A coupled multi-tank molten salt thermal storage thermal system and method

Abstract

The application belongs to the technical field of thermal energy storage and power generation technology, and specifically discloses a coupled multi-tank molten salt heat storage thermal system and method. The outlet of the low-temperature molten salt tank is divided into two routes: the first route is connected to the salt side inlet of the four-extraction molten salt heat exchanger through the four-extraction molten salt heat exchanger salt inlet valve, and the second route is connected to the salt side inlet of the second hot remolten salt heat exchanger through the second hot remolten salt heat exchanger salt inlet valve. The salt side outlet of the four-extraction molten salt heat exchanger is divided into two routes: one route is connected to the salt side inlet of the first hot remolten salt heat exchanger through the second inlet valve, and the other route is connected to the medium-temperature molten salt tank through the first inlet valve. The salt side outlet of the second hot remolten salt heat exchanger is divided into two routes: one route is connected to the medium-temperature molten salt tank, and the other route is connected to the salt side inlet of the first hot remolten salt heat exchanger through the first hot remolten salt heat exchanger salt inlet valve. The steam side outlet of the molten salt steam generator is divided into two routes and connected to the steam inlet of the high-pressure steam supply header and the medium-pressure cylinder respectively. The application can improve the energy utilization rate of the system.

Description

Technical Field

[0001] This invention relates to the field of thermal energy storage and power generation technology, specifically to a coupled multi-tank molten salt thermal energy storage system and method. Background Technology

[0002] For industrial steam turbine units, there are generally low-pressure and high-pressure gas supply requirements. For units with multi-source steam extraction, the existing multi-stage steam extraction coupled molten salt thermal storage system generally uses ternary molten salt as the thermal storage medium. The theoretical decomposition temperature of ternary molten salt is 450℃, and the upper limit of the actual operating control temperature is 390℃. However, for multi-source steam extraction in steam turbine units, the hot re-extraction temperature is generally 500-550℃. Usually, water spraying is required for desuperheating before heat exchange with molten salt, which results in energy loss and reduced thermal economy. Summary of the Invention

[0003] This invention provides a coupled multi-tank molten salt thermal storage system and method, with the aim of improving the system's energy utilization rate.

[0004] This invention is achieved through the following technical solution: a coupled multi-tank molten salt thermal storage system, comprising:

[0005] Low-temperature molten salt tank, medium-temperature molten salt tank, high-temperature molten salt tank, four-extraction molten salt heat exchanger, first-heat remelted molten salt heat exchanger, second-heat remelted molten salt heat exchanger, molten salt steam generator, intermediate-pressure cylinder, high-pressure steam supply manifold and low-pressure steam supply manifold;

[0006] in,

[0007] The outlet of the low-temperature molten salt tank is divided into two paths: the first path is connected to the salt side inlet of the four-extraction molten salt heat exchanger through the salt inlet valve of the four-extraction molten salt heat exchanger, and the second path is connected to the salt side inlet of the second hot remelt salt heat exchanger through the salt inlet valve of the second hot remelt salt heat exchanger.

[0008] The salt-side outlet of the four-extraction molten salt heat exchanger is divided into two paths: one path is connected to the salt-side inlet of the first reheat molten salt heat exchanger through the second inlet valve, and the other path is connected to the medium-temperature molten salt tank through the first inlet valve.

[0009] The salt-side outlet of the second hot remelt salt heat exchanger is divided into two paths: one path is connected to the medium-temperature molten salt tank, and the other path is connected to the salt-side inlet of the first hot remelt salt heat exchanger through the salt inlet valve of the first hot remelt salt heat exchanger.

[0010] The salt-side outlet of the first hot remelted salt heat exchanger is connected to a high-temperature molten salt tank.

[0011] The medium-temperature molten salt tank and the high-temperature molten salt tank are respectively connected to the salt-side inlet of the molten salt steam generator;

[0012] The steam outlet of the molten salt steam generator is divided into two paths, which are respectively connected to the steam inlet of the high-pressure steam supply manifold and the intermediate-pressure cylinder.

[0013] Furthermore, a low-temperature molten salt pump is installed at the outlet of the low-temperature molten salt tank, and a medium-temperature molten salt pump is installed at the outlet of the medium-temperature molten salt tank. The medium-temperature molten salt pump is connected to the salt-side inlet of the molten salt steam generator through a medium-temperature salt inlet valve.

[0014] The outlet of the high-temperature molten salt tank is equipped with a high-temperature molten salt pump, which is connected to the salt-side inlet of the molten salt steam generator through a high-temperature salt inlet valve.

[0015] Furthermore, a third steam inlet valve is installed on the pipeline between the steam-side outlet of the molten salt steam generator and the high-pressure steam supply manifold, and a fourth steam inlet valve is installed on the pipeline between the steam-side outlet of the molten salt steam generator and the steam inlet of the intermediate-pressure cylinder.

[0016] Furthermore, the steam inlet pipe of the intermediate pressure cylinder is connected to the steam side inlet of the first hot remelt salt heat exchanger through the fifth steam inlet valve, and the steam side outlet of the first hot remelt salt heat exchanger is connected to the steam side inlet of the second hot remelt salt heat exchanger.

[0017] The steam outlet of the second reheat molten salt heat exchanger is divided into two paths, which are connected to the high-pressure steam supply manifold and the low-pressure steam supply manifold respectively through the first steam inlet valve and the second steam inlet valve.

[0018] Furthermore, the intermediate-pressure cylinder is connected to the steam inlet of the four-extraction molten salt heat exchanger via the sixth steam inlet valve, and the steam outlet of the four-extraction molten salt heat exchanger is connected to the steam inlet of the low-pressure steam supply manifold.

[0019] A coupled multi-tank molten salt thermal storage method, using the aforementioned coupled multi-tank molten salt thermal storage system, includes the following steps:

[0020] Under normal generating load conditions of the unit:

[0021] Molten salt enters the four-extraction molten salt heat exchanger sequentially from one of the channels in the low-temperature molten salt tank, then enters the first hot remelt molten salt heat exchanger through one of the channels in the four-extraction molten salt heat exchanger, and then enters the high-temperature molten salt tank for storage from the salt side outlet of the first hot remelt molten salt heat exchanger; molten salt enters the medium-temperature molten salt tank through the other channel in the four-extraction molten salt heat exchanger; molten salt enters the second hot remelt molten salt heat exchanger from the other channel in the low-temperature molten salt tank, and finally enters the medium-temperature molten salt tank;

[0022] The high-temperature hot re-extraction steam sequentially enters the first hot re-molten salt heat exchanger and the second hot re-molten salt heat exchanger, where it undergoes cascade heat exchange with the molten salt, and finally enters the high-pressure steam supply header.

