CN114077271B - A high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform and experiment method - Google Patents

Abstract

A high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform, including a high-temperature chloride salt test system, an energy storage system, an electric heating system, a thermal insulation system, a solar simulation system, a salt injection system, a salt discharge system, and a storage tank Air isolation system and data acquisition and control system. The purpose of the invention is to verify the reliability of the operation of the experimental platform when the working temperature is 565-700 ° C, to carry out research on the light-heat-mechanical coupling mechanism of the heat absorber under different light intensities and operating conditions, and the corrosion performance of chloride salts on different metals. The air isolation system of the storage tank was designed to reduce the corrosion of chloride salt during system operation; the energy storage system was designed to study the energy storage effect of chloride salt at high temperature; the salt discharge system was designed to avoid the corrosion of chloride salt after the experiment clogged pipes. This experimental platform can evaluate the high-temperature chloride salt corrosion problem faced by the next generation of solar thermal power generation technology, and screen out the applicability of experimental equipment with different materials and structures in the next generation of solar thermal power generation technology.

Description

A high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform and experiment method

technical field

The invention belongs to the technical field of solar heat utilization, and in particular relates to a high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform and an experiment method.

Background technique

With the rapid development of the world economy, people's living standards and quality of life are constantly improving, and the demand for energy is also increasing. The supply of traditional fossil energy is gradually in crisis. On the other hand, the massive consumption of traditional fossil energy has caused serious environmental pollution problems, such as the hole in the ozone layer over Antarctica and global warming, which have adversely affected human survival and safety. In order to coordinate the contradiction between human pursuit of a better life and the shortage of traditional energy supply and environmental pollution, accelerate the peaking of carbon dioxide emissions, and achieve "zero carbon dioxide emissions" as soon as possible, the development of renewable energy has gradually entered the field of vision of mankind. However, the development status of renewable energy cannot fully meet human needs. In order to realize the sustainable development of human society, the balance of energy consumption needs to gradually shift to renewable energy, and the development of renewable energy is receiving increasing attention.

There are many types of renewable energy, including solar energy, wind energy, hydro energy, tidal energy, biomass energy, geothermal energy, etc. Among them, solar energy reserves are the most abundant. Taking the solar radiation intercepted by the earth as an example, there is 1.73×10 ¹⁷ W of energy per second, which is equivalent to burning 5.9×10 ⁶ tons of coal. After the solar energy is collected, it can be used for heating, power supply and other fields. With the continuous development of solar energy utilization technology, the advantages of solar energy in the renewable energy system are becoming increasingly prominent. At present, in the field of solar power generation, there are mainly two forms of utilization, namely solar photovoltaic power generation and solar thermal power generation. The difference between the two is that photovoltaic power generation can realize the direct conversion of light energy to electric energy, while solar thermal power generation first converts solar energy into heat energy, and then uses the high-temperature working fluid obtained by heat to drive the turbine to generate power. Relatively speaking, photovoltaic power generation is greatly affected by weather changes, and it is difficult to connect to the grid, while solar thermal power generation is less affected by weather changes because of its energy storage system, which can be used for peak and valley regulation of the power grid and is suitable for centralized Energy supply has a good development prospect.

With continuous development, solar thermal power generation technology can be mainly divided into two types: line-focused and point-focused. Among them, the focused energy flux density of the line-focused solar thermal power plant is relatively small, the working temperature of the medium is generally lower than 500°C, and the power generation efficiency is relatively low. Point-focused solar thermal power plants can be mainly divided into tower solar power plants, dish solar power plants and other types. Among them, tower-type solar power plants are more popular because they can be combined with energy storage systems and can achieve stable output of electric energy. As an important part of tower-type solar thermal power generation technology, the energy storage system realizes the separation of light-to-heat conversion and thermoelectric conversion, and the power generation process is no longer affected by the intermittency and instability of solar energy. Stable power generation, and the power generation can be adjusted according to user needs. It has the characteristics of low power generation cost and strong peak-shaving capability.

In order to achieve lower electricity costs and higher thermal power conversion efficiency, the temperature of the evaporation section of the thermal conversion system can be increased, but this puts forward higher requirements on the stability of the thermal power conversion working medium at high temperatures. Supercritical carbon dioxide Brayton cycle power generation technology has the advantages of stable chemical properties of the circulating working fluid, compact system structure, and high cycle efficiency at high temperatures, which can meet the above requirements. In order to realize the combination of solar thermal power generation technology and supercritical carbon dioxide Brayton cycle power generation technology and promote the development of next-generation solar thermal power generation technology, the temperature of the working medium in the heat absorber needs to reach 520-720 °C or even higher. The tower-type solar thermal power generation system has the characteristics of high concentration ratio and large focused energy flow, and can be well matched with supercritical carbon dioxide Brayton cycle power generation technology. At present, tower-type molten salt power plants that have been built and put into commercial operation generally use solar salt (60% NaNO ₃ -40% KNO ₃ ) as the working medium, with a melting point of 220°C and an operating temperature of 290-565°C. When the working temperature exceeds 600°C, the molten salt will decompose, which is not suitable for the working temperature requirements of the next generation of solar thermal power generation technology. If it is combined with the supercritical carbon dioxide Brayton cycle power generation technology, the supercritical carbon dioxide Brayton cycle cannot be used. Advantages of power generation technology, low power generation efficiency. Molten chloride salts (such as MgCl ₂ -KCl-NaCl) have excellent thermal properties, high thermal stability, and low price, so the application in the next generation of solar thermal power generation technology is quite promising. However, molten chloride salts are highly corrosive to metal materials such as alloys at high temperatures. Higher requirements are put forward, which also poses challenges to the safe operation of the system. In addition, higher working temperature requires greater energy flux density, resulting in greater thermal stress, which may cause heat absorber coating to burn, heat absorber tube breakage, etc. The selection of heat absorber material and form structure The design presents even more serious challenges.

At present, laboratory-level tower-type solar thermal conversion systems mostly use nitrate with an operating temperature lower than 565°C as the working medium, and the heating method is mostly electric heating simulation, and less consideration is given to energy storage systems. For the next generation of solar thermal power generation technology , the lack of energy storage systems coupled with supercritical carbon dioxide heat exchange and the high temperature and corrosion problems caused by the use of chloride salts, the selection of high temperature and corrosion resistant materials, the design of salt injection systems, the design of equipment and instruments, and the research on control strategies , the electric heating method cannot well simulate the heating effect of solar energy focusing non-uniform energy flow. In order to promote the development of the next generation of solar thermal power generation technology, it is urgent to carry out the tower solar cycle simulation and energy storage system experimental research based on chloride salt, to explore the reliability of the system operation when the working temperature is as high as 565-700 ℃, and the different light intensities , The optical-thermal-mechanical coupling mechanism of the experimental system under different operating conditions, and the influence of high-temperature chloride salt on the corrosion performance of different metals was detected and analyzed during the operation of the system.

Contents of the invention

The invention provides a high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform and an experimental method to carry out the high-temperature chloride salt heat absorber indoors when the outlet temperature is 565-700°C under non-uniform energy flow density. Research on the photothermal-mechanical coupling mechanism and the corrosion performance of chloride salts on different metals, research on the photothermal-mechanical coupling mechanism of the system, the type of molten salt, the material of the heat absorber, the coating of the heat absorber, the structure of the heat absorber, and the strengthening structure of the heat absorber tube, etc. The influence of the performance of the energy storage system and the thermal stress failure mechanism of the heat absorber under the condition of extreme non-uniform energy flow, the influence of unsteady and non-uniform energy flow on the temperature distribution of the outer wall of the heat absorber, and the dynamic performance of the outlet temperature of the heat absorber Prediction method, combined with validation of receiver operational reliability.

A high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform, including a high-temperature chloride salt test system, an energy storage system, an electric heating system and a sunlight simulation system;

The high-temperature chloride salt test system includes a first salt storage tank. A first molten salt pump is installed on the first salt storage tank. The input end of the first molten salt pump extends into the first salt storage tank, and the output One end is connected to the first end of the chloride salt input channel, the second end of the chloride salt input channel is connected to the second salt storage tank, and a heat absorber is installed on the chloride salt input channel;

The energy storage system includes a second salt storage tank, and an intermediate heat exchanger is installed on the chloride salt return channel for heat exchange between the high-temperature chloride salt from the second salt storage tank and supercritical carbon dioxide; A second molten salt pump is installed on the second salt storage tank, the input end of the second molten salt pump extends into the second salt storage tank, the output end is connected to the first end of the chloride salt return channel, and the chlorine The second end of the salt return channel is connected to the inlet end of the first salt storage tank;

A throttling member and a first differential pressure sensor are installed on the chloride salt input channel, and the first differential pressure sensor is connected to both ends of the inlet and outlet of the throttling member through the first differential pressure detection channel, and is used to measure the pressure at both ends of the throttling member. Differential pressure;

The electric heating system includes heating elements arranged outside the first salt storage tank and the second salt storage tank, and heat tracing equipment arranged outside the chloride salt input channel and the chloride salt return channel;

The solar simulation system includes a solar simulator, a dynamometer, a video camera and a Lambertian target, the dynamometer is located at the center of the Lambertian target, the solar simulator is facing the Lambertian target, and the camera is placed on one side of the solar simulator and faces Lambertian target; both the Lambertian target and the solar simulator are arranged on the front of the heat absorber, and the camera is used to take photos of the light intensity distribution on the Lambertian target.

The high-temperature chloride salt photothermal and energy storage cycle experiment method based on the above-mentioned experimental platform includes the following steps:

Step 1. Place the energy flow meter at the focal point of the solar simulator, and cool down the Lambertian target and the energy flow meter; draw the position coordinates of the test point on the Lambertian target, turn on and debug the solar simulator, so that the Lambertian target forms Focused energy flow spot, the center of the focused energy flow is located at the energy flow meter; take photos of the light intensity distribution of the Lambertian target, and record the energy flow value measured by the energy flow meter;

Turn off the solar simulator, move the Lambertian target so that the energy flow meter is located at the spatial coordinates of each test point in turn, turn on the solar simulator, take photos of the light intensity distribution of the Lambertian target, and record the energy flow value measured by the energy flow meter;

Bring the energy flow value and gray value of each test point into the functional relationship between the two, and solve the coefficients in the functional relationship;

Step 2. Remove the Lambertian target, place the heat absorber at the focal point of the solar simulator, discharge the air in the first salt storage tank and the second salt storage tank, and discharge the ternary chloride salt MgCl ₂ -KCl-NaCl Inject into the first salt storage tank for standby, keep the first salt storage tank and the second salt storage tank as being filled with argon, and isolate the air;

Step 3. Heat the chloride salt in the first salt storage tank to the target temperature by means of step-by-step heating; simultaneously, heat the chloride salt circulation pipeline to a set temperature, which is greater than that of the ternary chloride salt. Melting point; after the temperature of the chloride salt and the pipeline is stable, start the solar simulator, so that the face of the heat absorber receives the radiation of the solar simulator; turn on the infrared thermal imager, and monitor the surface temperature distribution of the heat absorber;

When the temperature of the outer wall surface of the pipe of the heat absorber reaches the set value, the first molten salt pump is turned on to deliver the chloride salt, and the flow value of the chloride salt is monitored in real time, and the motor frequency of the first molten salt pump is adjusted according to the flow value , so that the flow rate of chloride salt reaches the set value;

Step 4. When the entire experimental platform is in a thermal equilibrium state, start recording the chloride salt temperature at the inlet and outlet of the heat absorber, the light intensity information of the light-facing surface of the heat absorber, and the temperature of the light-facing surface of the heat absorber every set time distribution, the temperature distribution of the backlight surface of the heat absorber, the volume flow rate of chloride salt, the pressure difference between the inlet and outlet of the heat absorber, the liquid level height in the first salt storage tank, the chloride salt temperature in the first salt storage tank and The temperature of chloride salt in the second salt storage tank is recorded for 30 to 60 minutes;

Step 5, disconnect the power supply of the first molten salt pump, and turn on the heat tracing equipment, so that the chlorinated salt in the heat absorber flows back into the first salt storage tank and the second salt storage tank; Thermal equipment, resistance wire heating elements;

Step 6. Calculate the incident radiant energy provided by the solar simulator to the heat sink according to the light intensity information on the light-facing surface of the heat sink and the functional relationship between the energy flow value and the gray value obtained in step 1; Calculate the heat absorbed by the chloride salt when the chloride salt flows in the heat absorber based on the recorded temperature of the inlet and outlet chloride salt of the heat absorber and the volume flow rate of the chloride salt; combine the incident radiant energy to calculate the heat loss and thermal efficiency of the heat absorber; According to the liquid level height and chloride salt temperature in the first salt storage tank and the chloride salt temperature in the second salt storage tank, calculate the heat obtained by the supercritical carbon dioxide in the actual tower power station through the intermediate heat exchanger; use heat absorption The thermal stress analysis of the heat sink is carried out based on the temperature distribution of the light-facing surface of the heat sink and the temperature distribution of the back-light surface of the heat sink.

Compared with the prior art, the present invention has at least the following beneficial technical effects:

1. The experimental platform of the present invention can carry out photothermal coupling experiments of non-uniform energy flow high-temperature chloride salt heat absorbers under the action of solar simulators in the laboratory, compared with the existing electric heating simulation of non-uniform energy flow conditions The experimental platform is more suitable for the actual situation. On the basis of the completion of the experiment, it is possible to further carry out the experiment of simulating the tower-type solar concentrating heat collection system under various temperature conditions combined with other molten salt types, and the photothermal The experiment of coupling performance can also be used to carry out the experiment of testing the corrosion performance of metals of different materials in a high-temperature chloride salt environment. The experimental platform has a wide range of applications and good adaptability.

