Salt dredging system and method based on mode switching and electronic equipment

Abstract

The invention provides a salt dredging system and method based on mode switching and electronic equipment, and relates to the technical field of salt dredging of a molten salt system.The salt dredging system comprises a salt dredging tank used for storing molten salt, a salt dredging working condition monitoring module used for monitoring the salt dredging working condition in a salt dredging pipeline, a purging module and a control module; the salt dredging tank is communicated with a system pipeline of the molten salt system; the control module is connected with the salt dredging working condition monitoring module and the purging module, and after a salt dredging instruction is received, the control module controls the purging module to be switched to different purging modes for purging according to the salt dredging working condition, so that efficient emptying of the molten salt system is achieved, the risk of pipeline crystallization is avoided, and the salt dredging safety and the automation level are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of salt shedding in a molten salt system, and in particular to a salt shedding system, method and electronic equipment based on mode switching. Background Art

[0002] To improve their deep peak-shaving capabilities, thermal power plants have added molten salt systems, primarily divided into heat storage molten salt systems and molten salt-steam SGS systems. The heat storage molten salt system primarily includes hot salt tanks, cold salt tanks, salt dilution tanks, hot salt pumps, cold salt pumps, tank bottom ventilation fans, and other equipment. The molten salt-steam SGS system primarily includes superheaters, evaporators, preheaters, steam drums, and start-up circulation pumps. These systems connect various devices into a sealed system via pipes and use ternary molten salt (KNO3, NaNO2, NaNO3) as the heat storage and release medium. The operating range is 150°C to 535°C, and the melting point of molten salt is 142°C. In the molten salt system, the molten salt must remain above its solidification temperature before it can flow through the pipes within these devices for heat storage and release cycles.

[0003] In the molten salt system coupled to the aforementioned thermal power plant, since the molten salt system operates discontinuously, it is necessary to prevent the molten salt from crystallizing during shutdown. Therefore, the system pipelines and equipment of the molten salt system utilize an electric heating system to maintain the temperature of the molten salt within the pipelines. However, the fit between the electric heating system and the pipe wall is easily affected by the expansion and contraction of the pipes during heat storage and release. If the heating effect of the electric heating system fails and residual molten salt remains in the pipelines and equipment, the low temperature of the pipe wall will inevitably cause the molten salt in the pipeline to solidify, affecting the system's re-commissioning. Furthermore, when an emergency failure occurs in the molten salt system and the molten salt needs to be drained as quickly as possible, there is no guarantee that the molten salt system will drain quickly, and it is impossible to predict the drainage of the molten salt within the molten salt system. This can easily lead to slow and incomplete drainage of the molten salt from the molten salt system, making it impossible to complete emergency response to the failure and causing the accident to escalate further.

[0004] In related technologies, molten salt systems typically use natural salt drainage. To ensure effective salt drainage, operators often keep the salt drain valve open for extended periods. However, if the salt drain pipe is connected to the salt drain tank and the valve is left open, the salt temperature inside the tank will be lost. Furthermore, the corrosive nature of the molten salt can cause corrosion and wear on the valve if left open for extended periods, compromising its sealing performance and potentially leading to leakage when the system is restarted. Summary of the Invention

[0005] The embodiments of the present invention provide a salt drainage system, method and electronic device based on mode switching to solve the problem that the molten salt system drains salt slowly and incompletely during discontinuous operation or emergency failure, which easily leads to solidification blockage and creates safety hazards.

[0006] In the first aspect, an embodiment of the present invention provides a salt diversion system based on mode switching, which is applied to a molten salt system, wherein the salt diversion system includes a salt diversion tank for storing molten salt, a salt diversion condition monitoring module for monitoring the salt diversion condition, a purge module and a control module; wherein the salt diversion tank is connected to the system pipeline of the molten salt system; the control module is respectively connected to the salt diversion condition monitoring module and the purge module; the purge module is used to purge the molten salt in the system pipeline to the salt diversion tank; the control module is used to control the purge module to switch to different purge modes for purge according to the salt diversion condition after receiving a salt diversion instruction.

[0007] In combination with the first aspect, in some embodiments, the control module includes a judgment submodule and a switching submodule; the judgment submodule is used to judge whether the salt shedding condition reaches a first preset condition or a second preset condition; during the salt shedding process, the salt shedding condition reaches the second preset condition after reaching the first preset condition; the switching submodule is used to control the purge module to switch to a corresponding purge mode according to the judgment result of the judgment submodule.