[0023] Under deep peak load conditions of the unit:

[0024] After the molten salt enters the second hot remelted salt heat exchanger sequentially from the low-temperature molten salt tank, it enters the first hot remelted salt heat exchanger through one of the two paths of the second hot remelted salt heat exchanger, and enters the medium-temperature molten salt tank through the other path. The steam generated by the medium-temperature molten salt tank is used to supply the high-pressure steam supply manifold.

[0025] The high-temperature hot re-extraction steam sequentially enters the first hot re-molten salt heat exchanger and the second hot re-molten salt heat exchanger, where it undergoes cascade heat exchange with the molten salt and finally enters the low-pressure steam supply manifold.

[0026] Under peak load conditions of unit power generation:

[0027] Molten salt enters the four-extraction molten salt heat exchanger sequentially from one of the paths in the low-temperature molten salt tank, then enters the first hot remelt molten salt heat exchanger through one of the paths in the four-extraction molten salt heat exchanger, then enters the high-temperature molten salt tank from the salt side outlet of the first hot remelt molten salt heat exchanger, and then enters the molten salt steam generator from the high-temperature molten salt tank, and finally enters the medium-pressure cylinder; molten salt enters the medium-temperature molten salt tank through the other path in the four-extraction molten salt heat exchanger; molten salt enters the second hot remelt molten salt heat exchanger from the other path in the low-temperature molten salt tank, and finally enters the medium-temperature molten salt tank;

[0028] The high-temperature hot re-extraction steam sequentially enters the first hot re-molten salt heat exchanger and the second hot re-molten salt heat exchanger, where it undergoes cascade heat exchange with the molten salt, and finally enters the high-pressure steam supply header.

[0029] Furthermore, determining the molten salt pump speed, valve opening, and molten salt diversion ratio in a coupled multi-tank molten salt thermal storage system as described above specifically includes the following steps:

[0030] S1. Determine and obtain the key factors affecting the thermodynamic performance of the system. The key factors include:

[0031] State variables: Unit load Hot re-extraction steam temperature Four-stage temperature Low-temperature molten salt tank outlet temperature Temperature of medium-temperature molten salt tank Temperature of high-temperature molten salt tank Flow rate of each pipeline High-pressure steam supply pressure Low-pressure steam supply pressure ;

[0032] Decision variable: Cryogenic molten salt pump speed Medium-temperature molten salt pump speed High-temperature molten salt pump speed , opening degree of each valve And the distribution of molten salt between the heat exchangers ,in Indicates a branch node;

[0033] S2. Based on the aforementioned state variables and decision variables, establish a calculation model for the thermal performance indicators of the molten salt thermal storage system, wherein the thermal performance indicators include energy utilization rate. Heat loss Steam supply stability molten salt pump energy consumption ;

[0034] S3. Establish an optimized operation model with the aforementioned thermal performance indicators as the objective, encode the decision variables, and solve for the optimal combination of the decision variables based on a genetic algorithm;

[0035] S4. Based on the optimal combination of decision variables obtained from the solution, adjust the speed of the molten salt pump, the valve opening, and the molten salt diversion ratio to control the system.

[0036] Furthermore, the calculation model for the thermodynamic performance indicators mentioned in S2 includes:

[0037] Energy utilization rate The expression is:

[0038] ;

[0039] in, This is the sum of the system's output heat energy and electrical energy. The thermal energy input to the system is determined based on the unit load in the state variables. Hot re-extraction steam temperature Four-stage temperature Flow rate of each pipeline Calculated;

[0040] Heat loss The expression is:

[0041] ;

[0042] in, For the first The flow rate of this pipeline The specific heat capacity of molten salt or steam. For the first The temperature difference loss of the pipeline is determined based on the temperature at each point in the state variables. Calculated;

[0043] Steam supply stability The expression is:

[0044] ;

[0045] in, This is the high-pressure steam supply pressure. For low-pressure steam supply, and For the target steam supply pressure, To prevent the division of zero by a small constant;

[0046] Molten salt pump energy consumption The calculation formula is:

[0047] ;

[0048] in, The density of molten salt, It is the acceleration due to gravity. For the first The head of the molten salt pump For the first The flow rate of the molten salt pump For the first The efficiency of the molten salt pump, among which Based on the pump speed in the decision variable and valve opening Calculated.

[0049] Furthermore, the specific steps of S3 are as follows:

[0050] S3.1 Set the number of iterations G, population size N, and crossover probability for the genetic algorithm. Probability of mutation ;

[0051] S3.2 Establish an optimized operation model for the molten salt thermal storage system. The optimized operation model includes an objective function and constraints, wherein the objective function is:

[0052] ;

[0053] in, The decision variable vector includes the molten salt pump speed. Valve opening Molten salt split ratio ; These are weighting coefficients, which are dynamically adjusted based on operating conditions.

[0054] The constraints include:

[0055] Temperature constraints: To prevent the molten salt from decomposing or solidifying;

[0056] Pressure constraints: To ensure the quality of steam supply;

[0057] Flow constraints: To prevent pipeline overload;

[0058] Valve opening constraint: 0 ≤ ≤ 100%;

[0059] Pump speed constraint: ≤ ≤ ;

[0060] S3.3 Encode the decision variables with real numbers. Each individual represents a combination of decision variables. Based on the constraints, randomly generate N individuals to form an initial population. Let this initial population be the parent population.

[0061] S3.4. Substitute the decision variable values ​​of each individual in the parent population along with the real-time collected state variable values ​​into the thermal performance index calculation model described in S2 to calculate the energy utilization rate of each individual. Heat loss Steam supply stability molten salt pump energy consumption ;

[0062] S3.5. Calculate the objective function value for each individual in the parent population based on the calculation results of S3.4. Then, the fitness value of each individual in the parent population is calculated and sorted according to the fitness function;

[0063] S3.6. Save the top M parent individuals with the largest fitness values ​​in the parent population. Select parent individuals from all parent individuals other than the top M parent individuals with the largest fitness values ​​through a roulette wheel and perform crossover and mutation operations to obtain offspring individuals. Calculate the fitness values ​​of the offspring individuals after crossover and mutation and sort them. Reinsert the offspring individuals into the parent population according to their fitness values. Select a set number of individuals to be solved to form a new parent population, and then return to S3.4.

[0064] S3.7 Repeat S3.4 to S3.6 until the number of iterations G is reached or the change in the objective function value is less than the set threshold. The resulting parent population is the optimal set of operating parameters, and the parent individuals in the parent population are the optimal combination of decision variables.

[0065] Furthermore, the fitness function is:

[0066] ;

[0067] in, For the theoretically optimal target value or the preset target value, This represents the objective function value for the current individual.

