Solar thermal power generation system

Abstract

The invention discloses a solar thermal power generation system, which relates to the technical field of solar power generation, and comprises a heat collection system, a heat exchange system and a conversion system, the heat exchange system comprises a heat absorber and a fluidized bed heat exchanger, the heat absorber can receive sunlight collected by the heat collection system and convert the sunlight into heat, the filled high-temperature structural ceramic can be heated, and the fluidized bed heat exchanger can receive the high-temperature structural ceramic heated by the heat absorber. The high-temperature structural ceramic exchanges heat with supercritical carbon dioxide in the fluidized bed heat exchanger, the fluidized bed heat exchanger comprises an air distribution device and a bed layer, the air distribution device is arranged below the bed layer, and the fluidized bed heat exchanger can enable the high-temperature structural ceramic to be in a fluidized state; the conversion system is connected with the fluidized bed heat exchanger and can receive supercritical carbon dioxide after heat exchange of the fluidized bed heat exchanger and convert the supercritical carbon dioxide into electric energy. The heat exchange efficiency of the high-temperature structural ceramic and supercritical carbon dioxide can be improved, and the thermoelectric conversion rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of solar power generation, and in particular to a solar thermal power generation system. Background Art

[0002] In solar thermal power generation systems, the performance of heat transfer fluids has a decisive influence on the operating temperature range and heat storage method of the photothermal conversion process, which in turn affects the system efficiency of the entire solar thermal power station. Traditional heat transfer fluids such as water or mineral oil have limited performance under high temperature conditions and are difficult to meet the needs of high-temperature and efficient energy conversion. Solid particles, as heat transfer fluids and heat storage media, can make the operating temperature of the heat absorption and heat storage system in tower solar thermal power generation exceed 800°C due to their excellent thermophysical properties and high-temperature stability. At present, there is a technology that uses molten salt with supercritical carbon dioxide to achieve high-temperature power generation using solar energy based on the Brayton cycle power generation system. However, the molten salt-carbon dioxide heat exchanger used in the current solar power generation system has certain defects. For example, the molten salt energy storage heating technology is difficult and requires complex refrigeration technology and piping systems. Moreover, the molten salt-carbon dioxide heat exchanger has high temperature requirements and may have thermal resistance in a high temperature environment, which will prevent some heat from being effectively transferred to carbon dioxide, reducing the heat exchange efficiency. In addition, the viscosity of the molten salt is high, and the use of the existing heat exchanger may produce a large flow resistance, affecting the heat exchange effect. Therefore, a solar thermal power generation system is needed that can improve the heat exchange efficiency. Summary of the invention

[0003] The purpose of the present invention is to provide a solar thermal power generation system to solve the problems existing in the above-mentioned prior art, so as to improve the heat exchange efficiency and further improve the thermoelectric conversion rate.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a solar thermal power generation system, comprising

[0006] A heat collection system, wherein the heat collection system is used to collect sunlight;

[0007] A heat exchange system, wherein the heat exchange system comprises a heat absorber and a fluidized bed heat exchanger, wherein the heat absorber can receive the sunlight collected by the heat collection system and convert it into heat, and can heat the high-temperature structural ceramics filled in the heat absorber, and the fluidized bed heat exchanger is connected to the heat absorber, and the fluidized bed heat exchanger can receive the high-temperature structural ceramics after being heated by the heat absorber, and the high-temperature structural ceramics exchange heat with the supercritical carbon dioxide in the fluidized bed heat exchanger, wherein the fluidized bed heat exchanger comprises an air distribution device and a bed layer, wherein the bed layer is used to carry the high-temperature structural ceramics, and the air distribution device is arranged below the bed layer, and the air distribution device is used for ventilation to make the high-temperature structural ceramics on the bed layer present a fluidized state;

[0008] A conversion system is connected to the fluidized bed heat exchanger, and is capable of receiving supercritical carbon dioxide after heat exchange in the fluidized bed heat exchanger, and converting the heat energy carried by the supercritical carbon dioxide into electrical energy.

[0009] Preferably, the shell of the fluidized bed heat exchanger is cylindrical, the air distribution device and the bed layer are arranged inside the shell, the fluidized bed heat exchanger is provided with a supercritical carbon dioxide circulation pipeline and a high-temperature ceramic circulation cavity, the supercritical carbon dioxide circulation pipeline is fixed in the high-temperature ceramic circulation cavity in a serpentine arrangement, the supercritical carbon dioxide circulation pipeline is provided with a supercritical carbon dioxide inlet and a supercritical carbon dioxide outlet, the high-temperature ceramic circulation cavity is provided with a high-temperature structural ceramic inlet and a high-temperature structural ceramic outlet, the supercritical carbon dioxide inlet is arranged on one side of the fluidized bed heat exchanger, the high-temperature structural ceramic inlet is arranged on the other side of the fluidized bed heat exchanger, the supercritical carbon dioxide outlet is arranged at the top of the high-temperature structural ceramic inlet side, and the high-temperature structural ceramic outlet is arranged at the bottom of the supercritical carbon dioxide inlet side.

[0010] Preferably, the fluidized bed heat exchanger further comprises a fluidizing fan and a fluidizing air heater, the air inlet end of the fluidizing air heater is connected to the air outlet of the fluidizing fan, and the air outlet end of the fluidizing air heater is connected to the air distribution device.

[0011] Preferably, the solar collection system is a heliostat field composed of a plurality of heliostats.

[0012] Preferably, the heat exchange system also includes a hot storage tank and a cold storage tank, the feed port of the hot storage tank is connected to the discharge port of the heat absorber, the discharge port of the hot storage tank is connected to the inlet of the high-temperature structural ceramics, the hot storage tank is used to store the high-temperature structural ceramics that have been heated and transferred to the fluidized bed heat exchanger, the feed port of the cold storage tank is connected to the outlet of the high-temperature structural ceramics, the discharge port of the cold storage tank is connected to the feed port of the heat absorber, and the cold storage tank is used to store the high-temperature structural ceramics after heat exchange and transfer them to the heater.

[0013] Preferably, it also includes an electric heater, which is arranged on a pipeline connecting the heat storage tank and the fluidized bed heat exchanger, and can heat high-temperature structural ceramics whose temperature does not meet the standard. The electric heater is powered by photovoltaic power, wind power and off-peak electricity.

[0014] Preferably, the conversion system comprises a turbine and a generator, the turbine is connected to the supercritical carbon dioxide outlet, and the output end of the turbine is connected to the generator.

[0015] Preferably, it also includes a circulation system, which includes a regenerator, a condenser and a compressor connected in sequence, the regenerator is connected to the turbine, and can receive and process the supercritical carbon dioxide after the work is completed, the condenser is used to condense the treated supercritical carbon dioxide, the compressor is connected to the supercritical carbon dioxide inlet, and the compressor is driven by an electric motor to transport the condensed supercritical carbon dioxide to the supercritical carbon dioxide inlet.

[0016] Preferably, it also includes a water bath furnace, which is arranged on the connecting pipeline between the compressor and the fluidized bed heat exchanger, and is used to perform constant temperature treatment on the supercritical carbon dioxide.

[0017] Preferably, the high temperature structural ceramics are alumina ceramic particles.

[0018] Compared with the prior art, the present invention has achieved the following technical effects:

[0019] The heat collection system of the present invention is used to collect sunlight. The heat exchange system includes a heat absorber and a fluidized bed heat exchanger. The heat absorber can receive the sunlight collected by the heat collection system and convert it into heat, and can heat the high-temperature structural ceramics filled in the heat absorber. The fluidized bed heat exchanger is connected to the heat absorber. The fluidized bed heat exchanger can receive the high-temperature structural ceramics after being heated by the heat absorber. The high-temperature structural ceramics exchange heat with the supercritical carbon dioxide in the fluidized bed heat exchanger, wherein the fluidized bed heat exchanger includes an air distribution device and a bed layer, the air distribution device is arranged below the bed layer, the fluidized bed heat exchanger can make the high-temperature structural ceramics fluidized, and the conversion system is connected to the fluidized bed heat exchanger, and can receive the supercritical carbon dioxide after heat exchange in the fluidized bed heat exchanger and convert it into electrical energy. The air distribution device in the fluidized bed heat exchanger is arranged below the bed layer, which can make the high-temperature structural ceramics fluidized, greatly increase the contact area between the high-temperature structural ceramics and supercritical carbon dioxide, enhance the heat exchange effect, further improve the energy utilization efficiency of the entire system, and allow as much heat as possible to be transferred to the supercritical carbon dioxide for subsequent energy conversion, thereby improving the thermoelectric conversion rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the structure of a solar thermal power generation system in some embodiments of the present invention;

[0022] Figure 2 A schematic diagram of the operation of an electric heater in some embodiments of the present invention;

[0023] Figure 3 Schematic diagram of the structure of a fluidized bed heat exchanger in some embodiments of the present invention.

