Centrifugal force type purification system for treating flue gas and flue gas purification method

Abstract

The invention relates to a centrifugal force type purification system for treating flue gas and a flue gas purification method. The centrifugal force type purification system comprises a flue gas storage tank, a pretreatment unit, an E-RPB reaction unit, a post-treatment unit, a recovery unit and a cleaning unit, the flue gas storage tank is connected with the pretreatment unit and is used for performing dust removal, heat exchange and humidity adjustment on flue gas; the pretreatment unit is connected with the E-RPB reaction unit and is used for desulfurizing flue gas; the E-RPB reaction unit is respectively connected with the post-treatment unit, the recovery unit and the cleaning unit, and is used for discharging desulfurized clean flue gas, recycling waste liquid generated after flue gas desulfurization and cleaning the E-RPB reaction unit. The system realizes efficient removal of SO2 in flue gas under a centrifugal force field through the design of gas-liquid co-flowing and rotating three-layer staggered grid filler layers, and is particularly suitable for high-sulfur flue gas treatment scenes such as coal-fired power plants and steel sintering. According to the flue gas purification method, the desulfurization efficiency is improved in a breakthrough manner, and the desulfurization rate is gt; 98%; low pressure drop and energy conservation are realized.

Description

Technical Field

[0001] This invention relates to the field of industrial flue gas treatment technology, specifically to a centrifugal purification system and method for treating flue gas. Background Technology

[0002] Flue gas desulfurization (FGD) technology has undergone several iterations since the mid-20th century, mainly falling into three categories: wet, semi-dry, and dry methods. Early wet FGD methods (such as the limestone-gypsum method) relied on large spray towers or packed towers, with equipment heights generally exceeding 20 meters and mass transfer coefficients of only 0.01-0.1 s⁻¹. -1 The liquid-to-gas ratio (L / G) is as high as 8-15 L / m³. 3 This leads to high operating costs. Since the 1990s, semi-dry methods (such as spray drying) and dry methods (such as activated carbon adsorption) have gradually developed, but they still face problems such as low desulfurization efficiency (usually <90%) and easy equipment blockage.

[0003] Existing desulfurization systems still suffer from the following bottlenecks: Low mass transfer efficiency: Spray towers rely on gravity, resulting in short contact time between droplets and flue gas. The SO2 absorption rate in the flue gas is limited by the laminar boundary layer, leading to a desulfurization rate of only 85%-90%. Large desulfurization equipment: Traditional towers exceed 20 meters in height and occupy 300-500 square meters of space. 2 Infrastructure costs account for over 40%. Equipment energy consumption and clogging issues: Although multi-layer packing increases the mass transfer area, the pressure drop exceeds 500Pa, increasing fan energy consumption by 40%; at the same time, sulfur or gypsum deposits easily clog the packing, leading to reduced operating efficiency. Poor adaptability: High-sulfur flue gas or high-viscosity slurry (such as lime slurry) easily leads to flooding, causing a sharp drop in desulfurization rate.

[0004] To address the above technical issues, a centrifugal purification system and method for treating flue gas are proposed. Summary of the Invention

[0005] This invention provides a centrifugal purification system for treating flue gas. The system uses a three-layer interlaced grid packing design with gas-liquid co-flow and rotation to achieve efficient removal of SO2 from flue gas under centrifugal force, and is particularly suitable for high-sulfur flue gas treatment scenarios such as coal-fired power plants and steel sintering.

[0006] This invention provides a flue gas purification method for a centrifugal purification system for treating flue gas, which achieves a breakthrough improvement in desulfurization efficiency, with a desulfurization rate of >98%; and low pressure drop and energy saving.