2. The high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform provided by the present invention uses the second salt storage tank as the high-temperature energy storage tank to realize effective storage of heat energy for high-temperature chloride salt. Compared with traditional nitrates, chloride salts have higher working temperature, higher energy storage density, better thermal stability, and better heat storage performance. In view of the strong corrosiveness of chloride salt, Haynes 230 is selected as the material of the second salt storage tank in the energy storage system, and an air isolation system for the storage tank is designed on the second salt storage tank to reduce the corrosiveness of chloride salt. During the experiment, the second salt storage tank was used as a high-temperature energy storage tank to store the irradiated high-temperature chloride salt. Before the next experiment, the high-temperature salt in the second salt storage tank was pumped to The chloride salt is delivered to the first salt storage tank, which reduces the power consumption required for heating the chloride salt;

3. In the high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform provided by the present invention, the circulating working medium is ternary chloride salt MgCl ₂ -KCl-NaCl (mole: 68.2-17.8-14%). Compared with the binary nitrate NaNO ₃ -KNO ₃ used in the current tower solar power plants, chloride salt has a higher melting and decomposition temperature, lower price, but more corrosive. Based on this, Haynes 230 with excellent thermal stability and corrosion resistance was selected as the first salt storage tank, the second salt storage tank, the input channel of chloride salt, the return channel of chloride salt, the discharge channel of chloride salt, the first differential The material of the pressure detection channel, the second differential pressure detection channel, etc.

Currently built tower solar power plants usually use immersion electric heaters to heat the binary nitrate NaNO ₃ -KNO ₃ (mole:60-40%), but using immersion electric heaters to heat chloride salts will be affected Due to the dual challenges of high temperature and strong corrosion, it is difficult to operate for a long time if the immersion electric heaters made of conventional 310s and 800 alloys are used, and the price is relatively expensive if the electric heaters are made of nickel-based alloys such as Haynes 230. This experimental platform adopts Resistance furnace, using the resistance wire heating element of the resistance furnace to preheat the chloride salt in the first salt storage tank and the second salt storage tank to the set temperature, avoiding the direct contact between the electric heater and the chloride salt, and using The heat tracing equipment preheats the pipeline to prevent the chloride salt from freezing and solidifying when flowing through the pipeline and blocking the pipeline.

4. In the high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform provided by the present invention, a salt injection tank is designed to transport purified chloride salt to the first salt storage tank. During transportation, the chloride salt in the salt injection tank is in an argon sealed environment of about 0.01MPa to prevent outside air from infiltrating into the salt injection tank; when injecting salt from the salt injection tank to the first salt storage tank, by increasing the The argon pressure in the salt tank realizes the transfer process of the chloride salt. Air pollution to chloride salt during transportation and salt injection is avoided.

5. In the present invention, a chloride salt discharge channel is designed at the bottom of the heat absorber, which avoids the accumulation of chloride salt at the bottom of the heat absorber when the salt is discharged after the experiment is completed. All pipelines on the experimental platform are equipped with an inclination angle of 3-5°, and argon gas is used to assist salt removal, which effectively reduces the possibility of residual chloride salts on the pipelines. The first salt storage tank of the experimental platform is wrapped with thermal insulation material to maintain the stability of the temperature of the chloride salt during the experiment, and it is used as a heat storage tank after the experiment to reduce the heat loss of the chloride salt, so that the next experiment can provide more Less heat heats the chloride salt to the set temperature, reducing power consumption.

6. The present invention adopts the sunlight simulation system as the radiant energy source of the heat absorber, and realizes the simulation of real sunlight with non-uniform light-gathering characteristics. In addition, real sunlight is greatly affected by meteorological conditions. The use of sunlight simulation system eliminates the adverse effects of outdoor weather changes and environmental factors on the experimental platform, and realizes different light intensities, operating conditions, Effects of molten salt type, heat absorber material, heat absorber coating, heat absorber structure, and heat absorber tube strengthening structure on the optical-thermal-mechanical coupling mechanism of the heat absorber, the performance of the energy storage system, and the chloride salt under different operating conditions Research on the corrosion performance of the heat absorber and the thermal stress failure mechanism of the heat absorber under the condition of extreme non-uniform heat flow, analyze the influence of unsteady and non-uniform energy flow on the temperature distribution of the outer wall of the heat absorber, and explore the dynamic performance prediction method of the heat absorber outlet temperature .

7. The present invention adopts the data acquisition and control system to realize the data acquisition of the entire experimental system and the remote control of the resistance wire heating element, the first molten salt pump, the first Y-type electric stop valve, etc., and through the experimental power distribution cabinet for Solar simulator, the first molten salt pump, the second molten salt pump, resistance wire heating elements, 6 Y-type electric globe valves, 2 differential pressure sensors, 2 pressure sensors, throttling parts, radar level gauges, etc. electrical energy. The experimental computer in the data acquisition and control system is self-programmed by LabVIEW software, and the temperature at the inlet of the heat absorber, the power of the resistance wire heating element, the power of the 6 Y-type electric motors, and the temperature collected by the first N-type thermocouple passed by the data acquisition cabinet are collected. Information such as the opening and closing of the shut-off valve is visualized, and the experimenters can remotely control the entire system after issuing operation commands through the PLC on the experimental computer, such as controlling the opening and closing of 6 Y-shaped electric shut-off valves. The experimental control cabinet in the data acquisition and control system is equipped with a power supply start-stop module, a solar simulator power regulation module, a heating system power regulation module, a molten salt pump frequency conversion regulation module, etc., which can realize the control of the solar simulator, the first Switch control of molten salt pump, second molten salt pump, resistance wire heating element, heat tracing equipment, etc., and adjustment of chloride salt flow rate, temperature, etc. The experimental control cabinet can realize the manual control of each equipment, which reduces the risk caused by the sudden failure of the remote control system and other emergency situations, and ensures the safe operation of the experimental system.

Further, in the high-temperature chloride salt test system, a certain number of thermocouples are set from the center of the top cover plate of the first salt storage tank to the inner wall of the tank to ensure that the temperature distribution of chloride salt in the storage tank is uniform at the end of each heating stage And it is stable, and the temperature signal is fed back to the data acquisition and control system to realize the control of the power of the resistance wire heating element and the switch of the first molten salt pump. The thermocouple probe is inserted from the top cover plate of the first salt storage tank to a distance of 50-100 mm from the bottom head to prevent the temperature drop of the chloride salt liquid level during the experiment from exposing the thermocouple probe to the outside of the liquid surface; The frequency of the frequency converter of the salt pump motor adjusts the pumping flow; a radar level gauge is installed on the top of the first salt storage tank to monitor the material level value in the first salt storage tank.

Further, a certain number of thermocouples are set from the center of the top cover plate of the second salt storage tank in the energy storage system to the inner wall of the tank to monitor the temperature distribution of the chloride salt in the second salt storage tank in real time, and the temperature The signal is fed back to the data acquisition and control system to realize the control of the resistance wire heating element and the second molten salt pump. Wherein, the pumping flow rate of the second molten salt pump is adjusted by setting the frequency of the frequency converter of the motor. The thermocouple probe is inserted from the top cover plate of the second salt storage tank to a distance of 50-100mm from the bottom head.

In addition, the liquid level value of the second salt storage tank is calculated according to the liquid level value in the first salt storage tank and the amount of molten salt in the pipeline. The radar level gauge can prevent the chloride salt level in the first salt storage tank and the second salt storage tank from being too low during the experiment, causing damage to the first molten salt pump and the second molten salt pump due to idling; the first salt storage tank A throttling piece is installed on the chloride salt input channel between the tank and the heat absorber inlet, and the throttling piece and the first differential pressure sensor connected to it together form a differential pressure flowmeter, and the measured value of the differential pressure flowmeter The flow value is used as a feedback signal to adjust the frequency of the first molten salt pump, and also used as a feedback signal to control the first molten salt pump, the second Y-type electric stop valve, the third Y-type electric stop valve, the fifth Y-type electric stop valve, the companion On and off of thermal equipment. When the flow value measured by the differential pressure flowmeter decreases abnormally, the throttling member is likely to be blocked. At this time, the salt discharge system is started, that is, the first molten salt pump and the third Y-type electric stop valve are turned off, and the heat tracing is turned on. Equipment, the second Y-type electric globe valve, the third Y-type electric globe valve, the fifth Y-type electric globe valve, the first two-way ball valve, the second two-way ball valve, and adjust the first three-way ball valve so that it points to the first One or two-way ball valve, open the first argon cylinder to discharge salt; the second differential pressure detection channel is equipped with a third high temperature diaphragm flange, a third cooling fin, a third medium and low temperature diaphragm flange, a second differential pressure sensor, The fourth medium and low temperature diaphragm flange, the fourth cooling fin, and the fourth high temperature diaphragm flange are connected to the inlet and outlet of the heat absorber through the fourth three-way joint and the fifth three-way joint for measuring the heat absorber inlet and outlet Differential pressure value, according to the differential pressure value, it is judged whether the heat absorber is blocked or leaked, and it is used as a feedback signal to control the second Y-type electric stop valve, the third Y-type electric stop valve, the fifth Y-type electric stop valve and heat tracing equipment on and off. If the differential pressure value measured by the second differential pressure section increases or decreases abnormally, it is judged that the heat absorber may be blocked or leaked, and the salt discharge system is started; the inlet and outlet of the heat absorber are respectively equipped with the first N-type thermocouple and The second N-type thermocouple, the measured inlet and outlet temperature of the heat absorber is used to calculate the thermal efficiency of the heat absorber; the facing surface of the heat absorber is directly radiated by the solar simulator, and the temperature is relatively high, and the temperature is measured by an infrared thermal imager Distribution; the backlight surface of the heat absorber is provided with several N-type thermocouples for measuring and obtaining the temperature distribution on the backlight surface of the heat absorber. According to the temperature distribution on the surface of the heat absorber, the thermal stress on the surface of the heat absorber is calculated and analyzed.

Further, the resistance wire heating element in the electric heating system is used to preheat the chloride salt to a set temperature, and a certain number of N-type thermocouples are arranged on the resistance wire heating element to prevent the resistance wire heating element from exceeding temperature. In order to ensure a good heating effect, the method of "variable power adjustment, step-by-step heating" is adopted. For example, the temperature of chloride salt is raised to 100°C as a stage. When heating in a certain stage, the resistance wire heating element automatically adjusts the power according to the temperature of the resistance wire heating element and the temperature of chloride salt. When the temperature of chloride salt reaches a stable level, it enters the next stage The temperature adjustment of the stages until the temperature of the chloride salt reaches the set temperature, at this time, the temperature of the chloride salt in the first salt storage tank is kept stable. When the chloride salt is solidified, since the thermal conductivity of the solid chloride salt is relatively poor, the heating power should not be too large to prevent the resistance wire heating element from overheating. The heating equipment in the electric heating system is adjusted by variable power. After the pipeline is heated to the set temperature, several thermocouples arranged on the pipeline will feed back the temperature signal to the experimental computer, and the experimental computer will issue an order to automatically adjust the power of the heating belt. , to maintain the stability of the pipeline temperature.

Further, the switch control of the feedwater pump and the solar simulator, the frequency of the feedwater pump and the power adjustment of the solar simulator are controlled by the control system, and the flow value of the electromagnetic flowmeter is collected. Turn on the feed water pump to make the cooling water flow in the water circulation pipeline to realize the cooling effect on the Lambertian target; after the solar simulator is turned on, adjust the power of the solar simulator through the control system to obtain different light intensity distributions.

Further, when the experiment ends or the molten salt leaks, the salt discharge system starts. Turn off the first molten salt pump and the third Y-type electric stop valve through the control system, the chloride salt loses the power provided by the molten salt pump, and the flow rate gradually slows down; turn on the heat tracing equipment to prevent the molten salt from solidifying in the pipeline; turn on the second The Y-type electric stop valve, the third Y-type electric stop valve, and the fifth Y-type electric stop valve use the set pipeline inclination angle of 3-5° to make the molten salt in the heat sink and the pipeline flow into the first salt storage tank and the first salt storage tank. in the second salt storage tank. In order to avoid the poor circulation of chloride salt, open the first two-way ball valve and the second two-way ball valve, and adjust the first three-way ball valve to point to the first two-way ball valve, open the first argon cylinder, and use argon to blow Sweep pipes to assist in salt discharge.

Further, the working process of the storage tank air isolation system is: open the third argon cylinder, the first electric ball valve, and the second electric ball valve, discharge the air in the first salt storage tank and the second salt storage tank, close the second Three argon cylinders, the first electric ball valve, and the second electric ball valve; open the second argon cylinder, and the first pressure sensor is used to measure the pre-valve pressure of the second self-operated argon inlet valve and the first self-operated argon inlet valve , the second pressure sensor measures the pressure in the first brine storage tank, and the third pressure sensor measures the pressure in the second brine storage tank. When the reading of the second pressure sensor is lower than the set value, it indicates that the pressure in the first salt storage tank is low, and at this time the second self-operated argon gas inlet valve is opened, and the argon gas enters the first salt storage tank; when the second When the reading of the pressure sensor is higher than the set value, the first self-operated argon discharge valve is opened, and the excess argon is discharged to the outside of the first salt storage tank; when the reading of the third pressure sensor is lower than the set value, It shows that the pressure in the second salt storage tank is low, at this moment, the first self-operated argon gas inlet valve opens, and the argon gas enters the second salt storage tank; when the reading of the third pressure sensor is higher than the set value, the second self-powered The type argon discharge valve is opened, and excess argon is discharged to the outside of the second salt storage tank.

