Heat extraction and supply system for deep peak regulation of thermal power units and operation method thereof

Abstract

This application discloses a heat extraction and supply system and operating method for deep peak shaving of a thermal power unit. The system includes a boiler, a steam turbine module, a high-pressure heater, a deaerator, a low-pressure heater, a condenser, a molten salt heat exchange system, and a steam-water heat exchanger. The boiler is connected to the high-pressure cylinder of the steam turbine via a main steam pipe and to the intermediate-pressure cylinder of the steam turbine via a reheat steam pipe. The steam turbine module is connected to the high-pressure heater and the low-pressure heater via an extraction pipe. The reheat steam extraction pipe transports reheated steam to the steam-molten salt heat exchanger for heat exchange. The non-condensable gas outlet of the steam-molten salt heat exchanger is connected to the steam-water heat exchanger via a non-condensable gas pipe for waste heat recovery. The condenser is connected to the low-pressure heater and the steam-water heat exchanger via pipes to achieve condensate circulation. This system can achieve graded utilization of steam thermal energy and cascaded recovery of waste heat, improving the heating performance of the thermal power unit and is suitable for thermal power operation scenarios with fluctuating loads.

Description

Technical Field

[0001] The present application relates to the field of thermal power generation technology, and in particular to a heat extraction and supply system for deep peak regulation of a thermal power unit and an operation method thereof. Background Art

[0002] Thermal power plants are a vital component of the modern energy system, and their thermal energy efficiency directly impacts the economic and environmental performance of electricity and heating. By utilizing high-temperature steam in turbines in stages and combining it with extraction heating technology, thermal power plants can achieve cogeneration, providing stable power output to the grid while also meeting regional heating needs. In recent years, to further improve energy efficiency, an increasing number of thermal power plants have incorporated molten salt heat exchange technology. This technology leverages the high heat capacity of molten salt to store and release thermal energy, meeting variable heating needs.

[0003] In existing thermal power plant heating systems, molten salt heat exchange technology is primarily used to store excess heat during low-load periods and release it during peak heating demand. However, in traditional designs, the connection between the molten salt heat exchanger and the heating network is relatively simple, typically requiring heat energy to be transferred through a boiler or other intermediate links before it can be transferred to the heating network. This heat transfer method not only has a slow response time, which can easily lead to insufficient heat supply during peak heating demand, but can also increase heat transfer losses, reducing the overall operating efficiency of the system.

[0004] In existing thermal power plant heat extraction and supply systems, the heat released by the molten salt heat exchanger during peak heating periods must pass through boilers or other complex pathways before entering the heating network, limiting the direct and efficient use of this heat. Due to the inefficient dynamic connection between the molten salt heat exchanger and the heating network, the system cannot quickly respond to changes in the heating load, affecting heating performance. Therefore, optimizing the connection between the molten salt heat exchanger and the heating network to enable direct and efficient heat transfer to the heating network during peak heating periods is a key issue that needs to be addressed in the existing technology. Summary of the Invention

[0005] The present application provides a heat extraction and supply system and operation method for deep peak regulation of thermal power units, which is used to solve the problem in the prior art that the dynamic connection efficiency between the molten salt heat exchange device and the heating network is low and it is difficult to quickly respond to the heating peak.

[0006] The technical solutions adopted in this application are as follows:

[0007] On the one hand, the present application provides a heat extraction and supply system for deep peak regulation of a thermal power unit, comprising a boiler, a steam turbine module, a high-pressure heater, a deaerator, a low-pressure heater, a condenser, a molten salt heat exchange system, and a steam-water heat exchanger;

[0008] The steam turbine module includes a steam turbine high-pressure cylinder, a steam turbine intermediate-pressure cylinder and a steam turbine low-pressure cylinder. The boiler is used to generate high-temperature and high-pressure steam. The boiler is connected to the steam turbine high-pressure cylinder through a main steam pipe. The boiler is also connected to the steam turbine intermediate-pressure cylinder through a reheat steam pipe. A reheat steam extraction pipe is provided on the reheat steam pipe. The output end of the reheat steam extraction pipe is connected to the steam inlet of the steam-molten salt heat exchanger to transfer the thermal energy of the steam to the molten salt. The steam-molten salt heat exchanger is provided with a non-condensable gas outlet and is connected to a first non-condensable gas pipe. The non-condensable gas outlet of the steam-molten salt heat exchanger is connected to the steam-water heat exchanger through the first non-condensable gas pipe to transport the uncondensed steam to the steam-water heat exchanger for reuse; the steam turbine high-pressure cylinder is connected to the reheat inlet of the boiler through a first exhaust pipe, and the steam turbine intermediate-pressure cylinder is connected to the steam inlet of the steam turbine low-pressure cylinder through a second exhaust pipe. The low-pressure cylinder of the steam turbine is connected to the condenser through a third exhaust pipe, and the outlet of the condenser is connected to the low-pressure heater via a condensate pump. The high-pressure cylinder of the steam turbine is connected to a first extraction pipe, the intermediate-pressure cylinder of the steam turbine is connected to a second extraction pipe, and the low-pressure cylinder of the steam turbine is connected to a third extraction pipe. The high-pressure cylinder of the steam turbine and the intermediate-pressure cylinder of the steam turbine are respectively connected to the extraction inlet of the high-pressure heater through the first extraction pipe and the second extraction pipe. The low-pressure cylinder of the steam turbine is connected to the extraction inlet of the low-pressure heater through the third extraction pipe. The first outlet feedwater pipe of the high-pressure heater is connected to the superheater inlet of the boiler. The intermediate-pressure cylinder of the steam turbine is also connected to a fourth exhaust pipe. The intermediate-pressure cylinder of the steam turbine is connected to the extraction inlet of the deaerator through the fourth exhaust pipe. The high-pressure heater is connected to the extraction inlet of the deaerator through a first drain pipe, and the low-pressure heater is connected to the extraction inlet of the deaerator through a second outlet feedwater pipe.

