Waste heat recovery system for improving peak regulation capacity of thermal power generating unit

Abstract

The invention relates to the field of thermal power generating unit peak regulation and waste heat utilization, and discloses a waste heat recovery method and system for improving the thermal power generating unit peak regulation capacity. The method comprises the following steps: carrying out grade identification and cascade recovery on boiler exhaust smoke and steam turbine circulating water waste heat of the thermal power generating unit to respectively obtain high-grade heat energy and low-grade heat energy; the high-grade heat energy and the low-grade heat energy are gathered into a heat storage device to be stored and integrated, and unified and schedulable heat storage energy is formed; receiving a power grid regulation and control signal in real time through an intelligent control system, and synchronously monitoring an energy storage state parameter of the heat storage device and a real-time operation boundary parameter of the thermal power generating unit; comparing the power grid regulation and control signal with the energy storage state parameter and the operation boundary parameter, and generating a control instruction according to a preset threshold strategy; and according to the control instruction, the heat energy released by the heat storage device as required is fed back to the thermal power generating unit thermodynamic system. According to the system, efficient recovery of waste heat resources and intelligent response of power grid requirements are achieved, and the peak regulation capacity and operation economy of the thermal power generating unit are remarkably improved.

Description

Technical Field

[0001] This application relates to the field of peak shaving and waste heat utilization of thermal power units, and in particular to a waste heat recovery method and system for improving the peak shaving capacity of thermal power units. Background Technology

[0002] With the large-scale grid connection of new energy sources, the power system's demand for deep and rapid peak shaving from thermal power units is becoming increasingly urgent. However, thermal power units themselves are limited by minimum technical output and boiler combustion stability limits, resulting in bottlenecks in peak shaving capacity. Simultaneously, a large amount of boiler flue gas and turbine circulating water waste heat generated during unit operation are typically directly discharged, leading to energy waste. Existing waste heat recovery technologies mostly focus on the utilization of heat energy itself, failing to dynamically coordinate with grid peak shaving needs. The energy storage and release processes lack intelligent scheduling, making it impossible to effectively convert recovered heat energy into flexibly adjustable power generation capacity, thus limiting their value in improving unit operational flexibility. Therefore, there is an urgent need for a method and system that can intelligently couple grid signals and achieve synergistic improvement in waste heat recovery and peak shaving capacity. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a waste heat recovery method and system for enhancing the peak-shaving capacity of thermal power units. The method involves identifying and cascading the waste heat from boiler flue gas and turbine circulating water to obtain heat energy of different grades; this energy is then integrated and stored as a unified, dispatchable thermal energy storage system; an intelligent control system receives grid control signals in real time and, considering the energy storage status and unit operating boundaries, generates optimized control commands through a dynamic threshold strategy; finally, the heat energy released by the thermal storage device is safely and accurately fed back to the thermal system as needed. This invention achieves high-value utilization of waste heat resources and rapid response to grid peak-shaving commands, effectively overcoming the inherent peak-shaving bottleneck of the unit and improving operational economy and system flexibility.

[0004] In some embodiments of this application, a waste heat recovery method for improving the peak-shaving capacity of thermal power units is provided, characterized by comprising: The boiler flue gas and turbine circulating water waste heat of thermal power units are identified by grade and recovered in stages to obtain high-grade and low-grade heat energy respectively. The high- and low-grade thermal energy is collected into a thermal storage device for storage and integration, forming a unified and dispatchable thermal energy storage; The intelligent control system receives grid control signals in real time and simultaneously monitors the energy storage status parameters of the thermal storage device and the real-time operating boundary parameters of the thermal power unit. The power grid control signal is compared with the energy storage state parameters and operating boundary parameters, and control commands are generated based on a preset threshold strategy. According to the control command, the heat energy released by the heat storage device as needed is fed back to the thermal power unit's thermal system.

[0005] In some embodiments of this application, high-grade and low-grade thermal energy are obtained by identifying the grade of boiler flue gas and turbine circulating water waste heat from thermal power units and performing cascade recovery, including: Based on a preset temperature threshold, the boiler flue gas and turbine circulating water waste heat are graded and classified into high-grade waste heat and low-grade waste heat. The high-grade waste heat is introduced into the first recovery circuit for recovery to obtain the high-grade thermal energy. The low-grade waste heat is introduced into the second recovery circuit for recovery and heating to obtain the low-grade thermal energy.