[0024] In the figure: 1-heliostat field; 2-heat absorber; 3-heat storage tank; 4-high temperature valve; 5-heat absorption tower; 6-electric heater; 7-silicon carbon rod; 8-fluidized bed heat exchanger; 81-fluidized fan; 82-fluidized air heater; 83-supercritical carbon dioxide inlet; 84-supercritical carbon dioxide outlet; 85-high temperature structural ceramic inlet; 86-high temperature structural ceramic outlet; 9-cold storage tank; 10-water bath furnace; 11-turbine; 12-regenerator; 13-condenser; 14-compressor; 15-generator; 16-motor; 17-air switch; 18-fuse; 19-relay; 20-power regulator; 21-ammeter; 22-transformer. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a solar thermal power generation system to solve the problems existing in the prior art, improve the heat exchange efficiency, and further improve the thermoelectric conversion rate.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1-Figure 3As shown, the present invention provides a solar thermal power generation system, including a heat collection system, a heat exchange system and a conversion system. The heat collection system is used to collect sunlight; the heat exchange system includes a heat absorber 2 and a fluidized bed heat exchanger 8. The heat absorber 2 can receive the sunlight collected by the heat collection system and convert it into heat, and can heat the high-temperature structural ceramics filled in the heat absorber 2. The fluidized bed heat exchanger 8 is connected to the heat absorber 2. The fluidized bed heat exchanger 8 can receive the high-temperature structural ceramics after being heated by the heat absorber 2. The high-temperature structural ceramics exchange heat with the supercritical carbon dioxide in the fluidized bed heat exchanger 8, wherein the fluidized bed heat exchanger 8 includes an air distribution device and a bed layer. The bed layer is used to carry the high-temperature structural ceramics. The air distribution device is arranged below the bed layer. The air distribution device is used for ventilation to fluidize the high-temperature structural ceramics on the bed layer, so the fluidized bed heat exchanger 8 can make the high-temperature structural ceramics fluidized; the conversion system is connected to the fluidized bed heat exchanger 8, and can receive the supercritical carbon dioxide after heat exchange by the fluidized bed heat exchanger 8, and convert the energy carried by the supercritical carbon dioxide into electrical energy. The air distribution device in the fluidized bed heat exchanger 8 is arranged below the bed layer, which can make the high-temperature structural ceramics fluidized, greatly increase the contact area between the high-temperature structural ceramics and the supercritical carbon dioxide, enhance the heat exchange effect, and further improve the energy utilization efficiency of the entire system, so that as much heat as possible can be transferred to the supercritical carbon dioxide for subsequent energy conversion, thereby improving the thermoelectric conversion rate.

[0029] And supercritical carbon dioxide is used as a medium for heat exchange and energy conversion. Supercritical carbon dioxide has good thermophysical properties, such as large specific heat capacity and good fluidity. It can efficiently carry heat to participate in the energy conversion link, which helps to improve the ability of the entire system to finally convert the collected solar energy into electrical energy. High-temperature structural ceramics are used, which have many excellent characteristics such as high temperature resistance and good chemical stability. They can withstand high temperature environment for a long time in the heat absorber 2 and maintain stable performance. At the same time, they can also reliably participate in the heat exchange process in the fluidized bed heat exchanger 8, reducing the risk of system failure caused by poor material performance and ensuring stable and long-term operation of the system.

[0030] Among them, the main technical parameters of the absorber 2 are: the geographical location is 40.4°N, 115.9°E, the rated efficiency of the mirror field design point is 81.72%, the rated power of the generator 15 is 200kW, the rated efficiency of the absorber 2 is 70.0%, the heat absorption tower 5 used to place the absorber 2 is 120m high, the annual average optical efficiency of the mirror field is 66.7%, the outlet parameters of the absorber 2, solid particles 800℃, high temperature heat storage temperature 800℃, the inlet parameters of the absorber 2, solid particles 500℃, low temperature heat storage temperature 500℃, the structure of the absorber 2, gravity-driven accumulation and falling type, the control mode of the heliostat 1 is BCS correction, the opening size of the absorber 22 is 2.5m×2.4m, the design point is 12:00 noon on the vernal equinox, 1000W / m 2, heat storage system solid particle turbine 11 inlet 550℃, 10MPa, supercritical carbon dioxide, heat storage capacity, 20 tons of particles, the area of ​​each heliostat in heliostat field 1 is 100m 2 .

[0031] In some embodiments, the shell of the fluidized bed heat exchanger 8 is cylindrical, the air distribution device and the bed layer are arranged in the shell, the air distribution device is arranged below the bed layer, the fluidized bed heat exchanger 8 is provided with a supercritical carbon dioxide flow pipeline and a high-temperature ceramic flow cavity, the supercritical carbon dioxide flow pipeline is arranged in a serpentine shape and fixed in the high-temperature ceramic flow cavity, the supercritical carbon dioxide flow pipeline is provided with a supercritical carbon dioxide inlet 83 and a supercritical carbon dioxide outlet 84, the high-temperature ceramic flow cavity is provided with a high-temperature structural ceramic inlet 85 and a high-temperature structural ceramic outlet 86, the supercritical carbon dioxide inlet 83 is provided on one side of the fluidized bed heat exchanger 8, the high-temperature structural ceramic inlet 85 is provided on the other side of the fluidized bed heat exchanger 8, the supercritical carbon dioxide outlet 84 is provided at the top of the high-temperature structural ceramic inlet 85 side, and the high-temperature structural ceramic outlet 86 is provided at the bottom of the supercritical carbon dioxide inlet 83 side. The supercritical carbon dioxide circulation pipeline is arranged in a serpentine shape and fixed in the high-temperature ceramic circulation cavity. Compared with the simple straight pipeline arrangement, the flow length of the supercritical carbon dioxide in the circulation pipeline is greatly increased, so that it can have a more sufficient contact time and contact area with the high-temperature structural ceramics in a limited space, enhance the heat exchange effect, and more efficiently absorb the heat carried by the high-temperature structural ceramics, which helps to improve the heat exchange efficiency of the entire heat exchanger.

[0032] The supercritical carbon dioxide outlet 84 is arranged at the top of the high-temperature structural ceramic inlet 85 side, and the high-temperature structural ceramic outlet 86 is arranged at the bottom of the supercritical carbon dioxide inlet 83 side, which conforms to the natural flow characteristics of the fluid in the heat exchanger and the law of heat transfer, and is conducive to the high-temperature structural ceramics to flow smoothly from top to bottom under the action of gravity. At the same time, supercritical carbon dioxide enters from the bottom and gradually heats up and flows upward, and finally flows out from the top, making the entire heat exchange process orderly and efficient, and can ensure the stability and adequacy of the heat exchange.

