A steam generator internal leakage grading early warning system

Abstract

The application relates to the technical field of steam generation, in particular to an internal leakage grading early warning system for a steam generation device, which comprises a control device and a steam generation device, wherein the control device is used for acquiring first moisture concentration data of a vaporizer loop molten salt outlet in real time, and based on the first moisture concentration data of each sampling moment and an early leakage early warning strategy, when early leakage exists, acquiring first temperature data of the vaporizer loop molten salt outlet and second temperature data of a mixed salt tank outlet in real time; based on the first temperature data, the second temperature data and the first moisture concentration data of each sampling moment after early leakage, and a leakage development early warning strategy, when leakage development exists, sending a first control instruction to a high-temperature molten salt loop, a vaporizer loop and a low-temperature molten salt loop, and controlling the water inlet rate of the vaporizer loop. The application significantly prolongs an emergency disposal window and improves system operation safety and stability.

Description

Technical Field

[0001] This application relates to the field of steam generation technology, and in particular to a graded early warning system for internal leakage of steam generating devices. Background Technology

[0002] Steam, as a core energy carrier in industrial production, is widely used in many industries such as food processing, textile printing and dyeing, biopharmaceuticals, and chemical metallurgy. Its stable, efficient, and economical supply directly determines the continuity of industrial production, product quality, and overall production costs, and is a key indicator for measuring enterprise production efficiency and market competitiveness. Molten salt energy storage steam generation systems, with their technological advantages of high molten salt thermal density, good thermal stability, and long energy storage period, combined with the "peak shaving and valley filling" energy utilization model, have become the preferred alternative to traditional steam generation methods. They convert surplus electricity during off-peak hours into molten salt thermal energy for storage, and release the thermal energy to generate steam during peak periods.

[0003] However, the tube sheets of molten salt energy storage steam generation systems generally adopt a fully welded structure, making it impossible to monitor the internal status online during operation, thus operating as a "black box." Furthermore, because the pressure on the water / steam side is much higher than that on the molten salt side, the most prominent safety hazard is the hidden internal leakage of water or steam into the molten salt side. High-temperature molten salt will rapidly vaporize and expand upon contact with water, easily leading to serious accidents such as system overpressure, equipment damage, and even steam explosions.

[0004] Traditional internal leakage monitoring methods mainly rely on threshold alarms for macroscopic parameters such as temperature and pressure on the molten salt side. These methods can only trigger alarms when the internal leakage has developed to the middle or late stages, resulting in a serious delay in early warning. Moreover, after the warning is issued, simple methods such as manual handling or direct shutdown are often used. This method cannot suppress the development of the situation in the early stages of leakage by adjusting parameters such as flow rate, temperature, and water supply, and it is difficult to meet the requirements for long-term safe operation of molten salt systems. Summary of the Invention

[0005] (a) Technical problems to be solved In view of the above-mentioned shortcomings and deficiencies of the prior art, this application provides a graded early warning system for internal leakage of steam generators. It solves the problem of the traditional internal leakage monitoring method that mainly relies on macroscopic parameter thresholds such as temperature and pressure on the molten salt side to trigger alarms. This method can only trigger alarms in the middle and late stages of internal leakage, resulting in serious delays in early warning. Moreover, after the early warning, the method of manual handling or direct shutdown is often used, which cannot suppress the development of the situation in the early stage of leakage by adjusting parameters such as flow rate, temperature, and feedwater.

[0006] (II) Technical Solution To achieve the above objectives, the main technical solutions adopted in this application include: In a first aspect, embodiments of this application provide a graded early warning system for internal leakage of a steam generator. The system is applied to a steam generator in the field of molten salt energy storage. The system includes a control device. The steam generator includes a low-temperature molten salt circuit, a high-temperature molten salt circuit, an evaporator circuit, and a mixing tank for mixing high-temperature molten salt and low-temperature molten salt. The low-temperature molten salt circuit, the high-temperature molten salt circuit, and the evaporator circuit are all connected to the control device. The control device is used to acquire first moisture concentration data in real time, and based on the first moisture concentration data at each sampling time and a pre-set early leakage warning strategy, to determine when an early leakage exists, acquire first temperature data and second temperature data in real time; wherein, the first moisture concentration data is the moisture concentration of the mixed molten salt at the evaporator loop molten salt outlet after heat exchange; the first temperature data is the temperature of the mixed molten salt at the evaporator loop molten salt outlet after heat exchange; and the second temperature data is the temperature of the mixed molten salt at the evaporator loop molten salt inlet before heat exchange. Based on the first temperature data, second temperature data, and first moisture concentration data at each sampling moment after the early leakage, as well as the pre-set leakage development early warning strategy, when it is determined that leakage is developing, a first control command is sent to the high-temperature molten salt circuit, the evaporator circuit, and the low-temperature molten salt circuit. The first control command is used to control the high-temperature molten salt circuit to reduce the molten salt delivery flow rate, while controlling the ratio of the molten salt delivery flow rate of the low-temperature molten salt circuit and the high-temperature molten salt circuit, and controlling the water inlet rate of the evaporator circuit.

[0007] Optionally, the system further includes an evaporator bypass circuit; the evaporator bypass circuit is connected to the control device; The control device is also used to: acquire first pressure data in real time; wherein, the first pressure data is the pressure of the mixed molten salt at the outlet of the evaporator loop after heat exchange; Based on the first pressure data, first temperature data, second temperature data and first moisture concentration data at each sampling moment after the leakage develops, as well as the pre-set serious internal leakage early warning strategy, it is determined whether there is a serious internal leakage, and when it is determined that there is a serious internal leakage, a second control command is sent to the evaporator bypass circuit, evaporator circuit, high temperature molten salt circuit and low temperature molten salt circuit. The second control command is used to stop the high-temperature molten salt circuit from supplying high-temperature molten salt. In addition, controlling the cryogenic molten salt circuit to increase the cryogenic molten salt delivery rate. Additionally, the evaporator bypass circuit is activated so that the mixed molten salt does not pass through the evaporator circuit but flows directly back to the low-temperature molten salt circuit via the evaporator bypass circuit.

[0008] Optionally, the control device acquires first moisture concentration data in real time, and based on the first moisture concentration data at each sampling time and a pre-set early leakage warning strategy, when it determines that an early leakage exists, acquires first temperature data and second temperature data in real time, including: First moisture concentration data is acquired in real time based on a pre-set first sampling frequency. When the first moisture concentration data at any sampling moment exceeds a pre-set first moisture concentration threshold, the first moisture concentration data at all sampling moments within a first preset time period in the future are recorded to obtain the corresponding first moisture concentration sequence. Based on the first moisture concentration threshold and the first moisture concentration data at each sampling moment in the first moisture concentration sequence, the first moisture concentration exceeding the limit ratio corresponding to the first moisture concentration sequence is determined. The first moisture concentration exceeding the limit ratio is the proportion of the number of first moisture concentration data exceeding the first moisture concentration threshold in the first moisture concentration sequence to the total number of first moisture concentration data in the first moisture concentration sequence. When it is determined that the proportion of the first moisture concentration exceeding the limit is greater than the preset proportion threshold, the rate of change of the first moisture concentration corresponding to the first moisture concentration sequence is determined based on all the first moisture concentration data in the first moisture concentration sequence. When the rate of change of the first moisture concentration corresponding to the first moisture concentration sequence is greater than 0, the first sampling frequency is increased to the preset second sampling frequency. At the same time, the first temperature data and the second temperature data are acquired in real time based on the second sampling frequency.

[0009] Optionally, the control device, based on the first temperature data, second temperature data, and first moisture concentration data at each sampling time after the early leakage, and a pre-set leakage development early warning strategy, when it determines that leakage is developing, sends a first control command to the high-temperature molten salt circuit, the evaporator circuit, and the low-temperature molten salt circuit, including: Based on the first moisture concentration data at each sampling time after the early leakage, the second moisture concentration sequence corresponding to each sampling time after the early leakage is obtained; and based on the second moisture concentration sequence corresponding to each sampling time after the early leakage, the rate of change of the second moisture concentration corresponding to each sampling time after the early leakage is obtained; the second moisture concentration sequence corresponding to any sampling time after the early leakage includes the first moisture concentration data corresponding to multiple consecutive sampling times, including that sampling time. Based on the first temperature data at each sampling time after the early leakage, the first temperature sequence corresponding to each sampling time after the early leakage is obtained; and based on the first temperature sequence corresponding to each sampling time after the early leakage, the first temperature change rate corresponding to each sampling time after the early leakage is obtained; the first temperature sequence corresponding to any sampling time after the early leakage includes the first temperature data corresponding to multiple consecutive sampling times, including that sampling time. Based on the first and second temperature data at each sampling time after the early leakage, the evaporator inlet and outlet temperature difference at each sampling time after the early leakage is obtained. Based on the first moisture concentration data, the second moisture concentration change rate, the first temperature change rate, and the evaporator inlet and outlet temperature difference at each sampling moment after the early leakage, as well as the pre-set leakage development early warning strategy, when it is determined that leakage is developing, the first control command is sent to the high-temperature molten salt circuit, the evaporator circuit, and the low-temperature molten salt circuit.