[0006] In some embodiments of this application, the high- and low-grade thermal energy is collected into a thermal storage device for storage and integration, forming a unified and dispatchable thermal energy storage system, including: Set the target energy storage temperature range for the heat storage device; The mixing ratio of the high-grade thermal energy and the low-grade thermal energy is adjusted according to the target energy storage temperature range. The mixed thermal energy is stored in the heat storage device to form a thermal energy storage device with stable temperature and energy density.

[0007] In some embodiments of this application, an intelligent control system receives grid control signals in real time and simultaneously monitors the energy storage status parameters of the thermal storage device and the real-time operating boundary parameters of the thermal power unit, including: It receives control signals from the power system control entity in real time; The energy storage status parameters of the thermal storage device are monitored synchronously, including the temperature, pressure and thermal storage capacity of the thermal storage medium. The real-time operating boundary parameters of the thermal power unit are monitored synchronously. These operating boundary parameters include the unit's current output, minimum technical output, boiler load rate, and main steam parameters.

[0008] In some embodiments of this application, the power grid control signal is compared with the energy storage state parameters and operating boundary parameters, and control commands are generated according to a preset threshold strategy, including: The current peak-shaving demand mode of the thermal power unit is determined based on the power grid control signal. Set the corresponding control target priority and associated threshold set for the peak-shaving demand mode; The energy storage state parameters of the thermal storage device and the operating boundary parameters of the thermal power unit are compared with the threshold set to generate comparison results; Based on the comparison results and the control target priority, instructions for the heat storage device in different modes are generated.

[0009] In some embodiments of this application, a corresponding control target priority and associated threshold set are set for the peak-shaving demand mode, including: Pre-store a set of basic thresholds that match different peak-shaving demand patterns; Based on the time scale information carried in the power grid control signal, the key thresholds in the basic threshold set are dynamically offset and adjusted. Based on the real-time energy storage density of the heat storage device, the threshold related to the heat charging and discharging rate is compensated and corrected online.

[0010] In some embodiments of this application, instructions for the heat storage device in different modes are generated based on the comparison results and the control target priority, including: The comparison results are converted into quantified deviation values ​​of each control target constraint. Based on the priority of the control objectives, the quantified values ​​of each deviation are weighted and combined to generate system optimization indicators; The system optimization indicators are matched with preset command trigger thresholds to map out the specific operating mode commands and power commands of the thermal storage device.

[0011] Some embodiments of this application also include: The system model is invoked to predict the critical states of the generating units and energy storage within a future scheduling cycle based on the control commands. The predicted state is verified against the safe operating boundary, and its response performance to power grid control signals is evaluated. Based on the verification and evaluation results, the control commands can be executed by choosing to execute them directly, execute them after modification, or replace them with a backup security strategy.

[0012] In some embodiments of this application, according to the control command, the thermal energy released by the heat storage device as needed is fed back to the thermal power unit's thermal system, including: The control commands are analyzed to determine the target feedback path and release power; Based on the target feedback path, the valve is switched to direct the heat energy released by the heat storage device to a predetermined thermal system interface; Adjust the released heat energy flow rate to match the parameters at the interface of the thermal system.

[0013] In some embodiments of this application, a waste heat recovery system for improving the peak-shaving capacity of thermal power units includes: The waste heat recovery module is used to identify the grade and recover the waste heat from the boiler flue gas and turbine circulating water of the thermal power unit in stages, so as to obtain high-grade and low-grade heat energy respectively. The thermal energy storage and scheduling module is used to collect the high- and low-grade thermal energy into the thermal storage device for storage and integration, forming a unified and dispatchable thermal energy storage; The intelligent sensing and communication module is used to receive grid control signals in real time through the intelligent control system, and simultaneously monitor the energy storage status parameters of the thermal storage device and the real-time operating boundary parameters of the thermal power unit. The intelligent decision-making module is used to compare the power grid control signal with the energy storage state parameters and operating boundary parameters, and generate control commands based on a preset threshold strategy. The thermal energy feedback execution module is used to feed back the thermal energy released by the thermal storage device as needed to the thermal power unit's thermal system according to the control command.

