Flue gas desulfurization and denitrification integrated treatment device

Abstract

The invention discloses a flue gas desulfurization and denitrification integrated treatment device, which comprises: a pretreatment unit, which comprises a pretreatment tank, a spiral guide plate, a cooler and a humidity regulator are sequentially arranged in the pretreatment tank from bottom to top, and the top of the pretreatment tank is sleeved with an annular water injection pipe, a plurality of branch pipes extending into the pretreatment tank are arranged on the annular water injection pipe at intervals, ultrasonic atomizers are arranged at the outlet ends of the branch pipes, a tail gas guide-in pipe is arranged on the side, close to the bottom, of the pretreatment tank, and a first exhaust pipe is arranged on the top of the pretreatment tank; the integrated reaction unit comprises a desulfurization reaction assembly connected with the first exhaust pipe and a denitration reaction assembly arranged at the rear end of the integrated reaction unit; the circulating separation unit comprises a separation tank connected with the gas outlet end of the denitration reaction assembly, and a wet dust removal assembly, a centrifugal separation assembly and a filter material assembly are sequentially arranged in the separation tank from bottom to top; according to the scheme, efficient purification of flue gas and cyclic utilization of resources are achieved through integrated design and a collaborative process.

Description

Technical Field

[0001] This invention relates to the field of flue gas emission treatment technology, specifically to an integrated flue gas desulfurization and denitrification treatment device. Background Technology

[0002] The pelletizing process in the steel industry generates a large amount of flue gas containing sulfides, nitrogen oxides, and dust particles. If this flue gas is emitted directly, it will cause serious pollution to the atmospheric environment, leading to environmental problems such as acid rain and smog. At the same time, it wastes recyclable resources in the flue gas, which is inconsistent with the development concept of green industry and resource recycling. Therefore, efficient desulfurization, denitrification, and dust removal treatment of pelletizing flue gas, and the realization of resource recycling, have become key issues that steel companies urgently need to solve.

[0003] Currently, dust treatment in pellet production mostly adopts a separate equipment and step-by-step approach, which has the following prominent problems: 1. Poor pretreatment effect: Traditional pretreatment cooling equipment mostly adopts a straight pipe cooling structure, resulting in short flue gas residence time and uneven cooling, which affects the stability of subsequent desulfurization and denitrification reactions. At the same time, traditional humidification methods mostly use spraying, which has poor water atomization effect and uneven flue gas humidification. This not only makes it difficult to achieve the ideal humidification and dust removal effect, but may also cause excessive moisture in the subsequent reaction system, affecting reaction efficiency. In addition, the slag discharge structure of traditional pretreatment equipment is complex and difficult to clean. Long-term use can easily lead to slag accumulation and blockage, affecting the continuous and stable operation of the equipment.

[0004] 2. Low desulfurization and denitrification efficiency: Existing technologies typically separate desulfurization and denitrification units, forming independent treatment systems. This separate approach not only requires a large land area and incurs high equipment investment costs, but also suffers from temperature drops and significant pressure losses during flue gas transport between the two units, resulting in low desulfurization and denitrification reaction efficiency. Furthermore, the desulfurizing agents commonly used in desulfurization and denitrification reactions are difficult to work synergistically, failing to fully utilize their treatment effects, leading to agent waste and increased operating costs for enterprises.

[0005] 3. Incomplete dust removal: Traditional dust removal equipment mostly uses single wet dust removal or filter media filtration methods. Single wet dust removal has poor capture effect on fine dust, low dust removal efficiency, and the generated dust-containing wastewater can easily cause secondary pollution if not properly treated; single filter media filtration dust removal suffers from problems such as easy clogging of filter media, high replacement frequency, and high maintenance costs.

[0006] 4. Low resource recycling rate: Solid particulate matter generated during desulfurization, denitrification and dust removal is mostly treated as waste and cannot be effectively recycled, which wastes resources and increases the cost of solid waste disposal.

[0007] 5. Insufficient system stability: Poor connectivity between processing units and lack of real-time control mechanisms make it difficult to adapt to fluctuations in flue gas parameters, resulting in unstable treatment effects and an inability to meet increasingly stringent environmental emission standards.

[0008] Therefore, there is an urgent need for an integrated device that combines pretreatment, desulfurization and denitrification, dust removal and resource recycling to improve processing efficiency, reduce costs and achieve green production. Summary of the Invention

[0009] To address the aforementioned shortcomings of existing technologies, this invention provides an integrated flue gas desulfurization and denitrification treatment device, which solves the problems of poor pretreatment effect, low desulfurization and denitrification efficiency, incomplete dust removal, and low resource recycling rate in current pellet production dust treatment technologies.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An integrated flue gas desulfurization and denitrification treatment device is provided, comprising: The pretreatment unit includes a pretreatment tank, in which a spiral guide plate, a cooler and a humidity controller are arranged sequentially from bottom to top. An annular water injection pipe is fitted on the top of the pretreatment tank, and several branch pipes extending into the pretreatment tank are arranged at intervals on the annular water injection pipe. An ultrasonic atomizer is installed at the outlet end of the branch pipe. An exhaust gas inlet pipe is installed on the side of the pretreatment tank near the bottom, and a first exhaust pipe is installed on the top of the pretreatment tank. An integrated reaction unit includes a desulfurization reaction assembly connected to the first exhaust pipe and a denitrification reaction assembly located at its rear end. The circulating separation unit includes a separation tank connected to the gas outlet of the denitrification reaction component. The separation tank contains, from bottom to top, a wet dust removal component, a centrifugal separation component, and a filter material component.