[0010] Optionally, the leak development early warning strategy includes: When the rate of change of the second moisture concentration at any sampling time after an early leak exceeds the preset threshold for the rate of change of the first moisture concentration, it is determined that a leak has developed. Alternatively, if the first temperature change rate at any sampling time after an early leak is within a preset first temperature change rate range, and the first moisture concentration data at that sampling time is greater than a preset second moisture concentration threshold, then a leak is determined to have developed; wherein the second moisture concentration threshold is greater than the first moisture concentration threshold. Alternatively, if the temperature difference between the evaporator inlet and outlet at any sampling time after an early leak is greater than a pre-set first temperature threshold, it is determined that a leak has developed.

[0011] Optionally, the control device determines whether a serious internal leak exists based on the first pressure data, first temperature data, second temperature data, and first moisture concentration data at each sampling time after the leak develops, as well as a pre-set serious internal leak early warning strategy, including: Based on the first temperature data at each sampling time after the leakage develops, a second temperature sequence corresponding to each sampling time after the leakage develops is obtained; and based on the second temperature sequence corresponding to each sampling time after the leakage develops, the second temperature change rate corresponding to each sampling time after the leakage develops is obtained; the second temperature sequence corresponding to any sampling time after the leakage develops includes the first temperature data corresponding to multiple consecutive sampling times, including that sampling time. Based on the first pressure data at each sampling time after the leakage develops, the first pressure sequence corresponding to each sampling time after the leakage develops is obtained; and based on the first pressure sequence corresponding to each sampling time after the leakage develops, the first pressure change rate corresponding to each sampling time after the leakage develops is obtained; the first pressure sequence corresponding to any sampling time after the leakage develops includes the first pressure data corresponding to multiple consecutive sampling times, including that sampling time. Based on the first pressure change rate, second temperature change rate, and first moisture concentration data at each sampling moment after the leakage develops, as well as the pre-set serious internal leakage early warning strategy, it is determined whether a serious internal leakage exists.

[0012] Optionally, the critical internal leakage early warning strategy includes: When the second temperature change rate at any sampling moment after the leakage has developed is less than the preset first temperature change rate threshold, it is determined that there is a serious internal leak. Alternatively, if the rate of change of the first pressure at any sampling moment after the leakage has developed exceeds a preset rate of change of pressure, a serious internal leak is determined to exist. Alternatively, if the first moisture concentration data at any sampling time after the leak has developed is greater than the pre-set third moisture concentration threshold, a serious internal leak is determined to exist.

[0013] Optionally, the first inlet of the salt mixing tank is connected to the high-temperature molten salt circuit, and the outlet and second inlet of the salt mixing tank are both connected to the low-temperature molten salt circuit. The evaporator circuit and the evaporator bypass circuit are arranged on the connecting pipe between the outlet of the salt mixing tank and the low-temperature molten salt circuit, and the evaporator circuit and the evaporator bypass circuit are arranged in parallel. A first temperature sensor, a first pressure transmitter and a first moisture analyzer are arranged on the connecting pipe between the evaporator circuit and the low-temperature molten salt circuit, and a second temperature sensor is arranged on the connecting pipe between the outlet of the salt mixing tank and the evaporator circuit. The first moisture analyzer is used to acquire first moisture concentration data, the first temperature sensor is used to acquire first temperature data, the second temperature sensor is used to acquire second temperature data, and the first pressure transmitter is used to acquire first pressure data in real time. The first pressure transmitter, the first moisture analyzer, the first temperature sensor, and the second temperature sensor are all connected to the control device.

[0014] Optionally, the cryogenic molten salt circuit includes a cryogenic molten salt tank, a cryogenic molten salt pump, and a cryogenic molten salt regulating valve; the high-temperature molten salt circuit includes a high-temperature molten salt tank and a high-temperature molten salt pump; and the evaporator circuit includes an evaporator and a feedwater regulating valve. The inlet of the low-temperature molten salt tank and the outlet of the mixing salt tank are connected through a first pipeline. The evaporator, the first moisture analyzer, the first temperature sensor and the second temperature sensor are all installed on the first pipeline. The first moisture analyzer and the first temperature sensor are installed on the first pipeline between the evaporator and the low-temperature molten salt tank, and the second temperature sensor is installed on the first pipeline between the evaporator and the outlet of the mixing salt tank. The outlet of the cryogenic molten salt tank and the second inlet of the mixing tank are connected by a second pipeline. The cryogenic molten salt pump is installed on the second pipeline and is used to transport cryogenic molten salt from the cryogenic molten salt tank to the mixing tank. The cryogenic molten salt regulating valve is installed on the second pipeline and is located between the cryogenic molten salt pump and the mixing tank. The outlet of the high-temperature molten salt tank is connected to the first inlet of the mixing salt tank through a third pipeline. The high-temperature molten salt pump is installed on the third pipeline and is used to transport high-temperature molten salt from the high-temperature molten salt tank to the mixing salt tank. The evaporator is supplied with water from the outside through a pre-deployed water supply pipe, and the water supply regulating valve is installed on the water supply pipe; The water supply regulating valve, the cryogenic molten salt pump, the cryogenic molten salt regulating valve, and the high-temperature molten salt pump are all connected to the control device; When the control device determines that a leak is developing, it sends a first control command to the high-temperature molten salt circuit, the evaporator, and the low-temperature molten salt circuit, including: When a leak is confirmed to be developing, a first control command is sent to the water supply regulating valve, the cryogenic molten salt pump, the cryogenic molten salt regulating valve, and the high-temperature molten salt pump; The first control command is used to: control the high-temperature molten salt pump to reduce its power to a preset level to reduce the molten salt delivery flow rate; control the low-temperature molten salt regulating valve to a first preset opening level to control the ratio of the molten salt delivery flow rates of the low-temperature molten salt circuit and the high-temperature molten salt circuit; and control the feedwater regulating valve to a second preset opening level to reduce the feedwater flow rate entering the evaporator.

[0015] Optionally, the evaporator circuit further includes an evaporator brine trap, an evaporator molten salt outlet valve, and an evaporator molten salt inlet valve; the high-temperature molten salt circuit further includes a high-temperature molten salt regulating valve; and the evaporator bypass circuit is an evaporator bypass valve. Specifically, the first position between the evaporator bypass valve and the salt mixing tank is connected to the molten salt inlet of the evaporator through a fourth pipeline, and the second position between the evaporator bypass valve and the low-temperature molten salt tank is connected to the molten salt outlet of the evaporator through a fifth pipeline; the molten salt inlet valve is located on the fourth pipeline, and the molten salt outlet valve is located on the fifth pipeline; the evaporator's salt outlet is connected to the low-temperature molten salt tank's salt outlet through a sixth pipeline, and the evaporator's salt outlet valve is located on the sixth pipeline; The high-temperature molten salt valve is installed on the third pipeline and is located between the high-temperature molten salt pump and the mixing tank; The high-temperature molten salt valve, evaporator desalination valve, evaporator molten salt outlet valve, and evaporator molten salt inlet valve are all connected to the control device. When a serious internal leak is detected, the control device sends a second control command to the evaporator bypass valve, the evaporator circuit, the high-temperature molten salt circuit, and the low-temperature molten salt circuit, including: When a serious internal leak is detected, a fourth control command is sent to the evaporator bypass valve, the evaporator molten salt outlet valve, and the evaporator molten salt inlet valve to fully open the evaporator bypass valve while closing the evaporator molten salt outlet valve and the evaporator molten salt inlet valve. In addition, a fifth control command is sent to the high-temperature molten salt pump to stop the high-temperature molten salt pump and at the same time cause the residual molten salt in the high-temperature molten salt pump to flow back to the high-temperature molten salt tank; In addition, a sixth control command is sent to the low-temperature molten salt regulating valve and the high-temperature molten salt regulating valve to fully open the low-temperature molten salt regulating valve while closing the high-temperature molten salt regulating valve; In addition, a seventh control command is sent to the water supply regulating valve to reduce the water supply regulating valve to the third preset opening degree; And, after sending the sixth control command, at a second preset time, an eighth control command is sent to the evaporator desalination valve to fully open the evaporator desalination valve.

[0016] (III) Beneficial Effects This application discloses a graded early warning system for internal leaks in steam generators. By real-time monitoring of the moisture concentration and temperature data at the molten salt outlet of the evaporator circuit and the temperature data at the outlet of the mixing tank, combined with a control device, it achieves early and accurate identification and graded automatic intervention of internal leaks in the evaporator. It can capture abnormal moisture concentration signals in real time during the micro-leakage stage, effectively eliminate background interference, and reduce the false alarm rate. At the same time, when the leak develops, it automatically adjusts the flow ratio of the high and low temperature molten salt circuit, reduces the molten salt delivery rate and the evaporator water inlet rate, and suppresses the internal leak situation in advance, significantly extending the emergency response window, improving the system's operational safety and stability, and effectively reducing safety accidents such as overpressure and explosions caused by internal leaks. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the steam generator structure provided in the embodiments of this application; Figure 2 A schematic diagram of the early warning process for a graded early warning system for internal leakage of a steam generator, provided in an embodiment of this application; Figure 3 A flowchart illustrating the early leakage warning process provided in this application embodiment; Figure 4 A flowchart illustrating the early warning process for leakage development provided in this application embodiment; Figure 5 A flowchart illustrating the critical internal leakage early warning provided in this application embodiment.

