Molten salt energy storage and thermal power unit coupling system

Abstract

The utility model discloses a kind of molten salt energy storage and thermal power generating unit coupling system, coupling system includes: main steam system, including: boiler, high-pressure cylinder, middle-pressure cylinder, low-pressure cylinder, condenser and first circulation pipeline, boiler has first steam pipe, one end of first steam pipe is connected with boiler, the other end is connected with the inlet of high-pressure cylinder, molten salt energy storage system, including: molten salt circulation pipeline, high-temperature molten salt tank, low-temperature molten salt tank and superheater, molten salt circulation pipeline includes: main road, first branch and second branch, first branch and second branch are connected between the both ends of main road, high-temperature molten salt tank is connected on first branch, low-temperature molten salt tank is connected on second branch, superheater has the first flow channel and second flow channel of mutual heat exchange, first flow channel is connected on main road, second flow channel is connected on first steam pipe. According to the coupling system of the utility model, the structural redundancy of respectively setting steam side heat exchanger and molten salt side heat exchanger can be avoided, and the integration of system is improved.

Description

Technical Field

[0001] This utility model relates to the field of coal-fired power generation technology, and in particular to a molten salt energy storage and thermal power unit coupling system. Background Technology

[0002] With the continued advancement of the "dual-carbon" strategy and the increasing proportion of renewable energy, the operating characteristics of the power system have undergone significant changes. The grid connection scale of intermittent power sources such as wind power and photovoltaics is expanding, and the spatial and temporal imbalance between power supply and demand is becoming increasingly prominent. There is an urgent need for power sources with flexible adjustment capabilities to quickly regulate and support system frequency, voltage, and power fluctuations. Against this backdrop, thermal power units, as the main power source in my country's power system, undertake multiple ancillary service functions such as peak shaving, frequency regulation, and backup. Their operating conditions have shifted from long-term stable base load operation to a mode of frequent start-stop and wide-load deep adjustment, posing a huge challenge to traditional thermal power technology.

[0003] Existing thermal power units generally suffer from problems such as slow regulation response, poor efficiency at low loads, high difficulty in deep regulation, and significant losses from frequent start-stop operations. Especially during low-load operation, poor boiler combustion stability and difficulty in controlling main steam temperature can easily lead to thermal fatigue damage to high-temperature components, seriously affecting the unit's lifespan and operational safety. At the same time, the adoption of certain technical means to improve regulation capabilities (such as bypass exhaust and electric heater-assisted start-up) not only increases energy consumption but also significantly reduces the overall economic efficiency of the system.

[0004] In recent years, thermal energy storage technology has become an important way to improve power supply flexibility due to its ability to couple across time periods and energy carriers. Molten salt, as a mature thermal storage medium with high heat capacity, low cost, and a wide operating temperature range (approximately 250~600℃), has been widely used in solar thermal power generation and has the physical basis for deep integration with thermal power systems. However, most current molten salt thermal storage and thermal power coupling schemes construct systems using an "external heat exchanger + parallel process" approach. That is, heat is transferred to the molten salt through a separately installed molten salt heat exchanger by extracting steam from the unit bypass or by electric heating, and the heat energy is released through an independent evaporator when needed. This results in problems such as complex system structure and high equipment investment. Utility Model Content

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a molten salt energy storage and thermal power unit coupling system. This system avoids the structural redundancy of separately setting steam-side heat exchangers and molten salt-side heat exchangers, thereby improving the system's integration. Simultaneously, it allows for direct modular integration and modification of existing thermal power units without altering the main steam flow, thus reducing overall manufacturing costs.

[0006] The molten salt energy storage and thermal power unit coupling system according to this utility model includes: a main steam system, including: a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a condenser, and a first circulation pipeline. The boiler is connected in series on the first circulation pipeline, and the high-pressure cylinder is connected to the steam outlet of the boiler. In the steam flow direction within the first circulation pipeline, the intermediate-pressure cylinder, the low-pressure cylinder, and the condenser are sequentially connected in series on the first circulation pipeline. The boiler has a first steam pipe, one end of which is connected to the boiler, and the other end is connected to the inlet of the high-pressure cylinder. The molten salt energy storage system includes: a molten salt circulation pipeline, a high-temperature molten salt tank, a low-temperature molten salt tank, and a superheater. The molten salt circulation pipeline includes: a main line, a first branch line, and a second branch line. The first branch line and the second branch line are both connected between the two ends of the main line. The high-temperature molten salt tank is connected in series on the... On the first branch, the low-temperature molten salt tank is connected in series on the second branch. The superheater has a first flow channel and a second flow channel that exchange heat with each other. The first flow channel is connected in series on the main line, and the second flow channel is connected in series on the first steam pipe. A third branch has one end connected to the outlet end of the condenser and the other end connected to the inlet end of the second flow channel. An evaporator is connected in series on the third branch and is used to preheat feedwater into saturated steam. A control valve assembly is arranged on the first steam pipe, the molten salt circulation line, and the third branch. The control valve assembly is configured to allow the inlet end of the first flow channel to be selectively connected to either the first branch or the second branch, and to allow the inlet end of the second flow channel to be connected to the first steam pipe and / or the third branch.