[0011] Furthermore, the cooler includes several fins, which are arranged vertically and spaced apart. Both ends of the fins are welded to the inner wall of the pretreatment tank. Water cooling coils are installed through the fins, and both ends of the water cooling coils are connected to the inlet and outlet of an external cold water circulation device. Aramid primary dust filter plates are installed at the upper end of the fins.

[0012] Furthermore, the exhaust gas inlet pipe is set horizontally, and the tangent at the connection between the exhaust gas inlet pipe and the pretreatment tank forms a 30-degree angle with the exhaust gas inlet pipe. The bottom of the pretreatment tank is detachably equipped with a slag discharge bottom plate.

[0013] Furthermore, the desulfurization reaction assembly includes a desulfurization chamber, in which flue gas guide plates are arranged alternately to form an S-shaped flue gas flow channel. At the bottom of the desulfurization chamber, there is an agitator propeller blade connected to the agitator motor. On the side of the desulfurization chamber, there is a feed valve pipe and a pH meter. At the top of the desulfurization chamber, there are several spray pipes with gaps, and several nozzles are arranged with gaps on the spray pipes. The spray pipes are connected to the bottom of the desulfurization chamber through a lift pump.

[0014] Furthermore, the denitrification reaction assembly includes a denitrification chamber located at the rear end of the desulfurization chamber. Several gas distribution baffles are arranged sequentially and intermittently within the denitrification chamber. Several vent holes are provided at the front end of the denitrification chamber and in the middle of the gas distribution baffles. Supported TiO2 activated carbon catalyst plates are provided on the side surfaces of the gas distribution baffles. Ultraviolet lamps are provided at the top and bottom of the denitrification chamber located on either side of the gas distribution baffles. An ammonia replenishment valve pipe is provided at the top of the denitrification chamber. A second exhaust pipe is provided at the rear end of the denitrification chamber.

[0015] Furthermore, the wet dust removal assembly includes a water guide pipe connected to several spray pipes, the water guide pipe being connected to the top of the separation tank, a second exhaust pipe extending into the separation tank and connected to a water collection pan, a number of vertical water distribution pipes being provided at the bottom of the water collection pan, and the lower end of the water distribution pipes being close to the bottom of the separation tank, the bottom of the separation tank being connected to the desulfurization chamber through a return pipe.

[0016] Furthermore, the filter material assembly includes a cap that is fixed to the top of the separation tank by bolts. The top of the cap is provided with an exhaust port. An integrally formed support is provided inside the cap. A conical aramid secondary dust filter plate is provided on the support. A limit ring is integrally formed on the upper surface of the support. A limit groove that engages with the limit ring is provided on the bottom edge of the aramid secondary dust filter plate.

[0017] Furthermore, the lower surface of the aramid secondary dust filter plate is provided with several inwardly recessed slag collection grooves.

[0018] Furthermore, the centrifugal separation component is fixed inside the tank cap with a centrifugal motor, which is equipped with several centrifugal fan blades. The separation tank located above the centrifugal fan blades is equipped with a barrier cover that works in conjunction with the centrifugal fan blades to achieve centrifugal dust removal.

[0019] Furthermore, the centrifugal fan blade is an L-shaped plate with an upward protrusion at the outer end, the baffle is ring-shaped, and the outer edge of the baffle is fixed to the inner wall of the separation tank. The inner edge of the baffle is smoothly bent downward, and an annular space is formed between the baffle and the inner wall of the separation tank to accommodate the protrusion at the outer end of the centrifugal fan blade. Several protrusions are evenly distributed on the inner wall of the separation tank around the centrifugal fan blade.

[0020] The beneficial effects of this invention are as follows: 1. The pretreatment unit of this solution extends the residence time of flue gas by 30%-50% through the design of 30-degree tangential air intake and spiral guide plate, and improves the uniformity of cooling, humidification and dust removal; the finned water cooling tube increases the contact area by 2-3 times, rapidly cools down and protects the subsequent catalytic materials; the ultrasonic atomizer precisely controls humidity (60%-70%), helps remove 20%-30% of fine particulate matter, and optimizes the subsequent reaction conditions.

[0021] 2. The desulfurization reaction assembly in this scheme adopts an "S"-shaped flow channel and overlapping spraying to increase the contact area between the ammonium sulfite solution and the flue gas, significantly improving the sulfur dioxide absorption efficiency. Through the linkage between the pH monitor and the ammonium sulfite feed valve, the pH value is maintained stable within the optimal reaction range of 6.5-7.5. With the stirring action of the stirring motor, stable desulfurization efficiency is ensured, reducing the sulfur dioxide emission concentration to below 35 mg / m³. The denitrification reaction assembly uses an ultraviolet light-catalyst synergistic system to reduce the activation energy of nitrogen oxides by 40%-50%. Precise control of ammonia gas through the ammonia supply valve ensures that nitric oxide and nitrogen dioxide are fully reduced to harmless nitrogen gas, avoiding secondary pollution caused by excessive ammonia. Parallel gas distribution baffles evenly distribute flue gas to the surface of each catalytic plate, preventing excessively high local flue gas concentrations that could lead to catalytic failure, reducing the nitrogen oxide emission concentration to below 50 mg / m³.

