Load control method and device for coal-fired unit

Abstract

The invention discloses a load control method and device for a coal-fired unit, and relates to the technical field of coal-fired unit control. The method comprises the steps that when it is detected that a difference value exists between a load instruction of an automatic power generation controller and the actual load of a current unit, the difference value is calculated to serve as a load instruction difference value, and whether the fused salt heat storage system participates in coordinated variable load control or not is determined; if it is determined that the fused salt heat storage system participates in coordinated variable load control, the operation mode of the fused salt heat storage system is judged based on the operation state of a cold salt pump and the operation state of a hot salt pump in the fused salt heat storage system; a main steam extraction valve and a reheating steam extraction valve are controlled according to the operation mode of the fused salt heat storage system, so that the variable load rate is increased; the main steam extraction valve is arranged between a boiler of the coal-fired unit and a high-pressure cylinder of the coal-fired unit; and the reheating steam extraction valve is arranged between a high-pressure cylinder of the coal-fired unit and a medium-pressure cylinder of the coal-fired unit. The method is used for realizing the load control function of the coal-fired unit.

Description

Technical Field

[0001] This application relates to the technical field of coal-fired unit control, and particularly to a load control method and device for a coal-fired unit. Background Art

[0002] With the rapid development of new energy, the proportion of renewable energy sources with time-varying characteristics such as photovoltaic and wind power in the power grid has been increasing year by year, posing a huge challenge to the stable operation of the power grid. Due to its large thermal inertia and equipment safety limitations, the traditional coal-fired unit has a low load change rate and is difficult to meet the flexible peak shaving requirements for complementary operation with new energy.

[0003] Currently, existing coal-fired units are configured in a way that is thermally coupled with a molten salt energy storage system. In this configuration, when load control of the coal-fired unit is required, it is generally necessary to adjust and control multiple facilities in the molten salt energy storage system. However, in practical applications, although the existing load control method can solve the load control problem of coal-fired units to a certain extent, since its control process requires controlling and correlating the operating conditions of multiple settings in the molten salt energy storage system, the load control process is still relatively complex. Especially when a rapid adjustment of load change is needed, the existing load control method often fails to quickly respond to load changes due to the slow operating response of each device. Therefore, there is an urgent need for a load control method that can effectively improve the load change rate of coal-fired units. Summary of the Invention

[0004] Embodiments of this application provide a load control method and device for a coal-fired unit, with the main purpose of implementing a load control method for a coal-fired unit to solve the problems of complex load control process and slow load change response speed of existing coal-fired units.

[0005] To solve the above technical problems, the embodiments of this application provide the following technical solutions:

[0006] In a first aspect, this application provides a load control method for a coal-fired unit, which is applied to a load control device. The load control device is arranged between the coal-fired unit and the molten salt energy storage system, and there is a thermal energy function coupling between the coal-fired unit and the molten salt energy storage system. The method includes:

[0007] When a difference is detected between the load command of the automatic generation control device and the actual load of the current unit, calculate the difference as the load command difference, and determine whether the molten salt energy storage system participates in coordinated load change control;

[0008] If it is determined that the molten salt energy storage system participates in coordinated load change control, then judge the operation mode of the molten salt energy storage system based on the operation states of the cold salt pump and the hot salt pump in the molten salt energy storage system;

[0009] Control the main steam extraction valve and the reheat extraction valve according to the operating mode of the molten salt thermal energy storage system to improve the load change rate; wherein, the operating mode of the molten salt thermal energy storage system includes a thermal energy storage mode and a heat release mode; wherein, the main steam extraction valve is arranged between the boiler of the coal-fired unit and the high-pressure cylinder of the coal-fired unit and is used to extract steam into the molten salt thermal energy storage system; the reheat extraction valve is arranged between the high-pressure cylinder of the coal-fired unit and the intermediate-pressure cylinder of the coal-fired unit and is used to extract steam into the molten salt thermal energy storage system.

[0010] In a second aspect, the present application further provides a load control device for a coal-fired unit, which is applied to a load control device, and the load control device is arranged between the coal-fired unit and the molten salt thermal energy storage system, and there is a thermal energy function coupling between the coal-fired unit and the molten salt thermal energy storage system. The device includes:

[0011] A determination unit, configured to calculate the difference as a load command difference when detecting a difference between the load command of the automatic generation controller and the actual load of the current unit, and determine whether the molten salt thermal energy storage system participates in coordinated load change control;

[0012] A judgment unit, configured to judge the operating mode of the molten salt thermal energy storage system based on the operating states of the cold salt pump and the hot salt pump in the molten salt thermal energy storage system if it is determined that the molten salt thermal energy storage system participates in coordinated load change control;

[0013] A first control unit, configured to control the main steam extraction valve and the reheat extraction valve according to the operating mode of the molten salt thermal energy storage system to improve the load change rate; wherein, the operating mode of the molten salt thermal energy storage system includes a thermal energy storage mode and a heat release mode; wherein, the main steam extraction valve is arranged between the boiler of the coal-fired unit and the high-pressure cylinder of the coal-fired unit and is used to extract steam into the molten salt thermal energy storage system; the reheat extraction valve is arranged between the high-pressure cylinder of the coal-fired unit and the intermediate-pressure cylinder of the coal-fired unit and is used to extract steam into the molten salt thermal energy storage system.

[0014] In a third aspect, the present application further provides a storage medium, and the storage medium includes a stored program. When the program runs, it controls the device where the storage medium is located to execute the load control method for the coal-fired unit described in the first aspect.

[0015] In a fourth aspect, the present application further provides a load control device for a coal-fired unit. The device includes a storage medium; and one or more processors. The storage medium is coupled to the processor, and the processor is configured to execute program instructions stored in the storage medium; when the program instructions run, they execute the load control method for the coal-fired unit described in any one of the first aspect.

[0016] By means of the above technical solutions, the technical solutions provided by the present application have at least the following advantages:

[0017] The present application provides a load control method and device for a coal-fired unit, which are applied to a load control device. The load control device is arranged between the coal-fired unit and the molten salt thermal energy storage system. There is a thermal energy function coupling between the coal-fired unit and the molten salt thermal energy storage system. In the present application, when it is first detected that there is a difference between the load command of the automatic generation control device and the actual load of the current unit, the difference is calculated as the load command difference, and it is determined whether the molten salt thermal energy storage system participates in coordinated load change control; then, if it is determined that the molten salt thermal energy storage system participates in coordinated load change control, the operation mode of the molten salt thermal energy storage system is judged based on the operation states of the cold salt pump and the hot salt pump in the molten salt thermal energy storage system; finally, the main steam extraction valve and the reheater extraction valve are controlled according to the operation mode of the molten salt thermal energy storage system to improve the load change rate; wherein, the operation mode of the molten salt thermal energy storage system includes a heat storage mode and a heat release mode; wherein, the main steam extraction valve is arranged between the boiler of the coal-fired unit and the high-pressure cylinder of the coal-fired unit and is used to extract steam into the molten salt thermal energy storage system; the reheater extraction valve is arranged between the high-pressure cylinder and the intermediate-pressure cylinder of the coal-fired unit and is used to extract steam into the molten salt thermal energy storage system, so as to realize the load control function of the coal-fired unit. Compared with the prior art, in the load control process of the coal-fired unit in the present application, by monitoring the difference between the load command and the actual load of the current unit in real time, it is judged whether the molten salt thermal energy storage system needs to participate. Once it is determined that participation is required, the load control device will precisely control the relevant valves according to the operation mode (heat storage or heat release) of the molten salt thermal energy storage system. This control process can directly and precisely control the valves in the coal-fired unit and its coupled molten salt thermal energy storage system, without the need to control other facilities in the molten salt thermal energy storage system and the coal-fired unit. Compared with setting through other operating facilities, directly controlling the valves in the control loop can directly and quickly respond to load changes, optimize the operation of the molten salt system, and does not need to wait for the time required for the operation adjustment of each facility in the molten salt thermal energy storage system and the coal-fired unit, so that the load change rate of the coal-fired unit can be significantly improved, and the problems of low load change rate and slow response in the prior art can be solved. In addition, by precisely controlling the main steam extraction valve and the reheater extraction valve, the present application realizes the precise control of the valves in the system loop, omits the control process of other facilities in the loop, and simplifies the load control process. In addition, based on the method of the present application, the control is directly based on the valves, without the need to adjust the operation conditions of the facilities in the system, so that the frequent start-stop and large-scale adjustment processes of the corresponding equipment in the coal-fired unit and its molten salt thermal energy storage system are reduced during the process of stable load change, the equipment wear is reduced, and the service life of the equipment in the coal-fired unit and its coupled molten salt thermal energy storage system is prolonged.

[0018] The above description is only an overview of the technical solution of this application. In order to understand the technical means of this application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the following specific embodiments of this application are specifically given. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] By reading the following detailed description with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of this application will become easy to understand. In the drawings, several embodiments of this application are shown in an exemplary rather than restrictive manner, and the same or corresponding reference numerals represent the same or corresponding parts, where:

[0020] Figure 1 A flowchart of a load control method for a coal-fired unit provided by an embodiment of this application is shown;

[0021] Figure 2 A relationship diagram between the valve opening and the difference between the load command during the execution of another load control method for a coal-fired unit provided by an embodiment of this application is shown;

[0022] Figure 3 A schematic diagram of an actual application scenario of a load control method for a coal-fired unit provided by an embodiment of this application is shown;

[0023] Figure 4 A block diagram of the composition of a load control device for a coal-fired unit provided by an embodiment of this application is shown;

[0024] Figure 5 A block diagram of the composition of another load control device for a coal-fired unit provided by an embodiment of this application is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The exemplary embodiments of this application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that this application can be more thoroughly understood and the scope of this application can be fully conveyed to those skilled in the art.

[0026] It should be noted that unless otherwise specified, the technical terms or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art to which this application belongs.

