Biomass afterburning tower type photo-thermal power generation system and operation method

Abstract

The application discloses a kind of biomass afterburning's tower type photo-thermal power generation system and operating method, belong to photo-thermal power generation technical field, including molten salt loop, water loop and afterburning loop;Afterburning loop includes biomass afterburning system, molten salt heater, superheated steam heater and reheat steam heater and feedwater heater;High-temperature flue gas formed in biomass afterburning system respectively after molten salt heater, superheated steam heater and reheat steam heater and molten salt loop's molten salt, superheated steam and reheat steam in water loop heat exchange, into medium-temperature flue gas;Medium-temperature flue gas is heated with feedwater in feedwater heater and becomes low-temperature flue gas, and is used for biomass upgrading.The application is suitable for weather fluctuation sensitivity higher tower type system, and the heat generated in afterburning loop is used to heat molten salt in molten salt loop and superheated steam and reheat steam in water loop, so as to ensure the heat storage in high-temperature molten salt tank, improve steam turbine efficiency, and then reduce energy waste and pollutant emission.

Description

Technical Field

[0001] This invention belongs to the field of concentrated solar power (CSP) technology, specifically relating to a tower CSP system with biomass combustion and its operation method. Background Technology

[0002] The installed capacity of renewable energy sources, primarily wind and solar power, is rapidly increasing. However, the volatility of wind and solar power output poses a severe challenge to the supply-demand balance and stability of the power system. Solar thermal power generation, typically equipped with molten salt thermal storage systems operating for more than 6 hours, can achieve continuous and stable power output, making it a very promising renewable energy power generation technology. Currently, the installed capacity nationwide is 838MW, with 3300MW under construction.

[0003] The heat collection process in tower-type concentrated solar power (CSP) is significantly affected by weather conditions, requiring frequent adjustments to power generation. These adjustments are typically achieved by altering the flow rates of molten salt and steam. Specifically, insufficient sunlight severely reduces the heat collection capacity of the system, shortening power generation duration and impacting short-term and even long-term power generation strategies. Furthermore, when the heat storage capacity of the high-temperature molten salt tank is insufficient to support the turbine's prolonged rated power operation, power output must be reduced to maintain continuous unit operation, thereby lowering power generation efficiency. Therefore, these adjustments are accompanied by changes in the heat transfer efficiency of the steam generation system, leading to fluctuations in the turbine inlet steam temperature. This, in turn, causes thermal stress fatigue in the turbine equipment, shortening its service life.

[0004] Under low direct normal irradiance (DNI) conditions, it is also necessary to reduce the flow rate of the cryogenic molten salt pumped into the receiver to ensure a constant molten salt temperature at the receiver outlet (approximately 560°C). However, reducing the molten salt flow rate will cause a significant decrease in receiver efficiency, increase heat loss, and thus reduce the total heat collection.

[0005] Furthermore, current tower-type concentrated solar power (CSP) systems commonly use binary molten nitrate salts (60% NaNO3 + 40% KNO3) as the heat transfer and storage medium. Its decomposition temperature is around 600℃, and industrial designs typically limit the operating temperature below 565℃ to avoid changes in physical properties caused by molten salt decomposition. Therefore, the superheated and reheated steam temperatures in tower-type CSP plants are usually between 540-560℃, making it difficult to further increase the steam temperature and limiting the improvement of turbine efficiency.

[0006] Biomass, with its carbon-neutral and low-pollution characteristics, is a promising renewable energy source. Combining biomass energy with solar energy for power generation or combined heat and power (CHP) can improve the efficiency and stability of the coupled system. However, currently, there is a lack of technologies and methods for combining biomass energy with tower-type concentrated solar power (CSP) systems. Summary of the Invention

[0007] In view of this, the present invention provides a tower solar thermal power generation system and operation method based on biomass afterburning, which is suitable for tower systems that are highly sensitive to weather fluctuations. The system heats the molten salt in the molten salt circuit and the superheated steam and reheated steam in the water circuit by generating heat in the biomass afterburning circuit, thereby ensuring the heat storage in the high-temperature molten salt tank, improving the efficiency of the steam turbine, and thus reducing energy waste and pollutant emissions.

[0008] This invention is achieved through the following technical solution: A tower-type solar thermal power generation system with biomass afterburning includes: a molten salt circuit, a water circuit, and an afterburning circuit using biomass as fuel; The afterburning circuit includes: a biomass afterburning system, a molten salt heater, a superheated steam heater, a reheated steam heater, and a feedwater heater; The biomass afterburning system uses biomass as fuel and generates high-temperature flue gas in the afterburning circuit. The high-temperature flue gas is divided into three streams. The first stream of high-temperature flue gas exchanges heat with the molten salt in the pipeline between the heat absorption tower and the high-temperature molten salt tank in the molten salt circuit through the molten salt heater. The second stream of high-temperature flue gas exchanges heat with the superheated steam in the pipeline between the water side of the superheater and the high-pressure cylinder of the turbine in the water circuit through the superheated steam heater. The third stream of high-temperature flue gas exchanges heat with the reheated steam in the pipeline between the water side of the reheater and the intermediate-pressure cylinder of the turbine in the water circuit through the reheated steam heater. Finally, they are combined into one stream to form medium-temperature flue gas. The medium-temperature flue gas undergoes heat exchange with the feedwater in the water circuit through the feedwater heater, and forms low-temperature flue gas; The low-temperature flue gas is returned to the biomass combustion system for biomass upgrading.

[0009] Furthermore, the molten salt heater includes a flue gas side and a molten salt side, wherein the inlet of the flue gas side is connected to the biomass supplementary combustion system, and the molten salt side is located on the pipeline between the heat absorption tower and the high-temperature molten salt tank in the molten salt circuit. The superheated steam heater includes a flue gas side and a water side. The inlet of the flue gas side is connected to the biomass combustion system, and the water side is located on the pipeline between the water side of the superheater and the high-pressure cylinder of the steam turbine in the water circuit. The reheat steam heater includes a flue gas side and a water side. The inlet of the flue gas side is connected to the biomass combustion system, and the water side is installed on the pipeline between the reheater and the intermediate pressure cylinder of the steam turbine in the water circuit. The water supply heater includes: a flue gas side and a water side; The flue gas outlets of the molten salt heater, the superheated steam heater, and the reheated steam heater are combined into one and connected to the flue gas inlet of the feedwater heater. The flue gas outlet of the feedwater heater is connected to the biomass combustion system. The water side of the molten salt heater is located on the pipeline between the water side of the preheater and the high-pressure heater in the water circuit. When the high-temperature flue gas, which is divided into three streams, passes through the flue gas side of the molten salt heater, the superheated steam heater, and the reheated steam heater, it exchanges heat with the molten salt side of the molten salt heater, the water side of the superheated steam heater, and the water side of the reheated steam heater, respectively. The medium-temperature flue gas passes through the flue gas side of the feedwater heater and exchanges heat with the water side of the feedwater heater.