[0009] In an optional embodiment, the molten salt heat exchange system includes a steam-molten salt heat exchanger, a molten salt hot tank, a molten salt cold tank and a molten salt-feed water heat exchanger, the molten salt output end of the molten salt-feed water heat exchanger is connected to the input end of the molten salt cold tank through a pipeline, the output end of the molten salt cold tank is connected to the molten salt input end of the steam-molten salt heat exchanger through a pipeline, the molten salt output end of the steam-molten salt heat exchanger is connected to the input end of the molten salt hot tank through a pipeline, and the output end of the molten salt hot tank is connected to the molten salt input end of the molten salt-feed water heat exchanger through a pipeline; the outlet water feed pipe of the deaerator is respectively connected to the high-pressure heater and the molten salt-feed water heat exchanger through a feed water pump, the heating water outlet of the molten salt-feed water heat exchanger is connected to a heating water supply pipe, and the heating water outlet of the molten salt-feed water heat exchanger is connected to the first outlet feed water pipe through the heating water supply pipe to transport the heated feed water in the molten salt-feed water heat exchanger to the boiler.

[0010] In an optional embodiment, a pressure reducing valve is provided on the reheat steam extraction pipeline.

[0011] In an optional embodiment, the low-pressure heater is connected to the condenser through a second drain pipe, the steam-water heat exchanger is provided with a non-condensable gas outlet and is connected to a second non-condensable gas pipe, and the non-condensable gas outlet of the steam-water heat exchanger is connected to the condenser through the second non-condensable gas pipe.

[0012] In an optional embodiment, the steam-water heat exchanger is connected to the deaerator through a drain return pipe.

[0013] In an optional embodiment, a pressure water pump is provided on the drain return pipe, and the steam-water heat exchanger is also connected to a normal-pressure water pump. The inlet of the normal-pressure water pump is connected to a normal-pressure water source, and the outlet of the normal-pressure water pump is connected to the water input end of the steam-water heat exchanger through a pipe, so as to transport normal-pressure water to the steam-water heat exchanger.

[0014] In an optional embodiment, the steam-water heat exchanger is connected to the heating network via a heating pipe.

[0015] In an optional embodiment, the steam-molten salt heat exchanger adopts a spiral coil heat exchange structure to improve heat transfer efficiency.

[0016] In an optional embodiment, a heating bypass pipe is connected to the heating water supply pipe, the heating bypass pipe is connected to the heating supply pipe, and a regulating valve is provided on the heating bypass pipe.

[0017] On the other hand, the present application further provides an operating method for a heat extraction and heating system for deep peak shaving of a thermal power unit, which is applied to the heat extraction and heating system for deep peak shaving of a thermal power unit provided in the present application. The operating method includes:

[0018] a. Steam cycle process:

[0019] a1. High-temperature and high-pressure steam generated by the boiler is transported to the high-pressure cylinder of the steam turbine through the main steam pipeline;

[0020] a2. The steam discharged from the high-pressure cylinder of the steam turbine enters the reheater of the boiler through the first exhaust pipe for reheating to form reheated steam;

[0021] a3. The reheated steam is transported to the intermediate pressure cylinder of the steam turbine through the reheated steam pipe, and the steam discharged from the intermediate pressure cylinder of the steam turbine is transported to the low pressure cylinder of the steam turbine through the second exhaust steam pipe;

[0022] a4. The steam discharged from the low-pressure cylinder of the steam turbine is transported to the condenser through the third exhaust pipe for cooling and recovery;

[0023] b. Molten salt heat exchange cycle process:

[0024] b1. The reheated steam is introduced into the steam-molten salt heat exchanger through the reheated steam extraction pipeline to transfer heat energy to the molten salt;

[0025] b2. The uncondensed steam in the steam-molten salt heat exchanger is transported through the non-condensable gas outlet and the first non-condensable gas pipeline to the steam-water heat exchanger for further utilization of waste heat;

[0026] b3. The heated molten salt is transported to the molten salt-feed water heat exchanger through the molten salt hot tank to transfer heat to the feed water;

[0027] b4. The cooled molten salt returns to the steam-molten salt heat exchanger through the molten salt cold tank, completing the molten salt closed-loop circulation;

[0028] c. Water supply circulation process:

[0029] c1. The deaerator deoxygenates the feed water, and the treated feed water is transported to the high-pressure heater and the molten salt-feed water heat exchanger through the feed water pump;

[0030] c2. The feed water heated in the molten salt-feed water heat exchanger is transported to the superheater inlet of the boiler through the heating water supply pipe for further heating;

[0031] c3. During the peak heating period, part of the heated feed water is directly transported to the heating pipeline through the heating bypass pipeline to meet the heating demand;

[0032] c4. The drain generated in the steam-water heat exchanger is transported to the deaerator through the drain return pipe to complete the closed-loop circulation.

[0033] Compared with the prior art, this application has the following beneficial effects:

[0034] 1. The heat extraction and heating system for deep peak regulation of thermal power units provided in this application is a heat extraction and heating system that directly transports the reheated steam of the boiler to the steam inlet of the steam-molten salt heat exchanger through the reheated steam pipe through the reheated steam extraction pipe, which can realize the direct transfer of steam heat to the molten salt. This design eliminates the complex path in which the steam heat needs to pass through multiple stages of equipment in the traditional system and can reduce the loss of heat during the transfer process. At the same time, the reheated steam pipe connects the boiler and the steam turbine intermediate pressure cylinder to transport reheated steam to the steam turbine intermediate pressure cylinder. The reheated steam extraction pipe is connected to the reheated steam pipe, which can directly introduce part of the reheated steam into the steam-molten salt heat exchanger, thereby realizing efficient transfer of reheated steam thermal energy. Through this connection method, the steam-molten salt heat exchanger can receive high-temperature reheated steam from the boiler, providing a stable source of heat energy for molten salt heat exchange.

