Method and device for preheating a molten salt tank collector

Abstract

The present application relates to the technical field of collector control, and particularly relates to a molten salt tank type collector preheating control method and device, which comprises the following steps: before starting the heat collection system, based on the molten salt injection characteristics, determining the initial preheating execution parameters of each collector, and using the initial preheating execution parameters to control the corresponding heating components to perform initial heating on the collector; during the injection process, real-time monitoring the state difference vectors of each collector; the state difference vector represents the difference of each state parameter between the input end and the output end of the collector; the state difference vector includes temperature difference, pressure difference and flow difference; in response to the difference of any state parameter exceeding the corresponding preset fluctuation range, inputting the state difference vector into the preset preheating adjustment model to obtain a preheating adjustment factor; based on the preheating adjustment factor, modifying the initial preheating execution parameters to obtain real-time preheating execution parameters, and using the real-time preheating execution parameters to control the corresponding heating components to perform real-time heating on the collector. The present application can improve the system stability.

Description

Technical Field

[0001] This invention relates to the technical field of solar collector control, and more particularly to a preheating control method and apparatus for a molten salt trough solar collector. Background Technology

[0002] Molten salt trough solar collectors, as a highly efficient solar thermal utilization device, play an important role in solar thermal power generation systems. Their working principle involves focusing sunlight onto the collector, causing the molten salt to absorb heat and convert light energy into thermal energy, thus providing a high-temperature heat source for subsequent power generation or heating processes.

[0003] Existing preheating control methods for molten salt trough solar collectors mostly employ uniform power heating or control based on a single temperature threshold. They only trigger preheating stop by setting a fixed temperature target (such as 260°C), without setting targeted initial preheating parameters based on the structural differences of different solar collectors. Furthermore, during molten salt injection, they cannot adjust the heating strategy in real time based on fluctuations in the state parameters at the input and output ends. For example, when the temperature at the output end of the solar collector meets the target but the flow rate drops sharply due to local blockage, existing control methods cannot identify the potential freezing risk in time, which can lead to problems such as local freezing of pipelines, abnormal pressure increases, or even valve jamming. Summary of the Invention

[0004] This invention provides a preheating control method and device for molten salt trough solar collectors that can improve system stability and reduce the risk of failure, and can effectively solve the problems in the background art.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a preheating control method for a molten salt trough solar collector, comprising:

[0006] Before the solar collector system is started, the initial preheating execution parameters of each solar collector are determined based on the molten salt injection characteristics, and the corresponding heating components are used to control the initial heating of the solar collector.

[0007] During the injection process, the state difference vector corresponding to each collector is monitored in real time; the state difference vector represents the difference of various state parameters between the input and output ends of the collector; the state difference vector includes temperature difference, pressure difference and flow rate difference;

[0008] In response to any state parameter difference exceeding the corresponding preset fluctuation range, the state difference vector is input into the preset preheating adjustment model to obtain the preheating adjustment factor.

[0009] The initial preheating execution parameters are corrected based on the preheating adjustment factor to obtain real-time preheating execution parameters, and the corresponding heating components are used to control the real-time heating of the solar collector.

[0010] In conjunction with the first aspect, in one possible design, before the solar collector system is started, the initial preheating execution parameters for each collector are determined based on the molten salt injection characteristics, including:

[0011] Acquire molten salt injection characteristics and multiple sets of collector status characteristics; the multiple sets of collector status characteristics correspond to multiple collectors in the solar collector system, wherein each collector is equipped with a set of heating components;

[0012] Based on the molten salt injection characteristics, and combined with the collector status characteristics of each collector, the freezing and blockage risk assessment of each collector is carried out to obtain the freezing and blockage risk index corresponding to each collector.

[0013] For each solar collector, the initial preheating execution parameters corresponding to that heating component are obtained by mapping the corresponding freezing and blockage risk index and the performance parameters of its heating component in a preset preheating strategy library.

[0014] In conjunction with the first aspect, in one possible design, the molten salt injection characteristics include molten salt injection temperature, molten salt injection pressure, and molten salt solidification point.

[0015] In conjunction with the first aspect, in one possible design, the collector state characteristics include pipe length, pipe inner diameter, and initial pipe temperature.

[0016] In conjunction with the first aspect, in one possible design, the performance parameters of the heating component include at least maximum heating power, heating efficiency, temperature control accuracy, and response time.

[0017] In conjunction with the first aspect, in one possible design, the strategies in the preset preheating strategy library include a phased preheating strategy, a dynamically adjusted preheating strategy, and a safety redundancy preheating strategy.

[0018] In conjunction with the first aspect, in one possible design, the preset fluctuation range is set based on the physical property parameters of the molten salt itself, the limits of the collector structure and operating parameters, historical operating data and experimental verification results, the performance of the heating components and the system safety redundancy.

[0019] In conjunction with the first aspect, the initial preheating execution parameters include at least heating power, heating voltage, target temperature, and heating duration.

[0020] In conjunction with the first aspect, both the input and output ends of the solar collector are equipped with temperature sensors, flow sensors, and pressure sensors.

[0021] On the other hand, the present invention also provides a preheating control device for a molten salt trough solar collector, comprising:

[0022] Support mechanism, used to provide insulating support for the metal tubes of the solar collector;

[0023] The initial preheating execution module is used to determine the initial preheating execution parameters of each collector based on the molten salt injection characteristics before the solar collector system is started, and to control the corresponding heating components to perform initial heating on the collector.

[0024] The state difference monitoring module is used to collect and calculate the state difference vector between the input and output ends of each collector in real time during the molten salt injection process. The state difference vector includes at least temperature difference, pressure difference and flow rate difference.

[0025] The preheating adjustment calculation module is used to input the state difference vector into the preheating adjustment model and output the preheating adjustment factor when the difference of any state parameter exceeds its corresponding preset fluctuation range.

[0026] The real-time preheating execution module is used to correct the initial preheating execution parameters according to the preheating adjustment factor, generate real-time preheating execution parameters, and control the corresponding heating components to heat the collector in real time.