[0014] The waste heat recovery method and system for improving the peak-shaving capacity of thermal power units according to embodiments of this application have the following advantages compared with the prior art: By identifying the quality and cascading the recovery of waste heat from boiler flue gas and circulating water, high-quality and efficient use of thermal energy and improved efficiency of low-quality energy are achieved, thereby enhancing the overall energy utilization efficiency. By integrating discrete waste heat resources into a unified and dispatchable thermal energy storage system and intelligently linking it with grid control signals, and generating optimized instructions based on real-time status and dynamic threshold strategies, the thermal storage device can accurately and on-demand feed back heat energy to the thermal system, effectively expanding the unit's load regulation range and response speed. This invention not only significantly enhances the deep peak-shaving and rapid frequency regulation capabilities of thermal power units but also creates additional economic benefits through waste heat recovery, achieving a synergy between increased flexibility and energy conservation. Attached Figure Description

[0015] Figure 1 This is a schematic flowchart of a waste heat recovery method for improving the peak-shaving capacity of thermal power units in an embodiment of this application. Detailed Implementation

[0016] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0017] like Figure 1 As shown in the figure, an embodiment of this application provides a waste heat recovery method for improving the peak-shaving capacity of thermal power units, comprising: The boiler flue gas and turbine circulating water waste heat of thermal power units are identified by grade and recovered in stages to obtain high-grade and low-grade heat energy respectively. The high- and low-grade thermal energy is collected into a thermal storage device for storage and integration, forming a unified and dispatchable thermal energy storage; The intelligent control system receives grid control signals in real time and simultaneously monitors the energy storage status parameters of the thermal storage device and the real-time operating boundary parameters of the thermal power unit. The power grid control signal is compared with the energy storage state parameters and operating boundary parameters, and control commands are generated based on a preset threshold strategy. According to the control command, the heat energy released by the heat storage device as needed is fed back to the thermal power unit's thermal system.

[0018] In this embodiment, the power grid control signals include power grid dispatching instructions and electricity price signals.

[0019] In some embodiments of this application, high-grade and low-grade thermal energy are obtained by identifying the grade of boiler flue gas and turbine circulating water waste heat from thermal power units and performing cascade recovery, including: Based on a preset temperature threshold, the boiler flue gas and turbine circulating water waste heat are graded and classified into high-grade waste heat and low-grade waste heat. The high-grade waste heat is introduced into the first recovery circuit for recovery to obtain the high-grade thermal energy. The low-grade waste heat is introduced into the second recovery circuit for recovery and heating to obtain the low-grade thermal energy.

[0020] In this embodiment, the system automatically identifies and classifies the energy grade of the two major waste heat sources of the thermal power unit: boiler flue gas and turbine circulating water, based on preset temperature thresholds. The temperature thresholds are key parameters set comprehensively based on thermodynamic analysis, unit operating characteristics, and technical and economic considerations, used to clearly distinguish between high-grade and low-grade waste heat. Boiler flue gas, due to its higher temperature, is identified as high-grade waste heat, containing a high amount of usable energy; while turbine circulating water waste heat, due to its lower temperature, is identified as low-grade waste heat, characterized by a large total heat volume but higher difficulty in utilization.

[0021] In this embodiment, the system guides the sorted waste heat through different recovery paths to achieve tiered utilization. For high-grade waste heat, the system guides it into the first recovery loop. The core equipment of this loop is a flue gas heat exchanger, which, through efficient heat exchange, can directly and efficiently recover the heat from the exhaust gas to produce high-temperature hot water or low-pressure steam, i.e., the high-grade thermal energy. This process aims to maximize the work-capacity of high-grade heat.

[0022] In this embodiment, the low-grade waste heat is introduced into a second recovery loop. The core equipment of this loop is a heat pump system, equipped with a corresponding low-temperature heat exchanger to collect heat from the circulating water. The heat pump system consumes a small amount of high-grade heat source or electricity as a driving force to raise the temperature of the collected low-grade waste heat to an economically viable level, thereby producing the low-grade thermal energy. Essentially, this process upgrades the low-temperature heat that is difficult to use directly, making it valuable for heating the low-pressure section of the unit or for external heat supply.

[0023] In this embodiment, the differentiated recovery strategy based on grade identification achieves high-quality high-use and low-quality waste heat recovery from thermal power units, laying an efficient and reasonable foundation for subsequent energy storage and scheduling.

[0024] In some embodiments of this application, the high- and low-grade thermal energy is collected into a thermal storage device for storage and integration, forming a unified and dispatchable thermal energy storage system, including: Set the target energy storage temperature range for the heat storage device; The mixing ratio of the high-grade thermal energy and the low-grade thermal energy is adjusted according to the target energy storage temperature range. The mixed thermal energy is stored in the heat storage device to form a thermal energy storage device with stable temperature and energy density.