[0035] 2. The steam-molten salt heat exchanger of this application is provided with a non-condensable gas outlet and connected to the steam-water heat exchanger via a first non-condensable gas pipeline. Uncondensed steam can enter the steam-water heat exchanger for secondary heat transfer, further recovering the waste heat into the heating network. This design approach can solve the problem of non-condensable steam being directly discharged in the prior art and extend the heat transfer path through a reasonable layout. Moreover, through the multiple utilization of non-condensable steam, the present application can significantly improve the overall heat recovery capacity of the system, while reducing heat loss and providing a more stable heat source support for the heating network.

[0036] 3. This application establishes an orderly connection between the boiler, the turbine module and the steam-molten salt heat exchanger through the main steam pipe, the reheat steam pipe and the reheat steam extraction pipe. After the steam is released in stages from the high-pressure cylinder of the turbine and the intermediate-pressure cylinder of the turbine, a portion of the reheated steam enters the molten salt heat exchange system through the reheat steam extraction pipe, where the steam-molten salt heat exchanger completes the transfer of heat to the molten salt. This design enables the molten salt heat exchange system to dynamically connect to the entire heating process, reducing the intermediate steps required for heat transfer from steam to the heating system, shortening the heat transfer time, and this application can achieve efficient coordination with the heating network through the reasonable layout of the molten salt heat exchange system, thereby improving the problem of slow heating response caused by inflexible heat distribution in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0038] Figure 1 A schematic diagram of a heat extraction and supply system for deep peak regulation of a thermal power unit provided in one embodiment of the present application;

[0039] Figure 2 A schematic diagram of a heat extraction and supply system for deep peak regulation of a thermal power unit provided in another embodiment of the present application;

[0040] Figure 3 A schematic diagram of a heat extraction and supply system for deep peak regulation of a thermal power unit provided in yet another embodiment of the present application. DETAILED DESCRIPTION

[0041] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts also fall within the scope of protection of this application.

[0042] In the description of this application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0043] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this application, unless otherwise specified, "plurality" means two or more.

[0044] In the description of this application, it should be noted that, unless otherwise specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0045] See also Figure 1-Figure 3 An embodiment of the present application provides a heat extraction and supply system for deep peak regulation of a thermal power unit, including a boiler 100, a turbine module 200, a high-pressure heater 300, a deaerator 400, a low-pressure heater 500, a condenser 600, a molten salt heat exchange system 700 and a steam-water heat exchanger 800.

[0046] Among them, the turbine module 200 includes a turbine high-pressure cylinder 210, a turbine intermediate-pressure cylinder 220 and a turbine low-pressure cylinder 230. The boiler 100 is used to generate high-temperature and high-pressure steam. The boiler 100 is connected to the turbine high-pressure cylinder 210 through the main steam pipe 101. The boiler 100 is also connected to the turbine intermediate-pressure cylinder 220 through the reheat steam pipe 102. A reheat steam extraction pipe 103 is provided on the reheat steam pipe 102. The output end of the reheat steam extraction pipe 103 is connected to the steam inlet of the steam-molten salt heat exchanger 710 to transfer the thermal energy of the steam to the molten salt.

[0047] At the same time, in order to solve the problem in the prior art that the waste heat after steam heat exchange is often not fully utilized, resulting in waste of heat energy, in this embodiment, the steam-molten salt heat exchanger 710 is provided with a non-condensable gas outlet and is connected to a first non-condensable gas pipeline 711. The non-condensable gas outlet of the steam-molten salt heat exchanger 710 is connected to the steam-water heat exchanger 800 through the first non-condensable gas pipeline 711 to transport the uncondensed steam to the steam-water heat exchanger 800 for reuse, and then transfer it to the heating network or boiler water supply system. Such a design significantly improves the steam utilization efficiency, realizes the deep coupling between the steam, molten salt and water cycles, and thus reduces the overall energy loss of the system.

[0048] Furthermore, the high-pressure cylinder 210 of the steam turbine is connected to the reheater inlet of the boiler 100 through the first exhaust pipe 211, the intermediate-pressure cylinder 220 of the steam turbine is connected to the steam inlet of the low-pressure cylinder 230 of the steam turbine through the second exhaust pipe 221, and the low-pressure cylinder 230 of the steam turbine is connected to the condenser 600 through the third exhaust pipe 231. The outlet of the condenser 600 is connected to the low-pressure heater 500 via the condensate pump 610. The high-pressure cylinder 210 of the turbine is connected to a first steam extraction pipe 212, the intermediate-pressure cylinder 220 of the turbine is connected to a second steam extraction pipe 222, and the low-pressure cylinder 230 of the turbine is connected to a third steam extraction pipe 232. The high-pressure cylinder 210 of the turbine and the intermediate-pressure cylinder 220 of the turbine are connected to the steam extraction inlet of the high-pressure heater 300 through the first steam extraction pipe 212 and the second steam extraction pipe 222 respectively, and the low-pressure cylinder 230 of the turbine is connected to the steam extraction inlet of the low-pressure heater 500 through the third steam extraction pipe 232. This multi-stage steam extraction design facilitates dynamic adjustment of the steam extraction amount according to the power generation load and heating demand, so that the heating and power generation are coordinated and optimized, thereby ensuring the overall efficiency of the system operation. The first outlet water supply pipe 320 of the high-pressure heater 300 is connected to the superheater inlet of the boiler 100. The turbine intermediate-pressure cylinder 220 is also connected to a fourth exhaust pipe 223. The turbine intermediate-pressure cylinder 220 is connected to the steam extraction inlet of the deaerator 400 through the fourth exhaust pipe 223. The high-pressure heater 300 is connected to the steam extraction inlet of the deaerator 400 through the first drain pipe 310. The low-pressure heater 500 is connected to the steam extraction inlet of the deaerator 400 through the second outlet water supply pipe 520.