[0010] Furthermore, the afterburning circuit also includes: a second valve, a third valve, a fourth valve, a fifth valve, and a sixth valve; The second valve is installed on the pipeline between the heat absorption tower and the inlet on the molten salt side of the molten salt heater; The third valve is installed on the pipeline between the outlet of the molten salt heater on the molten salt side and the high-temperature molten salt tank; The fourth valve is installed on the pipeline between the biomass afterburning system and the flue gas inlet of the molten salt heater; The fifth valve is installed on the pipeline between the biomass afterburning system and the flue gas inlet of the superheated steam heater; The sixth valve is installed on the pipeline between the biomass afterburning system and the flue gas inlet of the reheat steam heater; The molten salt circuit also includes: a first valve, which is installed on the pipeline between the heat absorption tower and the high-temperature molten salt tank, and is connected in parallel with the second valve, the molten salt heater and the third valve.

[0011] Furthermore, the biomass afterburning system includes: pretreatment equipment, a roasted biomass storage facility, a combustion furnace, and exhaust gas treatment equipment; The pretreatment equipment is used to bake and improve the quality of biomass, and its outlet is connected to the inlet of the baked biomass storage warehouse. The exhaust gas treatment equipment is connected to the exhaust port of the pretreatment equipment; The outlet of the roasting biomass storage tank is connected to the inlet of the combustion furnace; The combustion furnace is used to burn biomass; the outlet of the high-temperature flue gas from the combustion furnace is divided into three streams, which are respectively connected to the fourth valve, the fifth valve and the sixth valve; The outlet of the flue gas side of the water heater is connected to a pretreatment device, so that the low-temperature flue gas can be used for biomass upgrading.

[0012] Furthermore, the pretreatment equipment includes: a first spiral feed inlet, a first spiral discharge outlet, a wind box, a baking layer, a drying layer, and a new material layer; The air box, baking layer, drying layer and fresh material layer are arranged and connected from bottom to top; the first spiral feed inlet is located on the fresh material layer; the first spiral discharge outlet is located at the bottom of the baking layer and is used to connect to the inlet of the baking biomass storage tank; the inlet of the air box is connected to the flue gas duct of the water heater outlet.

[0013] Furthermore, the combustion furnace includes: a second spiral feed inlet, an air inlet, a make-up air inlet, an ash hopper, a fuel bed, and a furnace chamber; The ash hopper, fuel bed, and furnace are arranged sequentially from bottom to top and are interconnected. The furnace exhaust port is divided into three streams, which are respectively connected to the flue gas side of the molten salt heater, the superheated steam heater, and the reheated steam heater. The second spiral feed port is located on the fuel bed. The air inlet is located on the ash hopper, and the make-up air inlet is located on the furnace.

[0014] An operation method for a biomass-assisted combustion tower solar thermal power generation system, based on the aforementioned tower solar thermal power generation system, includes the following steps: S1: When the power generation demand of the tower solar thermal power generation system changes, adjust the feedwater flow rate into the water circuit and the high-temperature molten salt flow rate in the molten salt circuit; measure the superheated steam flow rate at the water-side outlet of the superheater in the water circuit at this time. and temperature The flow rate of reheat steam at the water-side outlet of the reheater and temperature ; When illumination conditions change, the flow rate of molten salt entering the absorber of the heat exchanger is adjusted synchronously; the flow rate of high-temperature molten salt at the outlet of the absorber in the molten salt circuit is measured at this time. and temperature And at this time The temperature above the starting temperature at which molten salt condensation and freezing blockage occur inside the receiver. And less than the storage temperature of the high-temperature molten salt in the high-temperature molten salt tank. ; S2: When the power generation demand of the tower solar thermal power generation system changes, set the steam temperature at the inlet of the high-pressure cylinder and the steam temperature at the inlet of the intermediate-pressure cylinder of the turbine. and through , , , , and the specific heat capacity of superheated steam and density Specific heat capacity of reheated steam and density Calculate the amount of heat required for a superheated steam heater to heat superheated steam. The heat required by the reheat steam heater to heat the reheat steam and the total heat required to heat the steam ; When lighting conditions change, through , , and the specific heat capacity of high-temperature molten salt and density Calculate the heat required to heat high-temperature molten salt ; Calculate the total heat required when both power generation and sunlight conditions change. ; S3: When the power generation demand of the tower solar thermal power generation system changes, the heat exchange and performance curves of the superheated steam heater and the reheated steam heater are used, combined with the physical property parameters of the high-temperature flue gas flowing out of the combustion furnace, to obtain... Required high-temperature flue gas flow rate and Required high-temperature flue gas flow rate ;Measure the temperature of high-temperature flue gas and ambient temperature ;pass And calculate the total flow rate of the required high-temperature flue gas. ; When illumination conditions change, the required flow rate of high-temperature flue gas is obtained by combining the heat exchange and performance curves of the molten salt heater with the physical properties of the high-temperature flue gas flowing out of the combustion furnace. Measure the temperature of high-temperature flue gas and ambient temperature ;at this time, That is, the total flow rate of the required high-temperature flue gas. ; When both power generation and sunlight conditions change, through , and Calculate total flow ; and through Specific heat capacity of high-temperature flue gas Density of high-temperature flue gas as well as Calculate the total heat released by burning biomass for baking. Then, by examining the calorific value of the roasted biomass... Calculate the required mass of biomass fuel for baking. ; S4: Open or close the valve to allow heat exchange between the afterburning circuit and the molten salt circuit, and between the afterburning circuit and the water circuit; S5: The temperature of the intermediate-temperature flue gas after mixing the flue gas flowing from the flue gas side of the molten salt heater, the flue gas side of the superheated steam heater, and the flue gas side of the reheated steam heater is... ; Based on the water supply in the water circuit Specific heat capacity of water supply in water circuit and density Calculate the amount of heat required to heat the high-pressure heater outlet temperature to the set feedwater temperature. ; Based on the performance curve of the feedwater heater and the flue gas inlet of the feedwater heater, combined with , Heat transfer efficiency between flue gas side and water side in feedwater heater Specific heat capacity of intermediate temperature flue gas Density of intermediate-temperature flue gas And the temperature of the flue gas used for baking and quality improvement, the temperature of the medium-temperature flue gas. Calculate the required flow rate of the intermediate-temperature flue gas. ; when hour, The medium-temperature flue gas is introduced into the flue gas side of the feedwater heater, and after heating the feedwater, it is introduced into the biomass afterburning system; the excess flue gas after heating the feedwater is diluted and cooled by nitrogen and then introduced into the biomass afterburning system. when At the same time, all medium-temperature flue gas is introduced into the flue gas side of the feedwater heater to heat the feedwater and then into the biomass refueling system; simultaneously, the pump power of the high-temperature molten salt in the high-temperature molten salt tank is increased, thereby increasing the flow rate of molten salt entering the superheater and reheater.

[0015] Furthermore, in step S2: ; ; ; ; .

[0016] Furthermore, in step S3: ; When the power output of a tower-type concentrated solar power (CSP) system changes: ; When lighting conditions change: ; When both power generation and sunlight conditions change: ; .

[0017] Furthermore, in step S5: ; Excess smoke volume is .