[0027] An embodiment of this application provides a flowchart of a load control method for a coal-fired unit, as Figure 1 shown, the method includes:

[0028] 101. When a difference is detected between the load command of the automatic generation controller and the current actual load of the unit, calculate the difference as the load command difference, and determine whether the molten salt thermal energy storage system participates in coordinated load change control.

[0029] In this embodiment, it is applied to the load control device, which is arranged between the coal-fired unit and the molten salt thermal energy storage system. There is thermal energy functional coupling between the coal-fired unit and the molten salt thermal energy storage system. This load control device can be based on the DSC control system. In this embodiment, this load control device is essentially a coordinated control system set up based on the DCS system (Distributed Control System, abbreviated as DSC, distributed control system). The DCS system, that is, the distributed control system, is a computerized system for industrial equipment in automated continuous and batch processes. It interconnects sensors, controllers, operator terminals, and actuators through a network and can monitor and control industrial processes in real time. The main functions of this DSC system include data acquisition and processing, monitoring and alarming, control and regulation, historical data recording, and trend analysis, etc. Through these functions, the DSC system can achieve goals such as automated control, optimized production processes, improved production efficiency and quality. The DSC system is widely used in industries such as chemical engineering, power, and pharmaceuticals. In this case, the DSC system is used to build the control logic for coordinated load change to improve the load change rate of the coal-fired unit coupled with the molten salt thermal energy storage system. Through the DSC system, real-time monitoring and control of the relevant valves and equipment of the molten salt thermal energy storage system can be achieved, ensuring the safe operation and efficient regulation of the system. In this way, it is ensured that the load control device in this embodiment has the functions of real-time monitoring, data analysis, and equipment regulation, and can receive the load command from the automatic generation controller (AGC), and compare it with the current actual load of the coal-fired unit, so as to judge whether the participation of the molten salt thermal energy storage system is required to coordinate load change control. Among them, AGC is the automatic generation controller (Automatic Generation Control, abbreviated as AGC), which is a control device used to adjust the output power of the generator set in the power system and can control the power of the coal-fired unit.

[0030] Specifically, this load control device is arranged between the coal-fired unit and the molten salt thermal energy storage system, playing a bridging role between the two. It can not only monitor the operating state of the coal-fired unit, but also accurately regulate relevant equipment according to the operating mode of the molten salt thermal energy storage system to achieve efficient conversion and utilization of thermal energy. For the convenience of subsequent description, in the embodiments of the present application and its subsequent embodiments, this device is used to represent this load control device.

[0031] In addition, in this embodiment, there is a thermal functional coupling between the coal-fired unit and the molten salt thermal energy storage system. That is, the high-temperature steam generated by the coal-fired unit can be used to drive the steam turbine to generate electricity. At the same time, part of the steam will be extracted and fed into the molten salt thermal energy storage system to heat the molten salt, realizing the storage of thermal energy. When heat needs to be released, the hot molten salt in the molten salt system can release the heat to generate steam and drive the steam turbine to generate electricity again, thus realizing the flexible conversion and efficient utilization of thermal energy.

[0032] In this embodiment, it is first necessary to determine whether to intercept and determine the load command difference. First, real-time monitoring is required. This load control device receives the load command sent by the automatic generation control (AGC) in real time and monitors the current actual load of the coal-fired unit. Then, the difference calculation is carried out. Specifically, by comparing the AGC load command with the current actual load of the unit, the difference between the two is calculated. If the difference exceeds the preset threshold, it is determined that the molten salt thermal energy storage system needs to perform a variable load operation.

[0033] 102. If it is determined that the molten salt thermal energy storage system participates in coordinated variable load control, then based on the operating states of the cold salt pump and the hot salt pump in the molten salt thermal energy storage system, the operating mode of the molten salt thermal energy storage system is judged.

[0034] When it is determined that the molten salt thermal energy storage system participates in coordinated variable load control, next, it is necessary to determine the current operating mode of the molten salt thermal energy storage system. Specifically, there are two operating modes, namely the heat storage mode and the heat release mode. Among them, the heat storage mode refers to the process in which the molten salt thermal energy storage system absorbs heat from an external heat source (such as the steam of a coal-fired unit) and stores this heat. In this process, the low-temperature molten salt in the cold salt tank is pumped by the molten salt pump to the heat absorber or heat exchanger, absorbs the heat from the coal-fired unit, and after the temperature rises, it becomes high-temperature molten salt, and then is stored in the hot salt tank. In this process, the molten salt thermal energy storage system can store the thermal energy generated by the coal-fired unit at low load or with excess heat for use when needed, improving the energy utilization efficiency. At the same time, it also helps the coal-fired unit better adapt to the fluctuations of the grid load, reduces the minimum stable combustion load of the unit by storing excess heat, enhances the peak shaving ability of the unit, and optimizes the distribution and use of thermal energy, reducing the waste of thermal energy caused by load changes and improving the thermal economy of the entire system.

[0035] For the exothermic mode, the exothermic mode refers to the process in which the stored thermal energy is released to generate steam or other forms of thermal energy to meet the power generation or other energy consumption needs. The high-temperature molten salt is pumped out from the hot salt tank and transfers heat to water or other working fluids through a heat exchanger, turning them into steam or high-temperature liquids for driving a steam turbine to generate electricity or providing industrial heat. During this process, the molten salt thermal energy storage system will quickly release the stored thermal energy and convert it into available thermal energy or electrical energy to meet the peak load demand of the power grid or the thermal energy demand of industrial production. During the peak load period of the power grid, the stored heat is released to increase the power generation, improve the output of the unit, and ensure the stability of power supply. In this way, it can not only provide a stable heat source for industrial production to meet the heat demand of industries such as food processing and textile, but also improve the comprehensive utilization efficiency of energy.

[0036] Based on this, it can be known that in the heat storage mode, the molten salt, as the storage medium of thermal energy, absorbs heat from an external heat source, causing its temperature to rise. The specific heat capacity of the molten salt is relatively large, enabling it to store a large amount of thermal energy in a relatively small volume. At the same time, the molten salt remains in a liquid state during the heat storage process, having good fluidity and heat transfer performance, which is convenient for heat transfer and storage. In the exothermic mode, the stored high-temperature molten salt transfers heat to water or other working fluids through a heat exchanger, turning them into steam or high-temperature liquids. This process is the reverse process of the heat storage process. By controlling the flow rate of the molten salt and the efficiency of the heat exchanger, precise control of the released heat can be achieved to meet different energy consumption needs.

[0037] Based on the above analysis, it can be seen that the functions of the molten salt thermal energy storage system in different modes are different. Therefore, during the process of controlling the load of the coupled coal-fired unit, it is necessary to consider the influence of different modes on the control process, and then adopt a reasonable control method to control the relevant valves.

[0038] Furthermore, during the process of judging the operation mode of the molten salt thermal energy storage system, it is generally based on monitoring the operation parameters of the cold salt pump and the hot salt pump, such as flow rate, pressure, etc., to judge the operation mode of the molten salt thermal energy storage system.

[0039] In this way, by monitoring the cold salt pump and the hot salt pump, the operation mode of the molten salt thermal energy storage system can be analyzed and determined. Considering the differences in the functions of the molten salt thermal energy storage system in different modes, it lays a foundation for the accuracy of subsequent relevant valve control.

[0040] 103. Control the main steam extraction valve and the reheater extraction valve according to the operation mode of the molten salt thermal energy storage system to improve the load change rate.

[0041] Among them, the main steam extraction valve is arranged between the boiler of the coal-fired unit and the high-pressure cylinder of the coal-fired unit, and is used to extract steam into the molten salt heat storage system; the reheat extraction valve is arranged between the high-pressure cylinder and the intermediate-pressure cylinder of the coal-fired unit, and is used to extract steam into the molten salt heat storage system.

[0042] In this embodiment, for the main steam extraction valve, this valve is arranged between the boiler of the coal-fired unit and the high-pressure cylinder of the coal-fired unit, and it can control the steam flow rate extracted from the high-pressure cylinder. Therefore, in the molten salt heat storage mode, according to the load command difference, the valve opening is adjusted to control the steam flow rate to optimize the heat storage process. And in the molten salt heat release mode, the valve opening is also adjusted according to the load command difference to control the steam flow rate to optimize the heat release process. In this way, based on the control of the main steam extraction valve opening, the optimization of the heat storage and heat dissipation processes can be realized, thereby improving the overall variable load adjustment efficiency of the coal-fired unit, without the need to control the boiler and the high-pressure cylinder, saving the need to wait for them to run before responding to load changes, and thus improving the adjustment speed of the variable load rate.

[0043] For the reheat extraction valve, this reheat extraction valve is arranged between the high-pressure cylinder and the intermediate-pressure cylinder of the coal-fired unit, and is used to control the steam flow rate extracted from the intermediate-pressure cylinder. In this way, in the molten salt heat storage mode, the valve opening can be adjusted according to the load command difference to control the steam flow rate to optimize the heat storage process. And in the molten salt heat release mode, the valve opening is also adjusted according to the load command difference to control the steam flow rate to optimize the heat release process. In this way, based on the control of the reheat extraction valve opening, the optimization of the heat storage and heat dissipation processes can be realized, thereby improving the overall variable load adjustment efficiency of the coal-fired unit, without the need to control the intermediate-pressure cylinder and the high-pressure cylinder, saving the need to wait for them to run before responding to load changes, and thus improving the adjustment speed of the variable load rate.

[0044] It should be noted that in this embodiment, for the opening control process of the main steam extraction valve and the reheat extraction valve, it can be based on a preset curve. This preset curve can be understood as data obtained through experiments based on historical data, and can represent the relationship between different load command differences and the required valve opening in different operating modes of the molten salt heat storage system. In this way, it is ensured that the valve opening corresponding to the current load command difference can be known in different operating modes, ensuring the accuracy of load control.