[0068] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0069] This invention designs a coupled multi-tank molten salt thermal storage system and method. The system innovatively designs a multi-tank molten salt thermal storage system using a binary salt as the working fluid. Based on the principles of temperature matching and tiered utilization, the system divides the process of heating molten salt with hot reheat steam into two stages. In the first heat exchange stage, the medium-temperature molten salt heated in the second heating stage is used to cool the high-temperature hot reheat steam (500-550℃), replacing the conventional water spray cooling method. The high-temperature molten salt heated in the first heat exchange stage is stored in a high-temperature molten salt tank. In the second heat exchange stage, the hot reheat steam (around 400℃) cooled in the first heat exchange stage exchanges heat with the low-temperature molten salt. The portion of the medium-temperature molten salt heated in the second heat exchange stage enters the medium-temperature molten salt tank.

[0070] In addition, during peak power generation, molten salt from the high-temperature molten salt tank is used to enter the steam generator for heat release, generating steam to supplement the intermediate-pressure cylinder and improve the unit's peak capacity.

[0071] During off-peak power generation, molten salt from the medium-temperature molten salt tank is used to enter the steam generator for heat release, generating steam which is then sent to the high-pressure gas supply header to compensate for the unit's low-load gas supply capacity.

[0072] Based on the above measures, the energy utilization rate of the molten salt energy storage system can be effectively improved, and the thermal economy of the system can be enhanced.

[0073] Furthermore, the present invention achieves adaptive optimization of the system through a genetic algorithm intelligent control module. The genetic algorithm optimizes the molten salt pump speed, valve opening, and flow ratio in real time, ensuring that the system always operates under optimal conditions. In addition, the present invention optimizes the flow ratio of molten salt between tanks through the genetic algorithm, reducing the ineffective circulation of molten salt in pipes and heat exchangers, and significantly reducing heat loss.

[0074] This invention uses a genetic algorithm to precisely adjust the speed of the molten salt pump and the valve opening, replacing the traditional on / off control mode of fixed-speed pumps and on / off valves. It can dynamically match the output power of the molten salt pump according to the real-time flow demand, avoiding the energy waste of the pump body caused by large flow and small load. At the same time, by optimizing the molten salt diversion ratio and heat exchange path, it reduces the temperature difference loss between the pipeline and the heat exchanger, and combines the thermodynamic performance index calculation model to accurately control the heat loss.

[0075] Furthermore, this invention uses a genetic algorithm to collect key state variables such as unit load, extraction steam temperature, molten salt temperature, and steam supply pressure / flow rate in real time, constructs a quantitative model of steam supply stability, and incorporates it into the optimization objective. By dynamically adjusting decision variables, the high-pressure and low-pressure steam supply pressures are kept close to the target values, effectively avoiding the problem of sudden rises and falls in steam supply pressure caused by dynamic fluctuations in parameters under traditional fixed control strategies. At the same time, the optimized molten salt flow rate and heat exchange ratio can prevent molten salt overheating decomposition, low-temperature solidification, and pipeline overload, avoiding operational failures of molten salt-side equipment from the source. The continuous fault-free operation time of the system is effectively improved, ensuring the continuous and stable operation of unit power generation and industrial steam supply.

[0076] This invention deeply couples genetic algorithms with molten salt thermal storage systems. By encoding multi-dimensional decision variables such as molten salt pump speed, valve opening, and molten salt diversion ratio with real numbers and performing multi-generation iterative optimization, it can solve for the globally optimal combination of operating parameters under multiple constraints such as temperature, pressure, flow rate, and opening degree, replacing traditional manual preset parameters and experience-based control. At the same time, the algorithm has the characteristics of fast iterative convergence and high solution accuracy. The solution time of a single iteration can meet the real-time control requirements of industrial thermal systems, upgrading the molten salt thermal storage system from mechanical on / off control to multi-objective intelligent optimization control, and significantly improving the intelligent control level of the unit's thermal system. Attached Figure Description

[0077] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0078] Figure 1 This is a schematic diagram of an embodiment of a coupled multi-tank molten salt thermal storage system according to the present invention;

[0079] Figure 2 This is a schematic diagram of the pipeline connection structure under normal power generation load of a unit in an embodiment of a coupled multi-tank molten salt thermal energy storage system of the present invention;

[0080] Figure 3 This is a schematic diagram of the pipeline connection structure during deep peak load regulation of a unit in an embodiment of a coupled multi-tank molten salt thermal energy storage system of the present invention;

[0081] Figure 4 This is a schematic diagram of the pipeline connection structure during peak load generation of a unit in an embodiment of a coupled multi-tank molten salt thermal storage system of the present invention.

[0082] The attached diagram shows the markings and corresponding component names:

[0083] 1. Low-temperature molten salt tank; 2. Medium-temperature molten salt tank; 3. High-temperature molten salt tank; 4. Low-temperature molten salt pump; 5. Medium-temperature molten salt pump; 6. High-temperature molten salt pump; 7. Four-extraction molten salt heat exchanger inlet valve; 8. Second hot remelted molten salt heat exchanger inlet valve; 9. Medium-temperature inlet valve; 10. High-temperature inlet valve; 11. Four-extraction molten salt heat exchanger; 12. First hot remelted molten salt heat exchanger; 13. Second hot remelted molten salt heat exchanger; 14. First inlet valve; 15. Second inlet valve; 16. Molten salt steam generator; 17. First steam inlet valve; 18. Second steam inlet valve; 19. Third steam inlet valve; 20. Fourth steam inlet valve; 21. Desuperheating water valve; 22. Desuperheater; 23. Fifth steam inlet valve; 24. Intermediate pressure cylinder; 25. Sixth steam inlet valve; 26. First hot remelted molten salt heat exchanger inlet valve. Detailed Implementation

[0084] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0085] As one embodiment of this application, such as Figure 1 As shown, this embodiment provides a coupled multi-tank molten salt thermal storage system, including:

[0086] Low-temperature molten salt tank 1, medium-temperature molten salt tank 2, high-temperature molten salt tank 3, four-extraction molten salt heat exchanger 11, first reheat molten salt heat exchanger 12, second reheat molten salt heat exchanger 13, molten salt steam generator 16, medium-pressure cylinder 24, high-pressure steam supply manifold and low-pressure steam supply manifold.

[0087] in,

[0088] The outlet of the low-temperature molten salt tank 1 is divided into two paths: the first path is connected to the salt side inlet of the four-extraction molten salt heat exchanger 11 through the salt inlet valve 7 of the four-extraction molten salt heat exchanger, and the second path is connected to the salt side inlet of the second-heat remelted salt heat exchanger 13 through the salt inlet valve 8 of the second-heat remelted salt heat exchanger.