[0008] In combination with the first aspect, in some embodiments, the salt shedding system further includes a salt shedding pipe for connecting the salt shedding tank and the system pipe; the salt shedding operating conditions include the liquid level of the salt shedding tank, the flow rate of the salt shedding pipe, the temperature of the salt shedding pipe, and the conductivity at the system pipe; the first preset condition includes: the liquid level of the salt shedding tank remains unchanged and is maintained for a first preset time, the flow rate of the salt shedding pipe is lower than a first preset threshold and is maintained for a second preset time, and the difference between the temperature of the salt shedding pipe and the melting point of the molten salt is lower than a second preset threshold; the second preset condition includes: the flow rate of the salt shedding pipe is zero, the difference between the temperature of the salt shedding pipe and the electric heating preset temperature is lower than a third preset threshold, and the conductivity at the system pipe is lower than a fourth preset threshold and is maintained for a third preset time; wherein, the electric heating preset temperature is the set temperature of the electric heating in the molten salt system.

[0009] In combination with the first aspect, in some embodiments, the switching submodule is specifically used to: control the purge module to operate in a first purge mode before the salt-repelling operating condition reaches the first preset condition; when the salt-repelling operating condition reaches the first preset condition, control the purge module to switch from the first purge mode to the second purge mode; when the salt-repelling operating condition reaches the second preset condition, control the purge module to stop working; wherein, the purge module uses gas for purging, and the gas pressure in the second purge mode is greater than the gas pressure in the first purge mode.

[0010] In combination with the first aspect, in some embodiments, the gas temperature in the first purge mode and the second purge mode is not lower than the lowest operating temperature of the molten salt.

[0011] In combination with the first aspect, in some embodiments, the salt removal condition monitoring module includes: a liquid level monitoring device for monitoring the liquid level of the salt removal tank; a flow monitoring device for monitoring the flow of the salt removal pipeline; a temperature monitoring device for monitoring the temperature of the salt removal pipeline; and a conductivity monitoring device for monitoring the conductivity at the system pipeline.

[0012] In combination with the first aspect, in some embodiments, the purge module includes: a gas manufacturing device for providing purge gas; a pressure and temperature control device for controlling the gas pressure and gas temperature of the purge gas; and a purge execution device for controlling the gas pulse frequency of the purge gas.

[0013] In the second aspect, an embodiment of the present invention provides a salt shedding method based on mode switching, which is applied to a molten salt system containing a salt shedding system, wherein the salt shedding system includes a purge module, a salt shedding tank for storing molten salt, and a salt shedding condition monitoring module for monitoring the salt shedding condition; wherein the salt shedding tank is connected to the system pipeline of the molten salt system; the method includes: according to the salt shedding condition, controlling the purge module to switch to different purge modes to purge the molten salt in the system pipeline, and blowing the molten salt in the system pipeline to the salt shedding tank.

[0014] In combination with the second aspect, in some embodiments, according to the salt-repelling working condition, the purge module is controlled to switch to different purge modes to purge the molten salt in the system pipeline, including: before the salt-repelling working condition reaches a first preset condition, the purge module is controlled to operate in a first purge mode; when the salt-repelling working condition reaches the first preset condition, the purge module is controlled to switch from the first purge mode to the second purge mode; when the salt-repelling working condition reaches the second preset condition, the purge module is controlled to stop working; wherein, the salt-repelling working condition reaches the second preset condition after reaching the first preset condition; the purge module uses gas for purging, and the gas pressure in the second purge mode is greater than the gas pressure in the first purge mode.

[0015] In a third aspect, an embodiment of the present invention provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method in the second aspect or any possible implementation of the second aspect is implemented.

[0016] An embodiment of the present invention provides a salt shedding system, method and electronic equipment based on mode switching. The salt shedding system includes a salt shedding pipeline, a salt shedding tank for storing molten salt, a salt shedding condition monitoring module for monitoring the salt shedding condition in the salt shedding pipeline, a purge module and a control module. The salt shedding tank is connected to the system pipeline of the molten salt system through the salt shedding pipeline. The control module switches different purge modes according to the salt shedding condition in the molten salt system to purge the system pipeline of the molten salt system, thereby achieving efficient emptying of the molten salt system, avoiding the risk of pipeline crystallization, and improving the safety and automation level of salt shedding. It is suitable for shutdown maintenance and emergency fault handling of molten salt energy storage in thermal power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a schematic structural diagram of a salt-repelling system provided by one embodiment of the present invention;

[0018] Figure 2 1 is a schematic structural diagram of a salt-repelling system provided in another embodiment of the present invention;

[0019] Figure 3 is a schematic structural diagram of a control module provided by an embodiment of the present invention;

[0020] Figure 4 Schematic diagram of a salt-removing method according to an embodiment of the present invention;

[0021] Figure 5 is a schematic diagram of an electronic device provided by an embodiment of the present invention;

[0022] Among them, 100 represents the salt-dispersing system; 200 represents the molten salt system;

[0023] 110 represents a control module; 111 represents a judgment submodule; 112 represents a switching submodule;

[0024] 120 denotes a purge module; 121 denotes a gas production device; 122 denotes a pressure and temperature control device; 123 denotes a purge execution device;

[0025] 130 represents a salt-repelling condition monitoring module; 131 represents a liquid level monitoring device; 132 represents a flow monitoring device; 133 represents a temperature monitoring device; 134 represents a conductivity monitoring device;