[0045] Through the above execution process, based on the control of the main steam extraction valve and the reheat extraction valve, the main steam extraction valve and the reheat extraction valve can be accurately controlled according to the load command difference and the operating mode of the molten salt heat storage system, so as to realize the efficient coordination between the coal-fired unit and the molten salt heat storage system, improve the variable load rate, and meet the rapid change requirements of the grid load.

[0046] Based on this, this embodiment provides a load control method for a coal-fired unit. Compared with the prior art, in the load control process of the coal-fired unit in this application, by real-time monitoring the difference between the load command and the current actual load of the unit, it is judged whether the molten salt thermal energy storage system needs to participate. Once it is determined that participation is required, the load control device will precisely control the relevant valves according to the operating mode (thermal energy storage or heat release) of the molten salt thermal energy storage system. This control process can directly and precisely control the valves in the coal-fired unit and its coupled molten salt thermal energy storage system, without the need to control other facilities in the molten salt thermal energy storage system and the coal-fired unit. Compared with setting through other operating facilities, directly controlling the valves in the control loop can directly and quickly respond to load changes and optimize the operation of the molten salt system, without waiting for the time required for the operation adjustment of each facility in the molten salt thermal energy storage system and the coal-fired unit. Thus, the load change rate of the coal-fired unit can be significantly improved, solving the problems of low load change rate and slow response in the prior art. In addition, by precisely controlling the main steam extraction valve and the reheater extraction valve, this application realizes the precise control of the valves in the system loop, eliminating the control process of other facilities in the loop and simplifying the load control process. Furthermore, based on the method of this application, the control is directly based on the valves, without the need to adjust the operating conditions of the facilities in the system. Therefore, during the process of stable load change, the frequent start-stop and large-scale adjustment processes of the corresponding equipment in the coal-fired unit and its molten salt thermal energy storage system are reduced, the equipment wear is reduced, and the service life of the equipment in the coal-fired unit and its coupled molten salt thermal energy storage system is extended.

[0047] In some embodiments, as a further description and refinement of the foregoing embodiments, in the foregoing embodiments, "Step 102, judging the operating mode of the molten salt thermal energy storage system based on the operating states of the cold salt pump and the hot salt pump in the molten salt thermal energy storage system" includes:

[0048] On the one hand, when it is determined that the cold salt pump is operating, the molten salt flow rate at the outlet of the cold salt pump is greater than the first preset flow rate value, and the hot salt pump is not operating, it is determined that the operating mode of the molten salt thermal energy storage system is the thermal energy storage mode;

[0049] On the other hand, when it is determined that the cold salt pump is operating and the molten salt flow rate at the outlet of the cold salt pump is greater than the first preset flow rate value, and the hot salt pump is operating and the molten salt flow rate at the outlet of the hot salt pump is greater than the second preset flow rate value, it is determined that the operating mode of the molten salt thermal energy storage system is the heat release mode.

[0050] Based on the description of the foregoing embodiments, since the functions of the molten salt thermal energy storage system in different operating modes and its influence on the coal-fired unit are different, therefore, when determining how to precisely control the valves in the coal-fired unit and its coupled molten salt thermal energy storage system, the judgment of the operating mode of the molten salt thermal energy storage system is crucial. Based on this, in this step, the method for judging the operating mode of the molten salt thermal energy storage system can be as follows:

[0051] When determining whether it is in the heat storage mode, the following steps (a1)-(a3) need to be specifically followed.

[0052] (a1) Determine whether the cold salt pump is running and the flow rate meets the standard. In this process, the cold salt pump extracts low-temperature molten salt from the cold salt tank and transports it to the heat absorption heat exchanger. When the cold salt pump is running, the device monitors the molten salt flow rate at its outlet. If the flow rate is greater than the first preset flow rate value, it indicates that sufficient cold salt is being transported to the heat exchanger to absorb the heat from the coal-fired unit.

[0053] (a2) Determine whether the hot salt pump is not running. The hot salt pump is responsible for transporting high-temperature molten salt from the hot salt tank to the heat release heat exchanger. In the heat storage mode, the hot salt pump does not participate in the operation because the main task of the system at this time is to store heat rather than release heat.

[0054] (a3) Perform the heat storage operation. When the above conditions are met, the device determines that the molten salt heat storage system is in the heat storage mode. At this time, the steam from the coal-fired unit transfers heat to the molten salt, causing its temperature to rise and be stored in the hot salt tank.

[0055] When determining whether it is in the heat release mode, the following steps (b1)-(b3) need to be specifically followed.

[0056] (b1) Determine whether the cold salt pump is running and the flow rate meets the standard. Similar to the heat storage mode, the cold salt pump still needs to run and transport cold salt to the heat exchanger, and the flow rate needs to be greater than the first preset flow rate value. This is to ensure that there is sufficient molten salt participating in the heat exchange. Whether storing or releasing heat, the cold salt pump is required to provide molten salt.

[0057] (b2) Determine that the hot salt pump is running and the flow rate meets the standard. The hot salt pump starts to run and transports the high-temperature molten salt stored in the hot salt tank to the heat release heat exchanger. When the molten salt flow rate at the outlet of the hot salt pump is greater than the second preset flow rate value, it indicates that a sufficient amount of high-temperature molten salt is being transported to the heat exchanger to release heat to water or other working fluids to generate steam for power generation.

[0058] (b3) Perform the heat release operation. When the operating conditions of both the cold salt pump and the hot salt pump are met simultaneously, the device determines that the molten salt heat storage system is in the heat release mode. At this time, the high-temperature molten salt releases heat in the heat release heat exchanger to generate steam to assist the coal-fired unit in power generation.

[0059] Based on the above judgment process, it can be seen that when the device determines the operating mode of the molten salt heat storage system, it mainly realizes the automatic control process through flow monitoring, pump status monitoring, and based on the monitoring results.

[0060] During the process of flow monitoring, this device monitors the flow rate of molten salt in real time through flow sensors installed at the outlets of the cold salt pump and the hot salt pump. These sensors can accurately measure the flow velocity of the molten salt and feedback the data to the control system. During the process of pump status monitoring, this device monitors the operating status of the cold salt pump and the hot salt pump, including parameters such as whether it is running, operating power, rotational speed, etc., to ensure the normal operation of the pump.

[0061] Once this device determines the operating mode of the molten salt thermal energy storage system based on the monitoring data, it will automatically execute the corresponding control strategy. For example, in the heat storage mode, the control system will adjust the valve opening to allow more steam to flow into the molten salt thermal energy storage system for heat storage; in the heat release mode, the valve will be adjusted to allow more high-temperature molten salt to flow into the heat release heat exchanger to release heat.

[0062] It should be noted that in this embodiment, both the first preset flow value and the second preset flow value can be set according to the specific parameters of the molten salt thermal energy storage system, and are not specifically limited herein, and can be selected and determined based on the actual molten salt thermal energy storage system.

[0063] In addition, in this embodiment, when determining the operating mode of the molten salt thermal energy storage system, safety and stability guarantee measures are also provided, which are specifically divided into the following types:

[0064] Flow protection mechanism: If the flow rate of the cold salt pump or the hot salt pump is lower than the preset minimum flow value, this device will also trigger an alarm and automatically take measures, such as adjusting the operating parameters of the pump or closing relevant valves, to prevent equipment damage or efficiency reduction caused by insufficient flow.

[0065] Temperature monitoring: This device also monitors the temperature of the molten salt to ensure that it is within a safe operating range. If the temperature exceeds the allowable range, this device will automatically adjust the operating parameters or enter the protection mode to prevent damage to the equipment caused by overheating or overcooling.

[0066] Redundant design: To improve the reliability of the coal-fired unit, key equipment such as the cold salt pump and the hot salt pump are usually equipped with redundant equipment. When this device detects a failure of the main equipment during the above detection process, the standby equipment can be controlled to start to ensure the stable operation of the coal-fired unit.

[0067] In some embodiments, as a further description and refinement of the foregoing embodiments, the foregoing embodiment "Step 103. Control the main steam extraction valve and the reheat extraction valve according to the operating mode of the molten salt thermal energy storage system" may specifically include when executed:

[0068] When the molten salt thermal energy storage system is in the thermal energy storage mode, control the main steam extraction valve to adjust the opening degree at a preset first rate according to the load command difference, and set the main steam extraction valve to the PID automatic regulation mode with the adjusted opening degree after the adjustment is completed;

[0069] When the molten salt thermal energy storage system is in the thermal energy storage mode, control the reheat extraction valve to adjust the opening degree at a preset second rate according to the load command difference, and set the reheat extraction valve to the PID automatic regulation mode with the adjusted opening degree after the adjustment is completed.

[0070] Based on the description of the foregoing embodiments, since the molten salt thermal energy storage system has different impacts on the coal-fired power unit under different operating modes, when specifically controlling the main steam extraction valve and the reheat extraction valve, it is necessary to control and manage according to the mode.

[0071] Based on this, when the molten salt thermal energy storage system is in the thermal energy storage mode, the process of controlling the main steam extraction valve can be as follows:

[0072] First, adjust the opening degree according to the load command difference. Since the load command difference reflects the gap between the current load demand and the actual load, it is necessary to use this as a basis in the subsequent valve adjustment process. Therefore, the opening degree of the main steam extraction valve can be adjusted at a preset first rate according to the calculated load command difference. Among them, the preset first rate is preset according to factors such as the characteristics of the coal-fired power unit and the molten salt thermal energy storage system, the bearing capacity of the equipment, and the requirements of the load change rate, with the aim of ensuring that the adjustment of the valve opening degree can quickly respond to the load change and will not cause too much impact on the entire system and equipment. For example, if the load command difference is large, it may be necessary to increase the opening degree at a faster rate to quickly increase the steam flow rate to meet the thermal energy storage demand, while if the difference is small, it is adjusted at a slower rate to avoid over-adjustment.