[0018] [Explanation of Labels in the Attached Image] 1: Evaporator; 11: Evaporator molten salt outlet valve; 12: Evaporator molten salt inlet valve; 13: Salt release valve; 14: Evaporator bypass valve; 15: Feedwater regulating valve; 16: First temperature sensor; 17: First pressure transmitter; 18: First moisture analyzer; 2: Low-temperature molten salt tank; 21: Low-temperature molten salt pump; 22: Second moisture analyzer; 23: Low-temperature molten salt regulating valve; 3: High-temperature molten salt tank; 31: High-temperature molten salt pump; 32: Third moisture analyzer; 33: High-temperature molten salt regulating valve; 4: Mixing salt tank; 41: Flow meter; 42: Second pressure transmitter; 43: Second temperature sensor; 44: Fourth moisture analyzer; 51: Overpressure nitrogen release valve; 52: Fifth moisture analyzer. Detailed Implementation

[0019] To better explain and facilitate understanding of this application, the following detailed description of the application is provided in conjunction with the accompanying drawings and specific embodiments.

[0020] Steam is the core energy carrier in industrial production. Molten salt energy storage steam generation systems, with their advantages of high heat storage density, good thermal stability, and strong peak shaving and valley filling capabilities, have become an important alternative to traditional steam generation methods, effectively ensuring a continuous and stable supply of industrial steam. However, the evaporator tube sheet of this system often adopts a fully welded structure, making it impossible to monitor the internal status online during operation. Furthermore, the water / steam side pressure is significantly higher than the molten salt side, making hidden internal leaks prone to causing rapid vaporization of the high-temperature molten salt, leading to system overpressure, equipment damage, or even explosions, posing significant safety risks. Traditional internal leak monitoring relies solely on threshold alarms for macroscopic parameters such as temperature and pressure, which suffers from severe lag, triggering alarms only in the later stages of a leak. Simultaneously, the handling methods are simplistic and crude, often involving manual intervention or direct shutdown, failing to suppress leak development in its early stages and making it difficult to meet the long-term safe operation requirements of the system.

[0021] Therefore, this application provides a graded early warning system for internal leaks in steam generators. By real-time monitoring of the moisture concentration and temperature data at the molten salt outlet of the evaporator circuit and the temperature data at the outlet of the mixing tank, combined with a control device, it achieves early and accurate identification and graded automatic intervention for internal leaks in the evaporator. It can capture abnormal moisture concentration signals in real time during the micro-leakage stage, effectively eliminating background interference and reducing the false alarm rate. Simultaneously, as the leak develops, it automatically adjusts the flow ratio of the high and low temperature molten salt circuits, reduces the molten salt delivery rate and the evaporator inlet water rate, and suppresses internal leaks in advance, significantly extending the emergency response window, improving system operational safety and stability, and effectively reducing safety accidents such as overpressure and explosions caused by internal leaks. To better understand the above technical solutions, exemplary embodiments of this application will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application can be understood more clearly and thoroughly, and that the scope of this application can be fully conveyed to those skilled in the art.

[0022] This application provides a graded early warning system for internal leakage in a steam generator, including a control device and a steam generator, wherein the structure of the steam generator is as follows: Figure 1 As shown, it includes a low-temperature molten salt circuit, a high-temperature molten salt circuit, an evaporator circuit, and a salt mixing tank 4; The control device processing flow is as follows: Figure 2 As shown, it is used for: S1 is used to acquire first moisture concentration data in real time, and based on the first moisture concentration data at each sampling time and the pre-set early leakage warning strategy, to determine when an early leakage exists, acquire first temperature data and second temperature data in real time; wherein, the first moisture concentration data is the moisture concentration of the mixed molten salt at the evaporator loop molten salt outlet after heat exchange; the first temperature data is the temperature of the mixed molten salt at the evaporator loop molten salt outlet after heat exchange; and the second temperature data is the temperature of the mixed molten salt at the evaporator loop molten salt inlet before heat exchange. S2. Based on the first temperature data, second temperature data, and first moisture concentration data at each sampling moment after the early leakage, and the pre-set leakage development early warning strategy, when it is determined that leakage development exists, a first control command is sent to the high-temperature molten salt circuit, the evaporator circuit, and the low-temperature molten salt circuit. The first control command is used to control the high-temperature molten salt circuit to reduce the molten salt delivery flow rate, while controlling the ratio of the molten salt delivery flow rate of the low-temperature molten salt circuit and the high-temperature molten salt circuit, and controlling the water inlet rate of the evaporator circuit.

[0023] This embodiment provides a graded early warning system for internal leaks in steam generators. By real-time monitoring of the moisture concentration and temperature data at the molten salt outlet of the evaporator circuit and the temperature data at the outlet of the mixing tank, combined with a control device, it achieves early and accurate identification and graded automatic intervention for internal leaks in the evaporator. It can capture abnormal moisture concentration signals in real time during the micro-leakage stage, effectively eliminate background interference, and reduce the false alarm rate. At the same time, when the leak develops, it automatically adjusts the flow ratio of the high and low temperature molten salt circuit, reduces the molten salt delivery rate and the evaporator water inlet rate, and suppresses the internal leak situation in advance, significantly extending the emergency response window, improving the system's operational safety and stability, and effectively reducing safety accidents such as overpressure and explosions caused by internal leaks.

[0024] Furthermore, the internal leakage classification early warning system for steam generators provided in this application is applied to the energy utilization field where molten salt energy storage technology and industrial steam generation systems intersect. Its core application scenarios are industries such as food processing, textile printing and dyeing, biopharmaceuticals, and chemical metallurgy, which have high requirements for stable supply of industrial steam, precise temperature control, energy saving and carbon reduction. It is also suitable for scenarios that require "peak shaving and valley filling" energy utilization modes, such as steam supply for new energy power plants and centralized steam supply for industrial parks. It is a special application of molten salt energy storage technology in the field of industrial thermal energy supply.

[0025] Conventional technologies (including traditional steam generation technology, general molten salt energy storage technology, and ordinary industrial heat exchange temperature control technology) cannot be directly applied to this field. The core reason is that this field has the combined requirements of molten salt energy storage medium characteristics, steam generation process requirements, and industrial continuous operation safety requirements. Conventional technologies cannot meet the multiple technical pain points and scenario requirements of this field. Traditional steam generation, general molten salt energy storage, and ordinary heat exchange temperature control technologies only use macroscopic parameter thresholds such as temperature and pressure for judgment, lacking the ability to monitor moisture online and eliminate background interference. They are unable to identify early micro-internal leaks in the fully welded structure of evaporator 1, resulting in problems such as delayed warnings and high false alarm rates. At the same time, conventional systems lack high and low temperature molten salt ratio adjustment and graded linkage control logic, making it impossible to achieve early intervention and situation suppression. Furthermore, they cannot cope with special high-risk scenarios where water / steam pressure is higher than the molten salt side and high-temperature molten salt vaporizes and explodes upon contact with water.

[0026] Furthermore, the first inlet of the salt mixing tank 4 is connected to the high-temperature molten salt circuit, and the outlet and second inlet of the salt mixing tank 4 are both connected to the low-temperature molten salt circuit. The evaporator circuit and the evaporator bypass circuit are set on the connecting pipe between the outlet of the salt mixing tank 4 and the low-temperature molten salt circuit, and the evaporator circuit and the evaporator bypass circuit are set in parallel. A first temperature sensor 16, a first pressure transmitter 17 and a first moisture analyzer 18 are set on the connecting pipe between the evaporator circuit and the low-temperature molten salt circuit. A second temperature sensor 43 is set on the connecting pipe between the outlet of the salt mixing tank and the evaporator circuit. The first moisture analyzer 18 is used to acquire first moisture concentration data, the first temperature sensor 16 is used to acquire first temperature data, the second temperature sensor 43 is used to acquire second temperature data, and the first pressure transmitter 17 is used to acquire first pressure data in real time. The first pressure transmitter 17, the first moisture analyzer 18, the first temperature sensor 16, and the second temperature sensor 43 are all connected to the control device.