Further, the data acquisition and control system is divided into two parts: a data module and a control module. The data acquisition module uses a data acquisition cabinet to collect radar level gauges, differential pressure flowmeters, second differential pressure sensors, and pressure transmitters. , the first N-type thermocouple, the second N-type thermocouple, the analog signals of several N-type thermocouple wires on the heat sink, etc., and simultaneously collect 6 Y-type electric stop valves, 2 molten salt pumps, and resistance wires The difference between digital signal, analog signal and digital signal of heating element, heating equipment, etc. is that the analog signal is a continuous signal in time and value, and the digital signal is a discrete signal in time and value. The control module is based on the PLC control unit. The PLC control unit receives the digital and analog signals input by the data acquisition module, and realizes the information transmission with the experimental control cabinet through RS485 communication. Instructions, the control of the entire system is realized through the PLC control unit.

In the test method described in the present invention, the focused non-uniform energy flow is applied to the heat absorber through the sunlight simulation system, which is more suitable for the actual concentrated solar radiation compared with the electric heating simulation system adopted by most test benches; The use of tank air isolation system reduces the corrosiveness of chloride salt, which is beneficial to the long-term safe operation of experimental equipment; the salt discharge system reduces the possibility of chloride salt blocking the channel during salt discharge; the data acquisition and control system realizes the The separation from the experimental equipment ensures the safety of the experimental personnel.

Description of drawings

Fig. 1 is a schematic diagram of the main structure of the present invention.

Fig. 2 is a schematic diagram of the solar light source simulation system of the present invention.

Fig. 3 is a schematic diagram of the storage tank air isolation system of the present invention.

Figure 4 is a schematic diagram of the structure of the heat sink and the arrangement of N-type thermocouple wires on the backlight surface in the experimental platform.

In the figure: 1—power distribution cabinet for experiment; 2—control cabinet for experiment; 3—data acquisition cabinet; 4—computer for experiment; 5—first argon purge channel; 6—first tee joint; 7— One branch of the first argon purging channel; 8—two branches of the first argon purging channel; 9—the first two-way ball valve; 10—the second two-way ball valve; 11—heat tracing equipment; 12—the first Three-way ball valve; 13—the first Y-type electric stop valve; 14—the common section of the two branches of the pressure release channel/the first argon purge channel; 15—the second self-operated argon gas inlet valve; 16—the second pressure sensor ; 17—the first argon cylinder; 18—the first pressure sensor; 19—the second argon gas purging channel; 20—the second three-way joint; 21—the second branch of the second argon gas purging channel; 22—the first A self-operated argon inlet valve; 23—the third pressure sensor; 24—a branch of the second argon purge channel; 25—radar level gauge; 26—the first molten salt pump; 27—the first safety valve; 28—the first self-operated argon discharge valve; 29—the first electric ball valve; 30—the return channel of chloride salt; 31—the second Y-type electric stop valve; 32—the third three-way joint; 33—input of chloride salt Channel; 34—the third Y-type electric stop valve; 35—the first high temperature diaphragm flange; 36—the first cooling fin; 37—the first medium and low temperature diaphragm flange; 38—the first differential pressure sensor; 39—the first Second medium and low temperature diaphragm flange; 40—the second cooling fin; 41—the second high temperature diaphragm flange; 42—the first differential pressure detection channel; 43—throttle piece; 44—the fourth three-way joint; 45—the first 1. N-type thermocouple; 46—heat absorber; 47—N-type thermocouple wire; 48—the third high-temperature diaphragm flange; 49—the third cooling fin; 50—the third medium and low temperature diaphragm flange; 51—the first Second differential pressure sensor; 52—the fourth medium and low temperature diaphragm flange; 53—the fourth cooling fin; 54—the fourth high temperature diaphragm flange; 55—the second differential pressure detection channel; 56—the second N-type thermocouple; 57—the fifth three-way joint; 58—the second safety valve; 59—the second molten salt pump; 60—the second self-operated argon discharge valve; 61—the second electric ball valve; 62—the second argon cylinder; 63 —the third argon cylinder; 64—the third argon purging channel; 65—the sixth tee joint; 66—one branch of the third argon purging channel; 67—two branches of the third argon purging channel ;68—the fourth Y-type electric stop valve; 69—the first molten salt tank support frame; 70—the fifth Y-type electric stop valve; 71—chloride salt discharge channel; 72—Lambertian target; 73—solar simulator; 74—insulation material; 75—resistance wire heating element; 76—the first salt storage tank; 77—the first molten salt tank; 78—the return channel of chloride salt; 79—the second molten salt tank; 80—the second molten salt tank Salt tank support frame; 81—second salt storage tank; 82—sixth Y-type electric stop valve; 83—infrared thermal imager; 84—intermediate heat exchanger; 85—salt injection port; 86—energy flow meter; 87 —feed water pump; 88—cooling water tank; 89—electromagnetic flowmeter; 90—camera; 91—water circulation pipeline; 92—salt injection channel ;93—pressure transmitter; 94—salt inlet; 95—salt outlet; 96—the first gate valve; 97—pressure stabilization channel; 98—vacuum pump; 99—the second gate valve; Channel; 101—the fourth argon cylinder; 102—the salt injection tank; 103—the support frame of the salt injection tank; 104—the third molten salt tank.

Detailed ways

In order to make the purpose and technical solution of the present invention clearer and easier to understand. The present invention will be further described in detail below in conjunction with the drawings and embodiments. The specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The invention provides a high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform, where the high-temperature chloride salt refers to the ternary chloride salt MgCl ₂ -KCl-NaCl (mole:68.2- 17.8-14%), and its melting point is 380°C. Considering that the purpose of this experimental platform is to study the operation reliability of high-temperature molten salt heat sinks with an outlet temperature of 565-700°C, and to reveal the light-heat coupling under non-uniform energy flux density The heat transfer mechanism, thermomechanical coupling and failure mechanism need to solve the following main difficulties:

1. How to deal with the impact of the strong corrosiveness of chloride salt on the experimental system. The ternary chloride salt MgCl ₂ -KCl-NaCl (mole: 68.2-17.8-14%) used in the experimental system has good stability at high temperature, large specific heat capacity and low viscosity, which meets the requirements of high temperature heat transfer and heat storage. However, the ternary chloride salt MgCl ₂ -KCl-NaCl (mole: 68.2-17.8-14%) has strong corrosiveness, and the corrosiveness gradually increases as the temperature increases. In the corrosion process of the ternary chloride salt MgCl ₂ -KCl-NaCl (mole: 68.2-17.8-14%), the oxidant is usually O ₂ , H ₂ O, etc. in the air. Taking O ₂ as an example, in the atmospheric environment, Cl ^-1 in the ternary chloride salt MgCl ₂ -KCl-NaCl (mole: 68.2-17.8-14%) will be oxidized to Cl ₂ , and Cl ₂ and Fe and other metals The matrix reacts to form metal chlorides such as _FeCl2 , _and metal chlorides such as _FeCl2 react with _O2 to form metal oxides such as _Fe2O3 . In order to cope with the strong corrosion of chloride salt, on the one hand, for the components that are in direct contact with chloride salt, such as the first salt storage tank, the second salt storage tank, the input channel of chloride salt, the return channel of chloride salt, the chlorination salt For salt discharge channels, etc., choose Haynes 230 alloy, which has high Ni and Gr content, so it has excellent corrosion resistance. On the other hand, the storage tank air isolation system is used to isolate the air and reduce the content of O ₂ , H ₂ O, etc. in the first salt storage tank, the second salt storage tank and pipelines, thereby reducing the corrosiveness of chloride salt. The air isolation system of the storage tank needs to open the third argon gas bottle before injecting the chloride salt, and send air to the first salt storage tank and the second salt storage tank through the fourth Y-type electric stop valve and the sixth Y-type electric stop valve. Inject argon gas inside, and discharge the air in the first salt storage tank and the second salt storage tank to the external environment through the first electric ball valve and the second electric ball valve. The argon gas retained in the tank ensures that the first salt storage tank and the argon in the second salt storage tank to protect the environment; during the experiment, through the second self-operated argon inlet valve, the first self-operated argon discharge valve, the first self-operated argon inlet valve, the second self-operated argon The argon discharge valve is used to supplement and discharge argon to maintain the pressure stability in the first salt storage tank and the second salt storage tank. Through the above two measures, the adverse effect of the corrosiveness of the ternary chloride salt MgCl ₂ -KCl-NaCl (mole: 68.2-17.8-14%) on the experimental platform can be reduced to the greatest extent, ensuring the safety of the experiment.

2. The temperature of the chloride salt on this experimental platform reaches a maximum of 700°C, while the temperature resistance range of most measuring instruments is lower than 500°C. How to deal with this contradiction to ensure the normal use of the measuring instruments. For the radar level gauge installed on the top cover of the first salt chloride tank, it can only withstand a maximum of 200°C, while the temperature of the chloride salt in the first salt storage tank may be as high as 700°C. Install a thermal insulation device in the position meter. Specifically, microwave-permeable high-temperature-resistant quartz glass is installed under the radar probe of the radar level gauge; The receiving temperature is only 150°C, which is far lower than the working temperature of chloride salt. The pressure difference is transmitted between the differential pressure sensor and the chloride salt through heat transfer oil, and then the measured pressure difference signal is converted into an electrical signal output. If the temperature of the heat transfer oil in contact with the differential pressure sensor can be reduced, the application range of the differential pressure sensor can be increased. In order to reduce the heat transfer oil temperature, two measures have been taken. First, on the first differential pressure detection channel, a first high-temperature diaphragm flange, a first medium-low temperature diaphragm flange, a second high-temperature diaphragm flange, and a second medium-low temperature diaphragm flange are arranged. Wherein, the first high-temperature diaphragm flange and the second high-temperature diaphragm flange are in contact with the chloride salt. The fluid pressure on both sides of the diaphragm flange is normally transmitted, but there is a large heat loss. In order to further reduce the temperature of the heat transfer oil, a first cooling fin is provided between the first high-temperature diaphragm flange and the first medium-low temperature diaphragm flange, and a cooling fin is provided between the second high-temperature diaphragm flange and the second medium-low temperature diaphragm flange There are second cooling fins to increase the heat loss of the heat transfer oil and reduce the temperature of the heat transfer oil connected to the sensor. The processing method on the second differential pressure detection channel is the same as that of the first differential pressure detection channel.

3. How to transport the purified chlorinated salt to the first salt storage tank, and prevent the air from polluting the chlorinated salt during the transport process. The transportation process here includes two links. The first link is to transport the purified chloride salt to the vicinity of the experimental platform. This link is realized by salt injection tank. Before injecting chloride salt into the salt injection tank, use the vacuum pump and the fourth argon cylinder to discharge the air in the salt injection tank to ensure the argon environment in the salt injection tank, and then inject chloride salt into the salt injection tank; During the transportation process, the chloride salt in the salt injection tank is in a closed environment of about 0.01MPa argon gas; the second link is to transport the chloride salt from the salt injection tank to the first salt storage tank. This link is realized through the salt injection channel connecting the salt injection tank and the first salt storage tank. After the connection of the salt injection channel is completed, inject 0.03-0.05MPa argon gas into the salt injection tank through the fourth argon gas cylinder, and realize the delivery of chloride salt under the action of the pressure of the argon gas.

4. How to prevent the chlorinated salt from solidifying and blocking the pipeline during the flow process in the pipeline. The chloride salt here refers to the ternary chloride salt MgCl ₂ -KCl-NaCl (mole: 68.2-17.8-14%), its melting point is 380°C, which is much higher than the ambient temperature, and there is a possibility of solidification during the flow process sex. If the chloride salt solidifies, the entire system needs to be shut down, and the chloride salt at this position will be treated with salt, which will have a bad impact on the progress of the experiment. In order to reduce the possibility of chloride solidification, this experimental platform takes three measures. One is to lay thermal insulation materials on the outer wall of the pipeline through which the chloride salt passes, such as the chloride salt input channel, the chloride salt return channel, the chloride salt return channel, the chloride salt discharge channel, the first differential pressure detection channel, the second Differential pressure detection channels, etc., and ensure that the temperature of the outer wall of the insulation material is below 50°C; the second is to lay heat tracing equipment on the outer wall of the channel where the above-mentioned chloride salt passes, and the insulation material is laid on the outside of the heat tracing equipment. Before the chloride salt is introduced into the pipeline, the temperature of the outer wall surface of the pipeline is heated to 50°C above the melting point of the ternary chloride salt MgCl ₂ -KCl-NaCl (mole:68.2-17.8-14%) through the heating equipment, and the temperature is maintained Stablize. When the chloride salt is passed into the pipeline, turn off the heating equipment to avoid affecting the experimental results; the third is to set an inclination angle of 3-5° for the pipeline through which the chloride salt passes, and at the same time pass the first argon gas purging branch The first argon purge channel, one branch of the first argon purge channel, the second branch of the first argon purge channel, etc., feed argon into the heat absorber, and discharge salt under the double action of gravity and argon auxiliary purge. Avoid clogging when draining salt.

5. The working temperature of the tower type molten salt power station is generally 290-565°C. The working temperature of the chloride salt in this experimental platform reaches a maximum of 700°C, and it is highly corrosive. It is very important to ensure the safety of the experimental platform. The experimental platform adopts the data acquisition and control system to remotely operate the experimental platform, and installs monitoring equipment in the laboratory to monitor the situation in the laboratory at any time, avoiding the danger caused by the close contact between the experimental personnel and the equipment. If the first salt storage tank leaks, the fourth Y-shaped electric stop valve placed at the bottom of the first salt storage tank is opened through the data acquisition and control system, so that the chloride salt in the first salt storage tank flows into the first molten salt in the slot. If the second salt storage tank leaks, the sixth Y-type electric stop valve placed at the bottom of the second salt storage tank is opened through the data acquisition and control system, so that the chloride salt in the second salt storage tank flows into the second molten salt in the slot. The first molten salt pump, the second molten salt pump, and the resistance wire heating element are all equipped with an over-temperature protection module. If the flow rate of the throttle part decreases abnormally, the pressure detected by the second differential pressure transmitter increases or decreases abnormally. , then immediately alarm and stop the operation of the experimental system.

