Fused salt energy storage and heat supply system based on coal-electricity coupling and control method

Abstract

The invention relates to an electric heating unit system, in particular to a fused salt energy storage heat supply system based on coal-electricity coupling and a control method. The system comprises a boiler module, a steam turbine module, a molten salt module and a steam reheater which are used for converting the reheat steam amount. Wherein the second fused salt heating unit is used for heating fused salt through second reheat steam so as to complete secondary steam heat storage, and the second fused salt heating unit is connected with a heat supply pipe network so as to supply heat to the outside; through a main steam shunting and multi-stage heat storage structure, high-grade steam preferentially completes power generation circulation, waste heat enters a fused salt system to be stored in a graded mode, exhausted steam is reheated through stored high-temperature fused salt, in addition, independent storage and on-demand release of heat energy of different qualities are achieved through a double-unit structure of a fused salt module, and the energy-saving effect is achieved. And grade loss caused by energy mixing is avoided, and the problem that in the prior art, the exhaust steam temperature is lower than the temperature parameter needed by actual heat supply is solved through gradient utilization of energy.

Description

Technical Field

[0001] This invention relates to electric heating unit systems, and more particularly to a molten salt energy storage heating system and control method based on coal-electric coupling. Background Technology

[0002] Molten salt thermal energy storage systems are considered a key technological approach to enhance the flexibility of coal-fired power units due to their large capacity, long cycle time, and high stability. Existing technologies have integrated molten salt thermal energy storage systems into coal-fired power units, primarily utilizing main steam or reheat steam for thermal storage. When needed, the system releases the stored heat energy, typically through molten salt heat exchange, to directly generate steam that meets user parameter requirements for external heating.

[0003] However, existing coal-fired power coupled molten salt thermal energy storage technologies have significant limitations, the core issue being insufficient energy conversion efficiency and value extraction. In the heat release process, existing systems generally adopt a mode of directly generating heating steam, achieving only heat-to-heat conversion. After storage in the molten salt system, the energy is ultimately output only as heating steam, completely wasting the work-capable capacity of high-quality thermal energy and failing to achieve efficient, cascaded energy utilization.

[0004] Furthermore, when using back-pressure units for combined heat and power (CHP), existing technologies often adjust the exhaust pressure to be close to the heating pressure in order to achieve the best power generation efficiency. This often results in the exhaust temperature being lower than the actual heating temperature required, which cannot directly meet the industrial heating demand and leads to inadequate energy utilization or the need for additional heating. Summary of the Invention

[0005] The main objective of this invention is to provide a molten salt energy storage heating system and control method based on coal-electricity coupling, aiming to solve the problem that the exhaust steam temperature is lower than the actual heating temperature parameter required in the prior art.

[0006] To achieve the above objectives, the present invention provides a molten salt energy storage heating system based on coal-electricity coupling. The system is connected to a heating network to provide external heating. The system includes: A boiler module for generating main steam, the main steam including a first steam component and a second steam component; A steam turbine module is connected to the boiler module. The steam turbine module includes a first steam turbine and a second steam turbine. The first steam turbine is used to do work using a first steam component. The first steam component after doing work returns to the boiler module and generates first reheat steam. The second steam turbine is used to do work using a second reheat steam. The molten salt module includes a first molten salt heating unit and a second molten salt heating unit. The first molten salt heating unit is used to exchange heat with a second steam component to generate a second reheated steam. The first reheated steam and the second reheated steam form a reheated steam quantity to complete the first-stage steam heat storage. Steam reheater is used to convert the amount of reheat steam. The second molten salt heating unit is used to heat molten salt with the second reheat steam to complete the secondary steam heat storage. The second molten salt heating unit is connected to the heating network to provide external heat. The molten salt module further includes a first molten salt unit and a second molten salt unit. The second molten salt unit is used to convert the heat of the first molten salt heating unit and the second molten salt heating unit to store molten salt in the first molten salt unit to complete the first-stage molten salt heat storage and the second-stage molten salt heat storage. The first molten salt unit is also used to release heat to the outside.

[0007] Optionally, the system further includes: regulating valve VI, first pressure regulating valve, and electric valve IV, wherein the regulating valve VI, first pressure regulating valve, first molten salt heating unit, and electric valve IV are sequentially connected to the boiler module to form a primary steam heat storage path, and the second steam component passes through the primary steam heat storage path and then combines with the first steam component to form reheat steam.

[0008] Optionally, the system further includes: regulating valve VII, second pressure regulating valve, electric valve I, measuring module, and electric valve III, wherein the regulating valve VII, second pressure regulating valve, and second molten salt heating unit are sequentially connected to the boiler module to form a secondary steam heat storage path, and the secondary steam heat storage path is also sequentially connected to electric valve I, measuring module, and electric valve III to form a heating path.

[0009] Optionally, the system further includes a first molten salt pump and a regulating valve I, wherein the first molten salt pump, the regulating valve I, and the first molten salt heating unit are sequentially connected to a second molten salt unit to form a primary molten salt heat storage path, and the primary molten salt heat storage path is connected to the first molten salt unit.

[0010] Optionally, the system further includes a regulating valve II, wherein the first molten salt pump, the regulating valve II, and the second molten salt heating unit are sequentially connected to the second molten salt unit to form a secondary molten salt heat storage path, and the secondary molten salt heat storage path is connected to the first molten salt unit.