[0022] 3. The circulating separation unit of this scheme achieves deep purification of flue gas and dust through a three-stage synergy of wet dust removal, centrifugal dust removal, and filter media filtration, while also recycling and reusing the reagents and solid waste. During wet dust removal, ammonium sulfite solution is introduced into the separation tank through a water guide pipe, while a water distribution pipe disperses the flue gas into the liquid, allowing the liquid to capture fine particles from the flue gas. During centrifugal dust removal, a centrifugal motor drives centrifugal fan blades to blow flue gas towards a conical baffle. After the flue gas collides with evenly distributed protrusions, the microparticles and water mist are thrown towards the inner wall of the separation tank under the action of centrifugal force. During filter media filtration, the aramid secondary dust-proof filter plate can intercept ultrafine particles, and the slag collection tank on the lower surface collects dust. At the same time, the return pipe returns the liquid in the separation tank and the collected solid particles to the desulfurization chamber, realizing the recycling and reuse of reagents and solid waste. Furthermore, the solid particles can synergistically react with the ammonium sulfite solution in the desulfurization chamber, thereby further improving the desulfurization efficiency, reducing the consumption of ammonium sulfite solution, and reducing operating costs.

[0023] 4. This solution achieves high equipment integration through the integrated design of the pretreatment unit, integrated reaction unit, and circulating separation unit; each unit is directly connected by pipelines, reducing pressure loss during dust transport and fan energy consumption; at the same time, the modular structure facilitates disassembly and maintenance to adapt to production lines of different sizes. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The above and other objects, features, and advantages of the present invention will become clearer through the accompanying drawings. The same reference numerals indicate the same parts in all the drawings. The drawings are not intentionally drawn to scale to actual dimensions; the focus is on illustrating the main points of the invention.

[0025] Figure 1 This is a schematic diagram of the overall structure of an integrated flue gas desulfurization and denitrification treatment device.

[0026] Figure 2 This is a schematic diagram of the internal structure of an integrated flue gas desulfurization and denitrification treatment device.

[0027] Figure 3 for Figure 2 A magnified view of region A in the middle.

[0028] Among them, 100, pretreatment unit; 110, pretreatment tank; 120, exhaust gas inlet pipe; 130, spiral guide plate; 140, cooler; 141, fins; 142, water-cooled coil; 143, aramid primary dust filter plate; 150, slag discharge bottom plate; 160, humidity controller; 170, annular water injection pipe; 180, ultrasonic atomizer; 190, first exhaust pipe; 200, integrated reaction unit; 210, desulfurization reaction assembly; 211, desulfurization chamber; 212, flue gas guide plate; 213, stirring motor; 214, stirring propeller blade; 215, feed valve pipe; 216, pH meter; 217, booster pump; 218, spray pipe; 219, nozzle; 220, desulfurization... Nitrogenation reaction assembly; 221, Denitrification chamber; 222, Gas distribution baffle; 223, Supported TiO2 activated carbon catalyst plate; 224, Ultraviolet lamp tube; 225, Ammonia replenishment valve pipe; 226, Second exhaust pipe; 300, Circulation separation unit; 310, Separation tank; 320, Water guide pipe; 330, Return pipe; 340, Water collection tray; 350, Water distribution pipe; 360, Tank cap; 361, Exhaust port; 370, Filter media assembly; 371, Aramid secondary dust filter plate; 372, Replacement; 373, Limiting retainer ring; 374, Limiting retainer groove; 375, Slag collection tank; 380, Centrifugal separation assembly; 381, Centrifugal motor; 382, ​​Centrifugal fan blade; 383, Barrier cover; 384, Protrusion. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0033] like Figures 1 to 3 As shown, the integrated flue gas desulfurization and denitrification treatment device in this scheme includes: The pretreatment unit 100 includes a pretreatment tank 110. The pretreatment tank 110 is provided with a spiral guide plate 130, a cooler 140 and a humidity controller 160 arranged sequentially from bottom to top. The top of the pretreatment tank 110 is fitted with an annular water injection pipe 170, and several branch pipes extending into the pretreatment tank are arranged at intervals on the annular water injection pipe 170. An ultrasonic atomizer 180 is provided at the outlet end of the branch pipe. An exhaust gas inlet pipe 120 is provided on the side of the pretreatment tank 110 near the bottom. A first exhaust pipe 190 is provided on the top of the pretreatment tank 110. An integrated reaction unit includes a desulfurization reaction assembly 210 connected to a first exhaust pipe 190 and a denitrification reaction assembly 220 located at its rear end. The circulating separation unit includes a separation tank 310 connected to the gas outlet of the denitrification reaction component 220. The separation tank 310 contains, from bottom to top, a wet dust removal component, a centrifugal separation component 380, and a filter material component 370.