6. How to heat the molten salt in the first salt storage tank to the design temperature and keep it uniform and stable. The resistance wire heating element is used to provide heat for the experimental system. The resistance wire heating element and the outer wall of the first salt storage tank are provided with N-type thermocouples. There are several thermocouples arranged in the first salt storage tank. The thermocouple probe is inserted from the top cover plate of the first salt storage tank to a distance of 50-100mm from the bottom head. When heating chlorinated salt, the method of "variation of power adjustment, step by step heating" is adopted. For example, if the heating temperature is set to 600°C, the heating process is divided into 5 stages, the first stage is 380°C (melting point temperature), the second stage is 500°C, the third stage is 560°C, the fourth stage is 580°C, and the fourth stage is 580°C. The fifth grade is 600°C. For the first-level adjustment, set the temperature of the outer wall of the first salt storage tank to 380°C, and start the resistance wire heating element. When the temperature of the outer wall of the first salt storage tank is close to 380°C, the data acquisition and control system will issue an instruction to automatically adjust The power of the resistance wire heating element is used to maintain the temperature of the outer wall of the first salt storage tank at about 380°C, and at the same time observe the temperature of chloride salt in the first salt storage tank. When the temperature of each thermocouple in the first salt storage tank is stable, enter the next level of regulation. The second-level adjustment, the third-level adjustment, and the fourth-level adjustment are the same as the first-level adjustment. For the fifth-level adjustment, set the temperature of the outer wall of the first salt storage tank to 600°C, and the data acquisition and control system will issue instructions to automatically adjust the power of the resistance wire heating element, so that the temperature of the outer wall of the first salt storage tank is stable at about 600°C , while observing the chloride salt temperature in the first salt storage tank. When the temperature of the thermocouples in the first salt storage tank is stable, set the temperature of the thermocouples arranged in the center of the first salt storage tank to 600°C, and when the temperature of the thermocouples in the first salt storage tank reaches stability again, start The first molten salt pump makes the molten salt flow. It should be noted that when setting the temperature levels of each level, the higher the temperature, the smaller the temperature difference between each level. This is because as the set temperature increases, the higher the temperature the resistance wire heating element can reach when operating at high power, the greater the risk of overheating. Reducing the temperature difference at each level is conducive to making the electric heater element run more at low power, and effectively avoiding the overheating of the resistance wire heating element.

7. How to obtain the temperature distribution on the light-facing surface of the heat sink. The temperature of the light-facing surface of the heat absorber is measured during the experiment, one is to prevent the wall of the heat absorber from overheating; the other is to calculate the thermal stress. There are two ways to obtain the temperature distribution of the heat sink facing the sun. One is direct measurement, that is, a certain number of thermocouple wires are arranged on the light-facing surface of the heat sink; the other is indirect measurement, and an infrared thermal imager is used at this time. If direct measurement is used, the measurement accuracy is more accurate, but more thermocouple wires are arranged on the light-facing surface of the heat sink, which may block the heat sink from receiving solar radiation. In addition, the focused energy flow of the solar simulator may also cause the burning of the thermocouple wire; if indirect measurement is used, the measurement accuracy of the infrared thermal imager used in the experiment is within 2°C, which can meet the experimental requirements. Therefore, an infrared thermal imager is used to measure the temperature of the light-facing surface of the heat absorber.

8. How to provide power for the entire circulatory system. There are two ways to promote the flow of chloride salt in the system, one is to use inert gas to push, and the other is to use molten salt pump. If inert gas is used to push, on the one hand, the flow rate fluctuates greatly during the flow of chloride salt, and it is difficult to carry out research under certain working conditions; on the other hand, the pressure inside the salt storage tank is high, which increases the cost and operational risk. Therefore, the circulation system is powered by a molten salt pump.

9. How to realize the precise adjustment of the flow rate of chloride salt. The regulation of the flow rate in the experimental system can be achieved in two ways. One is to adjust the opening of the valve, and the other is to use a frequency conversion molten salt pump. Both methods need to install a flow meter behind the valve, and adjust the control through the feedback signal provided by the flow meter. If the method of adjusting the valve opening is adopted, since the melting point of chloride salt is as high as 380°C, if the valve opening is small, it is easy to solidify in the valve, which is not conducive to the safe operation of the system. Therefore, frequency conversion molten salt pumps are used.

See Figure 1 and Figure 2, a high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform, including a high-temperature chloride salt test system, energy storage system, electric heating system, heat preservation system, sunlight simulation system, and salt injection system , Salt discharge system, storage tank air isolation system and data acquisition and control system.

Among them, the high-temperature chloride salt test system is used to realize the flow of chloride salt during the experiment, including a first molten salt pump 26, a first salt storage tank 76, a chloride salt input channel 33, a first differential pressure detection channel 42, The heat sink 46 and the second differential pressure detection channel 55 . This experimental platform uses ternary chloride salt MgCl ₂ -KCl-NaCl (mole: 68.2-17.8-14%). When the temperature is lower than 380°C, the chloride salt is solid; when the temperature is higher than 380°C, the chloride The salt is liquid; the first salt storage tank 76 is equipped with a radar level gauge 25 for measuring the height of solid/liquid chloride salt. The bottom of the first salt storage tank 76 is equipped with a first salt storage tank support frame 69 for maintaining the balance of the tank body. Below the support frame 69 of the first salt storage tank, a resistance wire heating element 75 and an insulating material 74 are arranged to avoid excessive heat loss of the chlorinated salt in the heating process; Salt tank 77 to deal with emergencies such as molten salt leakage. The first molten salt pump 26 is installed and fixed on the top flange of the first salt storage tank 76, and the part of the first molten salt pump 26 conveying chloride salt goes deep into the inside of the first salt storage tank 76, so that the chloride salt is The first salt storage tank 76 is delivered to the chloride salt input channel 33 to provide power. By adjusting the motor frequency of the first molten salt pump 26 , the flow rate of the chloride salt in the chloride salt input channel 33 is controlled. The output end of the first molten salt pump 26 is connected to the chloride salt input channel 33 , and the chloride salt input channel 33 communicates the heat absorber 46 with the first salt storage tank 76 to deliver chloride salt for the operation of the heat absorber 46 . A solar simulator 73 is arranged on the facing surface of the heat absorber 46 for irradiation, and a number of N-type thermocouple wires 47 are arranged on the backlight surface, and the first N-type thermocouples for temperature measurement are installed at the inlet and outlet positions of the heat absorber 46 45 and the second N-type thermocouple 56. The chloride salt input channel 33 is connected to the first differential pressure detection channel 42 through a throttle member 43, and the first differential pressure detection channel 42 is combined with the throttle member 43 to measure the flow rate of chloride salt in the chloride salt input channel 33 It provides a feedback signal for adjusting the motor frequency of the first molten salt pump 26 . The chloride salt input channel 33 is connected to the second differential pressure detection channel 55 through the fourth three-way joint 44 and the fifth three-way joint 57 at the inlet and outlet positions of the heat absorber 46, and the second differential pressure detection channel 55 can be measured to obtain heat absorption The pressure difference between the inlet and outlet of the heat absorber is used to detect whether there is blockage or leakage of the chloride salt in the heat absorber.

The energy storage system is used to store the high-temperature molten salt flowing through the heat absorber 46 under the action of the solar simulator 73, and can be used as a high-temperature energy storage tank, and the high-temperature chloride salt is returned to the first salt storage tank in the next experiment , reduce the time to heat the chloride salt to the set temperature. It includes a second salt storage tank 81 , a second molten salt pump 59 , an intermediate heat exchanger 84 and a chloride salt return channel 78 . The input end of the second salt storage tank 81 is connected with the output end of the chloride salt input channel 33 , and the high-temperature molten salt after the action of the solar simulator 73 is transferred into the second salt storage tank 81 . The bottom of the second salt storage tank 81 is equipped with a second salt storage tank support frame 80 for maintaining the balance of the tank body. Below the support frame 80 of the second salt storage tank, an insulating material 74 and a resistance wire heating element 75 are arranged to reduce the heat loss of chlorinated salt during the heat preservation process, and to cope with the chlorination when the molten salt in the second salt storage tank 81 is transported. When the salt temperature is lower than the melting point; the second molten salt tank 79 is installed at the bottom of the second salt storage tank 81 to deal with emergencies such as molten salt leakage. The second molten salt pump 59 is installed and fixed on the top flange of the second salt storage tank 81, and the part of the second molten salt pump 59 conveying chloride salt goes deep into the inside of the second salt storage tank 81, so that the chloride salt is The second salt storage tank 81 is sent to the chloride salt return channel 78 to provide power. The output end of the second molten salt pump 59 is connected with the chloride salt return passage 78, and by adjusting the motor frequency of the second molten salt pump 59, the flow size of the chloride salt in the chloride salt return passage 78 is controlled, thereby adjusting The temperature of the inlet and outlet of the intermediate heat exchanger 84 and the amount of heat exchange through the intermediate heat exchanger 84 .

The electric heating system is used for the preheating and heat preservation of the chloride salt in the first salt storage tank 76, the second salt storage tank 81, and the salt injection tank 102, as well as the high temperature chloride salt test system, energy storage system, salt injection system and salt discharge System piping heat tracing. Concretely, it includes the resistance wire heating element 75 arranged on the periphery and bottom of the first salt storage tank 76, the second salt storage tank 81, and the salt injection tank 102, and is wound around the chloride salt input channel 33 and the chloride salt return channel. 78. The first differential pressure detection channel 42, the second differential pressure detection channel 55, the chloride salt return channel 30, the chloride salt discharge channel 71, the salt injection channel 92, the first argon purge channel branch 7, the second One argon purge channel, two branches 8, heat tracing equipment 11 for the pressure release section 14 of the heat absorber. The resistance wire heating element 75 is embedded in the insulation material 74 around the first salt storage tank 76 and the second salt storage tank 81, and the salt injection tank 102, and is connected with the first salt storage tank 76, the second salt storage tank 81, the salt injection tank The outer wall of the tank 102 is kept at a distance of 50 mm to avoid a short circuit during the heating process. Before the experiment starts, the resistance wire heating element and the heating equipment power are controlled by the data acquisition and control system, the chloride salt in the first salt storage tank 76 is heated to the set temperature and kept stable, and the pipeline is heated to the three-dimensional temperature. The melting point of the chloride salt MgCl ₂ -KCl-NaCl (mole: 68.2-17.8-14%) is above 50°C to prevent the chloride salt from solidifying when circulating in the pipeline. In the formal experiment, turn off the heating equipment to avoid the influence of the heating effect of the heating equipment on the reliability of the experimental results. After the experiment is over, start the heating equipment while turning on the salt discharge system to avoid the solidification of the chloride salt during the salt discharge process and blockage of the pipeline.

The thermal insulation system is used for thermal insulation of chlorinated salt during storage and pipeline transportation. , The mullite at the bottom of the second salt storage tank 81 is arranged in the chloride salt input passage 33, the chloride salt return passage 78, the first differential pressure detection passage 42, the second differential pressure detection passage 55, the chloride salt return passage Channel 30, chloride salt discharge channel 71, salt injection channel 92, first argon purge channel one branch 7, first argon purge channel two branch 8, silicic acid outside pressure release section 14 of heat absorber aluminum tube. The thermal insulation material 74 is alumina ceramic fiber. During the experiment, the thermal insulation material 74 arranged around the first salt storage tank 76 and the second salt storage tank 81 is used to reduce the heat dissipation of the molten salt in the tank, and cooperates with the resistance wire heating element 75 to maintain The stability of the molten salt temperature in the first salt storage tank 76 can also play the role of high-temperature energy storage in the second salt storage tank 81, so that high-temperature chloride salt can be kept at a high temperature for a long time in the second salt storage tank 81, shortening the next time. The time required to heat the chloride salt and reduce the power consumption; the insulation material arranged on the pipeline reduces the heat loss of the chloride salt in the pipeline, and avoids the solidification of the chloride salt during the flow process in the pipeline.