[0018] Beneficial effects: (1) The present invention provides a biomass-fueled tower solar thermal power generation system that uses biomass as fuel to reduce carbon emissions during the operation of the power plant. The fueling circuit includes a biomass fueling system, a molten salt heater, a superheated steam heater, and a reheated steam heater. The molten salt is heated by the high-temperature flue gas generated by biomass combustion. Even when there is insufficient light or fluctuations in radiation intensity, the temperature of the molten salt can be kept stable without significantly reducing the flow rate of the molten salt entering the receiver, thereby improving the receiver efficiency and the total heat collection. The high-temperature flue gas is used to heat the superheated steam and reheated steam. Compared with existing tower solar thermal power plants, the steam temperature at the turbine inlet can be raised to above 565°C, improving the turbine efficiency and extending the service life of the equipment. Even when the light conditions and power generation frequently change, the system can maintain stability and continuity. Combined with meteorological forecasts, effective power generation strategies can be formulated in advance. The feedwater heater preheats the feedwater, reducing the flow rate of molten salt pumped into the steam generation system, increasing the molten salt heat storage time, and reducing the risk of molten salt freezing at the preheater outlet. In addition, the solar thermal power generation system significantly improves the efficiency and economy of the coupled system by utilizing high-temperature flue gas, medium-temperature flue gas and low-temperature flue gas in stages. Compared with directly using external heat sources for biomass fuel upgrading, the system structure is simpler and the operating cost is lower.

[0019] (2) A biomass supplementary combustion tower solar thermal power generation system of the present invention further includes a supplementary combustion circuit including a second valve, a third valve, a fourth valve, a fifth valve and a sixth valve; by adjusting the first valve, the second valve, the third valve and the fourth valve, the flow rate of high temperature flue gas and molten salt can be quickly adjusted to realize heat exchange between the supplementary combustion circuit and the molten salt circuit, so that the high temperature flue gas generated by combustion can heat the molten salt at the outlet of the absorber. Even under insufficient light conditions, the molten salt temperature at the inlet of the high temperature molten salt tank can be maintained at the rated value. It is only necessary to ensure that the molten salt does not condense and freeze in the absorber, without significantly reducing the flow rate of molten salt pumped into the absorber, thereby reducing the heat collection loss caused by the adjustment of the molten salt flow rate in the past, and thus improving the absorber efficiency and the total heat collection in cloudy weather or insufficient light conditions. By adjusting the fifth and sixth valves, the flow rate of high-temperature flue gas entering the superheated steam heater and the reheated steam heater can be quickly regulated, and heat exchange between the combustion circuit and the water circuit can be realized. This allows the high-temperature flue gas generated by combustion to heat the steam temperature at the water-side outlet of the superheater and the water-side outlet of the reheater, thus maintaining a stable temperature. This breaks through the 565°C temperature limit of molten salt in existing solar thermal power plants, improves the parameters of main steam and reheat steam, and increases power generation efficiency.

[0020] (3) A tower-type solar thermal power generation system for biomass supplementary combustion of the present invention includes: a pretreatment device, a roasted biomass storage tank and a combustion furnace. The pretreatment device roasts and upgrades the biomass, which can remove chlorine from the biomass, effectively reduce pollutant emissions during the supplementary combustion process and alleviate slagging on the surface of the flue heat exchanger. The roasted and upgraded biomass can be stored in the roasted biomass storage tank, thereby improving combustion efficiency. The outlet of the flue gas side of the feedwater heater is connected to the pretreatment device, so that the low-temperature flue gas can be used for biomass upgrading. Since the solar thermal power generation area is often dry, the biomass fuel treated by natural drying methods such as sun drying has low water content. Therefore, less energy is required to dry the biomass. The waste heat of the flue gas can be used to remove internal water or to roast the biomass, and can also avoid the high temperature of the flue gas from causing cracking of the biomass.

[0021] (4) In a tower-type solar thermal power generation system for biomass supplementary combustion of the present invention, in the pretreatment equipment, the wind box, baking layer, drying layer and new material layer are arranged and connected from bottom to top; the first spiral feed port is set on the new material layer; the first spiral discharge port is set on the drying layer and is used to connect to the inlet of the baking biomass storage warehouse; the wind box inlet is connected to the main stream of the biomass supplementary combustion system, which can effectively utilize the preheating of the high temperature flue gas after heating steam and molten salt, thereby improving the utilization rate of thermal energy; the exhaust gas treatment equipment is connected to the exhaust port of the pretreatment equipment, which can control the sulfur and nitrogen pollution generated during baking and upgrading.

[0022] (5) A tower-type solar thermal power generation system for biomass supplementary combustion of the present invention includes a combustion furnace comprising an air inlet and a supplementary air inlet, which can supply air in stages to improve the biomass combustion rate; in addition, by adjusting the air supply volume of the air inlet and the supplementary air inlet, the oxygen content in the flue gas can be controlled to prevent the oxygen content in the flue gas returned to the pretreatment equipment from being too high, which would cause the biomass to oxidize prematurely during the quality improvement process, thereby ensuring the quality of the biomass.

[0023] (6) A biomass supplementary combustion tower solar thermal power generation system and operation method of the present invention, when the power generation demand of the tower solar thermal power generation system changes, the method can change the heat exchange and outlet steam volume of the tower solar thermal power generation system by adjusting the steam flow rate and molten salt capacity, and adjust the biomass feed rate and air volume in the supplementary combustion system according to the steam temperature at the outlet of the superheater and reheater, thereby maintaining the turbine inlet steam temperature, improving the service life of the turbine, and improving the power generation efficiency; when the illumination conditions change, the biomass feed rate and air volume in the supplementary combustion system can be adjusted according to the molten salt flow rate and outlet temperature of the absorber, thereby maintaining the molten salt temperature at the inlet of the high-temperature molten salt tank at the rated value, improving the heat absorption efficiency of the absorber and the total heat collection when the illumination is insufficient. Attached Figure Description