[0033] In some embodiments, the fluidized bed heat exchanger 8 also includes a fluidizing fan 81 and a fluidizing air heater 82, the air inlet end of the fluidizing air heater 82 is connected to the air outlet of the fluidizing fan 81, and the air outlet end of the fluidizing air heater 82 is connected to the air distribution device. The fluidizing fan 81 can continuously and stably provide the required airflow for the entire fluidization process, ensure that there is enough air volume entering the system, so that the high-temperature structural ceramics can always maintain a fluidized state in the fluidized bed heat exchanger 8, which plays a key role in increasing the contact area between the high-temperature structural ceramics and supercritical carbon dioxide, ensuring the uniformity and efficiency of heat exchange, and avoiding the situation of poor local heat exchange due to unstable fluidization. By adjusting the operating parameters of the fluidizing fan 81 (such as air volume, wind pressure, etc.), the fluidization degree of the high-temperature structural ceramics can be flexibly controlled. According to different working conditions, such as different heat exchange requirements, different material flow rates, etc., the fluidization state is accurately adjusted to optimize the working performance of the entire fluidized bed heat exchanger 8, so that it can adapt to a variety of complex actual operating conditions.

[0034] The fluidized air heater 82 can heat the air from the fluidizing fan 81. After the heated fluidized air enters the air distribution device, it not only plays a role in fluidizing the high-temperature structural ceramics, but also carries an additional portion of heat. This portion of heat will be transferred to the high-temperature structural ceramics and supercritical carbon dioxide, further improving the heat source in the entire heat exchanger, helping to enhance the heat exchange effect, so that the supercritical carbon dioxide can absorb more heat, improve the heat utilization efficiency, and promote the subsequent power conversion and other links to be better carried out. When facing complex working conditions such as different initial temperatures, different flow rates of supercritical carbon dioxide, and different high-temperature structural ceramic feed states, the fluidized air heater 82 can change the temperature of the fluidized air by adjusting the heating power, etc., and cooperate with the fluidizing fan 81 to jointly adjust the fluidization state and the heat brought into the system, so that the fluidized bed heat exchanger 8 can quickly adapt to different operating requirements, ensure the stable and reliable operation of the system, and play a good heat exchange function in a variety of application scenarios.

[0035] The operating parameters of the fluidized bed heat exchanger 8 are as follows: design parameters of the supercritical carbon dioxide working fluid side, working fluid flow rate 16.6 t / h, inlet pressure 15 MPa, inlet temperature 370°C, outlet temperature 550°C, carbon dioxide density 109 kg / m 3 The design parameters of high temperature structural ceramic particles working fluid side are: inlet temperature 700℃, outlet temperature 500℃, maximum inlet temperature 800℃, working fluid flow rate 34t / h, specific heat J / 1000(kg·K), heat transfer coefficient 1000W / (m 2 ·K), heat transfer coefficient 1750W / (m 2 ·K).

[0036] In some embodiments, the heat collection system is a heliostat field 1 composed of multiple heliostats. The heliostat field 1 formed by the combination of many heliostats can cover a larger area, greatly increasing the range of sunlight that can be collected, thereby providing a more sufficient heat source for subsequent heat absorption, heat exchange, and energy conversion. It should be noted that the heliostat field 1 uses 62 heliostats as concentrators with a total area of ​​6,200 square meters. The 62 heliostats can generate 200KW of electricity, and the power of the turbine 11 described later is 200KW, which is consistent with each other.

[0037] In some embodiments, the heat exchange system further includes a hot storage tank 3 and a cold storage tank 9, the feed port of the hot storage tank 3 is connected to the discharge port of the heat absorber 2, the discharge port of the hot storage tank 3 is provided with a high-temperature valve 4 connected to the high-temperature structural ceramic inlet 85, and the high-temperature valve 4 can control the outflow of the high-temperature structural ceramic, the hot storage tank 3 is used to store the high-temperature structural ceramics after heating and transmit them to the fluidized bed heat exchanger 8, the feed port of the cold storage tank 9 is connected to the high-temperature structural ceramic outlet 86, the discharge port of the cold storage tank 9 is connected to the feed port of the heat absorber 2, and the cold storage tank 9 is used to store the high-temperature structural ceramics after the heat exchange is completed and transmit them to the heater. The hot storage tank 3 can flexibly adjust the supply of high-temperature structural ceramics according to the actual operation requirements of the fluidized bed heat exchanger 8. When the fluidized bed heat exchanger 8 needs a higher heat input to cope with high-load power generation requirements, the high-temperature structural ceramic flow rate output from the hot storage tank 3 to the fluidized bed heat exchanger 8 can be appropriately increased to achieve effective regulation of heat in time and flow, and optimize the working efficiency of the entire heat exchange system. The cold storage tank 9 is provided to improve the circulation loop of the high-temperature structural ceramics. After the heat exchange is completed, the high-temperature structural ceramics are stored in the cold storage tank 9, and then transmitted back to the heat absorber 2 for reheating, so that the high-temperature structural ceramics can repeatedly participate in the heat exchange process, realize the recycling of the high-temperature structural ceramics, avoid the waste of resources, maximize its role in heat transfer, and improve the utilization efficiency of the high-temperature structural ceramics of the entire system.

[0038] It should be noted that the heat absorber 2 and the heat storage tank 3 are arranged in the heat absorption tower 5, the heat storage tank 3 is located below the heat absorber 2, and a high-temperature valve 4 is arranged at the discharge port of the heat storage tank 3.

[0039] In some embodiments, the solar thermal power generation system further includes an electric heater 6, which is arranged on the pipeline connecting the heat storage tank 3 and the fluidized bed heat exchanger 8, and can heat the high-temperature structural ceramics whose temperature does not meet the standard. A silicon carbon rod 7 is arranged inside the electric heater 6, and the electric heater 6 is powered by photovoltaic, wind power and valley electricity. The electric heater 6 is arranged on the pipeline connecting the heat storage tank 3 and the fluidized bed heat exchanger 8. When the temperature of the high-temperature structural ceramics does not meet the ideal heat exchange requirements, the electric heater 6 can heat them in time to supplement the heat, ensuring that the high-temperature structural ceramics entering the fluidized bed heat exchanger 8 always carry enough heat, thereby maintaining a stable and efficient heat exchange process, ensuring that the energy conversion chain of the entire solar thermal power generation system will not be interrupted due to the high-temperature structural ceramics not meeting the temperature standards, and improving the stability and reliability of the system operation. Faced with complex working conditions such as different weather conditions and lighting conditions, for example, when it is cloudy and the solar energy collected by the heat collection system is limited, and the heat output of the high-temperature structural ceramic of the absorber 2 is insufficient, the electric heater 6 can play a key role and supplement the heat on demand, so that the system can still maintain a relatively stable power generation capacity under a changing external environment, and enhance the system's adaptability to different working conditions. The electric heater 6 is provided with electricity by photovoltaics, wind power and valley electricity to achieve the coordinated utilization of multiple energy sources. Photovoltaic and wind power are clean energy sources in themselves, which are consistent with the overall concept of solar thermal power generation systems, and further enhance the green and environmentally friendly attributes of the entire energy utilization process. The use of valley electricity improves the comprehensive utilization efficiency of power grid electricity, avoids the waste of electricity during valley periods, and realizes the optimal configuration across time periods and energy types, so that different forms of energy can be used in the system to their full potential, improve the overall efficiency of energy utilization, achieve energy self-sufficiency, and reduce operating costs.

[0040] Specifically, the electric heater 6 is set as follows:

[0041] The electric heater 6 includes an air switch 17 , a fuse 18 , a relay 19 , a power regulator 20 , an ammeter 21 , a transformer 22 , and a silicon carbon rod 7 .