[0007] According to the molten salt energy storage and thermal power unit coupling system of this utility model, by setting the superheater with a first flow channel and a second flow channel for mutual heat exchange, this application can realize the bidirectional function of molten salt heat storage and steam reheating with only one superheater, thereby avoiding the structural redundancy of setting separate steam-side heat exchangers and molten salt-side heat exchangers, thus improving the system integration; at the same time, it can directly carry out modular integration and transformation of existing thermal power units without changing the main steam flow, thereby reducing the overall manufacturing cost.

[0008] According to some embodiments of the present invention, the evaporator has a first channel and a second channel, the first channel being connected in series on the third branch, and the second channel being connected in series on the second branch.

[0009] According to some embodiments of the present invention, the first steam pipe has a main pipe, a first bypass, and a second bypass. The second flow channel is connected in series on the main pipe. One end of the main pipe is connected to the boiler. One end of the first bypass and one end of the second bypass are both connected to the other end of the main pipe. The other end of the first bypass is connected to the high-pressure cylinder, and the other end of the second bypass is connected to the low-pressure cylinder. The control valve assembly includes a first regulating valve, a first control valve, a second control valve, and a third control valve. The first regulating valve is connected in series on the main pipe and arranged at the inlet end of the second flow channel. The first control valve is connected in series on the main pipe and arranged at the outlet end of the second flow channel. The second control valve is connected in series on the first bypass, and the third control valve is connected in series on the second bypass.

[0010] According to some embodiments of the present invention, the control valve assembly further includes: a fourth control valve, a fifth control valve, a sixth control valve, a seventh control valve, and an eighth control valve. The fourth control valve and the fifth control valve are respectively connected to the inlet and outlet ends of the high-temperature molten salt tank. The sixth control valve and the seventh control valve are respectively connected to the inlet and outlet ends of the low-temperature molten salt tank. The second channel is arranged between the sixth control valve and the inlet end of the low-temperature molten salt tank. The eighth control valve is connected in series on the third branch and is arranged at the outlet end of the first channel.

[0011] According to some embodiments of the present invention, the coupling system further includes a circulating water pump connected in series on the third branch.

[0012] According to some embodiments of the present invention, the molten salt energy storage system further includes: a temperature monitoring device and a liquid level control device. The temperature monitoring device and the liquid level control device are respectively installed on the high-temperature molten salt tank and the low-temperature molten salt tank. The temperature monitoring device is used to monitor the temperature of the molten salt in the high-temperature molten salt tank and the low-temperature molten salt tank in real time, and the liquid level control device is used to detect the liquid level of the molten salt in the high-temperature molten salt tank and the low-temperature molten salt tank in real time.

[0013] According to some embodiments of the present invention, the coupling system further includes: a temperature difference detection device, which is disposed at the outlet end of the superheater and the outlet end of the evaporator, for detecting the temperature difference between the inlet and outlet of the superheater and the evaporator.

[0014] According to some embodiments of the present invention, the coupling system further includes: a flow detection device, which is disposed at the outlet end of the superheater and the outlet end of the evaporator, for detecting the flow rate at the outlet ends of the superheater and the evaporator.

[0015] According to some embodiments of the present invention, the coupling system further includes an alarm device, which is electrically connected to the temperature difference detection device and the flow detection device, and is configured to issue an alarm when the temperature difference exceeds a preset temperature difference and / or the flow exceeds a preset flow.

[0016] According to some embodiments of the present invention, the molten salt energy storage system further includes: a low-temperature molten salt pump and a high-temperature molten salt pump, wherein the low-temperature molten salt pump is connected in series on the second branch and the high-temperature molten salt pump is connected in series on the first branch.

[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the coupling system according to an embodiment of the present utility model.

