Flue gas waste heat recovery and purification system

Abstract

The utility model provides a flue gas waste heat recovery and purification system which comprises a discharge device, a purification tower, a circulating water storage device, a heat pump unit and a pulse automatic decontamination device, a plurality of rotational flow atomizers and a plurality of stages of rotational flow demisters are combined in the purification tower, the convective heat exchange capacity of flue gas and circulating water is enhanced, and the heat exchange efficiency of the flue gas is improved. More flue gas waste heat is captured into the circulating water, more flue gas condensate can be separated and collected into the circulating water, the smoke exhaust latent heat loss is greatly reduced, and the purification operation water consumption is also reduced; through the two-stage arrangement of the circulating water storage device and the pulse automatic decontamination device, the water quality of purified circulating water is greatly improved, the waste heat recovery capacity is improved, system scaling and sewage blockage are reduced, scouring and abrasion of a heat exchanger are reduced, and the purification efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of flue gas waste heat recovery and flue gas purification technology, specifically to a high-temperature flue gas waste heat recovery and purification system that can meet the self-circulation needs of heating. Background Technology

[0002] Currently, during operation, the flue gas temperature in coal-fired power plant boilers is mostly between 110-150℃, and heat loss can reach 4%-8% of the total input fuel heat of the power plant. A large amount of waste heat from the flue gas is not effectively utilized and is directly discharged into the atmosphere, resulting in energy waste. At present, the common method for utilizing waste heat from power plant boiler flue gas is to install a flue gas heat exchanger in the tail flue of the boiler. This waste heat recovery method is currently the most widely used technology for direct utilization of waste heat from flue gas. However, its improvement in energy utilization rate is no more than 2%, and a large amount of sensible and latent heat from the flue gas still cannot be recovered, resulting in waste.

[0003] Furthermore, thermal power plants commonly employ wet purification processes. The counter-current flow and direct heat exchange between flue gas and the circulating purification slurry within the purification tower transform the flue gas from high-temperature dry flue gas into low-temperature saturated wet flue gas. Part of the sensible heat and all of the latent heat of the flue gas are simultaneously discharged into the atmosphere. The water vapor absorbed by the flue gas from the purification slurry accounts for approximately 80% of the purification water consumption, resulting in the wet-purified flue gas being humidified to a saturated wet flue gas of around 50℃-60℃, mostly in a saturated or near-saturated state. However, the effective contact area between the purification slurry and flue gas in existing purification towers is small, resulting in insufficient capture capacity and inability to effectively carry away particulate matter, leading to insufficient purification efficiency. Additionally, the filtered saturated wet flue gas cannot be effectively condensed and removed, resulting in poor water recovery. The flue gas, containing a large amount of latent heat of vaporization and water resources, is not effectively recovered and utilized, and the heat contained in the approximately 20℃ temperature difference is discharged into the atmosphere as the latent heat of vaporization of water vapor. Utility Model Content

[0004] The purpose of this invention is to solve the aforementioned technical problems, thereby providing a flue gas waste heat recovery and purification system. This system employs a direct flue gas condensation method, comprehensively considering increasing the liquid-to-gas ratio of the purification spray, improving the mass and heat transfer efficiency within the purification tower, and rationally selecting a low-resistance, high-efficiency gas-liquid separation and demister device. Simultaneously, in conjunction with a heat pump unit process system, it achieves deep recovery and utilization of flue gas waste heat, reducing the flue gas temperature to 20-25℃, or even lower. The specific system structure is as follows:

[0005] A flue gas waste heat recovery and purification system includes an emission device, a purification tower, a circulating water storage device, a heat pump unit, and a pulse automatic decontamination device. The flue gas inlet at the bottom of the purification tower is connected to the flue gas outlet of a boiler via a pipe, and the flue gas outlet at the top of the purification tower is connected to the emission device via a pipe. The circulating water storage device includes a cold water pool and a hot water pool, which are isolated from each other. The circulating water storage device is equipped with a cold water pool outlet, a cold water pool inlet, a hot water pool outlet, and a hot water pool inlet. A spray device and a multi-stage cyclone demister located above the spray device are installed inside the purification tower. The inlet of the spray device is connected to... The cold water tank outlet is connected and includes multiple cyclone atomizers; each cyclone atomizer includes a cyclone atomizer shell, a cyclone flow path, an airflow inlet, a liquid inlet pipe, an atomized liquid outlet, and an airflow outlet; the outlet at the bottom of the purification tower is connected to the hot water tank inlet via a pipe, and the cold water tank inlet is connected to the heat pump unit outlet via a pipe; the hot water tank outlet is connected to a pulse automatic cleaning device via a pipe, the pulse automatic cleaning device including a cyclone drainer and a degassing drainer connected in series; the cyclone demister includes a streamlined guide tube, three-stage centrifugal separation guide vanes, and a droplet collection separator.