[0007] The technical problem solved by this invention is achieved through the following technical solution: A centrifugal purification system for treating flue gas includes a flue gas storage tank, a pretreatment unit, an E-RPB reaction unit, a post-treatment unit, a recovery unit, and a cleaning unit. The flue gas storage tank is connected to the pretreatment unit for dust removal, heat exchange, and humidity regulation of the flue gas. The pretreatment unit is connected to the E-RPB reaction unit for desulfurization of the flue gas. The E-RPB reaction unit is connected to the post-treatment unit, the recovery unit, and the cleaning unit to discharge the cleaned flue gas after desulfurization, recycle and reuse the waste liquid generated after flue gas desulfurization, and clean the E-RPB reaction unit. The pretreatment unit includes an electrostatic precipitator, a heat exchanger, and a humidity regulator. The E-RPB reaction unit includes an outer cavity, an exhaust port and a liquid outlet located on the left side of the outer cavity, a gas inlet located at the top of the outer cavity, an annular liquid inlet pipe located on the side of the outer cavity, an adsorbent storage tank connected to the annular liquid inlet pipe, a mesh packing layer located inside the outer cavity, and a rotor installed at the center of the mesh packing layer. The post-treatment unit includes a baffle demister connected to the exhaust port and an activated carbon adsorption tower connected to the baffle demister. The recycling unit includes a neutralization tank connected to the drain outlet and a lime slurry tank connected to the neutralization tank; The cleaning unit includes a citric acid solution storage tank connected to the E-RPB reaction unit; The rotating three-layer staggered mesh packing layer includes an upper packing layer, a middle packing layer, and a lower packing layer; the upper packing layer is the initial high-efficiency dissolution zone; the middle packing layer is the turbulence-enhanced mass transfer zone; and the lower packing layer is the reaction completion zone.

[0008] Furthermore, the electrostatic precipitator connected to the flue gas storage tank has an electrode spacing of 200mm, an operating voltage of 50-80kV, removes particles >10μm from the flue gas, and has an outlet dust content ≤30mg / m³. 3 The heat exchanger is connected to the electrostatic precipitator, and the heat exchanger is a shell-and-tube heat exchanger with a heat exchange area of ​​60 m². 2 The cooling medium is circulating water, which cools the flue gas from 140-180℃ to 50-70℃; the humidity regulator is connected to the heat exchanger and is a steam jet humidity regulator with a steam pressure of 0.3-0.5MPa, which adjusts the flue gas humidity to 60%-80%.

[0009] Furthermore, the outer cavity is a cylindrical outer cavity with a diameter of 1000mm and a height of 810mm, made of 316L stainless steel, and pressure-resistant to 0.4MPa; the annular inlet pipe evenly distributes several atomizing nozzles, with 6-8 atomizing nozzles, each having a swirl core structure, an inlet pressure of 0.4-0.6MPa, flow fluctuation ≤±5%, atomized particle size of 80-150μm, and a built-in self-cleaning needle valve with a backwashing cycle of 24 hours; the mesh wire diameter of the rotating three-layer staggered mesh packing layer is 0.35mm±0.05mm, and the interlayer spacing is 20mm±2mm; short-flow prevention baffles are provided between adjacent mesh layers, with a height of 10mm and a thickness of 2mm; the mesh material of the upper packing layer is 304 stainless steel; the mesh material of the middle packing layer is 316 stainless steel; and the mesh material of the lower packing layer is 304 stainless steel. Furthermore, the rotor's shaft is coaxial with the center of the outer cavity, the rotor power is 15kW, and the rotation speed is 300-900r / min; the rotor is driven to rotate and the rotor shaft temperature is detected by a frequency conversion drive system and a bearing temperature detection system, respectively; the frequency conversion drive system has a speed adjustment response time of ≤3 seconds, and the bearing temperature detection system is set with an over-temperature threshold of 80℃.

[0010] Furthermore, it also includes an ultrasonic level sensor connected to the outer cavity, used to monitor the amount of waste liquid deposited at the bottom of the cavity after desulfurization by the E-RPB reaction unit.

[0011] Furthermore, the baffle demister has a plate spacing of 22mm to remove entrained droplets; the activated carbon adsorption tower has a loading capacity of 250kg.

[0012] Furthermore, the neutralization tank is equipped with an online pH probe with a range of 0-14 and an accuracy of ±0.1. The neutralization tank uses a clear liquid recycling pipeline to reuse the clear liquid neutralized by lime slurry from the waste liquid after desulfurization of the E-RPB reaction unit to the adsorbent storage tank, with a recycling rate of 40%.