[0011] Optionally, the system further includes a second molten salt pump, a regulating valve III, and a steam generator, wherein the second molten salt pump, the regulating valve III, and the steam generator are sequentially connected to the first molten salt unit to form a primary molten salt heat release path, and the primary molten salt heat release path is connected to the second molten salt unit.

[0012] Optionally, the system further includes a regulating valve IV and a steam reheater, wherein the second molten salt pump, the regulating valve IV, and the steam reheater are sequentially connected to the first molten salt unit to form a secondary molten salt heat release path, and the secondary molten salt heat release path is connected to the second molten salt unit.

[0013] Optionally, the system further includes a deaerator and a back pressure unit. The deaerator is connected to a feedwater pump, which is connected to a regulating valve V and to the steam generator via the regulating valve V. The steam generator is also used to generate thermo-pressure steam and is also connected to the back pressure unit to generate back pressure steam.

[0014] Optionally, the system further includes electric valve II and electric valve III. After the back pressure machine is connected to the steam reheater, it is also connected to electric valve II, the measurement module and electric valve III in sequence to form a secondary steam heat release.

[0015] A control method for a molten salt energy storage heating system based on coal-electricity coupling, the control method comprising the following steps: Set the amount of steam for heating; The boiler module generates the main steam volume, and the second steam component is controlled to enter the first molten salt heating unit to heat the molten salt to the set temperature, generating the second reheat steam to complete the first-stage steam heat storage. The second molten salt unit controls the conversion of heat between the first molten salt heating unit and the second molten salt heating unit to store molten salt in the first molten salt unit, thus completing the first-stage and second-stage molten salt heat storage. The second molten salt heating unit is controlled to heat the molten salt using the second reheat steam to complete the secondary steam thermal storage. The molten salt from the first molten salt unit is controlled to return to the second molten salt unit to complete the primary and secondary molten salt heat release. The steam generator is controlled to produce high-temperature and high-pressure steam, and the back pressure machine is controlled to produce back-pressure steam, so as to complete the first-stage steam heat release. Control the steam reheater to complete the secondary steam heat release.

[0016] This invention proposes a molten salt energy storage heating system and control method based on coal-electricity coupling. Through main steam diversion and multi-stage thermal storage structure, high-grade steam is prioritized to complete the power generation cycle, and waste heat is stored in the molten salt system in stages. The problem of insufficient exhaust steam temperature in the back-pressure unit in the prior art is solved by the synergistic effect of steam reheater and secondary molten salt heating unit. The stored high-temperature molten salt is used to reheat the exhaust steam. In addition, the dual-unit structure of the molten salt module realizes independent storage and on-demand release of thermal energy of different qualities, avoiding grade loss caused by energy mixing. Through the cascade utilization of energy, the problem of exhaust steam temperature being lower than the actual heating temperature parameter required in the prior art is solved. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the connection structure of the system in Embodiment 1 of the present invention; Figure 2 This is a flowchart illustrating the method in Embodiment 2 of the present invention.

[0018] Figure label: 1-Boiler module, 2-First steam turbine, 3-Second steam turbine, 4-Control module, 5-First molten salt unit, 6-Second molten salt unit, 7-First molten salt pump, 8-Regulating valve I, 9-First molten salt heating unit, 10-Regulating valve II, 11-Second molten salt heating unit, 12-Second molten salt pump, 13-Regulating valve III, 14-Steam generator, 15-Regulating valve IV, 16-Steam reheater, 17-Feed water pump, 18-Regulating valve V, 19-Electric valve I, 20-Electric valve II, 21-Measurement module, 22-Electric valve III, 23-Regulating valve VI, 24-First pressure regulating valve, 25-Regulating valve VII, 26-Second pressure regulating valve, 27-Back pressure unit, 28-Regulating valve VIII, 29-Electric valve IV, 30-Deaerator.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0022] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0024] Example 1: As attached Figure 1 As shown, this embodiment provides a molten salt energy storage heating system based on coal-electricity coupling. The system is connected to a heating network to provide external heating. The system includes: Boiler module 1 is used to generate main steam, which includes a first steam component and a second steam component; A steam turbine module is connected to the boiler module 1. The steam turbine module includes a first steam turbine 2 and a second steam turbine 3. The first steam turbine 2 is used to do work using a first steam component. The first steam component after doing work returns to the boiler module 1 and generates first reheat steam. The second steam turbine 3 is used to do work using a second reheat steam. The molten salt module includes a first molten salt heating unit 9 and a second molten salt heating unit 11. The first molten salt heating unit 9 is used to exchange heat with the second steam component to generate second reheat steam. The first reheat steam and the second reheat steam form a reheat steam quantity to complete the first-stage steam heat storage. Steam reheater 16 is used to convert the amount of reheat steam; The second molten salt heating unit 11 is used to heat molten salt with second reheat steam to complete secondary steam heat storage. The second molten salt heating unit 11 is connected to the heating network to realize external heat supply. The molten salt module further includes a first molten salt unit 5 and a second molten salt unit 6. The second molten salt unit 6 is used to convert the heat of the first molten salt heating unit 9 and the second molten salt heating unit 11 to store molten salt in the first molten salt unit 5 to complete the first-stage molten salt heat storage and the second-stage molten salt heat storage. The first molten salt unit 5 is also used to release heat to the outside.

