Fused salt heat storage and Carnot cell combined coal-fired unit peak regulation operation method, device, equipment, medium and product

Abstract

The invention discloses a fused salt heat storage and Carnot cell combined coal-fired unit peak-load regulation operation method, device and equipment, a medium and a product, and relates to the field of unit peak-load regulation operation. Acquiring information data; based on a power regulation demand prediction model, performing peak regulation demand prediction according to the information data to obtain a prediction result; the power regulation demand prediction model is obtained by adopting a multi-objective optimization model and performing time sequence analysis on a long-short-term memory network model; determining an energy scheduling strategy based on the prediction result; the energy scheduling strategy comprises a heat storage power coordination instruction and a heat release power coordination instruction; and according to the energy scheduling strategy, operation adjustment is conducted on the coal-fired unit, the fused salt heat storage subsystem and the Carnot battery subsystem based on the control system. The invention aims to improve the peak regulation performance of the coal-fired unit.

Description

Technical Field

[0001] This application relates to the field of peak-shaving operation of power units, and in particular to a method, apparatus, equipment, medium and product for peak-shaving operation of coal-fired power units that combines molten salt thermal storage and Carnot batteries. Background Technology

[0002] With the rapid development of renewable energy, the intermittent and random nature of renewable energy power generation has led to a corresponding increase in the peak-shaving demand of the power system. The role of coal-fired power generation will gradually shift from being the main power supply source to a supporting and regulating power source. Currently, to improve the flexibility of existing coal-fired units, especially to reduce the minimum operating load, the main method is to couple molten salt thermal storage systems. However, molten salt thermal storage systems have high thermal inertia and slow start-up and power regulation speeds, limiting the peak-shaving performance of coal-fired units. Summary of the Invention

[0003] The purpose of this application is to provide a method, apparatus, equipment, medium, and product for peak-shaving operation of coal-fired power units that combines molten salt thermal storage and Carnot batteries, which can improve the peak-shaving performance of coal-fired power units.

[0004] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a method for peak-shaving operation of a coal-fired power unit combining molten salt thermal storage and a Carnot battery. This method is applied to a coal-fired power unit coupled with a molten salt thermal storage system. The molten salt thermal storage system includes: a coal-fired power unit, a molten salt thermal storage subsystem, a Carnot battery subsystem, a coupling interface unit, and a control system. The control system is connected to the molten salt thermal storage subsystem, the Carnot battery subsystem, and the coal-fired power unit respectively through the coupling interface unit. The method for peak-shaving operation of coal-fired power units combining molten salt thermal storage and Carnot batteries includes: Acquire information data; the information data includes: AGC control commands and real-time operating data of the coal-fired unit; the AGC control commands are control commands generated by the power grid dispatch center based on the real-time frequency of the power system and the power deviation of the tie line, based on the control system; the operating data includes: boiler load, main steam pressure, flow rate, and turbine speed; Based on the power regulation demand prediction model, peak shaving demand is predicted according to the information data to obtain the prediction result; the power regulation demand prediction model is obtained by using a multi-objective optimization model and performing time series analysis on a long short-term memory network model. An energy scheduling strategy is determined based on the prediction results; the energy scheduling strategy includes: thermal storage power coordination command and heat release power coordination command. According to the energy dispatch strategy, the operation of the coal-fired unit, the molten salt thermal storage subsystem, and the Carnot battery subsystem are adjusted based on the control system.

[0005] In one embodiment, the mathematical expression corresponding to the power regulation demand prediction model is: ; in, For the future Forecasted power regulation demand at any given time; It is a long short-term memory network model; These are used to train weights to capture the nonlinear timing relationship between runtime data and AGC control commands; for The running vector corresponding to the running data at any given time; for The instruction vector corresponding to the AGC control instruction at any given time; for The feedforward vector at time step; This is a correction term for the residual.

[0006] In one embodiment, the mathematical expression corresponding to the multi-objective optimization model is: ; ; ; ; in, For dynamic power allocation coefficient; Optimize function vectors for multiple objectives; Coordination command for total heat storage / release power; To minimize the cumulative error during the adjustment process; To control the cycle; To minimize operating costs; For the penalty function; For safety parameters; 、 All are cost coefficients; For system round-trip efficiency; for The actual output power of the coal-fired power unit at any given time; for AGC target power command issued by the power grid dispatch center at any time; The electrical energy consumed by the compressor; The electrical energy generated by the Rankine cycle expander; For the first Penalty weighting coefficients for each security parameter; For the first The maximum allowed value for each security parameter.

[0007] In one embodiment, the expression corresponding to the prediction result is: ; in, The final determined power allocation ratio; This represents the maximum value of the power allocation coefficient; The load change rate requirement for AGC control commands; The predicted rate threshold; It is an interpolation function; The state of charge of the molten salt thermal storage system; This is a forecast of power regulation demand. This represents the expected duration of peak shaving.

[0008] In one embodiment, the expression corresponding to the energy scheduling strategy is: ; in, This is the power command vector corresponding to the energy dispatch strategy; For total heat storage / release power coordination command; For dynamic power allocation coefficient; For compressor power setpoint; This is the setpoint for the opening of the thermal storage regulating valve; This is a transpose.