The sunlight simulation system is used to simulate the sun light source, and provides non-uniform radiation energy flow for the heat absorber 46, including a solar simulator 73, an energy flow meter 86, a camera 90, a water circulation pipeline 91, and a cooling water tank 88 connected through the water circulation pipeline 91 , electromagnetic flowmeter 89, feed water pump 87 and Lambertian target 72. The inlet end of the Lambertian target 72 is connected to the outlet end of the feed water pump 87 through the water circulation pipeline 91, the inlet end of the feed water pump 87 is connected to the outlet end of the cooling water tank 88 through the water circulation pipeline 91, and the inlet end of the cooling water tank 88 is connected to the electromagnetic pump 87 through the water circulation pipeline 91. The outlet end of the flowmeter 89 is connected, and the inlet end of the electromagnetic flowmeter 89 is connected with the outlet end of the Lambertian target 72 through the water circulation pipe 91, thereby forming a cooling water circulation in the solar simulation system. The fluence meter 86 is located at the center of the Lambertian target 72 , the solar simulator is facing the Lambertian target 72 , and the camera 90 is placed on one side of the solar simulator and facing the Lambertian target 72 . Before the experiment started, the solar simulator was tested for the concentrating characteristics to obtain a better concentrating spot. Place the energy flow meter 86 at the center of the Lambertian target 72 at the focal point of the solar simulator, turn on the feed water pump 87, so that the cooling water circulates in the water circulation pipeline 91 and the Lambertian target 72, and avoid the Lambertian target 72 being irradiated by the solar simulator 73 When the temperature is too high, it will be burnt. The electromagnetic flowmeter 89 is installed on the water circulation pipeline 91 between the cooling water tank 88 and the Lambertian target 72, and is used to monitor the cooling water flow rate and determine whether the cooling water is circulating. Further, the solar simulator 73 is turned on and adjusted so that a small focused energy flow spot is formed on the Lambertian target 72 , and the center of the focused energy flow is located at the fluence meter 86 . The camera 90 is used to photograph the light intensity distribution on the Lambertian target 72, and the Lambertian target 72 is moved so that the energy flow meter 86 is located at several test points successively. Combining the light intensity distribution captured by the camera 90 and the energy flow values at several test points, the energy flow density distribution and the total energy flow value on the Lambertian target 72 can be obtained. After the above operations are completed, the Lambertian target 72 is removed, and the heat absorber 46 is placed at the center of the Lambertian target 72, so that the solar simulator acts on the heat absorber 46 of the high-temperature chloride salt test system. According to the design solar simulation The device 73 provides radiant energy supply of 0-42kW. During the experiment, the power of the solar simulator is adjusted through the data acquisition and control system, and then the light-heat-mechanical coupling characteristics under different light intensities and different weather conditions are simulated.

The salt injection system is used to deliver the purified chloride salt to the first salt storage tank 76, including a salt injection port 85, a salt injection channel 92, a salt inlet 94, a salt outlet 95, a first gate valve 96, a steady Pressure channel 97, vacuum pump 98, second gate valve 99, fourth argon purge channel 100, fourth argon cylinder 101, salt injection tank 102, salt injection tank support frame 103, third molten salt tank 104. The fourth argon cylinder 101 is connected to the first end of the second gate valve 99 through the fourth argon purge channel 100 , and the second end of the second gate valve 99 is connected to the top cover plate of the salt injection tank 102 through the fourth argon purge channel 100 , The bottom of the salt injection tank 102 is equipped with a salt injection tank support frame 103 for maintaining the balance of the tank body. Below the salt injection tank support frame 103, a resistance wire heating element 75 and an insulating material 74 are arranged, which are used to heat the chloride salt before salt injection, and reduce the heat loss of the chloride salt in the heating process; the bottom of the salt injection tank 102 A third molten salt tank 104 is installed to deal with emergencies such as molten salt leakage. The vacuum pump 98 communicates with the salt injection tank 102 through a pressure-stabilizing channel 97 , and a first gate valve 96 is arranged on the pressure-stabilizing channel 97 . The vacuum pump 98 cooperates with the fourth argon cylinder 101 to ensure the argon environment in the salt injection tank during the delivery of the chloride salt. The salt inlet 94 is opened on the top cover plate of the salt injection tank 102, and is used to input purified chloride salt into the salt injection tank; the first end of the salt injection channel 92 is fixed on the top cover plate of the salt injection tank 102 The salt outlet 95 on the top goes deep into the tank body and is 50mm away from the bottom head, so that the chloride salt in the salt injection tank 102 can be transported to the first salt storage tank 76 as much as possible; the second salt injection channel 92 The end is connected with the salt injection port 85 fixed on the top cover plate of the first salt storage tank 76 to provide passages for the chloride salt to be transported from the salt injection tank 102 to the first salt storage tank 76. According to the design, when the chloride salt is transported from the salt injection tank 102 to the first salt storage tank 76, the fourth argon cylinder 101 delivers 0.03-0.05 MPa argon gas into the salt injection tank as power.

The salt discharge system is used to discharge the residual chloride salt in the pipeline and heat absorber after the experiment, and to discharge salt urgently in case of molten salt leakage. Specifically, it includes a first argon gas bottle 17, a first argon gas purging channel 5, a first tee joint 6, a branch 7 of the first argon gas purging channel, and a second branch 8 of the first argon gas purging channel. , the first two-way ball valve 9, the second two-way ball valve 10, the first three-way ball valve 12, the heat absorber pressure release section 14, the chloride salt return channel 30, the third three-way ball valve 32 and the chloride salt discharge channel 71 . The first argon gas bottle 17 is connected to the first end of the first argon gas purging channel 5, and the second end of the first argon gas purging channel 5 is connected to the first argon gas purging channel branch 7 through the first three-way joint 6 1. The first end of the second branch 8 of the first argon purging channel is connected, and the second end of the first argon purging channel 7 is connected to the first end of the heat absorber pressure release section 14 through the first three-way ball valve 12 Connected, wherein the pressure release section 14 of the heat absorber is located on the upper part of the heat absorber 46 . During the experiment, some gas may accumulate at the elbow of the heat absorber 46 during the flow of chloride salt, resulting in excessive local pressure and affecting the safe operation of the experimental platform. The second end of the pressure release section 14 of the heat absorber communicates with the upper part of the heat absorber 46, and this part of the gas can be introduced into the second salt storage tank 81 to reduce the risk of the experiment. The first two-way ball valve 9 is installed on the first argon purge passage 7, and the second two-way ball valve 10 is installed on the second argon purge passage 8, which is used to prevent the chloride salt from being blown by the heat absorber 46 during the experiment. The top reversely flows to the first salt storage tank 17, which is dangerous. The first end of the chloride salt return channel 30 is connected with the first salt storage tank 76, and the second end of the chloride salt return channel 30 is connected with the chloride salt input channel 33 through the third three-way joint 32, so that the heat absorber after the experiment ends The chlorinated salt on the left side of 46 all flows back in the first salt storage tank 76 . The chloride salt discharge passage 71 is connected with the lower end of the heat absorber 46, so that all the chloride salt at the lower end of the heat absorber 46 flows back in the second salt storage tank 81 after the end of the experiment. All chloride salt circulation pipes on the experimental platform are provided with an inclination angle of 3-5° to ensure that the chloride salt can flow back to the first salt storage tank 76 and the second salt storage tank 81 under the action of gravity after the experiment is over. In order to ensure the effect of salt removal, the first argon cylinder 17 will pass through the first argon purge channel 5, the first argon purge channel branch 7, the first argon purge channel two branch 8, the heat absorber Argon gas is introduced into the heat absorber 46 from the pressure release section 14; at the same time, in order to avoid the condensation of the chloride salt during the salt discharge process, the heating device 11 is turned on to assist the salt discharge during the salt discharge process. If the chlorinated salt leaks in the pipeline, the chlorinated salt is discharged into the first salt storage tank 76 and the second salt storage tank 81 according to the salt discharge operation at the end of the experiment; if the first salt storage tank 76, the second salt storage tank When the chloride salt in the salt storage tank 81 leaks, the fourth Y-type electric stop valve 68 and the sixth Y-type electric stop valve 82 are opened to discharge the chloride salt into the first molten salt tank 77 and the second molten salt tank 79 Inside.

The storage tank air isolation system is used to exhaust the air in the experimental platform to reduce the corrosion of chloride salt to the experimental equipment. Specifically, it includes a second argon gas cylinder 62, a second argon gas purging channel 19, a second tee joint 20, a second branch of the second argon gas purging channel 21, a first self-operated argon gas inlet valve 22, a second Two argon purge channels, one branch 24, the second self-operated argon inlet valve 15, the first electric ball valve 29, the first self-operated argon discharge valve 28, the first safety valve 27, the second safety valve 58, the first Two self-operated argon discharge valves 60, a second electric ball valve 61, a third argon cylinder 63, a third argon purge channel 64, a sixth tee joint 65, a branch 66 of the third argon purge channel and The third argon gas purges the second branch 67 of the channel.

The outlet end of the second argon gas cylinder 62 is directly connected to the first end of the second argon gas purging channel 19, and the second argon gas purging channel 19 is equipped with a first pressure sensor 18 for measuring the first self-operated argon gas entering The pre-valve pressure of valve 22. The second end of the second argon gas purging channel 19 is connected to the first end of the second argon gas purging channel branch 24 and the second argon gas purging channel two branches 21 through the second three-way joint 20, the second argon gas A second self-operated argon gas inlet valve 22 and a second pressure sensor 23 are arranged in sequence from the head end to the end of the gas purging channel branch 24, wherein the second pressure sensor 23 is used to measure the pressure of the first self-operated argon gas inlet valve. The pressure behind the valve of 22, that is, the pressure in the first salt storage tank 76; The second branch of the second argon purge channel 21 is arranged in sequence from the head end to the end with a second self-operated argon inlet valve 15 and a second pressure sensor 16, wherein the second pressure sensor 16 is used to measure the first self-operated argon gas The post-valve pressure entering the valve 15 is the pressure in the second salt storage tank 81 . The outlet end of the third argon cylinder 63 is directly connected to the first end of the third argon gas purging channel 64, and the second end of the third argon gas purging channel 64 is connected to the second argon gas purging channel through the sixth three-way joint 65. One branch 66 and the second branch 67 of the third argon purge channel are connected; the first electric ball valve 29 is installed on a branch of the pipeline connected to the top cover of the first salt storage tank, and the first self-operated argon discharge valve 28 Installed on another branch of the pipeline connected to the top cover of the first salt storage tank, the first safety valve 27 is installed on the top cover of the first salt storage tank, and the second self-operated argon discharge valve 60 is installed on the second On one branch of the pipeline connected to the top cover of the salt storage tank, the second electric ball valve 61 is installed on the other branch of the pipeline connected to the top cover of the second salt storage tank, wherein the second argon purge channel branch 66 The end is connected with the fourth Y-type electric shut-off valve 68 at the bottom of the first salt storage tank 76, and the end of the second branch of the second argon purge channel 67 is connected with the sixth Y-type electric shut-off valve 82 at the bottom of the second salt storage tank 81 connected.

Before the experiment, open the 3rd argon cylinder 63, the 4th Y type electric stop valve 68, the 6th Y type electric stop valve 82, the first electric ball valve 29, the second electric ball valve 61, to the first salt storage tank 76, Inject argon gas in the second salt storage tank 81, discharge the air in the tank body; Close the third argon cylinder 63, the fourth Y-type electric stop valve 68, the sixth Y-type electric stop valve 82, the first An electric ball valve 29 and a second electric ball valve 61 maintain the argon atmosphere in the salt storage tank. Remove the first branch 66 of the third argon purge channel and the second branch 67 of the third argon purge channel to avoid molten salt leakage in the experiment, and open the fourth Y-type electric stop valve 68 and the sixth Y-type electric stop valve 82 is affected to discharge salt in the first molten salt tank 77 and the second molten salt tank 79.

During the experiment, open the second argon gas bottle 62, the first self-operated argon gas inlet valve 22, the first self-operated argon gas discharge valve 29 can automatically adjust whether to open according to the pressure in the first salt storage tank 76, if the second The pressure in a salt storage tank 76 is less than 1kPa, then the first self-operated argon inlet valve 22 is automatically opened, the first self-operated argon discharge valve 29 is automatically closed, and the argon enters the first salt storage tank 76; When the pressure in the salt tank 76 is less than 1kPa, the first self-operated argon gas inlet valve 22 is automatically closed, the first self-operated argon gas discharge valve 29 is automatically opened, and the argon gas is discharged from the first salt storage tank 76 . The operations of the second self-operated argon gas inlet valve 15 and the second self-operated argon gas discharge valve 60 in the second salt storage tank 81 are the same as those of the first salt storage tank 76 . The above operations can maintain the stability of the pressure in the first salt storage tank 76 and the second salt storage tank 81 during the experiment. If the first self-operated argon inlet valve 22, the first self-operated argon discharge valve 29, the second self-operated argon inlet valve 15 or the second self-operated argon discharge valve 60 are damaged, the first salt storage tank 76, The pressure in the second salt storage tank 81 is higher than 100kPa or lower than -100kPa, then the first safety valve 27 and the second safety valve 58 are opened to prevent the pressure in the first salt storage tank 76 and the second salt storage tank 81 from being too high or Risk of being too low.

The data acquisition and control system is used for the acquisition of experimental data, the display of feedback control information on the experimental computer 4 and the control of equipment and instruments. Specifically, it includes the experimental power distribution cabinet 1, the experimental control cabinet 2, the data acquisition cabinet 3, the experimental computer 4, the radar level gauge 25, the first Y-type electric stop valve 13, and the second Y-type electric stop valve 31 , the third Y-type electric stop valve 34, the fourth Y-type electric stop valve 68, the fifth Y-type electric stop valve 70, the sixth Y-type electric stop valve 82, the throttling member 43, the first differential pressure sensor 38, the first Two differential pressure sensors 51, the first pressure sensor 18, the second pressure sensor 16, the third pressure sensor 23, the pressure transmitter 93, the first N-type thermocouple 45, the second N-type thermocouple 56, and the heat sink A number of N-type thermocouple wires 47 and an infrared camera 83.

