Molten salt heat release temperature adjusting system and temperature adjusting method

Abstract

The invention relates to the technical field of thermal power generation, in particular to a fused salt heat release temperature adjusting system and a temperature adjusting method, and aims to solve the problem of damage caused by too fast temperature rise of equipment and pipelines when high-temperature fused salt is injected into a heat release system. The system comprises a hot salt tank, a cold salt tank, a salt dredging tank, a superheater, an evaporator, a preheater, a hot salt pipe, a cold salt pipe and a salt conveying pipe, wherein the hot salt pipe, the cold salt pipe and the salt conveying pipe are matched, and a hot salt pump, a cold salt pump, a hot salt valve, a cold salt valve, a salt conveying valve, the cold salt pipe and the hot salt pipe are all connected into a main pipe of an inlet of the superheater. According to the temperature regulation method, temperature rise is controlled through the steps of mixing proportion calculation, cold salt injection, hot salt injection, PID + feedforward compensation temperature regulation and cold salt circulation shutdown, and an exception handling mechanism is set. The method can stably control the temperature rise rate of the equipment and the pipeline to be less than or equal to 6 DEG C / min, protects the safety of the equipment, improves the flexibility of a thermal power generating unit, meets the peak regulation and peak demands of a new energy power system, and improves the competitiveness of a power plant.

Description

Technical Field

[0001] This invention relates to the field of thermal power generation technology, and in particular to a molten salt exothermic temperature control system and method. Background Technology

[0002] To improve the flexibility of thermal power units, alleviate the pressure of deep peak shaving in power plants, adapt to the needs of the new power system dominated by new energy sources, and enhance the competitiveness of power plants in the future electricity market, a molten salt-extraction steam storage system is adopted for energy storage and heat release. This involves extracting a portion of steam from the main steam system and the reheat steam system to heat molten salt and store heat. During peak electricity demand periods, the heat stored in the molten salt storage system is returned to the thermal system, increasing the power plant's output and thus playing a peak-shaving role. During heat release, the hot salt pump is started, and the electric valve at the superheater inlet is opened to inject hot salt into the heat release system. However, during the high-temperature molten salt injection process, the equipment and pipelines are prone to excessively rapid temperature rise, potentially damaging the equipment. Summary of the Invention

[0003] To address the problem of excessively rapid temperature rise in equipment and pipelines during high-temperature molten salt injection, which can damage the equipment, this invention aims to provide a molten salt exothermic temperature control system and method to control the temperature rise of equipment and pipelines in the exothermic system to <6℃ / min.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] Structure of molten salt exothermic temperature control system:

[0006] The hot salt tank outlet is connected to a hot salt pipe to store high-temperature molten salt, providing a heat source for exothermic reactions. One end of the hot salt pipe is connected to the hot salt tank, and the other end is connected to a main pipe. A hot salt pump and a hot salt valve are installed on the pipe. The hot salt pump provides power for hot salt delivery, and the hot salt valve controls the hot salt flow rate. The salt drain tank inlet is connected to a salt delivery pipe, and the outlet is connected to a cold salt pipe. It is used to temporarily store cold salt awaiting use, stabilizing the cold salt supply pressure and temperature. One end of the salt delivery pipe is connected to the preheater outlet, and the other end is connected to the salt drain tank. A salt delivery valve is installed on the pipe to deliver low-temperature molten salt from the preheater outlet to the salt drain tank. The salt delivery valve controls the amount of cold salt delivered. The cold salt pipe is connected to the salt drain tank, and the other end is connected to a main pipe. A cold salt pump and a cold salt valve are installed on the pipe. The cold salt pump provides power for cold salt delivery, and the cold salt valve is the core actuator for temperature control, adjusting the amount of cold salt by controlling its opening degree. One end of the main pipe connects to the hot salt pipe and the cold salt pipe, and the other end connects to the superheater inlet, which can realize the mixing of hot salt and cold salt and provide the superheater with a temperature-stable mixed salt.