[0089] The salt-side outlet of the four-extraction molten salt heat exchanger 11 is divided into two paths: one path is connected to the salt-side inlet of the first reheat molten salt heat exchanger 12 through the second inlet valve 15, and the other path is connected to the medium-temperature molten salt tank 2 through the first inlet valve 14.

[0090] The salt-side outlet of the second remelted salt heat exchanger 13 is divided into two paths: one path is connected to the medium-temperature molten salt tank 2, and the other path is connected to the salt-side inlet of the first remelted salt heat exchanger 12 through the salt inlet valve 26 of the first remelted salt heat exchanger.

[0091] The salt-side outlet of the first remelted salt heat exchanger 12 is connected to the high-temperature molten salt tank 3;

[0092] The outlets of the medium-temperature molten salt tank 2 and the high-temperature molten salt tank 3 are respectively connected to the salt-side inlet of the molten salt steam generator 16;

[0093] The steam outlet of the molten salt steam generator 16 is divided into two paths, which are connected to the high-pressure steam supply manifold and the steam inlet of the intermediate-pressure cylinder 24, respectively.

[0094] In this embodiment, the outlet of the low-temperature molten salt tank 1 is equipped with a low-temperature molten salt pump 4, and the outlet of the medium-temperature molten salt tank 2 is equipped with a medium-temperature molten salt pump 5. The medium-temperature molten salt pump 5 is connected to the salt side inlet of the molten salt steam generator through a medium-temperature salt inlet valve 9.

[0095] The outlet of the high-temperature molten salt tank 3 is equipped with a high-temperature molten salt pump 6, which is connected to the salt side inlet of the molten salt steam generator through a high-temperature salt inlet valve 10.

[0096] In one embodiment, such as Figure 1 As shown, in this embodiment, a third steam inlet valve 19 is installed on the pipeline between the steam side outlet of the molten salt steam generator 16 and the high-pressure steam supply manifold, and a fourth steam inlet valve 20 is installed on the pipeline between the steam side outlet of the molten salt steam generator 16 and the steam inlet of the intermediate-pressure cylinder 24.

[0097] In one embodiment, such as Figure 1 As shown, in this embodiment, a desuperheater 22 is also installed on the pipeline between the steam side outlet of the molten salt steam generator 16 and the high-pressure steam supply header. The desuperheater 22 is located between the high-pressure steam supply header and the third steam inlet valve 19. In this embodiment, the desuperheater 22 is connected to a desuperheating pipeline, and a desuperheating water valve 21 is installed on the desuperheating pipeline.

[0098] In this embodiment, the desuperheater 22 can precisely control the injection amount of desuperheating water by adjusting the opening of the desuperheating water valve 21, and spray water to desuperheat / adjust the temperature of the steam output from the molten salt steam generator, so as to stably control the steam temperature within the rated temperature range of the high-pressure steam supply header, achieve precise matching between the steam temperature and the high-pressure industrial steam supply demand, and ensure the normal and efficient operation of the industrial steam-using equipment.

[0099] In one embodiment, such as Figure 1 As shown, in this embodiment, the steam inlet pipe of the intermediate pressure cylinder 24 is connected to the steam side inlet of the first hot remelt salt heat exchanger 12 through the fifth steam inlet valve 23. That is, the steam inlet pipe of the intermediate pressure cylinder 24 is connected to the first hot remelt salt heat exchanger 12 through a branch road, and the fifth steam inlet valve 23 is installed on the branch road and connected to the first hot remelt salt heat exchanger 12. The steam side outlet of the first hot remelt salt heat exchanger 12 is connected to the steam side inlet of the second hot remelt salt heat exchanger 13.

[0100] The steam outlet of the second remelted salt heat exchanger 13 is divided into two paths, which are connected to the high-pressure steam supply manifold and the low-pressure steam supply manifold respectively through the first steam inlet valve 17 and the second steam inlet valve 18.

[0101] In one embodiment, such as Figure 1As shown, in this embodiment, the outlet of the intermediate pressure cylinder 24 is connected to the steam inlet of the four-extraction molten salt heat exchanger 11 through the sixth steam inlet valve 25, and the steam outlet of the four-extraction molten salt heat exchanger 11 is connected to the steam inlet of the low-pressure steam supply manifold.

[0102] In another embodiment, this embodiment discloses a coupled multi-tank molten salt thermal storage method, using the above-described coupled multi-tank molten salt thermal storage system, including the following steps:

[0103] like Figure 2 As shown, under normal generating load conditions (the red pipeline section indicates the flow status of each pipeline under this condition):

[0104] For the molten salt absorber side: Start the cryogenic molten salt pump 4, open the inlet valve 7, the first inlet valve 14, and the second inlet valve 15 of the four-stage molten salt heat exchanger; open the inlet valve 8 of the second reheat molten salt heat exchanger and close the inlet valve 26 of the first reheat molten salt heat exchanger; open the sixth steam inlet valve 25, the fifth steam inlet valve 23, the first steam inlet valve 17, and close the second steam inlet valve 18.

[0105] Molten salt enters the four-extraction molten salt heat exchanger 11 sequentially from one of the channels in the low-temperature molten salt tank 1 through the salt inlet valve 7 of the four-extraction molten salt heat exchanger 11. Then, it enters the first hot remelt molten salt heat exchanger 12 through the salt side outlet of the four-extraction molten salt heat exchanger 11 via the second inlet valve 15. Finally, it enters the high-temperature molten salt tank 3 for storage from the salt side outlet of the first hot remelt molten salt heat exchanger 12. Molten salt enters the medium-temperature molten salt tank 2 through the first inlet valve 14 via another channel from the salt side outlet of the four-extraction molten salt heat exchanger 11. Molten salt enters the second hot remelt molten salt heat exchanger 13 through the salt side inlet of the second hot remelt molten salt heat exchanger 13 via another channel from the low-temperature molten salt tank 11. Finally, it enters the medium-temperature molten salt tank 2 from the salt side outlet of the second hot remelt molten salt heat exchanger 13.