[0026] 140 represents a salt drainage pipe of the salt drainage system;

[0027] 150 represents a salt drain tank;

[0028] 210 represents a system pipeline of a molten salt system;

[0029] 300 denotes an electronic device; 310 denotes a processor; 320 denotes a memory; and 330 denotes a computer program. DETAILED DESCRIPTION

[0030] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0031] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0032] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0033] As used in the present specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0034] In addition, in the description of the present specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0035] References to "one embodiment" or "some embodiments" in the present specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present invention. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in yet other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0036] Based on the problem in the background technology that the molten salt system discharges salt slowly and incompletely during discontinuous operation or emergency failure, which easily leads to solidification blockage and safety hazards, the embodiments of the present invention provide a salt drainage system, method and electronic equipment based on mode switching, which switches different purge modes according to the salt drainage working conditions in the molten salt system to purge the system pipelines of the molten salt system, thereby achieving efficient emptying of the molten salt system, avoiding the risk of pipeline crystallization, and improving the safety and automation level of salt drainage.

[0037] Figure 1 A schematic structural diagram of a mode switching-based salt-repelling system 100 provided in an embodiment of the present invention is shown. For ease of explanation, only the portion related to the embodiment of the present invention is shown, which is described in detail as follows:

[0038] like Figure 1 As shown, the mode-switching-based salt shedding system 100 in an embodiment of the present invention is used to shed salt from a molten salt system 200. The salt shedding system 100 includes a salt shedding tank 150 for storing molten salt, a salt shedding condition monitoring module 130 for monitoring the salt shedding condition, a purge module 120, and a control module 110; wherein, the salt shedding tank 150 is connected to the system pipeline 210 of the molten salt system 200 through a salt shedding pipe 140; the control module 110 is respectively connected to the salt shedding condition monitoring module 130 and the purge module 120; the purge module 120 is used to purge the molten salt in the system pipeline 210 to the salt shedding tank 150; the control module 110 is used to control the purge module 120 to switch to different purge modes for purge according to the salt shedding condition after receiving a salt shedding instruction.

[0039] In some embodiments, the salt drainage system 100 in the embodiment of the present invention may further include a salt drainage pipe 140 for connecting the salt drainage tank 150 and the system pipe 210. During the salt drainage process, the molten salt to be discharged in the system pipe 210 can be discharged into the salt drainage tank 150 through the salt drainage pipe 140.

[0040] In some embodiments, the molten salt system 200 has different forms of pipes such as horizontal pipes and vertical pipes, which together constitute the system pipe 210 of the molten salt system 200. The salt diversion system 100 may include one or more salt diversion pipes 140, which are connected to the salt diversion tank 150, that is, a salt diversion pipe 140 is connected to each lowest point position in the spatial position of the system pipe 210, and each salt diversion pipe 140 is configured with a salt diversion condition monitoring module 130. The salt diversion condition monitoring module 130 configured on each salt diversion pipe 140 is used to monitor the salt diversion condition, that is, each salt diversion pipe 140 corresponds to a salt diversion condition. Therefore, in some embodiments, several salt shedding pipes 140 correspond to several salt shedding conditions. If the salt shedding condition corresponding to at least one salt shedding pipe 140 does not meet the first preset condition, the first purge mode is continued to be performed; when the salt shedding conditions corresponding to several salt shedding pipes 140 all meet the first preset condition, the first purge mode is switched to the second purge mode; during the purge in the second purge mode, if the salt shedding condition corresponding to at least one salt shedding pipe 140 does not meet the second preset condition, the second purge mode is continued to be performed; when the salt shedding conditions corresponding to several salt shedding pipes 140 all meet the second preset condition, the purge work is stopped to achieve efficient emptying of the molten salt system 200.

[0041] The purge module 120 can be arranged at a high position in the system pipeline 210 to ensure that the purge gas it provides is purged from top to bottom. Accordingly, the salt drainage pipeline 140 can be arranged at a position lower than the purge module 120. In this way, the gas blown out by the purge module 120 can purge the molten salt to be discharged from the system pipeline 210 into the salt drainage tank 150 through at least one salt drainage pipeline 140; the arrangement of multiple salt drainage pipelines 140 connected to the salt drainage tank 150 can fully ensure the efficient discharge of the molten salt in the system pipeline 210.

[0042] In some embodiments, the molten salt in the molten salt system 200 is a ternary molten salt (KNO 3 , NaNO 2 , NaNO 3 ), with an operating temperature range of 150° C. to 535° C. and a melting point of 142° C.

[0043] In some embodiments, the salt drainage condition monitoring module 130 includes: a liquid level monitoring device 131 for monitoring the liquid level of the salt drainage tank 150; a flow rate monitoring device 132 for monitoring the flow rate of the salt drainage pipeline 140; a temperature monitoring device 133 for monitoring the temperature of the salt drainage pipeline 140; and a conductivity monitoring device 134 for monitoring the conductivity of the system pipeline 210. The combination of these multiple monitoring devices can achieve multi-dimensional judgment of the molten salt drainage status.