[0049] The heat extraction and heating system for deep peak regulation of thermal power units provided in the embodiment of the present application is a heat extraction and heating system that directly transports the reheated steam of the boiler 100 through the reheated steam extraction pipe 103 to the steam inlet of the steam-molten salt heat exchanger 710 through the reheated steam pipe 102, which can realize the direct transfer of steam heat to the molten salt. This design eliminates the complex path in which the steam heat needs to be transferred through multiple stages of equipment in the traditional system, and can reduce the loss of heat during the transfer process. At the same time, the reheated steam pipe 102 connects the boiler 100 and the steam turbine intermediate pressure cylinder 220, and is used to transport reheated steam to the steam turbine intermediate pressure cylinder 220. The reheated steam extraction pipe 103 is connected to the reheated steam pipe 102, and part of the reheated steam can be directly introduced into the steam-molten salt heat exchanger 710, thereby realizing efficient transfer of reheated steam heat energy. Through this connection method, the steam-molten salt heat exchanger 710 can receive high-temperature reheated steam from the boiler, providing a stable source of heat energy for molten salt heat exchange.

[0050] In the above-mentioned embodiment of the present application, the steam-molten salt heat exchanger 710 is connected to the steam-water heat exchanger 800 by setting a non-condensable gas outlet and through a first non-condensable gas pipeline 711. The steam that is not fully condensed can enter the steam-water heat exchanger 800 for secondary heat transfer, and the waste heat is further recovered to the heating network. This design method can solve the problem of non-condensable steam being directly discharged in the prior art, and the heat transfer path is extended by a reasonable layout. Moreover, this design not only utilizes the sensible heat of steam, but also recovers latent heat to the maximum extent, thereby realizing the coordinated operation of steam and molten salt. Through the multiple utilization of non-condensable steam in the present application, the ability of the system's overall heat recovery can be significantly improved, while reducing heat loss, providing a more stable heat source support for the heating network.

[0051] In addition, the embodiment of the present application establishes an orderly connection between the boiler 100, the turbine module 200 and the steam-molten salt heat exchanger 710 through the main steam pipe 101, the reheat steam pipe 102 and the reheat steam extraction pipe 103. After the steam is released in stages in the turbine high-pressure cylinder 210 and the turbine intermediate-pressure cylinder 220, a portion of the reheated steam enters the molten salt heat exchange system 700 through the reheat steam extraction pipe 103, wherein the steam-molten salt heat exchanger 710 completes the transfer of heat to the molten salt. This design enables the molten salt heat exchange system 700 to dynamically access the entire heating process, reducing the intermediate steps required for heat transfer from steam to the heating system, shortening the heat transfer time, and the present application can achieve efficient coordination with the heating network through the reasonable layout of the molten salt heat exchange system 700, thereby improving the problem of slow heating response caused by inflexible heat distribution in the prior art.

[0052] In some embodiments, the molten salt heat exchange system 700 includes a steam-molten salt heat exchanger 710, a molten salt hot tank 720, a molten salt cold tank 730, and a molten salt-feed water heat exchanger 740. The molten salt output end of the molten salt-feed water heat exchanger 740 is connected to the input end of the molten salt cold tank 730 through a pipeline, the output end of the molten salt cold tank 730 is connected to the molten salt input end of the steam-molten salt heat exchanger 710 through a pipeline, the molten salt output end of the steam-molten salt heat exchanger 710 is connected to the input end of the molten salt hot tank 720 through a pipeline, and the output end of the molten salt hot tank 720 is connected to the molten salt input end of the steam-molten salt heat exchanger 710 through a pipeline. The outlet end is connected to the molten salt input end of the molten salt-feed water heat exchanger 740 through a pipeline, forming a closed-loop circulation path for the molten salt. During use, the reheated steam can enter the steam-molten salt heat exchanger 710 through the reheated steam extraction pipe 103. After transferring the heat energy to the molten salt, the molten salt is transported to the molten salt hot tank 720 to store heat, and then releases the heat to the feed water through the molten salt-feed water heat exchanger 740 according to system requirements. Such a closed-loop design can ensure the high efficiency of molten salt heat storage and transfer, laying the foundation for the flexible response of the heating system.

[0053] In the prior art, the connection relationship between the molten salt heat exchange device and the boiler and the steam-water heat exchanger is relatively fixed, and it cannot flexibly respond to the needs of multi-stage thermal energy utilization. This embodiment designs a molten salt heat exchange circuit consisting of a steam-molten salt heat exchanger 710, a molten salt hot tank 720, a molten salt cold tank 730 and a molten salt-feedwater heat exchanger 740, which can achieve dynamic coupling between the molten salt heat exchange system 700 and the boiler water supply and heating network during operation. In addition, the steam-molten salt heat exchanger 710 is connected to the reheat steam extraction pipe 103, so that the molten salt can fully absorb the heat in the steam, store thermal energy in the molten salt hot tank 720, and then flexibly release heat according to the heating demand, which can not only reduce the direct consumption of steam, but also efficiently utilize multi-stage thermal energy.

[0054] Furthermore, the outlet water supply pipe 410 of the deaerator 400 is connected to the high-pressure heater 300 and the molten salt-feed water heat exchanger 740 respectively via the feed water pump 420. The heated water outlet of the molten salt-feed water heat exchanger 740 is connected to the heating water supply pipe 741. The heating water outlet of the molten salt-feed water heat exchanger 740 is connected to the first outlet water supply pipe 320 via the heating water supply pipe 741 to transport the heated feed water in the molten salt-feed water heat exchanger 740 to the boiler 100. This method can efficiently transfer the heat released by the molten salt to the boiler water supply. Unlike the traditional single-path heating method, this design can directly utilize the heat stored in the molten salt heat exchange system 700 during the water supply process of the boiler 100, reducing the intermediate transfer links and reducing heat loss. In addition, the heating water supply pipe 741 can ensure the stability of the water supply temperature and improve the operating efficiency of the boiler 100.