[0024] Figure 1 A schematic diagram of the tower-type solar thermal power generation system for biomass supplementary combustion according to the present invention; Figure 2 This is a schematic diagram of the biomass afterburning system of the present invention; Figure 3 This is a schematic diagram of the biomass fuel energy cascade utilization of the present invention; Figure 4 A flowchart illustrating the operation method of the biomass-assisted combustion tower solar thermal power generation system of the present invention; Among them, 1-Heat absorber, 2-High-temperature molten salt tank, 3-Low-temperature molten salt tank, 4-Preheater, 5-Evaporator, 6-Superheater, 7-Reheater, 8-Feedwater heater, 9-High-pressure heater, 10-Feedwater pump, 11-Deaerator, 12-Low-pressure heater, 13-Condenser, 14-Generator, 15-Steam turbine, 16-Reheat steam heater, 17-Superheat steam heater, 18-Combustion furnace, 19-Roasted biomass storage, 20-Pretreatment equipment, 21-Tail gas treatment equipment, 22-Molten salt heater, 23-Then 24-First valve, 25-Third valve, 26-Fourth valve, 27-Fifth valve, 28-Sixth valve, 29-Inlet on the flue gas side of the feedwater heater, 30-Outlet on the flue gas side of the feedwater heater, 181-Second spiral feed inlet, 182-Air inlet, 183-Make-up air inlet, 184-Ash hopper, 185-Fuel bed, 186-Furnace, 201-First spiral feed inlet, 202-First spiral discharge outlet, 203-Wind box, 204-Baking layer, 205-Drying layer, 206-New material layer. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] Example 1: This embodiment provides a tower-type solar thermal power generation system with biomass afterburning, such as Figure 1 As shown, it includes: a molten salt circuit, a water circuit, and a biomass-fueled afterburner circuit (hereinafter referred to as the afterburner circuit). The molten salt circuit includes: an absorber tower 1, a high-temperature molten salt tank 2, the molten salt side of the superheater 6, the molten salt side of the reheater 7, the molten salt side of the evaporator 5, the molten salt side of the preheater 4, a low-temperature molten salt tank 3, and a first valve 24. The outlet of the heat absorber 1 is connected to the inlet of the high-temperature molten salt tank 2. The outlet of the high-temperature molten salt tank 2 is divided into two streams, which are respectively connected to the inlet of the molten salt side of the superheater 6 and the inlet of the molten salt side of the reheater 7. The outlet of the molten salt side of the superheater 6 and the outlet of the molten salt side of the reheater 7 are combined into one stream, which is sequentially connected to the molten salt side of the evaporator 5, the molten salt side of the preheater 4, and the inlet of the low-temperature molten salt tank 3. The outlet of the low-temperature molten salt tank 3 is connected to the inlet of the heat absorber 1. The first valve 24 is installed on the pipeline between the heat absorber 1 and the high-temperature molten salt tank 2 to control the flow of molten salt. The water circuit includes: the water side of the preheater 4, the water side of the evaporator 5, the water side of the superheater 6, the steam turbine 15, the water side of the reheater 7, the generator 14, the condenser 13, the low-pressure heater 12, the deaerator 11, the feedwater pump 10, and the high-pressure heater 9. The outlet of the high-pressure heater 9 is sequentially connected to the water side of the preheater 4, the water side of the evaporator 5, the water side of the superheater 6, and the inlet of the high-pressure cylinder of the turbine 15; the outlet of the high-pressure cylinder of the turbine 15 is sequentially connected to the water side of the reheater 7 and the inlet of the intermediate-pressure cylinder of the turbine 15; the outlet of the intermediate-pressure cylinder is sequentially connected to the condenser 13, the low-pressure heater 12, the deaerator 11, the feedwater pump 10, and the inlet of the high-pressure heater 9. The water circulation loop and the molten salt circulation loop are coupled through preheater 4, evaporator 5, superheater 6 and reheater 7. Specifically, water heated by high-pressure heater 9 enters the water side of preheater 4; the water on the water side of preheater 4 is preheated by the heat from the molten salt side of preheater 4; the preheated water enters the water side of evaporator 5 and is heated by the heat from the molten salt side of evaporator 5 to evaporate into steam; the steam enters the water side of superheater 6 and is heated by the heat from the molten salt side of superheater 6 to superheated steam; the steam after the high-pressure cylinder of turbine 15 expands and does work enters the water side of reheater 7 and is heated by the heat from the molten salt side of reheater 7 to form reheated steam; the reheated steam expands and does work through the intermediate-pressure cylinder and low-pressure cylinder of turbine 15, and then passes through condenser 13, low-pressure heater 12, deaerator 11 and feedwater pump 10 in sequence before returning to high-pressure heater 9. The afterburning circuit includes: a biomass afterburning system, a feedwater heater 8, a molten salt heater 22, a superheated steam heater 17, a reheated steam heater 16, a fourth valve 26, a fifth valve 27, and a sixth valve 28; The biomass afterburning system includes: pretreatment equipment 20, roasted biomass storage 19, and combustion furnace 18; The pretreatment equipment 20 is used for drying and baking biomass, thereby improving the quality of biomass fuel; the upgraded biomass is then converted into baked biomass. The baking biomass storage 19 is used to store the roasted and upgraded biomass, which is then transferred to the combustion furnace 18 as needed. Combustion furnace 18 is used to burn biomass and generate high-temperature flue gas (in this embodiment, the temperature of the high-temperature flue gas is greater than 565°C). Molten salt heater 22 is used to heat the molten salt at the inlet of the high-temperature molten salt tank in the molten salt circuit, including: flue gas side and molten salt side; Superheated steam heater 17 is used to heat the superheated steam flowing out of the water side outlet of superheater 6 in the water circuit, including: flue gas side and water side: The reheat steam heater 16 is used to heat the reheat steam flowing out of the water side outlet of the reheater 7 in the water circuit, including: flue gas side and water side; The outlet of the pretreatment equipment 20 is connected to the inlet of the roasting biomass storage silo 19, and the outlet of the biomass storage silo 19 is connected to the inlet of the combustion furnace 18. The flue gas outlet of the combustion furnace 18 is divided into three streams: the first stream is connected to the flue gas inlet of the molten salt heater 22, the second stream is connected to the flue gas inlet of the superheated steam heater 17, and the third stream is connected to the flue gas inlet of the reheated steam heater 16. The flue gas outlet of the molten salt heater 22, the outlet of the superheated steam heater 17, and the outlet of the reheated steam heater 16 are combined into a medium-temperature flue gas pipeline, which is connected to the flue gas inlet 29 of the feedwater heater. The flue gas outlet of the feedwater heater 8 is connected to the air inlet of the pretreatment equipment 20. The fourth valve 26 is installed on the pipeline between the flue gas outlet of the combustion furnace 18 and the flue gas inlet of the molten salt heater 22; the fifth valve 27 is installed on the pipeline between the flue gas outlet of the combustion furnace 18 and the flue gas inlet of the superheated steam heater 17; the sixth valve 28 is installed on the pipeline between the flue gas outlet of the combustion furnace 18 and the flue gas inlet of the reheat steam heater 16; the second valve 23 is installed on the pipeline between the heat absorption tower 1 and the molten salt inlet of the molten salt heater 22; the third valve 25 is installed on the pipeline between the molten salt outlet of the molten salt heater 22 and the high-temperature molten salt tank 2; the second valve 23, the molten salt heater 22, and the third valve 25 are connected in parallel with the first valve 24. The molten salt side of the molten salt heater 22 is located on the pipeline between the outlet of the heat absorption tower 1 and the inlet of the high-temperature molten salt tank 2, and is connected in parallel with the first valve 24. When weather conditions change and the heat collection of the heat absorption tower 1 is insufficient, the first valve 24 is closed and the second valve 23, the third valve 25 and the fourth valve 26 are opened, so that the high-temperature flue gas passes through the flue gas side of the molten salt heater 22 and transfers heat to the molten salt on the molten salt side of the molten salt heater 22, thereby increasing the temperature of the molten salt at the inlet of the high-temperature molten salt tank 2, thereby ensuring the stability of the molten salt temperature in the high-temperature molten salt tank 2. The water side of the superheated steam heater 17 is located on the pipeline between the outlet of the water side of the superheater 6 and the inlet of the high-pressure cylinder of the steam turbine 15. When the temperature of the superheated steam at the inlet of the high-pressure cylinder is unstable or lower than the required superheated steam temperature, the fifth valve 27 is opened, so that the high-temperature flue gas flowing out of the combustion furnace 18 passes through the flue gas side of the superheated steam heater 17 and transfers heat to the superheated steam on the water side of the superheated steam heater 17, thereby increasing the parameters (such as temperature) of the superheated steam at the inlet of the high-pressure cylinder and maintaining a stable temperature, thereby ensuring the efficiency of the steam turbine 15. The water side of the reheat steam heater 16 is located on the pipeline between the outlet of the water side of the reheater 7 and the inlet of the intermediate pressure cylinder of the steam turbine 15. When the temperature of the reheat steam at the inlet of the intermediate pressure cylinder is unstable or the temperature of the reheat steam is lower than the required temperature, the sixth valve 28 is opened, so that the high temperature flue gas passes through the flue gas side of the reheat steam heater 16 and transfers heat to the reheat steam on the water side of the reheat steam heater 16, thereby improving the parameters (such as temperature) of the reheat steam at the inlet of the intermediate pressure cylinder and maintaining a stable temperature, thereby ensuring the efficiency of the steam turbine 15. The water side of the feedwater heater 8 is located on the pipeline between the water side inlet of the preheater 4 and the water side outlet of the high-pressure heater 9. The flue gas side outlets of the molten salt heater 22, the superheated steam heater 17, and the reheated steam heater 16 are combined into one and connected to the flue gas side inlet 29 of the feedwater heater 8. This allows the heat from the flue gas (hereinafter described as medium-temperature flue gas, with a temperature greater than or equal to 300°C and less than 565°C) flowing out of the molten salt heater 22, the superheated steam heater 17, and the reheated steam heater 16 to preheat the water before it enters the preheater 4. After passing through the feedwater heater 8, the medium-temperature flue gas becomes low-temperature flue gas (below 300°C in this embodiment). The low-temperature flue gas enters the pretreatment equipment 20 for upgrading the biomass. The feedwater heater 8 can utilize the heat of the medium-temperature flue gas and avoids the biomass thermal decomposition caused by the high temperature when the medium-temperature flue gas directly enters the pretreatment equipment 20.