[0044] In one possible implementation, the salt shedding condition corresponds to the salt shedding condition monitoring module 130 , including the liquid level of the salt shedding tank 150 , the flow rate of the salt shedding pipeline 140 , the temperature of the salt shedding pipeline 140 , and the conductivity at the system pipeline 210 .

[0045] In one possible implementation, the liquid level monitoring device 131 is installed in the salt draining tank 150. By changing the liquid level in the salt draining tank 150, the salt draining situation of the molten salt system 200 can be judged intuitively but roughly. In a specific embodiment, the liquid level monitoring device 131 is installed on the top of the salt draining tank 150, and the salt draining process is judged by the trend of liquid level changes. In a specific embodiment, the background logic can be used to use a pulse signal to make a judgment. The pulse sending signal can be taken for 30 minutes. When there is no change in the liquid level within 30 minutes, it can be preliminarily judged that the molten salt is drained, and the next step is performed. If the liquid level changes within 30 minutes and it is judged that the molten salt is not drained, the next step is not performed, the timing is reset, and the timing is restarted for judgment.

[0046] like Figure 2 FIG. 1 is a schematic diagram of a structure of a salt-repelling system according to an embodiment of the present invention, which is described in detail as follows:

[0047] In one possible implementation, the flow monitoring device 132 is installed on the salt drainage pipe 140, and the flow is detected by a Doppler ultrasonic sensor. In the early stage of salt drainage of the molten salt system 200, the flow rate is relatively high. When it is close to emptying, the flow rate tends to zero. Therefore, the flow rate can be zero and maintained for a certain period of time as the basis for molten salt drainage. Specifically, since the salt drainage pipe 140 is mostly a vertical pipe, the flow monitoring device 132 can be axially arranged at the top, middle and bottom of the salt drainage pipe 140 to cover different flow layers and detect flow dynamics. The sensor inclination angle is ≤30° and the transmission frequency is 1-5MHz. Among them, the sensor can adopt a Doppler ultrasonic sensor to emit high-frequency ultrasonic waves (1-5MHz), capture the natural bubble / particle reflection signal in the molten salt, and calculate the local flow velocity by frequency shift. The Doppler probe inclination angle should be ≤30° to ensure that the sound beam effectively covers the flow core area. In a specific embodiment, salt drainage is considered complete when the flow rate remains close to zero, which can be 10 minutes. If the flow rate remains zero for 10 minutes, it can be preliminarily determined that the molten salt has been drained, and the next step can be performed. If the flow rate exceeds the set value within 10 minutes, the molten salt is not drained, the next step is not performed, the timer is reset, and the judgment is repeated again.

[0048] In one possible implementation, the temperature monitoring device 133 includes a thermocouple and a non-contact infrared thermometer arranged at the inlet end of the salt drainage pipe 140 to monitor the temperature change of the molten salt. Specifically, the temperature monitoring device 133 adopts a redundant design, including an armored thermocouple and a non-contact infrared thermometer to ensure the accuracy of temperature measurement. Specifically, in the process of heat storage and release, the molten salt needs to maintain a liquid state in the system and is always at a high temperature. A thermocouple is installed at the inlet end of the salt drainage pipe 140 to monitor temperature changes. When the salt is discharged, the temperature shows a downward trend. When the temperature drops to near the electric heating set temperature and remains stable, it can be used as a basis for judging whether the molten salt is drained. Among them, the temperature monitoring device 133 adopts a redundant design, that is, a high-temperature armored thermocouple + a non-contact infrared thermometer. The insertion depth of the thermocouple should be ≥10 times the diameter of the casing to ensure that the mainstream temperature is measured rather than the boundary layer.

[0049] In some embodiments, the change in molten salt flow rate during salt dilution may cause fluctuations in the convective heat transfer coefficient, so the temperature determination must be made after the flow determination.

[0050] In one possible implementation, the conductivity monitoring device 134 includes a sensor provided at the system pipe 210 of the molten salt system 200. For example, a conductivity sensor can be installed on the horizontal pipeline at the front end of the inlet of the salt drainage pipeline 140, and the principle of strong conductivity of liquid molten salt can be used to judge the salt drainage situation in the pipeline. In the initial salt drainage stage, the conductivity value measured by the sensor is high, and gradually decreases in the later stage. When the sensor conductivity is lower than the set threshold and lasts for a period of time, it can be judged that the molten salt is drained. A sensor is set in the horizontal pipe section at the front end of the inlet of the salt drainage pipeline 140. The conductivity of liquid molten salt is high, and the conductivity decreases when the residue decreases; when the conductivity is lower than the set threshold and lasts for a period of time, it is confirmed to be empty.