The first Y-type electric shut-off valve 13 is installed on the pressure release section 14 of the heat absorber, the second Y-type electric shut-off valve 31 is installed on the chloride salt return channel 30, and the third Y-type electric shut-off valve 34 is installed on the chloride salt return channel 30. On the input channel 33, the fourth Y-type electric stop valve 68 is installed on the first molten salt tank 76, the fifth Y-type electric stop valve 70 is installed on the chloride salt discharge channel 71, and the sixth Y-type electric stop valve 82 is installed. On the second molten salt tank 81; wherein, the data acquisition cabinet 2 and the radar level gauge 25, the first differential pressure sensor 38, the second differential pressure sensor 51, the first pressure sensor 18, the second pressure sensor 16, the third Pressure sensor 23, resistance wire heating element, heat tracing equipment, first N-type thermocouple 45, second N-type thermocouple 56 and infrared thermal imager 83 are connected for real-time acquisition of temperature, flow and pressure drop during experimental operation , power, the first molten salt pump motor frequency, the second molten salt pump motor frequency and other data, and the data is transmitted to the computer 4 for the experiment, and the computer 4 for the experiment sends a control command to the first Y-type electric shut-off valve 13 , The second Y-type electric stop valve 31, the third Y-type electric stop valve 34, the fourth Y-type electric stop valve 68, the fifth Y-type electric stop valve 70, the sixth Y-type electric stop valve 82, resistance wire heating element 75. The first molten salt pump 26, the second molten salt pump 59, the solar simulator 73 and other equipment are controlled. The radar level gauge 25 is located on the top cover plate of the first salt storage tank 76, and monitors the liquid level height in the first salt storage tank 76 in real time to determine whether the liquid level height is too low, such as whether it is lower than the maximum level of the first molten salt pump 26. The height of the lower end; the experiment uses computer 4 to issue instructions to control the first Y-type electric stop valve 13, the second Y-type electric stop valve 31, the third Y-type electric stop valve 34, the fourth Y-type electric stop valve 68, and the fifth Y-type electric stop valve. Type electric shut-off valve 70, the opening and closing of the sixth Y-type electric shut-off valve 82. During the experiment, open the first Y-type electric stop valve 13, the third Y-type electric stop valve 34, close the second Y-type electric stop valve 31, the fourth Y-type electric stop valve 68, and the fifth Y-type electric stop valve 70 , the sixth Y-type electric stop valve 82; when discharging salt, open the second Y-type electric stop valve 31, the fifth Y-type electric stop valve 70, close the first Y-type electric stop valve 13, and the third Y-type electric stop valve 34. The fourth Y-type electric stop valve 68, the sixth Y-type electric stop valve 82; if the chloride salt leaks, open the second Y-type electric stop valve 31, the fourth Y-type electric stop valve 68, the fifth Y-type Type electric shut-off valve 70 and the sixth Y-type electric shut-off valve 82 discharge chloride salt into the first molten salt tank 77 and the second molten salt tank 79; the throttling member 43 is located on the chloride salt input channel 33, and the first A differential pressure sensor 38 is connected to both ends of the inlet and outlet of the throttling member 43 through the first differential pressure detection channel 42, and is used to measure the differential pressure at both ends of the throttling member 43, combined with the ternary chloride salt MgCl ₂ -KCl-NaCl (mole : 68.2-17.8-14%) parameters such as density, obtain the volume flow of chloride salt through conversion, in conjunction with volume flow, adjust the motor of the first molten salt pump 46 that is positioned at the first salt storage tank 76 top with computer 4 by experiment frequency, thereby adjusting the size of the volume flow; the second differential pressure sensor 51 is connected with the inlet port and the outlet port of the heat absorber 46 through the second differential pressure detection channel 55, and is used for real-time monitoring of the differential pressure value of the inlet and outlet of the heat absorber 46 . Among them, the second differential pressure detection channel 55 is also provided with a third high temperature diaphragm flange 48, a third cooling fin 49, a third medium and low temperature diaphragm flange 50, a fourth medium and low temperature diaphragm flange 52, a fourth cooling fin The sheet 53 and the fourth high-temperature diaphragm flange 54 are used to reduce the temperature of the medium in contact with the second differential pressure sensor 51 and prevent the high-temperature chloride salt from causing damage to the second differential pressure sensor 51; the first pressure sensor 18 is located at the first independent Type argon gas 22 enters the front end of the valve, which is used to monitor the pre-valve pressure of the first self-operated argon gas 22 in real time, prevent the pressure in the second argon gas cylinder 62 from being insufficient, and remind the timely replacement of the argon gas cylinder; the third pressure sensor 23 is located at The rear end of the first self-operated argon gas inlet valve 22 is used for real-time monitoring of the post-valve pressure of the first self-operated argon gas inlet valve 22 , that is, the pressure in the first salt storage tank 76 . When the measured pressure in the first salt storage tank 76 is lower than 1kPa, argon is injected into the tank; the second pressure sensor 16 is located at the rear end of the second self-operated argon inlet valve 15 for real-time monitoring of the second self-operated The post-valve pressure of the argon entering the valve 22 is the pressure in the second salt storage tank 81. When the measured pressure in the second salt storage tank 81 is lower than 1kPa, argon is injected into the second salt storage tank 81; The pressure value in the salt tank; the first N-type thermocouple 45 and the second N-type thermocouple 56 are respectively located at the inlet side and the outlet side of the heat absorber 46, and the temperature values at the corresponding positions are obtained in real time. Combining this result with the specific heat, density and other thermophysical parameters of the ternary chloride salt MgCl ₂ -KCl-NaCl (mole: 68.2-17.8-14%), the chloride salt can be obtained when it flows through the heat absorber 46 The amount of heat absorbed, and then combined with the total energy flow value to calculate the thermal efficiency; some N-type thermocouple wires 47 on the heat absorber 46 are located on the backlight surface of the heat absorber 46, and are used to obtain the real-time temperature distribution on the backlight surface of the heat absorber 46; The thermal imaging camera 83 is on one side of the solar simulator 73 and faces the light-facing surface of the heat absorber 46 , and is used to obtain the real-time temperature distribution of the light-facing surface of the heat absorber 46 . The thermal stress of the heat absorber 46 is calculated in combination with the real-time temperature distribution of the light-facing surface and the back-light surface of the heat absorber, or the thermal-mechanical coupling and failure mechanism of the heat absorber 46 are further studied.

In this experiment, a solar simulator is used to simulate the focused non-uniform energy flow distribution, which provides energy for the heat absorption process of the ternary chloride salt MgCl ₂ -KCl-NaCl (mole: 68.2-17.8-14%) in the heat absorber. Adjust the operating conditions to maximize the temperature of the chloride salt at the outlet of the heat absorber. The operation method of this experimental platform is given below, and the specific steps are as follows:

Step 1. Before entering the laboratory, wear work clothes, safety helmets, gloves, gas masks and other protective equipment; after entering the laboratory, first open the doors and windows, and start the laboratory exhaust system to ensure that the laboratory is well ventilated; check Whether there are flammable and explosive materials around the experimental platform, if found, clean up immediately; check whether the fire extinguisher is placed in the correct position, and check its performance. After all the above are confirmed to be correct, turn on the power supply of the experimental power distribution cabinet 1;

Step 2, place the energy flow meter 86 at the center of the Lambertian target 72 at the focus position of the solar simulator 73; open the cooling water tank 88 and the feed water pump 87, so that the cooling water flows in the water circulation pipeline 91, and the Lambertian target 72 is supplied by the cooling water And power flow meter 86 cooling. Plot the position coordinates of the points to be tested on the Lambertian target 72 . Turn on the fan of the solar simulator control box, turn on and debug the solar simulator 73, so that a smaller focused energy flow spot is formed on the Lambertian target 72, and the size of the spot is between the height of the heat absorber 46 and the length of the heat absorber 46 , and the center of the focused energy flow is located at the energy flow meter 86 . A camera 90 is used to take pictures of the light intensity distribution of the Lambertian target 72 and record the energy flow value measured by the energy flow meter 86 . Turn off the solar simulator 73, move the Lambertian target 72, so that the fluence meter 86 is located at the spatial coordinates of each test point in turn. Turn on the solar simulator 73 , use the camera 90 to take pictures of the light intensity distribution of the Lambertian target 72 , and record the energy flow value measured by the energy flow meter 86 . Import the photos of the light intensity distribution into the Adobe Photoshop of the experimental computer 4 for processing to obtain the light intensity information (ie gray value) of each test point position, and bring the energy flow value and gray value of each test point between the two The functional relational expression of is solved to obtain the coefficients in the functional relational expression. Then bring the light intensity at different positions of the Lambertian target 72 into the functional relationship between the energy flow value and the gray value, and obtain the energy flow values at different positions of the Lambertian target 72 to obtain the light concentration characteristics of the solar simulator .

Among them, the functional relationship between the energy flow value and the gray value is: I _x =I _b +k·G _x , I _x is the radiation energy flow value, the unit is kW/m ² , and it is obtained through the measurement of the energy flow meter; I _b is the radiation energy flow constant, the unit is kW·m ^-2 ; k is the conversion coefficient, the unit is kW·m ^-2 ; G _x is the gray value;

Close the solar simulator 73, close the blower fan of the solar simulator control box, the cooling water tank 88 and the feedwater pump 87 after 2min;

Step 3. Remove the Lambertian target 72 and place the heat absorber 46 at the focus position of the solar simulator 73 . Close the first Y-type electric stop valve 13, the second Y-type electric stop valve 31, the third Y-type electric stop valve 34, the fifth Y-type electric stop valve 70, the first two-way ball valve 9, and the second two-way ball valve 10 , open the first electric ball valve 29, the second electric ball valve 61, the fourth Y-type electric stop valve 68, the sixth Y-type electric stop valve 82, adjust the first three-way ball valve 12 so that it points to the first two-way ball valve 9, The salt injection port 85 is sealed with a blind flange to keep the first argon cylinder 17 and the second argon cylinder 62 closed so that a relatively sealed environment is formed in the first salt storage tank 76 and the second salt storage tank 81 . Open the third argon cylinder 63, and the argon enters the first salt storage tank through the fourth Y-type electric shut-off valve 68 and the sixth Y-type electric shut-off valve 82 at the bottom of the first salt storage tank 76 and the second salt storage tank 81 respectively 76 and the second salt storage tank 81, the air in the first salt storage tank 76 and the second salt storage tank 81 is purged. Since the density of argon is much greater than that of air, argon will be deposited at the bottom of the tank. As the argon gas introduced gradually increases, the air will be discharged out of the tank by the first electric ball valve 29 and the second electric ball valve 61 . After the above operation continued for 5-6 minutes, the air in the first salt storage tank 76 and the second salt storage tank 81 has been completely discharged. Close the third argon cylinder 63, the first electric ball valve 29, the second electric ball valve 61, the fourth Y-type electric stop valve 68, and the sixth Y-type electric stop valve 82, and remove a branch of the third argon purge channel 66. The second branch 67 of the third argon gas purging channel.

Step 4: Seal the salt inlet 94 and the second end of the salt injection channel 92 with a blind flange, and open the first gate valve 96 and the second gate valve 99 . Turn on the vacuum pump 98, evacuate the salt injection tank 102, and close the vacuum pump 98; open the fourth argon cylinder 101, pour argon into the salt injection tank 102, so that the pressure in the salt injection tank is 1 atmosphere, and close the fourth argon gas bottle 101. Gas cylinder 101; open vacuum pump 98 here, vacuumize salt injection tank 102, close and close vacuum pump 98; open the fourth argon gas cylinder 101, rush into argon gas in salt injection tank 102, so that the pressure in the salt injection tank is 1 Atmospheric pressure, close the fourth argon cylinder 101. Repeat this for 5 to 8 times, it is considered that the air in the salt injection tank 102 has been completely discharged; open the flange blind plate of the salt inlet 94, and inject the purified chloride salt into the salt injection tank 102 through the salt inlet 94 , close the blind flange at the salt inlet 94; open the blind flange at the second end of the salt injection port 85 and the salt injection channel 92, and connect the second end of the salt injection channel 92 with the salt injection port 85, open The fourth argon cylinder 101, injecting 0.03-0.05MPa argon into the salt injection tank, injecting chloride salt into the first salt storage tank 76, closing the salt injection port 85 and the second end of the salt injection channel 92 Blue blind plate, open the second argon cylinder 62, keep the first salt storage tank 76 and the second salt storage tank 81 full of argon, and isolate the air;

Step 5. Open the first Y-type electric stop valve 13 and the third Y-type electric stop valve 34 , and adjust the first three-way ball valve 12 to point to the first Y-type electric stop valve 13 . Start the resistance wire heating element 75 to provide heat for the chloride salt in the first salt storage tank 76 . In the heating process, the method of "variable power adjustment, step-by-step heating" is adopted to heat the chloride salt to the target temperature; at the same time, the heat tracing equipment is started, and the heating temperature of the pipeline is set to 430°C (higher than the ternary chloride salt MgCl _2- KCl-NaCl (mole: 68.2-17.8-14%) melting point 50°C). After the temperature of the chloride salt and the pipeline reaches the set temperature and remains stable for 10 to 15 minutes, the solar simulator 73 is started, and the sun-facing surface of the heat absorber 46 will receive the radiation of the solar simulator 73 . Turn on the thermal imaging camera 83 to monitor the surface temperature distribution of the heat absorber 46 . When the temperature of the outer wall surface of the pipeline of the heat absorber 46 reaches the set value, the first molten salt pump 26 is opened to deliver the chloride salt, and the flow value of the chloride salt is monitored in real time by the computer 4 for the experiment, and is automatically adjusted according to the size of the flow value The motor frequency of the first molten salt pump 26 makes the chloride salt flow rate reach the set value. During the experiment, the liquid level value measured by the radar level gauge 25 was monitored in real time to prevent the chloride salt liquid level from falling below the lower end of the first molten salt pump 26, causing the first molten salt pump 26 to run idly and affecting equipment performance.

