System and method for recovering sea salt from high-temperature tail gas of a thermal power plant

Abstract

The application provides a system and method for recovering sea salt from high-temperature tail gas of a thermal power plant, comprising a crystallization evaporation tank, a flue gas inlet pipeline, a flue gas outlet main pipeline, a high-concentration seawater storage pool, a filter conveyor and a sea salt storage tank, the flue gas inlet pipeline is connected with a flue gas outer cavity of the crystallization evaporation tank, an outlet of the flue gas outer cavity is connected with the flue gas outlet main pipeline, the high-concentration seawater storage pool is connected with a seawater inner cavity of the crystallization evaporation tank through a seawater inlet pipeline, a plurality of nozzles are uniformly arranged on the seawater inner cavity, an outlet of the seawater inner cavity is connected with a seawater outlet pipeline, the seawater outlet pipeline is connected with the high-concentration seawater storage pool, the filter conveyor is arranged below the crystallization evaporation tank, the sea salt storage tank is arranged below a discharge port of the filter conveyor, and the high-concentration seawater storage pool is located below a liquid discharge end of the filter conveyor. The application realizes evaporation crystallization of seawater concentrated liquid and recovery of sea salt by efficiently utilizing heat energy of boiler tail gas of the thermal power plant.

Description

Technical Field

[0001] This invention relates to the field of high-temperature exhaust gas utilization technology in thermal power plants, and in particular to a system and method for recovering sea salt from high-temperature exhaust gas in thermal power plants. Background Technology

[0002] Coastal thermal power plants typically obtain their freshwater from seawater desalination. However, the desalination process generates highly concentrated seawater, which is often not fully utilized and is instead discharged directly. Meanwhile, the flue gas temperature from the boilers in these power plants typically exceeds 140 degrees Celsius, and the heat carried away by this flue gas is usually wasted without being effectively utilized.

[0003] To fully utilize the heat from the high-concentration seawater generated by thermal power plants and the flue gas from the boiler tail, the high-temperature flue gas discharged from the boiler tail is used to heat the high-concentration seawater, causing it to evaporate rapidly and precipitate sea salt, thereby achieving efficient energy utilization and obtaining sea salt. Therefore, it is necessary to propose a system and method for recovering sea salt by heating seawater concentrate with high-temperature flue gas from thermal power plants. Summary of the Invention

[0004] The purpose of this invention is to provide a system and method for recovering sea salt from high-temperature exhaust gas from thermal power plants. The aim is to effectively utilize the high-temperature boiler exhaust gas generated by thermal power plants as a heat source to heat and evaporate the seawater concentrate produced by the seawater desalination system, thereby achieving efficient recovery of sea salt.

[0005] According to one objective of the present invention, a system for recovering sea salt from high-temperature exhaust gas of a thermal power plant is provided, comprising a crystallization evaporator, a flue gas inlet pipeline, a flue gas outlet main pipeline, a high-concentration seawater storage tank, a filter conveyor, and a sea salt storage tank. The flue gas inlet pipeline is connected to the outer flue gas cavity of the crystallization evaporator, and the outlet of the outer flue gas cavity is connected to the flue gas outlet main pipeline. The high-concentration seawater storage tank is connected to the inner seawater cavity of the crystallization evaporator via a seawater inlet pipeline. A plurality of nozzles are uniformly arranged on the inner seawater cavity. The outlet of the inner seawater cavity is connected to a seawater outlet pipeline, and the seawater outlet pipeline is connected to the high-concentration seawater storage tank. The filter conveyor is located below the crystallization evaporator, the sea salt storage tank is located below the discharge port of the filter conveyor, and the high-concentration seawater storage tank is located below the liquid discharge end of the filter conveyor.

[0006] Furthermore, the flue gas outer cavity is connected to multiple flue gas outlet branch pipes, and all of the multiple flue gas outlet branch pipes are connected to the main flue gas outlet pipe, which is equipped with an induced draft fan.

