is pressurized by a water pump and then absorbs heat in the second-stage heat exchanger to form 3MPa-level industrial steam for external heating.

[0043] (5) Cold Recycled Industrial Steam Supply System: A portion of the steam is drawn from the cold recycled steam header of the unit for industrial steam supply at a pressure of 1.5 MPa.

[0044] (6) Main steam supply system: High-pressure industrial steam supply is provided by drawing main steam from the molten salt system and coal-fired boiler outlet. This site can provide industrial steam at a pressure of 3~24MPa.

[0045] (7) Hot resteam supply system: Industrial steam supply is provided by extracting hot resteam from the molten salt system and coal-fired boiler outlet. This site can provide industrial steam at a level of 1.5 MPa.

[0046] This embodiment can form a complementary multi-stage steam supply system based on solar thermal energy storage and boiler, which can provide steam under various conditions, including when solar energy is abundant or insufficient. Based on this system, different grades of industrial steam can be provided to industrial systems, effectively reducing costs. While meeting the deep peak shaving requirements of the power grid, it can both ensure the industrial steam supply needs and reduce the coal consumption of the generating unit.

[0047] Compared with a conventional 350MW supercritical unit (main steam pressure 24.2MPa, main steam temperature 566℃, reheat steam temperature 566℃, back pressure set at 4.9kPa), when the industrial steam supply parameters are pressure 3MPa, temperature 280℃, extraction steam rate 100t / h, and main steam flow rate set at 1008.51t / h, the coal consumption for power generation of the proposed scheme is only 235.03 g / kWh, while the coal consumption for power generation of the conventional cogeneration scheme is only 276.57 g / kWh. The coal consumption for power generation of the proposed scheme is reduced by 41.54 g / kWh, demonstrating a significant coal-saving effect.

[0048] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A boiler complementary multi-stage steam supply system with coupled dual-tank indirect solar thermal energy storage, characterized in that, The system includes: a solar energy storage system, a dual-tank heat release system, a multi-stage heater, a thermal power heating system, and a steam supply system; wherein... The solar energy storage system includes a solar tower, and a molten salt storage heat exchanger and a molten salt main heat exchanger, which are respectively connected to the molten salt outlet of the solar tower; the molten salt outlet of the molten salt main heat exchanger is connected to the molten salt inlet of the multi-stage heater; The dual-tank heat release system includes a hot tank and a cold tank connected to the molten salt storage heat exchanger. The hot tank is used to store high-temperature molten salt and to provide high-temperature molten salt when solar energy is insufficient. The cold tank is used to store low-temperature molten salt. The thermal power heating system includes a boiler, a regenerative system, and a steam turbine. The feedwater inlets of the boiler and the regenerative system are connected to the inlets of the multi-stage heaters. The steam outlets of the multi-stage heaters and the boiler are connected to the steam inlets of the steam turbines. The multi-stage heater is connected to the steam outlet of the boiler via the steam supply system.

2. The system according to claim 1, characterized in that, The multi-stage heater includes a main heater, and the steam turbine includes a high-pressure cylinder, wherein... The molten salt outlet of the molten salt main heat exchanger is connected to the molten salt inlet of the main heater; The inlet of the main heater is connected to the regeneration system and the feedwater of the boiler. The main steam outlet of the main heater and the main steam outlet of the boiler are connected to the main steam inlet of the high-pressure cylinder through the main steam pipeline. The feedwater absorbs heat in the main heater to form high-temperature steam, which enters the high-pressure cylinder together with the main steam generated by the main heater.

3. The system according to claim 2, characterized in that, The steam supply system includes a main steam supply subsystem, which is connected to the main steam pipeline and is used to provide industrial steam at a pressure of 3-24 MPa.

4. The system according to claim 2, characterized in that, The cold resteam outlet of the high-pressure cylinder is connected to the cold resteam inlet of the boiler via a cold resteam pipeline; wherein, The steam supply system includes a cold reheat industrial steam supply subsystem, which is connected to the cold reheat steam pipeline and is used to provide industrial steam at a pressure of 1.5 MPa.

5. The system according to claim 2, characterized in that, The multi-stage heater further includes a first-stage heater, and the steam turbine includes an intermediate-pressure cylinder; wherein... The molten salt inlet of the first-stage heater is connected to the molten salt outlet of the molten salt main heat exchanger. The hot resteam outlet of the first-stage heater is connected to the hot resteam outlet of the boiler and the hot resteam inlet of the intermediate-pressure cylinder through a hot resteam pipeline. The first-stage heater is also connected to the feedwater inlet of the regenerative system and the feedwater inlet of the boiler. The feedwater absorbs heat in the first-stage heater to form high-temperature steam, which enters the intermediate-pressure cylinder together with the hot resteam generated by the first-stage heater.

6. The system according to claim 5, characterized in that, The steam supply system includes a hot resteam supply subsystem connected to the hot resteam pipeline, which provides industrial steam at a pressure of 1.5 MPa.

7. The system according to claim 5, characterized in that, The multi-stage heater also includes a second-stage heater, the molten salt inlet of which is connected to the molten salt outlet of the main heater and the molten salt outlet of the first-stage heater, respectively, and the molten salt outlet of the second-stage heater is connected to the molten salt inlet of the molten salt main heat exchanger.

8. The system according to claim 7, characterized in that, The second-stage heater is also connected to a steam supply pipeline, the steam supply system including a molten salt industry steam supply subsystem connected to the steam supply pipeline, and... The second-stage heater is also connected to the water inlet of the regenerative system. The water absorbs heat in the second-stage heater to form high-temperature steam, which is used to provide 1.5MPa-level industrial steam to the molten salt industrial steam supply subsystem.

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