[0007] The superheater, evaporator, and preheater are connected in series. The superheater outlet is connected to the evaporator inlet, the evaporator outlet is connected to the preheater inlet, and the preheater outlet is connected to the cold salt tank. The three together complete the heat release cycle of molten salt. The superheater releases heat, and the evaporator and preheater further exchange heat. After heat exchange, the low-temperature molten salt enters the cold salt tank for storage. The cold salt tank inlet is connected to the preheater outlet and is used to store the low-temperature molten salt after heat exchange, serving as a supplementary source of cold salt.

[0008] Molten salt exothermic temperature control method:

[0009] 1. Calculate the mixing ratio: Based on the current temperatures of hot and cold salt, preliminarily determine the range of mixing ratios between cold and hot salt through calculation.

[0010] 2. Cold salt injection: Start the cold salt pump and run it until the parameters are stable. Cold salt enters the cold salt pipe (3) from the salt tank (10). If the outlet pressure fluctuation is ≤ ±0.05MPa, the motor current is stable at 80%-100% of the rated value, the vibration value is ≤4.5mm / s, and the running time is ≥30s, the cold salt pump is judged to be running stably. Linearly open the cold salt valve, set the opening time to 10s, and set the initial opening degree to 20%. Cold salt enters the main pipe (1) from the cold salt pipe (3). Monitor the pressure of the temperature regulating pipeline and the flow rate of cold salt. If there are no abnormalities for a period of time, hot salt is injected.

[0011] 3. Hot salt injection: Preheat the hot salt pump and then start the hot salt pump; the hot salt pump needs to be preheated to a pump body temperature ≥150℃ and the start interval between the hot salt pump and the cold salt pump should be ≥2min; run until the parameters are stable, hot salt enters the hot salt pipe (2) from the hot salt tank (11), and the hot salt valve is opened linearly, and hot salt enters the main pipe (1) from the hot salt pipe (2); the outlet pressure is stable at 1.2-1.5MPa, the motor current is ≤ rated value, the bearing temperature is ≤85℃, and the running time is ≥30s, which is considered stable operation; the opening time of the hot salt valve is set to 15s, and the initial opening degree is set to 20% to avoid hot salt impacting the pipeline.

[0012] 4. Temperature control: Hot and cold salts are mixed in the header pipe, and the temperature of the mixed salt is collected. The instantaneous temperature rise rate is calculated every 10 seconds. =2×(T 当前 -T 30s前 ), where T 当前 T represents the current temperature. 30s前 The temperature was set 30 seconds ago, and the upper limit of the control range is 6℃ / min. The control objective is to stabilize the temperature rise rate within the range of 4-6℃ / min, minimizing deviation and adjustment energy consumption. The objective function is: , Where ω1=0.8, ω2=0.2, This represents the change in the opening degree of the cold salt valve. For the target temperature rise rate, take And it satisfies the following constraints: | ≤10% / time.

[0013] The opening degree of the cold salt valve is adjusted using a PID algorithm, and the PID parameters are dynamically adjusted based on the temperature rise rate range.

[0014] If detected twice consecutively >6℃ / min, triggering over-limit adjustment: The adjustment formula is: ,in, Let e(k) be the change in the opening degree of the cold salt valve (5) at time k, and e(k) = V 目标 -V 实(k) With Kp1=1.2, Ki1=0.06, and Kd1=0.3, the opening of the cold salt valve is increased in a step-by-step adjustment mode, with a 2% opening increment every 5 seconds, and a single adjustment range ≤10%, until... ≤6℃ / min; if after the first adjustment, continuous monitoring for 90 seconds still results in... >6℃ / min, the second adjustment increases Kp1 to 1.5 to accelerate the adjustment response speed;

[0015] If 4℃ / min≤ ≤6℃ / min, the adjustment formula is: Kp2=0.6, Ki2=0.03, Kd2=0.1, to maintain a stable opening of the cold salt valve;

[0016] If detected twice consecutively <4℃ / min, triggering low-temperature adjustment: The adjustment formula is: With Kp3=1.0, Ki3=0.05, and Kd3=0.2, the opening of the cold salt valve is reduced in a smooth adjustment mode, decreasing by 1-2% every 5 seconds, with a single adjustment increment ≤10%, until... ≥4℃ / min; if still after adjustment If the flow rate is less than 4℃ / min, prioritize adjusting the hot salt pump outlet pressure to 1.2-1.5MPa before adjusting the cold salt injection rate.

