Starting and stopping method of fused salt steam generator system and electronic equipment

Abstract

The invention discloses a starting and stopping method of a fused salt steam generator system and electronic equipment, and relates to the technical field of fused salt energy storage. The method comprises the following steps: opening a water feeding adjusting valve of the deaerator, opening an inlet valve of the electric pump, and opening a recirculating valve of the electric pump; closing an electric pump to a steam generation system water inlet valve, closing a steam generation system water feeding main valve, and closing a steam generation system water feeding regulating valve; an electric pump is started to a steam generation system water inlet valve, a steam generation system water feeding adjusting valve is opened, a steam generation system emptying valve is opened, and a steam generation system steam outlet valve is closed; the steam generation system is pre-warmed; the molten salt system is pre-warmed through the molten salt system electric heat tracing device; and the cold salt pump outlet valve and the hot salt pump outlet valve are controlled to be closed, the cold salt pump recirculation valve is controlled to be opened, the cold salt pump is started, the cold salt pump outlet valve is started again, and salt is injected into the fused salt pipeline. The problems of high-temperature corrosion, solidification and the like in the starting process of the molten salt steam generator system are solved.

Description

Technical Field

[0001] The present application relates to the technical field of molten salt energy storage, and in particular to a method for starting and stopping a molten salt steam generator system and electronic equipment. Background Art

[0002] Molten salt is an excellent medium-to-high-temperature heat storage medium with low vapor pressure, good fluidity, and high heat storage temperature. Currently, the most widely used molten salt is solar salt (potassium nitrate + sodium nitrate). Its greatest advantages are its excellent thermal stability and low corrosiveness, but its disadvantage is its high freezing point of approximately 220°C. Molten salt exchanges heat with water in a steam generator, where the water is heated to superheated steam. This superheated steam drives a steam turbine, thereby converting thermal energy into electrical energy. When the water temperature entering the steam generator is below the freezing point of the molten salt, there is a risk of the molten salt solidifying, especially during the startup and shutdown phases of a molten salt steam generator system. Once solidified, molten salt is extremely difficult to handle and can render the generator useless. Therefore, preventing molten salt solidification during the startup and shutdown phases of a molten salt steam generator system is a pressing issue. Summary of the Invention

[0003] In view of the above problems, the present application provides a method for starting and stopping a molten salt steam generator system and electronic equipment.

[0004] To solve the above technical problems, this application proposes the following solutions:

[0005] In a first aspect, the present application provides a method for starting a molten salt steam generator system, the method being applied to a control device, the control device being used to control the molten salt steam generator system, the molten salt steam generator system comprising: a steam generating system and a molten salt system, the steam generating system comprising: a deaerator water supply regulating valve (1), a deaerator (2), an electric pump inlet valve (3), an electric pump starting recirculation valve (4), an electric pump to steam generating system water inlet valve (5), a steam generating system water supply main valve (6), a steam generating system water supply regulating valve (7), a steam drum (8), a starting circulation pump inlet valve (9), a starting circulation pump (10), a starting circulation pump inlet valve (11), a steam generating system emptying valve (12), a steam generating system steam outlet valve (13), and a deaerator steam inlet valve (21), the molten salt system comprising: a cold salt pump (15), a hot salt pump outlet valve (16), a cold salt pump outlet valve (17), and a cold salt pump recirculation valve (23);

[0006] The method comprises: opening a deaerator water supply regulating valve (1) to a first preset opening, opening an electric pump inlet valve (3), opening an electric pump start recirculation valve (4), and supplying water to the deaerator (2); closing an electric pump to a steam generation system water supply valve (5), closing a steam generation system water supply main valve (6), and closing a steam generation system water supply regulating valve (7), and isolating the steam generation system; opening an electric pump to a steam generation system water supply valve (5), opening a steam generation system water supply regulating valve (7) to a second preset opening, opening a steam generation system drain valve (12), and closing a steam generation system steam outlet valve (13), and supplying water to the deaerator (2); The steam drum (8) is filled with water; the deaerator steam inlet valve (21) is opened to a third preset opening, and after the start-up circulation pump inlet valve (9) is controlled to be opened, the start-up circulation pump (10) and the start-up circulation pump outlet valve (11) are controlled to be opened at the same time to preheat the steam generation system; the molten salt system is preheated by the molten salt system electric heating device; when the molten salt system and the steam generation system are preheated, the cold salt pump outlet valve (17) and the hot salt pump outlet valve (16) are controlled to be closed, the cold salt pump recirculation valve (23) is opened, the cold salt pump (15) is started, and the cold salt pump outlet valve (17) is opened to a fourth preset opening to inject salt into the molten salt pipeline.

[0007] In combination with the first aspect, in a possible implementation, the control device includes a PID controller, and before preheating the steam generation system, the method further includes: when the liquid level of the deaerator (2) is greater than a first preset liquid level threshold, controlling the opening of the deaerator upper water regulating valve (1) by the PID controller, thereby controlling the liquid level of the deaerator (2) to be the deaerator target liquid level; starting the water supply pump (27), and controlling the motor frequency of the water supply pump (27) to be the lowest stable operating frequency of the motor.

[0008] In combination with the first aspect, in another possible implementation, the method further includes: during the steam drum water filling process, when the temperature difference between the upper wall and the lower wall of the steam drum (8) is greater than a first preset steam drum wall temperature difference safety threshold, controlling the steam generation system water filling regulating valve (7) to reduce the first overrun opening according to a first preset time period.

[0009] In combination with the first aspect, in another possible implementation, the method further includes: when the liquid level of the steam drum (8) is greater than a second preset liquid level threshold, controlling the opening of the steam generation system water supply regulating valve (7) through a PID controller, thereby controlling the liquid level of the steam drum (8) to be the steam drum target liquid level.

[0010] In combination with the first aspect, in another possible implementation, preheating the steam generation system further includes: after the deaerator steam inlet valve (21) is opened, controlling the deaerator steam inlet valve (21) to increase the opening according to a second preset time period and a first opening increase value until the water temperature of the deaerator (2) is greater than the first preset temperature; when the water temperature of the deaerator (2) is greater than the first preset temperature, controlling the opening of the deaerator steam inlet valve (21) by a PID controller, thereby controlling the pressure of the deaerator (2) to be the deaerator target pressure.

[0011] In combination with the first aspect, in another possible implementation, the method further includes: when the difference between the outlet pressure and the inlet pressure of the starting circulation pump (10) is less than a first preset pressure difference threshold, stopping the starting circulation pump (10) and closing the starting circulation pump outlet valve (11) at the same time; after the starting circulation pump outlet valve (11) is closed, closing the starting circulation pump inlet valve (9).

[0012] In combination with the first aspect, in another possible implementation, the molten salt system further comprises: a hot salt pump (14), a superheater (18), and a hot salt pump recirculation valve (24). After the injection of salt into the molten salt pipeline is completed, the method further comprises: opening the hot salt pump recirculation valve (24), starting the hot salt pump (14), and controlling the motor frequency of the hot salt pump (14) to be the lowest stable operating frequency of the motor; controlling the opening of the hot salt pump outlet valve (16) according to a third preset time period to increase the inlet molten salt temperature of the superheater (18); When the inlet molten salt temperature of the superheater (18) is greater than a first preset preheating temperature threshold, the opening of the hot salt pump outlet valve (16) is controlled to be 100%, the cold salt pump outlet valve (17) is closed, the cold salt pump (15) is shut down, the steam generation system exhaust valve (12) is closed, and the steam generation system steam outlet valve (13) is opened; the motor speed of the hot salt pump (14) is controlled by a PID controller to control the outlet pipeline pressure of the superheater (18) to be the superheater target pressure, and the hot salt pump recirculation valve (24) is closed.

[0013] In combination with the first aspect, in another possible implementation, the method further includes: when the opening of the steam generation system water supply regulating valve (7) is greater than a fifth preset opening, opening the steam generation system water supply main valve (6); controlling the rotation speed of the water supply pump (27) by a PID controller to control the liquid level of the steam drum (8) to be at the steam drum target liquid level, and closing the electric pump to start the recirculation valve (4).

[0014] In a second aspect, the present application provides a method for shutting down a molten salt steam generator system, the method comprising: opening a hot salt pump recirculation valve (24) at a first preset rate, and opening an electric pump start-up recirculation valve (4) at a second preset rate; reducing a motor frequency of a hot salt pump (14) to a minimum stable operating frequency of the motor at a third preset rate, and shutting down the hot salt pump (14); reducing a motor frequency of a feed water pump (27) to a minimum stable operating frequency of the motor at a fourth preset rate, and shutting down the feed water pump (27); and closing a steam outlet valve (13) of a steam generating system.