[0013] A flue gas purification method for a centrifugal purification system for treating flue gas includes the following steps: S1. Flue gas pretreatment: The flue gas to be treated is injected into the flue gas storage tank, and after electrostatic dust removal by an electrostatic precipitator, the dust content inside the gas is reduced to 30 mg / m³. 3 Next, the gas temperature is reduced to 60±5℃ by passing through a shell-and-tube heat exchanger to prevent droplet evaporation caused by high temperature; the flue gas humidity is then adjusted to RH 70±5% by a steam jet humidity regulator. S2, Centrifugal Force Field Enhanced Desulfurization: The pretreated flue gas enters the E-RPB reaction unit from the gas inlet at a tangential velocity of 6.0±0.5m / s; 15%-20% NaOH solution is sprayed into the rotating three-layer staggered grid packing layer through the atomizing nozzle of the annular liquid inlet pipe at a velocity of 2.0±0.2m / s; desulfurization is carried out through the E-RPB reaction unit; S3. Gas-liquid purification and separation: After desulfurization in the E-RPB reaction unit, the gas from centrifugal force-enhanced desulfurization passes through a baffle demister at the exhaust port to remove droplets. The gas then enters an activated carbon adsorption tower to remove residual heavy metals, with Hg and As removal rates >95%. The SO2 concentration in the flue gas is measured at the gas exhaust outlet of the activated carbon adsorption tower, meeting the standard of SO2 ≤ 35 mg / m³. 3 The clean gas is then discharged. S4. Waste liquid recovery: The NaOH waste liquid containing Na2SO3, after desulfurization in the E-RPB reaction unit, flows from the discharge port to the neutralization tank. Lime slurry from the lime slurry tank is added to the NaOH waste liquid containing Na2SO3 in the neutralization tank for neutralization. This neutralization reaction uses a wet flue gas desulfurization process with lime slurry precipitation and regeneration. The formula is: , After neutralization, 40% NaOH clear liquid is collected and reused in the adsorbent storage tank. The recovered 40% NaOH clear liquid is recycled for the desulfurization process, reducing NaOH consumption. Online cleaning of S5 and E-RPB reaction units: Every 72 hours of operation, the E-RPB reactor unit will undergo an online cleaning procedure: the gas inlet is closed, and the rotor speed is maintained at 200 r / min; 2% citric acid solution is sprayed into the E-RPB reactor unit through the atomizing nozzle of the annular liquid inlet pipe to rinse the rotating three-layer interlaced grid packing layer for 30 minutes, i.e., the citric acid absorption method; the waste liquid after cleaning is discharged through the drain port. S6. Repeat S1-S5 to purify the flue gas.

[0014] Furthermore, in step S3, the activated carbon adsorption tower is regenerated by hot nitrogen purging. Saturated activated carbon can be regenerated by water washing or heating. The nitrogen temperature is controlled at 180℃±10℃, and the flow rate is 500-800 m³ / h. 3 / h; purge time 4-6 hours, adsorption capacity recovery ≥95% after regeneration.

[0015] The advantages and positive effects of this invention are: 1. The centrifugal purification system for treating flue gas of the present invention achieves efficient removal of SO2 from flue gas under centrifugal force field through the design of a three-layer grid packing layer with gas-liquid co-flow and rotation. It is especially suitable for high-sulfur flue gas treatment scenarios such as coal-fired power plants and steel sintering.

[0016] 2. The flue gas purification method of the centrifugal purification system of this invention involves flue gas entering the E-RPB reaction unit in the same direction after passing through the pretreatment unit and the adsorbent clarified liquid. Its core advantage lies in avoiding the flooding phenomenon that easily occurs in traditional countercurrent operations. The relative velocity and shear force between the gas and liquid phases are significantly reduced, creating a stable high liquid holdup reaction environment. This stability allows the liquid to form a more uniformly distributed liquid film or filament within the packing layer, with a more controllable residence time, providing a continuous and stable contact interface for rapid chemical reactions within the reaction unit. Experiments show that at speeds of 300 to 900 r / min, the gas and liquid undergo a staged reaction through a rotating three-layer staggered mesh packing layer for 6-8 seconds, achieving a desulfurization rate >98% (compared to only 85-90% in traditional technologies), a 3-fold increase in SO2 mass transfer efficiency in the flue gas, and a breakthrough improvement in desulfurization efficiency.