[0073] Then, set the valve to the PID automatic regulation mode after the adjustment. Among them, after the adjustment is completed, the main steam extraction valve is set to the PID automatic regulation mode. Among them, PID (Proportion-Integral-Differential) control is a common automatic control algorithm that can automatically adjust the control quantity according to the deviation between the actual measurement value and the set value to achieve precise control. In the PID automatic regulation mode, the main steam extraction valve will automatically fine-tune the opening degree according to the real-time load command difference and the feedback of the system to ensure that the steam flow rate matches the load demand and maintain the stable operation of the system.

[0074] When the molten salt thermal energy storage system is in the thermal energy storage mode, the process of controlling the reheat extraction valve can be as follows:

[0075] First, adjust the opening according to the load command difference. Similar to the main steam extraction valve, the reheat extraction valve also receives the same load command difference signal, which is also based on the comparison result between the AGC load command and the actual load of the current unit. Therefore, the opening of the reheat extraction valve can be adjusted according to the load command difference at a preset second rate. Among them, the preset second rate also takes into account factors such as the characteristics of the system and the operating requirements of the equipment, and may be different from the adjustment rate of the main steam extraction valve. This is because the position and function of the reheat extraction valve are different from those of the main steam extraction valve, and a suitable adjustment rate needs to be set according to its own working conditions.

[0076] Then, after the adjustment, the valve is also set to the PID automatic adjustment mode. After the adjustment is completed, the reheat extraction valve is set to the PID automatic adjustment mode, so that it can automatically adjust the opening according to the real-time feedback, ensuring the stable and precise control of the reheat steam flow and meeting the demand for reheat steam during the heat storage process.

[0077] It should be noted that in this embodiment, based on the existence of a certain functional relationship between the valve opening and the steam flow, generally, the larger the valve opening, the larger the steam flow. The specific control size of the opening can be controlled according to the chart summarized from historical data, such as Figure 2 shown, the opening (opening ratio) of the main steam extraction valve to be adjusted is also different under different load command differences (i.e., the difference between the AGC load command and the actual load). Then, controlling based on this method may lack the realization of precise control of the valve opening.

[0078] Based on the above control process, in the heat storage mode, by controlling the openings of the main steam extraction valve and the reheat extraction valve, the excess steam generated by the coal-fired unit is introduced into the molten salt heat storage system, and the heat of the steam is used to heat the molten salt to realize the storage of thermal energy. This process not only improves the energy utilization efficiency but also enhances the flexibility and peak shaving ability of the system, enabling the coal-fired unit to better adapt to the changes in the grid load. At the same time, by precisely controlling the valve opening, the effective regulation of the steam flow can be achieved, and then the amount of steam entering the molten salt heat storage system can be controlled to meet the requirements of the heat storage or heat release process. In addition, after the precise control of the valve, automatic control is also based on PID. Based on the PID automatic adjustment mode, the valve opening can be automatically adjusted according to the load command difference and the real-time feedback of the steam flow, ensuring the precise regulation of the steam flow. That is, after the precise and rapid opening adjustment of the valve, small-amplitude adjustment changes can be made in real time based on the PID automatic control mode, thus maintaining the stable operation of the system.

[0079] In some embodiments, as a further description and refinement of the foregoing embodiments, "Step 103, control the main steam extraction valve and the reheat extraction valve according to the operating mode of the molten salt heat storage system" in the foregoing embodiments includes:

[0080] When the molten salt thermal energy storage system is in the heat release mode, control the main steam extraction valve to adjust the opening degree at a preset third rate according to the load command difference, and set the main steam extraction valve to the PID automatic control mode with the adjusted opening degree after the adjustment is completed;

[0081] When the molten salt thermal energy storage system is in the heat release mode, control the reheat steam extraction valve to adjust the opening degree at a preset fourth rate according to the load command difference, and set the reheat steam extraction valve to the PID automatic control mode with the adjusted opening degree after the adjustment is completed.

[0082] In the heat release mode, the high-temperature molten salt stored in the hot salt tank is pumped to the heat release heat exchanger. In the heat exchanger, the high-temperature molten salt transfers heat to water or other working fluids, turning them into steam or high-temperature liquids for driving the steam turbine to generate electricity. At the same time, based on the description of the foregoing embodiments, since the load command difference is calculated based on the load command of the automatic generation control (AGC) and the actual load of the current unit, during the process of controlling the valve, this load command difference is the main basis for adjusting the opening degree of the main steam extraction valve.

[0083] Therefore, during the process of controlling the opening degree of the main steam extraction valve, the opening degree of the main steam extraction valve can be adjusted at a preset third rate according to the load command difference. The preset third rate is preset according to the characteristics and equipment requirements of the molten salt thermal energy storage system and its coal-fired unit, aiming to ensure that the adjustment of the valve opening degree can quickly respond to load changes without causing excessive impact on the system and equipment. After the adjustment is completed, the main steam extraction valve is set to the PID automatic control mode. Based on the description of the foregoing embodiments, it can be known that the PID control is an automatic control algorithm that can automatically adjust the control quantity according to the deviation between the actual measurement value and the set value. In this way, in the PID automatic control mode, the main steam extraction valve will automatically fine-tune the opening degree according to the real-time load command difference and the feedback of the system to ensure that the steam flow rate matches the load demand and maintain the stable operation of the system.

[0084] During the process of controlling the opening degree of the reheat steam extraction valve, it is also necessary to adjust the opening degree based on the load command difference signal. Specifically, according to the load command difference, the opening degree of the reheat steam extraction valve is adjusted at a preset fourth rate. Among them, the preset fourth rate and the foregoing preset third rate are both set considering factors such as the characteristics of the molten salt thermal energy storage system and the operating requirements of the coal-fired unit equipment, and may be different from the rate of the main steam extraction valve when adjusting the opening degree. This is because the position and function of the reheat steam extraction valve are different from those of the main steam extraction valve, and a suitable adjustment rate needs to be set according to its own working conditions. After the adjustment is completed, the reheat steam extraction valve is also set to the PID automatic control mode, so that it can also automatically adjust the opening degree according to the real-time feedback, ensuring the stable and precise control of the reheat steam flow rate and meeting the demand for reheat steam during the heat release process.

[0085] In this way, through the above control process, a function of adjusting the steam volume entering the molten salt thermal energy storage system by controlling the opening degrees of the main steam extraction valve and the reheat extraction valve can be realized, so as to control the cooling rate and heat release rate of the molten salt. This helps to flexibly adjust the power generation according to the grid load demand and achieve the effective utilization of energy. In the heat release mode of the molten salt thermal energy storage system, by precisely controlling the opening degrees of the main steam extraction valve and the reheat extraction valve and combining with the PID automatic regulation mode, precise regulation of the steam flow rate can be achieved, ensuring the stable operation of the system. This not only improves the energy utilization efficiency, but also enhances the flexibility and peak shaving capacity of the system, enabling the coal-fired unit to better adapt to the changes in the grid load.

[0086] In some embodiments, as a further description and refinement of the foregoing embodiments, in certain cases, the molten salt thermal energy storage system is further provided with a regulating valve at the molten salt side inlet of the main steam superheater, and the regulating valve at the molten salt side inlet of the main steam superheater is arranged between the main steam superheater of the salt thermal energy storage system and the cold salt tank of the salt thermal energy storage system. Based on this, after the step 103 of "controlling the main steam extraction valve and the reheat extraction valve according to the operation mode of the molten salt thermal energy storage system" in the foregoing embodiment, this embodiment can also control this valve, including:

[0087] When the molten salt thermal energy storage system is in the heat release mode, control the regulating valve at the molten salt side inlet of the main steam superheater to adjust the opening degree according to the load command difference at a preset fifth rate, and after the adjustment is completed, set the regulating valve at the molten salt side inlet of the main steam superheater to the PID automatic regulation mode with the adjusted opening degree;

[0088] When the molten salt thermal energy storage system is in the heat storage mode, control the regulating valve at the molten salt side inlet of the main steam superheater to adjust the opening degree according to the load command difference at a preset sixth rate, and after the adjustment is completed, set the regulating valve at the molten salt side inlet of the main steam superheater to the PID automatic regulation mode with the adjusted opening degree.

[0089] In this embodiment, the energy conversion during the heat storage and heat release processes is actually as follows: In the heat storage mode, by controlling the opening degree of the regulating valve at the molten salt side inlet of the main steam superheater heat exchanger, the low-temperature molten salt in the cold salt tank can be introduced into the main steam superheater heat exchanger to absorb the steam heat from the coal-fired unit, thereby realizing the storage of thermal energy. In the heat release mode, by controlling the opening degree of this valve, the high-temperature molten salt in the hot salt tank is introduced into the main steam superheater heat exchanger to release heat to generate superheated steam, assisting the coal-fired unit in power generation. By controlling this valve, not only can the energy utilization efficiency be further improved, but also the flexibility and peak shaving capacity of the system are enhanced, enabling the coal-fired unit to better adapt to the changes in the grid load. It should be noted that in this embodiment, there is a certain functional relationship between the valve opening degree and the molten salt flow rate. Generally, the larger the valve opening degree, the larger the molten salt flow rate.

[0090] Based on the above analysis, it can be seen that when controlling the regulating valve at the molten salt side inlet of the main steam superheater heat exchanger, it is necessary to control it based on the current operating mode of the molten salt heat storage system. Therefore, the specific control process is divided into specific control processes under different modes.

[0091] Among them, when the molten salt heat storage system is in the heat release mode, first adjust the opening degree according to the load command difference. Specifically, it is necessary to adjust the opening degree of the regulating valve at the molten salt side inlet of the main steam superheater heat exchanger at a preset fifth rate based on this load command difference. The preset fifth rate is similar to the aforementioned preset first rate to preset fourth rate, and is preset according to factors such as the characteristics of the coal-fired unit and the coupled molten salt heat storage system, the bearing capacity of the equipment, and the requirements of the variable load rate. In the heat release mode, adjusting the opening degree of this valve can control the molten salt flow rate entering the main steam superheater heat exchanger, thereby affecting the superheat degree of steam and the power generation power. Then, after the opening degree adjustment is completed, the regulating valve at the molten salt side inlet of the main steam superheater heat exchanger is set to the PID automatic adjustment mode. In the PID automatic adjustment mode, the valve will automatically fine-tune the opening degree according to the real-time load command difference and the feedback of the system to ensure that the molten salt flow rate matches the load demand and maintain the stable operation of the system.