[0027] In conjunction with the second aspect, the support mechanism includes at least a drive bracket and a clamp bracket;

[0028] The drive bracket is provided with a first insulating component to achieve insulation between the drive bracket and the metal tube of the solar collector.

[0029] The clamp bracket is provided with a second insulation component to achieve insulation between the clamp bracket and the metal tube of the solar collector.

[0030] Both the first insulating component and the second insulating component are made of insulating material.

[0031] In conjunction with the second aspect, the first insulating component includes at least an insulating pad, an insulating bolt sleeve, and an insulating gasket;

[0032] The insulating pad is installed between the top seat of the drive bracket and the base of the bracket;

[0033] The insulating bolt sleeve is adapted to the screw of the drive bracket and is sleeved on the outside of the screw;

[0034] The insulating gasket is placed on the nut side of the drive bracket.

[0035] In conjunction with the second aspect, the second insulation assembly includes at least a thermal insulation component, an insulating sleeve, and an insulating sleeve group;

[0036] The inner diameter of the heat insulation component is the same as the outer diameter of the collector metal tube, the width is the distance between two adjacent collector metal tubes, and it is fixed to the collector metal tube by a clamp structure.

[0037] The insulating sleeve is fitted onto the outside of the pin of the clamp bracket;

[0038] The insulating sleeve is installed at the spring plate of the clamp bracket.

[0039] The technical solution of this invention can achieve the following technical effects:

[0040] Before the solar collector system is started, the initial preheating parameters for each collector are determined based on the molten salt injection characteristics, and the corresponding heating components are controlled to perform initial heating. Individual differences among collectors are considered, making the initial preheating more closely reflect actual conditions and helping to improve preheating effect and efficiency. During the injection process, the state difference vector corresponding to each collector is monitored in real time. This vector covers the temperature difference, pressure difference, and flow rate difference between the input and output ends of the collector. By comprehensively monitoring the differences of these key state parameters, changes in the collector's operating status can be promptly grasped. When the difference of any state parameter exceeds the corresponding preset fluctuation range, the state difference vector is input into the preset preheating adjustment model, enabling timely detection. If the collector output temperature meets the standard but the flow rate drops suddenly due to local blockage, the system effectively identifies potential freezing risks and avoids serious consequences such as localized pipe freezing, abnormal pressure increases, or even valve jamming, which are difficult to detect in time with existing control methods. Based on the preheating adjustment factor obtained from the preheating adjustment model, the initial preheating execution parameters are corrected to obtain real-time preheating execution parameters, which are then used to control the corresponding heating components to heat the collector in real time. This allows the heating strategy to be dynamically adjusted according to the actual operating status of the collector, improving the flexibility and accuracy of control, ensuring that the collector maintains a good preheating effect under different operating conditions, and guaranteeing the stable operation of the entire solar thermal power generation system. Attached Figure Description

[0041] Figure 1 This is a flowchart of the present invention;

[0042] Figure 2 Diagram of the heating circuit for a molten salt bath system;

[0043] Figure 3 Heating circuit diagram for a molten salt trough solar collector system;

[0044] Figure 4 This is a schematic diagram of the drive bracket structure;

[0045] Figure 5 This is a schematic diagram of the clamp support structure;

[0046] Figure 6 This is a schematic diagram of the insulating sleeve.

[0047] The following are labeled in the attached diagram: 1. Frame bracket; 2. Spring plate; 3. Bottom support; 4. Heat collector tube clamp fastener; 5. Heat collector tube; 6. Clamp support pin; 7. Thermal insulation component; 8. Insulating sleeve; 9. Insulating sleeve assembly; 11. Bracket top seat; 12. Bracket base; 13. Transition metal pipe; 14. Bolt hole; 15. Insulating pad; 16. Insulating gasket; 17. Insulating bolt sleeve. Detailed Implementation

[0048] This application will now be described with reference to the accompanying drawings.

[0049] like Figure 2 As shown, the vacuum collector tubes arranged inside the main body of the solar collector focus sunlight to provide a basic heat exchange structure for molten salt heating. The directions of the molten salt inlet and outlet are marked. Molten salt flows into the solar collector from the inlet, is heated and flows out from the outlet, realizing the conversion and transfer of light energy to heat energy.

[0050] F1 and F2 are flow sensors, T1 and T2 are temperature sensors, and P1 and P2 are pressure sensors;

[0051] Solar energy is collected by a parabolic trough collector to heat molten salt. Sensors monitor the state parameters of the molten salt in real time, and the operation of the collector is regulated by a control system to ensure that the molten salt circulates at appropriate temperature, flow rate and pressure, providing a stable high-temperature heat source for subsequent power generation or heating processes.

[0052] The solar collector's main body features a rationally arranged array of vacuum collector tubes. By focusing sunlight, it establishes a basic heat exchange structure for molten salt heating, efficiently converting abundant solar energy into thermal energy. The molten salt absorbs this heat, providing a high-temperature heat source for subsequent power generation or heating, thus improving the utilization efficiency of solar energy. The inclusion of flow, temperature, and pressure sensors enables real-time and accurate monitoring of key parameters such as molten salt flow rate, temperature, and pressure. This helps to promptly understand the molten salt's operating status within the collector, providing data support for stable system operation. The control system adjusts the collector's operation based on real-time data from the sensors, ensuring the molten salt circulates at suitable temperature, flow rate, and pressure. This effectively prevents system failures caused by abnormal parameters, ensuring long-term stable operation of the collector and reducing equipment damage risks and maintenance costs. Through this process of photothermal conversion, monitoring, and control, a stable high-temperature heat source is provided for subsequent power generation or heating, guaranteeing the reliability and stability of the solar thermal power generation or heating system and improving the overall quality of energy supply.