[0019] Figure label: 100. Coupled system; 10. Main steam system; 11. Boiler; 121. High-pressure cylinder; 122. Intermediate-pressure cylinder; 123. Low-pressure cylinder; 13. Condenser; 14. First circulation pipeline; 15. Condensate pump; 161. Low-pressure heater; 162. High-pressure heater; 17. Deaerator; 18. Water pump; 19. First steam pipe; 191. Main pipe; 192. First bypass; 193. Second bypass; 20. Molten salt energy storage system; 21. Molten salt circulation pipeline; 211. Main pipeline; 212. First branch pipeline; 213. Second branch pipeline; 22. High-temperature molten salt tank; 23. Low-temperature molten salt tank; 24. Superheater; 25. Low-temperature molten salt pump; 26. High-temperature molten salt pump; 30. The third branch road; 40. Evaporator; 50. Control valve assembly; 51. First regulating valve; 52. First control valve; 53. Second control valve; 54. Third control valve; 55. Fourth control valve; 56. Fifth control valve; 57. Sixth control valve; 58. Seventh control valve; 59. Eighth control valve; 60. Circulating water pump. Detailed Implementation

[0020] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0021] The following is for reference. Figure 1 This invention describes a molten salt energy storage and thermal power unit coupling system 100 according to an embodiment of the present invention.

[0022] like Figure 1 As shown, the molten salt energy storage and thermal power unit coupling system 100 according to an embodiment of the present invention includes: a main steam system 10, a molten salt energy storage system 20, a third branch 30, an evaporator 40, and a control valve assembly 50.

[0023] The main steam system 10 includes a boiler 11, a high-pressure cylinder 121, a medium-pressure cylinder 122, a low-pressure cylinder 123, a condenser 13, and a first circulation pipeline 14. The boiler 11 is connected in series to the first circulation pipeline 14. The high-pressure cylinder 121 is connected to the steam outlet of the boiler 11. In the direction of steam flow in the first circulation pipeline 14, the medium-pressure cylinder 122, the low-pressure cylinder 123, and the condenser 13 are connected in series to the first circulation pipeline. The boiler 11 has a first steam pipe 19. One end of the first steam pipe 19 is connected to the boiler 11, and the other end is connected to the inlet of the high-pressure cylinder 121.

[0024] Specifically, the high-temperature and high-pressure steam generated by the combustion of the boiler 11 can enter the high-pressure cylinder 121, intermediate-pressure cylinder 122 and low-pressure cylinder 123 of the steam turbine in sequence through the first circulation pipeline 14 to expand and do work. Alternatively, it can enter the high-pressure cylinder 121 through the first steam pipe 19, and then enter the intermediate-pressure cylinder 122 and low-pressure cylinder 123 in sequence to do work, so as to drive the generator to output electrical energy.

[0025] It should be noted that the main steam system 10 also includes: a condensate pump 15, a low-pressure heater 161, a deaerator 17, a water pump 18, and a high-pressure heater 162. The condensate pump 15 is connected to the outlet end of the condenser. In the direction of liquid flow in the first circulation pipe 14, the condensate pump 15, the low-pressure heater 161, the deaerator 17, the water pump 18, and the high-pressure heater 162 are connected in series on the first circulation pipe. That is to say, the steam after working by the high-pressure cylinder 121, the intermediate-pressure cylinder 122, and the low-pressure cylinder 123 is condensed into condensate by the condenser 13, and can be pumped by the condensate pump 15 to the low-pressure heater 161 and the deaerator 17 for heating and deoxygenation. Then, it is pressurized by the feedwater pump 18 and sent to the high-pressure heater 162 for further heating before returning to the boiler 11. This ensures that the water returning to the coal-fired boiler 11 has a certain temperature, thereby increasing the steam generation rate of the coal-fired boiler 11 and achieving a faster load change rate.

[0026] The molten salt energy storage system 20 includes: a molten salt circulation pipeline 21, a high-temperature molten salt tank 22, a low-temperature molten salt tank 23, and a superheater 24. The molten salt circulation pipeline 21 includes: a main pipeline 211, a first branch pipeline 212, and a second branch pipeline 213. The first branch pipeline 212 and the second branch pipeline 213 are both connected between the two ends of the main pipeline 211. The high-temperature molten salt tank 22 is connected in series with the first branch pipeline 212, and the low-temperature molten salt tank 23 is connected in series with the second branch pipeline 213. The superheater 24 has a first flow channel and a second flow channel for mutual heat exchange. The first flow channel is connected in series with the main pipeline 211, and the second flow channel is connected in series with the first steam pipe. 19; one end of the third branch 30 is connected to the outlet end of the condenser 13, and the other end of the third branch 30 is connected to the inlet end of the second flow channel; the evaporator 40 is connected in series on the third branch 30, and the evaporator 40 is used to preheat the feedwater into saturated steam; the control valve assembly 50 is arranged on the first steam pipe 19, the molten salt circulation pipe 21 and the third branch 30, and the control valve assembly 50 is configured to connect the inlet end of the first flow channel to the first branch 212 or the second branch 213, and to connect the inlet end of the second flow channel to the first steam pipe 19 and / or the third branch 30.