[0017] 3. The flue gas purification method of the centrifugal purification system of the present invention can achieve a centrifugal acceleration of up to 200-300g through the rotor, which extends the residence time of liquid droplets inside the outer cavity to 6-8 seconds (compared to only 2 seconds in traditional RPB). This solves the problems of short reaction time and high pressure drop in traditional rotating beds. The height is reduced by more than 90% compared to the original desulfurization tower, which significantly reduces energy consumption and operating costs, reduces the pressure drop to 140Pa (compared to 3.2kPa in traditional spray towers), and reduces the energy consumption of the fan by 35%.

[0018] 4. The flue gas purification method of the centrifugal purification system for treating flue gas of the present invention optimizes the packing structure (porosity 0.92) to reduce the pressure drop to 140Pa, reduce energy consumption by 35%, and save energy with low pressure drop.

[0019] 5. The flue gas purification method of the centrifugal purification system for treating flue gas of the present invention features an anti-clogging design, liquid inlet in the outer cavity to avoid sulfur deposition, and online citric acid cleaning, which significantly increases the continuous operation time.

[0020] 6. The centrifugal purification system and method for treating flue gas of this invention improves the ability to resist clogging and operate for a long period of time. The liquid inlet in the outer cavity avoids sulfur deposition, and the three-layer rotating interlaced grid packing layer inside the outer cavity guides the flow field and eliminates dead corners. Through online citric acid cleaning (2% solution, 60°C), it can run continuously for 8000 hours without clogging (traditional packed towers need to be shut down for cleaning every 2000 hours). Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the centrifugal purification system for treating flue gas according to the present invention. Figure 2 This is a graph showing the relationship between the number of mesh packing layers and the desulfurization rate in the centrifugal purification system for treating flue gas according to the present invention. Figure 3This is a graph showing the relationship between the rotor shaft speed and pressure drop in the centrifugal purification system for treating flue gas according to the present invention. Figure 4 This is a graph showing the relationship between the rotor shaft speed and the residence time of the internal absorbent droplets in the centrifugal purification system for treating flue gas according to the present invention. In the picture: 1-Flue gas storage tank, 2-Electrostatic precipitator, 3-Heat exchanger, 4-Humidity regulator, 5-Gas inlet, 6-Outer cavity, 7-Grid packing layer, 8-Rotor, 9-Liquid inlet pipe, 10-Drain outlet, 11-Exhaust outlet, 12-Adsorbent storage tank, 13-Activated carbon adsorption tower, 14-Baffle plate demister, 15-Lime slurry tank, 16-Neutralization tank, 17-Clear liquid reuse pipeline, 18-Citrate solution storage tank, 19-Ultrasonic liquid level sensor, 20-Variable frequency drive system, 21-Bearing temperature detection system, 22-pH online probe. Detailed Implementation

[0022] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0023] like Figure 1 As shown, a centrifugal purification system for treating flue gas includes a flue gas storage tank 1, a pretreatment unit, an E-RPB (centrifugal rotating packed bed) reaction unit, a post-treatment unit, a recovery unit, and a cleaning unit. The flue gas storage tank 1 is connected to the pretreatment unit for dust removal, heat exchange, and humidity regulation of the flue gas. The pretreatment unit is connected to the E-RPB reaction unit for desulfurization of the flue gas. The E-RPB reaction unit is connected to the post-treatment unit, the recovery unit, and the cleaning unit to discharge the cleaned flue gas after desulfurization, recycle and reuse the waste liquid generated after flue gas desulfurization, and clean the E-RPB reaction unit. The innovatively designed waste liquid recovery system achieves resource recycling, while the intelligent cleaning unit ensures long-term stable operation of the equipment through regular online maintenance. This end-to-end design not only forms a complete closed-loop solution but also offers operational flexibility and engineering adaptability, significantly reducing the total life-cycle cost while ensuring ultra-clean emissions, demonstrating excellent industrial application value.