[0025] In this embodiment, the system sets a target energy storage temperature range based on the requirements of the thermal power unit's thermal system and the technical characteristics of the heat storage device itself. This range is an optimized temperature interval; its lower limit must ensure that the stored heat energy can meet the minimum temperature requirements of processes such as boiler feedwater heating when released, while the upper limit is limited by the safe operating temperature of the heat storage medium and the pressure-bearing design of the equipment. The purpose of setting this range is to provide a unified quality standard for the subsequent integration of heat energy of different grades.

[0026] In this embodiment, the system enters a dynamic integration and adjustment phase. The temperature and flow rate of high-grade and low-grade thermal energy before it enters the thermal storage device are monitored in real time. Based on the target energy storage temperature range, the mixing ratio of high-grade and low-grade thermal energy is dynamically adjusted through actuators such as regulating valves. When the temperature of the low-grade thermal energy is too low, the system automatically increases the proportion of high-temperature heat flow or decreases the flow rate of low-temperature heat flow, so that the total temperature of the mixed heat medium is precisely controlled and stabilized within the target range. This process achieves smoothing and standardization of fluctuating input thermal energy.

[0027] In this embodiment, after the proportional adjustment is completed, the uniformly mixed and temperature-compliant thermal energy is transferred to the thermal storage medium within the thermal storage device via a heat exchanger and stored. The core function of the thermal storage device is to realize the translation of energy over time, transforming immediate and potentially fluctuating waste heat resources into strategic reserves that can be stored long-term and readily available. Through the series of steps described above—setting targets, dynamic mixing, and efficient storage—a stable thermal energy storage with stable temperature and energy density is ultimately formed within the thermal storage device. This means that the stored thermal energy not only has a uniform temperature and minimal fluctuations overall, but also that the heat contained in a unit volume of the energy storage medium remains at a high and stable level. This state makes thermal energy storage a high-quality, standardized energy commodity with clearly defined parameters that can be accurately measured and predicted, thus laying a solid physical foundation for subsequent response to grid commands and achieving precise power regulation at the millisecond to hour level.

[0028] In some embodiments of this application, an intelligent control system receives grid control signals in real time and simultaneously monitors the energy storage status parameters of the thermal storage device and the real-time operating boundary parameters of the thermal power unit, including: It receives control signals from the power system control entity in real time; The energy storage status parameters of the thermal storage device are monitored synchronously, including the temperature, pressure and thermal storage capacity of the thermal storage medium. The real-time operating boundary parameters of the thermal power unit are monitored synchronously. These operating boundary parameters include the unit's current output, minimum technical output, boiler load rate, and main steam parameters.

[0029] In this embodiment, the main entities controlling the power system include the power grid dispatching agency and the electricity market.

[0030] In this embodiment, the intelligent control system receives control signals from the power system's control entities in real time via a dedicated data communication gateway. These control entities primarily include two types of entities: first, the power grid dispatching agency, representing the safe operation of the power grid, whose instructions, such as Automatic Generation Control (AGC) instructions and peak-shaving capacity call instructions, are direct control commands that the system must respond to with priority; second, the electricity market, representing the economic operation of the power grid, whose published signals, such as nodal prices, time-of-use prices, or ancillary service clearing prices, provide the system with a basis for decision-making regarding participation in peak shaving in an economically optimal manner. Receiving and accurately interpreting these signals is the information input port for this system to coordinate and interact with the power grid, maximizing its value.

[0031] In this embodiment, the system comprehensively senses the internal state. It continuously monitors the energy storage status parameters of the heat storage device through a sensor array deployed on the heat storage device body and pipelines. These include: (1) the temperature of the heat storage medium, used to assess the quality of the stored thermal energy; (2) the pressure inside the device, especially for pressurized heat storage equipment, which is crucial for monitoring safe operation; and (3) the heat storage capacity, i.e., the total amount of usable thermal energy calculated in real time based on the temperature field and the thermal properties of the medium.