[0025] It should be noted that the problem of insufficient exhaust steam temperature in the back-pressure unit 27 in the existing technology stems from the limitation of a single energy conversion path. Through analysis, it was found that if the steam energy is stored in stages and released in phases, high-grade heat energy can be retained for power generation and low-grade heat energy can be used for heating. Further consideration is to combine the molten salt thermal storage system with the turbine module, and use the main steam diversion to achieve independent processing of different quality energy. By constructing a multi-stage thermal storage structure, high-temperature steam can be prioritized to complete the power generation cycle, and the waste heat can then enter the molten salt system for storage. During the heat release stage, parameters can be improved through steam reheating, thereby solving the problem of insufficient exhaust steam temperature.

[0026] It should be noted that boiler module 1 is preferably a device capable of heating water to generate high-temperature, high-pressure steam, specifically a pulverized coal boiler or a circulating fluidized bed boiler, with the main steam distribution controlled by adjusting combustion parameters. The turbine module is preferably a device that converts steam thermal energy into mechanical energy. The first turbine 2 can adopt a high-pressure cylinder structure, and the second turbine 3 can adopt a medium-pressure cylinder structure, achieving energy cascade utilization through staged work. The first molten salt heating unit 9 is preferably a device that uses steam to exchange heat with molten salt, specifically a shell-and-tube heat exchanger, using the heat from the second steam component to raise the molten salt temperature. The second molten salt heating unit 11 is preferably a device that performs secondary heat exchange on reheated steam, specifically a plate heat exchanger, where the steam converted by the steam reheater 16 further heats the molten salt. The first molten salt unit 5 is preferably a container for storing high-temperature molten salt, and the second molten salt unit 6 is preferably a container for storing medium / low-temperature molten salt, with the molten salt circulating between the two units via a molten salt pump. The steam reheater 16 is preferably a device for heating steam, specifically a flue gas reheater or an electric heater, used to increase the temperature parameters of the second reheat steam.

[0027] It should also be noted that the main steam generated by boiler module 1 is divided into two independent components. The first steam component enters the first steam turbine 2 to generate electricity, and after completing one energy conversion, it returns to the boiler for reheating, forming the first reheat steam. The second steam component enters the first molten salt heating unit 9, exchanges heat with the molten salt to generate the second reheat steam, and merges with the first reheat steam to form the reheat steam volume, completing the initial storage of steam energy. The reheat steam enters the second molten salt heating unit 11 after its parameters are improved by the steam reheater 16, and undergoes secondary heat exchange to heat the molten salt. At the same time, it is directly connected to the heating network to output steam that meets industrial needs. The second molten salt unit 6 integrates the heat from the two-stage heat storage process and transfers it to the first molten salt unit 5, forming molten salt storage with different temperature gradients. In the heat release stage, the high-temperature molten salt in the first molten salt unit 5 generates thermo-pressure steam through the steam generator 14, and the medium-temperature molten salt raises the exhaust temperature of the back pressure unit 27 through the steam reheater 16, realizing the staged release of energy.

[0028] Compared with existing technologies, the existing solutions use a single thermal storage path to directly generate heating steam, resulting in high-grade energy not being used for power generation. This embodiment uses a main steam diversion and multi-stage thermal storage structure to allow high-grade steam to complete the power generation cycle first, and the waste heat is stored in the molten salt system in stages. The problem of insufficient exhaust steam temperature of the back pressure unit 27 in the existing technology is solved by the synergistic effect of the steam reheater 16 and the secondary molten salt heating unit. The stored high-temperature molten salt is used to reheat the exhaust steam. In addition, the dual-unit structure of the molten salt module realizes the independent storage and on-demand release of thermal energy of different qualities, avoiding the grade loss caused by energy mixing. The problem of exhaust steam temperature being lower than the actual heating temperature parameter in the existing technology is solved by the cascade utilization of energy.

[0029] In some embodiments, the turbine module is connected to the generator set to enable power output.

[0030] In this embodiment, the system further includes: regulating valve VI 23, first pressure regulating valve 24, and electric valve IV 29, wherein the regulating valve VI 23, first pressure regulating valve 24, first molten salt heating unit 9, and electric valve IV 29 are sequentially connected to boiler module 1 to form a primary steam heat storage path, and the second steam component passes through the primary steam heat storage path and then forms reheat steam with the first steam component.

[0031] It is understood that the regulating valve VI 23 is preferably a device for regulating the flow rate of the second steam component, specifically an electric regulating valve with linear flow characteristics, controlling the steam flow rate entering the heat storage path by adjusting the opening degree; the first pressure reducing valve is preferably a device for reducing steam pressure, specifically a spring-loaded pressure reducing valve, reducing the steam pressure to adapt to the thermal conditions of the molten salt heating unit; the first molten salt heating unit 9 is preferably a device for heat exchange between steam and molten salt, specifically a shell-and-tube heat exchanger, achieving heat energy storage through countercurrent heat exchange between steam and molten salt. The electric valve IV 29 is preferably an actuator for controlling the on / off state of the heat storage path, specifically an electric shut-off valve, achieving opening and closing control of the heat storage path through switching action.

[0032] It is also understandable that when the system enters the heat storage mode, the regulating valve VI23 adjusts its opening according to the set flow value, so that the second steam component enters the heat storage path according to the preset ratio; the first pressure reducing valve reduces the steam pressure from the main steam pressure to the design working pressure of the molten salt heating unit, so as to avoid the high-pressure steam from impacting the heat exchanger; the high-temperature steam and low-temperature molten salt in the first molten salt heating unit 9 exchange heat in a countercurrent manner. After the steam releases its latent heat, it condenses into high-temperature water. After the molten salt absorbs heat, its temperature rises. The electric valve IV29 remains open during the heat storage process to ensure that the condensate after heat exchange returns smoothly to the boiler module 1; the second steam component that has completed heat exchange mixes with the first steam component discharged from the first turbine 2 to form reheat steam, maintaining the thermal cycle stability of the turbine system.