[0034] The cooler 140 in this scheme is used to cool the flue gas. The flue gas is humidified by the humidity controller 160, the annular water injection pipe 170 and the ultrasonic atomizer 180. At the same time, the humidified flue gas also comes into contact with large particles to achieve the purpose of dust removal. The pretreated flue gas is further treated by desulfurization reaction component 210 and denitrification reaction component 220. The circulating separation unit 300 achieves further dust removal and purification of flue gas by means of wet dust removal component, centrifugal separation component 380 for centrifugal dust removal and filter material component 370 for filtration dust removal arranged from bottom to top, and finally achieves the purpose of flue gas emission.

[0035] As an optional implementation, the cooler 140 includes a plurality of fins 141, which are vertically arranged and spaced apart. Both ends of the fins 141 are welded to the inner wall of the pretreatment tank 110. Water-cooled coils 142 are installed through the fins 141, and both ends of the water-cooled coils 142 are connected to the inlet and outlet of an external cold water circulation device. An aramid primary dust filter plate 143 is installed at the upper end of the fins 141. The exhaust gas inlet pipe 120 is horizontally arranged, and the tangent at the connection between the exhaust gas inlet pipe 120 and the pretreatment tank 110 forms a 30-degree angle with the exhaust gas inlet pipe 120. A slag discharge bottom plate 150 is detachably installed at the bottom of the pretreatment tank 110 for opening and removing slag after the equipment is stopped.

[0036] The pretreatment unit 100 of this scheme mainly includes the following functions: the exhaust gas inlet pipe 120 introduces air through a 30-degree tangential flow and, in conjunction with the spiral guide plate 130, creates a spiral upward flow field for the flue gas within the tank. Compared to the traditional direct-inlet method, the residence time of the flue gas in the pretreatment tank 110 is extended by 30%-50%, significantly improving the uniformity of cooling, humidification, and dust removal. The fins 141 in this scheme are used to increase the contact area between the water-cooled coil 142 and the flue gas, increasing the contact area by 2-3 times. This allows the water-cooled coil 142 to quickly reduce the high-temperature flue gas to a suitable reaction temperature, preventing high-temperature damage to subsequent catalysts. Materials: Aramid primary dust filter plate 143 is used for preliminary filtration of large particles in flue gas. It can intercept large particles with a diameter of ≥50μm. After pretreatment, the removal rate of large particles reaches more than 90%, thereby reducing the risk of slag accumulation and blockage in the subsequent desulfurization and denitrification system. Ultrasonic atomizer precisely humidifies the flue gas with water mist. With the help of humidity controller, the humidity of the flue gas is stabilized at 60%-70%. This avoids excessive humidity causing the flue gas to clump and block the flow channel. It can also help remove 20%-30% of fine particulate matter through the collision and adsorption of water mist and small particles of flue gas, while improving the liquid-gas contact efficiency in the subsequent desulfurization reaction.

[0037] As an optional implementation, the desulfurization reaction assembly 210 includes a desulfurization chamber 211, in which flue gas guide plates 212 are arranged alternately. At the bottom of the desulfurization chamber 211, there is a stirring propeller blade 214 that is driven and connected to the stirring motor 213. On the side of the desulfurization chamber 211, there is a feeding valve pipe 215 and a pH monitor 216. At the top of the desulfurization chamber 211, there are several spray pipes 218 arranged with gaps. At the spray pipes 218, there are several nozzles 219 arranged with gaps. The several spray pipes 218 are connected to the bottom of the desulfurization chamber 211 through a lift pump 217.

[0038] In this scheme, the desulfurization reaction component 210 replenishes ammonium sulfite solution to the bottom of the desulfurization chamber 211 during operation. The flue gas guide plate 212 is staggered in the desulfurization chamber 211 to form an S-shaped flue gas flow channel. The ammonium sulfite solution sprayed by several nozzles 219 fully contacts the flue gas in the S-shaped flue gas flow channel, thereby efficiently absorbing sulfur dioxide in the flue gas and achieving the purpose of desulfurization. The pH monitor 216 is used to monitor the acidity and alkalinity in the desulfurization chamber 211 and replenishes ammonium sulfite in the desulfurization chamber 211 in real time through the feed valve pipe 215 to avoid the pH value of the ammonium sulfite solution from becoming too low due to the absorption of sulfur dioxide. Specifically, when the pH value of the ammonium sulfite solution is lower than 5.5, it is automatically replenished to maintain the pH value stable in the optimal reaction range of 6.5-7.5. At the same time, the stirring motor 213 drives the stirring propeller blades 214 to stir the solution evenly, avoiding the local solution from becoming ineffective due to excessive absorption of sulfur dioxide, ensuring stable desulfurization efficiency, and ultimately reducing the sulfur dioxide emission concentration to below 35 mg / m³.