[0006] Furthermore, the swirl atomizer shell is annular, with a liquid phase inlet pipe tangentially positioned to receive water flow from the cold water tank outlet. An "L"-shaped air-assisted intake pipe is connected to the tangential inlet section of the swirl atomizer shell. The airflow inlet of the air-assisted intake pipe is perpendicular to the liquid phase inlet pipe, and the airflow outlet of the air-assisted intake pipe is parallel to the axis of the liquid phase inlet pipe. An atomized liquid outlet is located on the lower surface of the swirl atomizer shell. The swirl path is formed by the inner wall of the swirl atomizer shell. The airflow and the water flow from the cold water tank outlet simultaneously enter the swirl path tangentially, mix and accelerate, and are ejected from the atomized liquid outlet, forming an umbrella-shaped water mist composed of fine droplets.

[0007] Furthermore, the diameter of the swirling atomizer shell is 26-35mm, and the diameter of the swirling flow path is 8-12mm.

[0008] Furthermore, the eccentric angle of the eccentric filter cylinder is 56-61°, preferably 58°, and it adopts an assembled structure, is made of stainless steel, and the eccentric filter is umbrella-shaped.

[0009] Furthermore, the cyclone drainer includes a main cyclone cylinder and an eccentric filter cylinder. The main cyclone cylinder includes an inlet, an upper outlet, a discharge port, and an inspection port. The inlet is connected to the hot water tank outlet via a pipe, and the upper outlet is connected to the inlet of the deaeration drainer. The deaeration drainer includes an outlet and a pressure automatic exhaust valve, which is connected to the heat pump unit inlet via a pipe. The discharge port of the cyclone drainer and the deaeration discharge port of the deaeration drainer are respectively connected to the cold water tank inlet via pipes.

[0010] Furthermore, circulating water pumps are installed on each pipeline.

[0011] Furthermore, the circulating water storage device adopts a hot and cold partition, including a pool wall, a surface corrosion-resistant layer, a heat insulation layer, and mutually isolated cold water pools and hot water pools. An internal partition is set between the cold water pools and hot water pools, and a balance overflow pipe is left at the top of the internal partition.

[0012] Furthermore, the heat pump unit is a corrosion-resistant heat pump unit, which is connected to the heating network. The water in the heating network returns to the heating network after exchanging heat with the heat pump unit. Furthermore, the heat pump unit is an electric compression heat pump.

[0013] The present invention achieves the following technical effects through the innovative design of the above-described specific structure:

[0014] 1. The purification tower of the flue gas waste heat recovery and purification system integrates purification and heat exchange. Through independent research and development and modification of the internal spray device and demister device, the convective heat exchange capacity between flue gas and circulating water is enhanced, allowing more flue gas waste heat to be captured into the circulating water. Then, through coupled heat pump technology, more flue gas waste heat is transferred to the heat exchange medium. At the same time, the fine circulating water atomized particles enhance and promote the purification chemical reaction rate, improving purification efficiency. The improvement of the demister device is conducive to the separation and collection of more flue gas condensate into the circulating water, which greatly reduces the latent heat loss of flue gas and also reduces the water consumption of purification operation.

[0015] 2. The two-stage setup of the circulating water storage device and the pulse automatic cleaning device greatly improves the water quality of the purified circulating water, which is conducive to improving the waste heat recovery capacity, reducing system scaling and clogging, reducing heat exchanger scouring and wear, and improving purification efficiency.

[0016] 3. The cyclone demister in the purification tower adopts a multi-stage design with a resistance of 60-180 Pa and an average inlet particulate matter concentration of 5.8 mg / m³. 3 The average concentration of particulate matter at the outlet was 5.5 mg / m³. 3 The outlet particulate matter concentration is lower than the inlet concentration. The flue gas resistance loss is 50-100 Pa greater than that of a flat plate demister, but the water collection effect is excellent, allowing more flue gas condensate to flow back to the purification circulating water system.