[0051] The conductivity of the liquid molten salt in the salt drainage pipe 140 is high at the initial stage of salt drainage, so the conductivity value is relatively high in the initial stage and gradually decreases as the salt drainage progresses.

[0052] The conductivity judgment boundary setting threshold can be set according to the different molten salts, and can be set to 10% of the conductivity of the molten salt.

[0053] The timer for determining salt removal completion when the conductivity is below the set threshold can be set to 10 minutes. If the conductivity remains below the set value within 10 minutes, it can be preliminarily determined that the molten salt has been completely removed, and the next step can be proceeded to. If the conductivity is above the set value within 10 minutes, the molten salt is not completely removed, and the next step is not proceeded to. The timer for this step is reset and the judgment is repeated again.

[0054] In some embodiments, the purge module 120 removes residual molten salt from the pipeline through gas purge technology, specifically including: a gas manufacturing device 121 for providing purge gas; a pressure and temperature control device 122 for controlling the gas pressure and gas temperature of the purge gas; and a purge execution device 123 for controlling the gas pulse frequency of the purge gas.

[0055] In one possible implementation, the purge gas provided by gas production device 121 is nitrogen. Specifically, gas production device 121 can utilize a cryogenic nitrogen generator to provide high-purity nitrogen, and be equipped with a gas storage tank to ensure sufficient supply. As the primary unit of purge module 120, gas production device 121 ensures both an adequate nitrogen supply and a purity level that meets regulatory requirements. This facilitates salt removal while ensuring nitrogen fills the pipeline, aiding in subsequent salt-side corrosion protection.

[0056] In one possible implementation, the pressure and temperature control device 122 includes a shell and tube heat exchanger, a built-in armored resistance wire with adjustable power, a stainless steel protective shell and a glass fiber insulation layer, which heats the gas to a temperature close to that of the molten salt. Temperature sensors and flow meters are set at the inlet and outlet, and a pressure relief valve is installed. The pressure and temperature control device 122 is used to heat the gas to a temperature close to that of the molten salt in the system to prevent cold gas from entering the system and causing the molten salt to cool and crystallize. The main component used for temperature control is a shell and tube heat exchanger, a built-in armored resistance wire with adjustable power, and a glass fiber insulation layer wrapped on the outer wall with a stainless steel protective shell. High-precision temperature sensors are set at the inlet and outlet of the heat exchanger to monitor the inlet and outlet gas temperatures in real time, and a flow meter is installed at the outlet to monitor the nitrogen flow at the outlet of the heat exchanger. A pressure relief valve is installed on the top of the heat exchanger to prevent overheating and expansion of the gas and cause overpressure.

[0057] In one possible implementation, the purge actuator 123 includes an electric valve and a pulse generator, and performs purge operations in different phases using different purge modes. Specifically, when the molten salt system 200 is operating normally, the electric purge valve is closed. When the molten salt system 200 is being purged, the electric purge valve is opened to purge the system pipeline 210 of the molten salt system 200.

[0058] In some embodiments, the control module 110 includes a determination submodule 111 and a switching submodule 112. Figure 3 The judgment submodule 111 is used to judge whether the salt shedding condition has reached the first preset condition or the second preset condition; during the salt shedding process, the salt shedding condition reaches the second preset condition after reaching the first preset condition; the switching submodule 112 is used to control the purge module 120 to switch to the corresponding purge mode according to the judgment result of the judgment submodule 111.

[0059] In some embodiments, the first preset condition includes: the liquid level of the salt drainage tank 150 remains unchanged and is maintained for a first preset time (such as 30 minutes), the flow rate of the salt drainage pipe 140 is lower than the first preset threshold and is maintained for a second preset time (such as 10 minutes), and the difference between the temperature of the salt drainage pipe 140 and the melting point of the molten salt is lower than the second preset threshold.

[0060] When judging the first preset condition, the temperature of the salt drainage pipe 140 must be stable. That is, the temperature must be stable within 10 minutes to preliminarily determine that the molten salt has been drained away, and then proceed to the next step. If the temperature fluctuates beyond the set value within 10 minutes, it is determined that the molten salt has not been drained away, and the next step is not proceeded to. The timer for this step is reset, and the judgment is repeated again.

[0061] In some embodiments, the second preset condition includes: the flow rate of the salt drainage pipe 140 is zero, the difference between the temperature of the salt drainage pipe 140 and the electric heating preset temperature is lower than a third preset threshold value (such as the temperature is stable at ±10°C of the electric heating preset temperature and is not lower than the melting point of the molten salt), and the conductivity of the system pipe 210 is lower than a fourth preset threshold value (such as 10% of the conductivity of liquid molten salt) and maintained for a third preset time (such as 5-10 minutes), and it is determined that the emptying is completed; wherein, the electric heating preset temperature is the set temperature of the electric heating in the molten salt system 200.