[0015] In order to achieve the above-mentioned purpose, according to the third aspect of the present application, an electronic device is provided, which includes at least one processor, and at least one memory and a bus connected to the processor; wherein the processor and the memory communicate with each other through the bus; the processor is used to call the program instructions in the memory to execute the startup method of the molten salt steam generator system of the first aspect or the shutdown method of the molten salt steam generator system of the second aspect.

[0016] By means of the above technical solution, the technical solution provided by this application has at least the following advantages:

[0017] The startup method of the molten salt steam generator system of the present application is to use an electric heating device to heat the pipes, valves, pumps and other equipment of the molten salt system to above the melting point of the molten salt before injecting the molten salt, to ensure that the molten salt will not solidify due to the low temperature when it contacts the pipe, thereby avoiding local blockage. On this basis, the present application isolates the main molten salt pipeline by closing the cold salt pump outlet valve and the hot salt pump outlet valve to prevent the cold molten salt from directly entering the system that has not been fully preheated, or the hot salt pump from starting too early and causing pressure fluctuations. A closed-loop flow of "cold salt tank → cold salt pump → cold salt pump recirculation valve → cold salt tank" is established through the cold salt pump recirculation valve to maintain the minimum flow of molten salt, ensure the continuous flow of molten salt in the pipeline, and avoid static stagnation that causes the molten salt to cool and solidify. After the cold salt pump is running stably, slowly open the cold salt pump outlet valve to inject salt to further reduce the risk of solidification.

[0018] In addition, although the preheating of the steam generation system of the present application cannot directly prevent the molten salt from solidifying, it can ensure that the temperature on the steam side matches the molten salt side, avoiding local overcooling of the molten salt due to excessive temperature difference in the steam generator.

[0019] The present invention's method for shutting down a molten salt steam generator system prioritizes opening the hot salt pump recirculation valve before starting the electric pump to start the recirculation valve. This ensures the continuous flow of high-temperature molten salt within the molten salt steam generator system, avoiding the risk of local overheating or solidification. By gradually reducing the frequency, the present invention maintains a certain level of molten salt flow, ensuring a uniform temperature drop in the molten salt steam generator system and preventing damage to the equipment from thermal stress or solidification.

[0020] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0022] Figure 1 A schematic structural diagram of a control system of a molten salt steam generator system provided in an embodiment of the present application is shown;

[0023] Figure 2 A schematic structural diagram of an electronic device provided in an embodiment of the present application is shown;

[0024] Figure 3 A schematic structural diagram of a molten salt steam generator system provided in an embodiment of the present application is shown;

[0025] Figure 4 A schematic diagram of a process for starting a molten salt steam generator system provided in an embodiment of the present application is shown;

[0026] Figure 5 A schematic flow chart of a method for shutting down a molten salt steam generator system provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0027] The following describes exemplary embodiments of the present application in more detail with reference to the accompanying drawings. Although exemplary embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0028] In the embodiments of the present application, the terms "first" and "second" do not have a logical or temporal dependency, nor do they limit the quantity or execution order. It should also be understood that although the following description uses the terms "first", "second", etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another.

[0029] In the embodiments of the present application, the term "at least one" means one or more, and in the embodiments of the present application, the term "plurality" means two or more.

[0030] It should also be understood that the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting." Similarly, the phrase "if it is determined that..." or "if [stated condition or event] is detected" may be interpreted as "upon determining that..." or "in response to determining that..." or "upon detecting [stated condition or event]" or "in response to detecting [stated condition or event]," depending on the context.

[0031] The implementation of the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0032] Figure 1 This application provides a schematic diagram of the structure of a control system for a molten salt steam generator system. The control system 100 of the molten salt steam generator system includes a molten salt steam generator system 110 and a control device 120. The molten salt steam generator system 110 and the control device 120 communicate with each other via a network. For example, communication occurs via a network 130, which can be a wired connection such as a serial line or a Universal Asynchronous Receiver / Transmitter (UART), or a wireless connection such as a wireless signal.

[0033] Embodiments of the present application also provide a control device for a molten salt steam generator system. This control device may be the control device 120 in the control system 100 of the molten salt steam generator system described above, and is configured to execute a method for starting and shutting down the molten salt steam generator system. Alternatively, the control device may be an electronic device with data processing capabilities, or a functional module within such an electronic device, without limitation.

[0034] For example, the electronic device may be a server, which may be a single server, or a server cluster composed of multiple servers. For another example, the electronic device may be a mobile phone, a tablet computer, a desktop, a laptop, a handheld computer, a notebook computer, an ultra-mobile personal computer (UMPC), a netbook, as well as a cellular phone, a personal digital assistant (PDA), an augmented reality (AR), a virtual reality (VR) device and other terminal devices. For another example, the electronic device may also be a recording device, a video surveillance device and other devices. This application does not impose any special restrictions on the specific form of the electronic device.

[0035] The following example takes the control device in the control system of the molten salt steam generator system as an electronic device. Figure 2 As shown, Figure 2 This application provides a hardware structure of an electronic device 200.

[0036] like Figure 2 As shown, the electronic device 200 includes a processor 210 , a communication circuit 220 and a communication interface 230 .

[0037] Optionally, the electronic device 200 may further include a memory 240 , wherein the processor 210 , the memory 240 and the communication interface 230 may be connected via a communication line 220 .

[0038] The processor 210 may be a central processing unit (CPU), a general-purpose processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 210 may also be any other device with processing capabilities, such as a circuit, a device, or a software module, without limitation.

[0039] In one example, the processor 210 may include one or more CPUs, such as Figure 2 CPU0 and CPU1 in.

[0040] As an optional implementation, the electronic device 200 includes multiple processors. For example, in addition to the processor 210, it may also include a processor 270. The communication line 220 is used to transmit information between the various components included in the electronic device 200.

[0041] Communication interface 230 is used to communicate with other devices or other communication networks. Such other communication networks may be Ethernet, Radio Access Network (RAN), Wireless Local Area Network (WLAN), etc. Communication interface 230 may be a module, circuit, transceiver, or any other device capable of communication.

[0042] The memory 240 is used to store instructions, where the instructions may be computer programs.

[0043] Among them, the memory 240 can be a read-only memory (ROM) or other types of static storage devices that can store static information and / or instructions, or a random access memory (RAM) or other types of dynamic storage devices that can store information and / or instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), magnetic disk storage media or other magnetic storage devices, etc., without limitation.

[0044] It should be noted that the memory 240 can exist independently of the processor 210 or can be integrated with the processor 210. The memory 240 can be used to store instructions, program codes, or some data. The memory 240 can be located inside the electronic device 200 or outside the electronic device 200, without limitation.

[0045] The processor 210 is configured to execute instructions stored in the memory 240 to implement the communication method provided in the following embodiments of the present application. For example, when the electronic device 200 is a terminal or a chip in a terminal, the processor 210 may execute instructions stored in the memory 240 to implement the steps performed by the transmitting end in the following embodiments of the present application.

[0046] As an optional implementation, the electronic device 200 further includes an output device 250 and an input device 260. The output device 250 may be a device such as a display screen or a speaker that can output data from the electronic device 200 to a user. The input device 260 may be a device such as a keyboard, a mouse, a microphone, or a joystick that can input data to the electronic device 200.

[0047] It should be pointed out that Figure 2 The structure shown in the figure does not constitute a limitation on the electronic device, except Figure 2 In addition to the components shown, the electronic device may include more or fewer components than shown, or combine certain components, or arrange the components differently.

[0048] Figure 3 A structural diagram of a molten salt steam generator system is provided. The molten salt steam generator system includes a steam generation system and a molten salt system.

[0049] The steam generation system comprises: a deaerator water supply regulating valve (1), a deaerator (2), an electric pump inlet valve (3), an electric pump starting recirculation valve (4), an electric pump to steam generation system water supply valve (5), a steam generation system water supply main valve (6), a steam generation system water supply regulating valve (7), a steam drum (8), a starting circulation pump inlet valve (9), a starting circulation pump (10), a starting circulation pump inlet valve (11), a steam generation system drain valve (12), a steam generation system steam outlet valve (13), a deaerator steam inlet valve (21), and a feed water pump (27).