[0027] Among them, the high-temperature molten salt tank 22 is mainly used to store high-temperature molten salt; the low-temperature molten salt tank 23 is mainly used to store low-temperature molten salt; the molten salt circulation pipeline 21 is mainly used for the flow of molten salt; the superheater 24 is mainly used to realize the heat exchange between the molten salt flowing in the main pipeline 211 and the steam in the first steam pipe 19; the third branch pipeline 30 is mainly used to transfer the condensate formed by the steam after the steam turbine has done work to the evaporator 40, and then after being processed by the evaporator 40, it is transferred to the second flow channel to exchange heat with the molten salt in the first flow channel.

[0028] "The molten salt circulation pipeline 21 includes: a main pipeline 211, a first branch pipeline 212, and a second branch pipeline 213. The first branch pipeline 212 and the second branch pipeline 213 are both connected between the two ends of the main pipeline 211. The high-temperature molten salt tank 22 is connected in series on the first branch pipeline 212, and the low-temperature molten salt tank 23 is connected in series on the second branch pipeline 213." It can be understood that the high-temperature molten salt tank 22 and the low-temperature molten salt tank 23 are connected to the two ends of the main pipeline 211 through parallel branches, forming a recyclable molten salt energy storage loop.

[0029] "The superheater 24 has a first flow channel and a second flow channel that exchange heat with each other. The first flow channel is connected in series with the main flow 211, and the second flow channel is connected in series with the first steam pipe 19." It can be understood that only the molten salt flowing through the main flow 211 can exchange heat with the steam in the second flow channel.

[0030] "The control valve assembly 50 is configured to connect the inlet of the first flow channel to either the first branch 212 or the second branch 213, and to connect the inlet of the second flow channel to the first steam pipe 19 and / or the third branch 30." It can be understood that the control valve assembly 50 allows molten salt at one temperature to pass through the first flow channel at any given time, and allows steam to flow through the second flow channel at any given time, either only the steam in the first steam pipe 19, only the steam in the third branch 30, or both the first steam pipe 19 and the third branch 30.

[0031] Specifically, when the thermal power unit is operating at low load, the power grid is in a low-load period, or the steam flow of boiler 11 needs to be adjusted, the coupling system 100 enters the heat storage mode. At this time, the control valve assembly 50 controls the inlet end of the first flow channel to be connected to the second branch 213, and the inlet end of the second flow channel is only connected to the first steam pipe 19. That is, the steam of boiler 11 exchanges heat with the low-temperature molten salt to heat the low-temperature molten salt, and then the heated low-temperature molten salt is transported to the high-temperature molten salt tank 22 for storage.

[0032] When the power grid is at its peak, or when thermal power units need to start up quickly or provide peak-shaving support, the coupling system 100 enters the heat release mode. At this time, the control valve assembly 50 controls the inlet end of the first flow channel to be connected to the first branch 212, and the inlet end of the second flow channel to be connected to the third branch 30 and / or the first steam pipe 19. That is, the saturated steam and boiler 11 steam are heated by high-temperature molten salt so that the saturated steam and boiler 11 steam are further heated to form reheated steam, and then enter the high-pressure cylinder 121 to expand and do work.

[0033] Therefore, it can be understood that the coupling system 100 in this embodiment can support three operating modes. The first is the conventional operating mode: the molten salt energy storage system 20 does not participate in the system operation at all; only the main steam system 10 operates. The main steam enters the first circulation pipeline 14 and sequentially passes through the high-pressure cylinder 121, the intermediate-pressure cylinder 122, and the low-pressure cylinder 123 to perform work, and is condensed and recovered after being powered by each stage of the steam turbine. The second is the thermal storage operating mode: when the system electrical load is low, the grid is disconnected, or the electricity price is low, the low-temperature molten salt can be controlled by the control valve assembly 50 to absorb heat from the main steam of the boiler 11 through the shared superheater 24 and then flow into the high-temperature molten salt tank, thereby achieving decoupled thermal and electrical thermal storage. Third, the heat release operation mode: In the scenarios of peak power load, rapid unit start-up or reheat peak shaving, the high temperature molten salt can be sent to the superheater 24 to release heat to the steam system by controlling the control valve assembly 50. At the same time, the feedwater is preheated and vaporized by the evaporator 40 to form high-quality reheat steam that enters the steam turbine to do work, thereby realizing the orderly release of thermal energy and auxiliary peak shaving.