[0009] In one embodiment, based on the energy dispatch strategy, the operation of the coal-fired unit, the molten salt thermal storage subsystem, and the Carnot battery subsystem is adjusted by the control system, specifically including: When the energy dispatch strategy is a thermal storage power coordination command, the system performs coupled thermal storage of heat pump cycle and molten salt, as well as coupled thermal storage of extracted steam and molten salt, based on the control system. The molten salt thermal storage subsystem includes a molten salt tank, a molten salt pump, and a molten salt heat exchanger. The Carnot battery subsystem includes a heat pump cycle unit and a Rankine cycle unit. The heat pump cycle unit includes a compressor, an evaporator, a regenerator, and a throttling valve. The Rankine cycle unit includes an expander, a generator, a condenser, and a circulating pump. The coupling interface unit includes a thermal storage regulating valve, a feedwater distribution valve, a sampling interface, a grid connection interface, and a molten salt distribution interface. In the coupled heat pump cycle and molten salt heat storage stage: The control system controls the power input interface of the coal-fired unit to process the open state, so that a portion of the electrical energy output from the generator in the coal-fired unit is diverted to the compressor in the heat pump cycle unit. Based on the control system and the compressor inlet temperature and compressor inlet pressure Dynamically calculate compressor pressure ratio With the set compressor outlet temperature and isentropic efficiency as control targets, the compressor drives the argon working medium to exchange heat with the cold molten salt in the molten salt heat exchanger contained in the molten salt thermal storage subsystem at 290°C. The control system adjusts the frequency of the molten salt pump in the molten salt storage subsystem and controls the flow rate of the cold molten salt to ensure that the cold molten salt is heated to the target temperature of 560°C and then stored in the hot tank. The argon working fluid then flows through the heat pump circulation unit, which includes a regenerator and a throttling valve to cool and depressurize, so as to complete the cycle. In the coupled thermal storage stage of steam extraction molten salt: The control system controls the thermal storage regulating valve in the coupling interface unit to be in the open state, and diverts a portion of the main steam to the turbine to the molten salt heat exchanger. At the same time as the steam is diverted, the control system controls the feedwater diversion valve in the coupling interface unit to divert a portion of the boiler feedwater to the same molten salt heat exchanger. The steam condenses in the molten salt heat exchanger and transfers heat to the molten salt, while the condensate returns to the condenser. When the energy dispatch strategy is a heat release power coordination command, the Rankine cycle and molten salt are coupled for heat release, and the molten salt heating feedwater is coupled for heat release, based on the control system. In the coupled heat release stage of the Rankine cycle and molten salt: The system controls the start of the Rankine cycle unit and pumps the 560°C high-temperature molten salt in the hot tank to the evaporator contained in the heat pump cycle unit. Based on the control system and the evaporator inlet pressure and pressure ratio Adjusting the regulating valve before the expander in the Rankine cycle unit allows the working fluid water to absorb heat in the evaporator and turn into steam, driving the expander to rotate the generator in the Rankine cycle unit and generate electricity; the generated electricity is connected to the power grid through the grid connection interface in the coupling interface unit, while the molten salt that has released heat and cooled down flows back to the cold tank. Molten salt heating feedwater coupled with heat release stage: Based on the control system, the control coupling interface unit includes a feedwater diversion valve that is in the open state, so that a portion of the feedwater with a temperature lower than the set temperature is diverted to the molten salt heat exchanger included in the molten salt thermal storage subsystem. After the feedwater is heated by the molten salt with a temperature higher than the set temperature, it becomes feedwater with a temperature higher than the set temperature, and then merges with the main feedwater to enter the boiler.

[0010] Secondly, this application provides a peak-shaving operation device for coal-fired power units that combines molten salt thermal storage and Carnot batteries, comprising: The information data acquisition module is used to acquire information data, including: AGC control commands and real-time operating data of the coal-fired power unit; the AGC control commands are control commands generated by the power grid dispatch center based on the real-time frequency of the power system and the power deviation of the tie line, based on the control system; the operating data includes: boiler load, main steam pressure, flow rate, and turbine speed. The demand forecasting module is used to predict peak-shaving demand based on the information data according to the power regulation demand forecasting model, and to obtain the forecasting results; the power regulation demand forecasting model is obtained by performing time series analysis on the long short-term memory network model using a multi-objective optimization model. An energy scheduling strategy determination module is used to determine an energy scheduling strategy based on the prediction results; the energy scheduling strategy includes: thermal storage power coordination command and heat release power coordination command. The operation adjustment module is used to adjust the operation of the coal-fired unit, the molten salt thermal storage subsystem, and the Carnot battery subsystem based on the energy dispatch strategy and the control system.

[0011] Thirdly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described method for peak-shaving operation of a coal-fired unit combining molten salt thermal storage and Carnot batteries.

[0012] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method for peak-shaving operation of a coal-fired unit combining molten salt thermal storage and Carnot batteries.

[0013] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method for peak-shaving operation of a coal-fired unit combining molten salt thermal storage and Carnot batteries.