[0033] Based on the above structure, the contents of this embodiment realize precise control of the thermal storage steam path and efficient energy conversion. The steam flow regulation accuracy can be improved to within ±2% of the set value, the pressure fluctuation amplitude is reduced to less than 15% of the original value, the molten salt heat exchange efficiency is improved to more than 92% of the theoretical value, and the synergistic effect of the multi-level control device effectively avoids energy loss caused by steam parameter mismatch, providing a stable heat source guarantee for subsequent cascade energy utilization.

[0034] In this embodiment, the system further includes: regulating valve VII 25, second pressure regulating valve 26, electric valve I 19, measuring module 21, and electric valve III 22. The regulating valve VII 25, second pressure regulating valve 26, and second molten salt heating unit 11 are sequentially connected to boiler module 1 to form a secondary steam heat storage path. The secondary steam heat storage path is also sequentially connected to electric valve I 19, measuring module 21, and electric valve III 22 to form a heating path.

[0035] Based on the above structure, when the system performs secondary steam thermal storage, regulating valve VII 25 adjusts the steam flow according to the preset opening degree, and the second pressure reducing valve reduces the steam pressure to the design working pressure of the molten salt heating unit. Steam enters the second molten salt heating unit 11 to complete thermal energy storage. At this time, electric valve I 19 is in the closed state, blocking the operation of the heating path. When external heating is required, electric valve I 19 and electric valve III 22 open synchronously to form a heating channel. The measurement module 21 monitors the temperature and pressure parameters of the steam in real time, and dynamically compensates for the fluctuation of steam parameters through regulating valve VII 25 to maintain the temperature of the output steam at the set value. In this mode, the second molten salt heating unit 11 operates as both a thermal storage device and a steam parameter regulating device to ensure that the heating steam meets the industrial heat demand.

[0036] Understandably, through the above technical solution, this embodiment achieves seamless switching between the secondary steam thermal storage and heating processes. Real-time monitoring and feedback control ensure the temperature stability of the heating steam, avoiding the need for supplementary heating due to insufficient exhaust temperature of the back pressure unit 27. The data acquisition function of the measurement module 21 provides a basis for closed-loop control of steam parameters, enabling the thermal energy storage in the thermal storage stage and the thermal energy release in the heating stage to work in synergy, thereby improving the overall energy utilization efficiency of the system.

[0037] In some embodiments, the measurement module 21 is preferably a device for flow measurement.

[0038] In this embodiment, the system further includes a first molten salt pump 7 and a regulating valve I8. The first molten salt pump 7, the regulating valve I8, and the first molten salt heating unit 9 are sequentially connected to the second molten salt unit 6 to form a primary molten salt heat storage path. The primary molten salt heat storage path is connected to the first molten salt unit 5.

[0039] During the thermal storage process, the first molten salt pump 7 draws low-temperature molten salt from the second molten salt unit 6, and after the flow rate is controlled by the regulating valve I8, it is delivered to the first molten salt heating unit 9. The low-temperature molten salt exchanges heat with the second steam component in the heat exchanger, absorbing heat from the steam and transforming into high-temperature molten salt, which is then delivered to the first molten salt unit 5 to complete thermal energy storage. This path forms a closed-loop control through a pump-valve linkage mechanism. The regulating valve I8 dynamically adjusts its opening according to the molten salt temperature or system load to ensure that the residence time of the molten salt in the heat exchanger matches the heat exchange volume. The second molten salt unit 6 serves as both the starting and ending point of the molten salt cycle, providing initial molten salt supply and receiving low-temperature molten salt that has completed the heat release process, forming a complete thermal storage medium circulation system. This achieves precise control of the molten salt thermal storage path and optimization of the heat transfer process. By combining the directional flow path with the flow regulation device, the heat exchange efficiency loss caused by the disordered flow of molten salt in the traditional system is effectively solved, making the temperature gradient distribution of molten salt more uniform during the heat storage process and significantly improving the heat storage capacity of molten salt per unit time. At the same time, the separate design of the second molten salt unit 6 and the first molten salt unit 5 avoids premature mixing of hot and cold molten salts, ensuring the quality stability of stored thermal energy.

[0040] In this embodiment, the system further includes a regulating valve II 10. The first molten salt pump 7, the regulating valve II 10, and the second molten salt heating unit 11 are sequentially connected to the second molten salt unit 6 to form a secondary molten salt heat storage path. The secondary molten salt heat storage path is connected to the first molten salt unit 5.

[0041] It should be noted that during the secondary molten salt thermal storage process, the first molten salt pump 7 transports the low-temperature molten salt from the second molten salt unit 6 to the second molten salt heating unit 11, while the regulating valve II 10 controls the molten salt flow rate according to a preset opening degree. The second molten salt heating unit 11 heats the low-temperature molten salt to the target temperature by absorbing the heat energy of the second reheat steam, forming high-temperature molten salt. The high-temperature molten salt is then transported to the high-temperature zone of the first molten salt unit 5 for storage through the secondary molten salt thermal storage path. In this process, the synergistic effect of the regulating valve II 10 and the first molten salt pump 7 makes the flow rate of the secondary thermal storage path independently controllable, avoiding flow conflicts that occur when sharing a pump body with the primary thermal storage path. By using separate regulating valves, the heat from the second molten salt heating unit 11 can be directionally transported to the thermal storage unit, ensuring that the secondary thermal storage process is not interfered with by other paths.