[0027] Example 2: This embodiment provides a tower-type solar thermal power generation system for biomass supplementary combustion. Based on Embodiment 1, this tower-type solar thermal power generation system also provides the specific structure of the pretreatment equipment 20 and the combustion furnace 18. like Figure 2 As shown, the pretreatment equipment 20 includes: a first spiral feed inlet 201, a first spiral discharge outlet 202, a wind box 203, a baking layer 204, a drying layer 205, and a new material layer 206; The drying layer 205 is used to remove the inherent moisture in the biomass and the small amount of external moisture absorbed during long-term storage. The baking layer 204 is used to reduce the oxygen content in biomass, thereby increasing the carbon content, improving fuel quality, and increasing the combustion temperature, thereby improving the heat exchange efficiency between high-temperature flue gas and molten salt. During the baking process, a large amount of chlorine and sulfur elements can be released, thereby reducing the release of alkali metal compounds during biomass combustion, and thus alleviating the problem of ash accumulation and slagging in the furnace and heat exchange surfaces. The air box 203 is used to blow the low-temperature flue gas flowing out of the outlet 30 on the flue gas side of the feedwater heater into the pretreatment equipment 20; The air box 203, baking layer 204, drying layer 205 and fresh material layer 206 are arranged and connected from bottom to top; the first spiral feed port 201 is set on the fresh material layer 206, and the first spiral discharge port 202 is set at the bottom of the drying layer 204; the inlet of the air box 203 is connected to the outlet 30 on the flue gas side of the water heater. The low-temperature flue gas flowing out from the water heater 8 enters the baking layer 204 and the drying layer 205 sequentially through the wind box 203; under the action of the low-temperature flue gas, the biomass in the baking layer 204 is heated to 200-300℃, and the biomass in the drying layer 205 is heated to 100-150℃, thereby realizing the baking and drying of biomass to improve its quality. Biomass enters the new material layer 206 through the first spiral feed port 201, and is dried and baked in sequence through the drying layer 205 and the baking layer 204. After baking, the biomass enters the baked biomass storage 19 through the first spiral discharge port 202. The combustion furnace 18 includes: a second spiral feed inlet 181, an air inlet 182, a make-up air inlet 183, an ash hopper 184, a fuel bed 185, and a furnace chamber 186; Fuel bed 185 is used for biomass combustion; The furnace 186 is used for the complete combustion of combustibles released during the combustion of biomass, and the generated high-temperature flue gas is discharged through the exhaust port on the furnace 186. Air inlet 182 is used to connect to the combustion fan, thereby providing the air required for biomass combustion; Air inlet 183 is used to connect to combustion air fan, thereby supplying air to furnace 186 so that combustibles can be fully burned; Ash hopper 184 is used to collect and discharge the ash residue produced after biomass is burned out; The ash hopper 184, fuel bed 185, and furnace 186 are arranged sequentially from bottom to top and are interconnected; the exhaust port of the furnace 186 is divided into three streams, which are respectively connected to the fourth valve 26, the fifth valve 27, and the sixth valve 28; the second spiral feed port 181 is set on the fuel bed 185; the air inlet 182 is set on the ash hopper 184, and the make-up air port 183 is set on the furnace 186; When the combustion fan injects air, in addition to ensuring the complete combustion of combustibles, it is also necessary to control the oxygen content in the flue gas to avoid partial oxidation of biomass when the low-temperature flue gas heats the biomass, thereby losing some organic components. As an example, the afterburning circuit also includes: exhaust gas treatment equipment 21; The exhaust gas treatment device 21 is used to control sulfur and nitrogen pollutants in the flue gas. It is connected to the new material layer 206 of the pretreatment device 20. The upgraded exhaust gas flows out from the outlet of the new material layer 206 and flows into the exhaust gas treatment device 21 (the temperature of the flue gas flowing out of the pretreatment device 20 is greater than 100°C, so as to avoid water vapor in the flue gas from condensing in the new material layer 206 and affecting the quality). The flue gas flowing out of the combustion furnace 18 is divided into four temperature gradient gases according to different stages, namely: High-temperature gas: Flue gas with T≥565℃ is used to heat hot steam and molten salt; that is, the flue gas flowing out of the combustion furnace 18 flows into the flue gas side of the superheated steam heater 17, the flue gas side of the reheated steam heater 16 and the flue gas side of the molten salt heater 22 respectively. Figure 3 middle, q 1 represents the amount of heat required to heat the steam. q 2 represents the amount of heat required to heat the molten salt; Medium-temperature gas: Flue gas with a temperature of 565℃ > T ≥ 300℃ is used for feedwater in the heating water circuit; that is, the flue gas flowing out from the flue gas side of the superheated steam heater 17, the flue gas side of the reheated steam heater 16, and the flue gas side of the molten salt heater 22. Figure 3 middle, q 3 represents the heat required to heat the water supply; Low-temperature flue gas: Flue gas with a temperature of 300℃ > T ≥ 150℃ is used for biomass upgrading as fuel; that is, the flue gas flowing out from the feedwater heater 8 is used for biomass upgrading. Figure 3 middle, q 4 represents the calories required for biomass upgrading (including drying and baking); Low-temperature waste heat flue gas: Flue gas with a temperature of 150℃ > T > 100℃ is introduced into the tail gas treatment device 21; that is, the tail gas flowing out of the pretreatment device 20; Figure 3 middle, q 5 represents the heat carried by the exhaust gas; By utilizing flue gas in stages, the thermal energy at different temperature levels can be effectively utilized, thereby improving thermal energy utilization efficiency.