[0024] The pretreatment unit includes an electrostatic precipitator 2 connected to the flue gas storage tank 1, with an electrode spacing of 200mm, an operating voltage of 50-80kV, and a selected operating voltage of 70kV. It removes particles >10μm from the flue gas, achieving an outlet dust content ≤30mg / m³. 3 Heat exchanger 3 is connected to electrostatic precipitator 2. Heat exchanger 3 is a shell-and-tube heat exchanger with a heat exchange area of ​​60 m². 2The cooling medium is circulating water, which cools the flue gas from 140-180℃ to 50-70℃ to prevent droplet evaporation. The humidity regulator 4 is connected to the heat exchanger 3. The humidity regulator 4 is a steam jet type humidity regulator 4 with a steam pressure of 0.3-0.5MPa, which adjusts the humidity of the flue gas to 60%-80% to enhance the SO2 dissolution efficiency in the flue gas.

[0025] The E-RPB reaction unit includes an outer cavity 6, which is a cylindrical outer cavity 6 with a diameter of 1000mm, a height of 810mm, and is made of 316L stainless steel with a pressure resistance of 0.4MPa. Gas inlet 5 is located at the top of the outer cavity 6; exhaust port 11 and liquid outlet 10 are located on the left side of the outer cavity 6; A number of atomizing nozzles are evenly distributed on the annular liquid inlet pipe 9 on the side of the outer cavity 6. There are 6-8 atomizing nozzles. The atomizing nozzles have a swirl core structure. The inlet pressure of the atomizing nozzles is 0.4-0.6MPa, the flow rate fluctuation is ≤±5%, and the atomized particle size is 80-150μm. The atomizing nozzles have built-in self-cleaning needle valves, and the backwashing cycle of the cleaning fluid is 24 hours. The adsorbent storage tank 12 is connected to the annular inlet pipe 9. The adsorbent liquid in the adsorbent storage tank 12 is injected into the annular inlet pipe 9 and sprayed with 15%-20% NaOH solution through the atomizing nozzle. The rotating three-layer staggered mesh packing layer 7 located inside the outer cavity 6 includes an upper packing layer, which is the initial high-efficiency dissolution zone, and its mesh material is 304 stainless steel; a middle packing layer, which is the turbulence-enhanced mass transfer zone, and its mesh material is 316 stainless steel; and a lower packing layer, which is the reaction completion zone, and its mesh material is 304 stainless steel. The mesh wire diameter of the rotating three-layer staggered mesh packing layer 7 is 0.35mm±0.05mm, and the interlayer spacing is 20mm±2mm. Short-flow prevention baffles are provided between adjacent mesh layers, with a height of 10mm and a thickness of 2mm.

[0026] A rotor 8 is mounted at the center of a rotating three-layered, staggered mesh packing layer 7. The axis of rotor 8 is coaxial with the center of the outer cavity 6. Rotor 8 has a power of 15kW and a rotation speed of 300-900 r / min. A variable frequency drive system 20 and a bearing temperature detection system 21 drive rotor 8 to rotate and detect the rotor shaft temperature to prevent overheating and provide safety protection for the purification process. The variable frequency drive system 20 has a speed adjustment response time of ≤3 seconds, and the bearing temperature detection system 21 has an over-temperature threshold of 80℃.

[0027] An ultrasonic liquid level sensor 19, installed on the left side of the outer cavity 6, is used to monitor the amount of waste liquid after desulfurization by the E-RPB reaction unit in real time.

[0028] The post-treatment unit includes a baffle demister 14 connected to the exhaust port 11 with a plate spacing of 22 mm to remove entrained droplets (particle size > 5 μm); and an activated carbon adsorption tower 13 connected to the baffle demister 14 with a loading of 250 kg to remove residual heavy metals.