[0034] Furthermore, in existing technologies, most molten salt thermal energy storage and thermal power coupling schemes construct systems using an "external heat exchanger + parallel process" approach. This means that heat is transferred to the molten salt through a separately installed molten salt heat exchanger via steam extraction from the unit bypass or electric heating, and the heat energy is released through a separate evaporator when needed. This results in problems such as complex system structure and high equipment investment.

[0035] This application achieves both molten salt heat storage and steam reheating functions using only one superheater 24, evaporator 40, and control valve assembly 50. This avoids the structural redundancy of setting up separate steam-side and molten salt-side heat exchangers, thereby improving the system integration. In addition, since the control valve assembly 50, superheater 24, and evaporator 40 are not directly designed on the main steam system 10, existing thermal power units can be directly modularly integrated and modified without changing the main steam flow, thereby reducing the overall manufacturing cost.

[0036] According to the molten salt energy storage and thermal power unit coupling system 100 of this utility model, by setting the superheater 24 to have a first flow channel and a second flow channel for mutual heat exchange, this application can realize the bidirectional function of molten salt heat storage and steam reheating with only one superheater 24, thereby avoiding the structural redundancy of setting separate steam-side heat exchangers and molten salt-side heat exchangers, thus improving the system integration; at the same time, it can directly carry out modular integration and transformation of existing thermal power units without changing the main steam flow, thereby reducing the overall manufacturing cost.

[0037] According to some embodiments of this utility model, the evaporator 40 has a first channel and a second channel, the first channel being connected in series to the third branch 30, and the second channel being connected in series to the second branch 213. It is understood that the evaporator 40 performs heat exchange through molten salt after heat exchange, which further enhances the utilization of thermal energy, thereby further improving energy efficiency and system economy.

[0038] According to some embodiments of this utility model, such as Figure 1As shown, the first steam pipe 19 has a main pipe 191, a first bypass 192 and a second bypass 193. The second flow channel is connected in series with the main pipe 191. One end of the main pipe 191 is connected to the boiler 11. One end of the first bypass 192 and one end of the second bypass 193 are both connected to the main pipe 191. The other end of the first bypass 192 is connected to the high-pressure cylinder 121, and the other end of the second bypass 193 is connected to the low-pressure cylinder 123. The control valve assembly 50 includes a first regulating valve 51, a first control valve 52, a second control valve 53 and a third control valve 54. The first regulating valve 51 is connected in series with the main pipe 191 and arranged at the inlet end of the second flow channel. The first control valve 52 is connected in series with the main pipe 191 and arranged at the outlet end of the second flow channel. The second control valve 53 is connected in series with the first bypass 192, and the third control valve 54 is connected in series with the second bypass 193. The first regulating valve 51 and the first control valve 52 are mainly used to control the opening and closing of the main pipe 191 so that the main pipe 191 is connected to the second flow channel; the second control valve 53 is mainly used to control the opening and closing of the first bypass 192; and the third control valve 54 is mainly used to control the opening and closing of the second bypass 193.

[0039] Specifically, when the coupling system 100 of this embodiment is running in the normal mode, the first regulating valve 51 blocks the main pipe 191, preventing steam from flowing through the main pipe 191. That is, the steam from the boiler 11 can only flow through the main steam system 10. When the coupling system 100 is running in the heat storage mode, the first regulating valve 51 and the first control valve 52 are both open to keep the main pipe 191 connected. The second control valve 53 and the third control valve 54 are both closed to disconnect the first bypass 192 and the second bypass 193 from the main pipe 191. When the coupling system 100 is running in the heat release mode, the first regulating valve 51, the first control valve 52, and the second control valve 53 are all open to allow the heat-exchanged steam to enter the high-pressure cylinder 121 to do work.

[0040] According to some embodiments of this utility model, such as Figure 1 As shown, the control valve assembly 50 further includes: a fourth control valve 55, a fifth control valve 56, a sixth control valve 57, a seventh control valve 58, and an eighth control valve 59. The fourth control valve 55 and the fifth control valve 56 are respectively connected to the inlet and outlet ends of the high-temperature molten salt tank 22, and the sixth control valve 57 and the seventh control valve 58 are respectively connected to the inlet and outlet ends of the low-temperature molten salt tank 23. The second channel is arranged between the sixth control valve 57 and the inlet end of the low-temperature molten salt tank 23. The eighth control valve 59 is connected in series on the third branch 30 and is arranged at the outlet end of the first channel.