[0014] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a method, apparatus, equipment, medium, and product for peak-shaving operation of a coal-fired power unit combining molten salt thermal storage and Carnot batteries. Based on a power regulation demand prediction model, peak-shaving demand is predicted using information data to obtain prediction results. The power regulation demand prediction model in this application is obtained by performing time series analysis on a long short-term memory network model using a multi-objective optimization model. An energy dispatch strategy is determined based on the prediction results. The energy dispatch strategy includes: thermal storage power coordination commands and heat release power coordination commands. According to the energy dispatch strategy, the operation of the coal-fired power unit, the molten salt thermal storage subsystem, and the Carnot battery subsystem is regulated by the control system to achieve electricity-heat-electricity conversion. This application's collaborative peak-shaving based on the Carnot battery subsystem coupled with the molten salt thermal storage subsystem can significantly improve the load increase / decrease rate of the coal-fired power unit and effectively overcome the problem of limited peak-shaving capacity caused by the single form of steam extraction molten salt thermal storage, thereby improving the peak-shaving performance of the coal-fired power unit. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A flowchart for a peak-shaving operation method for coal-fired power units that combine molten salt thermal storage and Carnot batteries; Figure 2 This is a schematic diagram of the thermal energy storage control process; Figure 3 This is a schematic diagram of the heat release control process; Figure 4 A structural diagram of a peak-shaving operation unit for a coal-fired power plant that combines molten salt thermal storage and a Carnot battery. Figure 5 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] To compensate for the insufficient peak-shaving capacity of molten salt thermal energy storage, Carnot battery technology has become a key solution. During energy storage, electrical energy is converted into thermal energy through a heat pump cycle unit; during energy release, thermal energy is converted back into electrical energy through a Rankine cycle unit, thus achieving an electro-thermal-electricity conversion. Carnot battery coupled with molten salt thermal energy storage for synergistic peak-shaving has the following unique advantages: Firstly, during thermal storage, the compressor directly consumes electrical energy output from the coal-fired generator for thermal storage; during thermal release, the expander utilizes the stored heat to generate electricity, which is directly fed into the grid, significantly improving the load increase / decrease rate of the coal-fired unit. Secondly, under high-load operating conditions of the coal-fired generator unit, although heat pump thermal energy storage has a certain negative impact on the overall system efficiency, it exhibits superior performance compared to molten salt thermal energy storage in terms of peak-shaving capacity and depth, effectively overcoming the limited peak-shaving capacity caused by the single form of extraction molten salt thermal energy storage.

[0019] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] In one exemplary embodiment, a method for peak-shaving operation of a coal-fired power unit combining molten salt thermal storage and a Carnot battery is provided. This method is applied to a coal-fired power unit coupled with a molten salt thermal storage system. The molten salt thermal storage system includes a coal-fired power unit, a molten salt thermal storage subsystem, a Carnot battery subsystem, a coupling interface unit, and a control system. The control system is connected to the molten salt thermal storage subsystem, the Carnot battery subsystem, and the coal-fired power unit respectively through the coupling interface unit.

[0021] The molten salt thermal energy storage subsystem includes a molten salt storage tank, a molten salt pump, and a molten salt heat exchanger; the Carnot battery subsystem includes a heat pump circulation unit and a Rankine circulation unit; the heat pump circulation unit includes a compressor, an evaporator, a regenerator, and a throttling valve; the Rankine circulation unit includes an expander, a generator, a condenser, and a circulating pump; the coupling interface unit includes a thermal energy storage regulating valve, a feedwater distribution valve, a sampling interface, a grid connection interface, and a molten salt distribution interface.

[0022] like Figure 1 As shown, the peak-shaving operation method of the coal-fired unit combining molten salt thermal storage and Carnot battery includes: Step 100: Acquire information data. Information data includes: AGC control commands and real-time operating data of the coal-fired unit; AGC control commands are control commands generated by the power grid dispatch center based on the real-time frequency of the power system and tie-line power deviation, based on the control system; operating data includes: boiler load, main steam pressure, flow rate, and turbine speed.

[0023] Step 200: Based on the power regulation demand forecasting model, peak-shaving demand is predicted according to the information data to obtain the prediction results. The power regulation demand forecasting model is obtained by performing time series analysis on a long short-term memory network model using a multi-objective optimization model.

[0024] The mathematical expression for the power regulation demand forecasting model is: .

[0025] in, For the future Forecasted power regulation demand at any given time, in MW; It is a long short-term memory network model; These are used to train weights to capture the nonlinear timing relationship between runtime data and AGC control commands; for The running vector corresponding to the running data at any given time; for The instruction vector corresponding to the AGC control instruction at any given time; for The feedforward vector at time step; This is a correction term for the residual.

[0026] The mathematical expression for the multi-objective optimization model is: .

[0027] .

[0028] .

[0029] .

[0030] in, For dynamic power allocation coefficient; Optimize function vectors for multiple objectives; Coordination command for total heat storage / release power; To minimize the cumulative error during the adjustment process; To control the cycle; To minimize operating costs; For the penalty function; For safety parameters; 、 All are cost coefficients; For system round-trip efficiency; for The actual output power of the coal-fired power unit at any given time; for AGC target power command issued by the power grid dispatch center at any time; The electrical energy consumed by the compressor, in MW; The electrical energy generated by the Rankine cycle expander (i.e., the expander in the Rankine cycle unit), in MW; For the first Penalty weighting coefficients for each security parameter; For the first The maximum allowed value for each security parameter.

[0031] The expression corresponding to the prediction result is: .

[0032] in, The final determined power allocation ratio; This represents the maximum value of the power allocation coefficient, which typically indicates that the Carnot battery subsystem is prioritized or fully utilized. The load change rate requirement for AGC control commands; The predicted rate threshold is used to determine whether a fast response is required; It is an interpolation function that dynamically calculates the power allocation ratio based on multiple parameters; The state of charge of the molten salt thermal storage system; The power regulation demand forecast is in MW; This represents the expected duration of peak shaving.

[0033] Step 300: Determine the energy dispatch strategy based on the prediction results. The energy dispatch strategy includes: thermal storage power coordination commands and heat release power coordination commands.

[0034] The expression corresponding to the energy dispatch strategy is: .

[0035] in, This is the power command vector corresponding to the energy dispatch strategy; For total heat storage / release power coordination command; For dynamic power allocation coefficient; For compressor power setpoint; This is the setpoint for the opening of the thermal storage regulating valve; This is a transpose.

[0036] Step 400: Based on the energy dispatch strategy, adjust the operation of the coal-fired unit, the molten salt thermal storage subsystem, and the Carnot battery subsystem according to the control system.

[0037] As an optional implementation method, based on the energy dispatch strategy, the operation of the coal-fired unit, the molten salt thermal storage subsystem, and the Carnot battery subsystem is adjusted according to the control system, specifically including: When the energy dispatch strategy is a thermal storage power coordination command, the system performs coupled thermal storage of heat pump cycle and molten salt, as well as coupled thermal storage of steam extraction molten salt.