[0028] Example 3: This embodiment discloses an operation method for a biomass-assisted combustion tower-type solar thermal power generation system, such as... Figure 4 As shown, this method is based on the tower solar thermal power generation system in Example 2, and adjusts the air volume and biomass feed volume in the combustion furnace 18 by changing the power generation demand of the tower solar thermal power generation system and the changes in illumination conditions, so that the temperatures of the superheated steam entering the high-pressure cylinder inlet of the steam turbine 15, the reheated steam entering the intermediate-pressure cylinder inlet of the steam turbine 15, and the molten salt entering the high-temperature molten salt tank 2 are constant; the method includes the following steps: S1: When external conditions change, adjust the flow rate of the feed water into the water circuit, the flow rate of the high-temperature molten salt in the molten salt circuit, and the flow rate of the molten salt entering the absorber in heat tower 1, specifically as follows: When the power generation demand of a tower concentrated solar power (CSP) system changes: The power of the feedwater pump 10 and the high-temperature molten salt pump in the high-temperature molten salt tank 2 are adjusted according to the power generation demand, thereby adjusting the feedwater flow rate and the high-temperature molten salt flow rate, and thus changing the flow rate of superheated steam (hereinafter referred to as the first superheated steam) at the water side outlet of the superheater 6 and the flow rate of reheated steam (hereinafter referred to as the first reheated steam) at the water side outlet of the reheater 7. Let the flow rate parameter of the first superheated steam be: Temperature parameters are Let the flow rate parameter of the first reheat steam be... Temperature parameters are ; Measurement , , and ; When lighting conditions change: The power of the low-temperature molten salt pump in the low-temperature molten salt tank 3 and the opening of the valve in the absorber buffer tank in the heat absorption tower 1 are adjusted according to the changes in light conditions, thereby adjusting the flow rate of molten salt entering the absorber and the temperature of molten salt at the outlet of the absorber changes synchronously. At this time, the molten salt temperature at the absorber outlet is greater than the starting temperature at which the molten salt condenses and freezes inside the absorber, but less than the storage temperature of the high-temperature molten salt in the high-temperature molten salt tank 2. Let the flow rate parameter of the high-temperature molten salt at the outlet of the absorber in absorber tower 1 be: Temperature parameters are The initial temperature parameter that causes molten salt condensation and freezing blockage in the absorber is: The storage temperature parameters for high-temperature molten salt are: (Typically 565°C); Measurement , , and ; in, < < ; S2: Calculate the heat required to heat the steam and the heat required to heat the high-temperature molten salt. When the power output of a tower-type concentrated solar power (CSP) system changes: The steam temperature at the inlet of the high-pressure cylinder and the steam temperature at the inlet of the intermediate-pressure cylinder of the steam turbine 15 are set (in this embodiment, the two temperatures are the same, both being...). ),pass , , , as well as Calculate the amount of heat required by superheated steam heater 17 to heat the first superheated steam. The heat required by the reheat steam heater 16 to heat the first reheat steam and the total heat required to heat the steam : ; ; ; in, The specific heat capacity of the first superheated steam. The specific heat capacity of the first reheat steam. The density of the first superheated steam. The density of the first reheat steam; When lighting conditions change: pass and Calculate the heat required to heat the high-temperature molten salt (i.e., inside the molten salt heater 22). : ; in, The specific heat capacity of high-temperature molten salt. The density of high-temperature molten salt; When both power generation and sunlight conditions change: Total calories required for: ; S3: Calculate the mass of roasted biomass Based on the heat exchange capacity of the superheated steam heater 17, the heat exchange capacity of the reheated steam heater 16, and the heat exchange capacity and performance curves of the molten salt heater 22, combined with the physical property parameters of the high-temperature flue gas flowing out of the combustion furnace 18, the following were obtained respectively. Required high-temperature flue gas flow rate , Required high-temperature flue gas flow rate and Required high-temperature flue gas flow rate And obtain the temperature of high-temperature flue gas. Calculate the total flow rate of the high-temperature flue gas. The total heat released by burning biomass during baking : ; in, The specific heat capacity of high-temperature flue gas. The density of the high-temperature flue gas. The ambient temperature is used; in this embodiment, the heat contained in the ash residue produced after the roasted biomass is burned is ignored. When the power output of a tower-type concentrated solar power (CSP) system changes: ; When lighting conditions change: ; When both power generation and sunlight conditions change: ; in accordance with Calculate the mass of roasted biomass fuel : ; Operating combustion furnace 18 (combustion furnace 18 uses roasted biomass from roasted biomass storage cell 19 as fuel); air flow rate within combustion furnace 18 Adjustments are made based on industrial and elemental analysis of roasted biomass, the excess air coefficient required for complete combustion, and the required high-temperature flue gas volume and temperature. S4: Open or close the valves (i.e., valve 24, valve 23, valve 25, valve 26, valve 27 and valve 28) to allow heat exchange between the biomass afterburning system and the molten salt circuit, and between the biomass afterburning system and the water circuit; When the power generation demand of a tower concentrated solar power (CSP) system changes: Open the fifth valve 27 to connect the flue gas side of the combustion furnace 18 and the superheated steam heater 17, so that the high-temperature flue gas generated by the combustion of roasted biomass in the combustion furnace 18 passes through the flue gas side of the superheated steam heater 17 and the temperature of the superheated steam reaches the set value. Open the sixth valve 28 to connect the flue gas side of the combustion furnace 18 and the reheat steam heater 16, so that the high-temperature flue gas generated by the combustion of roasted biomass in the combustion furnace 18 passes through the flue gas side of the reheat steam heater 17 and the temperature of the reheat steam reaches the set value. Through the above adjustments, the power generation capacity can reach the set value; When lighting conditions change: Close the first valve 24 and open the second valve 23 and the third valve 25 to connect the molten salt side of the molten salt heater 22 and the molten salt circuit, so that the high-temperature molten salt flowing out of the heat absorption tower 1 passes through the molten salt side of the molten salt heater 22. Open the fourth valve 26 to connect the flue gas side of the combustion furnace 18 and the molten salt heater 22, so that the high-temperature flue gas generated by the combustion of roasted biomass in the combustion furnace 18 passes through the flue gas side of the molten salt heater 22, so that the molten salt temperature at the inlet of the high-temperature molten salt tank 2 reaches the set value.