[0041] Specifically, the fourth control valve 55 and the fifth control valve 56 are mainly used to control the on / off state of the first branch 212. The fourth control valve 55 is arranged at the inlet end of the high-temperature molten salt tank 22 to connect or disconnect the high-temperature molten salt tank 22 from the outlet end of the first flow channel. The fifth control valve 56 is arranged at the outlet end of the high-temperature molten salt tank 22 to connect or disconnect the high-temperature molten salt tank 22 from the inlet end of the first flow channel. The sixth control valve 57 and the seventh control valve 58 are mainly used to control the on / off state of the second branch 213. The sixth control valve 57 is arranged at the inlet end of the low-temperature molten salt tank 23 to connect or disconnect the low-temperature molten salt tank 23 from the outlet end of the first flow channel. The seventh control valve 58 is arranged at the outlet end of the low-temperature molten salt tank 23 to connect or disconnect the low-temperature molten salt tank 23 from the inlet end of the first flow channel. The eighth control valve 59 is mainly used to control the on / off state of the third branch 30 to connect and disconnect the first channel from the second flow channel.

[0042] The following is based on Figure 1 The diagram illustrates the working process of this application in three working modes.

[0043] In normal operation mode, the molten salt thermal storage system is in a non-working state, and all control valves and the first regulating valve 51 remain closed. Only the main steam system 10 participates in power generation. At this time, the high-temperature and high-pressure steam generated by the combustion of the boiler 11 enters the first circulation pipeline 14 and sequentially enters the high-pressure cylinder 121, intermediate-pressure cylinder 122 and low-pressure cylinder 123 of the steam turbine to expand and do work to drive the generator to output electrical energy. The exhaust steam discharged from the low-pressure cylinder 123 is cooled into condensate by the condenser 13, and then sent by the condensate pump 15 to the low-pressure heater 161 and deaerator 17 for heating and deoxygenation. After that, it is pressurized by the feedwater pump 18 and sent to the high-pressure heater 162 for further heating before returning to the boiler 11.

[0044] In the thermal storage operation mode, the system enters the condition of storing thermal energy in molten salt. At this time, the first regulating valve 51, the first control valve 52, the third control valve 54, the fourth control valve 55, and the seventh control valve 58 are in the open state, while the other control valves are in the closed state. At this time, the main steam of boiler 11 enters the second flow channel through the main pipe 191, and the low-temperature molten salt enters the first flow channel through the second branch 213 to exchange heat with the main steam of boiler 11. After absorbing heat, the temperature of the low-temperature molten salt rises, and then it enters the high-temperature molten salt tank 22 for storage through the fourth control valve 55. The main steam after heat exchange enters the low-pressure cylinder 123 through the second bypass 193 to do work.

[0045] In heat release operation mode, the system releases heat energy from high-temperature molten salt to the steam system. At this time, the first regulating valve 51, the first control valve 52, the second control valve 53, the fifth control valve 56, the sixth control valve 57, and the eighth control valve 59 are all in the open state, while the other valves are in the closed state. The high-temperature molten salt flows out of the high-temperature molten salt storage tank and is sent to the common superheater 24 via the fifth control valve 56 to release heat, which is used to heat the mixed steam from the saturated steam coming out of the evaporator 40 and the main steam coming out of the boiler 11. The heated superheated steam is then sent to the high-pressure cylinder 121 of the steam turbine via the second control valve 53 for expansion and work. Additionally, the molten salt, after heat exchange, flows back into the evaporator 40 via the sixth control valve 57 for further heat exchange, and then flows back to the low-temperature molten salt storage tank, completing a closed-loop cycle.

[0046] It should be noted that the other end of the main pipe 191 is connected to external equipment, so that the remaining heat after the heat storage is completed can be reused, thereby further improving the overall energy efficiency of the system.

[0047] According to some embodiments of this utility model, such as Figure 1 As shown, the system also includes a circulating water pump 60, which is connected in series to the third branch 30. Specifically, the circulating water pump 60 is used to send a portion of the condensate pump 18 in the first circulating pipeline 14 to the evaporator 40, providing driving force for the flow of condensate in the third branch 30. This allows the steam after it has done work in the high-pressure cylinder 121, the medium-pressure cylinder 122, and the low-pressure cylinder 123 to be reused, thereby reducing energy loss, improving energy utilization, and enhancing the system's economy.

[0048] According to some embodiments of this utility model, the molten salt energy storage system 20 further includes a temperature monitoring device and a liquid level control device. Both the high-temperature molten salt tank 22 and the low-temperature molten salt tank 23 are equipped with temperature monitoring devices and liquid level control devices. The temperature monitoring device is used to monitor the temperature of the molten salt in the high-temperature molten salt tank 22 and the low-temperature molten salt tank 23 in real time, and the liquid level control device is used to detect the liquid level of the molten salt in the high-temperature molten salt tank 22 and the low-temperature molten salt tank 23 in real time. This effectively avoids overcharging and over-discharging, thereby ensuring the safe and stable operation of the entire system.