[0042] This embodiment achieves independent operation control of the secondary molten salt thermal storage path through the above-mentioned content, and solves the problem of heat loss caused by path overlap in the multi-stage thermal storage process. By setting up separate regulating valves and dedicated pumps, the heat of the second molten salt heating unit 11 can be directionally transported to the designated thermal storage area, avoiding the mixing of molten salts of different temperatures during the transportation process, thereby improving the energy conversion efficiency and operational stability of the thermal storage system.

[0043] In this embodiment, the system further includes a second molten salt pump 12, a regulating valve III 13, and a steam generator 14. The second molten salt pump 12, the regulating valve III 13, and the steam generator 14 are sequentially connected to the first molten salt unit 5 to form a primary molten salt heat release path. The primary molten salt heat release path is connected to the second molten salt unit 6.

[0044] It should be noted that during the molten salt exothermic phase, the second molten salt pump 12 drives the high-temperature molten salt in the first molten salt unit 5 to flow along the exothermic path. The regulating valve III 13 dynamically adjusts the molten salt flow rate according to the heating demand, allowing the molten salt to enter the steam generator 14 at a set flow rate. Inside the steam generator 14, the high-temperature molten salt transfers heat to the feedwater, generating thermo-pressure steam with temperature and pressure parameters meeting the turbine's power requirements. After heat exchange, the low-temperature molten salt returns to the second molten salt unit 6, forming a closed-loop cycle. In this process, the thermal energy stored in the molten salt is no longer directly converted into heating steam, but is converted into thermo-pressure steam that can drive the turbine to generate electricity through the steam generator 14, achieving a cascade conversion of thermal energy and mechanical energy. This effectively solves the problem of wasted high-quality thermal energy during the exothermic process of the molten salt thermal storage system. By converting the molten salt thermal energy into thermo-pressure steam through the steam generator 14, the stored thermal energy can not only be used for heating but also to drive the turbine to generate electricity, achieving a dual output of thermal and electrical energy.

[0045] In this embodiment, the system further includes a regulating valve IV 15 and a steam reheater 16. The second molten salt pump 12, the regulating valve IV 15 and the steam reheater 16 are sequentially connected to the first molten salt unit 5 to form a secondary molten salt heat release path. The secondary molten salt heat release path is connected to the second molten salt unit 6.

[0046] Understandably, the second molten salt pump 12 drives the high-temperature molten salt stored in the first molten salt unit 5 to flow along the pipeline. The regulating valve IV 15 adjusts the molten salt flow rate according to the steam reheat demand. After the high-temperature molten salt enters the steam reheater 16, it exchanges heat with the steam output from the turbine module, raising the steam temperature to the set parameters. The low-temperature molten salt that has completed the heat exchange returns to the second molten salt unit 6 through the pipeline, forming a closed-loop cycle. In this process, the high-grade heat energy originally stored in the molten salt is converted into increased steam work capacity, rather than being directly used for low-grade heating.

[0047] In this embodiment, the system further includes a deaerator 30 and a back pressure machine. The deaerator 30 is connected to a feed water pump 17. The feed water pump 17 is connected to a regulating valve V18 and is connected to the steam generator 14 through the regulating valve V18. The steam generator 14 is also used to generate thermo-pressure steam and is also connected to the back pressure machine to generate back pressure steam.

[0048] The feed water pump 17 delivers deoxygenated water to the steam generator 14. The regulating valve V 18 adjusts the water volume according to the heating demand, so that the steam generator 14 converts the thermal energy stored in the molten salt into warm and pressurized steam. After the steam enters the back pressure turbine to do work and generate electricity, the temperature of the discharged back pressure steam is controlled by the inlet parameters of the steam generator 14, directly reaching the temperature required by the heating network. Through the synergistic effect of the steam generator 14 and the back pressure turbine, the high-quality thermal energy stored in the molten salt is first converted into the work capacity of the warm and pressurized steam, and then the exhaust steam still retains a sufficient temperature for heating, avoiding the energy waste caused by insufficient exhaust steam temperature of the back pressure turbine in the prior art.

[0049] In this embodiment, the system further includes electric valve II 20 and electric valve III 22. After the back pressure machine is connected to the steam reheater 16, it is also connected to electric valve II 20, measurement module 21 and electric valve III 22 in sequence to form a secondary steam heat release.

[0050] It should be noted that the low-temperature steam discharged from the back pressure compressor is introduced into the steam reheater 16, where it undergoes secondary heating using high-temperature molten salt or main steam as a heat source. Electric valves II and III operate in coordination based on steam parameters fed back from the measurement module 21. When the steam temperature is detected to be below a set threshold, the valve opening is adjusted to control the steam flow rate entering the steam reheater 16, ensuring that the temperature and pressure of the output steam meet the heating requirements. The steam reheater 16 recovers high-grade heat energy from the molten salt thermal storage system, raising the back pressure compressor exhaust temperature to the industrial heating standard range, thus forming a complete two-stage steam heat release path.