[0017] 4. The pulse automatic cleaning device is suitable for concentrations of 1.6 g / cm³. 3 The system effectively removes rust, mud, and sand impurities with a particle size of 0.05mm and 0.32mm, achieving a 98% removal efficiency. The two-stage setup of the hot and cold water tanks and the filtration system significantly improves the quality of the purified circulating water, enhances waste heat recovery, reduces scaling and clogging, minimizes heat exchanger erosion and wear, and ultimately improves purification efficiency.

[0018] 5. For cyclone separators, water enters the cylinder tangentially. Under the action of centrifugal force and gravity, silt and particulate impurities settle into the sludge accumulation zone of the cylinder. After removing large particles, the water still contains tiny particles and insoluble gases that are difficult to capture and remove. To further reduce the scouring, wear, and sludge accumulation of particulate matter on system pipes and valves, as well as the cavitation of pump impellers caused by insoluble gases, and to reduce water-air impact accidents, an automatically operating deaerator is connected in series after the cyclone separator. This deaerator uses air-water separation, spiral sedimentation, and precision filtration to allow insoluble gases to accumulate in the gas buffer zone at the top of the cylinder after entering, and then be discharged through an automatic pressure exhaust valve. This deaerator can effectively remove impurities larger than 5μm. The impurities settle in the sludge accumulation zone at the bottom of the cylinder and are automatically discharged, reducing labor intensity and saving water resources.

[0019] 6. The system utilizes an electric compression heat pump, which can solve the problem of "more electricity than heat" imbalance in thermal power plants, address the limitation of power output in small thermal power units, and improve the economy and flexibility of heating units. The system's waste heat recovery capability is specifically manifested in the surplus of the heat pump unit, i.e., the heat pump's ability to extract waste heat. The recovered heat can be used to heat the return water for winter heating. The system's heating capacity has significantly higher recovery potential and purification effect than similar flue gas purification and recovery systems. The COP performance, a key indicator for evaluating the heat pump system's recovery performance, is excellent. This flue gas waste heat recovery and purification system can be extended to waste heat recovery and purification of gas-fired combined cycle boilers and gas-fired boilers, and can also be extended to waste heat recovery and purification of marine diesel engines, achieving cascade utilization of heat. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 : Structural diagram of the flue gas waste heat recovery and purification system of this application.

[0022] Figure 2 : A schematic diagram of the structure of the multi-stage cyclone demister of this application.

[0023] Figure 3 : A schematic diagram of the overall structure of the pulse automatic decontamination device of this application.

[0024] Figure 4 : A schematic diagram of the cyclone drainer of this application.

[0025] Figure 5 : A bottom view of the vortex atomizer of this application.

[0026] Figure 6 Side view of the vortex atomizer of this application.

[0027] Figure 7 : Front view of the circulating water storage device of this application.

[0028] Figure 8 : Schematic diagram of the internal structure of the circulating water storage device of this application.

[0029] Figure label:

[0030] 1-Emission device; 2-Purification tower; 3-Multi-stage cyclone demister; 31-Streamlined guide pipe; 32-Three-stage centrifugal separation guide vane; 33-Droplet collector and separator; 4-Spraying device; 5-Circulating water storage device; 5a-Cold water tank; 5b-Hot water tank; 51-Cold water tank outlet; 52-Cold water tank inlet; 53-Hot water tank outlet; 54-Hot water tank inlet; 55-Sewage outlet; 6-Heat pump unit; 7-Pulse automatic cleaning device; 71-Cyclone drainer; 72-Deaeration drainer; 711-Main cyclone 712-Eccentric filter cylinder; 7111-Inlet; 7112-Upper outlet; 7113-Discharge port; 7114-Inspection port; 721-Automatic pressure exhaust valve; 722-Degassing discharge port; 723-Outlet; 8-Swirl atomizer; 81-Swirl atomizer housing; 82-Swirl flow path; 83-Airflow inlet; 84-Liquid phase inlet pipe; 85-Atomized liquid outlet; 86-Airflow outlet; 9-Pool wall; 91-Internal partition; 92-Balance overflow pipe; 93-Surface corrosion-resistant layer; 94-Insulation layer. Detailed Implementation