[0055] The core function of the molten salt-feedwater heat exchanger 740 is to directly heat the feedwater by releasing the heat energy of the molten salt to meet the heating demand. In this embodiment, the heating water supply pipe 741 is connected to the first outlet water supply pipe 320, thereby connecting the heating water supply pipe 741 to the boiler 100. In actual use, it can provide a flexible heat distribution method. Especially when the boiler load is high or the heating demand increases suddenly, the molten salt heat exchange system 700 can quickly transfer heat to the boiler 100 through the heating water supply pipe 741, indirectly supporting the heating network and significantly improving the system's heating response speed and efficiency.

[0056] In some embodiments, a pressure reducing valve 104 is provided on the reheat steam extraction pipe 103 .

[0057] In the above embodiment, by providing a pressure reducing valve 104 on the reheat steam extraction pipe 103, the pressure of the reheat steam transported from the boiler 100 to the steam-molten salt heat exchanger 710 through the reheat steam extraction pipe 103 can be adjusted. The steam pressure regulation function can reduce the steam pressure to an appropriate level according to the working requirements of the steam-molten salt heat exchanger 710, thereby optimizing the efficiency of the transfer of steam heat to the molten salt. Through such a design, the equipment damage to the steam-molten salt heat exchanger 710 caused by excessive steam pressure is avoided, and the load of the molten salt heat exchange system 700 during operation is also reduced, thereby making the operation of the lifting system more stable. In addition, the provision of the pressure reducing valve 104 makes the pressure of the reheat steam more controllable, further enhances the adjustment capability of the system, enables it to adapt to the heat transfer requirements under various working conditions, and provides a guarantee for the safety and flexibility of the system operation.

[0058] In some embodiments, the low-pressure heater 500 is connected to the condenser 600 through a second drain pipe 510, the steam-water heat exchanger 800 is provided with a non-condensable gas outlet and is connected to a second non-condensable gas pipe 810, and the non-condensable gas outlet of the steam-water heat exchanger 800 is connected to the condenser 600 through the second non-condensable gas pipe 810.

[0059] In the above embodiment, by connecting a second drain pipe 510 between the low-pressure heater 500 and the condenser 600, and connecting the non-condensable gas outlet of the steam-water heat exchanger 800 to the condenser 600 through the second non-condensable gas pipe 810, centralized discharge and treatment of drain and non-condensable gas can be achieved. The drain generated by the low-pressure heater 500 directly enters the condenser 600 through the second drain pipe 510, avoiding system pressure fluctuations caused by drain accumulation and improving drain recovery efficiency. The uncondensed gas in the steam-water heat exchanger 800 enters the condenser 600 through the second non-condensable gas pipe 810, and is further cooled and treated after being fully contacted with the cooling water of the condenser 600. This design reduces the heat waste and energy efficiency loss caused by the direct discharge of non-condensable gas into the environment. Through the above layout, the discharge paths of the low-pressure heater 500 and the steam-water heat exchanger 800 are optimized, which not only improves the stability of system operation, but also simplifies the condensate and drain recovery process, further improving the resource utilization efficiency of the thermal power unit heating system.

[0060] In some embodiments, steam-water heat exchanger 800 is connected to deaerator 400 via a drain return pipe 820. This drain return pipe 820 is used to transport drain from steam-water heat exchanger 800 to deaerator 400, forming a closed-loop water circulation system. This design not only reduces water waste during the heating process, but also ensures efficient operation of the system in terms of thermal energy utilization and water circulation.

[0061] In some embodiments, a pressure water pump 840 is provided on the drain return pipe 820, which can quickly transport the drain generated in the steam-water heat exchanger 800 back to the deaerator 400 to complete the reuse of the circulating water, avoid the retention of drain in the pipe or the problem of reduced flow rate due to gravity, thereby helping to improve the drain recovery efficiency. The steam-water heat exchanger 800 is also connected to a normal pressure water pump 830, the inlet of the normal pressure water pump 830 is connected to the normal pressure water source, and the outlet of the normal pressure water pump 830 is connected to the water input end of the steam-water heat exchanger 800 through a pipe, for transporting normal pressure water to the steam-water heat exchanger 800, thereby ensuring that the steam-water heat exchanger 800 can obtain sufficient water support under various working conditions. The design adopted in this embodiment makes drain return and water source replenishment more flexible and rapid through the cooperation of two pumps, which can improve the operating stability of the steam-water heat exchanger 800 and reduce the fluctuation of the heating system that may be caused by poor water flow.

[0062] In some embodiments, as Figure 2 As shown, the steam-water heat exchanger 800 is connected to the heating network via a heating pipe 801 .

[0063] This embodiment connects the steam-water heat exchanger 800 to the heating pipe 801 and further connects it to the heating network, thereby enabling direct transfer of waste steam heat to the heating network. This connection method can quickly transfer the heat recovered from the steam-water heat exchanger 800 to the heating network, effectively reducing the intermediate links in the heat transfer path, thereby reducing heat loss. In addition, by connecting the heating network through the heating pipe 801, the heat recovered by the steam-water heat exchanger 800 can be flexibly used to meet regional heating needs and improve heat utilization efficiency. This layout method enables the heating system to dynamically adjust the heat distribution in the heating pipe according to the actual heat load demand, providing a more stable and continuous heat source for the heating network, while reducing the pressure on other heating modules, thereby optimizing the overall operating performance of the system. Through such a design, this embodiment enables the steam-water heat exchanger 800 to not only play a role in recovering heat, but also provide key support in the dynamic heat balance of the heating network.

[0064] In some embodiments, the steam-molten salt heat exchanger 710 uses a spiral coil heat exchange structure to improve heat transfer efficiency.

[0065] The spiral coil heat exchange structure employed in steam-molten salt heat exchanger 710 increases the effective heat exchange area, enabling heat transfer between steam and molten salt over a shorter path. This results in more efficient heat exchange between the two, avoiding the localized dead zones that can occur in traditional straight-tube heat exchangers and improving heat transfer uniformity. Furthermore, the compact design of the spiral coil structure reduces the overall size of the heat exchanger, helping to reduce equipment installation space requirements and optimize the overall layout of the molten salt heat exchange system 700.