[0032] In this embodiment, the system synchronously monitors the real-time operating boundary parameters of the thermal power unit. Synchronization means that this monitoring action is highly consistent with the timing of receiving external signals and collecting energy storage status, ensuring the integrity and immediacy of the decision-making basis. These boundary parameters are obtained in real-time from the original distributed control system of the thermal power unit through a standard data interface, mainly including: the unit's current output (real-time power generation), the minimum technical output (the lowest load at which the unit can operate safely and stably, which is the hard lower limit for deep peak shaving), boiler load rate, and key steam parameters. Monitoring these parameters aims to ensure that any operational decisions made in response to grid peak shaving are strictly based within the current safe operating margin of the main equipment, achieving a dynamic balance between external demand and internal constraints. Through the synchronous collection and integration of these three types of information—external commands, internal energy storage status, and main equipment operating boundaries—the intelligent control system constructs a complete, real-time, and accurate decision information pool, providing a reliable data foundation for subsequent execution of complex multi-objective optimization and safety verification algorithms.

[0033] In some embodiments of this application, the power grid control signal is compared with the energy storage state parameters and operating boundary parameters, and control commands are generated according to a preset threshold strategy, including: The current peak-shaving demand mode of the thermal power unit is determined based on the power grid control signal. Set the corresponding control target priority and associated threshold set for the peak-shaving demand mode; The energy storage state parameters of the thermal storage device and the operating boundary parameters of the thermal power unit are compared with the threshold set to generate comparison results; Based on the comparison results and the control target priority, instructions for the heat storage device in different modes are generated.

[0034] In this embodiment, the peak demand mode refers to the different operating objectives and strategies defined for thermal power units based on the nature and urgency of the grid control signals. These include: (1) Deep peak shaving mode: responding to long-term load differences in the grid, with the goal of minimizing unit output, and the control objective is to maximize the storage of thermal energy; (2) Fast frequency regulation mode: responding to second-level or minute-level frequency fluctuations in the grid, with the goal of fast and accurate power compensation, and the control objective is to ensure that the energy storage has the ability to charge and discharge quickly; (3) Economic operation mode: mainly responding to time-of-use electricity price signals, releasing thermal energy to generate more electricity during peak electricity price periods to generate profits, and storing thermal energy during off-peak periods, and the control objective is to maximize profits.

[0035] In some embodiments of this application, a corresponding control target priority and associated threshold set are set for the peak-shaving demand mode, including: Pre-store a set of basic thresholds that match different peak-shaving demand patterns; Based on the time scale information carried in the power grid control signal, the key thresholds in the basic threshold set are dynamically offset and adjusted. Based on the real-time energy storage density of the heat storage device, the threshold related to the heat charging and discharging rate is compensated and corrected online.

[0036] In this embodiment, the intelligent control system analyzes the received grid regulation signals to determine the current peak-shaving demand mode of the thermal power unit. This mode defines the core task of the system in the current time period, which may be a deep peak-shaving mode aimed at maximizing load reduction, a fast frequency regulation mode aimed at rapidly and accurately compensating for power, or an economical operation mode aimed at maximizing revenue by chasing electricity price differences. Different modes correspond to different control objectives and priorities.

[0037] In this embodiment, for the identified peak-shaving demand pattern, the system calls the corresponding set of basic thresholds. This set is a set of core parameter boundaries that are statically configured in advance based on equipment safety limits, design parameters, and historical optimized operating data, including the upper and lower safety limits of thermal storage temperature, the extreme values ​​of charging and discharging power, and the safe range of host load rate, etc.

[0038] In this embodiment, the system's decision-making process does not rigidly apply basic thresholds. The system further analyzes the time-scale information contained in the power grid signal, such as the response time of commands and the duration of peak electricity prices. Based on this information, the system dynamically adjusts the key thresholds in the basic threshold set. For example, when faced with a frequency regulation command requiring a rapid response, the system temporarily and strategically relaxes the upper limit of the heat release rate constraint to prioritize ensuring response speed.

[0039] In this embodiment, the decision-making process is also closely coupled with the real-time state of the system. The system continuously calculates the real-time energy storage density of the thermal storage device, i.e., the thermal energy contained in a unit volume of thermal storage medium. Based on this density value, the system performs online compensation and correction on thresholds related to the charging and releasing rates. Specifically, when the real-time energy storage density is too high, to prevent the equipment's thermal stress from exceeding limits, the system automatically and in real-time lowers the maximum allowable charging rate threshold; conversely, when the energy storage density is low, the charging rate can be appropriately increased to accelerate thermal storage. This correction ensures that all operations are performed within the optimal and safe range allowed by the real-time physical state of the equipment.