[0106] The high-temperature hot re-extraction steam sequentially enters the first hot re-extraction molten salt heat exchanger 12 and the second hot re-extraction molten salt heat exchanger 13, where it undergoes cascade heat exchange with the molten salt, and finally enters the high-pressure steam supply header. Specifically: the high-temperature hot re-extraction steam enters the first hot re-extraction molten salt heat exchanger 12 from a branch of the steam inlet pipe of the intermediate-pressure cylinder 24 via the fifth steam inlet valve 23, and then enters the second hot re-extraction molten salt heat exchanger 13 from the steam inlet of the first hot re-extraction molten salt heat exchanger 12 via the steam inlet of the second hot re-extraction molten salt heat exchanger 13 via the steam inlet of the first hot re-extraction molten salt heat exchanger 12 via the steam inlet of the second hot re-extraction molten salt heat exchanger 13 via the steam inlet of the second hot re-extraction molten salt heat exchanger 13 via the steam inlet of the second hot re-extraction molten salt heat exchanger 13; the high-temperature hot re-extraction steam enters the intermediate-pressure cylinder 24 from another branch of the steam inlet pipe of the intermediate-pressure cylinder 24, and then enters the fourth-extraction molten salt heat exchanger 11 from the steam inlet of the fourth-extraction molten salt heat exchanger 11 via the sixth steam inlet valve 25 from the outlet of the intermediate-pressure cylinder 24.

[0107] like Figure 3As shown, this is the unit under deep peak load operation (the blue pipeline section indicates the flow status of each pipeline under this operation):

[0108] For the molten salt absorber side: close the inlet valve 7, the first inlet valve 14, and the second inlet valve 15 of the four-extraction molten salt heat exchanger; open the inlet valve 8 of the second reheat molten salt heat exchanger and the inlet valve 26 of the first reheat molten salt heat exchanger; close the sixth steam inlet valve 25, open the fifth steam inlet valve 23, close the first steam inlet valve 17, open the second steam inlet valve 18, and start the cryogenic molten salt pump 4;

[0109] Molten salt enters the second remelted salt heat exchanger 13 from the salt side inlet via the low-temperature molten salt tank 1 through the low-temperature molten salt pump 4. Then, it enters the first remelted salt heat exchanger 12 through one of the salt side outlets of the second remelted salt heat exchanger 13 via the salt inlet valve 26 of the first remelted salt heat exchanger. Finally, it enters the medium-temperature molten salt tank 2 through the other salt side outlet of the second remelted salt heat exchanger 13. The steam generated in the medium-temperature molten salt tank 2 is used to supply the high-pressure steam supply manifold.

[0110] In this embodiment, the molten salt in the first hot remelt salt heat exchanger 12 enters the high-temperature molten salt tank 3 from the salt side outlet of the first hot remelt salt heat exchanger 12 for storage.

[0111] High-temperature hot re-extraction steam enters the first hot re-molten salt heat exchanger 12 and the second hot re-molten salt heat exchanger 13 sequentially from the fifth steam inlet valve 23. After undergoing staged heat exchange with molten salt, it finally enters the low-pressure steam supply manifold.

[0112] For the molten salt exothermic side: turn on the medium-temperature molten salt pump 5, turn on the medium-temperature salt inlet valve 9, turn on the third steam inlet valve 19, and close the fourth steam inlet valve 20;

[0113] Steam in the medium-temperature molten salt tank 2 enters the molten salt steam generator through the medium-temperature salt inlet valve 9, and then enters the high-pressure steam supply manifold through the third steam inlet valve 19.

[0114] like Figure 4 As shown, this is the generator unit under peak load conditions (the pinkish-red piping indicates the flow status of each pipe under this condition):

[0115] For the molten salt absorber side: start the cryogenic molten salt pump 4, open the inlet valve 7 of the fourth-stage molten salt heat exchanger, open the first inlet valve 14, and open the second inlet valve 15; open the inlet valve 8 of the second reheat molten salt heat exchanger, and close the inlet valve 26 of the first reheat molten salt heat exchanger; open the sixth steam inlet valve 25, open the fifth steam inlet valve 23, open the first steam inlet valve 17, and close the second steam inlet valve 18;

[0116] Molten salt enters the four-extraction molten salt heat exchanger 11 sequentially from one of the low-temperature molten salt tanks 1 through the salt inlet valve 7 of the four-extraction molten salt heat exchanger. Then, it enters the first reheat molten salt heat exchanger 12 through one of the four-extraction molten salt heat exchangers 11 via the second inlet valve 15. From the salt side outlet of the first reheat molten salt heat exchanger 12, it enters the high-temperature molten salt tank 3 and then enters the molten salt steam generator, finally entering the intermediate-pressure cylinder 24. Molten salt enters the medium-temperature molten salt tank 2 through the first inlet valve 14 via another of the four-extraction molten salt heat exchangers 11. Molten salt also enters the second reheat molten salt heat exchanger 13 through the salt inlet valve 8 of the second reheat molten salt heat exchanger via another of the low-temperature molten salt tanks 1, finally entering the medium-temperature molten salt tank 2.

[0117] The high-temperature hot re-extraction steam passes through the fifth steam inlet valve 23 and enters the first hot re-molten salt heat exchanger 12 and the second hot re-molten salt heat exchanger 13, where it undergoes cascade heat exchange with the molten salt, and finally passes through the first steam inlet valve 17 to enter the high-pressure steam supply manifold.

[0118] For the molten salt exothermic side: turn on the high-temperature molten salt pump 6, turn on the high-temperature salt inlet valve 10, close the medium-temperature salt inlet valve 9, close the third steam inlet valve 19, and turn on the fourth steam inlet valve 20;

[0119] Steam in the high-temperature molten salt tank 3 enters the molten salt steam generator through the high-temperature molten salt pump 6 and the high-temperature salt inlet valve 10, and then enters the intermediate pressure cylinder 24 from the steam side outlet of the molten salt steam generator through the fourth steam inlet valve 20 for replenishment.

[0120] In this embodiment, the molten salt working medium is a binary salt.

[0121] This invention discloses a coupled multi-tank molten salt thermal storage system and method. The system innovatively designs a multi-tank molten salt thermal storage system using a binary salt as the working fluid. Based on the principles of temperature matching and tiered utilization, the system divides the process of heating molten salt with hot reheat steam into two stages. In the first heat exchange stage, the medium-temperature molten salt heated in the second heating stage is used to cool the high-temperature hot reheat steam (500-550°C), replacing the conventional water spray cooling method. The heated high-temperature molten salt in the first heat exchange stage is stored in a high-temperature molten salt tank. In the second heat exchange stage, the cooled hot reheat steam (around 400°C) from the first heat exchange stage exchanges heat with the low-temperature molten salt. A portion of the medium-temperature molten salt heated in the second heat exchange stage enters the medium-temperature molten salt tank.

[0122] In addition, during peak power generation, molten salt from the high-temperature molten salt tank is used to enter the steam generator for heat release, generating steam to supplement the intermediate-pressure cylinder and improve the unit's peak capacity.

[0123] During off-peak power generation, molten salt from the medium-temperature molten salt tank is used to enter the steam generator for heat release, generating steam which is then sent to the high-pressure gas supply header to compensate for the unit's low-load gas supply capacity.