[0050] The deaerator feed water regulating valve (1) is used to regulate the feed water flow entering the deaerator to ensure the stability of the deaerator water level. The deaerator (2) is used for deoxidation and preheating. Deoxidation in the deaerator is to remove dissolved oxygen in the feed water by heating (steam or molten salt waste heat) to prevent oxygen corrosion of pipes and equipment. Preheating is to heat the feed water to a temperature close to saturation (such as 105-150℃) to improve the thermal efficiency of the system. The electric pump inlet valve (3) is used to control the water inlet of the feed water pump and can be isolated during maintenance. The electric pump start recirculation valve (4) is used to return part of the feed water to the deaerator during low load or startup to prevent the feed water pump from overheating and damage due to insufficient flow. The electric pump to steam generation system water inlet valve (5) is used to control the total flow of feed water from the feed water pump outlet into the steam generation system. The steam generation system water main valve (6) is a shut-off valve for the main feed water pipeline and is used for system isolation (such as emergency shutdown or maintenance). The steam generation system water supply regulating valve (7) is used to precisely regulate the feed water flow rate entering the drum and maintain a stable drum water level. The drum (8) is used for steam-water separation and buffer volume. Steam-water separation is to separate the steam-water mixture generated by the evaporator into saturated steam and water to ensure steam dryness. The buffer volume is to balance the fluctuations between the feed water and the evaporation rate and stabilize the system pressure. The starting circulation pump inlet valve (9) and the starting circulation pump outlet valve (11) are used to control the water inlet and outlet of the starting circulation pump. The starting circulation pump (10) is used to force water to circulate between the evaporator and the drum during system startup or low load to ensure uniform heating. The steam generation system drain valve (12) is used to exhaust (to exhaust air in the system during startup to prevent air lock) and drain (to drain water in the pipeline during shutdown to prevent freezing or corrosion). The steam generation system steam outlet valve (13) is used to control the flow of saturated steam from the drum outlet to the superheater or main steam pipeline. The deaerator steam inlet valve (21) is used to adjust the amount of heating steam entering the deaerator and control the pressure and temperature of the deaerator. The feed water pump (27) is used to pressurize the deoxygenated feed water to the required pressure of the steam drum (e.g., above 10 MPa).

[0051] The molten salt system comprises: a cold salt tank (25), a cold salt pump (15), a cold salt pump outlet valve (17), a cold salt pump recirculation valve (23), a hot salt pump outlet valve (16), a hot salt pump (14), a hot salt tank (26), a hot salt pump recirculation valve (24), a superheater (18), an evaporator (19), and a preheater (20).

[0052] The cold salt tank (25) is used to store low-temperature molten salt (usually about 290°C) and serves as the starting point of the molten salt cycle. It is also used to receive molten salt that has been cooled after heat exchange from the steam generator system, providing a stable supply of molten salt for the hot salt pump. The cold salt pump (15) is used to pressurize the low-temperature molten salt in the cold salt tank and transport it to a heat source such as a solar collector field or a nuclear reactor. The cold salt pump outlet valve (17) is used to control the flow direction of the molten salt at the outlet of the cold salt pump. The cold salt pump recirculation valve (23) is used to return part of the molten salt to the cold salt tank during low load or startup to prevent the cold salt pump from idling or overheating.

[0053] The hot salt pump outlet valve (16) is used to control the flow of high-temperature molten salt from the hot salt pump to the steam generator (superheater, evaporator, preheater). The hot salt pump (14) is used to pressurize and transport the high-temperature molten salt in the hot salt tank to the steam generator for heat exchange. The hot salt tank (26) is used to store high-temperature molten salt heated from a solar field or nuclear reactor. The hot salt pump recirculation valve (24) is similar to the cold salt pump recirculation valve (23). It allows some molten salt to flow back to the hot salt tank, protecting the hot salt pump from operating at low flow.

[0054] The superheater (18) uses high-temperature molten salt to further heat the saturated steam into superheated steam. The evaporator (19) is used to exchange heat between the high-temperature molten salt and water to generate saturated steam. The preheater (20) uses the waste heat of the molten salt to preheat the feed water to near the boiling point, thereby improving the thermal efficiency of the system.

[0055] The control system and application scenarios of the molten salt steam generator system described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field can know that with the evolution of the control system of the molten salt steam generator system and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0056] Next, a startup method of the molten salt steam generator system is described in detail with reference to the accompanying drawings. Figure 4 This is a flow chart of a method for starting a molten salt steam generator system provided in this application. Specifically, it includes the following steps:

[0057] Step 410: Open the deaerator water supply regulating valve (1), open the electric pump inlet valve (3), open the electric pump start recirculation valve (4), and supply water to the deaerator (2).

[0058] The water regulating valve on the deaerator can adjust the water inlet of the deaerator, and then control the water level inside the deaerator to be within the normal range. When the water level inside the deaerator is too high, it will cause water vapor to flow back, causing damage to the equipment in the molten salt steam generator system. When the water level inside the deaerator is too low, the deoxygenation effect of the deaerator decreases, increasing the risk of oxygen corrosion and may cause cavitation of the feed water pump. Feed water pump cavitation refers to the formation of bubbles caused by the vaporization of the liquid in the feed water pump due to the low pressure of the feed water pump. Feed water pump cavitation will damage the feed water pump impeller. The present application controls the feed water flow entering the deaerator by using the water regulating valve on the deaerator, which can avoid problems caused by excessively high or low water levels in the deaerator.

[0059] In one embodiment, the opening degree of the water regulating valve on the deaerator is controlled to be 30%, so that the water level inside the deaerator can be controlled to be maintained at 1 / 2 to 2 / 3 of the height of the deaerator.

[0060] After the deaerator is filled with water, the deaerator removes dissolved oxygen and other non-condensable gases in the feed water to prevent corrosion of the molten salt steam generator system.

[0061] After the deaerator is filled with water, the feedwater pump also needs to be filled with water. The electric pump inlet valve is located between the deaerator and the feedwater pump. Opening the electric pump inlet valve opens the water inlet passage from the deaerator to the feedwater pump, ensuring that the feedwater pump can properly absorb water. When the electric pump inlet valve is open, the feedwater pump can obtain sufficient static pressure head. The static pressure head ensures sufficient pressure at the feedwater pump inlet to prevent the feedwater pump from idling or cavitation.

[0062] During the startup phase, the electric pump recirculation valve is opened after water enters the feedwater pump to maintain the minimum safe flow rate of the feedwater pump and prevent overheating and cavitation. The electric pump recirculation valve ensures that the feedwater pump always operates above the rated flow rate by returning some of the feedwater from the feedwater pump outlet to the feedwater pump inlet or deaerator.

[0063] In summary, when the molten salt steam generator system is started, first open the deaerator water regulating valve to supply water to the deaerator. The deaerator removes dissolved oxygen and other non-condensable gases in the feed water to ensure that the water quality flowing in the molten salt steam generator system is qualified. Secondly, open the electric pump inlet valve to provide water for the feed pump. Finally, start the recirculation valve through the electric pump to adjust the flow of water in the feed pump to ensure the safe operation of the feed pump.

[0064] In addition, after filling the deaerator with water, the water level of the deaerator needs to be managed to ensure that the water level in the deaerator is stable and at the same time provide sufficient feed water flow for the molten salt steam generator system.

[0065] In one embodiment, a PID controller is used to control the opening of the deaerator's water supply regulating valve, thereby controlling the deaerator's liquid level. Specifically, when the deaerator's liquid level is low, the PID controller increases the opening of the deaerator's water supply regulating valve. When the deaerator's liquid level is high, the PID controller decreases the opening of the deaerator's water supply regulating valve, thereby maintaining the deaerator's liquid level at the target level.

[0066] Specifically, when the liquid level of the deaerator is greater than the first preset liquid level threshold, the PID controller first calculates the liquid level difference e(t) between the target liquid level and the actual liquid level of the deaerator, and then calculates the liquid level difference e(t) according to the first preset liquid level threshold. Control the opening u(t) of the deaerator water regulating valve, where K p is the proportional gain, used to adjust the response speed, K i is the integral gain, used to eliminate steady-state error, K d The differential gain is used to suppress overshoot and improve stability. By controlling the opening of the deaerator's upper water regulating valve through the PID controller, the deaerator's liquid level is controlled to the deaerator's target level, thus avoiding oscillation of the deaerator's upper water regulating valve caused by frequent adjustments.