[0040] In some embodiments of this application, instructions for the heat storage device in different modes are generated based on the comparison results and the control target priority, including: The comparison results are converted into quantified deviation values ​​of each control target constraint. Based on the priority of the control objectives, the quantified values ​​of each deviation are weighted and combined to generate system optimization indicators; The system optimization indicators are matched with preset command trigger thresholds to map out the specific operating mode commands and power commands of the thermal storage device.

[0041] In this embodiment, the system processes the generated comparison results and converts them into quantified deviations from the constraints of each control objective. That is, the satisfaction of each safety, economic, or performance constraint, such as "temperature must not exceed the limit", "output must not be lower than the lower limit", and "response time should be shorter than required", is calculated into a specific, comparable value, such as temperature difference, power margin, time difference, etc., thereby describing the complex system state as a set of standardized data.

[0042] In this embodiment, the system performs a weighted aggregation of these deviation quantifications based on the preset control target priorities for the current peak-shaving demand mode. Control targets with higher priorities are assigned a larger weight coefficient for their corresponding deviations in the aggregation calculation. For example, in the fast frequency regulation mode, the deviation of response delay is given a very high weight; while in the economic mode, the deviation of expected revenue has the largest weight. Through weighted summation or a similar fusion algorithm, all deviations are integrated into a single value that reflects the overall optimization needs of the system, namely the system optimization index. The magnitude of this index characterizes the overall deviation degree, and its positive or negative sign indicates the overall adjustment direction: positive indicates the need for heat release, and negative indicates the need for heat storage.

[0043] In this embodiment, the system matches optimization metrics with a set of preset instruction trigger thresholds. These thresholds divide continuous metric values ​​into several discrete decision intervals, each interval corresponding to a preset operating strategy. When the metric exceeds a certain positive threshold, it means that the system urgently needs to release a large amount of heat energy, thus matching a rapid heat release mode; when the metric is in an intermediate interval, a stable heat release mode may be matched; when the metric is below a certain negative threshold, a heat storage mode is matched.

[0044] In this embodiment, based on the matching results, the system maps and generates specific operating mode instructions and power instructions for the thermal storage device. The specific operating mode instructions specify the working state that the device should enter, while the power instructions calculate and assign a precise power value based on the absolute value of the optimization indicators, the real-time energy storage capacity, and the unit's receiving capacity.

[0045] Some embodiments of this application also include: The system model is invoked to predict the critical states of the generating units and energy storage within a future scheduling cycle based on the control commands. The predicted state is verified against the safe operating boundary, and its response performance to power grid control signals is evaluated. Based on the verification and evaluation results, the control commands can be executed by choosing to execute them directly, execute them after modification, or replace them with a backup security strategy.

[0046] In this embodiment, a built-in system model is invoked to predict the key states of the unit and energy storage within a future scheduling cycle based on the control commands. This model integrates the dynamic characteristics of the boiler, turbine, thermal storage device, and thermal loop. Using the current real-time state as initial conditions and the control commands as input, the system performs advanced simulation calculations to obtain predicted change curves for key parameters such as unit power generation, main steam parameters, and thermal storage device temperature and capacity over a future period.

[0047] In this embodiment, based on the predicted state trajectory, the system further evaluates its response performance to grid control signals. Specifically, it compares the predicted unit output curve with the load command or frequency regulation demand issued by the grid, and calculates quantitative performance indicators such as actual response time, regulation rate, steady-state error, and command completion rate through algorithms.

[0048] In this embodiment, the system intelligently selects the final execution strategy based on the verification and evaluation results. This is a decision node containing three paths: Direct execution: If the predicted state is within the safety boundary throughout and the performance evaluation shows that the grid task can be completed excellently, the system directly issues the original instruction to the actuator. Execution after correction: If the prediction indicates a slight overshoot or slightly insufficient response performance, but can be improved through adjustment, the system automatically optimizes and corrects the power or time parameters of the original instruction online, generating a safer or more feasible corrected instruction before execution. Replacement with backup safety strategy: If the prediction clearly shows that executing the original instruction will cause serious safety exceedances, such as causing unit over-temperature and over-pressure, energy storage medium solidification or vaporization, the system immediately rejects the original instruction and automatically switches to a preset, absolutely conservative backup safety strategy, such as forcing the system into a heat preservation standby state or operating only at the minimum safe power.

[0049] In some embodiments of this application, according to the control command, the thermal energy released by the heat storage device as needed is fed back to the thermal power unit's thermal system, including: The control commands are analyzed to determine the target feedback path and release power; Based on the target feedback path, the valve is switched to direct the heat energy released by the heat storage device to a predetermined thermal system interface; Adjust the released heat energy flow rate to match the parameters at the interface of the thermal system.