[0029] S5: The medium-temperature flue gas after heat exchange is introduced into the feedwater heater 8 to heat the feedwater to the set temperature. The flue gas flowing from the flue gas side of the molten salt heater 22, the flue gas side of the superheated steam heater 17, and the flue gas side of the reheated steam heater 16 is thoroughly mixed to form a medium-temperature flue gas, the temperature of which is set to [temperature value missing]. ; Calculate the outlet temperature of high-pressure heater 9 based on the water supply in the water circuit. Heat to the temperature of the water supply (That is, the temperature at the water inlet of preheater 4) required heat : ; in, For the specific heat capacity of the water, The density of the water supplied; Based on the performance curve of feedwater heater 8, at the inlet 29 on the flue gas side of the feedwater heater... and the temperature of the flue gas at the outlet 30°C on the flue gas side of the feedwater heater. Combined with the physical properties of medium-temperature flue gas , to be heated to Required flow rate of intermediate temperature flue gas : ; in, To determine the heat exchange efficiency between the flue gas side and the water side in the feedwater heater 8, The specific heat capacity of the intermediate-temperature flue gas. The density of the medium-temperature flue gas. The temperature of the low-temperature flue gas used for baking and quality improvement is the temperature of the flue gas at the outlet 30°C on the flue gas side of the feedwater heater. when hour, The medium-temperature flue gas is introduced into the flue gas side of the feedwater heater 8 to heat the feedwater (the water in the water side of the feedwater heater 8), forming low-temperature flue gas, which is then introduced into the pretreatment equipment 20; the excess flue gas after heating the feedwater (i.e., After being diluted and cooled with nitrogen, it is directly fed into the pretreatment equipment 20 for biomass upgrading, thereby avoiding the pyrolysis of biomass due to excessively high flue gas temperature (greater than or equal to 300℃); when At the same time, all the medium-temperature flue gas is fed into the flue gas side of the feedwater heater 8 to heat the feedwater and form low-temperature flue gas; the low-temperature flue gas is directly fed into the pretreatment equipment 20 for biomass upgrading; at the same time, the pump power of the high-temperature molten salt in the high-temperature molten salt tank 2 is increased, thereby increasing the flow rate of molten salt entering the superheater 6 and reheater 7, ensuring the temperature of the superheated steam entering the high-pressure cylinder of the turbine 15 and the temperature of the reheated steam entering the intermediate-pressure cylinder of the turbine 15 are stable, in order to meet the power generation requirements; As an example, in step S5, the amount of biomass to be upgraded in the pretreatment device 20 is adjusted according to the temperature and flow rate of the low-temperature flue gas.

[0030] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A tower-type solar thermal power generation system with biomass afterburning, characterized in that, include: Molten salt circuit, water circuit, and biomass-fueled afterburner circuit; The combustion circuit includes: a biomass combustion system, a molten salt heater (22), a superheated steam heater (17), a reheated steam heater (16), and a feedwater heater (8); The biomass afterburning system uses biomass as fuel and generates high-temperature flue gas in the afterburning circuit. The high-temperature flue gas is divided into three streams. The first stream of high-temperature flue gas exchanges heat with the molten salt in the pipeline between the heat absorption tower (1) and the high-temperature molten salt tank (2) in the molten salt circuit through the molten salt heater (22). The second stream of high-temperature flue gas exchanges heat with the superheated steam in the pipeline between the water side of the superheater (6) and the high-pressure cylinder of the turbine (15) in the water circuit through the superheated steam heater (17). The third stream of high-temperature flue gas exchanges heat with the reheated steam in the pipeline between the water side of the reheater (7) and the intermediate-pressure cylinder of the turbine (15) in the water circuit through the reheated steam heater (16). Finally, they are combined into one stream and form medium-temperature flue gas. The medium-temperature flue gas undergoes heat exchange with the feed water in the water circuit through the feed water heater (8) and forms low-temperature flue gas; The low-temperature flue gas is returned to the biomass combustion system for biomass upgrading.

2. The biomass-assisted combustion tower solar thermal power generation system as described in claim 1, characterized in that, The molten salt heater (22) includes a flue gas side and a molten salt side. The inlet of the flue gas side is connected to the biomass supplementary combustion system, and the molten salt side is located on the pipeline between the heat absorption tower (1) and the high-temperature molten salt tank (2) in the molten salt circuit. The superheated steam heater (17) includes a flue gas side and a water side. The inlet of the flue gas side is connected to the biomass combustion system, and the water side is located on the pipeline between the water side of the superheater (6) and the high-pressure cylinder of the steam turbine (15) in the water circuit. The reheat steam heater (16) includes a flue gas side and a water side. The inlet of the flue gas side is connected to the biomass combustion system, and the water side is located on the pipeline between the reheater (7) and the intermediate pressure cylinder of the steam turbine (15) in the water circuit. The water heater (8) includes: a flue gas side and a water side; The flue gas outlets of the molten salt heater (22), the superheated steam heater (17), and the reheated steam heater (16) are combined into one and connected to the flue gas inlet (29) of the feedwater heater. The flue gas outlet (30) of the feedwater heater is connected to the biomass supplementary combustion system. The water side of the feedwater heater (8) is located on the pipeline between the water side of the preheater (4) and the high-pressure heater (9) in the water circuit. When the three streams of high-temperature flue gas pass through the flue gas side of the molten salt heater (22), the superheated steam heater (17), and the reheated steam heater (16), they exchange heat with the molten salt side of the molten salt heater (22), the water side of the superheated steam heater (17), and the water side of the reheated steam heater (16), respectively. The medium-temperature flue gas passes through the flue gas side of the feedwater heater (8) and exchanges heat with the water side of the feedwater heater (8).

3. The tower-type solar thermal power generation system with biomass afterburning as described in claim 2, characterized in that, The combustion circuit also includes: a second valve (23), a third valve (25), a fourth valve (26), a fifth valve (27), and a sixth valve (28); The second valve (23) is installed on the pipeline between the heat absorption tower (1) and the inlet on the molten salt side of the molten salt heater (22); The third valve (25) is installed on the pipeline between the outlet of the molten salt side of the molten salt heater (22) and the high-temperature molten salt tank (2); The fourth valve (26) is installed on the pipeline between the biomass afterburning system and the flue gas inlet of the molten salt heater (22); The fifth valve (27) is installed on the pipeline between the biomass afterburning system and the flue gas inlet of the superheated steam heater (17); The sixth valve (28) is installed on the pipeline between the biomass afterburning system and the flue gas inlet of the reheat steam heater (16); The molten salt circuit also includes: a first valve (24), which is installed on the pipeline between the heat absorption tower (1) and the high-temperature molten salt tank (2) and is connected in parallel with the second valve (23), the molten salt heater (22) and the third valve (25).