[0027] Optionally, in one specific embodiment, the control device acquires first moisture concentration data in real time, and based on the first moisture concentration data at each sampling time and a pre-set early leakage warning strategy, when it determines that an early leakage exists, acquires first temperature data and second temperature data in real time, such as... Figure 3 The above includes: S11. Based on a pre-set first sampling frequency, first moisture concentration data is acquired in real time. When the first moisture concentration data at any sampling moment exceeds a pre-set first moisture concentration threshold, the first moisture concentration data of all sampling moments in the future first preset time period of that sampling moment is recorded to obtain the corresponding first moisture concentration sequence. S12. Based on the first moisture concentration threshold and the first moisture concentration data at each sampling time in the first moisture concentration sequence, determine the first moisture concentration exceeding the limit ratio corresponding to the first moisture concentration sequence. The first moisture concentration exceeding the limit ratio is the proportion of the number of first moisture concentration data exceeding the first moisture concentration threshold in the first moisture concentration sequence to all first moisture concentration data in the first moisture concentration sequence. S13. When it is determined that the proportion of the first moisture concentration exceeding the limit is greater than the preset proportion threshold, the rate of change of the first moisture concentration corresponding to the first moisture concentration sequence is determined based on all the first moisture concentration data in the first moisture concentration sequence. S14. When the rate of change of the first moisture concentration corresponding to the first moisture concentration sequence is greater than 0, the first sampling frequency is increased to the preset second sampling frequency. At the same time, the first temperature data and the second temperature data are acquired in real time based on the second sampling frequency.

[0028] Specifically, firstly, the control device continuously acquires the first moisture concentration data at the initial sampling frequency. The first moisture concentration data is collected in real time by the first moisture analyzer 18 (laser online moisture analyzer) installed at the molten salt outlet of the evaporator loop, representing the moisture content in the molten salt at the outlet of evaporator 1.

[0029] When the first moisture concentration data at any sampling time exceeds the first moisture concentration threshold, it is determined that a single exceedance has occurred. The system does not immediately alarm, but instead enters the trend verification stage. The first moisture concentration threshold is a preset early warning threshold value of the system, which can be a fixed value.

[0030] Secondly, after entering the trend verification stage, starting from the time of exceeding the limit, the system automatically records the first moisture concentration data of all sampling points within the first preset time period, forming a continuous first moisture concentration sequence. The first preset time period is used as a time window for determining the trend, such as 10 minutes, to cover multiple consecutive sets of sampling points.

[0031] Then, the control device counts the number of data points exceeding the first moisture concentration threshold and the total number of data points in the first moisture concentration sequence, and calculates the first moisture concentration exceeding the limit percentage (first moisture concentration exceeding the limit percentage = number of exceeding points / total number of points); first moisture concentration exceeding the limit percentage: the number of sampling points with moisture concentration exceeding the threshold / the total number of sampling points within a first preset time period, used to eliminate instantaneous interference.

[0032] When the percentage exceeding the limit is greater than the preset threshold (e.g., 80%), it indicates that the moisture concentration is consistently high rather than fluctuating momentarily, and the process enters the trend determination stage.

[0033] Furthermore, after entering the trend determination, the rate of change of the first moisture concentration is calculated based on the first moisture concentration sequence using the difference or least squares method.

[0034] When the rate of change is greater than 0, it indicates that the moisture concentration is continuously rising, which is consistent with the early characteristics of internal leakage; when the rate of change is less than or equal to 0, it is determined to be a fluctuation or interference, and the verification is terminated and regular monitoring is resumed.

[0035] Finally, when both the over-limit percentage and the rate of change are met, the control device determines that an early leak exists and executes: A third control command is sent to the first moisture analyzer 18 to increase the sampling frequency to a preset high-frequency value, thereby achieving more intensive and sensitive data acquisition. The first temperature sensor 16 and the second temperature sensor 43 are activated simultaneously, and the data is acquired in real time. First temperature data: molten salt outlet temperature in the evaporator loop; Second temperature data: outlet temperature of mixing tank 4 provides cross-validation parameters such as temperature trend and inlet / outlet temperature difference for subsequent leakage development classification and early warning.

[0036] Furthermore, the sampling frequencies of the first temperature sensor 16 and the second temperature sensor 43 are always consistent with those of the first moisture analyzer 18.

[0037] Furthermore, the first temperature sensor 16 and the second temperature sensor 43 can also start collecting data synchronously with the first moisture analyzer 18, and simultaneously increase the sampling frequency.

[0038] This embodiment employs a progressive judgment logic that includes initial monitoring, single-time over-limit triggering, time window sequence statistics, over-limit percentage filtering, change rate trend verification, and adaptive increase in sampling frequency. This logic enables accurate identification of abnormal moisture concentration in the early micro-leakage stage, effectively filtering instantaneous fluctuations and system background noise, significantly reducing the false alarm rate. Simultaneously, after confirming an early leak, it automatically increases the sampling frequency of moisture and temperature signals, achieving denser and more sensitive data acquisition. This provides reliable multi-parameter cross-validation for subsequent graded early warning, balancing the stability, sensitivity, and real-time performance of the system monitoring, and significantly improving the accuracy and response efficiency of early identification of internal leaks.

[0039] Optionally, in one specific embodiment, the control device, based on the first temperature data, second temperature data, and first moisture concentration data at each sampling time after the early leakage, and a pre-set leakage development early warning strategy, determines that leakage development exists, and then sends a first control command to the high-temperature molten salt circuit, the evaporator circuit, and the low-temperature molten salt circuit, such as... Figure 4 As shown, it includes: S21. Based on the first moisture concentration data at each sampling time after the early leakage, obtain the second moisture concentration sequence corresponding to each sampling time after the early leakage; and based on the second moisture concentration sequence corresponding to each sampling time after the early leakage, obtain the rate of change of the second moisture concentration corresponding to each sampling time after the early leakage; the second moisture concentration sequence corresponding to any sampling time after the early leakage includes the first moisture concentration data corresponding to multiple consecutive sampling times, including that sampling time. S22. Based on the first temperature data at each sampling time after the early leakage, obtain the first temperature sequence corresponding to each sampling time after the early leakage; and based on the first temperature sequence corresponding to each sampling time after the early leakage, obtain the first temperature change rate corresponding to each sampling time after the early leakage; the first temperature sequence corresponding to any sampling time after the early leakage includes the first temperature data corresponding to multiple consecutive sampling times, including that sampling time. S23. Based on the first and second temperature data at each sampling time after the early leakage, obtain the inlet and outlet temperature difference of evaporator 1 at each sampling time after the early leakage. S24. Based on the first moisture concentration data, the second moisture concentration change rate, the first temperature change rate, and the temperature difference between the inlet and outlet of evaporator 1 at each sampling time after the early leakage, and the pre-set leakage development early warning strategy, when it is determined that there is leakage development, the first control command is sent to the high-temperature molten salt circuit, the evaporator circuit, and the low-temperature molten salt circuit.

[0040] Furthermore, leak development early warning strategies include: When the rate of change of the second moisture concentration at any sampling time after an early leak exceeds the preset threshold for the rate of change of the first moisture concentration, it is determined that a leak has developed. Alternatively, if the first temperature change rate at any sampling time after an early leak is within a preset first temperature change rate range, and the first moisture concentration data at that sampling time is greater than a preset second moisture concentration threshold, then a leak is determined to have developed; wherein the second moisture concentration threshold is greater than the first moisture concentration threshold. Alternatively, if the temperature difference between the inlet and outlet of evaporator 1 at any sampling time after an early leak is greater than a pre-set first temperature threshold, it is determined that a leak has developed.

[0041] Specifically, after confirming an early leak, the control device maintains high-frequency sampling and continuously collects: first moisture concentration data, first temperature data, and second temperature data, providing a continuous and stable data source for subsequent trend calculations.

[0042] Subsequently, the second moisture concentration sequence and the rate of change of the second moisture concentration were calculated time-by-time, i.e.: Using the current sampling time as a marker, extract N consecutive points (e.g., 3-5 points) to form a second moisture concentration sequence; typically, the second moisture concentration sequence uses the current sampling time as the endpoint / midpoint. Linear fitting of the sequence yields the second rate of change in water concentration, which represents the intensity of the upward trend in water concentration at the current moment. The higher the rate, the more pronounced the internal leakage.

[0043] Then, the first temperature sequence and the first temperature change rate are calculated at time 1, i.e.: Similar to the second moisture concentration method, the current sampling time is used as the endpoint / midpoint to extract N consecutive first temperature data to form a first temperature sequence; the temperature sequence is fitted to obtain the first temperature change rate; where, when internal leakage occurs, water vaporizes and absorbs heat, and the outlet temperature will drop, so the temperature change rate is negative, and the larger the absolute value, the faster the cooling.

[0044] Furthermore, a three-condition judgment is made based on the leak development early warning strategy. A leak is considered to be developing when any of the following conditions are met: Condition 1 is an accelerated increase in moisture concentration, i.e., the second rate of change in moisture concentration > the first rate of change in moisture concentration threshold, indicating a significant increase in leakage and a rapid rise in moisture content; Condition 2 is a slow decrease in temperature and a moderate exceedance of moisture concentration, i.e., the first rate of change in temperature falls within a preset range (e.g., ...). 3℃ / min~ 1℃ / min), that is, the current first moisture concentration data is greater than the second moisture concentration threshold (greater than the early warning threshold), indicating that the temperature is steadily decreasing and the moisture continues to exceed the standard, and the double confirmation content is developing; condition 3 is that the temperature difference between the inlet and outlet of evaporator 1 increases abnormally, that is, the temperature difference between the inlet and outlet of evaporator 1 is greater than the preset first temperature threshold, which indicates that the heat exchange efficiency has deteriorated significantly.