[0050] In this embodiment, control commands from the intelligent decision-making system are parsed to determine the target feedback path and the released power. The target feedback path is selected from multiple pre-designed integrated schemes, such as directing heat energy to the inlet of the boiler's low-pressure economizer to increase the feedwater temperature, directing it to the air heater to replace part of the extracted steam, or directing it to the first station of the heating network to increase the heating capacity.

[0051] In this embodiment, the system controls the switching of the states of a series of valves in the pipeline according to the target feedback path. By opening the valves on the target branch and strictly closing the valves on other branches, it ensures that the high-temperature heat medium flowing from the heat storage device is accurately guided to the selected, predetermined thermal system interface. These predetermined thermal system interfaces are standardized access points reserved during the design or modification of the power plant's thermal system, ensuring the standardization and safety of the integration.

[0052] In this embodiment, after the heat energy is guided to the target interface, the system enters a dynamic fusion control phase, adjusting the released heat energy flow rate to match the parameters at the thermal system interface. The system monitors key parameters of the main system at the interface in real time and dynamically and precisely adjusts the opening of the regulating valve on the release pipeline through a control algorithm. The purpose is to control the temperature and flow rate of the external heat supply, ensuring its smooth and stable integration into the main system, avoiding any impact on the main unit's operation due to temperature differences or sudden flow changes, thereby achieving safe, efficient, and seamless heat energy feedback.

[0053] In this embodiment, by analyzing the series of automated execution steps of route selection, valve switching, and precise fusion, this application ensures that the optimization instructions generated by intelligent decision-making can be accurately, smoothly, and safely transformed into actual actions of the physical system, and ultimately the stored waste heat is precisely transformed into effective power to improve the unit's power generation output.

[0054] In some embodiments of this application, a waste heat recovery system for improving the peak-shaving capacity of thermal power units includes: The waste heat recovery module is used to identify the grade and recover the waste heat from the boiler flue gas and turbine circulating water of the thermal power unit in stages, so as to obtain high-grade and low-grade heat energy respectively. The thermal energy storage and scheduling module is used to collect the high- and low-grade thermal energy into the thermal storage device for storage and integration, forming a unified and dispatchable thermal energy storage; The intelligent sensing and communication module is used to receive grid control signals in real time through the intelligent control system, and simultaneously monitor the energy storage status parameters of the thermal storage device and the real-time operating boundary parameters of the thermal power unit. The intelligent decision-making module is used to compare the power grid control signal with the energy storage state parameters and operating boundary parameters, and generate control commands based on a preset threshold strategy. The thermal energy feedback execution module is used to feed back the thermal energy released by the thermal storage device as needed to the thermal power unit's thermal system according to the control command.

[0055] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application.

Claims

1. A waste heat recovery method for improving the peak-shaving capacity of thermal power units, characterized in that, include: The boiler flue gas and turbine circulating water waste heat of thermal power units are identified by grade and recovered in stages to obtain high-grade and low-grade heat energy respectively. The high- and low-grade thermal energy is collected into a thermal storage device for storage and integration, forming a unified and dispatchable thermal energy storage; The intelligent control system receives grid control signals in real time and simultaneously monitors the energy storage status parameters of the thermal storage device and the real-time operating boundary parameters of the thermal power unit. The power grid control signal is compared with the energy storage state parameters and operating boundary parameters, and control commands are generated based on a preset threshold strategy. According to the control command, the heat energy released by the heat storage device as needed is fed back to the thermal power unit's thermal system.

2. The waste heat recovery method for improving the peak-shaving capacity of thermal power units as described in claim 1, characterized in that, Based on the grade identification and cascade recovery of waste heat from boiler flue gas and turbine circulating water in thermal power units, high-grade and low-grade heat energy are obtained separately, including: Based on a preset temperature threshold, the boiler flue gas and turbine circulating water waste heat are graded and classified into high-grade waste heat and low-grade waste heat. The high-grade waste heat is introduced into the first recovery circuit for recovery to obtain the high-grade thermal energy. The low-grade waste heat is introduced into the second recovery circuit for recovery and heating to obtain the low-grade thermal energy.