[0031] The technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. It is obvious that the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0032] like Figure 1As shown, the flue gas waste heat recovery and purification system includes an emission device 1, a purification tower 2, a circulating water storage device 5, a heat pump unit 6, and a pulse automatic decontamination device 7. The flue gas inlet at the bottom of the purification tower 2 is connected to the flue gas outlet of the boiler through a pipe, and the flue gas outlet at the top of the purification tower 2 is connected to the emission device 1 through a pipe. The circulating water storage device 5 includes a cold water pool 5a and a hot water pool 5b that are isolated from each other. A spray device 4 and a multi-stage cyclone demister 3 located above the spray device 4 are provided inside the purification tower 2. The inlet of the spray device 4 is connected to the outlet 51 of the cold water pool through a pipe and includes multiple cyclone atomizers 8. The outlet at the bottom of the purification tower 2 is connected to the inlet 54 of the hot water pool through a pipe. The inlet 52 of the cold water pool is connected to the outlet of the heat pump unit 6 through a pipe. The outlet 53 of the hot water pool is connected to the inlet of the pulse automatic decontamination device 7 through a pipe. The outlet of the pulse automatic decontamination device 7 is connected to the inlet of the heat pump unit 6 through a pipe.

[0033] The cyclone demister includes a streamlined guide tube 31, three-stage centrifugal separation guide vanes 32, and a droplet collection separator 33. Flue gas enters the cyclone demister 31 through the streamlined guide tube 31, colliding with the streamlined guide tube 31 and the three-stage centrifugal guide vanes 32 during its flow, removing large droplets and dust particles. The flue gas then enters the droplet separator 33 to remove smaller droplets and dust particles, improving removal efficiency. The cyclone demister has a resistance of 60-180 Pa and an average inlet particulate matter concentration of 5.8 mg / m³. 3 The average concentration of particulate matter at the outlet was 5.5 mg / m³. 3 The outlet particulate matter concentration is lower than the inlet concentration. The flue gas resistance loss is 50-100 Pa greater than that of a flat plate demister, but the water collection effect is excellent, allowing more flue gas condensate to flow back to the purification circulating water system.

[0034] The spray device 4 includes multiple swirling atomizers 8. Each swirling atomizer 8 includes a swirling atomizer housing 81, a swirling flow path 82, an airflow inlet 83, a liquid inlet pipe 84, an atomized liquid outlet 85, and an airflow outlet 86. The swirling atomizer housing 81 is annular. A liquid inlet pipe 84 is provided tangentially to the swirling atomizer housing 81 to receive water flow from the cold water pool outlet 51. An "L"-shaped air-assisted intake pipe is connected to the tangential inlet section of the swirling atomizer housing 81. The air inlet 83 of the air intake pipe is perpendicular to the liquid phase inlet pipe 84, and the air outlet 86 of the air-assisted intake pipe is parallel to the axis of the liquid phase inlet pipe 84. An atomized liquid outlet 85 is provided on the lower surface of the vortex atomizer housing 81. The vortex flow path 82 is surrounded by the inner wall of the vortex atomizer housing 81. Airflow and water flow from the cold water pool outlet 51 simultaneously enter the vortex flow path 82 tangentially, mix and accelerate, and are ejected from the atomized liquid outlet 85, forming an umbrella-shaped water mist composed of fine droplets. The diameter of the vortex atomizer housing 81 is 26-35 mm, and the diameter of the vortex flow path 82 is 8-12 mm. The pressure loss of the airflow from entry to exit is between 0.04-0.11 MPa, resulting in low jet resistance. The atomized particles are finer than those from conventional nozzles, and the atomization cone angle is large, providing a wider effective contact area with the flue gas, greatly enhancing the circulating water's ability to capture waste heat from the flue gas and its purification performance.

[0035] The pulse automatic decontamination device 7 includes a cyclone drainer 71 and a deaeration drainer 72 connected in series. The discharge port of the cyclone drainer 71 and the deaeration discharge port 722 of the deaeration drainer 72 are connected to the inlet 52 of the cold water tank via pipes. The cyclone drainer 71 includes a main cyclone cylinder 711 and an eccentric filter cylinder 712. The main cyclone cylinder 711 includes an inlet 7111, an upper outlet 7112, a discharge port 7113, and an inspection port 7114. In the main cyclone cylinder 711, dirt swirls along the cylinder wall under the action of water flow and its own gravity and is discharged to the bottom outlet. The eccentric angle of the eccentric filter cylinder 712 is 58°, and it adopts an assembled structure, is made of stainless steel, and has an umbrella-shaped filter screen. The deaeration drainer 72 is controlled by a PLC chip, which controls the opening and closing of the solenoid valve or electric valve according to the pressure difference, effluent turbidity, or running time, and automatically discharges dirt during operation. The pulse automatic decontamination device 7 is suitable for concentrations of 1.6 g / cm³. 3 The system effectively removes rust, mud, and sand impurities with a particle size of 0.05 mm and 0.32 mm, achieving a decontamination efficiency of 98%. The two-stage setup of the circulating water storage device 5 and the pulse automatic decontamination device 7 significantly improves the water quality of the purified circulating water, enhances waste heat recovery capabilities, reduces system scaling and clogging, minimizes heat exchanger scouring and wear, and ultimately improves purification efficiency.