[0017] Dead zone range: when At this time, do not perform adjustments to avoid frequent operation that could damage the valve.

[0018] Simultaneously, the real-time flow rates of hot and cold salt are collected. When the flow rate fluctuations are too large, a feedforward compensation algorithm is activated to calculate the cold salt adjustment amount in advance and perform flow rate compensation. , in Let k be the opening degree of the cold salt valve. The change in the opening of the cold salt valve (5) based on PID control at time k. , This represents the change in thermosalinity flow rate. =0.05% / (t·h -1 This helps to offset the effects of temperature and salinity fluctuations in advance.

[0019] 5. Shutdown: Gradually close the hot salt valve to reduce the injection of hot salt, then turn off the hot salt pump and keep the cold salt pump running for 5 to 10 minutes to reduce the temperature of the equipment and pipelines by circulating cold salt. After the temperature drops to a safe range, close the cold salt valve and stop the cold salt pump.

[0020] Preferably, the system also includes abnormal handling steps: If the temperature rise rate suddenly exceeds 6℃ / min and cannot be reduced by increasing the cold salt injection rate, immediately stop the hot salt pump, close the hot salt valve, increase the cold salt injection rate to lower the temperature, check for any abnormalities in the hot salt pump and hot salt delivery pipeline, and restart the system after troubleshooting; If the temperature rise rate is much lower than 6℃ / min and there is still no significant change after reducing the cold salt injection rate, it may be that the cold salt temperature is too low or the cold salt injection rate is not properly controlled. Check the temperature of the cold salt in the salt tank. If the temperature is too low, the cold salt delivery rate in the salt delivery pipeline can be appropriately reduced. At the same time, check for any problems such as jamming in the cold salt valve to ensure that it can adjust its opening normally; If molten salt leakage occurs, the system should be stopped immediately, the relevant valves should be closed, safety protection measures should be taken, and the system should be restarted after the leak is repaired.

[0021] Working principle: The high-temperature molten salt in the hot salt tank is transported to the main pipe through the hot salt pipe; the low-temperature molten salt at the preheater outlet is temporarily stored in the salt evaporation tank through the salt conveying pipe, and then transported to the main pipe through the cold salt pipe; the hot salt and cold salt are fully mixed in the main pipe to form a temperature-stable mixed salt, which then enters the superheater to release heat, and then flows through the evaporator and preheater in sequence to complete heat exchange. Finally, the low-temperature molten salt enters the cold salt tank for storage, realizing a closed-loop circulation of molten salt.

[0022] The system collects real-time data on the mixed salt temperature, hot salt flow rate, cold salt flow rate, and pump and valve operating parameters. It calculates the temperature rise rate every 10 seconds to determine if it is within the target range. If the temperature rise deviates from the target, it uses a PID algorithm to adjust the opening of the cold salt valve in segments. When the temperature rise exceeds the target, it increases the amount of cold salt; when it is too low, it decreases the amount of cold salt, minimizing the temperature rise deviation and adjustment energy consumption. If the hot salt flow rate fluctuates, it uses a feedforward compensation algorithm to calculate the cold salt adjustment amount in advance to offset the impact of hot salt fluctuations on the mixed salt temperature.

[0023] When shutting down, do not cut off all molten salt supply directly. First, turn off the hot salt pump and hot salt valve, and keep the cold salt pump running for 5-10 minutes. Utilize the circulation of cold salt in the equipment and pipelines to slowly reduce the temperature of the equipment and pipelines.