[0029] The recovery unit includes a neutralization tank 16 connected to the drain outlet 10 and a lime slurry tank 15 connected to the neutralization tank 16. The drain outlet 10 is connected to the waste liquid neutralization tank 16, and an online pH probe 22 is installed in the neutralization tank 16 with a range of 0-14 and an accuracy of ±0.1. The neutralization tank 16 is connected to the lime slurry tank 15. The neutralization tank 16 uses a clear liquid reuse pipeline 17 to reuse the neutralized clear liquid from the desulfurization of the E-RPB reaction unit to the adsorbent storage tank 12, with a reuse rate of 40%.

[0030] The cleaning unit includes a citric acid solution storage tank 18 connected to the E-RPB reaction unit. The citric acid solution in the citric acid solution storage tank 18 is injected into the E-RPB reaction unit to clean it.

[0031] like Figures 1 to 4 As shown, a flue gas purification method for a centrifugal purification system for treating flue gas is described: S1. Flue gas pretreatment: Flue gas to be treated (SO2 concentration 2000-3500 mg / m³) 3 The flue gas is injected into the storage tank 1 and then electrostatically removed by the electrostatic precipitator 2, reducing the dust content inside the gas to 30 mg / m³. 3 Next, the gas temperature is reduced to 60±5℃ by passing through the shell-and-tube heat exchanger 3 to prevent droplet evaporation caused by high temperature; the flue gas humidity is adjusted to RH70±5% by the steam jet humidity regulator 4 to enhance the droplet's ability to capture SO2. S2, Centrifugal Force Field Enhanced Desulfurization: Pretreated flue gas enters the E-RPB reaction unit from gas inlet 5 at a tangential velocity of 6.0±0.5m / s; 15%-20% NaOH solution is sprayed into the rotating three-layer staggered mesh packing layer 7 through the atomizing nozzle of the annular liquid inlet pipe 9 at a velocity of 2.0±0.2m / s; desulfurization is carried out through the E-RPB reaction unit; the rotating three-layer staggered mesh packing layer 7 optimizes the desulfurization process by creating a differentiated flow field environment.

[0032] The upper packing layer serves as the initial high-efficiency contact zone, representing the first large-scale contact area between fresh alkaline solution and high-concentration flue gas. Due to the maximum mass transfer driving force here, SO2 reacts rapidly with NaOH (SO2 + 2NaOH → Na2SO3 + H2O), exhibiting the fastest reaction rate. During stable operation of the centrifugal purification system treating flue gas, the initial high-efficiency contact zone can remove 40% of the total sulfur-containing waste gas load.

[0033] The middle packing layer, serving as the turbulence-enhanced mass transfer zone, functions primarily to generate intense micro-turbulence and vortices (turbulence intensity ≥ 0.25, Reynolds number Re > 5000), continuously disrupting and renewing the existing concentration boundary layer. This increases the volumetric mass transfer coefficient of the centrifugal purification system for flue gas treatment to 1.25 s⁻¹. -1 This significantly increases the cumulative desulfurization rate to approximately 85%.

[0034] The lower packing layer, serving as the reaction completion zone, focuses on the final stage of the reaction. The remaining sulfur-containing waste gas undergoes its final reaction with the alkaline solution here, while simultaneously guiding the waste liquid smoothly and rapidly towards the chamber wall under strong centrifugal force. The liquid holdup in the reaction completion zone is successfully controlled below 5%, effectively preventing waste liquid stagnation and thus freeing up space for the continuous replenishment of fresh liquid in the initial high-efficiency contact zone, ensuring the continuity of efficient mass transfer throughout the entire system.

[0035] like Figure 2 As shown: When the number of packing layers is increased to 4 or 5 layers with the same gap, flooding occurs during the operation of the reaction unit, the reaction process is hindered, and the reaction efficiency decreases. Therefore, the equipment adopts a three-layer mesh packing.

[0036] like Figure 3 As shown, within the operating range of 300-900 r / min, as the rotational speed increases, the internal pressure drop also gradually increases, and the system energy consumption gradually increases.

[0037] like Figure 4 As shown: Within the operating range of 300-900 r / min, increasing the rotational speed prolongs the residence time of the NaOH absorbent droplets inside. The core reason lies in the flow pattern transformation: when the rotational speed increases, the strong centrifugal force significantly increases the turbulence of the gas-liquid flow field inside the reaction unit. Simultaneously, it forces the droplet particles to undergo a more tortuous and prolonged meandering motion along the packing channels, thus increasing the residence time.