[0042] Photovoltaic power, wind power and valley power are connected to the input end of the air switch 17. When the current in the circuit exceeds the rated value, the air switch 17 will automatically disconnect the circuit to prevent the equipment from being damaged due to overload. When a short circuit occurs in the circuit, the air switch 17 will quickly cut off the power supply to prevent fire caused by excessive short-circuit current. The output end of the air switch 17 is connected to the fuse 18. The fuse 18 is a current protector. When the current exceeds the specified value, the fuse 18 will melt the fuse with the heat generated by itself, thereby disconnecting the circuit. This design principle allows the fuse 18 to quickly melt and cut off the circuit after the current exceeds a certain value for a period of time, preventing the short-circuit current from causing damage to the equipment and system. The other end of the fuse 18 is connected to the relay 19. The relay 19 is an electrical control device, which is mainly used to realize the functions of switching, separation, timing, protection and control of the circuit. The main function of the relay 19 in this embodiment is to control the on and off of the AC circuit. The other end of the relay 19 is connected to the input end of the power regulator 20. The main function of the power regulator 20 is to protect the load equipment and automatically adjust the power. The power is automatically adjusted through program control to ensure that the equipment operates at an appropriate power and adjust the temperature of the electric heater 6. The ammeter 21 reads the AC current through the AC transformer on the AC circuit. The AC transformer is mounted on the AC main circuit. The maximum current of the heater is 150A. The input end of the transformer 22 is connected to the output end of the power regulator 20. The transformer 22 is a device that uses the principle of electromagnetic induction to change the AC voltage. Its main components include a primary coil, a secondary coil and an iron core (or a magnetic core). The transformer 22 uses the principle of electromagnetic induction. When an AC current is passed through the primary coil, an AC magnetic flux is generated in the iron core, so that a voltage is induced in the secondary coil. This transformer 22 converts AC380V into AC36V. 36V is a safe voltage that the human body can withstand. The output end of the transformer 22 is connected to the silicon carbon rod 7. The heating principle of the silicon carbon rod 7 is based on its resistance characteristics, and the electrical energy is converted into thermal energy. The silicon carbon rod 7 is a non-metallic electric heating element, and the main raw material is high-purity green hexagonal silicon carbide. Its resistivity changes with the change of temperature, showing nonlinear characteristics. At room temperature, the resistivity of the silicon carbon rod 7 is relatively large. As the temperature increases, the resistivity decreases rapidly. When a certain temperature (such as 800 degrees Celsius) is reached, the resistivity reaches the minimum, and then the temperature continues to rise, and the resistivity rises slowly again. This characteristic enables the silicon carbon rod 7 to effectively convert electrical energy into thermal energy when it is powered on.

[0043] In some embodiments, the conversion system includes a turbine 11 and a generator 15, the turbine 11 is connected to the supercritical carbon dioxide outlet 84, and the output end of the turbine 11 is connected to the generator 15. The turbine 11 is connected to the supercritical carbon dioxide outlet 84, and the supercritical carbon dioxide carries the heat absorbed from the fluidized bed heat exchanger 8 and has a high energy. After the supercritical carbon dioxide enters the turbine 11, it can drive the impeller of the turbine 11 to rotate at a high speed, and efficiently convert the thermal energy into mechanical energy. Its energy conversion process is based on the good thermophysical properties and flow characteristics of supercritical carbon dioxide, so that this conversion link can make full use of thermal energy, reduce energy loss, and provide a sufficient and stable power source for the subsequent power generation of the generator 15. The output end of the turbine 11 is connected to the generator 15 to realize the conversion of mechanical energy to electrical energy. The mechanical energy generated by the rotation of the turbine 11 can be directly transmitted to the generator 15, driving the rotor of the generator 15 to rotate, and then efficiently generating electrical energy through the principle of electromagnetic induction. The energy conversion chain from thermal energy to mechanical energy to electrical energy based on the Brayton cycle is smooth and efficient, which improves the power generation efficiency of the entire solar thermal power generation system. Preferably, the motor type of the generator 15 is permanent magnet synchronous, current 810A, power supply voltage 380V, rated power 500KW, rated speed 3000rpm, working system S1, insulation grade H, protection grade IP54, cooling method oil cooling, operating temperature 4℃ to 40℃, bearing type ceramic ball rolling bearing, motor weight 4t. The intake temperature of turbine 11 is 550℃, the intake pressure is 14.1MPa, the mass flow rate is 10.5Kg / S, the outlet pressure is 8.8MPa, the wheel diameter is 70mm, the speed is 24000rpm, the shaft power is 500KW, and the turbine 11 type is four-stage axial flow with equal diameter.

[0044] In some embodiments, the solar thermal power generation system also includes a circulation system, which includes a regenerator 12, a condenser 13 and a compressor 14 connected in sequence. The regenerator 12 is connected to the turbine 11, and can receive and process the supercritical carbon dioxide after the work is completed. The condenser 13 is used to condense the treated supercritical carbon dioxide. The compressor 14 is connected to the supercritical carbon dioxide inlet 83, and the compressor 14 is driven by the motor 16 to transport the condensed supercritical carbon dioxide to the supercritical carbon dioxide inlet 83. The regenerator 12 recovers part of the residual heat carried by the supercritical carbon dioxide. This part of the recovered heat can be transferred to the supercritical carbon dioxide that is about to enter the turbine 11, so as to realize the internal recycling of heat, improve the thermal efficiency of the whole system, reduce the waste of heat, and enable the supercritical carbon dioxide to obtain additional heat supplement before entering the turbine 11, thereby improving its working capacity and increasing the power generation. The condenser 13 is used to condense the treated supercritical carbon dioxide, and the state of the supercritical carbon dioxide can be stably adjusted to a state suitable for the compressor 14 to process, so as to avoid the supercritical carbon dioxide from causing adverse effects on subsequent compression and other links due to abnormal state. The circulation system composed of the regenerator 12, the condenser 13 and the compressor 14 allows the supercritical carbon dioxide to continuously circulate in the system and participate in the energy conversion process. After a series of treatments, the supercritical carbon dioxide flowing out of the turbine 11 can return to its initial state and be transported to the supercritical carbon dioxide inlet 83 to enter the system circulation again, ensuring the sustainable use of the supercritical carbon dioxide.

[0045] Among them, the compressor 14 has an inlet temperature of 35°C, an inlet pressure of 8.2MPa, a working fluid flow rate of 10.5Kg / S, an outlet pressure of 15MPa, an impeller diameter of 78mm, a speed of 28000rpm, a shaft power of 250KW, a rated speed of 28000rpm, a shaft power of 185KW, and a two-stage centrifugal series type. The motor 16 is a high-speed direct drive motor, with a power supply voltage of 380V, a rated power of 250KW, a rated speed of 28000rpm, an operating speed range of 21000-28000rpm, a motor pole number of 2, a starting mode of variable frequency starting, a protection level of H, an insulation level of IP56, a cooling mode of water cooling, a cooling water temperature of 0°C to 40°C, a bearing temperature of <85°C, and a coil temperature of <155°C. The parameters of the high-speed motor inverter are as follows: input frequency 50HZ, output frequency 0-500HZ, rated output current 600A, working voltage 380V, cooling mode of air cooling, and working efficiency 96%.

[0046] In some embodiments, the solar thermal power generation system further includes a water bath 10, which is disposed on the connecting pipeline between the compressor 14 and the fluidized bed heat exchanger 8. The water bath 10 is used to perform constant temperature treatment on the supercritical carbon dioxide. The water bath 10 can accurately maintain the temperature of the supercritical carbon dioxide within a specific suitable range, so that it enters the fluidized bed heat exchanger 8 at a stable temperature state to participate in heat exchange. Stable temperature helps to ensure that the heat exchange process is carried out in an ideal state, avoids problems such as unstable heat exchange efficiency and thermal stress changes caused by supercritical carbon dioxide temperature fluctuations, and improves the predictability and accuracy of the entire heat exchange process.

[0047] In some embodiments, the high temperature structural ceramic is alumina ceramic particles. Alumina ceramic particles have excellent high temperature resistance, can basically withstand 1300°C, and can maintain stable physical and chemical properties for a long time in a high temperature environment. In the solar thermal power generation system, whether it is receiving high heat converted from sunlight in the absorber 2, or participating in the heat exchange process with supercritical carbon dioxide in the fluidized bed heat exchanger 8, it can withstand the corresponding high temperature and will not easily soften, deform, melt, etc., ensuring that the entire heat exchange link can be carried out stably and continuously, and the price is relatively low. It should be noted that other types of high temperature structural ceramics, such as silicon carbide, silicon nitride and other particles, can also be used, but the cost is relatively high.