3. The waste heat recovery method for improving the peak-shaving capacity of thermal power units as described in claim 2, characterized in that, The high- and low-grade thermal energy is collected and stored in a thermal storage device to form a unified and dispatchable thermal energy storage system, including: Set the target energy storage temperature range for the heat storage device; The mixing ratio of the high-grade thermal energy and the low-grade thermal energy is adjusted according to the target energy storage temperature range. The mixed thermal energy is stored in the heat storage device to form a thermal energy storage device with stable temperature and energy density.

4. The waste heat recovery method for improving the peak-shaving capacity of thermal power units as described in claim 3, characterized in that, The intelligent control system receives grid control signals in real time and simultaneously monitors the energy storage status parameters of the thermal storage device and the real-time operating boundary parameters of the thermal power unit, including: It receives control signals from the power system control entity in real time; The energy storage status parameters of the thermal storage device are monitored synchronously, including the temperature, pressure and thermal storage capacity of the thermal storage medium. The real-time operating boundary parameters of the thermal power unit are monitored synchronously. These operating boundary parameters include the unit's current output, minimum technical output, boiler load rate, and main steam parameters.

5. The waste heat recovery method for improving the peak-shaving capacity of thermal power units as described in claim 4, characterized in that, The grid control signal is compared with the energy storage state parameters and operating boundary parameters, and control commands are generated according to a preset threshold strategy, including: The current peak-shaving demand mode of the thermal power unit is determined based on the power grid control signal. Set the corresponding control target priority and associated threshold set for the peak-shaving demand mode; The energy storage state parameters of the thermal storage device and the operating boundary parameters of the thermal power unit are compared with the threshold set to generate comparison results; Based on the comparison results and the control target priority, instructions for the heat storage device in different modes are generated.

6. The waste heat recovery method for improving the peak-shaving capacity of thermal power units as described in claim 5, characterized in that, To define the corresponding control target priority and associated threshold set for the peak-shaving demand mode, including: Pre-store a set of basic thresholds that match different peak-shaving demand patterns; Based on the time scale information carried in the power grid control signal, the key thresholds in the basic threshold set are dynamically offset and adjusted. Based on the real-time energy storage density of the heat storage device, the threshold related to the heat charging and discharging rate is compensated and corrected online.

7. The waste heat recovery method for improving the peak-shaving capacity of thermal power units as described in claim 6, characterized in that, Based on the comparison results and the control target priority, instructions for the thermal storage device in different modes are generated, including: The comparison results are converted into quantified deviation values ​​of each control target constraint. Based on the priority of the control objectives, the quantified values ​​of each deviation are weighted and combined to generate system optimization indicators; The system optimization indicators are matched with preset command trigger thresholds to map out the specific operating mode commands and power commands of the thermal storage device.

8. The waste heat recovery method for improving the peak-shaving capacity of thermal power units as described in claim 5, characterized in that, Also includes: The system model is invoked to predict the critical states of the generating units and energy storage within a future scheduling cycle based on the control commands. The predicted state is verified against the safe operating boundary, and its response performance to power grid control signals is evaluated. Based on the verification and evaluation results, the control commands can be executed by choosing to execute them directly, execute them after modification, or replace them with a backup security strategy.

9. The waste heat recovery method for improving the peak-shaving capacity of thermal power units as described in claim 5, characterized in that, According to the control command, the thermal energy released by the heat storage device as needed is fed back to the thermal power unit's thermal system, including: The control commands are analyzed to determine the target feedback path and release power; Based on the target feedback path, the valve is switched to direct the heat energy released by the heat storage device to a predetermined thermal system interface; Adjust the released heat energy flow rate to match the parameters at the interface of the thermal system.

10. A waste heat recovery system for improving the peak-shaving capacity of thermal power units, characterized in that, include: The waste heat recovery module is used to identify the grade and recover the waste heat from the boiler flue gas and turbine circulating water of the thermal power unit in stages, so as to obtain high-grade and low-grade heat energy respectively. The thermal energy storage and scheduling module is used to collect the high- and low-grade thermal energy into the thermal storage device for storage and integration, forming a unified and dispatchable thermal energy storage; The intelligent sensing and communication module is used to receive grid control signals in real time through the intelligent control system, and simultaneously monitor the energy storage status parameters of the thermal storage device and the real-time operating boundary parameters of the thermal power unit. The intelligent decision-making module is used to compare the power grid control signal with the energy storage state parameters and operating boundary parameters, and generate control commands based on a preset threshold strategy. The thermal energy feedback execution module is used to feed back the thermal energy released by the thermal storage device as needed to the thermal power unit's thermal system according to the control command.

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