[0007] Furthermore, the main flue gas outlet pipeline is connected to the auxiliary flue gas recirculation pipeline, and the auxiliary flue gas recirculation pipeline is connected to the external flue gas cavity.

[0008] Furthermore, the seawater inlet pipeline is equipped with an inlet valve and a water pump.

[0009] Furthermore, the crystallization evaporator is equipped with a rotating frame inside, which is fixed on an annular hollow rotating disk. The annular hollow rotating disk is connected to a rotating motor, and an inner wall brush is fixed on the rotating frame.

[0010] Furthermore, the bottom of the crystallization evaporator is provided with a hopper, and the filter conveyor is located below the hopper.

[0011] Furthermore, the filter conveyor includes a drive unit, a chain, a wear-resistant liner, a drainage trough, a guide hopper, a trough body, and a scraper. The drive unit is connected to the chain, the scraper is fixed on the chain, the wear-resistant liner is fixed on the trough body, the trough body is used for temporary storage of sea salt crystals, the drainage trough is provided at the tail of the wear-resistant liner, and the guide hopper is provided at the head of the wear-resistant liner.

[0012] Furthermore, the flue gas inlet pipe is equipped with a blower and a first flue gas baffle, and the flue gas recirculation auxiliary pipe is equipped with a second flue gas baffle.

[0013] Furthermore, the high-concentration seawater storage tank is equipped with a first temperature measuring instrument, the top of the crystallization evaporator is equipped with a second temperature measuring instrument, and the flue gas outlet main pipeline is equipped with a third temperature measuring instrument; the seawater inlet pipeline is equipped with a first flow measuring instrument, the flue gas inlet pipeline is equipped with a second flow measuring instrument, the flue gas recirculation auxiliary pipeline is equipped with a third flow measuring instrument, and the flue gas outlet main pipeline is equipped with a fourth flow measuring instrument.

[0014] According to another objective of the present invention, the present invention provides a method for using the above-mentioned system for recovering sea salt from high-temperature exhaust gas from thermal power plants, comprising the following steps:

[0015] S1, the flue gas enters the flue gas outer cavity of the crystallization evaporator through the flue gas inlet pipe, and transfers heat energy to the seawater through heat exchange. Finally, the flue gas enters the flue gas outlet main pipe and is discharged into the power plant flue gas system.

[0016] S2, high-concentration seawater enters the seawater cavity of the crystallization evaporator from the high-concentration seawater storage tank through the seawater inlet pipe. The seawater cavity stores the concentrated seawater to be heated and evaporated. Part of the seawater is sprayed onto the inner wall of the evaporation cavity of the crystallization evaporator through nozzles to exchange heat with the high-temperature flue gas; the other part of the seawater flows out of the seawater cavity and returns to the high-concentration seawater storage tank through the seawater outlet pipe for circulation.

[0017] S3, after the high-concentration seawater sprayed into the evaporation chamber exchanges heat with the high-temperature flue gas, it evaporates rapidly and precipitates sea salt crystals; the sea salt crystals and the seawater that has not yet evaporated form a solid-liquid mixture, which enters the filter conveyor. On the filter conveyor, the seawater in the solid-liquid mixture is filtered and returned to the high-concentration seawater storage tank, while the sea salt crystals are transported to the sea salt storage tank for storage.

[0018] The technical solution of this invention achieves the evaporation and crystallization of seawater concentrate and the recovery of sea salt by efficiently utilizing the thermal energy of boiler exhaust gas in thermal power plants. The seawater in the evaporation chamber is heated by the high-level exhaust gas of the boiler, causing the water to evaporate rapidly and sea salt crystals to precipitate. After the high-concentration seawater is heated and evaporated in the crystallization evaporation tank, the precipitated sea salt crystals enter the sea salt storage tank at the bottom of the evaporation tank, ensuring the stable operation of the system and a high energy efficiency ratio. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention;

[0021] Figure 2 This is an embodiment of the present invention. Figure 1 A magnified view of a section at point A in the middle;

[0022] Figure 3 This is a schematic diagram of the control system according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the structure of the filter conveyor according to an embodiment of the present invention.