[0067] While managing the deaerator water level, the feedwater pump is started and its motor frequency is controlled to its lowest stable operating frequency. This lowest stable motor frequency can be set as the initial operating frequency of the feedwater pump. In this embodiment of the present application, the feedwater pump can provide stable feedwater pressure and flow to support the operational requirements of the molten salt steam generator system.

[0068] Step 420: Isolate the steam generating system by closing the water inlet valve (5) from the electric pump to the steam generating system, closing the main water supply valve (6) of the steam generating system, and closing the water supply regulating valve (7) of the steam generating system.

[0069] During startup of the molten salt steam generator system, isolating the steam generation system ensures that it gradually generates the required pressure and temperature in a safe and controllable process, while also protecting the equipment within the system. Specifically, close the water inlet valve from the electric pump to the steam generation system, close the main water supply valve for the steam generation system, and close the water supply regulating valve for the steam generation system.

[0070] Closing the water inlet valve from the electric pump to the steam generation system can cut off the water supply channel from the feedwater pump to the steam generation system, preventing water flowing out of the feedwater pump outlet from impacting high-temperature equipment in the molten salt steam generator system during cold startup of the molten salt steam generator system. If there is already high-temperature molten salt in the steam generation system or molten salt system (for example, the molten salt has been preheated after the molten salt steam generator system is cold started), the sudden injection of low-temperature water may cause: 1. Thermal stress damage, that is, metal parts in the molten salt steam generator system may rupture due to sudden cooling and contraction. 2. Steam flash, that is, the instantaneous vaporization of water causes a sudden increase in pressure, damaging the pipes or equipment in the molten salt steam generator system. 3. Prevent overloading of the feedwater pump. If the steam generation system does not build pressure during the initial startup of the molten salt steam generator system, the feedwater pump may over-operate due to low outlet resistance.

[0071] Closing the steam generation system's main water supply valve completely isolates the main water supply pipe from the steam generation system. During the startup and preheating phase of the molten salt steam generator system (for example, when the molten salt is heating up or the steam generation system preheats the pipes), it is important to prevent water from accidentally entering high-temperature areas and ensure the molten salt system is dry. After the steam generation system's main water supply valve is closed, the recirculation valve is activated by an electric pump to gradually build pressure and temperature, preventing direct water injection into the molten salt system and achieving phased control.

[0072] Closing the steam generation system's water supply regulating valve disables the automatic water replenishment function and prevents misoperation. During startup, the molten salt steam generator system experiences instability (e.g., pressure and temperature fluctuations). If the steam generation system's water supply regulating valve is in automatic mode, it could suddenly open due to a misinterpretation of the signal, causing water to flood into high-temperature equipment. Therefore, close the steam generation system's water supply regulating valve during startup.

[0073] In summary, in this application, the feedwater pump is running but the water returns to the deaerator or water tank through the electric pump to start the recirculation valve, which can maintain the minimum flow protection of the feedwater pump. After the deaerator is fed with water and before the steam generation system is preheated, all the water inlet valves of the steam generation system are closed, and the pipes of the steam generation system are heated preferentially by molten salt or other heat sources to avoid hot and cold shocks. If these valves are not closed before the steam generation system is preheated, it may cause: 1. Water to enter the high-temperature molten salt pipe, thereby causing the risk of explosion, 2. The feedwater pump runs dry or cavitation, thereby causing damage to the impeller or bearings.

[0074] Step 430: Start the electric pump to the steam generation system water inlet valve (5), open the steam generation system water supply regulating valve (7), open the steam generation system drain valve (12), close the steam generation system steam outlet valve (13), and supply water to the steam drum (8).

[0075] In a molten salt steam generator system, the drum is used to separate saturated steam and water, ensuring that the dryness of the output steam meets the requirements, and storing a certain amount of water to buffer load fluctuations. During the startup process of the molten salt steam generator system, filling the drum with water is a critical stage. It is necessary to ensure that the drum is smoothly filled with water and fully exhausted, while avoiding thermal shock or pressure anomalies. Therefore, in an embodiment of the present application, the electric pump is turned on to the steam generation system water inlet valve, and the steam generation system water supply regulating valve is opened to the second preset opening, so that the water supply pump fills the drum with water at a certain rate. At the same time, the steam generation system drain valve is opened, and the steam generation system steam outlet valve is closed.

[0076] When filling the steam drum with water, opening the water inlet valve from the electric pump to the steam generation system can establish a water supply channel from the feed water pump to the steam generation system. Before step 430, the feed water pump only operates through the electric pump start-up recirculation valve, and in step 430, the feed water pump formally injects water into the main system. It should be noted that when opening the water inlet valve from the electric pump to the steam generation system, it is necessary to ensure that the feed water pump is operating at a stable frequency, and the electric pump start-up recirculation valve still needs to be partially opened to avoid the problem of overheating of the feed water pump due to too low flow rate. In addition, the water inlet valve from the electric pump to the steam generation system needs to be opened slowly to prevent water flow from impacting the pipeline.

[0077] Opening the water supply regulating valve of the steam generation system to the second preset opening can control the water supply flow of the drum, so that the water level of the drum rises at a safe rate (for example, 10% to 20% of the water level per minute). In an embodiment of the present application, the second preset opening can be set to 40% to 60%. If the second preset opening is set too small, it will cause the water supply of the drum to be too slow, thereby delaying the startup of the molten salt steam generator system. If the second preset opening is set too large, it may cause drum pressure fluctuations or thermal stress problems.

[0078] Opening the steam generation system drain valve can discharge the air and non-condensable gases in the molten salt steam generator system, preventing air accumulation from causing poor water flow or local overheating, and oxygen residue from accelerating metal oxidation.

[0079] Since pressure hasn't been established during the initial startup of the molten salt steam generator system, opening the steam generator system's outlet valve could prevent the drum from properly pressurizing or allow steam to carry moisture into the molten salt system's piping, causing water hammer or thermal stress cracking. Thermal stress cracking occurs when the upper drum wall (in contact with steam) is hotter than the lower wall (in contact with water), leading to uneven metal expansion and stress concentration. Therefore, closing the steam generator system's outlet valve during this phase also isolates the steam outlet, ensuring that the molten salt steam generator system does not leak steam or water during the water injection phase.

[0080] During the drum filling phase of a molten salt steam generator system, the temperature difference between the upper and lower drum walls is a key safety parameter. This temperature difference typically refers to the temperature difference between the top and bottom metal walls of the drum. Excessive temperature differences between the upper and lower drum walls can cause thermal stress cracking, and in severe cases, damage to the drum structure. To avoid this problem, this application employs a phased adjustment method to prevent the steam generation system's water filling regulating valve from operating too quickly, leading to drastic fluctuations in the drum water level.

[0081] Specifically, during the drum water filling process, when the temperature difference between the upper wall and the lower wall of the drum is greater than the first preset drum wall temperature difference safety threshold, the steam generation system water filling regulating valve is controlled to reduce the first override opening according to the first preset time period.

[0082] For example, the first preset time period is 8 minutes, the first override opening is 5%, and the first preset boiler wall temperature difference safety threshold is 50°C. In the initial state, the opening of the steam generation system water supply regulating valve is 50%. The temperature of the upper wall of the boiler is 120°C (steam heating), and the temperature of the lower wall is 60°C (cold water entering). At this time, the temperature difference between the upper and lower walls of the boiler is 60°C, which is greater than the first preset boiler wall temperature difference safety threshold of 50°C. The opening of the steam generation system water supply regulating valve is reduced from 50% to 45%. The timing starts when the opening of the steam generation system water supply regulating valve is reduced to 45%. If the temperature difference between the upper and lower walls of the boiler is still greater than 50°C within 8 minutes, the steam generation system water supply regulating valve will continue to be controlled to reduce the first override opening according to the first preset time period, that is, the opening of the steam generation system water supply regulating valve is reduced from 45% to 40%. If the temperature difference between the upper wall and the lower wall of the steam drum is less than or equal to 50°C within 8 minutes, stop adjusting the opening of the steam generation system water supply regulating valve and maintain the opening of the steam generation system water supply regulating valve at 45%.

[0083] When the liquid level of the boiler drum is greater than the second preset liquid level threshold, the second preset liquid level threshold can be set to 30% to 40%, indicating that the initial water filling stage of the molten salt steam generator system has been completed. At this time, the opening of the steam generation system water filling regulating valve is controlled by the PID controller, and then the liquid level of the boiler drum is controlled to be the target liquid level of the boiler drum to ensure stable operation of the boiler drum water level.