[0045] Finally, when any of the above conditions are met, the control device immediately sends a first control command to each loop to execute the linkage control: The high-temperature molten salt circuit reduces the molten salt transport flow rate and decreases the heat entering evaporator 1; The system combines a low-temperature molten salt circuit with a high-temperature molten salt circuit, adjusting the flow ratio to increase the proportion of low-temperature molten salt and reduce the inlet molten salt temperature of evaporator 1.

[0046] Evaporator circuit (water side): Reduce water inlet rate, decrease leakage source intensity, and suppress violent reaction between high-temperature molten salt and water.

[0047] Based on the determination of early leakage, this embodiment proceeds to leakage development judgment and automatic intervention. Through multi-parameter, sliding window, and multi-condition redundancy judgment, it accurately identifies whether the internal leakage has entered the development stage and outputs control commands to achieve graded early warning and process linkage.

[0048] Optionally, in a specific embodiment, the evaporator bypass circuit includes an evaporator bypass valve 14, which is disposed on the connecting pipeline between the outlet of the salt mixing tank 4 and the low-temperature molten salt circuit, and the evaporator bypass valve 14 is disposed in parallel with the evaporator circuit. A first pressure transmitter 17 is installed on the connecting pipeline between the evaporator circuit and the low-temperature molten salt circuit, and the first pressure transmitter 17 is connected to the control device. The control device is also used for: S3. Real-time acquisition of first pressure data; and based on the first pressure data, first temperature data, second temperature data, and first moisture concentration data at each sampling moment after the leakage develops, as well as the pre-set serious internal leakage early warning strategy, to determine whether a serious internal leakage exists. When a serious internal leakage is determined to exist, a second control command is sent to the evaporator bypass valve 14, the evaporator circuit, the high-temperature molten salt circuit, and the low-temperature molten salt circuit; wherein, the first pressure data is the pressure of the mixed molten salt after heat exchange at the molten salt outlet of the evaporator circuit. The second control command is used to stop the high-temperature molten salt circuit from supplying high-temperature molten salt. In addition, controlling the cryogenic molten salt circuit to increase the cryogenic molten salt delivery rate. Additionally, the evaporator bypass circuit is activated so that the mixed molten salt does not pass through the evaporator circuit but flows directly back to the low-temperature molten salt circuit via the evaporator bypass circuit.

[0049] Furthermore, the control device, based on the first pressure data, first temperature data, second temperature data, and first moisture concentration data at each sampling moment after the leak develops, as well as a pre-set severe internal leak early warning strategy, determines whether a severe internal leak exists, such as... Figure 5 As shown, it includes: S31. Based on the first temperature data at each sampling time after the leakage develops, obtain the second temperature sequence corresponding to each sampling time after the leakage develops; and based on the second temperature sequence corresponding to each sampling time after the leakage develops, obtain the second temperature change rate corresponding to each sampling time after the leakage develops; the second temperature sequence corresponding to any sampling time after the leakage develops includes the first temperature data corresponding to multiple consecutive sampling times, including that sampling time. S32. Based on the first pressure data at each sampling time after the leakage develops, obtain the first pressure sequence corresponding to each sampling time after the leakage develops; and based on the first pressure sequence corresponding to each sampling time after the leakage develops, obtain the first pressure change rate corresponding to each sampling time after the leakage develops; the first pressure sequence corresponding to any sampling time after the leakage develops includes the first pressure data corresponding to multiple consecutive sampling times, including that sampling time. S33. Based on the first pressure change rate, second temperature change rate and first moisture concentration data at each sampling moment after the leakage develops, and the pre-set serious internal leakage early warning strategy, determine whether a serious internal leakage exists.

[0050] Among them, the early warning strategy for severe internal leaks includes: When the second temperature change rate at any sampling moment after the leakage has developed is less than the preset first temperature change rate threshold, it is determined that there is a serious internal leak. Alternatively, if the rate of change of the first pressure at any sampling moment after the leakage has developed exceeds a preset rate of change of pressure, a serious internal leak is determined to exist. Alternatively, if the first moisture concentration data at any sampling time after the leak has developed is greater than the pre-set third moisture concentration threshold, a serious internal leak is determined to exist.

[0051] Specifically, in this embodiment, the evaporator bypass valve 14 is installed on the pipeline from the outlet of the mixing tank 4 to the low-temperature molten salt circuit, and is connected in parallel with the evaporator circuit. It is used to quickly open the bypass in case of severe internal leakage, so that the molten salt can flow back directly without passing through the evaporator 1.

[0052] The evaporator circuit molten salt inlet switch valve and outlet switch valve are located on the inlet and outlet pipelines of evaporator 1, respectively, and are used to quickly close in case of serious internal leakage, so as to isolate evaporator 1 from the system; the first pressure transmitter 17 is installed on the connecting pipeline between the evaporator circuit and the low temperature molten salt circuit, and collects the molten salt side outlet pressure of evaporator 1 in real time, i.e., the first pressure data.

[0053] After entering the critical internal leak monitoring stage, the control device, based on the established leak development, continues to synchronously acquire the following data using a high-frequency sampling mode: first temperature data (evaporator 1 outlet temperature), second temperature data (evaporator 1 inlet temperature), first moisture concentration data, and first pressure data (evaporator 1 outlet pressure). Based on this, it calculates the critical characteristic frequency on a time-by-time basis, namely: The second temperature change rate is calculated by taking the current sampling time as the endpoint / midpoint, taking N consecutive first temperature data to form a second temperature sequence, and calculating the second temperature change rate by least squares method or central difference method, which reflects whether the temperature drops sharply.

[0054] The first pressure change rate is calculated by taking the current sampling time as the end point / midpoint, taking N consecutive first pressure data to form the first pressure sequence, and calculating the first pressure change rate to reflect whether the pressure rises sharply.

[0055] Finally, following the severe internal leakage strategy, a three-condition judgment is performed. A severe internal leakage is immediately identified if any of the following conditions are met: First, if the second temperature change rate is less than the first temperature change rate threshold, it indicates that the outlet temperature of evaporator 1 drops sharply, and the high-temperature molten salt vaporizes and absorbs heat in large quantities upon contact with water, reaching a dangerous level.

[0056] Second, if the first pressure change rate is greater than the pressure change rate threshold, it indicates that the pressure on the molten salt side of evaporator 1 is rising rapidly, water vaporization is intense, and the system is about to overpressure.

[0057] Third, if the first moisture concentration data is greater than the third moisture concentration threshold, it means that the moisture in the molten salt has reached the critical concentration for explosion, and immediate emergency measures must be taken.

[0058] Upon detecting a severe internal leak, the device immediately outputs a second control command and simultaneously executes the following actions: controls the evaporator bypass valve 14 to open rapidly, allowing molten salt to bypass and return, preventing it from entering evaporator 1; controls the evaporator circuit to quickly close the molten salt inlet and outlet valves, achieving complete isolation of evaporator 1; controls the high-temperature molten salt circuit to immediately stop molten salt delivery and supply; controls the low-temperature molten salt circuit to increase the molten salt delivery rate, rapidly cooling the upstream residual salt and suppressing the vaporization reaction; and performs the highest-level safety actions in conjunction with reducing water supply, delaying salt removal, and triggering an alarm.

[0059] This embodiment provides the system with a third-level early warning. Based on the judgment of leakage development, it performs real-time monitoring and multi-condition trigger judgment on three types of critical characteristics: sudden temperature drop, sudden pressure rise, and serious exceedance of moisture concentration. Once confirmed, it immediately executes the highest level of safety interlocks such as emergency cut-off, bypass connection, shutdown, cooling, and salt removal to avoid catastrophic accidents such as explosion and overpressure rupture.

[0060] Optionally, in a specific embodiment, the cryogenic molten salt circuit includes a cryogenic molten salt tank 2, a cryogenic molten salt pump 21, and a cryogenic molten salt regulating valve 23; the high-temperature molten salt circuit includes a high-temperature molten salt tank 3, and a high-temperature molten salt pump 31; the evaporator circuit includes an evaporator 1 and a feedwater regulating valve 15. The inlet of the low-temperature molten salt tank 2 is connected to the outlet of the salt mixing tank 4 through a first pipeline. The evaporator 1, the first moisture analyzer 18, the first temperature sensor 16 and the second temperature sensor 43 are all installed on the first pipeline. The first moisture analyzer 18 and the first temperature sensor 16 are installed on the first pipeline between the evaporator 1 and the low-temperature molten salt tank 2, and the second temperature sensor 43 is installed on the first pipeline between the evaporator 1 and the outlet of the salt mixing tank 4. The outlet of the low-temperature molten salt tank 2 and the second inlet of the mixing tank 4 are connected by a second pipeline. The low-temperature molten salt pump 21 is installed on the second pipeline and is used to transport low-temperature molten salt from the low-temperature molten salt tank 2 to the mixing tank 4. The low-temperature molten salt regulating valve 23 is installed on the second pipeline and is located between the low-temperature molten salt pump 21 and the mixing tank 4. The outlet of the high-temperature molten salt tank 3 is connected to the first inlet of the mixing salt tank 4 through a third pipeline. The high-temperature molten salt pump 31 is installed on the third pipeline and is used to transport high-temperature molten salt from the high-temperature molten salt tank 3 to the mixing salt tank 4. Evaporator 1 is supplied with water from the outside through a pre-deployed water supply pipe, and water supply regulating valve 15 is installed on the water supply pipe; Water supply regulating valve 15, low-temperature molten salt pump 21, low-temperature molten salt regulating valve 23 and high-temperature molten salt pump 31 are all connected to the control device; When the control device determines that a leak is developing, it sends a first control command to the high-temperature molten salt circuit, evaporator 1, and low-temperature molten salt circuit, including: When a leak is confirmed to be developing, a first control command is sent to the water supply regulating valve 15, the cryogenic molten salt pump 21, the cryogenic molten salt regulating valve 23, and the high-temperature molten salt pump 31; The first control command is used to: control the high-temperature molten salt pump 31 to reduce its power to reduce the molten salt delivery flow rate; control the low-temperature molten salt regulating valve 23 to a first preset opening degree to control the ratio of the molten salt delivery flow rates of the low-temperature molten salt circuit and the high-temperature molten salt circuit; and control the water supply regulating valve 15 to a second preset opening degree to reduce the water supply flow rate entering the evaporator 1.