[0024] In the diagram, 1. Crystallization evaporator; 101. Flue gas outer cavity; 102. Rotating frame; 103. Evaporation chamber; 104. First flue gas outlet; 105. Second flue gas outlet; 106. Annular hollow rotating disk; 107. Axial flow fan; 108. Hopper; 109. Reducer; 110. Rotary motor; 111. Flue gas inlet; 112. Third flue gas outlet; 113. Seawater inner cavity; 114. Nozzle; 115. Inner wall brush; 116. Exhaust pipe; 117. Exhaust port;

[0025] 2. High-concentration seawater storage tank;

[0026] 3. Filter conveyor; 301. Drive unit; 302. Chain; 303. Wear-resistant liner; 304. Drainage trough; 305. Feed hopper; 306. Tank body; 307. Scraper; 308. Separator motor;

[0027] 4. Sea salt storage tank; 5. Blower; 6. Exhaust fan; 7. First flue gas damper; 8. Second flue gas damper; 9. Water inlet valve; 10. Water pump; 11. First temperature measuring instrument; 12. Second temperature measuring instrument; 13. Third temperature measuring instrument; 14. First flow measuring instrument; 15. Second flow measuring instrument; 16. Third flow measuring instrument; 17. Fourth flow measuring instrument; 18. Flue gas inlet pipeline; 19. First flue gas outlet branch pipeline; 20. Second flue gas outlet branch pipeline; 21. Third flue gas outlet branch pipeline; 22. Flue gas outlet main pipeline; 23. Flue gas recirculation auxiliary pipeline; 24. Seawater inlet pipeline; 25. Seawater outlet pipeline. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] Example 1

[0032] like Figure 1-4 As shown,

[0033] A system for recovering sea salt from high-temperature exhaust gas from a thermal power plant includes a flue gas system, a seawater circulation system, an evaporation and crystallization system, a sea salt conveying and separation system, and a control system, wherein:

[0034] Flue gas system: Flue gas enters the external flue gas chamber 101 of the crystallization evaporator 1 through the flue gas inlet pipe 18. The external flue gas chamber 101 guides the boiler exhaust gas into the crystallization evaporator 1 and transfers heat energy to the seawater through heat exchange. The external flue gas chamber 101 is evenly divided into three channels, allowing the flue gas to split into three streams after entering, flowing from top to bottom to the first flue gas outlet 104, the second flue gas outlet 105, and the third flue gas outlet 112 of the crystallization evaporator 1. These flue gas outlets merge through the first flue gas outlet branch pipe 19, the second flue gas outlet branch pipe 20, and the third flue gas outlet branch pipe 21, and finally enter the main flue gas outlet pipe 22. In the main flue gas outlet pipe 22, a portion of the flue gas recirculates back into the external flue gas chamber 101 through the flue gas recirculation auxiliary pipe 23, mixing with the new flue gas from the flue gas inlet pipe 18, thereby regulating the flue gas temperature in the external flue gas chamber 101. Another portion of the flue gas is discharged into the power plant's flue gas system via induced draft fan 6. The flue gas recirculation auxiliary pipeline 23 is used to recirculate a portion of the tail gas back to the evaporator to improve thermal energy utilization efficiency. A first flow meter 17 is installed on the main flue gas outlet pipeline 22.

[0035] The flue gas inlet pipe 18, the flue gas outlet branch pipe and the flue gas outlet main pipe 22 are the pipes for high-temperature flue gas to enter and leave the crystallization evaporator. The pipes used are made of corrosion-resistant and wear-resistant materials. The flue gas recirculation auxiliary pipe 23 is introduced into the tail gas recirculation system. By adjusting the tail gas flow rate and temperature, the evaporation efficiency is optimized.