[0048] The specific commissioning and use process of the solar thermal power generation system is as follows:

[0049] The heliostats have been eliminated, and the heliostats are flexible. The operation status of the host computer is normal and ready for use at any time. The heating surface of the absorber 2 is complete, the display of each measuring point is normal, the valve switch is normal, the bucket elevator has been debugged and is available. The bucket elevator is used to transport alumina ceramic particles, mainly to transport alumina ceramic particles vertically upward to the absorber 2. The calibration and correction control system and the mirror field control system have been debugged and optimized, and are ready for use. The crane, electric hoist crane and related vehicles used for the transportation of alumina ceramic particles have been overhauled and are ready for the transmission and transportation of alumina ceramic particles. The liquid level of the carbon dioxide gas storage tank is at a high level, meeting the requirements for the whole set of startup. The carbon dioxide liquid booster pump has passed the trial run, the inverter loading is normal, and has good adjustment characteristics. The heating test of each group of electric heaters 6 of the water bath furnace 10 is normal, and the water temperature control and liquid level control of the water bath furnace 10 are in the automatic position. The flue gas system of the fluidized bed heat exchanger 8 has been debugged, and the fluidized fan 81 has reliable load adjustment capabilities. The instruments involved in the entire startup are put into operation and the displays are normal.

[0050] All logic protection and alarm signal calibrations have been completed; the carbon dioxide heat exchanger empty plate resistance test and critical fluidization test have passed, and are ready for hot commissioning. The entire carbon dioxide thermal system has been purged and accepted, and the temporary system has been restored. The turbine 11, load machine, compressor 14 and auxiliary oil pump have been tested, and there are no major defects that affect the start-up of the entire system. The desalted water supply system, circulating water system, mechanical ventilation cooling tower system, auxiliary machine cooling water system and other public systems have been debugged and are ready for reliable commissioning. Under the guidance of a third party, the temporary measuring points used for performance testing have been installed. The outlet cold tank of the fluidized bed heat exchanger 8 is emptied and connected to a mobile storage tank with a capacity of 2 tons.

[0051] The test steps are as follows: Heliostat field 1 and receiver 2 start together. The control system of heliostat field 1 is mainly composed of the bottom layer Schneider m238 PLC, the middle layer Schneider Premium PLC, the upper monitoring software Citect and the communication part. The bottom layer Schneider m238 is the direct controller of each action of the heliostat; the central control Premium organizes and coordinates the entire mirror field, and the upper command is distributed to all heliostats in the mirror field after being organized by Premium. There are currently 100 heliostats. The upper monitoring software Citect is a human-machine interface that intuitively presents the system operation status. Wireless communication is the bridge for data transmission between 100 Schneider m238 and Premium.

[0052] The direct radiation DNI in the normal direction is greater than 300w / m 2 , under the condition that the wind speed at a height of 5m is not greater than 10m / s, the following operations can be performed: the heliostat field 1 is moved to the preparation location; the infrared monitor of the heat absorber 2 is turned on and reaches the visual state; after receiving the heat absorber 2 ready command, the heliostat field 1 is started;

[0053] Each time the heliostat is connected to the daylighting port of the absorber 2, the energy is 10% of the total amount of heliostats, about 500m 2 Heliostat;

[0054] The operator observes the heliostat that overflows the light-collecting port through manual vision, and makes corrections, and stops the mirror operation before the correction; the temperature of the alumina ceramic particles at the outlet of the absorber 2 is controlled by adjusting the focusing and defocusing of the heliostat and the flow of the alumina ceramic particles in the absorber 2, and the maximum temperature does not exceed 800°C; if the primary heating temperature of the alumina ceramic particles does not reach the target value, the heated alumina ceramic particles are sent to the inlet of the absorber 2 through a bucket elevator, and are cyclically heated to gradually increase to the target temperature; the heating power is appropriately selected, and the temperature rise of the alumina ceramic particles at the outlet should not be greater than 20°C / minute; after the heating work is completed, the operator of the absorber 2 issues a shutdown command and moves the heliostat away from the absorber 2; after the heating work is completed, the heliostat returns to a safe position; the condition of the heliostat is checked, the condition of each heliostat is recorded in writing, and the faulty heliostat is inspected. 700℃ hot alumina ceramic particles are exported from the absorber 2 to the heat storage tank; the heat storage tank valve is opened to let the high-temperature alumina ceramic particles flow into the heat storage tank 3, and the alumina ceramic particles in the heat storage tank 3 are poured into the 25T heat storage tank. The total mass of the stored alumina ceramic particles is 25T, and the temperature is 700℃.

[0055] Accurately measuring the temperature of solid alumina ceramic particles, especially the temperature of the outlet alumina ceramic particles, is very important for controlling the thermal performance of the electric furnace. After the solid alumina ceramic particles are discharged from the outlet of the conical funnel, they fall freely under the action of gravity, and the local phase fraction of the alumina ceramic particles decreases rapidly with the increase of the falling distance. At the outlet temperature measuring point of the alumina ceramic particles, due to the fast flow rate of the alumina ceramic particles and the low phase fraction of the alumina ceramic particles, it is difficult to determine whether the measured value of the thermocouple is the temperature of the solid alumina ceramic particles. In addition, if the thermocouple is arranged at the outlet of the solid alumina ceramic particles, the presence of the thermocouple will reduce the flow area of ​​the alumina ceramic particles, reduce the flow rate of the alumina ceramic particles, and easily cause blockage.

[0056] In order to improve the accuracy of alumina ceramic particle temperature measurement, the temperature data of alumina ceramic particles should be collected when the alumina ceramic particles are piled up. Compared with the outlet, alumina ceramic particles are more likely to pile up at the inlet. Open the gate valve at the outlet of the transfer tank so that the mass flow rate of alumina ceramic particles flowing out of the transfer tank is greater than the maximum flow rate of the electric furnace. The excess alumina ceramic particles will pile up at the inlet. When the alumina ceramic particles at the inlet submerge the thermocouple measuring point, measure the inlet temperature of the alumina ceramic particles. The inlet temperature measuring points are represented as T1, T2, and T3 respectively.

[0057] At the outlet, a conical funnel with a smaller outlet diameter is used to obtain the solid alumina ceramic particles in a stacked state. Since the outlet diameter of the lower funnel is smaller than the outlet diameter of the upper funnel, the solid alumina ceramic particles flowing out of the upper funnel will be collected and stacked again in the lower funnel. Inserting a K-type thermocouple in the lower funnel can measure the outlet temperature of the alumina ceramic particles. Due to the low effective thermal conductivity of the moving bed (0.5W / (m·K) at 700°C) and the low mixing intensity of the alumina ceramic particles in the moving bed, the thermocouple measurement results only represent the local temperature. Installing only one thermocouple may result in the measurement results not being able to represent the overall temperature of the alumina ceramic particles. A K-type thermocouple was inserted at three different positions at the inlet to measure the inlet temperature of the alumina ceramic particles, two S-type thermocouples were inserted in the electric furnace to measure the furnace temperature, and three temperature measurement points were arranged at the outlet, and the arrangement of the outlet temperature measurement points of the alumina ceramic particles is not shown. The accuracies of the K-type and S-type thermocouples used are ±0.75%T and ±0.25%T respectively, where T is the measurement point result in °C. In addition, the diameter of the K-type thermocouple used is 1mm, and the heat capacity is small, which is conducive to reducing the uncertainty of temperature measurement. The steps of the hot experiment include:

[0058] (1) Preheat the electric furnace to 1000°C and close the high-temperature valve 4 at the outlet of the hot storage tank 3.

[0059] (2) Adjust the furnace power to 100%.

[0060] (3) Open the outlet valve of the alumina ceramic particle transfer tank.

[0061] (4) Ensure that the temperature measuring point of the inlet alumina ceramic particles is submerged by the alumina ceramic particles during the experiment.

[0062] (5) Record the inlet alumina ceramic particle temperature, outlet alumina ceramic particle temperature and electric furnace temperature during the experiment.

[0063] (6) After the alumina ceramic particle transfer tank is emptied, it is hoisted to the ground.

[0064] (7) Open the high-temperature valve 4 at the discharge port of the hot storage tank 3 and fill the alumina ceramic particles into the alumina ceramic particles transfer tank.

[0065] (8) Close the outlet valve of the hot alumina ceramic particle storage tank and hoist the alumina ceramic particle transfer tank above the electric furnace.