[0084] For example, if the second preset liquid level threshold is 30%, the steam generation system water supply regulating valve is open at 50%, the drum water level is 31%, and the drum target liquid level is 40%. At this point, the drum water level is greater than the second preset liquid level threshold, and the PID controller controls the opening of the steam generation system water supply regulating valve to maintain the drum water level at a stable level of 40% ± 2%.

[0085] It should be noted that the specific implementation method in which the PID controller controls the opening of the steam generation system water supply regulating valve, and then controls the liquid level of the steam drum to the target liquid level of the steam drum, is the same as the specific implementation method in which the PID controller controls the opening of the deaerator water supply regulating valve, and then controls the liquid level of the deaerator to the target liquid level of the deaerator, and will not be elaborated here.

[0086] Step 430 ensures that the drum water level rises steadily to a normal range (e.g., 30% to 50%). No air remains in the molten salt steam generator system, and pressure gradually builds. The feedwater pump and the molten salt steam generator system piping are not damaged by water hammer or cavitation.

[0087] Step 440: Open the deaerator steam inlet valve (21), control the start-up circulation pump inlet valve (9) to open, and simultaneously control the start-up circulation pump (10) and the start-up circulation pump outlet valve (11) to open, so as to preheat the steam generation system.

[0088] After completing step 430, preheat the steam generating system. First, open the deaerator steam inlet valve to the third preset opening to allow steam to enter the deaerator and increase the water temperature in the deaerator. The deaerator needs to heat the feed water to the saturation temperature in order to effectively remove gases such as dissolved oxygen (O2) and CO2 in the water to prevent corrosion of pipes and equipment in the molten salt steam generator system. If the water temperature in the deaerator is insufficient (such as during cold start), the deaerator's deoxidation effect is poor, which will lead to an increased risk of oxygen corrosion. In addition, the introduction of auxiliary steam can also help establish and maintain a slightly positive pressure environment in the deaerator, ensuring that the feed water in the deaerator continues to boil and promote gas escape. If the pressure in the deaerator is too low, the feed water in the deaerator cannot reach the saturation temperature, and the deoxidation efficiency decreases. If the pressure in the deaerator is too high, it may affect the safety of the molten salt steam generator system. In summary, the present application utilizes auxiliary steam to heat the feed water in the deaerator, which can ensure that the water temperature in the deaerator meets the deoxygenation requirements (usually the water temperature in the deaerator is ≥105°C) and avoid thermal shock or pressure fluctuations.

[0089] Specifically, after the deaerator steam inlet valve is opened, the valve is controlled to increase its opening according to a second preset time period and the first opening increment value until the deaerator water temperature exceeds the first preset temperature. When the deaerator water temperature exceeds the first preset temperature, the opening of the deaerator steam inlet valve is controlled by a PID controller, thereby controlling the deaerator pressure to the deaerator target pressure. When the deaerator water temperature exceeds the first preset temperature, it indicates that the heating demand of the deaerator has decreased. Prioritizing maintaining a stable pressure within the deaerator is necessary to prevent boiling or vaporization of the feed water within the deaerator.

[0090] For example, the second preset time period is 25 minutes, the first opening increment is 5%, the first preset temperature is 160°C, the deaerator target pressure is 1 MPa, and the third preset opening is 20%. Starting from the deaerator steam inlet valve opening of 20%, 25 minutes later, the deaerator air inlet valve opening is increased by the first opening increment of 5%, that is, the deaerator air inlet valve opening is increased from 20% to 25%. At this time, the deaerator water temperature is 150°C, which is still lower than the first preset temperature. Starting from the time when the deaerator air inlet valve opening is adjusted to 25%, the deaerator air inlet valve opening is increased from 25% to 30%. The deaerator water temperature is obtained. If the deaerator water temperature is still lower than the first preset temperature at this time, the deaerator steam inlet valve opening is continued to be increased according to the second preset time period and the first opening increment until the deaerator water temperature exceeds the first preset temperature of 160°C. Then, the opening of the deaerator steam inlet valve is controlled by the PID controller, thereby controlling the pressure of the deaerator to the deaerator target pressure of 1 MPa.

[0091] It should be noted that the specific implementation method of the PID controller controlling the opening of the deaerator steam inlet valve and then controlling the deaerator pressure to the deaerator target pressure is the same as the specific implementation method of the PID controller controlling the opening of the deaerator water supply regulating valve and then controlling the deaerator liquid level to the deaerator target liquid level, which will not be repeated here.

[0092] Furthermore, open the inlet valve of the starting circulation pump. After the inlet valve of the starting circulation pump is opened, open the starting circulation pump and the outlet valve of the starting circulation pump at the same time. This will allow water to establish a closed circulation between the deaerator, feed water pump, steam drum, and starting circulation pump, and slowly increase the water temperature of the feed water in the deaerator, feed water pump, steam drum, and starting circulation pump and the equipment pipe wall temperature.

[0093] During the startup of the molten salt steam generator system, slowly control the opening of the startup circulating pump inlet valve to 100% to establish the startup circulating pump inlet static head and ensure that the startup circulating pump chamber is filled with liquid. After confirming that the startup circulating pump inlet valve is fully open, start the startup circulating pump. If the startup circulating pump inlet valve is not fully open, starting the startup circulating pump may cause the startup circulating pump to inhale air and cause cavitation. In this application, the purpose of the startup circulating pump is to establish molten salt flow and ensure preheating and heat transfer of the molten salt steam generator system.

[0094] When the molten salt steam generator system reaches a stable state, the molten salt circulation can be taken over by the main pump. At this time, the starting circulation pump needs to be safely shut down. Specifically, determine whether the difference between the outlet pressure and the inlet pressure of the starting circulation pump is less than the first preset pressure difference threshold. If the difference between the outlet pressure and the inlet pressure of the starting circulation pump is less than the first preset pressure difference threshold, it means that the starting circulation pump is no longer doing effective work, that is, the molten salt steam generator system has reached a stable state, and the molten salt circulation is handed over to the main molten salt pump for maintenance. If the difference between the outlet pressure and the inlet pressure of the starting circulation pump is too low and the starting circulation pump continues to run, it will cause cavitation and waste energy. In order to prevent the starting circulation pump from idling or inefficient operation and causing damage to the equipment, the starting circulation pump is shut down when the difference between the outlet pressure and the inlet pressure of the starting circulation pump is less than the first preset pressure difference threshold.

[0095] At the same time, to avoid molten salt backflow or pressure fluctuations caused by the difference between the outlet pressure and the inlet pressure of the startup circulation pump, close the startup circulation pump outlet valve while shutting down the startup circulation pump. After closing the startup circulation pump outlet valve, close the startup circulation pump inlet valve to completely isolate the startup circulation pump for easy maintenance.

[0096] Step 450: Preheat the molten salt system through the molten salt system electric heating device.

[0097] In this embodiment, electric heating cables are installed on the exterior walls of various devices and pipelines in the molten salt system. The heating characteristics of these cables generate heat, maintaining the molten salt temperature within the devices and pipelines within the system within a preset range. For high-temperature environments like molten salt systems, MI mineral insulated cables are used for the heating cables.

[0098] The molten salt system equipment includes: a hot salt pump, a cold salt pump, a hot salt tank, a cold salt tank, a hot salt pump outlet valve, a cold salt pump outlet valve, a superheater, an evaporator, and a preheater. The molten salt system piping includes: the connecting pipe between the hot salt tank and the hot salt pump, the connecting pipe between the hot salt pump and the hot salt pump outlet valve, the connecting pipe between the hot salt pump outlet valve and the superheater, the connecting pipe between the superheater and the evaporator, the connecting pipe between the evaporator and the preheater, the connecting pipe between the preheater and the cold salt tank, the connecting pipe between the cold salt tank and the cold salt pump, the connecting pipe between the cold salt pump and the cold salt pump outlet valve, and the connecting pipe between the cold salt pump outlet valve and the superheater.

[0099] The molten salt system is preheated by an electric heating device before startup to ensure that the molten salt remains liquid throughout the process, avoiding molten salt solidification during startup that may cause blockage of the molten salt system or local overheating that may cause thermal shock, thereby ensuring the safe operation of the molten salt system.