[0036] Seawater circulation system: High-concentration seawater storage tank 2 is used to store high-concentration seawater to be treated. High-concentration seawater enters the seawater cavity 113 of crystallization evaporator 1 from the high-concentration seawater storage tank 2 through seawater inlet pipe 24. A water inlet valve 9 is installed on the seawater inlet pipe 24 to control the amount of high-concentration seawater entering. A water pump 10 is installed on the seawater inlet pipe 24 to transport seawater from the storage tank to the evaporator and to create positive pressure in the seawater cavity to prevent backflow.

[0037] The seawater inner cavity 113 stores the concentrated seawater to be heated and evaporated. The inner cavity 113 is designed as an annular cavity, allowing seawater to flow from bottom to top. During this flow, a portion of the seawater is sprayed onto the inner wall of the evaporation chamber 103 through nozzles 114, exchanging heat with the high-temperature flue gas. The nozzles 114 are evenly distributed across the inner cavity 113. The nozzles 114 are used to evenly spray the concentrated seawater into the evaporation chamber. The remaining seawater flows out of the inner cavity 113 and returns to the high-concentration seawater storage tank 2 through the seawater outlet pipe 25 for circulation. A first flow meter 14 is installed on the seawater inlet pipe 24.

[0038] Evaporation Crystallization System: High-concentration seawater sprayed into the evaporation chamber 103 exchanges heat with high-temperature flue gas, rapidly evaporating and precipitating sea salt crystals. Some sea salt crystals fall into the sea salt storage tank 4, while a small portion of the precipitated sea salt adheres to the wall of the evaporation chamber 103, affecting heat conduction. To remove these crystals promptly, this invention employs an inner wall brush 115 for cleaning. The inner wall brush 115 is evenly distributed on the rotating frame 102 and rotates with it, ensuring complete coverage of the inner wall of the evaporation chamber 103. The rotating frame 102 is fixed to an annular hollow rotating disk 106. The brushed-off sea salt crystals and the unevaporated seawater form a solid-liquid mixture, which enters the filter conveyor 3 through the hopper 108. On the filter conveyor 3, the seawater in the solid-liquid mixture is filtered and returned to the high-concentration seawater storage tank 2, while the sea salt crystals are transported to the sea salt storage tank 4 for storage.

[0039] Sea salt storage tank 4 collects the precipitated sea salt crystals. A round hole is opened on the side of sea salt storage tank 4 to allow seawater inlet pipe 24 to pass through and enter the seawater inner cavity 113. A mesh grille is installed at the top of sea salt storage tank 4; the mesh grille does not interfere with the collection of sea salt crystals.

[0040] Sea salt conveying and separation system: Filter conveyor 3 is used to transport sea salt crystals from the storage tank to the crystallization evaporation tank 1. The system uses scraper 307 to separate the sea salt crystals from the unevaporated seawater.

[0041] The filter conveyor 3 includes a drive unit 301, a chain 302, a wear-resistant liner 303, a drainage trough 304, a guide hopper 305, a tank body 306, scrapers 307, and a separation motor 308. The drive unit 301, driven by a motor, drives the chain and effectively transmits power to the scrapers. There are two chains 302, one on each side, connected by scrapers. The chains pull the scrapers along the track, thus conveying sea salt crystals to the sea salt storage tank. The wear-resistant liner 303 is fixed to the bottom plate of the tank body, supporting the material and the scraper chain, and is in direct contact with the sea salt crystals. The drainage trough 304 diverts seawater from the solid-liquid mixture of sea salt crystals back to a high-concentration seawater storage tank. The guide hopper 305 guides the sea salt crystals to the sea salt storage tank. The tank body 306 temporarily stores the sea salt crystals, guiding them from one end to the other to ensure orderly transport and providing necessary structural support for the equipment. Scraper 307 is used to push and move sea salt crystals, and continuous conveying of sea salt crystals can be achieved through the continuous movement of the scraper. Separator motor 308 provides power to the drive unit of the filter conveyor.