[0039] As an optional implementation, the denitrification reaction assembly 220 includes a denitrification chamber 221 located at the rear end of the desulfurization chamber 211. Several gas distribution baffles 222 are arranged sequentially and intermittently in the denitrification chamber 221. Several air vents are provided at the front end of the denitrification chamber 221 and in the middle of the gas distribution baffles 222. A supported TiO2 activated carbon catalyst plate 223 is provided on the side surface of the gas distribution baffles 222. Ultraviolet lamps 224 are provided at the top and bottom of the denitrification chamber 221 located on either side of the gas distribution baffles 222. An ammonia replenishment valve pipe 225 is provided at the top of the denitrification chamber 221. A second exhaust pipe 226 is provided at the rear end of the denitrification chamber 221.

[0040] The gas distribution baffle 222 in this scheme is used to distribute the flue gas entering the denitrification chamber 221, evenly distributing the flue gas dust to the surface of each TiO2 activated carbon catalyst plate 223, avoiding excessively high local flue gas dust concentration that could lead to catalytic failure. Under the synergistic effect of the ultraviolet light emitted by the ultraviolet lamp 224 and the supported TiO2 activated carbon catalyst plate 223, the activation energy of nitrogen oxides can be reduced by 40%-50%. Simultaneously, the ammonia supply is controlled by the ammonia supply valve 225, causing nitric oxide and nitrogen dioxide gases to undergo a reduction reaction with ammonia, converting them into harmless nitrogen gas, thus facilitating denitrification of the flue gas. Ultimately, the nitrogen oxide emission concentration can be reduced to below 50 mg / m³.

[0041] As an optional implementation, the wet dust removal assembly includes a water guide pipe 320 connected to several spray pipes 218. The water guide pipe 320 is connected to the top of the separation tank 310. A second exhaust pipe 226 extends into the separation tank 310 and is connected to a water collection tray 340. Several vertical water distribution pipes 350 are provided at the bottom of the water collection tray 340, and the lower end of the water distribution pipes 350 is close to the bottom of the separation tank 310. The bottom of the separation tank 310 is connected to the desulfurization chamber 211 through a return pipe 330. The water guide pipe 320 is used to carry the booster pump. The liquid lifted by the spray pipe 217 to the spray pipe 218 is introduced into the separator 310, while the return pipe 330 is used to return the liquid in the separator 310 to the desulfurization chamber 211. The second exhaust pipe 226 is used to inject the flue gas discharged from the denitrification reaction component 220 into the liquid at the bottom of the separator 310 through the water collection pan 340 and the water distribution pipe 350, so as to realize wet dust removal of flue gas. At the same time, it is also convenient for the dust falling off the centrifugal dust removal and filtration dust removal to be returned to the desulfurization reaction component 210 through the liquid, so as to realize the purpose of reagent recycling.

[0042] As an optional implementation, the filter media assembly 370 includes a cap 360 fixed to the top of the separation tank 310 by bolts. The top of the cap 360 has an exhaust port 361. An integrally formed support 372 is formed inside the cap 360. A conical aramid secondary dust filter plate 371 is provided on the support 372. A limiting ring 373 is integrally formed on the upper surface of the support 372. A limiting ring 373 is provided at the bottom edge of the aramid secondary dust filter plate 371 to engage with the limiting ring 373. The lower surface of the aramid secondary dust filter plate 371 is provided with several inwardly recessed slag collection grooves 375; the support 372 is used to support the aramid secondary dust filter plate 371, and the limiting retaining ring 373 and the limiting retaining groove 374 cooperate to increase the stability of the aramid secondary dust filter plate 371 installed above the support 372, while the slag collection grooves 375 increase the area of ​​the lower surface of the aramid secondary dust filter plate 371, which facilitates the aramid secondary dust filter plate 371 to filter flue gas.

[0043] As an optional implementation, the centrifugal separation assembly 380 is fixed inside the cap 360 with a centrifugal motor 381. The centrifugal motor 381 is provided with a plurality of centrifugal fan blades 382. The separation tank 310 located above the centrifugal fan blades 382 is provided with a barrier cover 383 that cooperates with the centrifugal fan blades 382 to achieve centrifugal dust removal.

[0044] The centrifugal fan blade 382 is an L-shaped plate with an upward protrusion at the outer end. The baffle 383 is annular, and its outer edge is fixed to the inner wall of the separation tank 310. The inner edge of the baffle 383 is smoothly bent downward. An annular space is formed between the baffle 383 and the inner wall of the separation tank 310 to accommodate the protrusion at the outer end of the centrifugal fan blade 382. Several protrusions 384 are evenly distributed on the inner wall of the separation tank 310 around the centrifugal fan blade 382. The centrifugal motor 381 blows the flue gas towards the inside of the baffle 383 through the centrifugal fan blade 382. At the same time, the flue gas entering and leaving the tank 383 collides with the protrusions 384, which facilitates the contact of water and dust in the flue gas with the inner wall of the separation tank 310 under the action of centrifugal force, thereby achieving the purpose of separating the flue gas from dust and water and realizing the purpose of centrifugal dust removal.