[0024] When the system experiences abnormalities such as excessive temperature rise, cold salt failure, or molten salt leakage, take immediate corresponding measures: If the temperature rise exceeds the limit, prioritize cutting off the hot salt supply, then increase the amount of cold salt to force cooling and prevent equipment damage from overheating; if the cold salt fails, check the cold salt temperature and valve status, and quickly restore the cold salt regulation capability; if the molten salt leaks, immediately cut off all molten salt sources, take safety precautions, prevent the accident from escalating, and ensure the safety of personnel and equipment.

[0025] The present invention has the following beneficial effects:

[0026] 1. Protect equipment and extend its service life.

[0027] Thermal shock during direct injection of high-temperature molten salt is the core cause of equipment damage. This system uses a "cold salt pre-charging + cold and hot salt mixing temperature regulation" mechanism, combined with precise control of PID + feedforward compensation, to stably control the temperature rise rate of equipment and pipelines at 4-6℃ / min, avoiding local overheating or sudden temperature changes, and reducing the frequency and cost of equipment replacement and maintenance.

[0028] 2. Enhance unit flexibility to adapt to peak-shaving demands from renewable energy sources.

[0029] In a new power system dominated by new energy sources, the volatility of wind and solar power necessitates that thermal power units possess rapid peak-shaving and peak-loading capabilities. This system, through flexible regulation of molten salt heat release, can significantly shorten the load response time of thermal power units; during grid off-peak hours, molten salt heat storage is utilized, and during grid peak hours, precisely temperature-controlled molten salt heat release supplements the heat supply, thereby increasing unit output.

[0030] 3. High adjustment precision

[0031] This invention employs segmented PID control, dynamically switching PID parameters according to the temperature rise rate range to adapt to temperature control requirements under different conditions, making temperature control more precise; it also monitors hot salt flow fluctuations in real time, calculates cold salt adjustment amounts in advance, and counteracts the impact of flow disturbances on temperature, avoiding sudden temperature increases.

[0032] 4. Operational safety

[0033] The system has designed solutions for the core risks of molten salt exothermic reactions (excessive temperature rise, cold salt failure, and molten salt leakage) to prevent casualties or chain accidents and meet the high safety standards of thermal power generation. Attached Figure Description

[0034] Figure 1 This is a diagram of the original exothermic system of the molten salt exothermic temperature control system and method proposed in this invention.

[0035] Figure 2 This is a diagram of the exothermic system after the addition of the temperature control system to the molten salt exothermic temperature control system and temperature control method proposed in this invention.

[0036] Figure 3 This is a flowchart of the temperature control method for the molten salt exothermic temperature control system and method proposed in this invention.

[0037] Explanation of reference numerals in the attached diagram: 1. Main pipe; 2. Hot brine pipe; 3. Cold brine pipe; 4. Cold brine pump; 5. Cold brine valve; 6. Hot brine pump; 7. Hot brine valve; 8. Brine delivery pipe; 9. Brine delivery valve; 10. Salt drain tank; 11. Hot brine tank; 12. Superheater; 13. Evaporator; 14. Preheater; 15. Cold brine tank. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] The following example, using a molten salt exothermic temperature control system for a 300MW thermal power unit, illustrates the specific implementation process of this invention in detail:

[0040] This 300MW thermal power unit is equipped with a molten salt-extraction steam storage system. Hot salt tank 11 stores a mixed molten salt of sodium nitrate and potassium nitrate at 380℃, while cold salt tank 15 stores the same type of molten salt at 220℃. The goal of this system is to stabilize the temperature rise rate of the mixed salt at the superheater inlet 12 at 4-6℃ / min. Regarding equipment parameters, hot salt pump 6 has a rated current of 120A, a rated outlet pressure of 1.5MPa, and a bearing temperature limit of 85℃; cold salt pump 4 has a rated current of 100A, a rated outlet pressure of 2.0MPa, and a vibration limit of 4.5mm / s; the linear adjustment response time of cold salt valve 5 and hot salt valve 7 is ≤1s.