[0092] When the molten salt heat storage system is in the heat storage mode, it is also necessary to adjust the opening degree of the regulating valve at the molten salt side inlet of the main steam superheater heat exchanger at a preset sixth rate according to the load command difference. The preset sixth rate also takes into account factors such as the characteristics of the coal-fired unit and the coupled molten salt heat storage system and the operating requirements of the equipment in the heat storage mode. In this way, in the heat storage mode, adjusting the opening degree of this valve can control the cold salt flow rate entering the main steam superheater heat exchanger, thereby affecting the heat storage efficiency. Then, after the adjustment is completed, the regulating valve at the molten salt side inlet of the main steam superheater heat exchanger is set to the PID automatic adjustment mode, enabling it to automatically adjust the opening degree according to the real-time feedback to ensure the stable and precise control of the molten salt flow rate and meet the requirements of the molten salt flow rate during the heat storage process.

[0093] Through the above control process, by precisely controlling the opening degree of the molten salt side inlet regulating valve of the main steam superheater heat exchanger, the effective regulation of the molten salt flow rate between the main steam superheater of the salt energy storage system and the cold salt tank of the salt energy storage system can be achieved, thereby further improving the rate of controlling the heat storage or heat release process. In addition, based on the PID automatic regulation mode, it can automatically adjust the valve opening degree according to the load command difference and the real-time feedback of the molten salt flow rate, ensuring the precise regulation of the molten salt flow rate between the main steam superheater and the cold salt tank, and facilitating the further improvement of the response efficiency of variable load while maintaining the stable operation of the coal-fired unit.

[0094] In some embodiments, as a further description and refinement of the foregoing embodiments, the molten salt heat storage system is further provided with a reheat superheater molten salt side inlet regulating valve, and the reheat superheater molten salt side inlet regulating valve is arranged between the reheat superheater of the salt heat storage system and the cold salt tank of the salt heat storage system.

[0095] After the foregoing embodiment "Step 103, control the main steam extraction valve and the reheat extraction valve according to the operation mode of the molten salt heat storage system", the control of the reheat superheater molten salt side inlet regulating valve may further include:

[0096] When the molten salt heat storage system is in the heat release mode, control the reheat superheater molten salt side inlet regulating valve to adjust the opening degree according to the load command difference at a preset seventh rate, and set the reheat superheater molten salt side inlet regulating valve to the PID automatic regulation mode with the adjusted opening degree after the adjustment ends;

[0097] When the molten salt heat storage system is in the heat storage mode, control the reheat superheater molten salt side inlet regulating valve to adjust the opening degree according to the load command difference at a preset eighth rate, and set the reheat superheater molten salt side inlet regulating valve to the PID automatic regulation mode with the adjusted opening degree after the adjustment ends.

[0098] In this embodiment, since the reheat superheater molten salt side inlet regulating valve is arranged between the reheat superheater of the salt heat storage system and the cold salt tank of the salt heat storage system, therefore, in the heat storage mode, by controlling the opening degree of the reheat superheater molten salt side inlet regulating valve, the low-temperature molten salt in the cold salt tank can be introduced into the reheat superheater to absorb the steam heat from the coal-fired unit and realize the storage of thermal energy. In the heat release mode, by controlling the opening degree of this valve, the high-temperature molten salt in the hot salt tank can be introduced into the reheat superheater to release heat to generate superheated steam to assist the coal-fired unit in power generation. This process not only improves the energy utilization efficiency, but also enhances the flexibility and peak shaving capacity of the system, enabling the coal-fired unit to better adapt to the changes in the grid load.

[0099] Specifically, when the molten salt thermal energy storage system is in the heat release mode, the opening degree of the regulating valve at the molten salt side inlet of the reheater and superheater can be adjusted according to the calculated load command difference at a preset seventh rate. In the heat release mode, adjusting the opening degree of this valve can control the molten salt flow rate entering the reheater and superheater, thereby affecting the superheat degree of steam and the power generation. After the adjustment of the opening degree of this valve is completed, the regulating valve at the molten salt side inlet of the reheater and superheater can also be set to the PID automatic regulation mode. In the PID automatic regulation mode, the valve will automatically fine-tune the opening degree according to the real-time load command difference and the feedback of the system to ensure that the molten salt flow rate matches the load demand and maintain the stable operation of the system.

[0100] In addition, when the molten salt thermal energy storage system is in the heat storage mode, it is also necessary to adjust the opening degree according to the load command difference, that is, according to the load command difference, adjust the opening degree of the regulating valve at the molten salt side inlet of the reheater and superheater at a preset eighth rate. In this way, in the heat storage mode, adjusting the opening degree of this valve can control the cold salt flow rate entering the reheater and superheater, thereby affecting the heat storage efficiency. Similarly, after the adjustment of this valve is completed, the regulating valve at the molten salt side inlet of the reheater and superheater is set to the PID automatic regulation mode, so that it can automatically adjust the opening degree according to the real-time feedback, ensuring the stable and precise control of the molten salt flow rate and meeting the requirements of the molten salt flow rate during the heat storage process.

[0101] It should be noted that in this embodiment, there is a certain functional relationship between the valve opening degree and the molten salt flow rate. Generally, the larger the valve opening degree, the larger the molten salt flow rate. By precisely controlling the valve opening degree, the effective regulation of the molten salt flow rate can be achieved, and further the rate of the heat storage or heat release process can be controlled. In addition, both the preset seventh rate and the preset eighth rate are preset according to factors such as the characteristics of the entire system, the bearing capacity of the equipment, and the requirements of the variable load rate, and the rates between the two can be different.

[0102] In some embodiments, as a further description and refinement of the foregoing embodiments, the molten salt thermal energy storage system is further provided with a high-temperature molten salt pump and a steam generator water supply valve; wherein, the high-temperature molten salt pump is arranged between the cold salt tank of the molten salt thermal energy storage system and the main steam superheater of the molten salt thermal energy storage system; the steam generator water supply valve is arranged between the steam generator of the molten salt thermal energy storage system and the feed water pump of the molten salt thermal energy storage system. Based on this, after the step 103 in the foregoing embodiment "control the main steam extraction valve and the reheater extraction valve according to the operation mode of the molten salt thermal energy storage system", the method further includes:

[0103] When the molten salt thermal energy storage system is in the heat release mode, control the high-temperature molten salt pump to increase the frequency at a ninth rate according to the load command difference, and after the frequency is increased to the target frequency, set the high-temperature molten salt pump to the PID automatic regulation mode;

[0104] When the molten salt thermal energy storage system is in the heat release mode, control the water inlet valve of the steam generator to adjust the opening degree at the tenth rate according to the load command difference, and set the water inlet valve of the steam generator to the PID automatic regulation mode after the adjustment.

[0105] In this embodiment, the relationship between the molten salt flow rate and heat release is actually: the higher the frequency of the high-temperature molten salt pump, the greater the molten salt flow rate, and the more heat is released. By precisely controlling the frequency of the high-temperature molten salt pump, the effective regulation of the heat release rate can be achieved, thereby controlling the steam generation amount and power generation capacity.

[0106] The relationship between water volume control and steam generation is: the larger the opening degree of the water inlet valve of the steam generator, the more water enters the steam generator, and the more steam is generated. By precisely controlling the opening degree of the water inlet valve, the effective regulation of the steam generation amount can be achieved to meet the power generation requirements.

[0107] Therefore, based on the above analysis, it can be known that in the heat release mode, the control of the high-temperature molten salt pump and the water inlet valve of the steam generator can also affect the heat release process of the molten salt thermal energy storage system, and then affect the load change of the coal-fired unit coupled with it.

[0108] Therefore, in this process, the control process of the high-temperature molten salt pump can be: First, increase the frequency according to the load command difference. Among them, since the load command difference is the difference between the required load and the actual load, this difference can be used to guide the frequency adjustment of the high-temperature molten salt pump. Therefore, according to the load command difference, increase the frequency of the high-temperature molten salt pump at the preset ninth rate. In the heat release mode, increasing the frequency of the high-temperature molten salt pump can increase the circulating flow rate of the molten salt, so that more high-temperature molten salt is transported from the hot salt tank to the main steam superheater heat exchanger, thereby releasing more heat for steam generation. Then, when the frequency of the high-temperature molten salt pump is increased to the target frequency, set it to the PID automatic regulation mode. In the PID automatic regulation mode, the high-temperature molten salt pump will automatically fine-tune the frequency according to the real-time load command difference and the feedback of the system to ensure that the molten salt flow rate matches the load demand and maintain the stable operation of the system.

[0109] The control process of the water inlet valve of the steam generator can be: Similarly, the load command difference is also used to guide the opening degree adjustment of the water inlet valve of the steam generator. Therefore, according to the load command difference, adjust the opening degree of the water inlet valve of the steam generator at the preset tenth rate. In the heat release mode, adjusting the opening degree of this valve can control the amount of water entering the steam generator, thereby affecting the steam generation rate and amount. Then, after the adjustment is completed, set the water inlet valve of the steam generator to the PID automatic regulation mode, so that it can automatically adjust the opening degree according to the real-time feedback to ensure the stable and precise control of the water volume and meet the requirements of steam generation.

[0110] It should be noted that both the preset ninth rate and the preset tenth rate are preset according to factors such as the characteristics of the entire system, the bearing capacity of the equipment, and the requirements of the variable load rate, and the rates between the two can be different.