[0062] In one possible implementation, the second preset condition is that the conductivity of the system pipeline 210 is lower than 10% of the set threshold and lasts for 5-10 minutes.

[0063] When determining the second preset condition, the temperature of the salt drainage pipe 140 must also be stable. That is, if the temperature is stable within 10 minutes, it can be determined that the molten salt has been completely drained, and the next step can be performed. If the temperature fluctuates beyond the set value within 10 minutes, it is determined that the molten salt has not been completely drained, and the next step is not performed. The timer for this step is reset and the judgment is repeated again.

[0064] In some embodiments, the switching submodule 112 is specifically used to: before the salt-removing condition reaches the first preset condition, the molten salt mainly relies on gravity to drain, and the purge module 120 is controlled to use low-pressure gas to work in the first purge mode to assist in salt-removing; when the salt-removing condition reaches the first preset condition, the purge module 120 is controlled to switch from the first purge mode to the second purge mode, and high-pressure gas is used to impact pipe elbows, valves and other parts prone to residue, so as to completely remove the solid molten salt; when the salt-removing condition reaches the second preset condition, the purge module 120 is controlled to stop working; wherein, the purge module 120 uses gas for purging, and the gas pressure in the second purge mode is greater than the gas pressure in the first purge mode.

[0065] In some embodiments, the gas temperature in both the first and second purge modes is not lower than the minimum operating temperature of the molten salt. When the molten salt in the molten salt system 200 is a ternary molten salt (KNO3, NaNO2, NaNO3), its operating temperature range is 150°C to 535°C. Therefore, in some embodiments, the gas temperature in both the first and second purge modes is not lower than 150°C.

[0066] In some embodiments, the gas pulse frequency in both the first purge mode and the second purge mode is not less than a preset frequency value. In a specific embodiment, the preset frequency value may be 2 Hz. In other embodiments, the preset frequency value may also be other values.

[0067] In one possible implementation, the nitrogen pressure of the purge module 120 in the first purge mode is 0.3 MPa, and the temperature is heated to 150° C. The nitrogen pressure of the purge module 120 in the second purge mode is 1.5 MPa, and the pulse frequency is 2 Hz.

[0068] When the salt shedding system 100 according to the embodiment of the present invention is used to shed salt from the molten salt system 200, the working process includes:

[0069] After the molten salt system 200 is shut down, the molten salt system 200 is purged and desalted according to the received salt desalting instruction. At the initial stage of the purge, there is a lot of salt in the system and the salt desalting tank 150 is located at a low position. The molten salt can be discharged by itself by utilizing the height difference. The purge execution device 123 and the pressure and temperature control device 122 use low-pressure gas close to the salt temperature to purge the salt side pipeline (i.e., the first purge mode). When the salt desalting condition monitoring module 130 detects that the salt desalting condition reaches the first preset condition, it stops. At this time, the salt side pipeline of the molten salt system 200 is full of gas and enters the next stage of purge. High-pressure nitrogen close to the salt temperature is used for pulse purge (i.e., the second purge mode) to purge the residual molten salt at the pipeline elbow and valve. When the salt desalting condition monitoring module 130 detects that the salt desalting condition reaches the second preset condition, it is determined by comprehensive multi-parameter judgment that the salt desalting is completed.

[0070] The salt-repelling system 100 provided in an embodiment of the present invention can switch different purge modes to purge the system pipeline 210 under different salt-repelling working conditions. Before the first preset condition is reached, there is still a lot of molten salt in the system pipeline 210. The first purge mode is combined with the action of gravity to purge, thereby discharging most of the molten salt. When the first preset condition is reached, it means that the molten salt has been almost discharged, but there may still be some molten salt residues that cannot be discharged by gravity or low-pressure purge. Therefore, it is necessary to increase the purge pressure at this time to discharge the residual molten salt. When the second preset condition is reached, it shows that the residual molten salt has been basically emptied. Through this staged and mode-based purge design, the actual discharge of the molten salt can be determined based on the real-time monitoring data, and then the purge intensity can be reasonably adjusted according to the actual discharge situation, which can not only speed up the discharge of the molten salt but also ensure that the molten salt is exhausted, avoid the risk of pipeline crystallization, and extend the life of the molten salt system.

[0071] Figure 4 A schematic diagram of the steps of a salt-removing method based on mode switching provided by an embodiment of the present invention is shown. For ease of explanation, only the part related to the embodiment of the present invention is shown, which is detailed as follows:

[0072] The mode switching-based salt diversion method in an embodiment of the present invention is applied to a salt diversion system 100, which includes a salt diversion pipeline 140, a purge module 120, a salt diversion tank 150 for storing molten salt, and a salt diversion condition monitoring module 130 for monitoring the salt diversion condition in the salt diversion pipeline 140; wherein, the salt diversion tank 150 is connected to the system pipeline 210 of the molten salt system 200 through the salt diversion pipeline 140; the method includes: according to the salt diversion condition, controlling the purge module 120 to switch to different purge modes to purge the molten salt in the system pipeline 210, and blowing the molten salt in the system pipeline 210 to the salt diversion tank 150.