[0053] like Figure 3As shown, the molten salt trough solar collector system includes four collector units. Molten salt enters the collector from a low-temperature pipe, is heated by the vacuum collector tube to become high-temperature molten salt, and flows out from the high-temperature pipe, realizing the conversion and transfer of light energy to heat energy. The collector R is made of stainless steel metal tube. A terminal is led out from the drive bracket in the middle of the collector group and connected to the positive terminal of the DC power supply G. Terminals are led out at both ends of the collector group's heat collection circuit and connected to the negative terminal of the DC power supply, and are simultaneously grounded. By passing DC power to the collector group's heat collection circuit, the heat is generated by the metal's own resistance. At the same time, the main pipeline or other heat collection circuits are shielded by the grounding devices at both ends.

[0054] Low-temperature molten salt enters the system through the low-temperature molten salt pipe on the left and begins to circulate within the system under the regulation of valve FM1. The low-temperature molten salt flows sequentially through heat collection units SCA1, SCA2, SCA3, and SCA4. In each heat collection unit, vacuum heat collection tubes focus sunlight, converting solar energy into heat energy to heat the flowing molten salt, gradually increasing its temperature. After continuous heating by multiple heat collection units, the molten salt becomes high-temperature molten salt and finally flows out of the system through the high-temperature molten salt pipe on the right, providing a high-temperature heat source for subsequent power generation or heating processes. The molten salt trough heat collection system monitors the molten salt status parameters in real time through sensors, and the control elements adjust the valve opening and heat collection tube angle in a timely manner based on these parameters to ensure that the molten salt circulates in optimal condition, improving the photothermal conversion efficiency.

[0055] Among them, T1 and T2 serve as temperature sensors at the beginning and end of the collector group loop, F1 and F2 as flow sensors at the beginning and end of the collector group loop, and P1 and P2 as pressure sensors at the beginning and end of the collector group loop. The combined judgment of each set of sensors is used to control the preheating and defrosting control of the loop. Valves FM1 and FM6 are used to isolate the collectors from the main pipeline. Valves FM2, FM3, FM4, and FM5 are used for emergency salt discharge of the collector group.

[0056] The system is equipped with four solar collector units. Low-temperature molten salt flows through each unit sequentially, and the vacuum collector tubes within effectively focus sunlight, efficiently converting solar energy into heat energy to continuously heat the molten salt. The final output is high-temperature molten salt, providing a sufficient and stable high-temperature heat source for subsequent power generation or heating, greatly improving the utilization efficiency of solar energy. Sensors monitor the flow rate, temperature, pressure, and other status parameters of the molten salt in real time, enabling timely and accurate understanding of the molten salt's operating status within the system. This provides reliable data support for stable operation and precise control. The control components adjust valve openings and collector tube angles promptly based on sensor feedback, ensuring the molten salt circulates under optimal temperature, flow rate, and pressure conditions. This effectively avoids system failures caused by abnormal parameters and guarantees long-term stable operation. Through the synergistic effect of photothermal conversion, status monitoring, and intelligent control, the system maintains efficient and stable operation under different working conditions, improving photothermal conversion efficiency and reducing maintenance costs.

[0057] like Figure 1 As shown, the preheating control method for the molten salt trough solar collector of the present invention specifically includes the following steps:

[0058] S1. Before the solar collector system is started, based on the characteristics of molten salt injection, the initial preheating execution parameters of each solar collector are determined, and the corresponding heating components are used to control the initial heating of the solar collector.

[0059] S2. During the injection process, the state difference vector corresponding to each collector is monitored in real time; the state difference vector represents the difference between various state parameters between the input and output ends of the collector.

[0060] S3. In response to the difference of any state parameter exceeding the corresponding preset fluctuation range, the state difference vector is input into the preset preheating adjustment model to obtain the preheating adjustment factor.

[0061] S4. Based on the preheating adjustment factor, the initial preheating execution parameters are corrected to obtain real-time preheating execution parameters, and the corresponding heating components are used to control the solar collector to heat it in real time.

[0062] In this embodiment, before the solar collector system is started, the initial preheating execution parameters of each solar collector are determined based on the molten salt injection characteristics, and the corresponding heating components are controlled to perform initial heating. The individual differences of the solar collectors are taken into account, making the initial preheating more in line with the actual situation, which helps to improve the preheating effect and efficiency.

[0063] During the injection process, the state difference vector corresponding to each collector is monitored in real time. This vector covers the temperature difference, pressure difference, and flow difference between the input and output ends of the collector. By comprehensively monitoring the differences of these key state parameters, the changes in the operating status of the collector can be grasped in a timely manner.

[0064] When the difference of any state parameter exceeds the corresponding preset fluctuation range, the state difference vector is input into the preset preheating regulation model, which can promptly detect abnormal situations such as the collector output temperature meeting the standard but the flow rate dropping suddenly due to local blockage. It can effectively identify potential freezing risks and avoid serious consequences such as local freezing of pipelines, abnormal pressure rise, or even valve jamming caused by the difficulty of timely detection of such problems by existing control methods.

[0065] The preheating adjustment factor obtained from the preheating adjustment model is used to correct the initial preheating execution parameters to obtain real-time preheating execution parameters. These parameters are then used to control the corresponding heating components to heat the solar collector in real time. This allows the heating strategy to be dynamically adjusted according to the actual operating status of the solar collector, improving the flexibility and accuracy of control. It ensures that the solar collector maintains a good preheating effect under different operating conditions, thus guaranteeing the stable operation of the entire solar thermal power generation system.

[0066] In some embodiments of the present invention, for step S1, before the solar collector system is started, the initial preheating execution parameters of each solar collector are determined based on the molten salt injection characteristics, and the corresponding heating components are controlled to perform initial heating of the solar collector accordingly.

[0067] Acquire molten salt injection characteristics and multiple sets of collector status characteristics;

[0068] Molten salt injection characteristics include molten salt injection temperature, molten salt injection pressure, and molten salt freezing point;

[0069] The molten salt injection temperature reflects the initial thermal state of the molten salt when it enters the solar collector system. The flow and heat transfer characteristics of molten salt at different temperatures will be different in the solar collector. A lower injection temperature means that stronger initial heating is required to prevent the molten salt from solidifying too early in the pipeline, while a higher injection temperature reduces the burden of initial heating to some extent.