[0036] Heat pump unit 6 is connected to the heating network. Water returns to the heating network after heat exchange in heat pump unit 6. Heat pump unit 6 is a corrosion-resistant heat pump unit, such as an electric compression heat pump. The entire flue gas waste heat recovery and purification system forms a closed loop. Electric compression heat pumps can solve the problem of power plant electricity shortage and power imbalance, and solve the dilemma of limited power output of small thermal power units, thus improving the economy and flexibility of heating units.

[0037] The flue gas waste heat recovery and purification system of this application operates as follows: During operation, boiler flue gas (90-130℃) enters the purification tower 2 via an induced draft fan. Simultaneously, water enters the purification tower 2 from a cold water pool 5a and is sprayed downwards through a cyclone atomizer 8. The falling water exchanges heat with the rising flue gas, dissolving and settling inorganic substances in the flue gas. After purification, the flue gas passes through a multi-stage cyclone demister 3 for demisting and further cooling before being discharged from the purification tower 2 and finally through an emission device 1. Depending on the ambient temperature during winter, the flue gas temperature changes to 18-25℃. Water injected into purification tower 2 accumulates at the bottom of tower 2, where its temperature rises by 10-15°C. It is then discharged into the hot water tank 5b of the circulating water storage device 5. Water from hot water tank 5b is pumped by a circulating water pump into a series-connected cyclone separator 71 and degassing separator 72. First, the water and insoluble matter are separated by cyclone separation in cyclone separator 71. The separated water then enters degassing separator 72, where it reacts, releasing gas and forming precipitate. The reacted water is then filtered and enters heat pump unit 6. The separated insoluble matter and filtered solids undergo further dehydration and are sent to the waste residue storage. The dehydrated water is returned to the cold water tank 5a of the circulating water storage device 5 via pipeline. Water entering heat pump unit 6, after heat exchange, is sent to the cold water tank 5a of the circulating water storage device 5. The refrigerant in heat pump unit 6 exchanges heat with the water entering unit 6 before entering the heating network to provide heating for the heating area. The refrigerant is heated in the evaporator and becomes a high-temperature, low-pressure gas. After passing through the compressor, it becomes a high-temperature, high-pressure gas. It then enters the condenser to exchange heat with the circulating water and becomes a high-pressure, low-temperature liquid. After passing through the expansion valve, it is depressurized and becomes a low-temperature, low-pressure liquid that enters the evaporator for circulation.

[0038] The circulating water storage device 5 adopts a hot and cold partition design, including a water tank wall 9 and mutually isolated cold water tank 5a and hot water tank 5b, with an internal partition 91 between them and a balance overflow pipe 92 at the top of the internal partition 91. The circulating water storage device 5 can separate the desulfurization slurry into hot and cold sections during the operation of the flue gas waste heat recovery and purification system, and can also balance the overflow when the circulation between the cold water tank 5a and the hot water tank 5b is uneven, facilitating actual system operation. The balance overflow pipe 92 can also allow the desulfurization circulation system to maintain independent circulation when the flue gas waste heat recovery and purification system stops operating. The cold water tank 5a and hot water tank 5b can be constructed using concrete, brick-concrete structures, or steel structures to ensure structural strength. A heat insulation layer 94 is then formed on the surface using heat insulation materials such as rock wool to reduce heat loss and conduction of the desulfurization slurry. Finally, a corrosion-resistant surface layer 93 is formed by treating the surface with corrosion-resistant materials such as glass flakes or PP. The high-temperature circulating water flowing out of the self-purification tower 2 flows to the hot water tank 5b. After sampling and testing, a slow-release scale inhibitor is added to reduce the hardness of the circulating water. Then, the circulating water is pressurized by the circulating pump and flows through the pulse automatic cleaning device 7 to remove the silt particles and the silicon-calcium compounds generated by the reaction, thereby improving the water quality. The purified high-temperature circulating water directly enters the heat pump unit 6, releasing more waste heat to the heat exchange medium water. The circulating water discharged by the pulse automatic cleaning device 7 flows back to the cold water tank 5a, where it is recycled after sedimentation and filtration. This not only improves and reduces the turbidity of the circulating water, but also reduces the amount of wastewater discharged during the purification process.