[0073] In some embodiments, according to the salt-repelling working condition, the purge module 120 is controlled to switch to different purge modes to purge the molten salt in the system pipeline 210, including: before the salt-repelling working condition reaches the first preset condition, the purge module 120 is controlled to work in the first purge mode; when the salt-repelling working condition reaches the first preset condition, the purge module 120 is controlled to switch from the first purge mode to the second purge mode; when the salt-repelling working condition reaches the second preset condition, the purge module 120 is controlled to stop working; wherein, the salt-repelling working condition reaches the first preset condition first and then reaches the second preset condition; the purge module 120 uses gas for purging, and the gas pressure in the second purge mode is greater than the gas pressure in the first purge mode.

[0074] In the above embodiment, when the salt removal is started (i.e., after receiving the salt removal instruction), the purge module 120 is turned on, and low-pressure purge is initially used to assist the self-drainage of the molten salt, that is, the first purge mode is used for operation. Nitrogen is filled into the pipeline, which not only promotes salt removal, but also provides assistance for the salt side corrosion protection of the pipeline in the later stage. When the first preset condition is reached, it is switched to high-voltage pulse purge, that is, the second purge mode is used to work to remove stubborn residues. The conductivity monitoring data is used as the final criterion, and the purge is terminated after confirming that the molten salt in the pipeline is completely emptied.

[0075] A specific embodiment is given below for introduction:

[0076] After completing its daytime peak-shaving mission, a thermal power plant needed to shut down its molten salt energy storage system for maintenance. To prevent residual molten salt in the pipeline from crystallizing and clogging due to a drop in temperature, and to address potential emergency failure risks, the power plant activated the aforementioned salt drainage system 100 to perform a rapid and thorough salt drainage process:

[0077] 1. System startup and initial salt removal:

[0078] Triggering condition: After the shutdown command of the molten salt system 200 is issued, the central control unit automatically starts the salt drainage program.

[0079] Low-pressure nitrogen purge assistance (first purge mode): the purge module 120 is turned on, and low-pressure nitrogen (0.3 MPa, heated to 150° C.) is injected into the pipeline to assist the molten salt in draining to the salt draining tank 150 by gravity.

[0080] Real-time monitoring: Liquid level monitoring shows that the liquid level in the salt separation tank 150 is rising rapidly, the flow sensor detects a high flow value, and the temperature sensor shows that the molten salt inlet temperature is gradually decreasing from 400°C.

[0081] 2. Transition to high-voltage pulse purging

[0082] Criteria conversion: When the liquid level monitoring data of the salt drain tank 150 is stable (such as no change within 30 minutes), the flow rate drops to near zero, and the temperature is close to the melting point of molten salt (142°C), the system automatically switches to the high-pressure pulse purge mode (i.e., the second purge mode).

[0083] High-pressure pulse removal (second purge mode): Nitrogen pressure is increased to 1.5 MPa, and a pulse generator pulses at a 2 Hz frequency at pipe elbows, valves, and other areas prone to blockage. The conductivity sensor provides real-time feedback, gradually decreasing the conductivity from an initial 3000 μS / cm to below 300 μS / cm.

[0084] 3. Final Confirmation and Termination

[0085] Multi-parameter comprehensive judgment: the conductivity is lower than the threshold (such as 300μS / cm) for 10 minutes, the temperature is stable at ±10℃ of the set temperature of the electric heating, and the flow rate is zero.

[0086] System shutdown: The central control unit confirms that the salt removal is completed and closes the purge module 120 and the salt removal valve.

[0087] It should be understood that the order of execution of the steps in the above embodiments does not necessarily mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0088] Figure 5 Schematic diagram of an electronic device provided by an embodiment of the present invention. Figure 5 As shown, the electronic device 300 of this embodiment includes a processor 310 and a memory 320. The memory 320 stores a computer program 330. When the processor 310 executes the computer program 330, the steps of the above-described method embodiments are implemented. Alternatively, when the processor 310 executes the computer program 330, the functions of the modules / units in the above-described device embodiments are implemented.

[0089] For example, the computer program 330 may be divided into one or more modules / units, which are stored in the memory 320 and executed by the processor 310 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, and the instruction segments are used to describe the execution process of the computer program 330 in the electronic device 300.

[0090] The electronic device 300 may include, but is not limited to, a processor 310 and a memory 320. Those skilled in the art will appreciate that Figure 5 It is only an example of the electronic device 300 and does not constitute a limitation of the electronic device 300. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the electronic device 300 may also include input and output devices, network access devices, buses, etc.

[0091] For the sake of convenience and brevity, the division of the above functional modules / units is only used as an example. In actual applications, the above functions can be assigned to different functional modules / units as needed. The above modules / units can be implemented in the form of hardware, software, or a combination of hardware and software.