[0041] S1: Calculate the mixing ratio; based on the heat balance formula. ,in , The specific heat capacity of molten salt, For quality, Given the temperature change, the temperature of the thermosalinous zone is known. Cold salt temperature Initial temperature of the target mixed salt Total mass flow rate of mixed salt Substituting into the formula, we can obtain and Solving for , The initial mixing ratio of cold salt to hot salt was determined to be 1:2.

[0042] S2: Cold Salt Injection: Start cold salt pump 4 and monitor operating parameters in real time. The outlet pressure is stable at 2.0 MPa with a fluctuation of ±0.03 MPa, the motor current is stable at 90 A, and the pump body vibration is 3.8 mm / s. After running continuously for 35 seconds, cold salt pump 4 is determined to be operating stably. Then, open cold salt valve 5 and use linear adjustment mode to slowly increase the opening from 20% to 30% within 10 seconds. During this period, monitor the cold salt flow rate and ensure there are no fluctuations, confirming that the cold salt injection is normal.

[0043] S3: Hot Salt Injection: Preheat the hot salt pump 6 to 155℃. After preheating, set the start interval between the hot salt pump 6 and the cold salt pump 4 to 2.5 minutes. After starting the hot salt pump 6, monitor the operating parameters in real time. The outlet pressure stabilizes at 1.3MPa, the motor current stabilizes at 110A, and the bearing temperature stabilizes at 80℃. After running continuously for 32 seconds, the hot salt pump 6 is deemed to be operating stably. Then, open the hot salt valve 7 and use the linear adjustment mode to slowly increase the opening from 20% to 60% within 15 seconds. The hot salt and cold salt begin to mix in the main pipe 1.

[0044] S4: Temperature Control: Collect the temperature of the mixed salt every 10 seconds. The first collection is... The data was collected after 30 seconds. Calculate according to the formula Within the target range of 4-6℃ / min, using , , The PID parameters were kept constant at 30% opening of the cold salt valve 5.

[0045] After running for 10 minutes, the outlet pressure of hot salt pump 6 fluctuated slightly, causing the hot salt flow rate to increase from 50 t / h to 55 t / h. According to the formula... Immediately adjust the opening of the cold salt valve 5 from 30% to 30.25% to preemptively offset the impact of the increased hot salt flow on the temperature rise, ultimately... It remains at 5.1℃ / min.

[0046] After a period of time, the temperature rise rate of the mixed salt was monitored twice consecutively, both times reaching 6.2℃ / min, triggering an over-limit adjustment. Calculation Substitute into the formula Increase the opening of the cold salt valve by 2% every 5 seconds. After the first adjustment, the opening is 32%. The temperature dropped to 5.8℃ / min, then adjustment was stopped, and the temperature returned to stability.

[0047] S5: Shutdown: Gradually close the hot salt valve 7, reducing the opening from 60% to 0% within 10 seconds, then shut down the hot salt pump 6; keep the cold salt pump 4 running for 8 minutes, using cold salt circulation to reduce the temperature of the superheater 12, evaporator 13 and pipes from 350℃ to 240℃; finally close the cold salt valve 5, stop the cold salt pump 4, and complete the shutdown.

[0048] Example of abnormal handling: During operation, due to partial blockage of hot salt pipe 2, the hot salt flow rate suddenly decreased, and the mixed salt temperature rise rate dropped to 3.8℃ / min, triggering a low-temperature regulation. Calculation Substitute into the formula Every 5 seconds, the opening of the cold salt valve was reduced by 1%. After three adjustments, the opening was 27%. The pressure remained at 3.9℃ / min. The outlet pressure of hot salt pump 6 was checked first; it was found to have dropped to 1.0MPa, indicating a blockage in the hot salt pipe. Hot salt valve 7 was closed, hot salt pump 6 was stopped, the hot salt pipe 2 was cleared, and the hot salt pump was restarted. The outlet pressure was adjusted to 1.3MPa, and the opening of cold salt valve 5 was restored to 30%. The temperature rises to 5℃ / min, and the system returns to normal.