[0100] Step 460: When the molten salt system and the steam generation system are preheated, the cold salt pump outlet valve (17) and the hot salt pump outlet valve (16) are controlled to be closed, the cold salt pump recirculation valve (23) is opened, the cold salt pump (15) is started, and then the cold salt pump outlet valve (17) is opened to inject salt into the molten salt pipeline.

[0101] The molten salt system preheating is complete when the wall temperatures of all pipes, valves, and equipment in the molten salt system are greater than the second preheating temperature threshold. Specifically, the wall temperatures of the hot salt pump, cold salt pump, hot salt tank, cold salt tank, hot salt pump outlet valve, cold salt pump outlet valve, superheater, evaporator, preheater, the connecting pipe between the hot salt tank and the hot salt pump, the connecting pipe between the hot salt pump and the hot salt pump outlet valve, the connecting pipe between the hot salt pump outlet valve and the superheater, the connecting pipe between the superheater and the evaporator, the connecting pipe between the evaporator and the preheater, the connecting pipe between the preheater and the cold salt tank, the connecting pipe between the cold salt tank and the cold salt pump, the connecting pipe between the cold salt pump and the cold salt pump outlet valve, and the connecting pipe between the cold salt pump outlet valve and the superheater are all greater than the second preheating temperature threshold. Alternatively, the second preheating temperature threshold can be 160°C.

[0102] Since the steam generation system drain valve is installed at a high point or end of the steam generation system, that is, the steam generation system drain valve is the final discharge point for condensed water and cold air within the steam generation system, the temperature meeting the standard here indicates that the steam generation system has been fully preheated. The outlet temperature of the steam generation system drain valve can directly reflect the overall preheating status of the steam generation system. Therefore, in this application, steam generation system preheating is completed when the outlet temperature of the steam generation system drain valve is greater than the first preheating temperature threshold. As an alternative, the first preheating temperature threshold can be 150°C.

[0103] When both the molten salt system and the steam generation system are preheated, it means that the entire molten salt steam generator system has the conditions for safe startup and stable operation.

[0104] Before officially operating the molten salt steam generator system, it is also necessary to close the cold salt pump outlet valve to isolate the cold salt pump from the downstream system of the cold salt pump (i.e., superheater, evaporator, preheater) to prevent the cold molten salt from impacting the high-temperature pipeline. Close the hot salt pump outlet valve to block the reflux of high-temperature molten salt and prevent hot salt (290°C+) from flowing back into the cold salt pump. Open the cold salt pump recirculation valve and establish a minimum flow protection loop to ensure that the cold salt pump always has 30% of the rated flow of the pump body. Then start the cold salt pump, increase the motor frequency of the cold salt pump to the minimum stable operating frequency of the motor and keep it running to establish the initial circulation flow.

[0105] After completing all the above operations, the molten salt steam generator system is ready to start operation. The cold salt pump outlet valve is opened to the fourth preset opening to inject salt into the molten salt pipeline. As an optional solution, the fourth preset opening can be 13%.

[0106] Furthermore, a second time period is preset. If the difference between the liquid level in the cold salt tank during the current period and the liquid level in the cold salt tank during the previous period is less than the first preset liquid level difference, the liquid level in the cold salt tank remains stable. At this point, the molten salt pipeline injection is complete. Alternatively, the second time period can be 15 minutes, and the first preset liquid level difference can be 3 mm.

[0107] After the molten salt pipeline is filled, open the hot salt pump recirculation valve to establish a minimum molten salt flow loop. This ensures a certain flow rate when the hot salt pump starts up, preventing the hot salt pump from running dry or at low flow, and preventing cavitation or overheating damage. Furthermore, after salt injection, the molten salt may not flow evenly within the pipeline. The hot salt pump recirculation valve can provide a temporary bypass. Then, start the hot salt pump and increase the motor frequency to its lowest stable operating frequency to ensure that the hot salt pump inlet is filled with molten salt and prevent air from being sucked out.

[0108] The temperature of the molten salt in the superheater directly affects the steam temperature. A sudden rise in the molten salt temperature can lead to steam overheating or water hammer risks. This is when cold steam in the pipe contacts the hot molten salt, causing instantaneous vaporization and pressure surges. Therefore, after the hot salt pump is started, the hot salt pump outlet valve is placed into closed-loop automatic control of the molten salt temperature at the superheater inlet. This involves using a PID controller to control the opening of the hot salt pump outlet valve, thereby controlling the molten salt flow rate entering the superheater and, consequently, the molten salt temperature at the superheater inlet.

[0109] When the molten salt temperature at the superheater inlet exceeds the first preset preheating temperature threshold, the molten salt is in a liquid state and its viscosity has decreased, allowing stable flow. The hot salt pump, pipelines, and valves have adapted to high-temperature conditions. The superheater's metal walls have reached a ductile state, with a small temperature difference from the molten salt, reducing the risk of thermal shock during heat exchange. At this point, the frequency of the hot salt pump can be increased, effectively starting the hot salt pump's main cycle. Specifically, exit the hot salt pump's outlet valve's closed-loop automatic temperature control, fully open the hot salt pump's outlet valve, close the cold salt pump's outlet valve, shut down the cold salt pump, close the steam generation system's drain valve, and open the steam generation system's steam outlet valve.

[0110] Fully opening the hot salt pump outlet valve minimizes flow resistance from the hot salt tank to the superheater and steam generator system, establishing the primary circulation path. This also prevents valve throttling, which could overload the hot salt pump or cause unstable molten salt flow. Closing the cold salt pump outlet valve and shutting down the cold salt pump switches the molten salt circulation path from the preheating mode (cold salt tank → electric heater → hot salt tank) to the primary circulation mode (hot salt tank → steam system → cold salt tank). During the preheating phase, the steam generation system drain valve is used to discharge condensate and air. After the primary circulation is started, closing the steam generation system drain valve maintains pressure in the molten salt steam generator system, preventing steam leakage and ensuring subsequent pressure increase. Furthermore, directly discharging high-temperature steam can reduce thermal efficiency. Closing the steam generation system drain valve also prevents energy waste. Opening the steam generation system outlet valve establishes a formal steam output path.

[0111] The superheater outlet pressure directly affects the steam saturation temperature (such as 1.0MPa corresponds to 180℃, and 4.0MPa corresponds to 250℃). Fluctuations in the outlet pressure of the superheater will cause changes in the heat transfer temperature difference, affecting the steam quality. Excessive superheater inlet pressure will also increase the back pressure of the hot salt pump, resulting in a decrease in flow rate. Excessive superheater inlet pressure may cause molten salt flash. Therefore, in this application, after the molten salt steam generator system enters the main circulation mode, the motor speed of the hot salt pump is controlled by the PID controller to control the outlet pipeline pressure of the superheater to the superheater target pressure. As an optional option, the superheater target pressure can be the current actual pressure value of the superheater. At the same time, close the hot salt pump recirculation valve to ensure that all flow enters the downstream pipeline (superheater) to avoid pressure fluctuations caused by bypass diversion.

[0112] After the molten salt steam generator system enters main circulation mode, relying solely on the fully open steam generation system water supply regulating valve can lead to insufficient flow capacity, resulting in a low steam generator water level and the risk of dry-boiling. This can also increase the feedwater pump outlet pressure and overload the feedwater pump. Therefore, when the opening of the steam generation system water supply regulating valve exceeds the fifth preset opening, the steam generation system water supply main valve is opened. As an option, the fifth preset opening can be 90%.

[0113] A stable drum level is a sign that steam output and feedwater flow are properly matched. Excessive drum level fluctuations can indicate issues such as abnormal molten salt heat exchange, feedwater pump failure, or sudden load changes. Therefore, to ensure a dynamic steam-feedwater balance, after the molten salt steam generator system enters the main circulation mode, a PID controller controls the feedwater pump speed to maintain the drum level at the target drum level.

[0114] During the initial startup phase, the feedwater pump must maintain a constant flow rate through the electric pump start-up recirculation valve to the deaerator to prevent cavitation and mechanical vibration. Once the primary circulation stabilizes, feedwater demand is determined by the actual steam generator evaporation rate. The electric pump start-up recirculation valve diverts the effective flow rate, reducing the amount of feedwater entering the steam drum and causing level control failure. It also wastes energy, as heated feedwater returns to the deaerator, increasing pump power consumption. Therefore, the electric pump start-up recirculation valve must be closed.

[0115] In summary, the startup method of the molten salt steam generator system of the present application can shorten the startup operation time of the system, avoid the problem of excessive temperature difference between the upper and lower walls of the steam drum during the water filling process, and the problem of condensation of the molten salt system during the startup process, thereby ensuring the safe operation of various equipment in the molten salt steam generator system.