[0124] Based on the above measures, the energy utilization rate of the molten salt energy storage system has been further improved, and the thermal economy of the system has been enhanced.

[0125] In one embodiment, a coupled multi-tank molten salt thermal storage thermodynamic method determines the molten salt pump speed, valve opening, and molten salt flow ratio in a coupled multi-tank molten salt thermal storage thermodynamic system as described above. This method is implemented through a genetic algorithm intelligent control module, which can dynamically optimize the molten salt pump speed, valve opening, and molten salt flow ratio based on real-time operating data to achieve optimal control of the system's thermal performance. Specifically, it includes the following steps:

[0126] S1. Determine and obtain the key factors affecting the thermodynamic performance of the system. The key factors include:

[0127] State variables: Unit load Hot re-extraction steam temperature Four-stage temperature Low-temperature molten salt tank outlet temperature Temperature of medium-temperature molten salt tank Temperature of high-temperature molten salt tank Flow rate of each pipeline (in (Indicates different pipelines) High-pressure steam supply pressure Low-pressure steam supply pressure ;

[0128] Decision variable: Cryogenic molten salt pump speed Medium-temperature molten salt pump speed High-temperature molten salt pump speed , opening degree of each valve (in This includes the inlet valve 7 for the four-extraction molten salt heat exchanger, the inlet valve 8 for the second hot remelted molten salt heat exchanger, the intermediate-temperature inlet valve 9, the high-temperature inlet valve 10, the first inlet valve 14, the second inlet valve 15, the first steam inlet valve 17, the second steam inlet valve 18, the third steam inlet valve 19, the fourth steam inlet valve 20, the fifth steam inlet valve 23, the sixth steam inlet valve 25, and the inlet valve 26 for the first hot remelted molten salt heat exchanger, as well as the distribution of molten salt between the heat exchangers. ,in Indicates the flow splitting node (such as the flow splitting ratio at the molten salt side outlet of the four-extraction molten salt heat exchanger 11, and the flow splitting ratio at the molten salt side outlet of the second reheat molten salt heat exchanger 13).

[0129] S2. Based on state variables and decision variables, establish a calculation model for the thermal performance indicators of the molten salt thermal storage system, wherein the thermal performance indicators include energy utilization rate. Heat loss Steam supply stability molten salt pump energy consumption ;

[0130] S3. Establish an optimized operation model with the aforementioned thermal performance indicators as the objective, encode the decision variables, and solve for the optimal combination of the decision variables based on a genetic algorithm;

[0131] S4. Based on the optimal combination of decision variables obtained from the solution, adjust the speed of the molten salt pump, the valve opening, and the molten salt diversion ratio to control the system.

[0132] In this embodiment, the calculation model for the thermodynamic performance indicators in S2 includes:

[0133] Energy utilization rate The expression is:

[0134] ;

[0135] in, This is the sum of the system's output heat energy and electrical energy. The thermal energy input to the system is determined based on the unit load in the state variables. Hot re-extraction steam temperature Four-stage temperature Flow rate of each pipeline Calculated;

[0136] Specifically: ;

[0137] In the formula, This refers to the flow rate of the hot reheat steam extraction. This is the enthalpy of the hot re-extraction steam. It is a four-pump flow rate. It is the enthalpy of four extractions, based on the state variables. Calculated;

[0138] ;

[0139] In the formula, For unit load, For high-pressure steam supply flow, The enthalpy value of high-pressure steam supply. For low-pressure steam supply flow, Enthalpy value for low-pressure steam supply;

[0140] Heat loss The expression is:

[0141] ;

[0142] in, For the first The flow rate of this pipeline The specific heat capacity of molten salt or steam. For the first The temperature difference loss of the pipeline is determined based on the temperature at each point in the state variables. Calculated;

[0143] Steam supply stability The expression is:

[0144] ;

[0145] in, This is the high-pressure steam supply pressure. For low-pressure steam supply, and The target steam supply pressure (determined by user demand). To prevent the division by zero, a small constant (taken as 0.001) is used.

[0146] Molten salt pump energy consumption The calculation formula is:

[0147] ;

[0148] in, The density of molten salt is (kg / m³). The acceleration due to gravity is 9.8 m / s². For the first The head (m) of the molten salt pump. For the first The flow rate of the molten salt pump For the first The efficiency of the molten salt pump, among which Based on the pump speed in the decision variable and valve opening This was calculated based on the pump's characteristic curve.

[0149] The specific steps for S3 are as follows:

[0150] S3.1 Set the number of iterations G, population size N, and crossover probability for the genetic algorithm. Probability of mutation In this embodiment, the number of iterations Population size Crossover probability Probability of mutation ;

[0151] S3.2 Establish an optimized operation model for the molten salt thermal storage system. The optimized operation model includes an objective function and constraints, wherein the objective function is:

[0152] ;

[0153] in, The decision variable vector includes the molten salt pump speed. Valve opening Molten salt split ratio ; These are weighting coefficients, which are dynamically adjusted based on operating conditions.

[0154] The constraints include:

[0155] Temperature constraints: To prevent the molten salt from decomposing or solidifying;

[0156] in, Take 220℃ (above the freezing point of binary salts). Take 550℃ (below the decomposition temperature of binary salts);

[0157] Pressure constraints: To ensure the quality of steam supply;

[0158] in, Take 0.8MPa (the user's minimum steam pressure). Take 2.5MPa (the upper limit of the equipment's pressure resistance).

[0159] Flow constraints: To prevent pipeline overload;

[0160] in, and Determined based on pipeline design flow rate;

[0161] Valve opening constraint: 0 ≤ ≤ 100%;

[0162] Pump speed constraint: ≤ ≤ ;

[0163] in, and Determined based on the pump's rated speed and frequency conversion range.

[0164] S3.3 Encode the decision variables with real numbers. Each individual represents a combination of decision variables. Based on the constraints, randomly generate N individuals to form an initial population. Let this initial population be the parent population.

[0165] S3.4. Substitute the decision variable values ​​of each individual in the parent population along with the real-time collected state variable values ​​into the thermal performance index calculation model described in S2 to calculate the energy utilization rate of each individual. Heat loss Steam supply stability molten salt pump energy consumption ;

[0166] S3.5. Calculate the objective function value for each individual in the parent population based on the calculation results of S3.4. Then, the fitness value of each individual in the parent population is calculated and sorted according to the fitness function;

[0167] In this embodiment, the fitness function is:

[0168] ;

[0169] in, The theoretically optimal target value or a preset target value can be determined based on historical operating data or simulation experiments. In this embodiment, the target value is taken as... =1.0, The objective function value for the current individual;

[0170] S3.6. Save the top M (M=5 in this embodiment) parent individuals with the largest fitness values ​​in the parent population. Select parent individuals from all parent individuals other than the top M with the largest fitness values ​​by roulette wheel and perform crossover and mutation operations to obtain offspring individuals. Calculate the fitness values ​​of the offspring individuals after crossover and mutation and sort them. Reinsert the offspring individuals into the parent population according to their fitness values. Select a set number of individuals to be solved to form a new parent population. Then return to S3.4.