[0049] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A molten salt exothermic temperature control system, comprising a hot salt tank (11), a superheater (12), a header pipe (1) at the inlet of the superheater (12), an evaporator (13) connected to the outlet of the superheater (12), a preheater (14) connected to the outlet of the evaporator (13), and a cold salt tank (15) connected to the outlet of the preheater (14), characterized in that: The hot salt tank (11) has a hot salt pipe (2) at its outlet. A hot salt pump (6) and a hot salt valve (7) are installed on the hot salt pipe (2). The other end of the hot salt pipe (2) is connected to the main pipe (1). The preheater (14) also has a salt conveying pipe (8) at its outlet. A salt conveying valve (9) is installed on the salt conveying pipe (8). The other end of the salt conveying pipe (8) is connected to the inlet of the salt sludge tank (10). The salt sludge tank (10) has a cold salt pipe (3) at its outlet. A cold salt pump (4) and a cold salt valve (5) are installed on the cold salt pipe (3). The other end of the cold salt pipe (3) is also connected to the main pipe (1).

2. The temperature control method for the molten salt exothermic temperature control system according to claim 1, used for temperature control when high-temperature molten salt is injected into the exothermic system, characterized in that: Includes the following steps: S1. Calculate the mixing ratio: Based on the current temperatures of the hot and cold salts, preliminarily determine the range of mixing ratios between the cold and hot salts through calculation; S2, Cold salt injection: Start the cold salt pump (4), run until the parameters are stable, cold salt enters the cold salt pipe (3) from the salt tank (10), linearly open the cold salt valve (5), cold salt enters the main pipe (1) from the cold salt pipe (3), monitor the pressure of the temperature control pipeline and the flow rate of cold salt, and inject hot salt if there are no abnormalities for a period of time. S3, Hot salt injection: Preheat the hot salt pump (6), then start the hot salt pump (6) and run until the parameters are stable. The hot salt enters the hot salt pipe (2) from the hot salt tank (11). The hot salt valve (7) is opened linearly, and the hot salt enters the main pipe (1) from the hot salt pipe (2). S4. Temperature regulation: Hot salt and cold salt are mixed in the main pipe (1), the temperature of the mixed salt is collected, the temperature rise rate is calculated, the opening of the cold salt valve (5) is adjusted by PID algorithm, the PID parameters are dynamically adjusted based on the temperature rise rate range, and the real-time flow of hot salt and cold salt is collected at the same time. When the flow fluctuation is too large, the feedforward compensation algorithm is started to calculate the cold salt adjustment amount in advance and perform flow compensation. S5. Shutdown: Gradually close the hot salt valve (7) to reduce the injection of hot salt, then close the hot salt pump (6) and keep the cold salt pump (4) running for 5 to 10 minutes to reduce the temperature of the equipment and pipelines by circulating cold salt. After the temperature drops to a safe range, close the cold salt valve (5) and stop the cold salt pump (4).

3. The molten salt exothermic temperature control method according to claim 2, characterized in that: It also includes abnormal handling steps: If the temperature rise rate suddenly exceeds 6℃ / min and cannot be reduced by increasing the cold salt injection amount, immediately stop the hot salt pump (6), close the hot salt valve (7), increase the cold salt injection amount to cool down, check whether there is any abnormality in the hot salt pump and hot salt delivery pipeline, and restart the system after troubleshooting; If the temperature rise rate is much lower than 6℃ / min and there is still no significant change after reducing the cold salt injection amount, it may be that the cold salt temperature is too low or the cold salt injection amount is not properly controlled. Check the temperature of the cold salt in the salt tank (10). If the temperature is too low, the cold salt delivery amount of the salt delivery pipe (8) can be appropriately reduced. At the same time, check whether there is any problem such as jamming in the cold salt valve (5) to ensure that it can adjust the opening normally; If molten salt leakage occurs, the system operation should be stopped immediately, the relevant valves should be closed, safety protection measures should be taken, and the system should be restarted after the leak is repaired.