[0051] Example 2: As attached Figure 2 As shown, this embodiment provides a control method for a molten salt energy storage heating system based on coal-electricity coupling. The control method includes the following steps: Set the amount of steam for heating; The boiler module 1 controls the amount of main steam generated and controls the second steam component to enter the first molten salt heating unit 9 to heat the molten salt to the set temperature, thereby generating second reheat steam to complete the first-stage steam heat storage. The second molten salt unit 6 controls the conversion of heat between the first molten salt heating unit 9 and the second molten salt heating unit 11 to store molten salt in the first molten salt unit 5 to complete the first-stage and second-stage molten salt heat storage. The second molten salt heating unit 11 is used to heat the molten salt using the second reheat steam to complete the secondary steam thermal storage. The molten salt in the first molten salt unit 5 is controlled to return to the second molten salt unit 6 to complete the primary molten salt heat release and the secondary molten salt heat release; The steam generator 14 is controlled to produce high-temperature and high-pressure steam, and the back pressure machine is controlled to produce back pressure steam, so as to complete the first-stage steam heat release. Control the steam reheater 16 to complete the secondary steam heat release.

[0052] Understandably, the above control method achieves the gradual utilization of energy quality by establishing a multi-stage heat storage and release coordination mechanism. In the heat storage stage, the main steam is split into two streams: one for power generation and the other for heat storage. The second steam component is converted into reheated steam through molten salt heat exchange, maintaining turbine power generation efficiency while recovering waste heat. The molten salt heat storage system employs a two-stage temperature gradient storage: high-temperature molten salt is stored in the first molten salt unit 5, and low-temperature molten salt is stored in the second molten salt unit 6, forming a classified storage of thermal energy. During heat release, the molten salt flows in the opposite direction, releasing heat. The steam generator 14 converts the molten salt heat into high-temperature steam to drive the back-pressure turbine for power generation. Simultaneously, the steam reheater 16 reheats the exhaust steam from the back-pressure turbine, ensuring its temperature parameters meet industrial heating requirements. The entire process achieves closed-loop control of steam flow, molten salt temperature, and pressure through regulating valve groups and a sensor network.

[0053] Example 3: To make the technical solution of the present invention clearer, a detailed explanation is provided here in conjunction with the specific system configuration disclosed for deep-tuning thermal storage. Specifically, for the main steam thermal storage / primary thermal storage on the steam side, the amount of main steam generated by boiler module 1 is set as Q. z In some embodiments, the first steam component is set to Q. z1 The second steam component is set as Q. z2 , where Q z= Q z1+ Q z2 The first steam component enters the first steam turbine 2 to perform work. After performing work, the steam returns to the boiler module 1 to generate the first reheat steam, which is set as Q. r1 The first reheated steam continues to enter the second turbine 3 to do work, so as to ensure the safe and stable operation of the turbine module.

[0054] Secondly, the main steam volume Q generated by boiler module 1 z Extract a portion of the steam (i.e., the second steam component, denoted as Q) z2 Heat exchange with the lava module, the second steam component Q z2 The steam sequentially passes through regulating valve VI 23, first pressure regulating valve 24, first molten salt heating unit 9, and electric valve IV 29, becoming the second reheat steam in the reheat cold section, denoted as Q. r2 It returns to the original reheat cold section pipeline and connects with the first reheat steam Q. r1 The amount of reheat steam generated is denoted as Q. r , where Q r =Q r1 +Q r2 This completes the first-stage thermal storage and returns the heat to the steam reheater 16.

[0055] For reheat steam storage / secondary heat storage and external heat supply on the steam side: The amount of reheat steam heated by boiler module 1 is Q. r The first reheat steam Q r1 It enters the second steam turbine 3 to perform work; The amount of reheat steam heated by boiler module 1 is Qr, and the amount of second reheat steam is Q. r2 After exchanging heat with the molten salt module, the second reheat steam Qr2 passes through the regulating valve VII 25, the second pressure regulating valve 26, and the second molten salt heating unit 11 in sequence, and becomes steam that meets the heating parameter requirements. It is then connected to the external industrial heating network and provides external heating through the electric valve I 19, the measuring module 21, and the electric valve III 22.

[0056] For the main steam heat exchange / primary thermal storage on the molten salt side: The molten salt in the second molten salt unit 6 passes through the first molten salt pump 7, regulating valve I 8, and the first molten salt heating unit 9 in sequence, and is transformed into high-temperature molten salt and stored in the first molten salt unit 5.

[0057] For reheat steam heat exchange / secondary thermal storage on the molten salt side: The molten salt in the second molten salt unit 6 passes through the first molten salt pump 7, regulating valve II 10, and the second molten salt heating unit 11 in sequence, and is transformed into high-temperature molten salt and stored in the first molten salt unit 5.

[0058] For system configuration under exothermic conditions: Understandably, the hot molten salt in the first molten salt unit 5 is returned to the second molten salt unit 6 through the second molten salt pump 12, regulating valve III 13, and steam generator 14, thus realizing the first-stage heat release of the molten salt.

[0059] Specifically, for molten salt reheat steam exothermic / secondary exothermic: The hot molten salt in the first molten salt unit 5 is returned to the second molten salt unit 6 through the second molten salt pump 12, regulating valve IV 15, and steam reheater 16, realizing the secondary heat release of molten salt.

[0060] For the main molten salt steam / first-stage exothermic phase on the steam side: The low-pressure feedwater from deaerator 30 is pressurized by heating feedwater pump 17, and then passes through regulating valve V 18 and steam generator 14 to generate high-temperature and ultra-high-pressure steam Q. g This portion of steam, after performing work through the back pressure turbine 27, forms back pressure steam Q. g1 .