[0066] In some embodiments, as Figure 3 As shown, the heating water supply pipe 741 is connected to a heating bypass pipe 742 , the heating bypass pipe 742 is connected to the heat supply pipe 801 , and a regulating valve 743 is provided on the heating bypass pipe 742 .

[0067] In the prior art, the heat energy released by the molten salt heat exchanger is difficult to directly enter the heating network, and the response speed is slow, which limits the flexibility and efficiency of the system. In this embodiment, by connecting the heating bypass pipe 742 to the heating water supply pipe 741 and directly connecting it to the heating pipe 801, during the peak heating period, the heated feed water can be preferentially transported directly to the heating network through the regulating valve 743 without the need for secondary heating in the boiler. This method can significantly improve the system's heat energy distribution efficiency during peak heating periods, achieve the goal of quickly responding to heating needs, and avoid the response lag problem caused by the lengthy heat energy transfer path in traditional systems.

[0068] The present application also provides an operating method for a deep peak-shaving heat extraction and heating system for a thermal power plant, which is applied to the deep peak-shaving heat extraction and heating system for a thermal power plant provided in the above-mentioned embodiment of the present application. The operating method includes:

[0069] a. Steam cycle process:

[0070] a1. The high-temperature and high-pressure steam generated by the boiler 100 is transported to the high-pressure cylinder 210 of the steam turbine through the main steam pipe 101;

[0071] a2. The steam discharged from the high-pressure cylinder 210 of the steam turbine enters the reheater of the boiler 100 through the first exhaust pipe 211 for reheating to form reheated steam;

[0072] a3. The reheated steam is delivered to the intermediate pressure cylinder 220 of the steam turbine through the reheated steam pipe 102, and the steam discharged from the intermediate pressure cylinder 220 of the steam turbine is delivered to the low pressure cylinder 230 of the steam turbine through the second exhaust steam pipe 221;

[0073] a4. The steam discharged from the low-pressure cylinder 230 of the steam turbine is transported to the condenser 600 through the third exhaust pipe 231 for cooling and recovery;

[0074] b. Molten salt heat exchange cycle process:

[0075] b1. The reheated steam is introduced into the steam-molten salt heat exchanger 710 through the reheated steam extraction pipe 103 to transfer heat energy to the molten salt;

[0076] b2. The uncondensed steam in the steam-molten salt heat exchanger 710 is transported through the non-condensable gas outlet and the first non-condensable gas pipeline 711 to the steam-water heat exchanger 800 for further utilization of waste heat;

[0077] b3. The heated molten salt is transported to the molten salt-feedwater heat exchanger 740 through the molten salt hot tank 720 to transfer heat to the feedwater;

[0078] b4. The cooled molten salt returns to the steam-molten salt heat exchanger 710 through the molten salt cold tank 730, completing the molten salt closed-loop circulation;

[0079] c. Water supply circulation process:

[0080] c1. The deaerator 400 deoxygenates the feed water, and the treated feed water is transported to the high-pressure heater 300 and the molten salt-feed water heat exchanger 740 through the feed water pump 420;

[0081] c2. The feed water heated in the molten salt-feed water heat exchanger 740 is transported to the superheater inlet of the boiler 100 through the heating water supply pipe 741 for further heating;

[0082] c3. During the peak heating period, part of the heated feed water is directly delivered to the heating pipe 801 through the heating bypass pipe 742 to meet the heating demand;

[0083] c4. The drain generated in the steam-water heat exchanger 800 is transported to the deaerator 400 through the drain return pipe 820, completing a closed-loop cycle.

[0084] In the above embodiment, the steam cycle process adopted can realize the graded release and transfer of heat energy. When in use, high-temperature and high-pressure steam is transported from the boiler 100 to the turbine high-pressure cylinder 210 through the main steam pipe 101, and then passes through the turbine medium-pressure cylinder 220 and the turbine low-pressure cylinder 230 in sequence. This method enables the sensible heat of steam to be fully utilized at different pressures, which not only reduces the situation where the steam heat energy is quickly exhausted in one link, but also provides a suitable steam heat source for the subsequent steam-molten salt heat exchanger 710 and steam-water heat exchanger 800 of the system. At the same time, by transporting the steam discharged from the low-pressure cylinder to the condenser 600 for cooling and recovery, a closed-loop path of the steam cycle is formed. This design effectively reduces the waste of heat energy, makes the heat utilization of steam more uniform, and provides stable thermal energy support for the overall operation of the system.

[0085] The molten salt heat exchange cycle process transfers the thermal energy of the steam to the molten salt by introducing the reheated steam from the reheated steam extraction pipe 103 into the steam-molten salt heat exchanger 710, completing a sensible heat transfer. The steam that is not fully condensed enters the steam-water heat exchanger 800 through the non-condensable gas pipe 711 to achieve secondary waste heat utilization. In this process, molten salt acts as an intermediate heat storage medium, and completes the heat storage and release functions through the circulation of the molten salt hot tank 720 and the cold tank 730, thereby improving the system's regulation ability under heat load fluctuations. Especially when the heating demand changes, the molten salt heat exchange system 700 can respond quickly and transfer the stored heat to the feed water through the molten salt-feed water heat exchanger 740, realizing multi-stage heat utilization. This design reduces the direct loss of heat energy and provides a more stable heat source for the heating system.

[0086] During the water supply circulation process, the feed water treated by the deaerator 400 is transported to the high-pressure heater 300 and the molten salt-feed water heat exchanger 740 through the feed water pump 420 to complete the heating of the feed water. During the peak heating period, part of the feed water heated by the molten salt-feed water heat exchanger 740 directly enters the heating pipe 801 through the heating bypass pipe 742, achieving rapid heat supply and avoiding the time delay of boiler reheating. At the same time, the drain generated in the steam-water heat exchanger 800 returns to the deaerator 400 through the drain return pipe 820, forming a closed-loop recovery of water resources. This design not only improves the efficiency of water supply utilization, but also enables the heating network to dynamically adjust the heat distribution path, thereby maintaining the stability and flexibility of the heating network under different heating demands.