[0039] The swirl atomizer 8 generates a high-kinetic-energy liquid phase fluid by controlling the internal flow field and circulation velocity distribution. An "L"-shaped air-assisted intake pipe is connected to its tangential inlet section, which helps to increase the nozzle outlet velocity as the inlet pressure increases along the tangential airflow. The droplets show a significant decreasing trend. The high-kinetic-energy liquid phase fluid increases the mixing intensity of water flow and airflow, enhances the turbulence of droplets, and makes the liquid film more unstable and more prone to rupture.

[0040] The low-temperature saturated wet flue gas at the top of purification tower 2 contains a large amount of dust and mist droplets. The cyclone demister 3 utilizes the collisions between a large number of particles of different sizes as they rise with the flue gas flow, as well as the impact of the mist droplets and fine ash particles on the blades under the action of the linear motion of the airflow. Under the action of the centrifugal force of the blades, the particles converge into liquid and flow back to the bottom of the tower under their own gravity. This achieves the capture and removal of dust and mist droplets in the flue gas, thereby achieving the separation and purification of flue gas, mist droplets, and dust. It has good environmental protection and economic performance. According to the "Determination of Low Concentration Particulate Matter in Exhaust Gas from Stationary Sources by Gravimetric Method" (HJ836-2017), particulate matter samples were taken and tested before and after the cyclone demister in the purification tower. According to the "Determination Method for Residual Droplets in the Exit Flue Gas of Wet Flue Gas Desulfurization Units" (JB / T10989-2010), the conductivity of condensate water before and after the demister was continuously tested, which proved that the cyclone demister has a higher capture efficiency for residual droplets in desulfurization slurry than the flat plate demister and the tube bundle demister.

[0041] The cleaning mechanism of the cyclone drainer 71 in the pulse automatic cleaning device 7 is as follows: water flows into the main cyclone cylinder 711 along the tangential direction. Under the action of centrifugal force and gravity, the mud and particulate impurities in it sink into the sludge accumulation area of ​​the main cyclone cylinder 711. After the water flow removes large particles of dirt, it still contains tiny particles and insoluble gases that are difficult to capture and remove. To further reduce the scouring, wear, and fouling of system pipes and valves caused by particulate matter in the water, as well as the cavitation of pump impellers caused by insoluble gases, and to reduce air-water impact accidents, an automatically operating deaerator 72 is connected in series after the cyclone separator 71. The deaerator 72, through air-water separation, spiral sedimentation, and precision filtration, causes insoluble gases to accumulate in the gas buffer zone at the top of the cylinder after entering the cylinder, and then be discharged through the pressure automatic exhaust valve 721. The deaerator 72 can effectively remove impurities larger than 5μm. The impurities agglomerate and settle in the fouling area at the bottom of the cylinder and are automatically discharged, reducing labor intensity and saving water resources.

[0042] The above provides a detailed description of the flue gas waste heat recovery and purification system provided by this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core idea of ​​this utility model. For those skilled in the art, the technical solution of this utility model is not limited to the solution defined in the specific embodiments. Technical solutions formed by other modifications that can be obviously implemented based on ordinary technical knowledge in the art are all within the protection scope of this utility model.