[0061] For steam reheat / secondary heat release on the steam side: Back pressure steam Q g1 After the temperature is increased by the steam reheater 16, the heat is supplied to the outside through the electric valve II 20, the measuring module 21, and the electric valve III 22 in sequence.

[0062] Example 4: To make the technical solution of the present invention clearer, a detailed explanation is provided here in conjunction with the specific operating logic of the molten salt energy storage power generation and heating system.

[0063] Understandably, the total thermal storage capacity M displayed in the control system is based on the external industrial heating steam volume Q. gy Qg y =Q g1 =Q r2 That is, the amount of steam extracted during thermal storage is equal to the amount of steam supplied during thermal storage.

[0064] The control system has entered thermal storage mode, and the heating steam quantity Q is set in the control system. gy .

[0065] Main steam thermal storage / Primary thermal storage Steam side: Open regulating valve VI23 and first pressure regulating valve 24. The control system adjusts the industrial steam extraction rate Q. gy The opening of regulating valve VI23 is controlled, and the opening of the first pressure regulating valve 24 is adjusted according to the logic setting pressure to achieve flow and pressure control. Main steam enters the first molten salt heating unit 9 to heat the low-temperature molten salt to the set temperature. The steam, after heat exchange and cooling with the molten salt, has a temperature and pressure that match the parameters of the reheat cold section, and returns to the reheat cold section system through electric valve IV29.

[0066] Molten salt side: In the control system, start the first molten salt pump 7, open the regulating valve I 8, and the control system adjusts the output based on the industrial steam extraction rate Q. gy The required flow rate of molten salt for heat exchange is calculated, and the opening of regulating valve I8 is adjusted to control the flow rate of molten salt. The hot molten salt after heat exchange with steam is stored in the first molten salt unit 5.

[0067] Reheat steam thermal storage / secondary thermal storage: Steam side: Open regulating valve VII 25 and second pressure regulating valve 26. The control system controls the opening of regulating valve VII 25 according to the industrial steam extraction volume Qgy, and adjusts the opening of second pressure regulating valve 26 according to the logic setting pressure to achieve flow and pressure control. Reheated steam enters the second molten salt heating unit 11 to heat the low-temperature molten salt to the set temperature. The temperature and pressure of the steam after heat exchange with the molten salt match the industrial heating parameters. Open electric valve I 19 and electric valve III 22 to achieve external heating. The measurement module 21 sends the flow signal to the control system and further corrects the opening of the flow control valve.

[0068] Molten salt side: First molten salt pump 7 has started, regulating valve II 10 is open, and the control system adjusts according to the industrial steam extraction rate Q. gy The required molten salt flow rate for heat exchange is calculated, and the opening of regulating valve II10 is adjusted to control the molten salt flow rate. The hot molten salt after heat exchange with steam is stored in the first molten salt unit 5.

[0069] When the molten salt thermal storage is completed and the first molten salt unit 5 is full, energy storage ends, the thermal storage and heating operation stops, the turbine load is increased, and the operation is adjusted to normal heating mode. Control valve VI 23, first pressure regulating valve 24, control valve VII 25, second pressure regulating valve 26, electric valve I 19, and electric valve IV 29 are closed, and the steam pipeline is in hot standby mode. The first molten salt pump 7 is shut down, and control valve I 8 and control valve II 10 are closed, and the cold molten salt pipeline is in hot standby mode.

[0070] Exothermic peak operating logic: Main molten salt steam / primary exothermic reaction: Molten salt side: Start the second molten salt pump 12 in the control system, open the regulating valve Ⅲ 13, and the control system adjusts the industrial steam extraction rate Q. gyThe required flow rate of molten salt for heat exchange is calculated, and the opening of regulating valve Ⅲ13 is adjusted to control the flow rate of molten salt. The low-temperature molten salt after heat exchange between molten salt and feedwater in steam generator 14 is stored in the second molten salt unit 6.

[0071] Steam side: In the control system, start the heating feedwater pump 17 and open regulating valves V18 and VIII28. The control system adjusts the industrial steam extraction rate Q. gy The opening of regulating valve V18 controls the water flow rate. After passing through steam generator 14, it generates high-temperature and ultra-high-pressure steam. After the pressure is adjusted by regulating valve VIII28, it enters back pressure unit 27 to perform full work and generate electricity for external sale.

[0072] Steam reheat / secondary exothermic reaction: Steam side: The steam temperature after the back pressure unit 27 has done its work is insufficient to meet the heating temperature requirements. The back pressure steam is heated to the industrial heating parameters through the steam reheater 16, and the electric valves II 20 and III 22 are opened to achieve external heating. The measurement module 21 sends the flow signal to the control system and further corrects the flow to control the opening of the regulating valve V 18.

[0073] Molten salt side: The second molten salt pump 12 has been started, and regulating valve IV 15 has been opened. The control system calculates the required molten salt flow rate for heat exchange based on the back pressure turbine exhaust parameters and adjusts the opening of regulating valve IV 15 to control the molten salt flow rate. The low-temperature molten salt after heat exchange between the molten salt and back pressure steam in the steam reheater 16 is stored in the second molten salt unit 6.

[0074] When the molten salt heat release ends and the molten salt in the first molten salt unit 5 has been completely released, the energy release ends, the heat release operation stops, the turbine load is reduced, and the operation is adjusted to normal heating mode. Regulating valve V18, regulating valve VIII28, electric valve II20, and electric valve III22 are closed, and the steam pipeline is in hot standby mode; the second molten salt pump 12 is shut down, and regulating valve III13 and regulating valve IV15 are closed, and the hot molten salt pipeline is in hot standby mode.