[0049] According to some embodiments of this utility model, the coupling system 100 further includes a temperature difference detection device, which is disposed at the outlet end of the superheater 24 and the outlet end of the evaporator 40, and is used to detect the temperature difference between the inlet and outlet of the superheater 24 and the evaporator 40. In this way, the temperature difference between the inlet and outlet of the superheater 24 and the evaporator 40 can be detected in real time, thereby ensuring the normal operation of the superheater 24 and the evaporator 40.

[0050] According to some embodiments of this utility model, the coupling system further includes a flow detection device, which is located at the outlet end of the superheater 24 and the outlet end of the evaporator 40, for detecting the flow rate at the outlet ends of the superheater 24 and the evaporator 40. This allows for real-time detection of the flow rate at the outlets of the superheater 24 and the evaporator 40, enabling timely detection of any abnormal operation of the superheater 24 and / or the evaporator 40, thereby improving the overall system's operational safety. Simultaneously, based on the observed real-time flow rates at the outlets of the superheater 24 and the evaporator 40, the outlet flow rate can be adjusted promptly to ensure complete heat exchange.

[0051] According to some embodiments of this utility model, the coupling system 100 further includes an alarm device, which is electrically connected to a temperature difference detection device and a flow detection device. The alarm device is configured to issue an alarm when the temperature difference exceeds a preset temperature difference and / or the flow rate exceeds a preset flow rate. This allows staff to promptly detect abnormal states occurring during the operation of the molten salt energy storage and thermal power unit coupling system 100, enabling timely response and handling, thereby reducing other problems caused by system anomalies.

[0052] It is understood that in this embodiment, the alarm device can be set to issue an alarm when the temperature difference exceeds a preset temperature difference, or when the flow rate exceeds a preset flow rate, or when both the temperature difference and the flow rate exceed a preset flow rate.

[0053] It should be noted that the alarm can be an audible alarm, a visual alarm, or a combination of both; there are no restrictions here.

[0054] Optionally, the control valve assembly 50 also includes an electric actuator electrically connected to the control valve. The system also includes a central controller electrically connected to the electric actuator. The central controller can control the start and stop of the control valve through the electric actuator, thereby enabling automatic switching between modes and rapid shutdown protection in abnormal situations.

[0055] Optionally, the molten salt circulation pipeline 21 is made of high-temperature resistant and corrosion-resistant materials, which can prevent crystallization and leakage inside the pipeline, thereby improving the safety of the entire system operation.

[0056] According to some embodiments of this utility model, such as Figure 1 As shown, the molten salt energy storage system 20 also includes a cryogenic molten salt pump 25 and a high-temperature molten salt pump 26. The cryogenic molten salt pump 25 is connected in series on the second branch 213, and the high-temperature molten salt pump 26 is connected in series on the first branch 212. Specifically, the cryogenic molten salt tank 23 provides driving force for the flow of cryogenic molten salt, and the high-temperature molten salt pump 26 provides driving force for the flow channel of high-temperature molten salt, so that the molten salt energy storage system 20 can realize heat storage and heat release.

[0057] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0058] Furthermore, 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0059] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0060] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0061] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A molten salt energy storage and thermal power unit coupling system (100), characterized in that, include: The main steam system (10) includes: a boiler (11), a high-pressure cylinder (121), an intermediate-pressure cylinder (122), a low-pressure cylinder (123), a condenser (13), and a first circulation pipeline (14). The boiler (11) is connected in series to the first circulation pipeline (14). The high-pressure cylinder (121) is connected to the steam outlet of the boiler (11). In the direction of steam flow in the first circulation pipeline (14), the intermediate-pressure cylinder (122), the low-pressure cylinder (123), and the condenser (13) are connected in series to the first circulation pipeline. The boiler (11) has a first steam pipe (19), one end of which is connected to the boiler (11) and the other end is connected to the inlet of the high-pressure cylinder (121). The molten salt energy storage system (20) includes: a molten salt circulation pipeline (21), a high-temperature molten salt tank (22), a low-temperature molten salt tank (23), and a superheater (24). The molten salt circulation pipeline (21) includes: a main pipeline (211), a first branch pipeline (212), and a second branch pipeline (213). The first branch pipeline (212) and the second branch pipeline (213) are both connected between the two ends of the main pipeline (211). The high-temperature molten salt tank (22) is connected in series on the first branch pipeline (212), and the low-temperature molten salt tank (23) is connected in series on the second branch pipeline (213). The superheater (24) has a first flow channel and a second flow channel that exchange heat with each other. The first flow channel is connected in series on the main pipeline (211), and the second flow channel is connected in series on the first steam pipe (19). The third branch (30) has one end connected to the outlet end of the condenser (13) and the other end connected to the inlet end of the second flow channel; Evaporator (40), which is connected in series on the third branch (30), is used to preheat feedwater into saturated steam; A control valve assembly (50) is arranged on the first steam pipe (19), the molten salt circulation line (21), and the third branch (30). The control valve assembly (50) is configured to connect the inlet end of the first flow channel to either the first branch (212) or the second branch (213), and to connect the inlet end of the second flow channel to the first steam pipe (19) and / or the third branch (30).