[0042] The specific operating steps are as follows: The motor 308 provides power to the drive unit 301, which is connected to the chain 302 and drives the chain 302 to rotate. The scraper 307 is connected to the two chains 302, and the chains 302 drive the scraper 307 to move, conveying the sea salt crystals to the guide hopper 305. Because there are gaps between the scraper 307 and the tank 306 and the wear-resistant liner 303, the unevaporated seawater will not enter the guide hopper 305 with the sea salt crystals, but will flow into the drainage trough 304 and finally return to the high-concentration seawater storage tank 2.

[0043] Control System: To achieve precise control of each part of the system, this invention includes a control system. This system monitors parameters such as temperature and flow rate at various points, automatically adjusting the operating status of equipment such as the blower 5, induced draft fan 6, and rotary motor 110, as well as the opening degree of the first flue gas damper 7 and the second flue gas damper 8, ensuring the system always operates at its optimal state.

[0044] The rotary motor 110 is connected to the reducer 109, which is used to adjust the rotational speed of the rotating disk and the inner wall brush. The rotary motor 110 provides power to the reducer.

[0045] The control system includes the following modules:

[0046] 1. Sensor module:

[0047] (1) Temperature measuring instruments: used to monitor the temperature at key locations, such as flue gas inlet pipe 18, flue gas outlet main pipe 22, seawater inlet pipe 24, etc.

[0048] (2) Flow measurement instrument: used to monitor the flow at key locations, especially the seawater inlet pipe 24 and the flue gas outlet main pipe 22.

[0049] 2. Controller module:

[0050] Programmable Logic Controllers (PLCs) or embedded controllers are responsible for receiving sensor data, executing control algorithms, and outputting control signals. These controllers include input ports, processing units, and output ports.

[0051] 3. Actuator Module:

[0052] (1) Rotary electric motor 110 is used to drive various mechanical parts.

[0053] (2) The forced draft fan 5 and the induced draft fan 6 are used to regulate the air volume. The forced draft fan 5 and the induced draft fan 6 are used to introduce and discharge boiler exhaust gas into the system, respectively.

[0054] (3) First flue gas baffle 7 and second flue gas baffle 8: Valves that control the direction and flow rate of flue gas. The first flue gas baffle 7 and the second flue gas baffle 8 are used to regulate the flow rate of the tail gas entering the crystallization evaporator 1.

[0055] 4. Human-Machine Interface (HMI) Module:

[0056] (1) Display screen or control panel: used by operators to monitor system status and adjust parameters.

[0057] (2) Buttons and switches: for manual operation and emergency stop.

[0058] 5. Communication module:

[0059] Data bus or network interface: Used for data transmission between sensors, controllers, and actuators. Common communication protocols include Modbus, CAN, and Ethernet.

[0060] Monitoring and Regulation: Multiple temperature and flow measuring instruments are installed at key locations such as the flue gas inlet pipe 18, the main flue gas outlet pipe 22, and the seawater inlet pipe 24 to monitor the system's operating status in real time. Simultaneously, by adjusting the parameters of equipment such as the forced draft fan 5 and the induced draft fan 6, as well as the opening degrees of the first and second flue gas dampers 7 and 8, precise control of the flue gas temperature and flow rate can be achieved.

[0061] The control and regulation system achieves precise control of flue gas temperature and flow rate through the following methods:

[0062] 1. Sensor data acquisition: Temperature and flow measurement instruments monitor data in real time and transmit it to the controller via the communication module.

[0063] 2. Control Algorithm Processing: The controller uses a preset control algorithm (such as PID control combined with fuzzy control) to process sensor data and calculate the required control signal.

[0064] 3. Control of the executing agency:

[0065] (1) Adjustment of the first flue gas baffle 7 and the second flue gas baffle 8:

[0066] First flue gas baffle 7: By comparing the data from the second flow meter 15 with the preset flue gas flow value, when the flow rate is detected to be greater than the preset value, the controller automatically adjusts the opening of the first flue gas baffle 7 to reduce the amount of flue gas entering the crystallization evaporator 1.