[0070] Molten salt injection pressure affects the flow rate and distribution of molten salt in the pipeline; higher injection pressure can make molten salt fill the pipeline more quickly, but at the same time, it will place higher demands on the pipeline's sealing and strength; during the preheating process, appropriate injection pressure helps to ensure that the molten salt is heated evenly and avoids local overheating or undercooling.

[0071] The freezing point of molten salt is the critical temperature at which molten salt changes from a liquid to a solid state. In preheating control, it is essential to ensure that the temperature inside the solar collector is always higher than the freezing point of molten salt to prevent the molten salt from solidifying and causing pipeline blockage.

[0072] The multiple sets of collector state characteristics correspond to multiple collectors in the solar collector system, wherein each collector is equipped with a set of heating components; the collector state characteristics include pipe length, pipe inner diameter, and pipe initial temperature;

[0073] Longer pipes mean that the molten salt stays in the collector for a longer time and the heat transfer process is more complex. Longer pipes also require longer preheating time and higher heating power to ensure that the molten salt in the entire pipe reaches the appropriate temperature.

[0074] The inner diameter of the pipe affects the flow cross-sectional area and flow velocity of the molten salt; a smaller inner diameter will lead to a faster flow velocity of the molten salt, but may also increase flow resistance and affect heat transfer efficiency; during the preheating process, the heating power needs to be adjusted reasonably according to the inner diameter of the pipe to ensure that the molten salt can be heated evenly.

[0075] The initial temperature of the pipeline reflects the thermal state of the solar collector before startup. If the initial temperature of the pipeline is low, it means that the solar collector needs more heat for preheating, and the initial heating power may need to be increased accordingly. Conversely, if the initial temperature of the pipeline is high, the initial heating power can be appropriately reduced to save energy.

[0076] Based on the molten salt injection characteristics, and combined with the collector status characteristics of each collector, the freezing and blockage risk assessment of each collector is carried out to obtain the freezing and blockage risk index corresponding to each collector.

[0077] The problem of freezing and blockage risk assessment is divided into three layers: target layer, criterion layer, and indicator layer. The target layer is the assessment of freezing and blockage risk; the criterion layer includes two aspects: molten salt injection characteristics and collector condition characteristics; and the indicator layer consists of specific characteristic parameters.

[0078] Pairwise comparisons are made between factors at each level to determine their relative importance weights. For example, in the criterion level, the impact of molten salt injection characteristics and collector condition characteristics on the risk of freezing is compared and assigned corresponding weights. In the indicator level, pairwise comparisons are made between each characteristic parameter to determine its weight in the criterion level to which it belongs.

[0079] Based on the actual values ​​of each feature parameter, they are divided into different evaluation levels. Then, the frequency of each feature parameter belonging to each evaluation level is counted to construct a fuzzy evaluation matrix.

[0080] The weights and fuzzy evaluation matrix are combined to obtain the freezing and blockage risk index.

[0081] The performance parameters of the heating components should include at least the maximum heating power, heating efficiency, temperature control accuracy, and response time.

[0082] Maximum heating power indicates the maximum heat power that the heating element can provide, which directly affects the preheating speed.

[0083] Heating efficiency indicates how efficiently a heating element converts electrical energy into heat energy; high efficiency means less energy loss.

[0084] Temperature control accuracy indicates the ability of a heating component to precisely control the heating temperature.

[0085] Response time represents the time from when the heating component receives a heating command to when it actually starts heating. A fast response helps to adjust the preheating strategy in a timely manner.

[0086] The preheating strategy library includes a variety of preheating strategies, each optimized for specific freeze-blocking risk indices and heating component performance parameters. The strategies in the library include:

[0087] The phased preheating strategy divides the preheating process into multiple stages based on the level of the freezing blockage risk index, with different heating power and temperature targets set for each stage.

[0088] The preheating strategy is dynamically adjusted. During the preheating process, the heating power and temperature target are dynamically adjusted based on the real-time monitored collector status parameters.

[0089] The safety redundancy preheating strategy sets a higher heating power and temperature margin than normal requirements to prevent unexpected situations, ensuring safe preheating even under extreme conditions.

[0090] In this embodiment, by accurately assessing the freezing risk index of each collector, differentiated preheating strategies can be adopted for collectors with different risk levels, effectively avoiding local freezing or overheating caused by uniform preheating parameters, thereby improving the operational safety and reliability of the entire solar collector system. Customizing preheating parameters based on the actual state characteristics of the collectors and the molten salt injection characteristics ensures precise matching of heating power with collector requirements, avoiding energy waste. By introducing the performance parameters of the heating components and selecting the most suitable preheating strategy from a preset preheating strategy library, the heating components can operate in optimal condition, quickly responding to changes in preheating demand, shortening preheating time, and improving overall preheating efficiency. The preset preheating strategy library contains various optimization strategies for different freezing risk indices and heating component performance parameters, enabling the system to flexibly adjust the preheating scheme according to actual conditions, adapting to preheating needs under different operating conditions, and improving the system's adaptability and flexibility. Precise control of the preheating process reduces equipment damage and maintenance needs caused by freezing or overheating, thereby reducing operation and maintenance costs. Simultaneously, personalized preheating strategies help extend equipment lifespan, improving the overall economy and reliability of the system.

[0091] In some embodiments of the present invention, for step S2, during the injection process, the state difference vector corresponding to each collector is monitored in real time; the state difference vector represents the difference between various state parameters between the input and output ends of the collector.

[0092] The state difference vector includes temperature difference, pressure difference, and flow rate difference;

[0093] High-precision temperature sensors, flow sensors, and pressure sensors are installed at the input and output ends of the solar collector, respectively; the sensors accurately measure the temperature, flow rate, and pressure of the molten salt.

[0094] At the input end of the solar collector, a temperature sensor captures the temperature of the molten salt entering the collector in real time, a pressure sensor accurately measures the pressure of the molten salt, and a flow sensor records the inflow rate of the molten salt. At the output end, sensors also monitor the state parameters of the molten salt flowing out of the solar collector.