[0066] (9) Repeat (3) to (8).

[0067] Considering that the mass flow rate of solid alumina ceramic particles in a single tube remains unchanged in the hot experiment, the inlet temperature of alumina ceramic particles, the electric furnace temperature and the outlet temperature of alumina ceramic particles under steady-state conditions are selected to evaluate the thermal performance of the electric furnace and verify the effectiveness of the proposed practical method.

[0068] When the water bath furnace 10 is started, the bypass valve of the water inlet of the water bath furnace 10 gasifier is opened to control the water inlet speed; when the liquid level is higher than 1.5m, the water injection is stopped, and the general liquid level is maintained at 1.5m-1.6m; the DC resistance of each group of electric heaters 6 is measured to confirm that the electric heaters 6 are intact; the water temperature of the water bath furnace 10 is set to 75℃ and turned to the "automatic position"; after the booster pump is started, the water temperature of the water bath furnace 10 and the carbon dioxide outlet temperature are closely monitored. Start the booster pump, press the closed system, check that the insulation of the carbon dioxide booster pump is good, and supply power; check that the electric valve at the outlet of the carbon dioxide booster pump, the electric valve at the outlet of the water bath furnace 10 gasifier, and the electric regulating valve at the inlet of the fluidized bed heat exchanger 8 are open; close the electric discharge valve on the gas side from the carbon dioxide storage tank to the carbon dioxide booster pump, and the electric exhaust valve in front of the outlet electric door; slightly open the manual discharge valve at the outlet of the fluidized bed heat exchanger 8 for an open test; open the manual primary, secondary, and tertiary doors on the gas side from the carbon dioxide storage tank to the carbon dioxide booster pump, and control the opening degree of the manual primary door on the gas side from the carbon dioxide storage tank to the carbon dioxide booster pump during the opening process, press and pre-cool the carbon dioxide booster pump, and the gas side pressure reaches about 2.0MPa;

[0069] Open the manual primary, secondary and tertiary doors from the CO2 gas storage tank to the CO2 booster pump liquid side. During the opening process, control the opening of the manual primary door from the CO2 gas storage tank to the CO2 booster pump liquid side to deeply precool the CO2 booster pump for a precooling time of no less than 30 minutes; check the frosting condition of the CO2 booster pump housing to determine whether the CO2 booster pump is precooled evenly;

[0070] The programmable logic controller PLC starts the carbon dioxide booster pump, and the pump starts at a minimum frequency of 25Hz. Check that the pump operating parameters are normal and the plunger sealing ring is leak-proof; use the electric regulating valve at the inlet of the fluidized bed heat exchanger 8 to adjust the outlet pressure of the water bath furnace 10, and supply carbon dioxide to the closed system through the water bath furnace 10 and press. Preheat the fluidized bed heat exchanger 8, start the fluidizing fan 81, and establish the initial heating air volume; start the fluidizing air heater 82 at the outlet of the fluidizing fan 81, and load the power output to 100%; adjust the variable frequency output of the fluidizing fan 81, try to reduce the air volume, and preheat the fluidized bed heat exchanger 8 with a small air volume. The inlet air temperature of the fluidizing fan 81 does not exceed 220℃; start preheating in the first 48 hours, and the internal temperature of the fluidized bed heat exchanger 8 is preheated to 300℃, and the preheating of the fluidized bed heat exchanger 8 is completed. Closed cycle is established, confirm that the dry gas sealing gas and isolation gas of compressor 14 are put into normal operation; confirm that the lubricating oil system of compressor 14 is working normally; check and confirm that the anti-surge valve of compressor 14 is fully open; after the closed system is pressed, open the inlet and outlet electric valves of compressor 14, start compressor 14, check and confirm that the various parameters of compressor 14 are operating normally; keep the inlet regulating valve and shut-off valve of turbine 11 fully closed, keep the bypass valve of turbine 11 fully open, start compressor 14, gradually increase the speed of compressor 14, and compressor 14 first increases the speed to the high speed range (75% rated speed); compressor 14 should not stay in the critical zone for a long time when running (the critical zone speed of compressor 14 is 10521rpm and 12688rpm), and gradually increase the closed carbon dioxide pressure to a certain value. Feed the fluidized bed heat exchanger 8, establish the parameters of the car, and after the closed cycle is established, the fluidized bed feed valve should be opened immediately.

[0071] Rapidly increase the temperature of fluidized bed heat exchanger 8, and quickly increase the temperature of carbon dioxide at the outlet of fluidized bed heat exchanger 8; the feed temperature of fluidized bed heat exchanger 8 rises, slowly increases the flow rate of compressor 14 and the working medium temperature at the outlet of main heat exchanger, adjusts the cooling water volume of precooler to ensure the stability of the working medium temperature at the inlet of compressor 14, and the working medium circulates through turbine 11 bypass until the outlet temperature of the working medium side of the main heat exchanger reaches 200℃; turbine 11 is rushed and connected to the grid, and the opening of the anti-surge valve of compressor 14 is adjusted to realize the output regulation of compressor 14, and at the same time, the turbine 11 bypass is adjusted to realize the target speed of turbine 11.

[0072] During the start-up of the carbon dioxide turbine 11, the temperature and pressure are increased simultaneously. The system pressure is increased by increasing the speed of the compressor 14, and the working fluid temperature is increased by increasing the power of the main heat exchanger. The working fluid temperature increase rate is not higher than 1°C / min, and the working fluid is gradually charged into the system. The turbine 11 increases the speed step by step according to the speed increase curve. The speed increase rate is set to 2000rpm / min in the two speed increase sections (6500rpm-8500rpm, 10500rpm-12500rpm) that cross the critical speed (7500rpm, 11000rpm); the speed increase rate in the other conventional speed increase sections is 500rpm / min. When the speed reaches the above speed levels, the stabilization time at each speed level is not less than 5min. When the working fluid temperature increase rate cannot meet the requirements of the speed increase curve, the turbine 11 and the compressor 14 can be maintained at a constant speed state and kept for a period of time to wait for the working fluid to heat up until the requirements are met.

[0073] Monitor all monitoring instruments of turbine 11 and compressor 14 and see that they are normal and there are no alarm signals. Monitor the vibration of each shaft and the metal temperature of the bearing. Record all parameters comprehensively. The operator manually connects the unit to the load, and the connected load is consumed in the form of heat load. Pay close attention to the operation mode of the heat load. After connecting the load, check the vibration of the unit, bearing temperature, return oil temperature, lubricating oil pressure, turbine 11 inlet working medium temperature, etc. Check that the regenerator 12 is in normal operation and the heat exchange capacity meets the design. Gradually close the turbine 11 bypass valve, increase the turbine 11 intake flow, and gradually increase the load. Gradually close the turbine 11 bypass and put it into automatic operation. Comprehensively check whether all parameters have reached the rated value. Comprehensively check the automatic and protection input conditions.

[0074] The fluidized bed heat exchanger 8 is subjected to a closed-loop test in parallel with the entire startup, and the installation of the measuring points is completed. The measuring point names and locations are as follows: high-temperature structural ceramic inlet 85 temperature, high-temperature structural ceramic outlet 86 temperature, supercritical carbon dioxide inlet 83 temperature, supercritical carbon dioxide outlet 84 temperature, supercritical carbon dioxide inlet 83 pressure, supercritical carbon dioxide outlet 84 pressure, fluidizing air inlet temperature, fluidizing air outlet temperature, fluidizing air inlet pressure, fluidizing air outlet pressure. The alumina ceramic particle discharge electric valve at the fluidized bed outlet and the discharge pipe from the cold storage tank 9 (volume 25 tons) to the mobile storage tank (volume 1.2 tons) electric valve are opened. After the preheating of the fluidized bed heat exchanger 8 is completed, the hot alumina ceramic particle feed valve at the inlet of the fluidized bed heat exchanger 8 is opened to speed up the feeding speed. When the mobile storage tank with a volume of 1.2 tons is full, the discharge pipe from the cold storage tank 9 (volume 25 tons) to the mobile storage tank (volume 1.2 tons) electric valve is closed, and the time t is recorded. 1According to the demand parameters of the turbine 11, the speed of feeding alumina ceramic particles to the fluidized bed heat exchanger 8 is adjusted, and the discharge is carried out in a delayed manner to minimize the temperature and energy of the discharged alumina ceramic particles; during the test, the data collection of the performance test measurement points is checked to be normal; the temperature decay of the alumina ceramic particles exceeds the parameters required by the test and is less than 700°C, and the closed performance test is declared over, and the electric door for feeding alumina ceramic particles to the fluidized bed heat exchanger 8 is closed, and the end time t is recorded. 2 , t 2 -t 1 The time difference is the test period of the closed test.