[0111] From the above control process, it can be seen that in the heat release mode of the molten salt thermal energy storage system, by precisely controlling the frequency of the high-temperature molten salt pump and the opening of the water inlet valve of the steam generator, and combining with the PID automatic adjustment mode, precise adjustment of the molten salt flow rate and water volume can be achieved to ensure the stable operation of the system. This process not only improves the energy utilization efficiency but also enhances the flexibility and peak shaving capacity of the system, enabling the coal-fired unit to better adapt to the changes in the grid load.

[0112] In some embodiments, as a further description and refinement of the foregoing embodiments, the method of this embodiment further includes:

[0113] When the molten salt thermal energy storage system is in the heat release mode, after the frequency of the high-temperature molten salt pump is adjusted, the frequency is maintained unchanged until the absolute value of the difference between the actual pressure and the target pressure of the steam supply header is less than the preset pressure difference;

[0114] and / or,

[0115] When the molten salt thermal energy storage system is in the heat release mode, after the opening of the water inlet valve of the steam generator is adjusted, the opening is maintained unchanged until the steam temperature at the outlet of the steam generator reaches the preset temperature range.

[0116] In this embodiment, the steam supply header is used to aggregate and distribute steam. The steam generated by the boiler can be distributed to each steam-using point to ensure the stable operation of the system. Based on this, in this embodiment, when the molten salt thermal energy storage system is in the heat release mode, the frequency of the high-temperature molten salt pump is adjusted according to the load command difference. After the frequency is adjusted to the target frequency, the device will start to monitor the actual pressure of the steam supply header. Specifically, the device compares the actual pressure of the steam supply header with the target pressure and calculates the difference between the two. If the absolute value of this difference is less than the preset pressure difference, it means that the pressure of the steam supply header has been stabilized within the target range, and at this time, the frequency of the high-temperature molten salt pump remains unchanged. In this way, keeping the frequency of the high-temperature molten salt pump unchanged can maintain the stability of the molten salt flow rate, thereby ensuring the stability of heat release and the continuity of steam supply, and avoiding the problem of excessive actual pressure of the steam supply header.

[0117] In addition, during the process of controlling the opening degree of the feed water valve of the steam generator, when the molten salt thermal energy storage system is in the heat release mode, the opening degree of the feed water valve of the steam generator will be adjusted according to the load command difference. After the adjustment is completed, the device starts to monitor the steam temperature at the outlet of the steam generator. Among them, the process of steam temperature comparison and judgment is actually to compare the actual steam temperature at the outlet of the steam generator with the preset temperature range. If the actual steam temperature reaches the preset temperature range, it indicates that the operating state of the steam generator has stabilized, and at this time, the opening degree of the feed water valve of the steam generator remains unchanged. In this way, maintaining the opening degree of the feed water valve of the steam generator can keep the amount of water entering the steam generator stable, thereby ensuring the stability of the steam generation rate and quality and meeting the power generation requirements.

[0118] In this embodiment, the preset pressure difference and temperature range are preset according to factors such as the performance requirements of the molten salt thermal energy storage system, the operating parameters of the device, and safety standards. These preset values provide a reference benchmark for the stable operation of the system. By keeping the frequency of the high-temperature molten salt pump and the opening degree of the feed water valve of the steam generator unchanged, it can ensure that the relevant equipment and devices maintain a stable operating state after reaching the set conditions, avoid fluctuations and instability caused by frequent adjustments, and improve the reliability and operating efficiency of the system. In addition, by monitoring the pressure of the steam supply header and the steam temperature at the outlet of the steam generator, the device can understand the current operating state in real time and make corresponding control decisions based on this to ensure the stable operation of the system.

[0119] Based on this, in the heat release mode of the molten salt thermal energy storage system, by monitoring the pressure of the steam supply header and the steam temperature at the outlet of the steam generator and making judgments according to the preset values, the device can automatically decide whether to keep the frequency of the high-temperature molten salt pump and the opening degree of the feed water valve of the steam generator unchanged. This process ensures that the coal-fired unit and its molten salt thermal energy storage system can maintain a stable operating state after reaching the stable operating conditions, improving the reliability and operating efficiency of the system.

[0120] In some embodiments, as a further description and refinement of the foregoing embodiments, the method of this embodiment further includes: when the absolute value of the difference between the actual load of the unit and the load command of the automatic generation controller is less than the preset load deviation value, controlling the main steam extraction valve and the reheater extraction valve to abort the opening degree adjustment operation, and setting the main steam extraction valve and the reheater extraction valve to the PID automatic adjustment mode.

[0121] In this embodiment, when the absolute value of the difference between the actual load of the unit and the load command of the automatic generation control (AGC) is less than the preset load deviation value, first, the load command difference is monitored. Among them, this device continuously monitors the difference between the actual load of the unit and the load command of the automatic generation control (AGC). This process is carried out in real time to ensure that the system can respond to load changes in a timely manner. Then, the difference condition is judged. Among them, when the absolute value of the monitored load command difference is less than the preset load deviation value, this device will determine that the current load demand is close to the actual load and there is no need to make large-scale opening adjustments. Among them, the preset load deviation value is preset according to the performance requirements and operation stability of the molten salt thermal energy storage system, and is used to determine when to stop the opening adjustment operation of the valve. After that, the opening adjustment operation is aborted. This device can control the main steam extraction valve and the reheater extraction valve to abort the execution of the opening adjustment operation, which means that the opening of the valve will remain at the current position and will not be further adjusted according to the load command difference. Finally, these two valves are set to the PID automatic adjustment mode. Specifically, the main steam extraction valve and the reheater extraction valve can be set to the PID automatic adjustment mode. In this mode, the valve will automatically fine-tune the opening according to the real-time load command difference and the feedback of the system to maintain the stable operation of the system. PID control can automatically adjust the control quantity according to the deviation between the actual measured value and the set value to achieve precise control.

[0122] This ensures that when the load command difference is small, the opening adjustment operation is aborted and directly set to the PID automatic adjustment mode, which can avoid system fluctuations caused by frequent adjustment of the valve opening and improve the stability of the system. The PID automatic adjustment mode can perform fine-tuning according to real-time feedback to ensure that the system parameters operate stably within the set range.

[0123] Furthermore, as a specific implementation scenario of the method in the above embodiment, in this implementation, a schematic diagram of the thermal energy interaction of a coal-fired unit coupled with a molten salt thermal energy storage system is also provided. Specifically, as Figure 3 shown, which includes: boiler (1), high-pressure cylinder (2), intermediate-pressure cylinder (3), main steam extraction valve (4), reheater extraction valve (5), main steam superheater (6), reheater superheater (7), main steam superheater molten salt side inlet regulating valve (8), reheater superheater molten salt side inlet regulating valve (9), cold salt tank (10), hot salt tank (11), cold salt pump (12), steam supply header (13), hot salt pump (14), steam generator (15), feed water pump (16), steam generator water supply valve (17).

[0124] Among them, the valves in this schematic diagram of the scenario can all be controlled by the method described in any of the above embodiments to achieve the load control function of the coal-fired unit, thereby improving the variable load response efficiency. Details are not described here, and the specific implementation can refer to the methods in the foregoing embodiments.

[0125] Further, as an implementation of the method described above Figures 1 to 3 Another embodiment of the present application further provides a load control device for a coal-fired unit. The device embodiment corresponds to the foregoing method embodiment. For the convenience of reading, the details of the foregoing method embodiment will not be repeated one by one in this device embodiment. However, it should be clear that the device in this embodiment can correspondingly implement all the contents of the foregoing method embodiment. In order to implement a load control method for a coal-fired unit, the device is applied to a load control device, and the load control device is arranged between the coal-fired unit and the molten salt thermal energy storage system. There is thermal energy functional coupling between the coal-fired unit and the molten salt thermal energy storage system, specifically as Figure 4 shown, the device includes:

[0126] A determination unit 41, which can be used to calculate the difference as a load command difference when detecting a difference between the load command of the automatic generation controller and the actual load of the current unit, and determine whether the molten salt thermal energy storage system participates in coordinated variable load control;

[0127] A judgment unit 42, which can be used to judge the operation mode of the molten salt thermal energy storage system based on the operation states of the cold salt pump and the hot salt pump in the molten salt thermal energy storage system if the determination unit 41 determines that the molten salt thermal energy storage system participates in coordinated variable load control;

[0128] A first control unit 43, which can be used to control the main steam extraction valve and the reheater extraction valve according to the operation mode of the molten salt thermal energy storage system judged by the judgment unit 42 to improve the variable load rate; wherein, the operation mode of the molten salt thermal energy storage system includes a heat storage mode and a heat release mode; wherein, the main steam extraction valve is arranged between the boiler of the coal-fired unit and the high-pressure cylinder of the coal-fired unit, and can be used to extract steam into the molten salt thermal energy storage system; the reheater extraction valve is arranged between the high-pressure cylinder and the intermediate-pressure cylinder of the coal-fired unit, and can be used to extract steam into the molten salt thermal energy storage system.

[0129] Further, in some embodiments, as Figure 5 shown, the judgment unit 42 can also be used to determine that the operation mode of the molten salt thermal energy storage system is the heat storage mode when it is determined that the cold salt pump is running, the molten salt flow rate at the outlet of the cold salt pump is greater than a first preset flow rate value, and the hot salt pump is not running; and, when it is determined that the cold salt pump is running and the molten salt flow rate at the outlet of the cold salt pump is greater than a first preset flow rate value, and the hot salt pump is running and the molten salt flow rate at the outlet of the hot salt pump is greater than a second preset flow rate value, determine that the operation mode of the molten salt thermal energy storage system is the heat release mode.