[0045] This solution also provides a treatment method for an integrated flue gas desulfurization and denitrification treatment device, which includes the following steps: 1. Smoke and dust pretreatment: The fumes generated during the purification chain loop-pellet production process are fed into the pretreatment tank 110 through the exhaust gas inlet pipe 120. The exhaust gas inlet pipe 120 is set at a 30-degree tangential angle with the lower side surface of the pretreatment tank 110. The fumes rise spirally under the guidance of the spiral guide plate 130 welded to the inner surface of the pretreatment tank 110. Simultaneously, the cooler 140 is activated. The cooler 140 includes fins 141 welded to the inner surface of the pretreatment tank 110 and water-cooled coils 142 penetrating the fins 141. Both ends of the water-cooled coils 142 pass through the fins 141 and are connected to the external cold water inlet and outlet respectively. Continuously flowing circulating cold water is introduced into the water-cooled coils 142. The fins 141 increase the pressure difference between the water-cooled coils 142 and the pretreatment tank 110. The contact area of ​​the flue gas is increased to achieve flue gas cooling. During the rising process, the flue gas undergoes preliminary filtration of large particles through the aramid primary dust filter plate 143 fixed on the upper surface of the water-cooling coil 142. The pore size of the aramid primary dust filter plate 143 is 50-100μm, allowing only flue gas particles with a diameter of less than 50μm to pass through. The annular water injection pipe 170 is activated, and water mist is sprayed into the pretreatment tank 110 through the ultrasonic atomizer 180 installed at its branch end. The humidity controller 160 monitors the humidity of the flue gas in the tank to achieve flue gas humidification. The humidified flue gas comes into contact with the unfiltered large particles to further assist in dust removal. After the equipment is shut down, the slag discharge bottom plate 150 installed at the bottom of the pretreatment tank 110 by bolts is opened to remove the slag accumulated in the tank.

[0046] The inlet temperature of the circulating cold water is controlled at 15-25℃, and the outlet temperature does not exceed 40℃. The inlet and outlet water temperatures of the water cooling coil 142 are monitored in real time by a temperature sensor. When the outlet water temperature exceeds 40℃, the cold water flow rate is automatically adjusted to maintain the cooling effect. The atomization volume of the ultrasonic atomizer 180 is 0.5-1.0L / h. The humidity controller 160 controls the humidity of the dust in the pretreatment tank 110 at 60%-70% to avoid dust agglomeration due to excessive humidity or the effect of auxiliary dust removal due to excessively low humidity.

[0047] 2. Integrated desulfurization and denitrification reaction: The pretreated flue gas enters the desulfurization chamber 211 of the desulfurization reaction assembly 210 through the first exhaust pipe 190. A staggered flue gas guide plate 212 is fixed inside the desulfurization chamber 211, forming an "S"-shaped flue gas flow channel. The booster pump 217 is activated to transport the ammonium sulfite solution in the desulfurization chamber 211 to the top of the chamber through a spray pipe 218. The solution is then sprayed out through nozzles 219 extending into the chamber from a branch of the spray pipe 218. The spray angle of the nozzles 219 is 120-150°, and the spray ranges of adjacent nozzles overlap to ensure adequate ammonium sulfite spray. Ammonium sulfite solution is evenly distributed in the "S"-shaped flue gas flow channel, with a contact area of ​​not less than 95% with the flue gas to fully absorb sulfur dioxide in the flue gas. At the same time, the stirring motor 213 is started, and the stirring propeller blades 214 fixed on its output shaft stir the ammonium sulfite solution at the bottom of the desulfurization chamber 211. The pH monitor 216 installed on the side surface of the desulfurization chamber 211 monitors the acidity and alkalinity of the solution in real time. When the pH value is lower than 5.5, the valve of the feed valve pipe 215 is automatically opened to replenish the ammonium sulfite solution into the desulfurization chamber 211 until the pH value rises back to 6.5-7.5. The desulfurized flue gas enters the denitrification chamber 221 of the denitrification reaction assembly 220. The denitrification chamber 221 contains 3-5 parallel gas distribution baffles 222 with centrally located vent holes. The spacing between adjacent gas distribution baffles 222 is 20-30 cm. The vent holes on the gas distribution baffles 222 have a diameter of 10-15 mm and an opening rate of 30%-40%. Supported TiO2 activated carbon catalyst plates 223 are mounted on the surface of the gas distribution baffles 222. The denitrification chamber 221 is then started. Ultraviolet lamps 224 are installed at the top and bottom. The wavelength of the ultraviolet lamps 224 is 254nm and the power is 30-50W. Ammonia gas is introduced into the denitrification chamber 221 through the ammonia gas supply valve pipe 225. The molar ratio of ammonia gas to nitrogen oxides in the flue gas is 1.2-1.5:1. Under the synergistic effect of ultraviolet light and the supported TiO2 activated carbon catalyst plate 223, nitric oxide and nitrogen dioxide in the flue gas undergo a reduction reaction with ammonia gas to be converted into nitrogen gas, thus completing the denitrification. Specifically, the stirring motor 213 rotates at 300-500 r / min, and the diameter of the stirring propeller blade 214 is 1 / 3-1 / 2 of the inner diameter of the desulfurization chamber 211 to ensure that the ammonium sulfite solution is stirred evenly. In step three, the liquid level in the separation tank 310 is maintained at 1 / 3-1 / 2 of the height of the separation tank 310. The liquid level is monitored in real time by a liquid level sensor. When the liquid level is lower than 1 / 3, ammonium sulfite solution is added through the water pipe 320. When the liquid level is higher than 1 / 2, the drain valve at the bottom of the separation tank 310 is opened to discharge excess liquid, ensuring stable wet dust removal and centrifugal dust removal effects.