[0061] Furthermore, the evaporator circuit also includes an evaporator 1 brine release valve 13, an evaporator 1 molten salt outlet valve 11, and an evaporator 1 molten salt inlet valve 12; the high-temperature molten salt circuit also includes a high-temperature molten salt regulating valve 33; Specifically, the first position between the evaporator bypass valve 14 and the salt mixing tank 4 is connected to the molten salt inlet of the evaporator 1 through a fourth pipeline, and the second position between the evaporator bypass valve 14 and the low-temperature molten salt tank 2 is connected to the molten salt outlet of the evaporator 1 through a fifth pipeline; the molten salt inlet valve is located on the fourth pipeline, and the molten salt outlet valve is located on the fifth pipeline; the salt evaporation port of the evaporator 1 is connected to the salt evaporation port of the low-temperature molten salt tank 2 through a sixth pipeline, and the salt evaporation valve 13 of the evaporator 1 is located on the sixth pipeline; The high-temperature molten salt valve is installed on the third pipeline and is located between the high-temperature molten salt pump 31 and the salt mixing tank 4; The high-temperature molten salt valve, the evaporator 1 salt release valve 13, the evaporator 1 molten salt outlet valve 11, and the evaporator 1 molten salt inlet valve 12 are all connected to the control device; When a serious internal leak is detected, the control device sends a second control command to the evaporator bypass valve 14, the evaporator circuit, the high-temperature molten salt circuit, and the low-temperature molten salt circuit, including: When a serious internal leak is determined, a fourth control command is sent to the molten salt bypass regulating valve of evaporator 1, the molten salt outlet valve 11 of evaporator 1, and the molten salt inlet valve 12 of evaporator 1, so as to fully open the molten salt bypass regulating valve of evaporator 1 while closing the molten salt outlet valve 11 and the molten salt inlet valve 12 of evaporator 1. In addition, a fifth control command is sent to the high-temperature molten salt pump 31 to stop the high-temperature molten salt pump 31 and at the same time, cause the residual molten salt in the high-temperature molten salt pump 31 to flow back to the high-temperature molten salt tank 3; In addition, a sixth control command is sent to the low-temperature molten salt regulating valve 23 and the high-temperature molten salt regulating valve 33 to fully open the low-temperature molten salt regulating valve 23 while closing the high-temperature molten salt regulating valve 33. And, send a seventh control command to the water supply regulating valve 15 to reduce the water supply regulating valve 15 to the third preset opening degree; And, after sending the sixth control command, at a second preset time, an eighth control command is sent to the evaporator 1 salt-free valve 13 to fully open the evaporator 1 salt-free valve 13.

[0062] Specifically, after the control device determines that a leak has developed, it sends a first control command to the high-temperature molten salt pump 31, the low-temperature molten salt regulating valve 23, and the water supply regulating valve 15, and simultaneously executes the following actions: Control the high-temperature molten salt pump 31 to reduce its power to a preset level, that is, reduce the output frequency / speed, reduce the high-temperature molten salt delivery flow rate, and reduce the heat load entering the evaporator 1 to slow down the leakage vaporization reaction; Control the low-temperature molten salt regulating valve 23 to open to the first preset opening degree, that is, increase the proportion of low-temperature molten salt fed into the mixing tank 4, and reduce the outlet temperature of the mixing tank 4, thereby reducing the inlet molten salt temperature of the evaporator 1, and realizing automatic adjustment of the low-temperature / high-temperature molten salt flow ratio. The water supply regulating valve 15 is closed to the second preset opening degree, that is, the water inlet flow rate and pressure of the evaporator 1 are reduced, and the leakage driving force of water / steam to the molten salt side is reduced, so as to suppress the further expansion of internal leakage.

[0063] Based on the above combination of actions, pre-intervention measures such as reducing flow rate, adjusting temperature, and reducing water supply can be implemented to buy time for manual handling.

[0064] After determining a serious internal leak, the control device sends multiple control commands in the following sequence: first, isolate the heat source; then, cool the system; and finally, safely evacuate the system. The details are as follows: Send a fourth control command to achieve bypass and isolation of evaporator 1, which is used to fully open evaporator bypass valve 14, quickly close evaporator 1 molten salt inlet valve 12, and quickly close evaporator 1 molten salt outlet valve 11. Send the fifth control command to stop the high-temperature heat source. That is, immediately stop the high-temperature molten salt pump 31, start the pump recirculation, and let the remaining high-temperature molten salt flow back to the high-temperature molten salt tank 3.

[0065] A sixth control command is sent to achieve emergency forced cooling, which is used to fully open the low-temperature molten salt regulating valve 23 and close the high-temperature molten salt regulating valve 33.

[0066] Send the seventh control command to achieve emergency water source suppression, which is used to quickly close the water supply regulating valve 15 to the third preset opening degree (nearly fully closed).

[0067] Send the eighth control command to achieve delayed safe salt discharge (executed after the second preset time). This command fully opens the salt discharge valve 13 of the evaporator 1 after waiting for the second preset time (e.g., a few seconds, to ensure that the temperature has dropped), so that the molten salt in the evaporator 1 is safely discharged into the low-temperature molten salt tank 2 under the action of gravity and residual pressure.

[0068] This embodiment effectively suppresses the expansion of internal leaks and extends emergency response time by automatically reducing flow rate, adjusting temperature, and reducing water supply during the leak development stage. In the stage of severe internal leaks, following the logic of first isolating the heat source, then cooling the system, and finally safely draining, the bypass is connected, evacuator 1 is isolated, heat source is cut off, forced cooling, water-side source suppression, and delayed salt drainage are completed in sequence. This cuts off the risk of contact between high-temperature molten salt and water vapor from the source, avoiding vaporization explosion and equipment overpressure accidents. At the same time, it makes full use of the existing pipelines and actuators of the system, greatly improving the operational stability and response time of the molten salt steam generation system.

[0069] Furthermore, multiple pipelines can be set up for salt removal, that is, two or more salt removal valves 13 can be set on different salt removal pipelines.

[0070] Furthermore, the system also includes an overpressure nitrogen relief valve 51; The pressure balance port of the high-temperature molten salt pump 31 and the pressure balance port of the low-temperature molten salt pump 21 are connected through a nitrogen sealing connecting pipe, and the overpressure nitrogen relief valve 51 is installed on the nitrogen sealing connecting pipe. The overpressure nitrogen relief valve 51 is a self-operated micro-pressure relief valve installed on the nitrogen sealing exhaust manifold of the molten salt tank. It automatically opens to exhaust gas when the gas phase pressure in the tank exceeds the set value and automatically closes after the pressure drops to a safe range. In this application, it is mainly used to maintain the pressure stability of the nitrogen sealing system of the molten salt tank and prevent overpressure in the tank caused by temperature fluctuations, changes in molten salt volume, or gas generated by internal leakage. At the same time, it works with an online moisture analyzer to collect characteristic gases, providing reliable gas samples and a safe operating environment for early warning of internal leakage in the evaporator 1, and avoiding safety risks caused by tank overpressure deformation, seal failure, or gas accumulation.

[0071] Furthermore, a flow meter 41 is installed on the pipeline between the outlet of the salt mixing tank 4 and the inlet switch valve of the evaporator 1. The flow meter 41 is located near the outlet of the salt mixing tank 4 and can monitor the instantaneous flow rate and cumulative flow rate of the molten salt entering the evaporator 1 in real time. This provides key process operating parameters for the control device and can help verify whether the molten salt flow rate adjustment is in place when internal leakage occurs and whether heat exchange abnormalities are related to flow fluctuations. This further improves the accuracy and reliability of internal leakage early warning and graded control, while ensuring that the system can achieve accurate monitoring and closed-loop regulation of flow rate during pre-intervention and emergency handling.