[0095] Taking temperature parameters as an example, during the molten salt injection process, if the heat transfer inside the collector is normal and there is no local blockage or abnormal heat exchange, the temperature at the input and output ends should show a reasonable trend, and the difference between the two should be within a stable range. Once a local blockage occurs, heat transfer is hindered, which may cause the output temperature to drop abnormally, and the temperature difference between the output and input ends to exceed the preset fluctuation range. The same applies to pressure parameters. Under normal circumstances, the pressure difference between the two ends of the collector should be maintained within a specific range to ensure the stable flow of molten salt. If the output pressure rises sharply due to blockage or other reasons, causing the pressure difference to exceed the preset range, this is the warning signal issued by the system. Flow parameters are equally critical. When there is a problem inside the collector, the flow rate at the output end may decrease sharply, and the difference between the flow rate at the input end will increase, deviating from the normal fluctuation range.

[0096] Data from each sensor is collected periodically, and the difference between the corresponding parameters at the input and output ends is calculated to obtain the state difference vector.

[0097] In this embodiment, relying on sensors configured at the input and output ends of the solar collector, temperature, pressure, and flow data are collected in real time and the differences are calculated. This directly reflects the flow and heat transfer state of molten salt within the solar collector, enabling early identification of potential freezing risks and abnormal operating conditions. Given the characteristics of molten salt being prone to solidification and requiring continuous monitoring, data collection and difference calculation at regular intervals dynamically track the state changes of the molten salt during flow, overcoming the limitations of existing technologies that rely solely on fixed temperatures. The state difference vector provides direct input parameters for subsequent steps. When any difference exceeds a preset range, an adjustment mechanism is triggered, ensuring that the heating strategy can be dynamically adjusted according to the real-time state. This avoids problems such as freezing and pressure anomalies caused by undetected local anomalies, ensuring the safety and stability of the solar collector injection process.

[0098] In some embodiments of the present invention, for step S3, in response to the difference of any state parameter exceeding the corresponding preset fluctuation range, the state difference vector is input into a preset preheating adjustment model to obtain a preheating adjustment factor.

[0099] The preset fluctuation range is set based on the following criteria:

[0100] The physical properties of molten salt itself are considered. Molten salt thawing requires continuous heating within a certain temperature range, and the temperature must be kept below the freezing point to avoid freezing blockage. Therefore, the preset fluctuation range of the temperature difference should be based on the freezing point of molten salt to ensure that the temperature inside the collector is always higher than the freezing point. At the same time, the influence of the viscosity and fluidity changes of molten salt at different temperatures on heat transfer and flow should be considered.

[0101] The limits of the collector's structure and operating parameters are based on the collector's piping design parameters, including pipe length, inner diameter, and material. Pipe length and inner diameter determine the flow resistance and residence time of molten salt within the collector. Shorter pipes have lower pressure loss, and the pressure difference fluctuation range must be adapted to their flow characteristics. For longer pipes, the normal pressure difference range needs to be wider to accommodate natural resistance differences. The collector's design pressure-bearing capacity limits the upper limit of pressure difference fluctuations to prevent excessive pressure differences from exceeding the pipe's strength and causing leakage or damage.

[0102] Historical operating data and experimental verification results: Based on historical operating data of similar solar collectors under different operating conditions, the fluctuation range of temperature difference, pressure difference, and flow difference during normal operation is statistically analyzed; during normal salt injection without freezing or local blockage, the range of parameter differences between the input and output ends is recorded through a large number of experiments, which serves as the basis for the preset fluctuation range.

[0103] The performance of the heating components and the safety redundancy of the system should be considered, taking into account the maximum heating power, temperature control accuracy, and other performance parameters of the heating components. For heating components with low temperature control accuracy, the fluctuation range of temperature difference should be appropriately widened to avoid misjudgment due to equipment errors. At the same time, safety redundancy should be reserved, such as setting the upper limit of the pressure difference to be lower than 80% of the collector's burst pressure to ensure system safety in extreme situations.

[0104] The main task of the preheating adjustment model is to determine the corresponding preheating adjustment factor based on the input state difference vector; the preheating adjustment factor is a correction amount for the initial preheating execution parameters, which helps to optimize the heating strategy.

[0105] Once the state difference vector is input, the adjustment model will generate a preheating adjustment factor based on the previously trained pattern. The preheating adjustment factor represents the degree of correction of the current collector state. When the state difference is large, the adjustment factor will be increased to enhance the preheating intensity, ensure more uniform and rapid heating, and avoid the risk of freezing due to excessively low temperature or local blockage of the collector.

[0106] In this embodiment, by setting a reasonable preset fluctuation range and adjusting the preheating execution parameters in real time according to the state difference vector, freezing blockage caused by excessively low temperature or local blockage in the solar collector can be effectively avoided. In particular, by considering the freezing point of molten salt, the pipeline design of the solar collector, and the performance of the heating components, it can ensure that the temperature inside the solar collector is always within a safe range, avoiding problems such as freezing blockage, abnormal pressure, and valve jamming caused by excessively low temperature or poor flow, thereby greatly improving the safety of the system. This method makes the heating process of the solar collector more uniform and efficient by dynamically adjusting the heating intensity. When the state difference is large, the adjustment factor will increase to enhance the heating intensity. The temperature is controlled to ensure a rapid rise and maintenance within a suitable range. This not only helps avoid the risk of localized low temperatures but also improves the heat conversion efficiency of the solar collector, shortens heating time, and thus enhances the overall system efficiency. By combining the physical characteristics of the solar collector, historical operating data, and experimental results, the fluctuation range setting can more accurately adapt to the needs of different solar collectors and operating conditions. This reduces misjudgments or response lags caused by fixed temperature thresholds or uniform control strategies in traditional control methods, effectively avoiding the risk of insufficient or excessive heating due to system errors. Considering the maximum heating power and temperature control accuracy of the heating components, and incorporating safety redundancy design, the system can... It maintains high safety even under extreme conditions; in the event of abnormal fluctuations, the system can respond promptly to ensure that the solar collector will not rupture or be damaged due to overheating or excessive pressure during operation, effectively extending equipment life and reducing failure rate; this step monitors the collector's state differences in real time and dynamically adjusts it according to the preset fluctuation range, giving the control system strong intelligence and adaptability; it can not only respond to changes in the collector's state in real time, but also continuously optimize based on historical data and experimental verification results, improving the collector's adaptability and ensuring stable operation under different working conditions; and it avoids problems such as local freezing and pipe blockage. This reduces equipment failure frequency and maintenance costs. Simultaneously, more precise heating control improves heat collection efficiency and reduces energy consumption, thereby optimizing the overall system's economic benefits. It helps reduce collector maintenance and operating costs, improving the overall system's economy. By combining multiple factors and dynamically adjusting the preheating strategy, this step effectively improves collector safety, thermal efficiency, intelligence, and system stability. It also enhances redundancy design, ensuring stable and efficient system operation under various conditions. The beneficial effects of this step are not only reflected in improved system safety and stability but also in enhanced system economic benefits and reduced equipment failure rates and maintenance costs.