[0048] 3. Circulating separation and reagent recovery: After denitrification, the flue gas enters the separation tank 310 of the circulating separation unit 300 through the second exhaust pipe 226, activating the wet dust removal component. The wet dust removal component includes a water guide pipe 320 extending from the spray pipe 218 and equipped with a flow control valve. The water guide pipe 320 introduces ammonium sulfite solution into the upper part of the separation tank 310 at a rate of 10%-15% / h of the liquid volume in the separation tank 310. At the same time, a water collection tray 340 is fixed to one end of the second exhaust pipe 226 that extends into the separation tank 310. A water distribution pipe 350 installed on the lower surface of the water collection tray 340 extends into the liquid stored at the bottom of the separation tank 310. The lower end of the water distribution pipe 350 is 5-10cm away from the bottom of the separation tank 310, and the water distribution pipe 350 has air outlet holes with a diameter of 2-3mm and an opening density of 20-30 holes / dm² to ensure that the flue gas is fully dispersed in the liquid to achieve wet dust removal. The centrifugal separation assembly 380 is started. The centrifugal separation assembly 380 includes a centrifugal motor 381 installed inside the tank cap 360. The speed of the centrifugal motor 381 is 1500-2000 r / min. The centrifugal fan blades 382 installed on its shell blow the flue gas toward the inside of the conical barrier 383 fixed on the inner surface of the separation tank 310. The cone angle of the barrier 383 is 60-90°. The flue gas collides with the protrusions 384 integrally formed on the inner surface of the upper end of the separation tank 310. There are 8-12 protrusions 384 evenly distributed, with a height of 5-8 mm and a width of 10-15 mm. Under the action of centrifugal force, the water and dust in the flue gas come into contact with the inner wall of the separation tank 310 to achieve centrifugal dust removal. Finally, the flue gas is filtered by the filter material assembly 370. The filter material assembly 370 includes an integrally formed support 372 inside the cap 360. The upper surface of the support 372 is provided with a conical aramid secondary dust filter plate 371. The pore size of the aramid secondary dust filter plate 371 is 1-5μm. The limiting groove 374 opened on the lower surface of its edge cooperates with the limiting ring 373 integrally formed on the upper surface of the support 372 for fixation. The lower surface of the aramid secondary dust filter plate 371 is recessed inward to form a slag collection groove 375 with a depth of 10-15mm and a width of 20-30mm to collect the dust generated during filtration. The flue gas meets the emission standards after being filtered by the aramid secondary dust filter plate 371. The reflux pipe 330 installed at the bottom of the separator 310 returns the liquid and collected solid particles in the tank to the desulfurization chamber 211. The reflux pipe 330 is equipped with a filter valve and a check valve with a filtration accuracy of 5-10μm to prevent large particles from entering the desulfurization chamber 211. The reflux rate of the liquid in the reflux pipe 330 is 5%-10% / h of the solution volume in the desulfurization chamber 211, ensuring the stability of the solution concentration in the desulfurization chamber 211 and realizing the recycling of reagents.

[0049] In summary, this solution achieves efficient flue gas purification and resource recycling through integrated design and synergistic processes. Optimized pretreatment, efficient "S-shaped flow channel" desulfurization and "ultraviolet catalytic" denitrification synergistic reactions, and three-stage deep dust removal via wet scrubbing, centrifugation, and filtration ultimately reduce the emission concentrations of sulfur dioxide, nitrogen oxides, and particulate matter to below 35 mg / m³, 50 mg / m³, and 10 mg / m³, respectively, far exceeding national standards. Simultaneously, the unique reagent recycling system reduces ammonium sulfite consumption by 40%-50%, significantly saving operating costs. The highly integrated system, combined with intelligent monitoring and control and a modular structure, ensures stable and reliable operation under various working conditions, providing a highly efficient, economical, compact, and adaptable integrated flue gas solution for pellet production.

[0050] Although the specific embodiments of the invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent; various modifications and variations that can be made by a person skilled in the art without inventive effort within the scope described in the claims are still within the scope of protection of this patent.

Claims

1. An integrated flue gas desulfurization and denitrification treatment device, characterized in that, include: The pretreatment unit (100) includes a pretreatment tank (110). The pretreatment tank (110) is provided with a spiral guide plate (130), a cooler (140) and a humidity controller (160) arranged sequentially from bottom to top. The top of the pretreatment tank (110) is fitted with an annular water injection pipe (170), and several branch pipes extending into the pretreatment tank are arranged at intervals on the annular water injection pipe (170). An ultrasonic atomizer (180) is provided at the outlet end of the branch pipe. An exhaust gas inlet pipe (120) is provided on the side of the pretreatment tank (110) near the bottom. A first exhaust pipe (190) is provided at the top of the pretreatment tank (110). An integrated reaction unit (200) includes a desulfurization reaction assembly (210) connected to a first exhaust pipe (190) and a denitrification reaction assembly (220) located at its rear end. The circulating separation unit (300) includes a separation tank (310) connected to the gas outlet of the denitrification reaction assembly (220), wherein a wet dust removal assembly, a centrifugal separation assembly (380) and a filter media assembly (370) are arranged sequentially from bottom to top inside the separation tank (310).