[0130] Further, in some embodiments, as Figure 5As shown, the first control unit 43 can also be used to control the main steam extraction valve to adjust the opening degree at a preset first rate according to the load command difference when the molten salt thermal energy storage system is in the thermal energy storage mode, and set the main steam extraction valve to the PID automatic adjustment mode with the adjusted opening degree after the adjustment; and, when the molten salt thermal energy storage system is in the thermal energy storage mode, control the reheat extraction valve to adjust the opening degree at a preset second rate according to the load command difference, and set the reheat extraction valve to the PID automatic adjustment mode with the adjusted opening degree after the adjustment.

[0131] Further, in some embodiments, as Figure 5 As shown, the first control unit 43 can also be used to control the main steam extraction valve to adjust the opening degree at a preset third rate according to the load command difference when the molten salt thermal energy storage system is in the heat release mode, and set the main steam extraction valve to the PID automatic adjustment mode with the adjusted opening degree after the adjustment; and, when the molten salt thermal energy storage system is in the heat release mode, control the hot extraction valve to adjust the opening degree at a preset fourth rate according to the load command difference, and set the reheat extraction valve to the PID automatic adjustment mode with the adjusted opening degree after the adjustment.

[0132] Further, in some embodiments, as Figure 5 As shown, the molten salt thermal energy storage system is further provided with a main steam superheater molten salt side inlet regulating valve, and the main steam superheater molten salt side inlet regulating valve is arranged between the main steam superheater of the salt thermal energy storage system and the cold salt tank of the salt thermal energy storage system;

[0133] The device further includes:

[0134] A second control unit 44, which can be used to control the main steam superheater molten salt side inlet regulating valve to adjust the opening degree at a preset fifth rate according to the load command difference obtained by the determination unit 41 when the molten salt thermal energy storage system is in the heat release mode, and set the main steam superheater molten salt side inlet regulating valve to the PID automatic adjustment mode with the adjusted opening degree after the adjustment;

[0135] A third control unit 45, which can be used to control the main steam superheater molten salt side inlet regulating valve to adjust the opening degree at a preset sixth rate according to the load command difference obtained by the determination unit 41 when the molten salt thermal energy storage system is in the thermal energy storage mode, and set the main steam superheater molten salt side inlet regulating valve to the PID automatic adjustment mode with the adjusted opening degree after the adjustment.

[0136] Further, in some embodiments, as Figure 5 As shown, the molten salt thermal energy storage system is further provided with a reheat superheater molten salt side inlet regulating valve, and the reheat superheater molten salt side inlet regulating valve is arranged between the reheat superheater of the salt thermal energy storage system and the cold salt tank of the salt thermal energy storage system;

[0137] The device further includes:

[0138] A fourth control unit 46, which can be used to control the regulating valve at the molten salt side inlet of the reheater superheater to adjust the opening degree according to the load command difference obtained by the determination unit 41 at a preset seventh rate when the molten salt thermal energy storage system is in the heat release mode, and set the regulating valve at the molten salt side inlet of the reheater superheater to the PID automatic regulation mode with the adjusted opening degree after the adjustment ends;

[0139] A fifth control unit 47, which can be used to control the regulating valve at the molten salt side inlet of the reheater superheater to adjust the opening degree according to the load command difference obtained by the determination unit 41 at a preset eighth rate when the molten salt thermal energy storage system is in the heat storage mode, and set the regulating valve at the molten salt side inlet of the reheater superheater to the PID automatic regulation mode with the adjusted opening degree after the adjustment ends.

[0140] Furthermore, in some embodiments, as Figure 5 shown, the molten salt thermal energy storage system is further provided with a high-temperature molten salt pump and a steam generator water supply valve; wherein, the high-temperature molten salt pump is arranged between the cold salt tank of the molten salt thermal energy storage system and the main steam superheater of the molten salt thermal energy storage system; the steam generator water supply valve is arranged between the steam generator of the molten salt thermal energy storage system and the feed water pump of the molten salt thermal energy storage system;

[0141] The device further includes:

[0142] A sixth control unit 48, which can be used to control the high-temperature molten salt pump to increase the frequency at a ninth rate according to the load command difference obtained by the determination unit 41 when the molten salt thermal energy storage system is in the heat release mode, and set the high-temperature molten salt pump to the PID automatic regulation mode after the frequency is increased to the target frequency;

[0143] A seventh control unit 49, which can be used to control the steam generator water supply valve to adjust the opening degree at a tenth rate according to the load command difference obtained by the determination unit 41 when the molten salt thermal energy storage system is in the heat release mode, and set the steam generator water supply valve to the PID automatic regulation mode after the adjustment.

[0144] Furthermore, in some embodiments, as Figure 5 shown, the device further includes:

[0145] An eighth control unit 50, which can be used to keep the frequency unchanged after the frequency of the high-temperature molten salt pump is adjusted by the sixth control unit 48 when the molten salt thermal energy storage system is in the heat release mode until the absolute value of the difference between the actual pressure of the steam supply header and the target pressure is less than the preset pressure difference;

[0146] The ninth control unit 51 can be used to keep the opening degree unchanged until the steam temperature at the outlet of the steam generator reaches a preset temperature range when the opening degree of the feed water valve of the steam generator is adjusted by the seventh control unit 49 when the molten salt thermal energy storage system is in the heat release mode.

[0147] Further, in some embodiments, as Figure 5 shown, the device further includes:

[0148] The tenth control unit 52 can be used to control the main steam extraction valve and the reheater extraction valve to abort the opening degree adjustment operation and set the main steam extraction valve and the reheater extraction valve to the PID automatic adjustment mode when the absolute value of the difference between the actual load of the unit and the load command obtained by the determination unit 41 of the automatic generation controller is less than a preset load deviation value.

[0149] To achieve the above object, according to another aspect of the present application, an embodiment of the present application further provides a storage medium, the storage medium includes a stored program, wherein when the program runs, it controls the device where the storage medium is located to execute the above-mentioned load control method of the coal-fired unit.

[0150] To achieve the above object, according to another aspect of the present application, an embodiment of the present application further provides a load control device for a coal-fired unit, the device includes a storage medium; and one or more processors, the storage medium is coupled to the processor, and the processor is configured to execute program instructions stored in the storage medium; when the program instructions run, they execute the above-mentioned load control method of the coal-fired unit.

[0151] The embodiment of the present application provides a load control method and device for a coal-fired unit, which are applied to load control equipment. The load control equipment is arranged between the coal-fired unit and the molten salt thermal energy storage system. There is a thermal energy function coupling between the coal-fired unit and the molten salt thermal energy storage system. Compared with the prior art, in the load control process of the coal-fired unit in the present application, by monitoring the difference between the load instruction and the current actual load of the unit in real time, it is judged whether the molten salt thermal energy storage system needs to participate. Once it is determined that participation is required, the load control equipment will precisely control the relevant valves according to the operating mode (heat storage or heat release) of the molten salt thermal energy storage system. This control process can directly and precisely control the valves in the coal-fired unit and its coupled molten salt thermal energy storage system, without the need to control other facilities in the molten salt thermal energy storage system and the coal-fired unit. Compared with setting through other operating facilities, directly controlling the valves in the control loop can directly and quickly respond to load changes and optimize the operation of the molten salt system, without waiting for the time required for the operation adjustment of each facility in the molten salt thermal energy storage system and the coal-fired unit. Therefore, the load change rate of the coal-fired unit can be significantly improved, and the problems of low load change rate and slow response in the prior art can be solved. In addition, by precisely controlling the main steam extraction valve and the reheater extraction valve, the present application realizes the precise control of the valves in the system loop, eliminating the control process of other facilities in the loop and simplifying the load control process. In addition, based on the method of the present application, the control is directly based on the valves, without the need to adjust the operating conditions of the facilities in the system. Therefore, during the process of stable load change, the frequent start-stop and large-scale adjustment processes of the corresponding equipment in the coal-fired unit and its molten salt thermal energy storage system are reduced, the equipment wear is reduced, and the service life of the equipment in the coal-fired unit and its coupled molten salt thermal energy storage system is prolonged.

[0152] The load control equipment of the coal-fired unit includes a processor and a memory. Each of the above units is stored in the memory as a program unit, and the processor executes the above program units stored in the memory to implement the corresponding functions.

[0153] The processor contains a kernel, and the kernel retrieves the corresponding program unit from the memory. One or more kernels can be set, and by adjusting the kernel parameters, a load control method for a coal-fired unit is implemented to solve the problems of complex control process and slow response speed of load change during the load control of the existing coal-fired unit.

[0154] The embodiment of the present application provides a load control equipment for a coal-fired unit. The equipment includes a storage medium; and one or more processors. The storage medium is coupled to the processor, and the processor is configured to execute the program instructions stored in the storage medium; when the program instructions run, they execute the load control method for the coal-fired unit described in any one of the foregoing.

[0155] An embodiment of the present application provides a storage medium, which includes a stored program. When the program runs, it controls the device where the storage medium is located to execute the load control method of the coal-fired unit described above.

[0156] The storage medium may include non-permanent memory in a computer-readable medium, in the form of random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. The memory includes at least one storage chip.

[0157] Based on the same inventive concept, an embodiment of the present application provides a device, which includes a processor, a memory, and a program stored on the memory and executable on the processor. When the processor executes the program, it implements the method in the foregoing embodiment. It should be noted here that the description of the above device embodiment is similar to the description of the above method embodiment and has similar beneficial effects to the method embodiment. For the technical details not disclosed in the embodiment of the computer-readable storage medium of the present application, please refer to the description of the method embodiment of the present application for understanding.

[0158] Based on the same inventive concept, the present application also provides a computer program product. When the computer program is executed by a processor, it implements the method in the foregoing embodiment. It should be noted here that the description of the above computer program product embodiment is similar to the description of the above method embodiment and has similar beneficial effects to the method embodiment. For the technical details not disclosed in the embodiment of the computer program product of the present application, please refer to the description of the method embodiment of the present application for understanding.