[0171] S3.7 Repeat S3.4 to S3.6 until the number of iterations G is reached or the change in the objective function value is less than a set threshold. The resulting parent population is the optimal set of operating parameters, and the parent individuals in the parent population are the optimal combination of decision variables. The individual with the largest fitness value is selected as the optimal combination of decision variables under the current operating condition, including:

[0172] Optimal molten salt pump speed: ;

[0173] Optimal valve opening: ;

[0174] Optimal molten salt split ratio: .

[0175] The genetic algorithm optimization control method in this embodiment has multi-condition adaptive capability:

[0176] When the unit load P increases, the energy utilization rate weight in the objective function is automatically adjusted. The algorithm tends to increase the speed of the high-temperature molten salt pump and open the relevant valves to use more heat for peak power generation.

[0177] When the steam supply pressure or Steam supply stability when deviating from the target value As steam decreases, the algorithm automatically adjusts the valve opening to prioritize steam quality.

[0178] When the molten salt temperature approaches its upper limit, the temperature constraint comes into play, and the algorithm limits further heating of the high-temperature molten salt to prevent it from decomposing.

[0179] It should be noted that the above description of the disclosed embodiments enables those skilled in the art to implement or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A coupled multi-tank molten salt thermal storage system, characterized in that, include: Low-temperature molten salt tank (1), medium-temperature molten salt tank (2), high-temperature molten salt tank (3), four-extraction molten salt heat exchanger (11), first reheat molten salt heat exchanger (12), second reheat molten salt heat exchanger (13), molten salt steam generator (16), medium-pressure cylinder (24), high-pressure steam supply manifold and low-pressure steam supply manifold; in, The outlet of the low-temperature molten salt tank (1) is divided into two paths: the first path is connected to the salt side inlet of the four-extraction molten salt heat exchanger (11) through the salt inlet valve (7) of the four-extraction molten salt heat exchanger, and the second path is connected to the salt side inlet of the second-heat remelted salt heat exchanger (13) through the salt inlet valve (8) of the second-heat remelted salt heat exchanger. The salt-side outlet of the four-extraction molten salt heat exchanger (11) is divided into two paths: one path is connected to the salt-side inlet of the first reheat molten salt heat exchanger (12) through the second inlet valve (15), and the other path is connected to the medium-temperature molten salt tank (2) through the first inlet valve (14). The salt-side outlet of the second hot remelt salt heat exchanger (13) is divided into two paths: one path is connected to the medium-temperature molten salt tank (2), and the other path is connected to the salt-side inlet of the first hot remelt salt heat exchanger (12) through the salt inlet valve (26) of the first hot remelt salt heat exchanger. The salt-side outlet of the first hot remelt salt heat exchanger (12) is connected to the high-temperature molten salt tank (3). The outlets of the medium-temperature molten salt tank (2) and the high-temperature molten salt tank (3) are respectively connected to the salt-side inlet of the molten salt steam generator (16); The steam outlet of the molten salt steam generator (16) is divided into two paths, which are respectively connected to the steam inlet of the high-pressure steam supply manifold and the intermediate-pressure cylinder (24).

2. The coupled multi-tank molten salt thermal storage system according to claim 1, characterized in that, The outlet of the low-temperature molten salt tank (1) is equipped with a low-temperature molten salt pump (4), and the outlet of the medium-temperature molten salt tank (2) is equipped with a medium-temperature molten salt pump (5). The medium-temperature molten salt pump (5) is connected to the salt side inlet of the molten salt steam generator through a medium-temperature salt inlet valve (9). The outlet of the high-temperature molten salt tank (3) is equipped with a high-temperature molten salt pump (6), which is connected to the salt side inlet of the molten salt steam generator (16) through a high-temperature salt inlet valve (10).

3. The coupled multi-tank molten salt thermal storage system according to claim 1, characterized in that, A third steam inlet valve (19) is installed on the pipeline between the steam side outlet of the molten salt steam generator (16) and the high-pressure steam supply manifold, and a fourth steam inlet valve (20) is installed on the pipeline between the steam side outlet of the molten salt steam generator (16) and the steam inlet of the intermediate pressure cylinder (24).

4. The coupled multi-tank molten salt thermal storage system according to claim 1, characterized in that, The steam inlet pipe of the intermediate pressure cylinder (24) is connected to the steam side inlet of the first hot remelt salt heat exchanger (12) through the fifth steam inlet valve (23), and the steam side outlet of the first hot remelt salt heat exchanger (12) is connected to the steam side inlet of the second hot remelt salt heat exchanger (13). The steam outlet of the second reheat molten salt heat exchanger (13) is divided into two paths, which are connected to the high-pressure steam supply manifold and the low-pressure steam supply manifold respectively through the first steam inlet valve (17) and the second steam inlet valve (18).

5. A coupled multi-tank molten salt thermal storage system according to claim 1, characterized in that, The intermediate pressure cylinder (24) is connected to the steam inlet of the four-extraction molten salt heat exchanger (11) through the sixth steam inlet valve (25), and the steam outlet of the four-extraction molten salt heat exchanger (11) is connected to the steam inlet of the low-pressure steam supply manifold.