[0087] The heating system provided in the embodiment of the present application has a certain load regulation capability and can adapt to deep peak load regulation conditions, as described below:

[0088] This system can dynamically adjust the heat distribution between heating and power generation. This application realizes the step-by-step release of steam thermal energy through the multi-stage path design of steam between the boiler 100, the turbine module 200 and the molten salt heat exchange system 700. The high-temperature and high-pressure steam generated by the boiler enters the turbine high-pressure cylinder 210, the turbine medium-pressure cylinder 220 and the turbine low-pressure cylinder 230 in sequence, gradually releasing heat energy to drive the turbine to generate electricity. This hierarchical utilization design avoids the rapid depletion of steam thermal energy in a single link. At the same time, part of the steam is introduced into the steam-molten salt heat exchanger 710 through the reheat steam extraction pipe 103 to provide a heat source for the molten salt heat exchange system 700. Under low-load conditions, by reasonably adjusting the steam extraction volume, the steam demand for the medium and low-pressure cylinders of the turbine can be reduced, and flexible switching between heating and power generation loads can be achieved.

[0089] The heat storage and release capabilities of the molten salt heat exchange system of the embodiment of the present application can enhance the adaptability of the system. The molten salt heat exchange system 700 provides the system with a dynamic heat regulation function through the synergistic effect of the steam-molten salt heat exchanger 710, the molten salt hot tank 720 and the molten salt-feed water heat exchanger 740. When operating at low load, the system can store excess heat energy through the molten salt hot tank to provide reserve support for subsequent peak loads; and when the demand for heating suddenly increases, the molten salt-feed water heat exchanger 740 heats the feed water by quickly releasing the stored heat. Part of the heated feed water can directly enter the heating pipe 801 through the heating bypass pipe 742 to meet the needs of the heating network. This design reduces the intermediate links in heat transfer, shortens the response time, and improves the regulation capability of the heating load.

[0090] At the same time, the closed-loop design of the water circulation system can optimize resource utilization and load regulation. In terms of water circulation, the system realizes the closed-loop circulation of condensed water and drain during the heating process through the close connection of the deaerator 400, the steam-water heat exchanger 800 and the drain return pipe 820. The uncondensed waste heat steam in the steam-water heat exchanger 800 is further utilized, and the drain generated is returned to the deaerator 400 through the drain return pipe for subsequent water heating. At the same time, during the water supply circulation process, the system can dynamically adjust the water supply path according to different load conditions. For example, during the peak heating period, heated water is directly delivered to the heating pipe through the heating bypass pipe. This optimized design of the water cycle reduces the waste of heat energy and water resources, while ensuring the stability of the system during low-load operation, providing good support for deep peak-shaving conditions.

[0091] In summary, the heating system of the present embodiment, through the organic combination of steam circulation, molten salt heat exchange circulation, and water circulation, can dynamically adjust the heat distribution between heating and power generation to adapt to the load requirements under different operating conditions. The synergistic effect of cascade utilization, dynamic storage, and resource recovery gives the system a certain load regulation capability, which can meet the high flexibility and stability requirements of deep peak operation.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A heat extraction and supply system for deep peak regulation of thermal power units, characterized in that: It includes a boiler (100), a steam turbine module (200), a high-pressure heater (300), a deaerator (400), a low-pressure heater (500), a condenser (600), a molten salt heat exchange system (700) and a steam-water heat exchanger (800); The steam turbine module (200) includes a steam turbine high-pressure cylinder (210), a steam turbine intermediate-pressure cylinder (220) and a steam turbine low-pressure cylinder (230). The boiler (100) is used to generate high-temperature and high-pressure steam. The boiler (100) is connected to the steam turbine high-pressure cylinder (210) through a main steam pipe (101). The boiler (100) is also connected to the steam turbine intermediate-pressure cylinder (220) through a reheat steam pipe (102). A reheat steam extraction pipe (103) is provided on the reheat steam pipe (102). The output end of the reheat steam extraction pipe (103) is connected to the steam inlet of the steam-molten salt heat exchanger (710) to transfer the heat energy of the steam to the molten salt. The molten salt heat exchanger (710) is provided with a non-condensable gas outlet and is connected to a first non-condensable gas pipeline (711). The non-condensable gas outlet of the steam-molten salt heat exchanger (710) is connected to the steam-water heat exchanger (800) through the first non-condensable gas pipeline (711) to transport uncondensed steam to the steam-water heat exchanger (800) for reuse; the high-pressure cylinder (210) of the steam turbine is connected to the reheater inlet of the boiler (100) through the first exhaust pipe (211), the intermediate-pressure cylinder (220) of the steam turbine is connected to the steam inlet of the low-pressure cylinder (230) of the steam turbine through the second exhaust pipe (221), and the low-pressure cylinder (230) of the steam turbine is connected to the steam inlet of the low-pressure cylinder (230) of the steam turbine through the third exhaust pipe. (231) is connected to the condenser (600), the outlet of the condenser (600) is connected to the low-pressure heater (500) via the condensate pump (610), the high-pressure cylinder (210) of the steam turbine is connected to the first extraction pipe (212), the intermediate-pressure cylinder (220) of the steam turbine is connected to the second extraction pipe (222), and the low-pressure cylinder (230) of the steam turbine is connected to the third extraction pipe (232). The high-pressure cylinder (210) of the steam turbine and the intermediate-pressure cylinder (220) of the steam turbine are connected to the extraction inlet of the high-pressure heater (300) via the first extraction pipe (212) and the second extraction pipe (222), respectively. The low-pressure cylinder (230) of the steam turbine is connected to the extraction inlet of the high-pressure heater (300) via the third extraction pipe. The steam turbine intermediate pressure cylinder (220) is connected to the steam extraction inlet of the low-pressure heater (500), the first outlet water supply pipe (320) of the high-pressure heater (300) is connected to the superheater inlet of the boiler (100), the steam turbine intermediate pressure cylinder (220) is also connected to a fourth steam exhaust pipe (223), the steam turbine intermediate pressure cylinder (220) is connected to the steam extraction inlet of the deaerator (400) through the fourth steam exhaust pipe (223), the high-pressure heater (300) is connected to the steam extraction inlet of the deaerator (400) through the first drain pipe (310), and the low-pressure heater (500) is connected to the steam extraction inlet of the deaerator (400) through the second outlet water supply pipe (520); The molten salt heat exchange system (700) includes a steam-molten salt heat exchanger (710), a molten salt hot tank (720), a molten salt cold tank (730) and a molten salt-feed water heat exchanger (740), wherein the molten salt output end of the molten salt-feed water heat exchanger (740) is connected to the input end of the molten salt cold tank (730) via a pipeline, the output end of the molten salt cold tank (730) is connected to the molten salt input end of the steam-molten salt heat exchanger (710) via a pipeline, the molten salt output end of the steam-molten salt heat exchanger (710) is connected to the input end of the molten salt hot tank (720) via a pipeline, and the output end of the molten salt hot tank (720) is connected to the molten salt input end of the steam-molten salt heat exchanger (710) via a pipeline. The molten salt input end of the molten salt-feed water heat exchanger (740) is connected; the outlet water supply pipe (410) of the deaerator (400) is connected to the high-pressure heater (300) and the molten salt-feed water heat exchanger (740) via the feed water pump (420), the heating water outlet of the molten salt-feed water heat exchanger (740) is connected to the heating water supply pipe (741), and the heating water outlet of the molten salt-feed water heat exchanger (740) is connected to the first outlet water supply pipe (320) through the heating water supply pipe (741), so as to transport the feed water heated in the molten salt-feed water heat exchanger (740) to the boiler (100); The low-pressure heater (500) is connected to the condenser (600) via a second drain pipe (510); the steam-water heat exchanger (800) is provided with a non-condensable gas outlet and is connected to a second non-condensable gas pipe (810); the non-condensable gas outlet of the steam-water heat exchanger (800) is connected to the condenser (600) via the second non-condensable gas pipe (810); The steam-water heat exchanger (800) is connected to the heating network via a heating pipe (801); The heating water supply pipe (741) is connected to a heating bypass pipe (742), the heating bypass pipe (742) is connected to the heating supply pipe (801), and a regulating valve (743) is provided on the heating bypass pipe (742).