[0067] Second flue gas baffle 8: By comparing the data from the third flow meter 16 with the preset exhaust flue gas flow value, when the flow rate is detected to be greater than the preset value, the controller automatically adjusts the opening of the second flue gas baffle 8 to reduce the amount of flue gas discharged from the crystallization evaporator 1.

[0068] (2) Adjustment of blower 5 and induced draft fan 6:

[0069] Blower 5: The controller adjusts the speed of blower 5 based on data from the first temperature measuring instrument 11 and the second flow measuring instrument 15. When the first temperature measuring instrument 11 detects that the temperature is lower than the preset value or the second flow measuring instrument 15 detects that the flow rate is lower than the preset value, the controller increases the speed of blower 5 to increase the amount and temperature of flue gas entering the crystallization evaporator 1.

[0070] The induced draft fan 6 is regulated by a combination of data from the second temperature measuring instrument 12 and the third flow measuring instrument 16. When the second temperature measuring instrument 12 detects that the temperature is higher than the preset value or the third flow measuring instrument 16 detects that the flow rate is higher than the preset value, the controller increases the speed of the induced draft fan 6 to accelerate the discharge of flue gas from the crystallization evaporator 1.

[0071] A third temperature measuring instrument 13 is also installed in the flue gas outlet main pipeline 22 to measure the flue gas temperature in the flue gas outlet main pipeline 22 in real time.

[0072] (3) Adjustment of rotary motor 110:

[0073] The rotary motor 110 controls the rotation speed of the rotating frame 102 and the inner wall brush 115. When the first temperature measuring instrument 11 and the second temperature measuring instrument 12 detect an increase in temperature and the second flow measuring instrument 15 and the third flow measuring instrument 16 detect an increase in flow rate, it indicates that the evaporation efficiency has improved, which may lead to more sea salt crystals adhering to the wall of the evaporation chamber 103. The controller will then increase the rotation speed of the rotary motor 110 to accelerate the cleaning speed of the inner wall brush 115.

[0074] 4. The overall control process of the control system:

[0075] (1) Sensor data acquisition: Data from all temperature and flow measuring instruments are transmitted to the controller via the communication module.

[0076] (2) Control algorithm processing: The controller uses a preset control algorithm (such as PID control combined with fuzzy control) to process the sensor data and calculate the required control signal.

[0077] (3) Actuator control: The controller outputs control signals based on the processed data to adjust the working status of the blower 5, the induced draft fan 6, the rotary motor 110, the first flue gas damper 7, and the second flue gas damper 8.

[0078] (4) Feedback loop: The sensor monitors the adjusted state in real time and feeds the data back to the controller to form a closed-loop control, ensuring the stable and efficient operation of the system.

[0079] In the above embodiments, the crystallization evaporator 1 is a device for extracting sea salt crystals from high-concentration seawater. Its working principle mainly involves heating the seawater in the evaporation chamber using the high-level exhaust gas from the boiler, causing the water to evaporate rapidly and thus precipitating sea salt crystals. The evaporator is made of corrosion-resistant and high-temperature-resistant alloy materials to ensure stable operation in high-temperature and corrosive environments.

[0080] First, the evaporation chamber is equipped with a high-efficiency nozzle array to ensure uniform spraying of the seawater concentrate, improving heat exchange efficiency. High-concentration seawater is evenly sprayed into the evaporation chamber through these nozzles. Simultaneously, high-temperature exhaust gas from the boiler enters the high-temperature flue gas outer cavity through the flue gas inlet. As this exhaust gas passes through the high-temperature flue gas outer cavity, its heat is transferred to the evaporation chamber through the heat-conducting walls, raising the temperature inside the evaporation chamber and heating the mist-like seawater, causing it to evaporate rapidly. The resulting water vapor accumulates in the steam chamber and is eventually discharged from the exhaust port at the top of the steam chamber.