[0038] In the coupled heat pump cycle and molten salt heat storage stage: The control system controls the power input interface of the coal-fired unit to process the open state, so that a portion of the electrical energy output from the generator in the coal-fired unit is diverted to the compressor in the heat pump cycle unit.

[0039] Based on the control system and the compressor inlet temperature and compressor inlet pressure Dynamically calculate compressor pressure ratio With the set compressor outlet temperature and isentropic efficiency as control targets, the compressor drives the argon working medium to exchange heat with the cold molten salt in the molten salt heat exchanger contained in the molten salt thermal storage subsystem at 290°C.

[0040] The control system adjusts the frequency of the molten salt pump in the molten salt thermal storage subsystem and controls the flow rate of the cold molten salt to ensure that the cold molten salt is heated to the target temperature of 560°C and then stored in the hot tank. The argon working medium then flows through the heat pump circulation unit, which includes a regenerator and a throttling valve to cool and depressurize, thus completing the cycle.

[0041] In the coupled thermal storage stage of steam extraction molten salt: The control system controls the thermal storage regulating valve in the coupling interface unit to be in the open state, and diverts a portion of the main steam destined for the turbine to the molten salt heat exchanger. At the same time as the steam is diverted, the control system controls the feedwater diversion valve in the coupling interface unit to divert a portion of the boiler feedwater to the same molten salt heat exchanger. The steam condenses in the molten salt heat exchanger and transfers heat to the molten salt, while the condensate returns to the condenser.

[0042] When the energy dispatch strategy is a heat release power coordination command, the Rankine cycle and molten salt are coupled for heat release, and molten salt heating feedwater is coupled for heat release, based on the control system.

[0043] In the coupled heat release stage of the Rankine cycle and molten salt: The control system starts the Rankine cycle unit and pumps the 560°C high-temperature molten salt in the hot tank to the evaporator contained in the heat pump cycle unit.

[0044] Based on the control system and the evaporator inlet pressure and pressure ratio Adjusting the regulating valve before the expander in the Rankine cycle unit allows the working fluid water to absorb heat in the evaporator and turn into steam, driving the expander to rotate the generator in the Rankine cycle unit and generate electricity; the generated electricity is connected to the power grid through the grid connection interface in the coupling interface unit, while the molten salt that has released heat and cooled down flows back to the cold tank.

[0045] Molten salt heating feedwater coupled with heat release stage: Based on the control system, the control coupling interface unit includes a feedwater diversion valve that is in the open state, so that a portion of the feedwater with a temperature lower than the set temperature is diverted to the molten salt heat exchanger included in the molten salt thermal storage subsystem. After the feedwater is heated by the molten salt with a temperature higher than the set temperature, it becomes feedwater with a temperature higher than the set temperature, and then merges with the main feedwater to enter the boiler.

[0046] This application analyzes the working fluid state, parameter changes, and energy conversion process during the operation of a coal-fired power unit coupled with a molten salt thermal storage system, and designs a peak-shaving operation method for coal-fired power units combining molten salt thermal storage and Carnot batteries. To ensure the thermal storage system simultaneously possesses the advantages of large storage capacity, long duration, and fast response speed, and better meets the peak-shaving needs of the power grid, a heat pump cycle unit, a molten salt storage tank, and a Rankine engine (Rankine cycle unit) are added to the original molten salt thermal storage system. This retains the long-duration and large storage capacity characteristics of molten salt thermal storage while incorporating the high round-trip efficiency of Carnot battery thermal storage. When the coal-fired power unit needs to continuously reduce load for an extended period, the heat pump thermal storage intervenes first. The heat pump reduces the unit load by directly consuming the electrical energy output from the coal-fired power unit's generator; this process has a relatively fast response speed. Secondly, the extracted steam thermal storage is put into operation, reducing the amount of steam entering the turbine to reduce the turbine's output, ultimately leading to a reduction in the unit load; this process has a slower response speed.

[0047] When the grid load is at its lowest point, coal-fired power generating units enter low-load operation mode, reducing turbine output. However, due to the slow response speed of the boiler, it typically takes about 5-8 minutes for the boiler to respond after an AGC control command is issued, which cannot meet the frequent adjustment needs of the grid side. In addition, to ensure stable combustion and safety requirements under the lowest operating conditions of the unit, the boiler operating limit is 30% THA. Therefore, to improve the flexibility of existing coal-fired units, especially to reduce the minimum operating load, coupling coal-fired units with energy storage systems is a better solution.

[0048] The physical structure of the system in this application includes the following core components: Molten salt thermal energy storage subsystem: includes molten salt storage tank, molten salt pump, and molten salt heat exchanger, used to directly store and release thermal energy from steam.

[0049] Carnot battery subsystem: includes heat pump cycle unit (compressor, evaporator, regenerator, expansion valve) and Rankine cycle unit (expander, generator, condenser, circulation pump).

[0050] Coupling interface unit: (thermal storage regulating valve, water supply diversion valve, sampling interface, grid connection interface, molten salt distribution interface).

[0051] Control system: Used to coordinate the switching and power distribution of the heat storage / release process, and adopts a hierarchical decision-making structure.

[0052] This system achieves the traditional molten salt thermal energy storage function by coupling valves with the steam and feedwater systems of coal-fired power units. Coupling scheme: 1. Coupling with steam extraction molten salt thermal storage (thermal storage process), i.e., the coupled thermal storage stage of steam extraction molten salt: Coupling interface: Thermal storage regulating valve. This valve is installed on the extraction steam or main steam pipeline of the steam turbine.