[0075] The alumina ceramic particles in the cold storage tank 9 (volume 25 tons) were weighed and the average mass rate of the alumina ceramic particles feeding during the closed test was calculated. 2 ,t 1 The typical flue gas temperature measurement point data of the fluidized bed heat exchanger at 8 times is used to calculate the heat absorption of the casting material and include it in the correction calculation.

[0076] The fluidized bed open test is arranged separately. Before the test, under the guidance of a third party, the installation of the liquid carbon dioxide flow measurement device at the outlet of the booster pump is completed. The locations of other temporary performance measurement points are the same as those of the closed test; the solar mirror field is used again for heating and storage of 25 tons of alumina ceramic particles, and the temperature of alumina ceramic particles is greater than 700°C; the manual door for the open test discharge is closed, and the steam side of the carbon dioxide storage tank fluidized bed heat exchanger 8 is pressurized to 2.0Mpa; the liquid carbon dioxide booster pump and water bath furnace 10 are started to pressurize the carbon dioxide to 4.0MPa; the fluidized bed heat exchanger 8 is preheated to 300°C 2 days in advance; after the preheating of the fluidized bed heat exchanger 8 is completed, the switch valve at the inlet 85 of the high-temperature structural ceramic at the inlet of the fluidized bed heat exchanger 8 is opened. When the mobile storage tank with a capacity of 1.2 tons is full, the discharge pipe of the cold storage tank 9 (volume 25 tons) to the mobile storage tank (volume 1.2 tons) electric valve is closed, and the time t is recorded. 1 ; Gradually open the manual door for the carbon dioxide open test discharge, and control the carbon dioxide flow rate to 16.6 t / h; When the fluidized bed temperature gradually increases, reduce the carbon dioxide flow rate until the carbon dioxide outlet temperature reaches 550°C; The temperature decay of the alumina ceramic particles exceeds the parameters required by the test and is less than 700°C. The closed performance test is declared over, and the alumina ceramic particle feeding electric door of the fluidized bed heat exchanger 8 is closed, and the end time t is recorded 2 , t 2 -t 1 The time difference is the test period of the open test.

[0077] The alumina ceramic particles in the cold storage tank 9 (volume 25 tons) were weighed and the average mass rate of the alumina ceramic particles feeding during the closed test was calculated; 2 ,t1 The typical flue gas temperature measurement point data of the fluidized bed heat exchanger 8 at each moment is used to calculate the heat absorption of the casting material and include it in the correction calculation; the water volume from the booster pump outlet to the fluidized bed heat exchanger 8 outlet is calculated, and the mass of the sealed carbon dioxide gas before the test is calculated and included in the correction calculation.

[0078] The working principle of the fluidized bed heat exchanger 8 is that the solid alumina ceramic particles are lifted by the gas, so that the solid alumina ceramic particles present a state similar to that of a fluid. When the fluid passes through the alumina ceramic particle bed at a certain speed, as the flow rate increases, the alumina ceramic particle bed will go through three stages: fixed bed, fluidized bed and air flow transport. In the fluidized bed stage, the alumina ceramic particles are suspended in the fluid and move violently. This movement greatly improves the heat transfer and mass transfer efficiency between the alumina ceramic particles and the fluid. In the fluidized bed heat exchanger 8, the main heat transfer modes include convective heat transfer between the alumina ceramic particles and the fluid, contact heat transfer between the alumina ceramic particles and the wall, etc. For the convective heat transfer between the alumina ceramic particles and the fluid, due to the violent movement of the alumina ceramic particles, the contact surface with the fluid is continuously updated, so that the thermal boundary layer is continuously destroyed and updated, thereby strengthening the convective heat transfer process. In the fluidized bed, the alumina ceramic particles continuously hit the wall of the heat exchanger, and heat is transferred at the moment of contact. This contact heat transfer mode accounts for a considerable proportion in the entire heat transfer process, especially when there is a large difference between the wall temperature and the temperature of the alumina ceramic particles. The shell of the fluidized bed heat exchanger 8 is usually cylindrical. It needs to withstand a certain pressure and ensure that the internal fluidization process can proceed stably. The material of the shell is carbon steel selected according to the temperature, pressure, and fluid properties. The air distribution device is located at the bottom of the fluidized bed heat exchanger 8, and its function is to evenly distribute the fluidized medium into the alumina ceramic particle bed. A good air distribution device can ensure that the fluidization quality of the entire bed is uniform. Alumina ceramic particle material is an important component of the fluidized bed heat exchanger 8. The size, shape, density and other characteristics of the alumina ceramic particles will affect the fluidization quality and heat transfer performance.