[0072] Furthermore, a second moisture analyzer 22 is installed on the low-temperature molten salt tank 2 for real-time monitoring of the second moisture concentration data inside the low-temperature molten salt tank 2; a third moisture analyzer 32 is installed on the high-temperature molten salt tank 3 for real-time monitoring of the third moisture concentration data inside the high-temperature molten salt tank 3; a fourth moisture analyzer 44 is installed on the pipeline between the outlet of the mixed salt tank 4 and the inlet switch valve of the evaporator 1 for real-time monitoring of the fourth moisture concentration data at the outlet of the mixed salt tank 4; and a fifth moisture analyzer 52 is installed on the exhaust port of the overpressure nitrogen release valve 51 for real-time monitoring of the fifth moisture concentration data at the exhaust port of the overpressure nitrogen release valve 51.

[0073] The second moisture analyzer 22, the third moisture analyzer 32, the fourth moisture analyzer 44, and the fifth moisture analyzer 52 described above all function similarly to the first moisture analyzer 18. Furthermore, the second, third, fourth, and fifth moisture concentration data all function similarly to the first moisture concentration data and can synchronously replace the first moisture concentration data in the above scheme, with only the monitoring location being different. The second moisture analyzer 22, the third moisture analyzer 32, the fourth moisture analyzer 44, and the fifth moisture analyzer 52 serve the same function as the first moisture analyzer 18. They are installed at different monitoring points, such as the low-temperature molten salt tank 2, the high-temperature molten salt tank 3, the nitrogen vent, and the inlet of the evaporator 1. The second to fifth moisture concentration data collected have the same function as the first moisture concentration data, with only the monitoring location differing. They can be synchronously and equivalently replaced with the first moisture concentration data in the early leakage warning, leakage development judgment, and severe internal leakage warning strategies of this application. This enables multi-point moisture monitoring, dynamic background calibration, cross-validation comparison, and full-domain anomaly capture, effectively eliminating background noise interference from the system, further improving the sensitivity, accuracy, and anti-interference capability of internal leakage detection, and strengthening the reliability and safety of graded early warning.

[0074] Furthermore, a second pressure transmitter 42 is installed on the pipeline between the outlet of the salt mixing tank 4 and the inlet switch valve of the evaporator 1 to monitor the second pressure data of the outlet of the salt mixing tank 4 in real time. Its function is similar to that of the first pressure transmitter 17. The second pressure data it monitors can also replace the first pressure data in the scheme. Only the monitoring position is different. It can monitor and collect the second pressure data from the outlet of the salt mixing tank 4 to the inlet side of the evaporator 1 in real time. It can form a dual-sided monitoring and cross-comparison of the inlet and outlet pressure of the evaporator 1 with the first pressure transmitter 17. By using the pressure difference and pressure change rate, it can help judge the abnormal pressure fluctuations caused by internal leakage. It can provide a more comprehensive and reliable pressure characteristic basis for the judgment of leakage development and the early warning of serious internal leakage, thereby improving the integrity of system pressure monitoring, the accuracy of early warning and the reliability of safety protection.

[0075] In addition, the first moisture concentration threshold, the second moisture concentration threshold and the third moisture concentration threshold in the embodiments of this application are all determined by the second moisture concentration data during the stable operation of the system (i.e., when no early leakage is detected). They are usually the second moisture concentration data during the stable operation of the system (i.e., when no early leakage is detected), which is the background value of the cryogenic tank.

[0076] Furthermore, after collecting the first, third, fourth, and fifth moisture concentration data, each can be subtracted from the second moisture concentration data collected at the same sampling time. This difference is then compared to the first, second, or third moisture concentration threshold. In this case, the first moisture concentration threshold is 20% of the cryogenic tank background value, the second moisture concentration threshold is 30% to 80% of the cryogenic tank background value (which can be set manually), and the third moisture concentration threshold is 100% of the cryogenic tank background value. The second moisture concentration data can be directly subtracted from the cryogenic tank background value and then directly compared to the first, second, or third moisture concentration threshold.

[0077] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0078] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0079] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0080] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0081] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A graded early warning system for internal leakage in a steam generator, characterized in that, The system is applied to a steam generator in the field of molten salt energy storage. The system includes a control device. The steam generator includes a low-temperature molten salt circuit, a high-temperature molten salt circuit, an evaporator circuit, and a mixing tank for mixing high-temperature molten salt and low-temperature molten salt. The low-temperature molten salt circuit, the high-temperature molten salt circuit, and the evaporator circuit are all connected to the control device. The control device is used to acquire first moisture concentration data in real time, and based on the first moisture concentration data at each sampling time and a pre-set early leakage warning strategy, to determine when an early leakage exists, acquire first temperature data and second temperature data in real time; wherein, the first moisture concentration data is the moisture concentration of the mixed molten salt at the evaporator loop molten salt outlet after heat exchange; the first temperature data is the temperature of the mixed molten salt at the evaporator loop molten salt outlet after heat exchange; and the second temperature data is the temperature of the mixed molten salt at the evaporator loop molten salt inlet before heat exchange. Based on the first temperature data, second temperature data, and first moisture concentration data at each sampling moment after the early leakage, as well as the pre-set leakage development early warning strategy, when it is determined that leakage is developing, a first control command is sent to the high-temperature molten salt circuit, the evaporator circuit, and the low-temperature molten salt circuit. The first control command is used to control the high-temperature molten salt circuit to reduce the molten salt delivery flow rate, while controlling the ratio of the molten salt delivery flow rate of the low-temperature molten salt circuit and the high-temperature molten salt circuit, and controlling the water inlet rate of the evaporator circuit. The system also includes an evaporator bypass circuit; the evaporator bypass circuit is connected to the control device; The control device is also used to: acquire first pressure data in real time; wherein, the first pressure data is the pressure of the mixed molten salt at the outlet of the evaporator loop after heat exchange; Based on the first pressure data, first temperature data, second temperature data and first moisture concentration data at each sampling moment after the leakage develops, as well as the pre-set serious internal leakage early warning strategy, it is determined whether there is a serious internal leakage, and when it is determined that there is a serious internal leakage, a second control command is sent to the evaporator bypass circuit, evaporator circuit, high temperature molten salt circuit and low temperature molten salt circuit. The second control command is used to stop the high-temperature molten salt circuit from supplying high-temperature molten salt. In addition, controlling the cryogenic molten salt circuit to increase the cryogenic molten salt delivery rate. Additionally, the evaporator bypass circuit is activated so that the mixed molten salt does not pass through the evaporator circuit but flows directly back to the low-temperature molten salt circuit via the evaporator bypass circuit.

2. The graded early warning system for internal leakage of a steam generator according to claim 1, characterized in that, The control device acquires first moisture concentration data in real time, and based on the first moisture concentration data at each sampling time and a pre-set early leakage warning strategy, when an early leakage is determined, acquires first temperature data and second temperature data in real time, including: First moisture concentration data is acquired in real time based on a pre-set first sampling frequency. When the first moisture concentration data at any sampling moment exceeds a pre-set first moisture concentration threshold, the first moisture concentration data at all sampling moments within a first preset time period in the future are recorded to obtain the corresponding first moisture concentration sequence. Based on the first moisture concentration threshold and the first moisture concentration data at each sampling moment in the first moisture concentration sequence, the first moisture concentration exceeding the limit ratio corresponding to the first moisture concentration sequence is determined. The first moisture concentration exceeding the limit ratio is the proportion of the number of first moisture concentration data exceeding the first moisture concentration threshold in the first moisture concentration sequence to the total number of first moisture concentration data in the first moisture concentration sequence. When it is determined that the proportion of the first moisture concentration exceeding the limit is greater than the preset proportion threshold, the rate of change of the first moisture concentration corresponding to the first moisture concentration sequence is determined based on all the first moisture concentration data in the first moisture concentration sequence. When the rate of change of the first moisture concentration corresponding to the first moisture concentration sequence is greater than 0, the first sampling frequency is increased to the preset second sampling frequency. At the same time, the first temperature data and the second temperature data are acquired in real time based on the second sampling frequency.

3. The graded early warning system for internal leakage of a steam generator according to claim 1, characterized in that, The control device, based on the first temperature data, second temperature data, and first moisture concentration data at each sampling time after the early leakage, and a pre-set leakage development early warning strategy, determines that leakage development exists, and then sends a first control command to the high-temperature molten salt circuit, the evaporator circuit, and the low-temperature molten salt circuit, including: Based on the first moisture concentration data at each sampling time after the early leakage, the second moisture concentration sequence corresponding to each sampling time after the early leakage is obtained; and based on the second moisture concentration sequence corresponding to each sampling time after the early leakage, the rate of change of the second moisture concentration corresponding to each sampling time after the early leakage is obtained; the second moisture concentration sequence corresponding to any sampling time after the early leakage includes the first moisture concentration data corresponding to multiple consecutive sampling times, including that sampling time. Based on the first temperature data at each sampling time after the early leakage, the first temperature sequence corresponding to each sampling time after the early leakage is obtained; and based on the first temperature sequence corresponding to each sampling time after the early leakage, the first temperature change rate corresponding to each sampling time after the early leakage is obtained; the first temperature sequence corresponding to any sampling time after the early leakage includes the first temperature data corresponding to multiple consecutive sampling times, including that sampling time. Based on the first and second temperature data at each sampling time after the early leakage, the evaporator inlet and outlet temperature difference at each sampling time after the early leakage is obtained. Based on the first moisture concentration data, the second moisture concentration change rate, the first temperature change rate, and the evaporator inlet and outlet temperature difference at each sampling moment after the early leakage, as well as the pre-set leakage development early warning strategy, when it is determined that leakage is developing, the first control command is sent to the high-temperature molten salt circuit, the evaporator circuit, and the low-temperature molten salt circuit.