[0053] Coupling process: During thermal storage, the thermal storage regulating valve is opened, diverting a portion of the high-grade steam to the molten salt heat exchanger. The steam condenses in the molten salt heat exchanger, transferring heat to the molten salt, while the condensate returns to the condenser. This reduces the steam intake of the turbine, thereby lowering the unit load.

[0054] 2. Coupling with the water supply system (heat release process), i.e.: molten salt heating water supply coupled with heat release stage: Coupling interface: Feedwater diversion valve. This valve is installed on the high-pressure feedwater pipeline after the boiler feedwater pump.

[0055] Coupling process: During heat release, the feedwater diversion valve is opened, diverting a portion of the low-temperature feedwater to the molten salt heat exchanger. After being heated by the high-temperature molten salt, the feedwater becomes high-temperature feedwater, which then merges with the main feedwater after the high-pressure heater and enters the boiler. Because part of the feedwater has been preheated, the steam extraction requirement of the high-pressure heater is reduced, allowing more steam to perform work in the turbine and increasing the unit load.

[0056] 3. Coupling of heat pump cycle and molten salt (thermal storage process), i.e., the coupled thermal storage stage of heat pump cycle and molten salt: Coupling interface: Molten salt heat exchanger. The molten salt heat exchanger here is the key device connecting the Carnot cell working fluid (such as argon) to the shared molten salt.

[0057] Coupling process: During heat storage, the working fluid in the heat pump cycle is driven by a compressor. The high-temperature, high-pressure working fluid is not directly discharged, but enters a molten salt heat exchanger, transferring its heat to the low-temperature molten salt from the cold tank. After cooling, the working fluid continues to circulate, while the molten salt, having absorbed heat, is pumped to the hot tank for storage.

[0058] 4. Coupling of the Rankine cycle and molten salt (heat release process), i.e., the heat release stage of the coupling of the Rankine cycle and molten salt: Coupling interface: Evaporator. The evaporator here is another key device connecting the Carnot battery working fluid (such as water) to the shared molten salt.

[0059] Coupling process: During heat release, high-temperature molten salt from the hot tank is pumped to the evaporator, heating the working fluid water in the Rankine cycle unit, turning it into high-temperature, high-pressure steam. The steam drives the expander to generate electricity, while the molten salt, after releasing heat and cooling, flows back to the cold tank.

[0060] Specifically, the heat storage / release control process: like Figure 2 As shown, when the grid load is at a low point and the coal-fired power unit needs to reduce its load for thermal storage, the control system executes the following steps: (1) First stage (Carno battery heat pump heat storage), namely the coupled heat pump cycle and molten salt heat storage stage: when the system optimization level determines that a rapid load reduction is required, the Carno battery subsystem response time is less than 2 minutes, and it quickly intervenes.

[0061] Power intake upon startup: The control system immediately diverts a portion of the electrical energy from the generator output of the coal-fired unit through the power intake interface to drive the compressor in the heat pump cycle unit. The compressor uses variable frequency start-up, and the speed smoothly increases from zero to the target value within 1 minute.

[0062] Control parameters: The control system uses the compressor inlet temperature as the control parameter. and compressor inlet pressure Dynamic calculation of compressor pressure ratio The control targets are a compressor outlet temperature of 589℃ and an isentropic efficiency of 0.88 to ensure stable equipment output parameters.

[0063] Heat exchange and storage: High-temperature, high-pressure argon working fluid exchanges heat with cold molten salt at 290°C in a molten salt heat exchanger. The control system regulates the molten salt pump frequency and controls the flow rate of the cold molten salt to ensure it is heated to the target temperature of 560°C before being stored in the hot tank. The circulating working fluid (argon working fluid) then flows through a regenerator and a throttling valve to cool and depressurize, completing the cycle. This process rapidly reduces the load by directly consuming electrical energy from the generator side, compensating for the boiler's 5-8 minute response delay.

[0064] (2) The second stage (extraction steam storage), that is, the coupled heat storage stage of extraction steam and molten salt: After the load of the heat pump cycle unit in the battery subsystem reaches the preset value or the operation is stable, the system optimization level determines that further deep load reduction is needed. At this time, molten salt extraction steam storage is put into operation smoothly.

[0065] Steam diversion control: The control system slowly opens the heat storage regulating valve to divert a portion of the high-grade main steam that was originally going to the steam turbine to the molten salt heat exchanger.

[0066] Feedwater and molten salt coordination: While the steam is being diverted, the feedwater diversion valve is adjusted to direct a portion of the boiler feedwater to the same molten salt heat exchanger. High-temperature steam heats the low-temperature feedwater here, condenses itself, and is then discharged into the condenser; while the high-temperature molten salt transfers its heat to the feedwater, cools itself, and flows into the cold tank. The energy balance of this process is given by the formula... Strict monitoring.

[0067] in, The mass flow rate of molten salt is kg / s. The enthalpy of molten salt at the inlet of the molten salt heat exchanger, in kJ / kg; The enthalpy of molten salt at the outlet of the molten salt heat exchanger, in kJ / kg; The mass flow rate is expressed in kg / s. Enthalpy of feedwater at the inlet of molten salt heat exchanger, kJ / kg; , where is the feedwater specific enthalpy at the outlet of the molten salt heat exchanger, in kJ / kg.

[0068] like Figure 3 As shown, when the grid load recovers and coal-fired power units need to quickly increase their output to release heat, the control system executes the following steps: (1) First stage (Carno battery Rankine cycle heat release), that is, the coupled heat release stage of Rankine cycle and molten salt: when the system optimization level determines that a rapid load increase is required, the Rankine cycle unit in the Carno battery subsystem generates electricity rapidly.