4. The molten salt exothermic temperature control method according to claim 2, characterized in that: In S2, the outlet pressure fluctuation is ≤ ±0.05MPa, the motor current is stable at 80%-100% of the rated value, the vibration value is ≤4.5mm / s, and the running time is ≥30s, so the cold salt pump (4) is judged to be running stably; the cold salt valve (5) adopts a linear adjustment mode during the opening process, the opening time is set to 10s, and the initial opening degree is set to 20%.

5. The molten salt exothermic temperature control method according to claim 2, characterized in that: In S3, the hot salt pump (6) needs to be preheated to a pump body temperature ≥150℃, and the start-up interval between it and the cold salt pump (4) should be ≥2min; monitor the operating parameters of the hot salt pump (6): the outlet pressure is stable at 1.2-1.5MPa, the motor current is ≤ rated value, the bearing temperature is ≤85℃, and the running time is ≥30s, which is considered to be stable operation; the opening time of the hot salt valve (7) is set to 15s, and the initial opening degree is set to 20%.

6. The molten salt exothermic temperature control method according to claim 2, characterized in that: In S4, temperature data of the mixed salt is continuously collected, and the instantaneous temperature rise rate is calculated every 10 seconds. =2×(T 当前 -T 30s前 ), where T 当前 T represents the current temperature. 30s前 The temperature is set 30 seconds ago, and the upper limit of the control is 6℃ / min for real-time comparison.

7. The molten salt exothermic temperature control method according to claim 2, characterized in that: In S4, the control objective is to stabilize the temperature rise rate within the range of 4-6℃ / min, minimizing the deviation and regulation energy consumption. The objective function is: ， Where ω1=0.8, ω2=0.2, The change in the opening degree of the cold salt valve (5) For the target temperature rise rate, take And it satisfies the following constraints: | ≤10% / time.

8. The molten salt exothermic temperature control method according to claim 2, characterized in that: In S4, the PID control based on the temperature rise rate is as follows: If detected twice consecutively >6℃ / min, triggering over-limit adjustment: The adjustment formula is: ,in, Let e(k) be the change in the opening degree of the cold salt valve (5) at time k, and e(k) = V 目标 -V 实(k) Kp1=1.2, Ki1=0.06, Kd1=0.3, increase the opening of the cold salt valve (5) in a step-by-step adjustment mode, with a 2% opening increment every 5 seconds, and a single adjustment range ≤10%, until ≤6℃ / min; If 4℃ / min≤ ≤6℃ / min, the adjustment formula is: Kp2=0.6, Ki2=0.03, Kd2=0.1, maintain the opening of the cold salt valve (5) stable; If detected twice consecutively <4℃ / min, triggering low-temperature adjustment: The adjustment formula is: Kp3=1.0, Ki3=0.05, Kd3=0.2, reduce the opening of the cold salt valve (5) in smooth adjustment mode, perform 1-2% opening reduction every 5s, and the single adjustment range is ≤10%, until ≥4℃ / min; Dead zone range: when At that time, no adjustment is implemented.

9. The molten salt exothermic temperature control method according to claim 2, characterized in that: In S4, feedforward compensation for thermosalinity flow disturbance is incorporated: ， in The opening degree of the cold salt valve (5) at time k. The change in the opening of the cold salt valve (5) based on PID control at time k. , This represents the change in thermosalinity flow rate. =0.05% / (t・h -1 This helps to offset the effects of temperature and salinity fluctuations in advance.

10. The molten salt exothermic temperature control method according to claim 2, characterized in that: In S4, if the over-limit adjustment fails to be implemented and monitoring continues for 90 seconds after the first adjustment... For speeds >6℃ / min, the second adjustment increases Kp1 to 1.5 to accelerate the adjustment response; if the adjustment is too low and the speed still doesn't improve, further adjustments may be necessary. <4℃ / min, prioritize adjusting the outlet pressure of the hot salt pump (6) to 1.2-1.5MPa, and then adjust the cold salt injection rate.

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