6. A coupled multi-tank molten salt thermal storage method, using a coupled multi-tank molten salt thermal storage system as described in any one of claims 2-5, characterized in that, Includes the following steps: Under normal generating load conditions of the unit: Molten salt enters the four-extraction molten salt heat exchanger (11) sequentially from one of the paths of the low-temperature molten salt tank (1), then enters the first hot remelt molten salt heat exchanger (12) through one of the paths of the four-extraction molten salt heat exchanger (11), and then enters the high-temperature molten salt tank (3) for storage from the salt side outlet of the first hot remelt molten salt heat exchanger (12); molten salt enters the medium-temperature molten salt tank (2) through the other path of the four-extraction molten salt heat exchanger (11); molten salt enters the second hot remelt molten salt heat exchanger (13) from the other path of the low-temperature molten salt tank (1), and finally enters the medium-temperature molten salt tank (2); The high-temperature hot re-extraction steam sequentially enters the first hot re-molten salt heat exchanger (12) and the second hot re-molten salt heat exchanger (13) to exchange heat with the molten salt in stages, and finally enters the high-pressure steam supply header. Under deep peak load conditions of the unit: After the molten salt enters the second hot remelted salt heat exchanger (13) sequentially from the low-temperature molten salt tank (1), it enters the first hot remelted salt heat exchanger (12) through one of the two paths of the second hot remelted salt heat exchanger (13), and enters the medium-temperature molten salt tank through the other path. The steam generated by the medium-temperature molten salt tank is used to supply the high-pressure steam supply manifold. The high-temperature hot re-extraction steam sequentially enters the first hot re-molten salt heat exchanger (12) and the second hot re-molten salt heat exchanger (13), where it undergoes cascade heat exchange with the molten salt and finally enters the low-pressure steam supply manifold. Under peak load conditions of unit power generation: Molten salt enters the four-extraction molten salt heat exchanger (11) sequentially from one of the paths of the low-temperature molten salt tank (1), then enters the first hot remelt molten salt heat exchanger (12) through one of the paths of the four-extraction molten salt heat exchanger (11), then enters the high-temperature molten salt tank (3) from the salt side outlet of the first hot remelt molten salt heat exchanger (12), and then enters the molten salt steam generator (16) from the high-temperature molten salt tank (3), and finally enters the medium-pressure cylinder (24); molten salt enters the medium-temperature molten salt tank (2) through the other path of the four-extraction molten salt heat exchanger (11); molten salt enters the second hot remelt molten salt heat exchanger (13) from the other path of the low-temperature molten salt tank (1), and finally enters the medium-temperature molten salt tank (2); The high-temperature hot re-extraction steam sequentially enters the first hot re-molten salt heat exchanger (12) and the second hot re-molten salt heat exchanger (13), where it undergoes cascade heat exchange with the molten salt, and finally enters the high-pressure steam supply manifold.

7. A coupled multi-tank molten salt thermal storage thermodynamic method according to claim 6, characterized in that, Determining the molten salt pump speed, valve opening, and molten salt diversion ratio in a coupled multi-tank molten salt thermal storage system as described in any one of claims 2-5 specifically includes the following steps: S1. Determine and obtain the key factors affecting the thermodynamic performance of the system. The key factors include: State variables: Unit load Hot re-extraction steam temperature Four-stage temperature Low-temperature molten salt tank outlet temperature Temperature of medium-temperature molten salt tank Temperature of high-temperature molten salt tank Flow rate of each pipeline High-pressure steam supply pressure Low-pressure steam supply pressure ; Decision variable: Cryogenic molten salt pump speed Medium-temperature molten salt pump speed High-temperature molten salt pump speed , opening degree of each valve And the distribution of molten salt between the heat exchangers ,in Indicates a branch node; S2. Based on the aforementioned state variables and decision variables, establish a calculation model for the thermal performance indicators of the molten salt thermal storage system, wherein the thermal performance indicators include energy utilization rate. Heat loss Steam supply stability molten salt pump energy consumption ; S3. Establish an optimized operation model with the aforementioned thermal performance indicators as the objective, encode the decision variables, and solve for the optimal combination of the decision variables based on a genetic algorithm; S4. Based on the optimal combination of decision variables obtained from the solution, adjust the speed of the molten salt pump, the valve opening, and the molten salt diversion ratio to control the system.

8. The coupled multi-tank molten salt thermal storage thermodynamic method according to claim 7, characterized in that, The calculation model for the thermodynamic performance indicators mentioned in S2 includes: Energy utilization rate The expression is: ； in, This is the sum of the system's output heat energy and electrical energy. The thermal energy input to the system is determined based on the unit load in the state variables. Hot re-extraction steam temperature Four-stage temperature Flow rate of each pipeline Calculated; Heat loss The expression is: ； in, For the first The flow rate of this pipeline The specific heat capacity of molten salt or steam. For the first The temperature difference loss of the pipeline is determined based on the temperature at each point in the state variables. Calculated; Steam supply stability The expression is: ； in, This is the high-pressure steam supply pressure. For low-pressure steam supply, and For the target steam supply pressure, To prevent the division of zero by a small constant; Molten salt pump energy consumption The calculation formula is: ； in, The density of molten salt, It is the acceleration due to gravity. For the first The head of the molten salt pump For the first The flow rate of the molten salt pump For the first The efficiency of the molten salt pump, among which Based on the pump speed in the decision variable and valve opening Calculated.

9. A coupled multi-tank molten salt thermal storage thermodynamic method according to claim 7, characterized in that, The specific steps for S3 are as follows: S3.1 Set the number of iterations G, population size N, and crossover probability for the genetic algorithm. Probability of mutation ; S3.2 Establish an optimized operation model for the molten salt thermal storage system. The optimized operation model includes an objective function and constraints, wherein the objective function is: ； in, The decision variable vector includes the molten salt pump speed. Valve opening Molten salt split ratio ; These are weighting coefficients, which are dynamically adjusted based on operating conditions. The constraints include: Temperature constraints: To prevent the molten salt from decomposing or solidifying; Pressure constraints: To ensure the quality of steam supply; Flow constraints: To prevent pipeline overload; Valve opening constraint: 0 ≤ ≤ 100%; Pump speed constraint: ≤ ≤ ; S3.3 Encode the decision variables with real numbers. Each individual represents a combination of decision variables. Based on the constraints, randomly generate N individuals to form an initial population. Let this initial population be the parent population. S3.

4. Substitute the decision variable values ​​of each individual in the parent population along with the real-time collected state variable values ​​into the thermal performance index calculation model described in S2 to calculate the energy utilization rate of each individual. Heat loss Steam supply stability molten salt pump energy consumption ; S3.

5. Calculate the objective function value for each individual in the parent population based on the calculation results of S3.

4. Then, the fitness value of each individual in the parent population is calculated and sorted according to the fitness function; S3.

6. Save the top M parent individuals with the largest fitness values ​​in the parent population. Select parent individuals from all parent individuals other than the top M parent individuals with the largest fitness values ​​through a roulette wheel and perform crossover and mutation operations to obtain offspring individuals. Calculate the fitness values ​​of the offspring individuals after crossover and mutation and sort them. Reinsert the offspring individuals into the parent population according to their fitness values. Select a set number of individuals to be solved to form a new parent population, and then return to S3.

4. S3.7 Repeat S3.4 to S3.6 until the number of iterations G is reached or the change in the objective function value is less than the set threshold. The resulting parent population is the optimal set of operating parameters, and the parent individuals in the parent population are the optimal combination of decision variables.

10. A coupled multi-tank molten salt thermal storage thermodynamic method according to claim 9, characterized in that, The fitness function is: ； in, For the theoretically optimal target value or the preset target value, This represents the objective function value for the current individual.

Images