[0069] Heat source release: The control system immediately starts the Rankine cycle unit, pumping the 560°C high-temperature molten salt in the hot tank to the evaporator.

[0070] Power generation: The working fluid, water, absorbs heat in the evaporator and transforms into high-temperature, high-pressure steam, which drives the expander to perform work. The control system precisely controls the inlet pressure by adjusting the regulating valve before the expander. and pressure ratio To optimize work efficiency. Expander outlet temperature. From the formula Perform prediction and calibration. Among them, The temperature of the working fluid at the inlet of the expander; It is the variability index of the working fluid.

[0071] Grid connection: The expander drives the generator to rotate, and the generated electrical energy is quickly connected to the power grid through the grid connection interface, realizing an instantaneous increase in load.

[0072] (2) The second stage (molten salt heating feedwater heat release), namely the molten salt heating feedwater coupled heat release stage: after the heat release process of the Carnot battery subsystem proceeds smoothly, the auxiliary steam system of the molten salt thermal storage subsystem begins to output power.

[0073] Integrated feedwater heating: The control system regulates valves (feedwater diversion valves) to guide high-temperature molten salt into the feedwater heating process. Low-temperature feedwater is diverted by the diverter and then guided to the molten salt heat exchanger to be heated into high-temperature feedwater.

[0074] Turbine Output Boost: This preheated high-temperature feedwater merges with the main feedwater after the high-pressure heater before entering the boiler. Because the feedwater temperature has increased, the boiler requires less fuel, or more importantly, the amount of steam needed for extraction to the high-pressure heater is reduced. This means more steam remains in the turbine to perform work, thus smoothly increasing the turbine's output. The control system ensures that this process does not impact boiler operation through precise regulation of feedwater flow and temperature.

[0075] The core innovation of this application lies in its hierarchical intelligent control architecture, which ensures seamless coordination between the molten salt thermal storage subsystem (large capacity, slow response) and the Carnot battery subsystem (high efficiency, fast response). The control system is divided into three layers, with task decomposition from top to bottom and status feedback from bottom to top: 1. System Optimization Level: This level receives AGC control commands from the power grid dispatch center and integrates real-time operating data of coal-fired units, such as boiler load, main steam pressure, flow rate, and turbine speed. Based on a multi-objective optimization algorithm of model predictive control, it predicts peak-shaving demand over a future period, i.e., the magnitude and duration of load reduction required. Based on the prediction results, an overall energy dispatch strategy is formulated.

[0076] 2. System Coordination Level: This level receives power coordination commands for heat storage / release from the system optimization level and dynamically allocates them to the molten salt thermal storage subsystem and the Carnot battery subsystem. It then manages the opening commands of the thermal storage regulating valves and feedwater diversion valves. During thermal storage, the coordination level, based on the principles of rapid response and smooth transition, first allocates most of the power coordination commands to the heat pump cycle unit in the Carnot battery subsystem, enabling its rapid startup. After the load of the heat pump cycle unit stabilizes, the power share of molten salt extraction thermal storage is gradually increased to achieve a smooth and deep load reduction. During heat release, the Rankine cycle unit in the Carnot battery subsystem is prioritized for rapid power generation, while simultaneously smoothly incorporating the steam increment brought by the heat release from the molten salt thermal storage.

[0077] 3. Equipment Control Level: This level directly controls the operation of field equipment. Based on instructions from the coordination level, the controller (control system) precisely adjusts the compressor speed to control its power consumption and circulating working fluid parameters; controls the frequency converter of the molten salt pump to regulate the molten salt flow rate; and quickly switches the thermal storage regulating valve and feedwater distribution valve. Simultaneously, this level collects real-time thermal parameters at the equipment inlet and outlet using high-precision temperature, pressure, and flow sensors and feeds them back to the upper-level system.

[0078] This application proposes a Model Predictive Control (MPC) framework, based on the power allocation logic of time-series coordination and capability complementarity, combining Long Short-Term Memory (LSTM) networks and Autoregressive Integrated Moving Average (ARIMA) prediction with NSGA-II multi-objective optimization. This MPC is essentially a power regulation demand prediction model, derived by performing time-series analysis on the LSTM network model using a multi-objective optimization model. The power regulation demand prediction model is used to solve the coordinated control problem of the molten salt thermal storage subsystem and the Carnot battery subsystem. The LSTM neural network is used to capture nonlinear relationships; ARIMA is used to improve prediction accuracy. The effectiveness of the model algorithm is based on a clear definition of its input and output variables. The following is the variable definition process in the above model.

[0079] Multiple input vectors: Real-time running vector (Determined by real-time operational data): .

[0080] in, Real-time generator output (MW); Main steam flow rate (Kg / s); Main steam pressure (MPa); The turbine valve opening degree (%); The liquid level height in the molten salt tank (%). The liquid level height (%) in the cold molten salt tank.

[0081] External instruction vector (Determined by AGC control instructions): .

[0082] in: The target load for AGC is (MW). The AGC load change rate requirement (MW / min).

[0083] Predicting feedforward vector : .

[0084] in, For the future Forecast values ​​of power grid load for the specified time period; For the future Forecast values ​​of renewable energy output during the specified time period. For a moment. This is a transpose.

[0085] Optimize the output vector: .

[0086] in, Total heat storage / release capacity coordination command (MW); For dynamic power allocation coefficient; The compressor power setpoint (MW); Set the opening point (%) for the thermal storage regulating valve.

[0087] Peak-shaving demand forecasting model, i.e., power regulation demand forecasting model: .

[0088] This is the correction term for the residuals, representing the correction term of the autoregressive integral moving average model for the predicted residuals, which can improve the prediction accuracy.