4. A tower-type solar thermal power generation system with biomass afterburning as described in claim 3, characterized in that, The biomass supplementary combustion system includes: a pretreatment device (20), a roasted biomass storage room (19), a combustion furnace (18), and a tail gas treatment device (21). The pretreatment equipment (20) is used to bake and improve the quality of biomass, and its outlet is connected to the inlet of the baked biomass storage cell (19). The exhaust gas treatment device (21) is connected to the exhaust port of the pretreatment device (20); The outlet of the baking biomass storage cell (19) is connected to the inlet of the combustion furnace (18); The combustion furnace (18) is used to burn biomass; the outlet of the high-temperature flue gas of the combustion furnace (18) is divided into three streams, which are respectively connected to the fourth valve (26), the fifth valve (27) and the sixth valve (28); The outlet (30) on the flue gas side of the water heater is connected to the pretreatment equipment (20), so that the low-temperature flue gas can be used for biomass upgrading.

5. A tower-type solar thermal power generation system for biomass afterburning as described in any one of claims 2-4, characterized in that, The pretreatment equipment (20) includes: a first spiral feed inlet (201), a first spiral discharge outlet (202), a bellows (203), a baking layer (204), a drying layer (205), and a new material layer (206); The wind box (203), baking layer (204), drying layer (205) and fresh material layer (206) are arranged and connected from bottom to top; the first spiral feed inlet (201) is located on the fresh material layer (206); the first spiral discharge outlet (202) is located at the bottom of the baking layer (204) and is used to connect to the inlet of the baking biomass storage cell (19); the inlet of the wind box (203) is connected to the flue gas pipe at the outlet of the water heater (8).

6. A tower-type solar thermal power generation system with biomass afterburning as described in claim 5, characterized in that, The combustion furnace (18) includes: a second spiral feed inlet (181), an air inlet (182), a make-up air inlet (183), an ash hopper (184), a fuel bed (185), and a furnace chamber (186). The ash hopper (184), fuel bed (185), and furnace (186) are arranged sequentially from bottom to top and interconnected with each other; the exhaust port of the furnace (186) is divided into three streams, which are respectively connected to the flue gas side of the molten salt heater (22), the superheated steam heater (17), and the reheated steam heater (16); the second spiral feed port (181) is set on the fuel bed (185); the air inlet (182) is set on the ash hopper (184), and the make-up air port (183) is set on the furnace (186).

7. A method for operating a tower-type concentrated solar power (CSP) system with biomass afterburning, based on the tower-type CSP system of any one of claims 1-6, characterized in that, The method includes the following steps: S1: When the power generation demand of the tower solar thermal power generation system changes, adjust the feedwater flow rate into the water circuit and the high-temperature molten salt flow rate in the molten salt circuit; measure the flow rate of superheated steam at the water side outlet of the superheater (6) in the water circuit at this time. and temperature The flow rate of reheat steam at the water-side outlet of the reheater (7) and temperature ; When the illumination conditions change, the flow rate of molten salt entering the absorber of the heat exchanger (1) is adjusted synchronously; the flow rate of high-temperature molten salt at the outlet of the absorber of the heat exchanger (1) in the molten salt circuit is measured at this time. and temperature And at this time The temperature above the starting temperature at which molten salt condensation and freezing blockage occur inside the receiver. And less than the storage temperature of the high-temperature molten salt in the high-temperature molten salt tank (2). ; S2: When the power generation demand of the tower solar thermal power generation system changes, set the steam temperature at the high-pressure cylinder inlet and the steam temperature at the intermediate-pressure cylinder inlet of the turbine (15). and through , , , , and the specific heat capacity of superheated steam and density Specific heat capacity of reheated steam and density Calculate the amount of heat required by the superheated steam heater (17) to heat the superheated steam. The heat required to heat the reheat steam in the reheat steam heater (16) and the total heat required to heat the steam ; When lighting conditions change, through , , and the specific heat capacity of high-temperature molten salt and density Calculate the heat required to heat high-temperature molten salt ; Calculate the total heat required when both power generation and sunlight conditions change. ; S3: When the power generation demand of the tower solar thermal power generation system changes, the heat exchange and performance curves of the superheated steam heater (17) and the reheated steam heater (16), combined with the physical property parameters of the high-temperature flue gas flowing out of the combustion furnace (18), are used to obtain the following: Required high-temperature flue gas flow rate and Required high-temperature flue gas flow rate ;Measure the temperature of high-temperature flue gas and ambient temperature ;pass and Calculate the total flow rate of the required high-temperature flue gas. ; When the illumination conditions change, the heat exchange and performance curves of the molten salt heater (22) are used to obtain the physical property parameters of the high-temperature flue gas flowing out of the combustion furnace (18). Required high-temperature flue gas flow rate Measure the temperature of high-temperature flue gas and ambient temperature ;at this time, That is, the total flow rate of the required high-temperature flue gas. ; When both power generation and sunlight conditions change, through , and Calculate total flow ; and through Specific heat capacity of high-temperature flue gas Density of high-temperature flue gas as well as Calculate the total heat released by burning biomass for baking. Then, by examining the calorific value of the roasted biomass... Calculate the required mass of biomass fuel for baking. ; S4: Open or close the valve to allow heat exchange between the afterburning circuit and the molten salt circuit, and between the afterburning circuit and the water circuit; S5: The temperature of the intermediate-temperature flue gas after mixing the flue gas from the flue gas side of the molten salt heater (22), the flue gas side of the superheated steam heater (17), and the flue gas side of the reheated steam heater (16) is: ; Based on the water supply in the water circuit Specific heat capacity of water supply in water circuit and density Calculate the amount of heat required to heat the outlet temperature of the high-pressure heater (9) to the set feedwater temperature. ; Based on the performance curve of the feedwater heater (8), at the flue gas inlet (29) of the feedwater heater , combined The heat transfer efficiency between the flue gas side and the water side in the feedwater heater (8) Specific heat capacity of intermediate temperature flue gas Density of intermediate-temperature flue gas And the temperature of the flue gas used for baking and quality improvement, the temperature of the medium-temperature flue gas. Calculate the required flow rate of the intermediate-temperature flue gas. ; when hour, The medium-temperature flue gas is fed into the flue gas side of the feedwater heater (8), and after heating the feedwater, it is fed into the biomass combustion system; the excess flue gas after heating the feedwater is diluted and cooled by nitrogen and then fed into the biomass combustion system. when At the same time, all medium-temperature flue gas is fed into the flue gas side of the feedwater heater (8) to heat the feedwater and then into the biomass refueling system; at the same time, the pump power of the high-temperature molten salt in the high-temperature molten salt tank (2) is increased, thereby increasing the flow rate of molten salt entering the superheater (6) and reheater (7).

8. The operation method of a biomass-assisted combustion tower solar thermal power generation system as described in claim 7, characterized in that, In step S2: ； ； ； ； 。 9. The operation method of a biomass-assisted combustion tower solar thermal power generation system as described in claim 7 or 8, characterized in that, In step S3: ； When the power output of a tower-type concentrated solar power (CSP) system changes: ； When lighting conditions change: ； When both power generation and sunlight conditions change: ； 。 10. The operation method of a biomass-assisted combustion tower solar thermal power generation system as described in claim 7 or 8, characterized in that, In step S5: ； Excess smoke volume is .

Images