4. The graded early warning system for internal leakage of a steam generator according to claim 3, characterized in that, The leak development early warning strategy includes: When the rate of change of the second moisture concentration at any sampling time after an early leak exceeds the preset threshold for the rate of change of the first moisture concentration, it is determined that a leak has developed. Alternatively, if the first temperature change rate at any sampling time after an early leak is within a preset first temperature change rate range, and the first moisture concentration data at that sampling time is greater than a preset second moisture concentration threshold, then a leak is determined to have developed; wherein the second moisture concentration threshold is greater than the first moisture concentration threshold. Alternatively, if the temperature difference between the evaporator inlet and outlet at any sampling time after an early leak is greater than a pre-set first temperature threshold, it is determined that a leak has developed.

5. The graded early warning system for internal leakage of a steam generator according to claim 1, characterized in that, The control device, based on the first pressure data, first temperature data, second temperature data, and first moisture concentration data at each sampling moment after the leakage develops, and a pre-set severe internal leakage early warning strategy, determines whether a severe internal leak exists, including: Based on the first temperature data at each sampling time after the leakage develops, a second temperature sequence corresponding to each sampling time after the leakage develops is obtained; and based on the second temperature sequence corresponding to each sampling time after the leakage develops, the second temperature change rate corresponding to each sampling time after the leakage develops is obtained; the second temperature sequence corresponding to any sampling time after the leakage develops includes the first temperature data corresponding to multiple consecutive sampling times, including that sampling time. Based on the first pressure data at each sampling time after the leakage develops, the first pressure sequence corresponding to each sampling time after the leakage develops is obtained; and based on the first pressure sequence corresponding to each sampling time after the leakage develops, the first pressure change rate corresponding to each sampling time after the leakage develops is obtained; the first pressure sequence corresponding to any sampling time after the leakage develops includes the first pressure data corresponding to multiple consecutive sampling times, including that sampling time. Based on the first pressure change rate, second temperature change rate, and first moisture concentration data at each sampling moment after the leakage develops, as well as the pre-set serious internal leakage early warning strategy, it is determined whether a serious internal leakage exists.

6. The graded early warning system for internal leakage of a steam generator according to claim 5, characterized in that, The critical internal leakage early warning strategy includes: When the second temperature change rate at any sampling moment after the leakage has developed is less than the preset first temperature change rate threshold, it is determined that there is a serious internal leak. Alternatively, if the rate of change of the first pressure at any sampling moment after the leakage has developed exceeds a preset rate of change of pressure threshold, a serious internal leak is determined to exist. Alternatively, if the first moisture concentration data at any sampling time after the leak has developed is greater than the pre-set third moisture concentration threshold, a serious internal leak is determined to exist.

7. The graded early warning system for internal leakage of a steam generator according to claim 1, characterized in that, The first inlet of the salt mixing tank is connected to the high-temperature molten salt circuit, and the outlet and second inlet of the salt mixing tank are both connected to the low-temperature molten salt circuit. The evaporator circuit and the evaporator bypass circuit are set on the connecting pipe between the outlet of the salt mixing tank and the low-temperature molten salt circuit, and the evaporator circuit and the evaporator bypass circuit are set in parallel. A first temperature sensor, a first pressure transmitter and a first moisture analyzer are set on the connecting pipe between the evaporator circuit and the low-temperature molten salt circuit, and a second temperature sensor is set on the connecting pipe between the outlet of the salt mixing tank and the evaporator circuit. The first moisture analyzer is used to acquire first moisture concentration data, the first temperature sensor is used to acquire first temperature data, the second temperature sensor is used to acquire second temperature data, and the first pressure transmitter is used to acquire first pressure data in real time. The first pressure transmitter, the first moisture analyzer, the first temperature sensor, and the second temperature sensor are all connected to the control device.

8. The graded early warning system for internal leakage of a steam generator according to claim 7, characterized in that, The cryogenic molten salt circuit includes a cryogenic molten salt tank, a cryogenic molten salt pump, and a cryogenic molten salt regulating valve; the high-temperature molten salt circuit includes a high-temperature molten salt tank and a high-temperature molten salt pump; the evaporator circuit includes an evaporator and a feedwater regulating valve. The inlet of the low-temperature molten salt tank and the outlet of the mixing salt tank are connected through a first pipeline. The evaporator, the first moisture analyzer, the first temperature sensor and the second temperature sensor are all installed on the first pipeline. The first moisture analyzer and the first temperature sensor are installed on the first pipeline between the evaporator and the low-temperature molten salt tank, and the second temperature sensor is installed on the first pipeline between the evaporator and the outlet of the mixing salt tank. The outlet of the cryogenic molten salt tank and the second inlet of the mixing tank are connected by a second pipeline. The cryogenic molten salt pump is installed on the second pipeline and is used to transport cryogenic molten salt from the cryogenic molten salt tank to the mixing tank. The cryogenic molten salt regulating valve is installed on the second pipeline and is located between the cryogenic molten salt pump and the mixing tank. The outlet of the high-temperature molten salt tank is connected to the first inlet of the mixing salt tank through a third pipeline. The high-temperature molten salt pump is installed on the third pipeline and is used to transport high-temperature molten salt from the high-temperature molten salt tank to the mixing salt tank. The evaporator is supplied with water from the outside through a pre-deployed water supply pipe, and the water supply regulating valve is installed on the water supply pipe; The water supply regulating valve, the cryogenic molten salt pump, the cryogenic molten salt regulating valve, and the high-temperature molten salt pump are all connected to the control device; When the control device determines that a leak is developing, it sends a first control command to the high-temperature molten salt circuit, the evaporator, and the low-temperature molten salt circuit, including: When a leak is confirmed to be developing, a first control command is sent to the water supply regulating valve, the cryogenic molten salt pump, the cryogenic molten salt regulating valve, and the high-temperature molten salt pump; The first control command is used to: control the high-temperature molten salt pump to reduce its power to a preset level to reduce the molten salt delivery flow rate; control the low-temperature molten salt regulating valve to a first preset opening level to control the ratio of the molten salt delivery flow rates of the low-temperature molten salt circuit and the high-temperature molten salt circuit; and control the feedwater regulating valve to a second preset opening level to reduce the feedwater flow rate entering the evaporator.

9. The graded early warning system for internal leakage of a steam generator according to claim 8, characterized in that, The evaporator circuit also includes an evaporator brine trap, an evaporator molten salt outlet valve, and an evaporator molten salt inlet valve; the high-temperature molten salt circuit also includes a high-temperature molten salt regulating valve; the evaporator bypass circuit is an evaporator bypass valve; Specifically, the first position between the evaporator bypass valve and the salt mixing tank is connected to the molten salt inlet of the evaporator through a fourth pipeline, and the second position between the evaporator bypass valve and the low-temperature molten salt tank is connected to the molten salt outlet of the evaporator through a fifth pipeline; the molten salt inlet valve is located on the fourth pipeline, and the molten salt outlet valve is located on the fifth pipeline; the evaporator's salt outlet is connected to the low-temperature molten salt tank's salt outlet through a sixth pipeline, and the evaporator's salt outlet valve is located on the sixth pipeline; The high-temperature molten salt valve is installed on the third pipeline and is located between the high-temperature molten salt pump and the mixing tank; The high-temperature molten salt valve, evaporator desalination valve, evaporator molten salt outlet valve, and evaporator molten salt inlet valve are all connected to the control device. When a serious internal leak is detected, the control device sends a second control command to the evaporator bypass valve, the evaporator circuit, the high-temperature molten salt circuit, and the low-temperature molten salt circuit, including: When a serious internal leak is detected, a fourth control command is sent to the evaporator bypass valve, the evaporator molten salt outlet valve, and the evaporator molten salt inlet valve to fully open the evaporator bypass valve while closing the evaporator molten salt outlet valve and the evaporator molten salt inlet valve. In addition, a fifth control command is sent to the high-temperature molten salt pump to stop the high-temperature molten salt pump and at the same time cause the residual molten salt in the high-temperature molten salt pump to flow back to the high-temperature molten salt tank; In addition, a sixth control command is sent to the low-temperature molten salt regulating valve and the high-temperature molten salt regulating valve to fully open the low-temperature molten salt regulating valve while closing the high-temperature molten salt regulating valve; In addition, a seventh control command is sent to the water supply regulating valve to reduce the water supply regulating valve to the third preset opening degree; And, after sending the sixth control command, at a second preset time, an eighth control command is sent to the evaporator desalination valve to fully open the evaporator desalination valve.

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