[0081] During evaporation, the water in the seawater gradually evaporates, while the dissolved salt gradually concentrates and precipitates as crystals. Most of the precipitated sea salt crystals fall directly into the sea salt storage tank at the bottom of the crystallization evaporator for easy collection and processing. However, some sea salt crystals may adhere to the inner wall of the evaporation chamber, affecting heat conduction efficiency. To solve this problem, the crystallization evaporator is equipped with an automatic rotating inner wall cleaning device. A mechanical brush removes the crystals from the inner wall. A motor drives a rotating disk, which in turn moves the mechanical brush, causing it to rotate on the inner wall of the evaporation chamber, thus removing the adhering crystals. These removed crystals also fall into the sea salt storage tank.

[0082] The main components of the crystallization evaporator 1 include an evaporation chamber 103, an outer flue gas chamber 101, a nozzle 114, an inner seawater chamber 113, an inner wall brush 115, a rotating frame 102, a rotating motor 110, a flue gas inlet 111, a flue gas outlet, a steam chamber, an exhaust pipe 116, an exhaust port 117, and a sea salt storage tank. These components work together to ensure that the crystallization evaporator can efficiently and stably extract sea salt crystals from seawater.

[0083] The top of the crystallization evaporator 1 is provided with a flue gas inlet 111, which allows boiler exhaust gas to enter the crystallization evaporator 1.

[0084] Exhaust pipe 116 allows water vapor to be discharged from crystallization evaporator 1. Exhaust port 117 allows water vapor to be discharged from the system. An axial flow fan 107 is installed on exhaust pipe 116 to draw out a large amount of water vapor.

[0085] The high-concentration seawater storage tank 2 is made of corrosion-resistant materials and equipped with an automatic stirring device to prevent seawater sedimentation. The high-concentration seawater storage tank has two main interfaces: an inlet and an outlet. High-concentration seawater generated during the desalination process of the thermal power plant enters the storage tank through the inlet for temporary storage and buffering. The design of the storage tank typically considers the seawater flow rate, concentration, and system processing capacity to ensure a stable and continuous supply of seawater to subsequent treatment stages. Pump 10 uses suction to extract the high-concentration seawater from the outlet of the storage tank and transports it through pipelines to the crystallization evaporator.

[0086] After being heated and evaporated in a crystallization evaporator, the high-concentration seawater precipitates into a sea salt storage tank 4 at the bottom of the evaporator. This sea salt storage tank 4 collects and stores the sea salt crystals, ensuring effective salt recovery and subsequent utilization. The sea salt storage tank 4 is designed to be sealed to prevent the sea salt from getting damp and contaminated.

[0087] The blower 5 is mainly used to send the high-temperature exhaust gas generated by the boiler into the crystallization evaporator to heat the high-concentration seawater inside. Through the action of the blower, it is ensured that the high-temperature exhaust gas effectively enters the evaporator, providing the necessary heat energy to the seawater, causing it to evaporate rapidly and precipitate pure sea salt crystals.

[0088] In the crystallization evaporator system, after the boiler exhaust gas completes heat exchange with high-concentration seawater, the exhaust gas is extracted from the evaporator by the induced draft fan 6 and transported back to the power plant's flue gas system through the pipeline system.