[0107] In some embodiments of the present invention, for step S4, the initial preheating execution parameters are corrected based on the preheating adjustment factor to obtain real-time preheating execution parameters, and the corresponding heating components are used to control the solar collector to heat it in real time.

[0108] Define the initial preheating parameters, which include heating power, heating voltage, target temperature, and heating duration.

[0109] First, perform boundary verification on the initial preheating parameters to ensure that they are within the safe operating range of the solar collector heating system, and avoid equipment damage due to parameters exceeding the standard.

[0110] For heating power and heating voltage, the initial values ​​are directly multiplied by the preheating adjustment factor to obtain the real-time heating power and voltage, which are then used to adjust the current passing through the stainless steel metal tubes of the collector, thereby changing the heating intensity. For the target temperature, during correction, it must be ensured that it is never lower than the freezing point of the molten salt to prevent the molten salt from solidifying in the pipes. At the same time, fine-tuning is made in conjunction with the heat loss of the collector. For heating duration, it is adjusted accordingly based on the magnitude of the adjustment factor. If the abnormal situation is more serious and the adjustment factor is larger, the heating duration can be appropriately extended to ensure sufficient time to resolve potential freezing and blockage risks. If overheating occurs and the adjustment factor is smaller, the duration should be shortened to avoid energy waste.

[0111] The corrected real-time preheating execution parameters are controlled by the control cabinet, which controls the corresponding heating components to heat the solar collector in real time. At the same time, the status parameters of the solar collector's input and output are monitored to ensure that the heating effect meets expectations and to ensure the safe and stable operation of the solar collector.

[0112] In this embodiment, boundary checks are performed on the initial preheating parameters to ensure that parameters such as heating power, heating voltage, target temperature, and heating duration remain within the safe operating range of the solar collector, preventing equipment damage or operational instability due to parameter exceeding limits. By adjusting the corrected heating power and heating voltage in real time, the heating intensity is dynamically adjusted to adapt to the actual needs of different operating states of the solar collector, ensuring the system is always in optimal working condition and avoiding energy waste due to insufficient or excessive heating. Correction of the target temperature ensures that the temperature never falls below the freezing point of the molten salt, preventing the molten salt from solidifying in the pipeline and thus avoiding pipeline blockage or freezing, reducing the potential risk of freezing. Dynamic adjustment of the heating duration through adjustment factors allows for timely extension or shortening of the heating time according to the actual operating conditions of the solar collector. In case of abnormalities, the heating time will be appropriately extended to ensure that the molten salt is completely thawed and flows smoothly; conversely, if there are no abnormalities, the heating time can be appropriately shortened to avoid energy waste. By monitoring and adjusting the status parameters of the collector's input and output ends in real time, the control system can effectively provide feedback and adjustment to ensure that the heating process meets expectations, improve the heating effect and safety stability of the collector, and extend the equipment life. By precisely adjusting each parameter, problems such as overheating or undercooling and uneven heating are avoided, effectively reducing the risk of failure or damage caused by equipment overload, freezing, blockage, etc. This step can improve the operating efficiency and stability of the collector while ensuring equipment safety by adjusting the preheating execution parameters in real time, preventing freezing and blockage, optimizing energy consumption, and ensuring the long-term reliable operation of the collector.

[0113] The present invention also provides a preheating control device for a molten salt trough solar collector, specifically comprising the following modules:

[0114] Support mechanism, used to provide insulating support for the metal tubes of the solar collector;

[0115] The initial preheating execution module is used to determine the initial preheating execution parameters of each collector based on the molten salt injection characteristics before the solar collector system is started, and to control the corresponding heating components to perform initial heating on the collector.

[0116] The state difference monitoring module is used to collect and calculate the state difference vector between the input and output ends of each collector in real time during the molten salt injection process. The state difference vector includes at least temperature difference, pressure difference and flow rate difference.

[0117] The preheating adjustment calculation module is used to input the state difference vector into the preheating adjustment model and output the preheating adjustment factor when the difference of any state parameter exceeds its corresponding preset fluctuation range.

[0118] The real-time preheating execution module is used to correct the initial preheating execution parameters according to the preheating adjustment factor, generate real-time preheating execution parameters, and control the corresponding heating components to heat the collector in real time.

[0119] In this embodiment, the device, through an initial preheating execution module, customizes initial preheating execution parameters for each collector based on the molten salt injection characteristics and structural differences of each collector. This ensures that the collector is in the most suitable heating state for its own conditions from the initial preheating stage, avoiding underheating or overheating of some collectors due to the use of fixed parameters, thereby improving preheating efficiency. The real-time preheating execution module can correct the initial preheating execution parameters according to the preheating adjustment factor and control the heating components to heat the collector in real time. During the molten salt injection process, as the internal state of the collector changes, the device can adjust the heating power and method in a timely manner to always keep the collector in the optimal heating state. The heater is kept in optimal preheating condition to avoid uneven or insufficient preheating caused by excessive or insufficient heating power in the later stages of preheating, thereby further improving preheating efficiency. The state difference monitoring module collects and calculates the state difference vector between the input and output ends of the collector in real time during the molten salt injection process. The state difference vector includes temperature difference, pressure difference, and flow difference. When abnormal situations such as a sudden drop in flow rate due to local blockage occur, this module can quickly detect changes in the flow difference. The preheating adjustment calculation module will promptly input the state difference vector into the preheating adjustment model and output the preheating adjustment factor, which will then be used by the real-time preheating execution module to adjust the heating strategy.