[0159] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0160] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate for implementation in the process Figure 1one or more processes and / or blocks Figure 1 means for the functions specified in one or more blocks

[0161] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured article including an instruction device that implements the processes Figure 1 one or more processes and / or blocks Figure 1 the functions specified in one or more blocks

[0162] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide for implementing the processes Figure 1 one or more processes and / or blocks Figure 1 the steps of the functions specified in one or more blocks

[0163] In a typical configuration, a computing device includes one or more processors (CPUs), an input / output interface, a network interface, and memory.

[0164] The memory may include non-permanent memory in computer-readable media, in the form of random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash memory (flash RAM). Memory is an example of computer-readable media.

[0165] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology for information storage. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media, such as modulated data signals and carrier waves.

[0166] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, commodity or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, commodity or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, commodity or device comprising the element.

[0167] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, system or computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0168] The above are only the embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A method for load control of a coal-fired unit, characterized in that, Applied to a load control device, which is arranged between a coal-fired unit and a molten salt thermal energy storage system, and there is thermal energy functional coupling between the coal-fired unit and the molten salt thermal energy storage system. The method includes: When a difference is detected between the load instruction of the automatic generation control device and the actual load of the current unit, calculate the difference as the load instruction difference, and determine whether the molten salt thermal energy storage system participates in coordinated load change control; If it is determined that the molten salt thermal energy storage system participates in coordinated load change control, then judge the operation mode of the molten salt thermal energy storage system based on the operation states of the cold salt pump and the hot salt pump in the molten salt thermal energy storage system; Control the main steam extraction valve and the reheat extraction valve according to the operation mode of the molten salt thermal energy storage system to increase the load change rate; wherein, the operation modes of the molten salt thermal energy storage system include a heat storage mode and a heat release mode; wherein, the main steam extraction valve is arranged between the boiler of the coal-fired unit and the high-pressure cylinder of the coal-fired unit, and is used to extract steam into the molten salt thermal energy storage system; the reheat extraction valve is arranged between the high-pressure cylinder and the intermediate-pressure cylinder of the coal-fired unit, and is used to extract steam into the molten salt thermal energy storage system.

2. The method according to claim 1, characterized in that, The judging the operation mode of the molten salt thermal energy storage system based on the operation states of the cold salt pump and the hot salt pump in the molten salt thermal energy storage system includes: When it is determined that the cold salt pump is operating, the molten salt flow rate at the outlet of the cold salt pump is greater than the first preset flow rate value, and the hot salt pump is not operating, determine that the operation mode of the molten salt thermal energy storage system is the heat storage mode; When it is determined that the cold salt pump is operating and the molten salt flow rate at the outlet of the cold salt pump is greater than the first preset flow rate value, and the hot salt pump is operating and the molten salt flow rate at the outlet of the hot salt pump is greater than the second preset flow rate value, determine that the operation mode of the molten salt thermal energy storage system is the heat release mode.

3. The method according to claim 2, wherein The controlling the main steam extraction valve and the reheat extraction valve according to the operation mode of the molten salt thermal energy storage system includes: When the molten salt thermal energy storage system is in the heat storage mode, control the main steam extraction valve to adjust the opening degree at a preset first rate according to the load instruction difference, and after the adjustment is completed, set the main steam extraction valve to the PID automatic adjustment mode with the adjusted opening degree; When the molten salt thermal energy storage system is in the heat storage mode, control the reheat extraction valve to adjust the opening degree at a preset second rate according to the load instruction difference, and after the adjustment is completed, set the reheat extraction valve to the PID automatic adjustment mode with the adjusted opening degree.

4. The method according to claim 2, wherein The controlling the main steam extraction valve and the reheat extraction valve according to the operation mode of the molten salt thermal energy storage system includes: When the molten salt thermal energy storage system is in the heat release mode, control the main steam extraction valve to adjust the opening degree at a preset third rate according to the load instruction difference, and after the adjustment is completed, set the main steam extraction valve to the PID automatic adjustment mode with the adjusted opening degree; When the molten salt thermal energy storage system is in the heat release mode, control the hot extraction valve to adjust the opening degree at a preset fourth rate according to the load instruction difference, and after the adjustment is completed, set the reheat extraction valve to the PID automatic adjustment mode with the adjusted opening degree.

5. The method according to claim 1, wherein The molten salt thermal energy storage system is also provided with a regulating valve for the molten salt side inlet of the main steam superheater, and the regulating valve for the molten salt side inlet of the main steam superheater is arranged between the main steam superheater of the salt thermal energy storage system and the cold salt tank of the salt thermal energy storage system; After controlling the main steam extraction valve and the reheater extraction valve according to the operating mode of the molten salt thermal energy storage system, the method further includes: When the molten salt thermal energy storage system is in the heat release mode, controlling the regulating valve for the molten salt side inlet of the main steam superheater to adjust the opening degree according to the load command difference at a preset fifth rate, and after the adjustment is completed, setting the regulating valve for the molten salt side inlet of the main steam superheater to the PID automatic regulation mode with the adjusted opening degree; When the molten salt thermal energy storage system is in the heat storage mode, controlling the regulating valve for the molten salt side inlet of the main steam superheater to adjust the opening degree according to the load command difference at a preset sixth rate, and after the adjustment is completed, setting the regulating valve for the molten salt side inlet of the main steam superheater to the PID automatic regulation mode with the adjusted opening degree.

6. The method according to claim 1, wherein The molten salt thermal energy storage system is also provided with a regulating valve for the molten salt side inlet of the reheater superheater, and the regulating valve for the molten salt side inlet of the reheater superheater is arranged between the reheater superheater of the salt thermal energy storage system and the cold salt tank of the salt thermal energy storage system; After controlling the main steam extraction valve and the reheater extraction valve according to the operating mode of the molten salt thermal energy storage system, the method further includes: When the molten salt thermal energy storage system is in the heat release mode, controlling the regulating valve for the molten salt side inlet of the reheater superheater to adjust the opening degree according to the load command difference at a preset seventh rate, and after the adjustment is completed, setting the regulating valve for the molten salt side inlet of the reheater superheater to the PID automatic regulation mode with the adjusted opening degree; When the molten salt thermal energy storage system is in the heat storage mode, controlling the regulating valve for the molten salt side inlet of the reheater superheater to adjust the opening degree according to the load command difference at a preset eighth rate, and after the adjustment is completed, setting the regulating valve for the molten salt side inlet of the reheater superheater to the PID automatic regulation mode with the adjusted opening degree.

7. The method according to claim 1, characterized in that, The molten salt thermal energy storage system is also provided with a high-temperature molten salt pump and a water supply valve for the steam generator; wherein, the high-temperature molten salt pump is arranged between the cold salt tank of the molten salt thermal energy storage system and the main steam superheater of the molten salt thermal energy storage system; the water supply valve for the steam generator is arranged between the steam generator of the molten salt thermal energy storage system and the feed water pump of the molten salt thermal energy storage system; After controlling the main steam extraction valve and the reheater extraction valve according to the operating mode of the molten salt thermal energy storage system, the method further includes: When the molten salt thermal energy storage system is in the heat release mode, controlling the high-temperature molten salt pump to increase the frequency according to the load command difference at a ninth rate, and after the frequency is increased to the target frequency, setting the high-temperature molten salt pump to the PID automatic regulation mode; When the molten salt thermal energy storage system is in the heat release mode, controlling the water supply valve for the steam generator to adjust the opening degree according to the load command difference at a tenth rate, and after the adjustment, setting the water supply valve for the steam generator to the PID automatic regulation mode.

8. The method according to claim 7, wherein The method further includes: When the molten salt thermal energy storage system is in the heat release mode, after the frequency of the high-temperature molten salt pump is adjusted, keep the frequency unchanged until the absolute value of the difference between the actual pressure of the steam supply header and the target pressure is less than the preset pressure difference; and / or When the molten salt thermal energy storage system is in the heat release mode, after the opening of the water supply valve of the steam generator is adjusted, keep the opening unchanged until the steam temperature at the outlet of the steam generator reaches the preset temperature range.

9. The method according to claim 1, wherein The method further includes: When the absolute value of the difference between the actual load of the unit and the load command of the automatic generation control device is less than the preset load deviation value, control the main steam extraction valve and the reheater extraction valve to stop performing the opening adjustment operation, and set the main steam extraction valve and the reheater extraction valve to the PID automatic adjustment mode.

10. A load control device for a coal-fired unit, characterized in that, Applied to a load control device, the load control device is arranged between a coal-fired unit and a molten salt thermal energy storage system, and there is a thermal energy function coupling between the coal-fired unit and the molten salt thermal energy storage system. The device includes: A determination unit, configured to calculate the difference as the load command difference when detecting a difference between the load command of the automatic generation control device and the current actual load of the unit, and determine whether the molten salt thermal energy storage system participates in coordinated load change control; A judgment unit, configured to, if it is determined that the molten salt thermal energy storage system participates in coordinated load change control, judge the operation mode of the molten salt thermal energy storage system based on the operation states of the cold salt pump and the hot salt pump in the molten salt thermal energy storage system; A first control unit, configured to control the main steam extraction valve and the reheater extraction valve according to the operation mode of the molten salt thermal energy storage system to increase the load change rate; wherein, the operation mode of the molten salt thermal energy storage system includes a heat storage mode and a heat release mode; wherein, the main steam extraction valve is arranged between the boiler of the coal-fired unit and the high-pressure cylinder of the coal-fired unit, and is used to extract steam into the molten salt thermal energy storage system; the reheater extraction valve is arranged between the high-pressure cylinder and the intermediate-pressure cylinder of the coal-fired unit, and is used to extract steam into the molten salt thermal energy storage system.

11. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program runs, control the device where the storage medium is located to execute the load control method of the coal-fired unit according to any one of claims 1-9.

12. A load control device for a coal-fired unit, characterized in that, The device includes a storage medium; and one or more processors, the storage medium is coupled with the processors, and the processors are configured to execute the program instructions stored in the storage medium; when the program instructions run, execute the load control method of the coal-fired unit according to any one of claims 1-9.

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