2. The heat extraction and supply system for deep peak regulation of thermal power units according to claim 1, characterized in that: The reheat steam extraction pipe (103) is provided with a pressure reducing valve (104).

3. The heat extraction and supply system for deep peak regulation of thermal power units according to claim 1, characterized in that: The steam-water heat exchanger (800) is connected to the deaerator (400) via a drain return pipe (820).

4. The heat extraction and supply system for deep peak regulation of thermal power units according to claim 3 is characterized in that: A pressure water pump (840) is provided on the drain return pipe (820), and the steam-water heat exchanger (800) is further connected to a normal-pressure water pump (830). The inlet of the normal-pressure water pump (830) is connected to a normal-pressure water source, and the outlet of the normal-pressure water pump (830) is connected to the water input end of the steam-water heat exchanger (800) through a pipe, so as to transport normal-pressure water to the steam-water heat exchanger (800).

5. The heat extraction and supply system for deep peak regulation of thermal power units according to claim 1, characterized in that: The steam-molten salt heat exchanger (710) adopts a spiral coil heat exchange structure to improve heat transfer efficiency.

6. A method for operating a heat extraction and heating system for deep peak regulation of a thermal power unit, characterized in that: The heat extraction and supply system for deep peak regulation of a thermal power unit according to any one of claims 1 to 5, wherein the operating method comprises: a. Steam cycle process: a1. High-temperature and high-pressure steam generated by the boiler (100) is transported to the high-pressure cylinder (210) of the steam turbine through the main steam pipe (101); a2. The steam discharged from the high-pressure cylinder (210) of the steam turbine enters the reheater of the boiler (100) through the first exhaust pipe (211) for reheating to form reheated steam; a3. The reheated steam is transported to the steam turbine intermediate pressure cylinder (220) through the reheated steam pipe (102), and the steam discharged from the steam turbine intermediate pressure cylinder (220) is transported to the steam turbine low pressure cylinder (230) through the second steam exhaust pipe (221); a4. The steam exhausted from the low-pressure cylinder (230) of the steam turbine is transported to the condenser (600) through the third exhaust pipe (231) for cooling and recovery; b. Molten salt heat exchange cycle process: b1. The reheated steam is introduced into the steam-molten salt heat exchanger (710) through the reheated steam extraction pipe (103), and the heat energy is transferred to the molten salt; b2. The uncondensed steam in the steam-molten salt heat exchanger (710) is transported through the non-condensable gas outlet and the first non-condensable gas pipeline (711) to the steam-water heat exchanger (800) for further utilization of waste heat; b3. The heated molten salt is transported to the molten salt-feedwater heat exchanger (740) through the molten salt hot tank (720), and the heat is transferred to the feedwater; b4. The cooled molten salt returns to the steam-molten salt heat exchanger (710) through the molten salt cold tank (730), completing the molten salt closed-loop circulation; c. Water supply circulation process: c1. The deaerator (400) deoxygenates the feed water, and the treated feed water is transported to the high-pressure heater (300) and the molten salt-feed water heat exchanger (740) via the feed water pump (420); c2. The feed water heated in the molten salt-feed water heat exchanger (740) is transported to the superheater inlet of the boiler (100) through the heating water supply pipe (741) for further heating; c3. During the peak heating period, part of the heated feed water is directly transported to the heating pipe (801) through the heating bypass pipe (742) to meet the heating demand; c4. The drain generated in the steam-water heat exchanger (800) is transported to the deaerator (400) through the drain return pipe (820), completing a closed-loop cycle.

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