Step 6. After the test platform has been running for a period of time, observe the first N-type thermocouple 45, the second N-type thermocouple 56, the infrared thermal imager 83, some N-type thermocouple wires 47 on the backlight surface of the heat absorber, and the first differential thermocouple. The indications of the pressure sensor 38, the second differential pressure sensor 51, the radar level gauge 25, the N-type thermocouple in the first salt storage tank, and the N-type thermocouple in the second salt storage tank, wait after the above-mentioned indications are stable. 5 to 10 minutes, if there is no change, it is considered that the entire experimental platform is in a state of thermal equilibrium. Start to record the temperature of chloride salt at the inlet and outlet of the heat absorber, the temperature distribution of the sun-facing surface of the heat absorber, the temperature distribution of the back-light surface of the heat absorber, the volume flow rate of chloride salt, the pressure difference between the inlet and outlet of the heat absorber, the first The liquid level height in a salt storage tank, the chloride salt temperature in the first salt storage tank 76 and the chloride salt temperature in the second salt storage tank 81, the light intensity information (gray Degree value), the above data is recorded every 5 seconds, and the entire recording time is controlled within 30 to 60 minutes. During the experiment, pay special attention to the volume flow obtained by converting the differential pressure value measured by the first differential pressure sensor 38, and the differential pressure value at both ends of the heat absorber measured by the second differential pressure sensor 51. If the measured volume flow value is abnormal If the differential pressure value at both ends of the heat absorber decreases abnormally, it means that there is a blockage in the pipeline or the heat absorber 46; leakage. If the above situation occurs, there will be an alarm signal to remind on the experiment computer 4 . At this time, the power supply of the first molten salt pump 26 is cut off by the computer 4 for the experiment, the heat tracing equipment 11 is opened, the third Y-type electric stop valve 34 is closed, the second Y-type electric stop valve 31 is opened, and the fifth Y-type electric stop valve is opened. The valve 70 makes the chloride salt flow back into the first salt storage tank 76 and the second salt storage tank 81 along the chloride salt return passage, the chloride salt input passage, and the chloride salt discharge passage respectively. Manually adjust the first three-way ball valve 12 so that it points to the first two-way ball valve 9, manually open the first two-way ball valve 9 and the second two-way ball valve 10, and manually open the first argon cylinder to assist in salt discharge;

Step 7. Chloride salt temperature at the inlet and outlet of the heat absorber, temperature distribution of the heat absorber facing the sun, temperature distribution of the backlight surface of the heat absorber, volume flow rate of chloride salt, pressure difference between the inlet and outlet of the heat absorber After all data collection is completed, the power supply of the first molten salt pump 26 is disconnected through the computer 4 for the experiment, and the heat tracing equipment 11 is turned on, the third Y-type electric shut-off valve 34 is closed, the second Y-type electric shut-off valve 31, the second Y-type electric shut-off valve are opened. Five Y-type electric cut-off valves 70 make the chloride salt in the heat absorber 46 flow back to the first salt storage tank 76 and the second storage tank respectively along the chloride salt return passage, the chloride salt input passage, and the chloride salt discharge passage. Inside the salt tank 81. Manually adjust the first three-way ball valve 12 to point to the first two-way ball valve 9, manually open the first two-way ball valve 9 and the second two-way ball valve 10, and manually open the first argon cylinder to purge the argon gas into the pipeline Drain the salt. Observe the indications of the radar level gauge 25 installed on the top of the first salt storage tank 76, when the liquid level value no longer changes, wait for 5 to 10 minutes, and think that the salt discharge process has been basically completed. Turn off the power supply of solar simulator 73, heat tracing equipment 11, resistance wire heating element 75 by experiment computer 4, manually close the first argon cylinder 17, the first two-way ball valve 9, the second two-way ball valve 10, adjust the first Three-way ball valve 12 makes it point to the first Y-type electric shut-off valve 13, closes the first Y-type electric shut-off valve 13, the second Y-type electric shut-off valve 31, the fifth Y-type electric shut-off valve 70 by the experiment computer 4;

Step 8, ventilating and cooling the experimental site, disconnecting the power supply of the experimental power distribution cabinet;

Step 9, before the next experiment, monitor the chloride salt temperature in the first salt storage tank 76 and the second salt storage tank 81, if the chloride salt temperature in the first salt storage tank 76 is above the melting point and the second salt storage tank The temperature of the chloride salt in the tank 81 is higher than the melting point by 50°C, and the second molten salt pump 59 is turned on to transport the high-temperature chloride salt in the second salt storage tank 81 to the first salt storage tank 76; otherwise, the resistance wire is turned on The heating element is used to heat the temperature of the chloride salt in the first salt storage tank 76 above the melting point, and when the temperature of the chloride salt in the second salt storage tank 81 is 50°C higher than the melting point, the second molten salt is turned on The pump 59 transports the chloride salt in the second salt storage tank 81 to the first salt storage tank 76 . It should be noted that during the transportation of molten salt, the indication of the radar level gauge 25 located at the top of the first salt storage tank 76 needs to be monitored in real time, and according to the liquid level height of the first salt storage tank 76 and the total chloride salt Calculate the liquid level in the second salt storage tank. Prevent the chloride salt height in the second salt storage tank from falling below the lower end of the second molten salt pump 59; during the operation of the actual tower-type power station, it is determined when the second salt storage tank will be closed according to the electricity demand. The high-temperature chloride salt is exported to the first salt storage tank. In the process of exporting the chloride salt, the heat exchange between the high-temperature chloride salt and supercritical carbon dioxide will be realized through the action of the intermediate heat exchanger, and the temperature of the inlet and outlet of the intermediate heat exchanger 84 will be recorded. , and according to the liquid level height of the first salt storage tank 76 of record, calculate the heat that supercritical carbon dioxide obtains through the intermediate heat exchanger; heat loss;

Step 10. According to the recorded light intensity information (gray value) on the light-facing surface of the heat absorber, and the functional relationship between the energy flow value and the gray value obtained in step 2, the energy of the light-facing surface of the heat absorber is obtained. flow distribution. Calculate the incident radiant energy provided by the solar simulator 73 to the heat absorber 46 according to the energy flow distribution on the face of the heat absorber; The heat absorbed by the salt when it flows in the heat absorber. Combined with the incident radiant energy, calculate the heat loss and thermal efficiency of the heat absorber; calculate the second salt storage tank according to the liquid level in the first salt storage tank recorded in step 6 and the chloride salt temperature of the second salt storage tank 81 Stored energy; import the recorded temperature distribution on the light-facing surface of the heat absorber and the temperature distribution on the back-light surface of the heat absorber into the commercial software ANSYS Mechanical to analyze the thermal stress of the heat absorber;

Step 11. To analyze the influence of unsteady and non-uniform heat flow on the temperature distribution of the outer wall of the heat absorber, firstly, based on steps 1 to 10, obtain the flow rate of chloride salt under different light intensities when the outlet temperature of the heat absorber remains constant. value. On this basis, the experiment time is stipulated, and the power of the solar simulator is grouped. For example, the power of the solar simulator is divided into 7 groups, the power of each group is 0, 7kW, 14kW, 21kW, 28kW, 35kW, 42kW, the experiment time is set to 20 minutes, the power of the solar simulator in the first 8 minutes It is set to 42kW, and the flow through the heat absorber is set to the flow value corresponding to 42kW in the steady state calculation. From the 9th to 20th minutes, the power of the solar simulator decreases step by step, and the flow rate is set to the flow value corresponding to each power in the steady state calculation. The working time of the solar simulator is 2 minutes under each power. The infrared thermal imaging camera records the temperature distribution of the light-facing surface of the heat absorber every 5 seconds, and the N-type thermocouple wire on the backlight surface of the heat absorber records the temperature distribution of the backlight surface of the heat absorber every 5 seconds. The influence of unsteady and non-uniform heat flow on the temperature distribution of the outer wall of the heat absorber can be obtained by analyzing the temperature distribution of the heat absorber on the light-facing surface and the back-light surface during the whole experiment;

To explore the dynamic performance prediction method of the heat absorber outlet temperature, firstly, based on steps 1 to 10, the flow values of chloride salts under different light intensities are obtained when the heat absorber outlet temperature remains constant. Then, according to steps 1 to 6, the outlet temperature of the heat absorber when the experimental system is running stably under a certain solar simulator power condition is obtained, the power of the solar simulator is changed, and the flow rate of the chloride salt is adjusted to the steady-state calculation. The flow value corresponding to the power, record the time required from changing the power of the solar simulator to the temperature stabilization of the heat absorber outlet, and compare this time with the calculation results of the numerical model to verify the proposed predicted dynamic performance of the heat absorber outlet temperature reliability of the numerical model.

In step 9, calculate the heat that supercritical carbon dioxide obtains through intermediate heat exchanger, comprise the following steps:

SA1, based on the liquid level height h ₁ in the first salt storage tank obtained in step 6, combined with the initial chloride salt volume V ₀ in the first salt storage tank, the radius R ₁ of the first salt storage tank, and the The volume of chloride salt V ₁ is calculated as the volume of chloride salt in the second salt storage tank, expressed as: V ₂ =V ₀ -V ₁ -π·R ₁ ² ·h ₁ ;

SA2. Based on the temperatures T ₁ and T ₂ at the inlet and outlet of the intermediate heat exchanger obtained in step 9, calculate the constant volume specific heat capacities c ₁ and c ₂ of the chloride salt at corresponding temperatures. Furthermore, the heat available for supercritical carbon dioxide is obtained, expressed as: Q ₀ =ρV ₂ (c ₂ ·T ₂ -c ₁ ·T ₁ ).

In step 9, calculating the heat loss of the second salt storage tank includes the following steps:

SB1, based on the salt chloride temperature T ₃ of the second salt storage tank obtained in step 6, combined with the salt chloride temperature T ₄ of the second salt storage tank obtained in step 9, and the temperature in the second salt storage tank obtained in step SA1 Calculate the volume V ₂ of chloride salt, and calculate the constant volume specific heat capacity c ₃ and c ₄ of chloride salt at the corresponding temperature. The heat loss of the second salt storage tank is obtained, expressed as: Q ₁ =ρV ₂ (c ₃ ·T ₃ −c ₄ ·T ₄ ).

In step 10, the overall process of calculating the heat loss and thermal efficiency of the heat sink includes the following steps:

SC1. Bring the gray value of each point on the light-facing surface of the heat absorber into the functional relationship between the energy flow value and the gray value obtained in step 2, and calculate the energy of each point on the light-facing surface of the heat absorber. Flow value, to obtain the energy flow distribution of the entire heat absorber facing the sun;

Q_t即为太阳能模拟器投射到吸热器迎光面的总能流值，也即入射辐射能；I_j为单个测试点的能流值；A_j为单个测试点所占的面积；SC2. Calculation of incident radiant energy: the formula for calculating the total energy flow value of the heat absorber facing the light:

_Qt is the total energy flow value projected by the solar simulator to the light-facing surface of the heat absorber, that is, the incident radiant energy; I _j is the energy flow value of a single test point; A _j is the area occupied by a single test point;

SC3. Based on the chloride salt temperatures T _in and T _out at the inlet and outlet of the heat absorber obtained in step 6, calculate and obtain the constant pressure specific heat capacities c _p,in and c _p,out of the chloride salt at corresponding temperatures. Read the measured value of the throttling piece and the first differential pressure sensor, and obtain the volume flow rate of chloride salt through conversion, and obtain the corresponding mass flow rate q _m of chloride salt after conversion, and then obtain the flow rate of chloride salt flowing through the heat absorber. The heat Q _x absorbed at the time of the calculation is: Q _x ＝q _m (c _p,out T _out -c _p,in T _in );

SC4. Calculate the heat loss Q _loss of the heat absorber, the calculation formula is: Q _loss = Q _t - Q _x ;

SC5. Calculate the thermal efficiency η of the heat absorber, the calculation formula is: η=Q _x /Q _t ×100%.

In step 9, the energy stored in the second salt storage tank is calculated, including the following steps:

SD1, based on the chloride salt temperature _T5 in the second salt storage tank 81 obtained in step 6, calculate the constant volume specific heat capacity _c5 and _c6 of the chloride salt at _T5 and normal temperature _T6 , combined with the temperature T5 obtained based on step SA1 The chloride salt volume V ₂ in the second salt storage tank is obtained to obtain the energy stored in the second salt storage tank, expressed as: Q ₀ =ρV ₂ (c ₅ ·T ₅ −c ₆ ·T ₆ ).

FIG. 4 shows the structure of the heat absorber 46 in the experimental platform and a schematic diagram of several N-type thermocouple wires 47 on the backlight surface of the heat absorber. The structure of the heat absorber is designed as a circuitous coil. On each vertical heat absorbing tube, no less than 3 N-type thermocouples are arranged in the horizontal direction, and no less than 9 N-type thermocouples are arranged in the vertical direction. Considering that only one side of the heat sink 46 can be heated by the solar simulator 73 in the laboratory, this design increases the heating area while saving space.

This experimental platform uses a solar simulator to apply the non-uniform energy flow acting on the heat absorber to verify the reliability of the operation of the experimental system when the operating temperature of chloride salt is 565-700°C, and to carry out heat absorber under different light intensities and operating conditions The coupling mechanism of light and heat and the corrosion performance of chloride salts on different metals, study the type of molten salt, heat absorber material, heat absorber coating, heat absorber structure, heat absorption tube strengthening structure, etc. The influence of the performance of the energy storage system and the thermal stress failure mechanism of the heat absorber under the condition of extreme non-uniform energy flow, the influence of unsteady and non-uniform energy flow on the temperature distribution of the outer wall of the heat absorber, and the dynamic performance of the outlet temperature of the heat absorber method of prediction. This experimental platform can be used to carry out the cycle simulation experiment of the tower absorber under the condition of focused non-uniform energy flow.