[0089] In summary, this invention provides a system and method for recovering sea salt from high-temperature flue gas from thermal power plants. By efficiently utilizing the thermal energy of boiler flue gas from thermal power plants, it achieves the evaporation and crystallization of seawater concentrate and the recovery of sea salt. Simultaneously, a precise control system and monitoring and adjustment mechanism ensure stable system operation and a high energy efficiency ratio.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for recovering sea salt from high-temperature exhaust gas from a thermal power plant, characterized in that, The system includes a crystallization evaporator, a flue gas inlet pipe, a flue gas outlet main pipe, a high-concentration seawater storage tank, a filter conveyor, and a sea salt storage tank. The flue gas inlet pipe is connected to the outer flue gas cavity of the crystallization evaporator, and the outlet of the outer flue gas cavity is connected to the flue gas outlet main pipe. The high-concentration seawater storage tank is connected to the inner seawater cavity of the crystallization evaporator via a seawater inlet pipe. Several nozzles are evenly arranged on the inner seawater cavity, and the outlet of the inner seawater cavity is connected to a seawater outlet pipe, which is connected to the high-concentration seawater storage tank. The filter conveyor is located below the crystallization evaporator, the sea salt storage tank is located below the discharge port of the filter conveyor, and the high-concentration seawater storage tank is located below the liquid discharge end of the filter conveyor. The outer flue gas cavity is connected to multiple flue gas outlet branch pipes. Multiple flue gas outlet branch pipes are connected to the main flue gas outlet pipe, and an induced draft fan is installed on the main flue gas outlet pipe; the main flue gas outlet pipe is connected to the flue gas recirculation auxiliary pipe, and the flue gas recirculation auxiliary pipe is connected to the flue gas outer cavity; the crystallization evaporator is equipped with a rotating frame inside, the rotating frame is fixed on an annular hollow rotating disk, the annular hollow rotating disk is connected to a rotary motor, and an inner wall brush is fixed on the rotating frame; the filter conveyor includes a drive device, a chain, a wear-resistant liner, a drainage trough, a guide hopper, a trough body, and a scraper, the drive device is connected to the chain, the scraper is fixed on the chain, the wear-resistant liner is fixed on the trough body, the trough body is used for temporary storage of sea salt crystals, the tail of the wear-resistant liner is provided with the drainage trough, and the head of the wear-resistant liner is provided with the guide hopper.

2. The system for recovering sea salt from high-temperature exhaust gas from thermal power plants according to claim 1, characterized in that, The seawater inlet pipeline is equipped with an inlet valve and a water pump.

3. The system for recovering sea salt from high-temperature exhaust gas from thermal power plants according to claim 1, characterized in that, The bottom of the crystallization evaporator is equipped with a hopper, and the filter conveyor is located below the hopper.

4. The system for recovering sea salt from high-temperature exhaust gas from thermal power plants according to claim 1, characterized in that, The flue gas inlet pipe is equipped with a blower and a first flue gas baffle, and the flue gas recirculation auxiliary pipe is equipped with a second flue gas baffle.

5. The system for recovering sea salt from high-temperature exhaust gas from thermal power plants according to claim 1, characterized in that, The high-concentration seawater storage tank is equipped with a first temperature measuring instrument, the top of the crystallization evaporator is equipped with a second temperature measuring instrument, and the flue gas outlet main pipeline is equipped with a third temperature measuring instrument; the seawater inlet pipeline is equipped with a first flow measuring instrument, the flue gas inlet pipeline is equipped with a second flow measuring instrument, the flue gas recirculation auxiliary pipeline is equipped with a third flow measuring instrument, and the flue gas outlet main pipeline is equipped with a fourth flow measuring instrument.

6. The method of using the system for recovering sea salt from high-temperature exhaust gas from thermal power plants according to claim 1, characterized in that, Includes the following steps: S1, the flue gas enters the flue gas outer cavity of the crystallization evaporator through the flue gas inlet pipe, and transfers heat energy to the seawater through heat exchange. Finally, the flue gas enters the flue gas outlet main pipe and is discharged into the power plant flue gas system. S2, high-concentration seawater enters the seawater cavity of the crystallization evaporator from the high-concentration seawater storage tank through the seawater inlet pipe. The seawater cavity stores the concentrated seawater to be heated and evaporated. Part of the seawater is sprayed onto the inner wall of the evaporation cavity of the crystallization evaporator through nozzles to exchange heat with the high-temperature flue gas; the other part of the seawater flows out of the seawater cavity and returns to the high-concentration seawater storage tank through the seawater outlet pipe for circulation. S3, after the high-concentration seawater sprayed into the evaporation chamber exchanges heat with the high-temperature flue gas, it evaporates rapidly and precipitates sea salt crystals; the sea salt crystals and the seawater that has not yet evaporated form a solid-liquid mixture, which enters the filter conveyor. On the filter conveyor, the seawater in the solid-liquid mixture is filtered and returned to the high-concentration seawater storage tank, while the sea salt crystals are transported to the sea salt storage tank for storage.

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