[0116] Next, a method for shutting down a molten salt steam generator system will be described in detail with reference to the accompanying drawings. Figure 5 This is a flow chart of a method for shutting down a molten salt steam generator system provided in this application. Specifically, it includes the following steps:

[0117] Step 510: Open the hot salt pump recirculation valve (24), and start the electric pump to start the recirculation valve (4).

[0118] When shutting down a molten salt steam generator system, prioritizing the opening of the hot salt pump recirculation valve at a first preset rate ensures the continuous flow of high-temperature molten salt within the system, preventing the risk of localized overheating or solidification. Molten salt has a high freezing point, and a sudden stop in flow could clog piping or damage equipment within the system. Controlling the opening of the hot salt pump recirculation valve at a first preset rate (typically slower) allows for smooth system transitions and minimizes thermal shock damage to piping and valve seals.

[0119] After the hot salt pump recirculation valve is opened, the electric pump start-up recirculation valve is opened at a second preset rate. This is primarily used to balance pressure fluctuations during feedwater pump outages and prevent cavitation or excessive mechanical stress within the feedwater pump. If the electric pump start-up recirculation valve is opened first, molten salt from the low-temperature side may prematurely mix into the high-temperature circuit, causing a sudden temperature drop or thermal stress.

[0120] Step 520: Reduce the motor frequency of the hot salt pump (14) to the lowest stable operating frequency of the motor according to a preset rate, and stop the hot salt pump (14).

[0121] Molten salt easily solidifies at low temperatures. Sudden pump shutdown could cause a sudden drop in the molten salt flow rate within the molten salt steam generator system's pipelines, leading to localized cooling and blockage risks. Therefore, this application proposes a gradual frequency reduction (i.e., reducing the hot salt pump motor frequency to the motor's minimum stable operating frequency at a third preset rate) to maintain a certain level of molten salt flow, ensuring a uniform temperature drop in the molten salt steam generator system and preventing damage to the equipment from thermal stress or solidification.

[0122] Furthermore, shutting down a hot salt pump while it's running at high load could cause fluid inertia to impact pipes and valves, or damage the pump's bearings or inverter. Therefore, this application first reduces the pump's frequency to its lowest stable operating frequency, allowing the pump to enter a low-load state, reducing mechanical and electrical shock and extending its lifespan.

[0123] Step 530: Reduce the motor frequency of the water supply pump (27) to the lowest stable operating frequency of the motor, and stop the water supply pump (27).

[0124] The feed water pump is usually used to supply water to the steam generator or steam generator. If the pump is stopped directly, the high-speed flowing water will be suddenly blocked due to inertia, resulting in a water hammer effect (pressure shock wave), which will lead to pipeline vibration, valve damage and even pipe burst risk. Similar to the hot salt pump in step 520, directly cutting off the power and shutting down the feed water pump will also cause impact on the motor, bearings and mechanical seals, shortening the life of the feed water pump. Gradually reducing the frequency can allow the feed water pump to enter a low-load state, reducing mechanical wear and electrical stress. Therefore, the present application gradually reduces the frequency according to the fourth preset rate (usually slower) to allow the water flow rate to drop smoothly and avoid sudden changes in pressure.

[0125] Step 540: Close the steam outlet valve (13) of the steam generating system.

[0126] After shutting down the hot salt pump and the feedwater pump, high-temperature molten salt and a small amount of water / steam will still remain in the steam generation system. If the steam generation system outlet valve is closed prematurely, the residual heat will cause the pressure to continue to rise, which may exceed the design limit, triggering the safety valve to operate or equipment damage. Therefore, this application keeps the steam generation system outlet valve open when shutting down the hot salt pump and the feedwater pump, allowing the residual steam to be slowly discharged, naturally cooling and lowering the pressure. After the residual steam in the molten salt steam generator system is also discharged, the steam generation system outlet valve is closed.

[0127] It is understood that in order to implement the functions in the above embodiments, the computer device includes hardware structures and / or software modules corresponding to the execution of each function. It should be readily apparent to those skilled in the art that, in combination with the units and method steps of each example described in the embodiments disclosed in this application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in a hardware-driven manner or in a computer software-driven hardware manner depends on the specific application scenario and design constraints of the technical solution.

[0128] An embodiment of the present application provides a storage medium having a program stored thereon, which, when executed by a processor, implements the startup method of the molten salt steam generator system or the shutdown method of the molten salt steam generator system.

[0129] An embodiment of the present application provides a processor, which is configured to run a program, wherein when the program is run, the startup method of the molten salt steam generator system or the shutdown method of the molten salt steam generator system is executed.

[0130] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program having the following method steps for initialization: opening the deaerator water supply regulating valve (1) to a first preset opening, opening the electric pump inlet valve (3), opening the electric pump start recirculation valve (4), and supplying water to the deaerator (2); closing the steam generation system water supply main valve (6) by closing the electric pump to the steam generation system water supply valve (5), closing the steam generation system water supply regulating valve (7), and isolating the steam generation system; opening the steam generation system water supply regulating valve (5) by opening the electric pump to the steam generation system water supply regulating valve (7), opening the steam generation system water supply regulating valve (7) to a second preset opening, and opening the steam generation system drain valve ( 12), close the steam generation system steam outlet valve (13), and add water to the steam drum (8); open the deaerator steam inlet valve (21) to the third preset opening, control the start-up circulation pump inlet valve (9) to open, and simultaneously control the start-up circulation pump (10) and the start-up circulation pump outlet valve (11) to open, so as to preheat the steam generation system; preheat the molten salt system through the molten salt system electric heating device; when the molten salt system and the steam generation system are preheated, control the cold salt pump outlet valve (17) and the hot salt pump outlet valve (16) to close, open the cold salt pump recirculation valve (23), start the cold salt pump (15), and then open the cold salt pump outlet valve (17) to the fourth preset opening to inject salt into the molten salt pipeline.

[0131] Furthermore, when the liquid level of the deaerator (2) is greater than a first preset liquid level threshold, the opening of the deaerator upper water regulating valve (1) is controlled by a PID controller, thereby controlling the liquid level of the deaerator (2) to be the deaerator target liquid level; the water supply pump (27) is started, and the motor frequency of the water supply pump (27) is controlled to be the lowest stable operating frequency of the motor.

[0132] Furthermore, during the process of filling water into the steam drum, when the temperature difference between the upper wall and the lower wall of the steam drum (8) is greater than a first preset steam drum wall temperature difference safety threshold, the steam generation system filling water regulating valve (7) is controlled to reduce the first overrun opening according to a first preset time period.

[0133] Furthermore, when the liquid level of the drum (8) is greater than a second preset liquid level threshold, the opening of the steam generation system water supply regulating valve (7) is controlled by the PID controller, thereby controlling the liquid level of the drum (8) to be the drum target liquid level.

[0134] Furthermore, after the deaerator steam inlet valve (21) is opened, the deaerator steam inlet valve (21) is controlled to increase its opening according to a second preset time period and a first opening increase value until the water temperature of the deaerator (2) is greater than the first preset temperature; when the water temperature of the deaerator (2) is greater than the first preset temperature, the opening of the deaerator steam inlet valve (21) is controlled by a PID controller, thereby controlling the pressure of the deaerator (2) to be the deaerator target pressure.

[0135] Furthermore, when the difference between the outlet pressure and the inlet pressure of the starting circulation pump (10) is less than a first preset pressure difference threshold, the starting circulation pump (10) is stopped and the starting circulation pump outlet valve (11) is closed. After the starting circulation pump outlet valve (11) is closed, the starting circulation pump inlet valve (9) is closed.

[0136] Furthermore, the hot salt pump recirculation valve (24) is opened, the hot salt pump (14) is started, and the motor frequency of the hot salt pump (14) is controlled to be the lowest stable operating frequency of the motor; the opening of the hot salt pump outlet valve (16) is controlled according to a third preset time period to increase the inlet molten salt temperature of the superheater (18); when the inlet molten salt temperature of the superheater (18) is greater than the first preset preheating temperature threshold, the opening of the hot salt pump outlet valve (16) is controlled to be 100%, the cold salt pump outlet valve (17) is closed, the cold salt pump (15) is stopped, the steam generation system exhaust valve (12) is closed, and the steam generation system steam outlet valve (13) is opened; the motor speed of the hot salt pump (14) is controlled by a PID controller to control the outlet pipeline pressure of the superheater (18) to be the superheater target pressure, and the hot salt pump recirculation valve (24) is closed.