Compared with the existing solar energy simulation experiment platform, the present invention is characterized in that: (1) The solar cycle simulation experiment with the outlet temperature of the heat absorber as high as 565-700°C is carried out, and the working medium and metal materials used in the existing solar power stations are all It has been severely challenged, but it can achieve higher photothermal efficiency and reduce costs. In terms of working medium, it is better to choose thermally stable chloride salt, but it is highly corrosive at high temperature. Combined with the corrosion mechanism of chloride salt, the air isolation system of the storage tank is designed to reduce the corrosion performance of chloride salt; in terms of metal materials, for the first salt storage tank, the second salt storage tank, For components such as chloride salt input channel, chloride salt return channel, chloride salt discharge channel, first differential pressure detection channel, and second differential pressure detection channel, Haynes 230 with excellent high temperature resistance and corrosion resistance is selected to ensure (2) The high-temperature working environment of this experimental platform poses challenges to the use of liquid level, flow and differential pressure measurement equipment. For this reason, microwave-permeable high-temperature-resistant quartz glass is installed under the radar probe of the radar level gauge as a temperature insulation device; high-temperature diaphragm flanges, medium and low temperature Diaphragm flanges, cooling fins, etc., reduce the temperature of the working medium in direct contact with the differential pressure sensor; (3) In order to prevent the chlorinated salt from solidifying and blocking the pipeline when flowing in the pipeline, heat tracing equipment, pipeline insulation materials, Pipeline slope, argon purging to assist salt discharge, etc., and design chloride salt return channels, chloride salt discharge channels, etc. during salt discharge, to minimize the possibility of chloride salt solidification; (4) design The second salt storage tank is used as a high-temperature energy storage tank to store the high-temperature chloride salt after being irradiated by the solar simulator, and transport the high-temperature chloride salt to the first salt storage tank before the second experiment, reducing the second The heating time of the chlorinated salt in the salt storage tank is reduced and the power consumption is reduced. During the operation of the actual tower power station, through the heat exchange between the intermediate heat exchanger and the supercritical carbon dioxide, the supercritical carbon dioxide heated to a specific parameter will drive the turbine to do work and drive the generator to generate electricity; (5) use a resistance furnace as a salt storage The heating system of the tank adopts the method of "variable power adjustment, step-by-step heating". On the basis of ensuring the heating effect, it avoids the direct contact between the resistance wire heating element and the high-temperature chloride salt, and reduces the corrosiveness of the chloride salt. (6) The combination of the first molten salt pump and the differential pressure flowmeter to control the flow of chloride salt ensures the stable and efficient operation of the experiment; (7) An infrared thermal imager is designed to indirectly measure the incoming heat of the heat absorber. The method of surface temperature avoids the use of N-type thermocouple wires to measure the shading effect on the radiation and light of the solar simulator and the possible risk of burning; (8) The data acquisition and control system is designed to realize the remote operation of the experimental platform. On the basis of ensuring the experimental effect, the safety of the experimental process is guaranteed; (9) the use of the solar simulation system is more suitable for the actual concentrated solar radiation, and it is not affected by environmental factors such as weather changes, and can carry out different experiments stably indoors. Experimental research on light intensity, light-thermal-mechanical coupling mechanism of heat absorber under different working conditions, etc.

The implementation method given above is the basic idea for realizing the present invention, and the implementation details of the present invention are not limited to the above-mentioned process. Any non-essential additions and substitutions made by those skilled in the art based on the technical features of the present invention belong to the protection scope of the present invention.

Claims (8)

1. A high temperature chloride salt photothermal and energy storage cycle simulation experiment platform, characterized in that it includes a high temperature chloride salt test system, an energy storage system, an electric heating system and a sunlight simulation system; The high-temperature chloride salt test system includes a first salt storage tank (76), a first molten salt pump (26) and a chloride salt input channel (33), and the first salt storage tank (76) is equipped with a second A molten salt pump (26), the input end of the first molten salt pump (26) extends into the first salt storage tank (76), and the output end is connected to the first end of the chloride salt input channel (33). The second end of the salt input channel (33) is connected to the second salt storage tank (81), and a heat absorber (46) is installed on the chloride salt input channel (33); The energy storage system includes a second salt storage tank (81), a second molten salt pump 59, and a chloride salt return channel 78, and an intermediate heat exchanger (84) is installed on the chloride salt return channel (78) , for heat exchange between the high-temperature chloride salt from the second salt storage tank (81) and supercritical carbon dioxide; the second salt storage tank (81) is equipped with a second molten salt pump (59), the The input end of the second molten salt pump (59) extends into the second salt storage tank (81), and the output end is connected to the first end of the chloride salt return channel (78). The two ends are connected with the inlet of the first salt storage tank (76); A throttling piece (43) and a first differential pressure sensor (38) are installed on the chloride salt input channel (33), and the first differential pressure sensor (38) communicates with the throttle through the first differential pressure detection channel (42) Both ends of the inlet and outlet of the piece (43) are connected to measure the differential pressure at both ends of the throttling piece (43); The electric heating system includes a heating element (75) arranged outside the first salt storage tank (76) and the second salt storage tank (81), and a chloride salt input channel (33), a chloride salt input channel Heat tracing equipment (11) outside the channel (78); The sunlight simulation system includes a solar simulator (73), a dynamometer (86), a camera (89) and a Lambertian target (72), and the dynamometer (86) is located at the center of the Lambertian target (72), The solar simulator is facing the Lambertian target (72), and the camera (89) is placed on the side of the solar simulator and faces the Lambertian target (72); the Lambertian target (72) and the solar simulator (73) are both arranged on the heat absorber (46) front, the camera (89) is used to take photos of the light intensity distribution on the Lambertian target (72); The first differential pressure detection channel (42) is sequentially provided with a first high temperature diaphragm flange (35), a first cooling fin (36), a first medium and low temperature diaphragm flange (37), a first differential pressure sensor (38), the second medium and low temperature diaphragm flange (39), the second cooling fin (40) and the second high temperature diaphragm flange (41); A radar level gauge (25) is installed on the first salt storage tank (76), and the radar level gauge (25) is used to measure the height of solid/liquid chloride salt; the radar level gauge (25 ) under the radar probe is installed microwave-permeable high-temperature-resistant quartz glass. 2. A high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform according to claim 1, characterized in that the first salt storage tank (76) and the chloride salt return channel (30) are first The second end of the chloride salt return channel (30) is connected to the first end of the chloride salt input channel (33), and the upper part of the heat absorber (46) is provided with a heat absorber pressure release section (14) , the pressure release section (14) of the heat absorber passes through the first argon purge channel branch (7) and the first argon purge channel two branches (8) and the first argon purge channel (5 ), the gas inlet of the first argon purge channel (5) is connected to the first argon cylinder (17); the lower end of the heat absorber (46) is connected to the second Salt storage tank (81) connection. 3. A high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform according to claim 2, characterized in that the first salt storage tank (76) and the second salt storage tank (81) are surrounded by Covered with thermal insulation material (74), the chloride salt input channel (33), the chloride salt return channel (78), the chloride salt return channel (30), and the chloride salt discharge channel (71) are provided with silicon Acid aluminum tube. 4. A high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform according to claim 2, characterized in that the first salt storage tank (76), the second salt storage tank (81), the chloride salt The input channel (33), the chloride salt return channel (78), the chloride salt return channel (30) and the chloride salt discharge channel (71) are made of Haynes230 alloy material. 5. A high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform according to claim 1, characterized in that it also includes a storage tank air isolation system, and the storage tank air isolation system includes a second argon gas cylinder (62) and a third argon cylinder (63); The outlet end of the second argon gas cylinder (62) is connected to the first end of the second argon gas purging channel (19), and the second end of the second argon gas purging channel (19) passes through the second tee joint (20) It is connected with the first end of the first branch of the second argon gas purging channel (24) and the second branch of the second argon gas purging channel (21); the end of the second branch of the second argon gas purging channel (24) is connected with the first The inlet end of a salt storage tank (76) is connected; The outlet end of the third argon gas bottle (63) is directly connected to the first end of the third argon gas purging channel (64), and the second end of the third argon gas purging channel (64) passes through the sixth three-way joint ( 65) It is connected with the first branch of the third argon gas purging channel (66) and the second branch of the third argon gas purging channel (67). 6. A high-temperature chloride salt photothermal and energy storage cycle simulation experiment platform according to claim 1, characterized in that a salt injection port (85) is opened on the first salt storage tank (76), and the The salt injection port (85) communicates with the salt injection tank (102) through the salt injection channel (92), and the salt injection tank (102) communicates with the fourth argon cylinder (101) through the fourth argon purging channel (100) ), the salt injection tank (102) is connected to the first end of the pressure stabilization channel (97), and the second end of the pressure stabilization channel (97) is connected to the outlet of the vacuum pump (98); the salt injection tank (102 ) The top cover plate is provided with a salt inlet (94). 7. The high-temperature chloride salt photothermal and energy storage cycle experimental method based on the experimental platform of claim 1, characterized in that it comprises the following steps: Step 1. Place the energy flow meter (86) at the focal point of the solar simulator (73), and cool down the Lambertian target (72) and the energy flow meter (86); draw the position of the test point on the Lambertian target (72) Coordinates, start and debug the solar simulator (73), so that the focused energy flow spot formed on the Lambertian target (72), the center of the focused energy flow is located at the energy flow meter (86); photograph the Lambertian target (72) light intensity distribution photos, and record the energy flow value measured by the energy flow meter (86); Turn off the solar simulator (73), move the Lambertian target (72), enable the flow meter (86) to be located at the spatial coordinates of each test point in turn, turn on the solar simulator (73), and take pictures of the light intensity distribution of the Lambertian target (72). photo, and record the energy flow value measured by the energy flow meter (86); Bring the energy flow value and gray value of each test point into the functional relationship between the two, and the coefficients in the functional relationship can be obtained by solving; Step 2. Remove the Lambertian target (72), place the heat absorber (46) at the focal position of the solar simulator (73), place the first salt storage tank (76) and the second salt storage tank (81) The air is discharged, and the ternary chloride salt MgCl ₂ -KCl-NaCl is injected into the first salt storage tank (76) for standby, and the first salt storage tank (76) and the second salt storage tank (81) are kept full of argon state, isolated from air; Step 3. Heat the chloride salt in the first salt storage tank (76) to the target temperature by heating step by step; at the same time, heat the chloride salt circulation pipeline to the set temperature, which is higher than the ternary chlorine The melting point of the chlorinated salt; after the temperature of the chlorinated salt and the pipeline is stabilized, start the solar simulator (73), so that the heat absorber (46) facing the light receives the radiation of the solar simulator (73); turn on the infrared thermal imager (83 ), monitoring the surface temperature distribution of the heat absorber (46); When the temperature of the outer wall surface of the pipeline of the heat absorber (46) reaches the set value, the first molten salt pump (26) is turned on to deliver the chloride salt, and the flow value of the chloride salt is monitored in real time, and the first pump is adjusted according to the flow value. The motor frequency of the molten salt pump (26) makes the chloride salt flow rate reach the set value; Step 4. When the entire experimental platform is in a thermal equilibrium state, start recording the chloride salt temperature at the inlet and outlet of the heat absorber, the light intensity information of the light-facing surface of the heat absorber, and the temperature of the light-facing surface of the heat absorber every set time Distribution, temperature distribution of the backlight surface of the heat absorber, volume flow rate of chloride salt, pressure difference between the inlet and outlet of the heat absorber, the liquid level in the first salt storage tank (76), the first salt storage tank (76) The chloride salt temperature in the second salt storage tank (81) and the temperature of the chloride salt in the second salt storage tank (81), the recording time is 30 ~ 60 minutes; Step 5. Disconnect the power supply of the first molten salt pump (26), and turn on the heat tracing equipment (11), so that the chloride salt in the heat absorber (46) flows back to the first salt storage tank (76) and the second In the second salt storage tank (81); close the solar simulator (73), heat tracing equipment (11), and resistance wire heating element (75); Step 6. Calculate the solar simulator (73) to provide to the heat sink (46) according to the light intensity information on the light-facing surface of the heat sink and the functional relationship between the energy flow value and the gray value obtained in step 1 The incident radiant energy; according to the recorded temperature of the chloride salt at the inlet and outlet of the absorber and the volume flow rate of the chloride salt, calculate the heat absorbed by the chloride salt when it flows in the absorber; combined with the incident radiant energy, calculate the heat absorber The heat loss and thermal efficiency; according to the liquid level height and chloride salt temperature in the first salt storage tank and the chloride salt temperature in the second salt storage tank, calculate the supercritical carbon dioxide in the actual tower power station through the intermediate heat exchanger to obtain The heat of the heat sink; the thermal stress analysis of the heat sink is carried out by using the temperature distribution of the heat sink facing the light surface and the temperature distribution of the heat sink backlight surface. 8. The high-temperature chloride salt photothermal and energy storage cycle experiment method according to claim 7, characterized in that, in the step 6, the method for calculating the heat loss and thermal efficiency of the heat absorber comprises the following steps: S1. Bring the gray value of each point on the light facing surface of the heat absorber into the functional relationship between the energy flow value and the gray value, calculate the energy flow value of each point on the light facing surface of the heat absorber, and obtain the entire heat absorption The distribution of energy flow on the light-facing surface of the device; S2. Calculate the incident radiant energy Q _t :

, I _j is the energy flow value of a single test point; A _j is the area occupied by a single test point; S3. Based on the temperature T _in of the inlet position of the heat absorber and the temperature T _out of the outlet position obtained in step 4, calculate the constant pressure specific heat capacity c _p,in and c _{p,out of} the chloride salt at the corresponding temperature, according to the throttling The measured value of the parts and the first differential pressure sensor, calculate the mass flow q _m of the corresponding chloride salt, and then calculate the heat Q _x absorbed by the chloride salt when flowing through the heat absorber, the calculation formula is:

; S4. Calculating the heat loss of the heat sink

, the calculation formula is:

; S5. Calculating the thermal efficiency of the heat sink

, the calculation formula is:

.

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