[0120] Furthermore, the support mechanism is a type of bracket structure used to fix and support the metal tubes of the solar collector, including but not limited to drive brackets and clamp brackets, and also covers other support forms suitable for molten salt trough solar collectors, such as truss brackets, cantilever brackets, and floor-mounted brackets; its core function is to bear the weight of the metal tubes of the solar collector and maintain their spatial position, ensuring the relative fixation of the metal tubes of the solar collector to the external structure.

[0121] To block the conductive path between the collector metal tube and the support structure, and to ensure that the DC heating circuit heats up only through the resistance of the collector tube 5 itself, thus avoiding the risk of leakage and short circuit, an insulation structure is installed between all support structures and the collector metal tube.

[0122] Insulating structures are installed at the contact or connection points between the collector's metal tubes and the support mechanism, such as the metal contact surface, the location where connecting bolts pass through, and the fixing points between the bracket and the collector. The structural forms of the insulating components include, but are not limited to, pads, bolt sleeves, gaskets, sleeves, inserts, coatings, and assemblies, and their materials are high-temperature resistant insulating materials.

[0123] Specifically, such as Figure 4As shown, taking the drive bracket as an example, the drive bracket consists of a bracket top seat 11, a bracket base 12, a transition metal tube 13, and connecting bolts passing through bolt holes 14; the drive bracket is provided with a first insulation component, which achieves insulation between the metal surface of the drive bracket and the heat collection tube 5 through an insulation pad 15, an insulation bolt sleeve 17, and an insulation gasket 16.

[0124] The insulating pad 15 can be made of alumina, zirconium oxide, or silicon nitride ceramics, with an area consistent with the lower surface of the bracket top seat 11 and the upper surface of the bracket base 12. It is installed between the metal contact surfaces of the two to block direct conductivity. The insulating bolt sleeve 17 is a ceramic tubular structure with an inner diameter adapted to the diameter of the connecting bolt. It is sleeved on the outside of the bolt and its length covers the exposed section of the bolt to prevent the bolt from contacting the metal hole wall of the bracket. The insulating gasket 16 is a ceramic disc with an outer diameter slightly larger than the nut diameter. It is placed between the nut and the outer surface of the bracket top seat 11 to enhance the insulation effect at the nut. The connecting bolt passes through the bracket top seat 11, the insulating bolt sleeve 17, the insulating pad 15, the bracket base 12, the insulating gasket 16, and the nut in sequence to form a full-path insulation blockage, ensuring that there is no metal conduction between the drive bracket and the heat collection tube 5.

[0125] More specifically, for the bolt holes 14 of the bracket base 12, an annular mounting groove is opened on the inner wall of the bolt holes 14, the groove depth is ≥ 1 / 2 of the depth of the bolt holes 14, and the groove width matches the thickness of the insulation material; the insulation material is a high-temperature resistant insulation material such as PEEK; the insulation material is processed into an annular insert and tightly embedded in the mounting groove, so that the bolt only contacts the insulation material when passing through, completely blocking the conductive path between the screw and the bracket base 12; the interlocking structure prevents the insulation components from shifting when the bolts are tightened, improving the insulation reliability for long-term use.

[0126] Furthermore, such as Figure 5 As shown, taking the clamp bracket as an example, the clamp bracket consists of a frame bracket 1, a spring plate 2, a clamp support pin 6, a clamp fastener 4, and a bottom support 3, which are used to fix the heat collection tube 5; the second insulation component achieves insulation between the clamp and the heat collection tube 5 through the form of insulating sleeve 8, coating, heat insulation component 7, and insulating sleeve group 9, etc.

[0127] Specifically, the insulating sleeve 8 has a T-type ceramic structure, as shown in the following details: Figure 6 As shown, the material is aluminum oxide, with a temperature resistance of ≥300℃. The transverse section is sleeved on the outside of the clamp support pin 6. The inner diameter of the sleeve is matched with the diameter of the pin, and the wall thickness is ≥3mm. It is fixed by the clamp fastener 4 to prevent the pin from contacting the metal with the frame bracket 1.

[0128] The heat insulation component 7 is made of high-temperature resistant aerogel, with an inner diameter consistent with the outer diameter of the heat collection tube 5 and a width equal to the distance between two adjacent heat collection tubes 5; it is fixed to the frame bracket 1 by the heat collection tube 5 clamp fastener 4, thereby achieving heat insulation and insulation between the clamp fastener 4 and the heat collection tube 5.

[0129] The insulating sleeve 9 is composed of multiple layers of high-temperature resistant insulating materials, including mica and bakelite. The overall structure is a sleeve-like structure adapted to the installation size of the spring plate 2, and has through holes corresponding to the installation holes of the spring plate 2 for connecting components to pass through. It is installed at the spring plate 2 of the clamp bracket. The inner side of the insulating sleeve 9 is tightly attached to the surface of the spring plate 2, and the outer side forms an insulating gap with other metal parts of the clamp bracket. By setting the insulating sleeve 9 at the installation position of the spring plate 2, the conductive path between the spring plate 2 and the metal structure of the clamp bracket is blocked, further strengthening the insulation between the clamp bracket and the metal tube of the collector. In conjunction with the heat insulation component 7 and the insulating sleeve 8, reliable insulation between the clamp bracket and the metal tube of the collector is achieved.