[0137] Furthermore, when the opening of the steam generation system water supply regulating valve (7) is greater than a fifth preset opening, the steam generation system water supply main valve (6) is opened; the rotation speed of the water supply pump (27) is controlled by the PID controller to control the liquid level of the steam drum (8) to the steam drum target liquid level, and the electric pump is turned off to start the recirculation valve (4).

[0138] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having the following method steps: opening a hot salt pump recirculation valve (24) at a first preset rate, opening an electric pump start-up recirculation valve (4) at a second preset rate; reducing a motor frequency of a hot salt pump (14) to a minimum stable operating frequency of the motor at a third preset rate, and shutting down the hot salt pump (14); reducing a motor frequency of a feed water pump (27) to a minimum stable operating frequency of the motor at a fourth preset rate, and shutting down the feed water pump (27); and closing a steam outlet valve (13) of a steam generating system.

[0139] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0140] In a typical configuration, the device includes one or more processors (CPUs), memory, and a bus. The device may also include input / output interfaces, network interfaces, and the like.

[0141] Memory may include non-permanent memory in a computer-readable medium, random access memory (RAM), and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory includes at least one memory chip. Memory is an example of a computer-readable medium.

[0142] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. 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 technology, 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 (transitory media), such as modulated data signals and carrier waves.

[0143] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0144] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0145] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A method for starting a molten salt steam generator system, characterized in that: The method is applied to a control device, wherein the control device is used to control a molten salt steam generator system, wherein the molten salt steam generator system comprises: a steam generating system and a molten salt system, wherein the steam generating system comprises: a deaerator water supply regulating valve (1), a deaerator (2), an electric pump inlet valve (3), an electric pump start recirculation valve (4), an electric pump to steam generating system water inlet valve (5), a steam generating system water supply main valve (6), a steam generating system water supply regulating valve (7), a steam drum (8), a start circulation pump inlet valve (9), a start circulation pump (10), a start circulation pump inlet valve (11), a steam generating system emptying valve (12), a steam generating system steam outlet valve (13), and a deaerator steam inlet valve (21); and wherein the molten salt system comprises: a cold salt pump (15), a hot salt pump outlet valve (16), a cold salt pump outlet valve (17), and a cold salt pump recirculation valve (23); The method comprises: Open the deaerator water supply regulating valve (1), open the electric pump inlet valve (3), open the electric pump start recirculation valve (4), and supply water to the deaerator (2); Close the water inlet valve (5) from the electric pump to the steam generation system, close the main water supply valve (6) of the steam generation system, close the water supply regulating valve (7) of the steam generation system, and isolate the steam generation system; Opening the water inlet valve (5) of the electric pump to the steam generation system, opening the water supply regulating valve (7) of the steam generation system, opening the steam generation system drain valve (12), closing the steam generation system steam outlet valve (13), and supplying water to the steam drum (8); Opening the deaerator steam inlet valve (21), controlling the start-up circulation pump inlet valve (9) to open, and simultaneously controlling the start-up circulation pump (10) and the start-up circulation pump outlet valve (11) to open, to preheat the steam generation system, and when the outlet temperature of the steam generation system exhaust valve (12) is greater than a first preheating temperature threshold, indicating that the preheating of the steam generation system is completed; preheating the molten salt system using an electric heating device for the molten salt system, and indicating that preheating of the molten salt system is complete when the wall temperatures of all pipes, valves, and equipment in the molten salt system are greater than a second preheating temperature threshold, where the second preheating temperature threshold is the melting point of the molten salt; When the molten salt system and the steam generation system are both preheated, the cold salt pump outlet valve (17) and the hot salt pump outlet valve (16) are controlled to be closed, the cold salt pump recirculation valve (23) is opened, the cold salt pump (15) is started, and then the cold salt pump outlet valve (17) is opened to inject salt into the molten salt pipeline.

2. The method according to claim 1, characterized in that The control device includes a PID controller. Before preheating the steam generation system, the method further includes: When the liquid level of the deaerator (2) is greater than a first preset liquid level threshold, the PID controller controls the opening of the deaerator upper water regulating valve (1), thereby controlling the liquid level of the deaerator (2) to be the deaerator target liquid level; The water supply pump (27) is started, and the motor frequency of the water supply pump (27) is controlled to be the lowest stable operating frequency of the motor.

3. The method according to claim 1, characterized in that The method further comprises: During the drum water filling process, when the temperature difference between the upper wall and the lower wall of the drum (8) is greater than a first preset drum wall temperature difference safety threshold, the steam generation system water filling regulating valve (7) is controlled to reduce a first overrun opening according to a first preset time period.

4. The method according to claim 1, wherein The method further comprises: When the liquid level of the steam drum (8) is greater than a second preset liquid level threshold, the opening of the steam generation system water supply regulating valve (7) is controlled by a PID controller, thereby controlling the liquid level of the steam drum (8) to be the steam drum target liquid level.

5. The method according to claim 1, characterized in that Preheating the steam generating system further comprises: After the deaerator steam inlet valve (21) is opened, controlling the deaerator steam inlet valve (21) to increase its opening according to a second preset time period and a first opening increment value until the water temperature of the deaerator (2) is greater than the first preset temperature; When the water temperature of the deaerator (2) is greater than a first preset temperature, the opening of the deaerator steam inlet valve (21) is controlled by a PID controller, thereby controlling the pressure of the deaerator (2) to be a deaerator target pressure.

6. The method according to claim 1, characterized in that The method further comprises: When the difference between the outlet pressure and the inlet pressure of the starting circulation pump (10) is less than a first preset pressure difference threshold, the starting circulation pump (10) is stopped and the starting circulation pump outlet valve (11) is closed. After the starting circulation pump outlet valve (11) is closed, the starting circulation pump inlet valve (9) is closed.

7. The method according to claim 1, characterized in that The molten salt system further comprises: a hot salt pump (14), a superheater (18), and a hot salt pump recirculation valve (24). After the molten salt pipeline is injected with salt, the method further comprises: Opening the hot salt pump recirculation valve (24), starting the hot salt pump (14), and controlling the motor frequency of the hot salt pump (14) to the lowest stable operating frequency of the motor; controlling the opening of the hot salt pump outlet valve (16) according to a third preset time period to increase the inlet molten salt temperature of the superheater (18); When the inlet molten salt temperature of the superheater (18) is greater than a first preset preheating temperature threshold, the opening of the hot salt pump outlet valve (16) is controlled to be 100%, the cold salt pump outlet valve (17) is closed, the cold salt pump (15) is stopped, the steam generation system drain valve (12) is closed, and the steam generation system steam outlet valve (13) is opened; The motor speed of the hot salt pump (14) is controlled by a PID controller to control the outlet pipeline pressure of the superheater (18) to the superheater target pressure, and the hot salt pump recirculation valve (24) is closed.

8. The method according to claim 7, characterized in that The method further comprises: When the opening of the steam generation system water supply regulating valve (7) is greater than a fifth preset opening, opening the steam generation system water supply main valve (6); The rotation speed of the water feed pump (27) is controlled by a PID controller to control the liquid level of the steam drum (8) to a target steam drum level, and the electric pump is closed to start the recirculation valve (4).

9. A method for shutting down a molten salt steam generator system, characterized in that: The method is applied to a control device for controlling a molten salt steam generator system as claimed in claims 1 to 8; The method comprises: Open the hot salt pump recirculation valve (24), and start the electric pump to start the recirculation valve (4); reducing the motor frequency of the hot salt pump (14) to the lowest stable operating frequency of the motor according to a preset rate, and shutting down the hot salt pump (14); when the hot salt pump (14) reduces the motor frequency according to the preset rate, it is ensured that the temperature in the molten salt steam generating system is greater than the melting point of the molten salt before the molten salt is emptied; reducing the motor frequency of the water supply pump (27) to the lowest stable operating frequency of the motor, and shutting down the water supply pump (27); Close the steam generating system steam outlet valve (13).

10. An electronic device, characterized in that: The device includes at least one processor, and at least one memory and a bus connected to the processor; wherein the processor and the memory communicate with each other through the bus; the processor is used to call program instructions in the memory to execute the startup method of the molten salt steam generator system as described in claims 1-8 or the shutdown method of the molten salt steam generator system as described in claim 9.

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