2. The molten salt energy storage and thermal power unit coupling system (100) according to claim 1, characterized in that, The evaporator (40) has a first channel and a second channel, the first channel being connected in series to the third branch (30) and the second channel being connected in series to the second branch (213).

3. The molten salt energy storage and thermal power unit coupling system (100) according to claim 2, characterized in that, The first steam pipe (19) has a main pipe (191), a first bypass (192), and a second bypass (193). The second flow channel is connected in series with the main pipe (191). One end of the main pipe (191) is connected to the boiler (11). One end of the first bypass (192) and one end of the second bypass (193) are both connected to the other end of the main pipe (191). The other end of the first bypass (192) is connected to the high-pressure cylinder (121), and the other end of the second bypass (193) is connected to the low-pressure cylinder (123). The control valve assembly (50) includes: a first regulating valve (51), a first control valve (52), a second control valve (53), and a third control valve (54). The first regulating valve (51) is connected in series on the main pipe (191) and arranged at the inlet end of the second flow channel. The first control valve (52) is connected in series on the main pipe (191) and arranged at the outlet end of the second flow channel. The second control valve (53) is connected in series on the first bypass (192). The third control valve (54) is connected in series on the second bypass (193).

4. The molten salt energy storage and thermal power unit coupling system (100) according to claim 3, characterized in that, The control valve assembly (50) further includes: a fourth control valve (55), a fifth control valve (56), a sixth control valve (57), a seventh control valve (58), and an eighth control valve (59). The fourth control valve (55) and the fifth control valve (56) are respectively connected to the inlet and outlet of the high-temperature molten salt tank (22). The sixth control valve (57) and the seventh control valve (58) are respectively connected to the inlet and outlet of the low-temperature molten salt tank (23). The second channel is arranged between the sixth control valve (57) and the inlet of the low-temperature molten salt tank (23). The eighth control valve (59) is connected in series on the third branch (30) and arranged at the outlet of the first channel.

5. The molten salt energy storage and thermal power unit coupling system (100) according to claim 1, characterized in that, Also includes: A circulating water pump (60) is connected in series on the third branch (30).

6. The molten salt energy storage and thermal power unit coupling system (100) according to claim 1, characterized in that, The molten salt energy storage system (20) further includes a temperature monitoring device and a liquid level control device. The temperature monitoring device and the liquid level control device are installed on both the high-temperature molten salt tank (22) and the low-temperature molten salt tank (23). The temperature monitoring device is used to monitor the temperature of the molten salt in the high-temperature molten salt tank (22) and the low-temperature molten salt tank (23) in real time. The liquid level control device is used to detect the liquid level of the molten salt in the high-temperature molten salt tank (22) and the low-temperature molten salt tank (23) in real time.

7. The molten salt energy storage and thermal power unit coupling system (100) according to claim 1, characterized in that, Also includes: A temperature difference detection device is provided at the outlet end of the superheater (24) and the outlet end of the evaporator (40) to detect the temperature difference between the inlet and outlet of the superheater (24) and the evaporator (40).

8. The molten salt energy storage and thermal power unit coupling system (100) according to claim 7, characterized in that, It also includes a flow detection device, which is located at the outlet end of the superheater (24) and the outlet end of the evaporator (40) for detecting the flow rate at the outlet ends of the superheater (24) and the evaporator (40).

9. The molten salt energy storage and thermal power unit coupling system (100) according to claim 8, characterized in that, Also includes: An alarm device is electrically connected to the temperature difference detection device and the flow detection device, and the alarm device is configured to issue an alarm when the temperature difference exceeds a preset temperature difference and / or the flow exceeds a preset flow.

10. The molten salt energy storage and thermal power unit coupling system (100) according to claim 1, characterized in that, The molten salt energy storage system (20) further includes a low-temperature molten salt pump (25) and a high-temperature molten salt pump (26), wherein the low-temperature molten salt pump (25) is connected in series on the second branch (213) and the high-temperature molten salt pump (26) is connected in series on the first branch (212).

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