2. The integrated flue gas desulfurization and denitrification treatment device according to claim 1, characterized in that, The cooler (140) includes several fins (141), which are arranged vertically and spaced apart. Both ends of the fins (141) are welded to the inner wall of the pretreatment tank (110). A water-cooling coil (142) is provided through the fins (141), and both ends of the water-cooling coil (142) are connected to the inlet and outlet of an external cold water circulation device. An aramid primary dust filter plate (143) is provided at the upper end of the fins (141).

3. The integrated flue gas desulfurization and denitrification treatment device according to claim 1, characterized in that, The exhaust gas inlet pipe (120) is horizontally arranged, and the tangent at the connection between the exhaust gas inlet pipe (120) and the pretreatment tank (110) forms a 30-degree angle with the exhaust gas inlet pipe (120). The bottom of the pretreatment tank (110) is detachably provided with a slag discharge bottom plate (150).

4. The integrated flue gas desulfurization and denitrification treatment device according to claim 1, characterized in that, The desulfurization reaction assembly (210) includes a desulfurization chamber (211), in which flue gas guide plates (212) are arranged alternately to form an S-shaped flue gas flow channel. At the bottom of the desulfurization chamber (211) is a stirring propeller blade (214) that is driven and connected to a stirring motor (213). On the side of the desulfurization chamber (211) are a feeding valve pipe (215) and a pH meter (216). At the top of the desulfurization chamber (211) are several spray pipes (218) with gaps. At the spray pipes (218) are several nozzles (219) with gaps. Several spray pipes (218) are connected to the bottom of the desulfurization chamber (211) through a lift pump (217).

5. The integrated flue gas desulfurization and denitrification treatment device according to claim 4, characterized in that, The denitrification reaction assembly (220) includes a denitrification chamber (221) located at the rear end of the desulfurization chamber (211). Several gas distribution baffles (222) are arranged sequentially and intermittently in the denitrification chamber (221). Several air vents are provided at the front end of the denitrification chamber (221) and the middle of the gas distribution baffles (222). A supported TiO2 activated carbon catalyst plate (223) is provided on the side surface of the gas distribution baffles (222). Ultraviolet lamp tubes (224) are provided at the top and bottom of the denitrification chamber (221) located on either side of the gas distribution baffles (222). An ammonia replenishment valve pipe (225) is provided at the top of the denitrification chamber (221). A second exhaust pipe (226) is provided at the rear end of the denitrification chamber (221).

6. The integrated flue gas desulfurization and denitrification treatment device according to claim 5, characterized in that, The wet dust removal assembly includes a water guide pipe (320) connected to several spray pipes (218). The water guide pipe (320) is connected to the top of the separation tank (310). The second exhaust pipe (226) extends into the separation tank (310) and is connected to the water collection tray (340). Several vertical water distribution pipes (350) are provided at the bottom of the water collection tray (340), and the lower end of the water distribution pipes (350) is close to the bottom of the separation tank (310). The bottom of the separation tank (310) is connected to the desulfurization chamber (211) through a return pipe (330).

7. The integrated flue gas desulfurization and denitrification treatment device according to claim 1, characterized in that, The filter media assembly (370) includes a cap (360) fixed to the top of the separation tank (310) by bolts. The top of the cap (360) is provided with an exhaust port (361). A support (372) is integrally formed inside the cap (360). A conical aramid secondary dust filter plate (371) is provided on the support (372). A limiting ring (373) is integrally formed on the upper surface of the support (372). A limiting groove (374) that engages with the limiting ring (373) is opened at the bottom edge of the aramid secondary dust filter plate (371).

8. The integrated flue gas desulfurization and denitrification treatment device according to claim 7, characterized in that, The lower surface of the aramid secondary dust filter plate (371) is provided with several inwardly recessed slag collection grooves (375).

9. The integrated flue gas desulfurization and denitrification treatment device according to claim 7, characterized in that, The centrifugal separation component (380) is fixed inside the centrifugal motor (381) in the tank cap (360). The centrifugal motor (381) is provided with a plurality of centrifugal fan blades (382). The separation tank (310) located above the centrifugal fan blades (382) is provided with a barrier cover (383) that cooperates with the centrifugal fan blades (382) to achieve centrifugal dust removal.

10. The integrated flue gas desulfurization and denitrification treatment device according to claim 9, characterized in that, The centrifugal fan blade (382) is an L-shaped plate with an upward protrusion at the outer end. The barrier cover (383) is annular in shape, and the outer edge of the barrier cover (383) is fixed to the inner wall of the separation tank (310). The inner edge of the barrier cover (383) is smoothly bent downward. An annular space is formed between the barrier cover (383) and the inner wall of the separation tank (310) to accommodate the protrusion at the outer end of the centrifugal fan blade (382). Several protrusions (384) are evenly distributed on the inner wall of the separation tank (310) around the centrifugal fan blade (382).

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