[0092] In the above embodiments, the descriptions of each embodiment have their own focus. For parts not described or recorded in detail in one embodiment, please refer to the relevant descriptions of other embodiments. Unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features of different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0093] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A salt-removing system based on mode switching, characterized in that: Applied to a molten salt system, the salt diversion system includes a salt diversion tank for storing molten salt, a salt diversion condition monitoring module for monitoring the salt diversion condition, a purge module, and a control module; wherein the salt diversion tank is connected to a system pipeline of the molten salt system; the control module is connected to the salt diversion condition monitoring module and the purge module respectively; The purge module is used to purge the molten salt in the system pipeline to the salt drainage tank; The control module is used to control the purge module to switch to different purge modes for purge according to the salt removal working condition after receiving the salt removal instruction.

2. A salt-repelling system based on mode switching according to claim 1, characterized in that: The control module includes a judgment submodule and a switching submodule; The judgment submodule is used to judge whether the salt-removing working condition meets the first preset condition or the second preset condition; During the salt shedding process, the salt shedding working condition reaches the second preset condition after reaching the first preset condition; The switching submodule is used to control the purge module to switch to a corresponding purge mode according to the judgment result of the judgment submodule.

3. A salt-repelling system based on mode switching according to claim 2, characterized in that: The salt drainage system further includes a salt drainage pipeline for connecting the salt drainage tank and the system pipeline; the salt drainage working conditions include the liquid level of the salt drainage tank, the flow rate of the salt drainage pipeline, the temperature of the salt drainage pipeline, and the conductivity of the system pipeline; The first preset condition includes: the liquid level of the salt drainage tank remains unchanged and is maintained for a first preset time, the flow rate of the salt drainage pipeline is lower than a first preset threshold and is maintained for a second preset time, and the difference between the temperature of the salt drainage pipeline and the melting point of the molten salt is lower than a second preset threshold; The second preset condition includes: the flow rate of the salt drainage pipeline is zero, the difference between the temperature of the salt drainage pipeline and the preset temperature of the electric heating is lower than a third preset threshold, and the conductivity at the system pipeline is lower than a fourth preset threshold and maintained for a third preset time; wherein, the preset temperature of the electric heating is the set temperature of the electric heating in the molten salt system.

4. A salt-repelling system based on mode switching according to claim 2, characterized in that: The switching submodule is specifically used for: Before the salt-removing working condition reaches the first preset condition, controlling the purge module to operate in a first purge mode; When the salt-removing working condition reaches a first preset condition, controlling the purge module to switch from the first purge mode to the second purge mode; When the salt-removing working condition reaches a second preset condition, controlling the purge module to stop working; The purge module uses gas for purge, and the gas pressure in the second purge mode is greater than the gas pressure in the first purge mode.

5. A salt-repelling system based on mode switching according to claim 4, characterized in that: The gas temperature in the first purge mode and the second purge mode is not lower than the lowest operating temperature of the molten salt.

6. The salt-repelling system based on mode switching according to claim 3, characterized in that: The salt-removing condition monitoring module includes: A liquid level monitoring device, used to monitor the liquid level of the salt drain tank; A flow monitoring device, used to monitor the flow of the salt diversion pipeline; A temperature monitoring device, used to monitor the temperature of the salt diversion pipeline; The conductivity monitoring device is used to monitor the conductivity of the system pipeline.

7. The salt-repelling system based on mode switching according to claim 1, characterized in that: The purge module comprises: a gas production device for providing purge gas; a pressure and temperature control device for controlling the gas pressure and gas temperature of the purge gas; The purge execution device is used to control the gas pulse frequency of the purge gas.

8. A salt-removing method based on mode switching, characterized in that: A molten salt system including a salt diversion system is applied, wherein the salt diversion system includes a purge module, a salt diversion tank for storing molten salt, and a salt diversion condition monitoring module for monitoring the salt diversion condition; wherein the salt diversion tank is connected to a system pipeline of the molten salt system; and the method includes: When the salt removal instruction is received, the purge module is controlled to switch to different purge modes according to the salt removal working condition to purge the molten salt in the system pipeline, and the molten salt in the system pipeline is purged into the salt removal tank.

9. The salt-reducing method based on mode switching according to claim 8, characterized in that: The controlling the purge module to switch to different purge modes to purge the molten salt in the system pipeline according to the salt-removing working condition includes: Before the salt-removing working condition reaches a first preset condition, controlling the purge module to operate in a first purge mode; When the salt-removing working condition reaches a first preset condition, controlling the purge module to switch from the first purge mode to the second purge mode; When the salt-removing working condition reaches a second preset condition, controlling the purge module to stop working; Among them, the salt-removing working condition reaches the second preset condition after reaching the first preset condition; the purge module uses gas for purging, and the gas pressure in the second purge mode is greater than the gas pressure in the first purge mode.

10. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method according to any one of claims 8 or 9 is implemented.

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