[0089] The multi-objective optimization model is in each control cycle Solve the following constrained multi-objective optimization problem: .

[0090] Subject to .

[0091] .

[0092] .

[0093] in, To minimize the cumulative error during the adjustment process and ensure speed; To minimize operating costs, For system round-trip efficiency, , All are cost coefficients; The penalty function ensures the protection of critical safety parameters. (Temperature, pressure, flow rate) must not exceed the limits.

[0094] After optimization, the optimal prediction result can be generated. The corresponding curve's decision logic can be simplified into a function that combines rules and models: .

[0095] When the rate requirement in the AGC control command is high, the Carnot battery subsystem is used first; when long-term peak shaving is required, the dynamic transfer is determined by interpolation of the state of charge of the molten salt thermal storage subsystem, the required power and the expected duration.

[0096] In one exemplary embodiment, such as Figure 4 As shown, a peak-shaving operation device for a coal-fired power unit combining molten salt thermal storage and a Carnot battery is provided, comprising: The information data acquisition module is used to acquire information data, including: AGC control commands and real-time operating data of the coal-fired unit; the AGC control commands are control commands generated by the power grid dispatch center based on the real-time frequency of the power system and the power deviation of the tie line, based on the control system; the operating data includes: boiler load, main steam pressure, flow rate, and turbine speed.

[0097] The demand forecasting module is used to predict peak demand based on the information data according to the power regulation demand forecasting model, and obtain the forecasting results; the power regulation demand forecasting model is obtained by performing time series analysis on the long short-term memory network model using a multi-objective optimization model.

[0098] An energy scheduling strategy determination module is used to determine an energy scheduling strategy based on the prediction results; the energy scheduling strategy includes: thermal storage power coordination instructions and heat release power coordination instructions.

[0099] The operation adjustment module is used to adjust the operation of the coal-fired unit, the molten salt thermal storage subsystem, and the Carnot battery subsystem based on the energy dispatch strategy and the control system.

[0100] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 5 As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores peak-shaving operation data for coal-fired power units using combined molten salt thermal storage and Carnot batteries. The I / O interfaces are used for information exchange between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a peak-shaving operation method for coal-fired power units using combined molten salt thermal storage and Carnot batteries.

[0101] Those skilled in the art will understand that Figure 5The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0102] In one exemplary embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0103] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0104] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0105] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0106] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0107] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, data processing logic devices, etc., and are not limited to these.

[0108] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for peak load operation of a coal-fired power plant combined with molten salt heat storage and Carnot cell, characterized in that, The coal-fired unit peak shaving operation method combined with molten salt heat storage and Carnot cell is applied to a coal-fired unit coupled with a molten salt heat storage system; the coal-fired unit coupled with the molten salt heat storage system comprises a coal-fired unit, a molten salt heat storage subsystem, a Carnot cell subsystem, a coupling interface unit and a control system; the control system is connected with the molten salt heat storage subsystem, the Carnot cell subsystem and the coal-fired unit through the coupling interface unit; The coal-fired unit peak shaving operation method combined with molten salt heat storage and Carnot cell comprises: obtaining information data; the information data comprises AGC control instructions and real-time operation data of the coal-fired unit; the AGC control instructions are control instructions generated by a power grid dispatching center according to a real-time frequency of a power system and a tie-line power deviation, and are obtained based on a control system; the operation data comprises a boiler load, a main steam pressure, a flow and a turbine speed; performing peak shaving demand prediction according to the information data based on a power regulation demand prediction model to obtain a prediction result; the power regulation demand prediction model is obtained by performing time series analysis on a long short-term memory network model by using a multi-objective optimization model; determining an energy scheduling strategy based on the prediction result; the energy scheduling strategy comprises a heat storage power coordination instruction and a heat release power coordination instruction; performing operation regulation on the coal-fired unit, the molten salt heat storage subsystem and the Carnot cell subsystem based on the control system according to the energy scheduling strategy.

2. The coal-fired unit peak shaving operation method of combined molten salt thermal storage and Carnot battery according to claim 1, characterized in that, The corresponding mathematical expression of the power regulation demand prediction model is: ； in, For the future Forecasted power regulation demand at any given time; It is a long short-term memory network model; These are used to train weights to capture the nonlinear timing relationship between runtime data and AGC control commands; for The running vector corresponding to the running data at any given time; for The instruction vector corresponding to the AGC control instruction at any given time; for The feedforward vector at time step; This is a correction term for the residual.

3. The coal-fired unit peak shaving operation method of combined molten salt thermal storage and Carnot battery according to claim 1, characterized in that, The corresponding mathematical expression of the multi-objective optimization model is: ； ； ； ； wherein, is a dynamic power allocation coefficient; is a multi-objective optimization function vector; is a coordinated instruction of total heat storage / release power; is a minimum adjustment process cumulative error; is a control period; is a minimum operating cost; is a penalty function; is a safety parameter; 、 are cost coefficients; is a system round-trip efficiency; is is an actual output power of the coal-fired unit at the moment; is is an AGC target power instruction issued by the power grid dispatching center at the moment; is the electrical energy consumed by the compressor; is the electrical energy generated by the Rankine cycle expander; is the penalty weight coefficient of the safety parameter; is the maximum upper limit value allowed by the safety parameter; is a transpose.

4. The coal-fired unit peak shaving operation method of combined molten salt thermal storage and Carnot battery according to claim 1, characterized in that, The corresponding expression of the prediction result is: ； wherein, is the final determined power allocation ratio; is the maximum value of the power allocation coefficient; is the load change rate requirement of the AGC control instruction; is the predicted rate threshold value; is the interpolation function; is the state of charge of the molten salt thermal storage system; is the power regulation demand prediction value; is the predicted peak shaving duration.