[0075] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A molten salt energy storage and heating system based on coal-electricity coupling, characterized in that, The system is connected to the heating network to provide external heating, and the system includes: A boiler module for generating main steam, the main steam including a first steam component and a second steam component; A steam turbine module is connected to the boiler module. The steam turbine module includes a first steam turbine and a second steam turbine. The first steam turbine is used to do work using a first steam component. The first steam component after doing work returns to the boiler module and generates first reheat steam. The second steam turbine is used to do work using a second reheat steam. The molten salt module includes a first molten salt heating unit and a second molten salt heating unit. The first molten salt heating unit is used to exchange heat with a second steam component to generate a second reheated steam. The first reheated steam and the second reheated steam form a reheated steam quantity to complete the first-stage steam heat storage. Steam reheater is used to convert the amount of reheat steam. The second molten salt heating unit is used to heat molten salt with the second reheat steam to complete the secondary steam heat storage. The second molten salt heating unit is connected to the heating network to provide external heat. The molten salt module further includes a first molten salt unit and a second molten salt unit. The second molten salt unit is used to convert the heat of the first molten salt heating unit and the second molten salt heating unit to store molten salt in the first molten salt unit to complete the first-stage molten salt heat storage and the second-stage molten salt heat storage. The first molten salt unit is also used to release heat to the outside.

2. The molten salt energy storage and heating system based on coal-electricity coupling as described in claim 1, characterized in that, The system further includes: regulating valve VI, first pressure regulating valve, and electric valve IV, wherein the regulating valve VI, first pressure regulating valve, first molten salt heating unit, and electric valve IV are sequentially connected to the boiler module to form a primary steam heat storage path, and the second steam component passes through the primary steam heat storage path and then combines with the first steam component to form reheat steam.

3. The molten salt energy storage and heating system based on coal-electricity coupling as described in claim 1, characterized in that, The system also includes: regulating valve VII, second pressure regulating valve, electric valve I, measuring module and electric valve III, wherein the regulating valve VII, the second pressure regulating valve and the second molten salt heating unit are sequentially connected to the boiler module to form a secondary steam heat storage path, and the secondary steam heat storage path is also sequentially connected to electric valve I, measuring module and electric valve III to form a heating path.

4. The molten salt energy storage and heating system based on coal-electricity coupling as described in claim 1, characterized in that, The system also includes a first molten salt pump and a regulating valve I. The first molten salt pump, the regulating valve I, and the first molten salt heating unit are sequentially connected to the second molten salt unit to form a primary molten salt heat storage path. The primary molten salt heat storage path is connected to the first molten salt unit.

5. A molten salt energy storage and heating system based on coal-electricity coupling as described in claim 4, characterized in that, The system also includes a regulating valve II. The first molten salt pump, the regulating valve II, and the second molten salt heating unit are sequentially connected to the second molten salt unit to form a secondary molten salt heat storage path. The secondary molten salt heat storage path is connected to the first molten salt unit.

6. The molten salt energy storage and heating system based on coal-electricity coupling as described in claim 1, characterized in that, The system also includes a second molten salt pump, a regulating valve III, and a steam generator. The second molten salt pump, the regulating valve III, and the steam generator are sequentially connected to the first molten salt unit to form a primary molten salt heat release path, and the primary molten salt heat release path is connected to the second molten salt unit.

7. A molten salt energy storage and heating system based on coal-electricity coupling as described in claim 6, characterized in that, The system also includes a regulating valve IV and a steam reheater. The second molten salt pump, the regulating valve IV, and the steam reheater are sequentially connected to the first molten salt unit to form a secondary molten salt heat release path. The secondary molten salt heat release path is connected to the second molten salt unit.

8. A molten salt energy storage and heating system based on coal-electricity coupling as described in claim 7, characterized in that, The system also includes a deaerator and a back pressure unit. The deaerator is connected to a feedwater pump. The feedwater pump is connected to a regulating valve V and is connected to the steam generator through the regulating valve V. The steam generator is also used to generate thermo-pressure steam and is also connected to the back pressure unit to generate back pressure steam.

9. A molten salt energy storage and heating system based on coal-electricity coupling as described in claim 8, characterized in that, The system also includes electric valve II and electric valve III. After the back pressure machine is connected to the steam reheater, it is also connected to electric valve II, the measurement module and electric valve III in sequence to form a two-stage steam heat release.

10. A control method for a molten salt energy storage heating system based on coal-electricity coupling, characterized in that, The control method is based on the molten salt energy storage heating system based on coal-electricity coupling as described in claim 9, and the control method includes the following steps: Set the amount of steam for heating; The boiler module generates the main steam, and the second steam component is controlled to enter the first molten salt heating unit to heat the molten salt to the set temperature, generating the second reheat steam to complete the first-stage steam heat storage. The second molten salt unit controls the conversion of heat between the first molten salt heating unit and the second molten salt heating unit to store molten salt in the first molten salt unit, thus completing the first-stage and second-stage molten salt heat storage. The second molten salt heating unit is controlled to heat the molten salt using the second reheat steam to complete the secondary steam thermal storage. The molten salt from the first molten salt unit is controlled to return to the second molten salt unit to complete the primary and secondary molten salt heat release. The steam generator is controlled to produce high-temperature and high-pressure steam, and the back pressure machine is controlled to produce back-pressure steam, so as to complete the first-stage steam heat release. Control the steam reheater to complete the secondary steam heat release.

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