[0079] In the fluidized bed heat exchanger 8, due to the violent movement of the alumina ceramic particles and good mixing performance, the temperature distribution in the entire bed layer is relatively uniform. This heat exchanger is a fluidized bed type, using a high-temperature solid of 700°C to heat supercritical carbon dioxide from 370°C to 550°C, and the fluidizing medium is high-pressure fluidized wind. The heat exchanger is installed on a steel frame located on the side of the solar absorption tower that has been built in the experimental power station. The steel frame is generally divided into five layers along the height direction. The top and bottom layers are high and low temperature alumina ceramic particle transfer layers, respectively. The fourth layer is mainly arranged with a heat storage tank 3, and the outlet of the heat storage tank 3 is connected to the high-temperature structural ceramic inlet 85 of the fluidized bed heat exchanger 8; the fluidized bed heat exchanger 8 is arranged on the third layer, and the whole is supported on the steel frame through the base of the fluidized bed heat exchanger 8; the second layer is mainly arranged with a low-temperature alumina ceramic particle storage tank. Under normal operation, after the alumina ceramic particles are heated to 700°C in the absorber 2 of the solar absorption tower, they are sent to the top layer of the steel frame through the high-temperature transfer device, injected into the hot storage tank 3, and enter the fluidized bed heat exchanger 8 through the outlet at the lower end of the hot storage tank 3. An adjusting baffle is provided at the outlet of the hot storage tank 3 to adjust the flow of alumina ceramic particles entering the heat exchanger to control the outlet temperature of the working medium of the fluidized bed heat exchanger 8. After the high-temperature alumina ceramic particles entering the fluidized bed heat exchanger 8 exchange heat with the heating surfaces arranged in the first, second, and third bins in succession, the temperature is reduced to about 500°C, and enter the cold storage tank 9 through the discharge pipe from the high-temperature structural ceramic outlet 86 located on the air distribution device of the fluidized bed heat exchanger 8. An adjusting baffle is also arranged on the high-temperature structural ceramic outlet 86 to control the material level in the heat exchanger by adjusting the discharge amount. After the alumina ceramic particles enter the cold storage tank 9, they enter the low-temperature transfer device through the outlet at the lower end of the cold storage tank 9 and are sent to the absorber 2 of the solar absorption tower for reheating. After the supercritical carbon dioxide system has the conditions for starting, supercritical carbon dioxide can be charged into the fluidized bed heat exchanger 8. After the supercritical carbon dioxide in the fluidized bed heat exchanger 8 tube has established a stable flow, the power of the electric heater 6 can be increased to increase the fluidizing air temperature and further heat the bed material. During the heating process, pay attention to control the outlet air temperature of the electric heater 6 not to exceed 500°C. During the heating process, the refractory material temperature measuring points of the shell of the fluidized bed heat exchanger 8 should always be closely monitored to ensure that the temperature of each measuring point is uniform, and the heating rate of the refractory material at each point does not exceed 80°C / hr. During the heating process, the fluidizing air volume and air pressure of each chamber should also be adjusted in time to make the fluidization of each chamber uniform and keep the pressure at the pressure balance point at zero. When the outlet air temperature of the fluidizing air reaches 100°C, open the fluidizing air recirculation pipeline to increase the outlet air temperature of the fluidizing fan 81. The purpose of using the fluidizing air heater 82 to heat the bed material is to increase the initial temperature of the bed material so that the heat exchanger can enter the designed test conditions as soon as possible. When the bed temperature of the fluidized bed heat exchanger 8 rises to above 450°C, or the fluidized air heater 82 has reached the maximum power, the bed temperature of the fluidized bed heat exchanger 8 no longer rises or rises slowly, the feed valve can be slowly opened, and the high-temperature alumina ceramic particles at 700°C begin to enter the fluidized bed heat exchanger 8.Adjust the valve opening of the high-temperature structural ceramic inlet 85 of the fluidized bed heat exchanger 8 to keep the material level of the fluidized bed heat exchanger 8 flush with the partition wall. When the high-temperature alumina ceramic particles establish a stable flow, the power of the electric heater 6 can be slowly reduced to increase the flow of high-temperature alumina ceramic particles. When the temperature of the first bin is basically equivalent to the inlet temperature of the alumina ceramic particles, the fluidized air heater 82 is turned off. According to the needs of the system or turbine 11 and the operation of the auxiliary machine, the fluidized bed heat exchanger 8 can continue to increase the flow of solid alumina ceramic particles and the flow of working fluid, and the load gradually increases until the load of the design condition. As the temperature of the alumina ceramic particles in the first, second and third bins of the fluidized bed heat exchanger 8 increases, the temperature of the supercritical carbon dioxide working fluid in the tube also gradually increases. At this time, attention should be paid to monitoring the outlet wall temperature measuring point of the heated surface. When the inlet pressure of the supercritical carbon dioxide is 15.0MPa, the maximum wall temperature of the tube does not exceed 650°C. When the temperature of the refractory material in the second bin rises to above 450°C and remains stable, the fluidized air heater 82 has reached the maximum power, and the bed temperature of the heat exchanger no longer rises or rises slowly, the feed valve can be slowly opened to start adding high-temperature alumina ceramic particles of not less than 600°C. When the temperature of the refractory material in the second bin rises to above 600°C and remains stable, start adding high-temperature alumina ceramic particles with a temperature of not less than 700°C. After the high-temperature alumina ceramic particles entering the fluidized bed heat exchanger 8 establish a stable flow, the power of the fluidized air heater 82 can be slowly reduced, and the flow rate of the high-temperature alumina ceramic particles can be increased. When the temperature of the first bin is basically equivalent to the inlet temperature of the alumina ceramic particles, the fluidized air heater 82 is turned off. After each bin establishes a normal material level, the valve opening on the outlet pipeline of the alumina ceramic particles of the heat exchanger is adjusted according to the bed pressure of each bin, the material level of the heat exchanger is kept flush with the partition wall, and the inlet and outlet balance of the solid alumina ceramic particles of the heat exchanger is maintained. When the heat exchanger is operating normally, the supercritical carbon dioxide flow rate and outlet temperature can meet the load requirements of the turbine 11.

[0080] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A solar thermal power generation system, characterized in that: include A heat collection system, wherein the heat collection system is used to collect sunlight; A heat exchange system, wherein the heat exchange system comprises a heat absorber and a fluidized bed heat exchanger, wherein the heat absorber can receive the sunlight collected by the heat collection system and convert it into heat, and can heat the high-temperature structural ceramics filled in the heat absorber, and the fluidized bed heat exchanger is connected to the heat absorber, and the fluidized bed heat exchanger can receive the high-temperature structural ceramics after being heated by the heat absorber, and the high-temperature structural ceramics exchange heat with the supercritical carbon dioxide in the fluidized bed heat exchanger, wherein the fluidized bed heat exchanger comprises an air distribution device and a bed layer, wherein the bed layer is used to carry the high-temperature structural ceramics, and the air distribution device is arranged below the bed layer, and the air distribution device is used for ventilation to make the high-temperature structural ceramics on the bed layer present a fluidized state; A conversion system is connected to the fluidized bed heat exchanger, capable of receiving supercritical carbon dioxide after heat exchange in the fluidized bed heat exchanger, and converting the heat energy carried by the supercritical carbon dioxide into electrical energy.

2. The solar thermal power generation system according to claim 1, characterized in that: The shell of the fluidized bed heat exchanger is cylindrical, the air distribution device and the bed layer are arranged inside the shell, the fluidized bed heat exchanger is provided with a supercritical carbon dioxide circulation pipeline and a high-temperature ceramic circulation cavity, the supercritical carbon dioxide circulation pipeline is arranged in a serpentine shape and fixed in the high-temperature ceramic circulation cavity, the supercritical carbon dioxide circulation pipeline is provided with a supercritical carbon dioxide inlet and a supercritical carbon dioxide outlet, the high-temperature ceramic circulation cavity is provided with a high-temperature structural ceramic inlet and a high-temperature structural ceramic outlet, the supercritical carbon dioxide inlet is arranged on one side of the fluidized bed heat exchanger, the high-temperature structural ceramic inlet is arranged on the other side of the fluidized bed heat exchanger, the supercritical carbon dioxide outlet is arranged at the top of the high-temperature structural ceramic inlet side, and the high-temperature structural ceramic outlet is arranged at the bottom of the supercritical carbon dioxide inlet side.

3. The solar thermal power generation system according to claim 1, characterized in that: The fluidized bed heat exchanger further comprises a fluidizing fan and a fluidizing air heater, wherein the air inlet end of the fluidizing air heater is connected to the air outlet of the fluidizing fan, and the air outlet end of the fluidizing air heater is connected to the air distribution device.

4. The solar thermal power generation system according to claim 1, characterized in that: The heat collection system is a heliostat field composed of a plurality of heliostats.

5. The solar thermal power generation system according to claim 2, characterized in that: The heat exchange system also includes a hot storage tank and a cold storage tank. The feed port of the hot storage tank is connected to the discharge port of the heat absorber, and the discharge port of the hot storage tank is connected to the inlet of the high-temperature structural ceramics. The hot storage tank is used to store the high-temperature structural ceramics that have been heated and transfer them to the fluidized bed heat exchanger. The feed port of the cold storage tank is connected to the outlet of the high-temperature structural ceramics, and the discharge port of the cold storage tank is connected to the feed port of the heat absorber. The cold storage tank is used to store the high-temperature structural ceramics after heat exchange and transfer them to the heater.

6. The solar thermal power generation system according to claim 5, characterized in that: It also includes an electric heater, which is arranged on a pipeline connecting the heat storage tank and the fluidized bed heat exchanger, and can heat high-temperature structural ceramics whose temperature does not meet the standard. The electric heater is powered by photovoltaic power, wind power and off-peak electricity.

7. The solar thermal power generation system according to claim 2, characterized in that: The conversion system comprises a turbine and a generator, wherein the turbine is connected to the supercritical carbon dioxide outlet, and the output end of the turbine is connected to the generator.

8. The solar thermal power generation system according to claim 7, characterized in that: It also includes a circulation system, which includes a heat regenerator, a condenser and a compressor connected in sequence. The heat regenerator is connected to the turbine and can receive and process the supercritical carbon dioxide after the work is completed. The condenser is used to condense the treated supercritical carbon dioxide. The compressor is connected to the supercritical carbon dioxide inlet and is driven by an electric motor to transport the condensed supercritical carbon dioxide to the supercritical carbon dioxide inlet.

9. The solar thermal power generation system according to claim 8, characterized in that: It also includes a water bath furnace, which is arranged on the connecting pipeline between the compressor and the fluidized bed heat exchanger, and is used to perform constant temperature treatment on the supercritical carbon dioxide.

10. The solar thermal power generation system according to claim 1, characterized in that: The high temperature structural ceramics are alumina ceramic particles.

Images