5. The coal-fired unit peak shaving operation method of combined molten salt thermal storage and Carnot battery according to claim 1, characterized in that, The corresponding expression of the energy scheduling strategy is: ； wherein, is a power instruction vector corresponding to the energy scheduling strategy; is a total storage / heat release power coordination instruction; is a dynamic power distribution coefficient; is a compressor power setpoint; is a heat storage regulating valve opening setpoint; is a transpose.

6. The coal-fired unit peak-load operation method of combined molten-salt thermal storage and Carnot battery according to claim 1, characterized in that, Performing operation regulation on the coal-fired unit, the molten salt heat storage subsystem and the Carnot cell subsystem based on the control system according to the energy scheduling strategy, specifically comprising: when the energy scheduling strategy is the heat storage power coordination instruction, performing heat pump circulation and molten salt coupling heat storage and steam extraction molten salt coupling heat storage based on the control system; wherein the molten salt heat storage subsystem comprises a molten salt storage tank, a molten salt pump and a molten salt heat exchanger; the Carnot cell subsystem comprises a heat pump circulation unit and a Rankine cycle unit; the heat pump circulation unit comprises a compressor, an evaporator, a regenerator and a throttle valve; the Rankine cycle unit comprises an expander, a generator, a condenser and a circulating pump; the coupling interface unit comprises a heat storage regulating valve, a feedwater diversion valve, a sampling point interface, a grid connection interface and a molten salt distribution interface; wherein, in the heat pump circulation and molten salt coupling heat storage stage: controlling the sampling point interface included in the coal-fired unit to be in an open state based on the control system, so that a part of electric energy at the output end of the generator in the coal-fired unit is diverted to the compressor included in the heat pump circulation unit; Based on the control system according to the compressor inlet temperature And the compressor inlet pressure , the compressor pressure ratio is dynamically calculated , and the compressor driving argon working medium is controlled to exchange heat with the cold molten salt at 290 DEG C in the molten salt heat exchanger contained in the molten salt heat storage subsystem, with the set compressor outlet temperature and isentropic efficiency as the control target. adjusting the frequency of the molten salt pump included in the molten salt heat storage subsystem and controlling the cold molten salt flow based on the control system, to ensure that the cold molten salt is heated to a target temperature of 560 DEG C and then stored in the hot tank, and the argon working medium then flows through the regenerator and the throttle valve included in the heat pump circulation unit to be cooled and depressurized, so as to complete the circulation; in the steam extraction molten salt coupling heat storage stage: The control system controls the heat storage regulating valve in the coupling interface unit to be in an open state, and part of the main steam to the steam turbine is branched to the molten salt heat exchanger; at the same time of steam branching, the control system adjusts the feedwater branching valve in the coupling interface unit to branch part of the boiler feedwater to the same molten salt heat exchanger, the steam is condensed in the molten salt heat exchanger, and heat is transferred to the molten salt, and the condensed water returns to the condenser; When the energy scheduling strategy is a heat release power coordination instruction, the control system controls the coupling of Rankine cycle and molten salt heat release and the coupling of molten salt and feedwater heat release; In the coupling of Rankine cycle and molten salt heat release stage: The control system controls the Rankine cycle unit to start, and the 560 DEG C high-temperature molten salt in the hot tank is pumped to the evaporator in the heat pump cycle unit; based on the control system adjusting the opening of the regulating valve according to the evaporator inlet pressure and pressure ratio The adjusting valve before the expander contained in the Rankine cycle unit is adjusted, so that the working medium water absorbs heat in the evaporator to become steam, drives the expander to rotate, and drives the generator contained in the Rankine cycle unit to rotate, to generate electric energy; the generated electric energy is connected to the power grid through the grid-connected interface contained in the coupling interface unit, and the heat-released and cooled molten salt flows back to the cold tank. In the coupling of molten salt and feedwater heat release stage: The control system controls the feedwater branching valve in the coupling interface unit to be in an open state, so as to branch part of the feedwater below the set temperature to the molten salt heat exchanger in the molten salt heat storage subsystem, and the feedwater is heated by the molten salt above the set temperature, and becomes the feedwater above the set temperature, and then is combined with the main feedwater to enter the boiler.

7. A coal-fired unit peak shaving operation device combined with molten salt heat storage and Carnot cell, characterized in that, It comprises: An information data acquisition module is configured to acquire information data, wherein the information data comprises an AGC control instruction and real-time operation data of the coal-fired generating unit, the AGC control instruction is obtained by a control system and is generated by a power grid dispatching center according to a real-time frequency of a power system and a tie-line power deviation, and the operation data comprises a boiler load, a main steam pressure, a flow rate and a turbine speed; A demand prediction module is configured to perform peak regulation demand prediction based on a power regulation demand prediction model to obtain a prediction result, wherein the power regulation demand prediction model is obtained by performing time series analysis on a long short-term memory network model by using a multi-objective optimization model; An energy scheduling strategy determination module is configured to determine an energy scheduling strategy based on the prediction result, wherein the energy scheduling strategy comprises a heat storage power coordination instruction and a heat release power coordination instruction; An operation regulation module is configured to perform operation regulation on the coal-fired generating unit, the molten salt heat storage subsystem and the Carnot cell subsystem based on a control system according to the energy scheduling strategy.

8. A computer device comprising: A memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the coal-fired generating unit peak regulation operation method of combined molten salt heat storage and Carnot cell according to any one of claims 1-6.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the coal-fired generating unit peak regulation operation method of combined molten salt heat storage and Carnot cell according to any one of claims 1-6.

10. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the coal-fired generating unit peak regulation operation method of combined molten salt heat storage and Carnot cell according to any one of claims 1-6.

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