Claims

1. A flue gas waste heat recovery purification system, comprising a discharge device (1), a purification tower (2), a circulating water storage device (5), a heat pump unit (6) and a pulse automatic pollution removal device (7), the flue gas inlet at the bottom of the purification tower (2) is connected with the flue gas outlet of a boiler through a pipeline, the flue gas outlet at the top of the purification tower (2) is connected with the discharge device (1) through a pipeline, the circulating water storage device (5) comprises a cold water pool (5a) and a hot water pool (5b) which are isolated from each other, and is provided with a cold water pool water outlet (51), a cold water pool water inlet (52), a hot water pool water outlet (53) and a hot water pool water inlet (54); a spraying device (4) and a multi-stage cyclone mist eliminator (3) located above the spraying device (4) are arranged at the top of the purification tower (2), the water inlet of the spraying device (4) is connected with the cold water pool water outlet (51) through a pipeline and comprises a plurality of cyclone atomizers (8); characterized in that: the cyclone atomizer (8) comprises a cyclone atomizer shell (81), a cyclone passage (82), an airflow inlet (83), a liquid phase airflow pipeline (84), an atomized liquid outlet (85) and an airflow outlet (86); the water outlet at the bottom of the purification tower (2) is connected with the hot water pool water inlet (54) through a pipeline, the cold water pool water inlet (52) is connected with the water outlet of the heat pump unit (6) through a pipeline, and the hot water pool water outlet (53) is connected with the pulse automatic pollution removal device (7) through a pipeline; the pulse automatic pollution removal device (7) comprises a cyclone pollution removal device (71) and a degassing pollution removal device (72) which are connected in series; the cyclone mist eliminator (3) comprises a streamline guide pipe (31), a three-stage centrifugal separation guide vane (32) and a mist droplet collection separator (33). The cyclone atomizer shell (81) is annular, the liquid phase airflow pipeline (84) for receiving water flow from the cold water pool water outlet (51) is arranged in the tangential direction of the cyclone atomizer shell (81), an "L"-shaped air-assisted air inlet pipe is connected to the tangential inlet section of the cyclone atomizer shell (81), the airflow inlet (83) of the air-assisted air inlet pipe is perpendicular to the liquid phase airflow pipeline (84), the airflow outlet (86) of the air-assisted air inlet pipe is parallel to the axis of the liquid phase airflow pipeline (84), the atomized liquid outlet (85) is arranged on the lower surface of the cyclone atomizer shell (81), and the cyclone passage (82) is surrounded by the inner wall of the cyclone atomizer shell (81).

2. The flue gas heat recovery purification system according to claim 1, characterized by, The diameter of the cyclone atomizer shell (81) is 26-35 mm, and the diameter of the cyclone passage (82) is 8-12 mm.

3. The flue gas heat recovery scrubbing system of claim 2, wherein, ​ 4. The flue gas heat recovery scrubbing system of claim 1, wherein, The cyclone dirt discharger (71) comprises a main cyclone cylinder (711) and an eccentric screen cylinder (712), the main cyclone cylinder (711) comprises a water inlet (7111), an upper outlet (7112), a discharge port (7113) and an inspection port (7114), the water inlet (7111) is connected with the hot water pool outlet (53) through a pipeline, and the upper outlet (7112) is connected with the inlet of the degassing dirt discharger (72); the degassing dirt discharger (72) comprises a water outlet (723) and a pressure automatic exhaust valve (721), the water outlet (723) is connected with the water inlet of the heat pump unit (6) through a pipeline; the discharge port (7113) of the cyclone dirt discharger (71) and the degassing discharge port (722) of the degassing dirt discharger (72) are respectively connected with the cold water pool water inlet (52) through pipelines.

5. The flue gas heat recovery scrubbing system of claim 4, wherein, The eccentric angle of the eccentric screen cylinder (712) is 56-61°, the eccentric screen cylinder (712) adopts an assembled structure and is made of stainless steel, and the eccentric screen is umbrella-shaped.

6. The flue gas heat recovery scrubbing system of claim 5, wherein, The eccentric angle of the eccentric screen cylinder (712) is 58°.

7. The flue gas heat recovery scrubbing system of any one of claims 1-6, wherein, A circulating water pump is arranged on each pipeline.

8. The flue gas heat recovery scrubbing system of any one of claims 1-6, wherein, The circulating water storage device (5) adopts cold-heat partitioning and comprises a pool wall (9), a surface corrosion-resistant layer (93), a heat insulation layer (94) and a cold water pool (5a) and a hot water pool (5b) which are mutually isolated, an inner partition (91) is arranged between the cold water pool (5a) and the hot water pool (5b), and a balance overflow pipe (92) is left on the upper portion of the inner partition (91).

9. The flue gas heat recovery scrubbing system of any one of claims 1-6, wherein, The heat pump unit (6) is a corrosion-proof heat pump unit, which is connected with a heat network, and the water of the heat network returns to the heat network after heat exchange with the heat pump unit (6).

10. The flue gas heat recovery scrubbing system of claim 9, wherein, The heat pump unit (6) is an electric compression heat pump. The heat pump unit (6) is an electric compression heat pump.

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