[0130] In this embodiment, by setting insulating components at the bolt fastening parts of the drive bracket and the clamping parts of the clamp bracket, the conductive path between the collector metal tube and the support mechanism can be effectively blocked, ensuring that the DC heating circuit heats up only through the resistance of the collector tube itself, avoiding the risk of leakage and short circuit caused by metal contact, while ensuring the accurate transmission of heating current, improving preheating efficiency and system safety.

[0131] Regarding the above embodiments, it should be noted that the materials of the first and second insulating components are not limited to the specifically listed insulating materials such as mica, bakelite, ceramics (alumina, zirconium oxide, silicon nitride), PPS (polyphenylene sulfide), PEEK (polyether ether ketone), and polyimide. They also include all similar or equivalent insulating materials that can meet the requirements of high temperature resistance and high insulation performance. The core is to ensure reliable insulation between the collector metal tube and the support structure under high temperature conditions, and to block the conductive path to ensure the safety and effectiveness of the DC heating circuit.

[0132] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preheating control method for a molten salt trough solar collector, characterized in that, include: Before the solar collector system is started, the initial preheating execution parameters of each solar collector are determined based on the molten salt injection characteristics, and the corresponding heating components are used to control the initial heating of the solar collector. Determining the initial preheating execution parameters for each solar collector includes: acquiring molten salt injection characteristics and multiple sets of collector state characteristics; the multiple sets of collector state characteristics correspond to multiple collectors in the solar collector system, wherein each collector is configured with a set of heating components; based on the molten salt injection characteristics, and in conjunction with the collector state characteristics of each collector, a freezing blockage risk assessment is performed on each collector to obtain a freezing blockage risk index corresponding to each collector; for each collector, according to the corresponding freezing blockage risk index and the performance parameters of its heating components, a mapping is performed in a preset preheating strategy library to obtain the initial preheating parameters corresponding to that heating component. The preheating execution parameters are as follows: The steps of the freezing and blockage risk assessment are as follows: Construct a three-level hierarchical assessment structure including a target layer, a criterion layer, and an indicator layer, wherein the target layer is for freezing and blockage risk assessment, the criterion layer includes molten salt injection characteristics and collector status characteristics, and the indicator layer consists of specific characteristic parameters corresponding to the criterion layer; Compare factors in each level pairwise to determine the relative importance weight of each factor; Divide the preset evaluation level according to the actual value of each characteristic parameter, and count the frequency of each characteristic parameter belonging to each evaluation level to construct a fuzzy evaluation matrix; Combine the weights with the fuzzy evaluation matrix to obtain the freezing and blockage risk index of the corresponding collector; During the injection process, the state difference vector corresponding to each collector is monitored in real time; the state difference vector represents the difference of various state parameters between the input and output ends of the collector. In response to any state parameter difference exceeding the corresponding preset fluctuation range, the state difference vector is input into the preset preheating adjustment model to obtain the preheating adjustment factor. The initial preheating execution parameters are corrected based on the preheating adjustment factor to obtain real-time preheating execution parameters, and the corresponding heating components are used to control the real-time heating of the solar collector.

2. The preheating control method for a molten salt trough solar collector according to claim 1, characterized in that, The molten salt injection characteristics include molten salt injection temperature, molten salt injection pressure, and molten salt freezing point.

3. The preheating control method for a molten salt trough solar collector according to claim 1, characterized in that, The characteristics of the solar collector include pipe length, pipe inner diameter, and initial pipe temperature.

4. The preheating control method for a molten salt trough solar collector according to claim 1, characterized in that, The performance parameters of the heating component include at least the maximum heating power, heating efficiency, temperature control accuracy, and response time.

5. The preheating control method for a molten salt trough solar collector according to claim 1, characterized in that, The preset preheating strategy library includes strategies such as phased preheating strategy, dynamic adjustment preheating strategy, and safety redundancy preheating strategy.

6. A preheating control device for a molten salt trough solar collector, wherein the device is applied to the preheating control method for a molten salt trough solar collector as described in claim 1, characterized in that, include: Support mechanism, used to provide insulating support for the metal tubes of the solar collector; The initial preheating execution module is used to determine the initial preheating execution parameters of each collector based on the molten salt injection characteristics before the solar collector system is started, and to control the corresponding heating components to perform initial heating on the collector. The state difference monitoring module is used to collect and calculate the state difference vector between the input and output ends of each collector in real time during the molten salt injection process. The state difference vector includes at least temperature difference, pressure difference and flow rate difference. The preheating adjustment calculation module is used to input the state difference vector into the preheating adjustment model and output the preheating adjustment factor when the difference of any state parameter exceeds its corresponding preset fluctuation range. The real-time preheating execution module is used to correct the initial preheating execution parameters according to the preheating adjustment factor, generate real-time preheating execution parameters, and control the corresponding heating components to heat the collector in real time.

7. The preheating control device for a molten salt trough solar collector according to claim 6, characterized in that, The support mechanism includes at least a drive bracket and a clamp bracket; The drive bracket is provided with a first insulating component to achieve insulation between the drive bracket and the metal tube of the solar collector. The clamp bracket is provided with a second insulation component to achieve insulation between the clamp bracket and the metal tube of the solar collector. Both the first insulating component and the second insulating component are made of insulating material.

8. The preheating control device for a molten salt trough solar collector according to claim 7, characterized in that, The first insulating component includes at least an insulating pad, an insulating bolt sleeve, and an insulating gasket; The insulating pad is installed between the top seat of the drive bracket and the base of the bracket; The insulating bolt sleeve is adapted to the screw of the drive bracket and is sleeved on the outside of the screw; The insulating gasket is placed on the nut side of the drive bracket.

9. The preheating control device for a molten salt trough solar collector according to claim 7, characterized in that, The second insulation assembly includes at least a thermal insulation component, an insulating sleeve, and an insulating sleeve group; The inner diameter of the heat insulation component is the same as the outer diameter of the collector metal tube, the width is the distance between two adjacent collector metal tubes, and it is fixed to the collector metal tube by a clamp structure. The insulating sleeve is fitted onto the outside of the pin of the clamp bracket; The insulating sleeve is installed at the spring plate of the clamp bracket.

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