[0038] During operation, the rotor speed should be reasonably controlled to ensure the reaction unit operates under safe and reasonable conditions. The dynamic speed control of the rotating three-layer staggered mesh packing layer 7, and the rotor speed adjustment formula, are as follows: n=k·Q g 0.5 (k=16±1), Where Qg is the flue gas volumetric flow rate (m³ / s). 3 / h), when SO2 concentration is greater than 2000 mg / m 3 At this time, k is increased to 17.5 to enhance mass transfer, where k is a dimensionless process adjustment coefficient. The value of k dynamically correlates the flue gas volume flow rate with the rotor speed to ensure that the centrifugal force field strength matches the mass transfer requirements under different operating conditions.

[0039] When the SO2 concentration in the flue gas is >2000 mg / m³ 3 When the pressure drop is greater than 150Pa, the speed reduction protection is triggered (reduction of 10%-20%).

[0040] S3. Gas-liquid purification and separation: After desulfurization in the E-RPB reaction unit, the gas from centrifugal force-enhanced desulfurization passes through exhaust port 11 and baffle demister 14 to remove droplets. The gas then enters activated carbon adsorption tower 13 to remove residual heavy metals (Hg, As removal rate >95%). The SO2 concentration in the flue gas is detected at the gas outlet of activated carbon adsorption tower 13 and meets the standard (SO2 ≤ 35 mg / m³). 3 The clean gas is then discharged. Activated carbon adsorption tower 13 is regenerated by hot nitrogen purging. Saturated activated carbon can be regenerated by water washing or heating. The nitrogen temperature is controlled at 180℃±10℃, and the flow rate is 500-800 m³ / h. 3 / h; purge time 4-6 hours, adsorption capacity recovery ≥95% after regeneration.

[0041] S4. Waste liquid recovery: The NaOH waste liquid containing Na2SO3, after desulfurization in the E-RPB reaction unit, flows from the discharge port 10 to the neutralization tank 16. Lime slurry from the lime slurry tank 15 is added to the NaOH waste liquid containing Na2SO3 in the neutralization tank 16 to carry out a neutralization reaction. This neutralization reaction uses a wet flue gas desulfurization process with lime slurry precipitation and regeneration. The formula is as follows: , After neutralization, 40% NaOH clear liquid is collected and reused in adsorbent storage tank 12. The recovered 40% NaOH clear liquid is recycled for the desulfurization process, reducing NaOH consumption.

[0042] Online cleaning of S5 and E-RPB reaction units: Every 72 hours of system operation, the E-RPB reaction unit will undergo an online cleaning procedure: gas inlet 5 is closed, rotor 8 is maintained at a speed of 200 r / min; a 2% citric acid solution is sprayed into the E-RPB reaction unit through the atomizing nozzle of the annular liquid inlet pipe 9 to rinse the rotating three-layer interlaced mesh packing layer 7 for 30 minutes, i.e., citric acid absorption. Citric acid (H3C6H5O7·H2O) solution has good buffering performance. When residual SO2 inside the E-RPB reaction unit passes through the citric acid solution, SO2 can be continuously and efficiently absorbed, with an SO2 absorption rate of over 99%; the waste liquid after cleaning is discharged through drain port 10. S6. Repeat S1-S5 to purify the flue gas again.

[0043] like Figures 2 to 4 As shown, the experimental analysis is as follows: 1. Verification of desulfurization efficiency: The synergistic effect of the rotating three-layer staggered mesh packing layer 7; After pretreatment, the flue gas to be treated enters the rotating three-layer staggered grid packing layer 7 of the E-RPB reaction unit in the same direction as the NaOH solution; Upper packing layer (initial high-efficiency contact zone): SO2 reacts rapidly with NaOH, achieving an initial desulfurization rate of 40±5%; Middle packing layer (turbulent enhanced mass transfer zone): Rotation generates micro-vortices, increasing the mass transfer coefficient to 1.25 s⁻¹. -1 The desulfurization rate increased to 85±3% (droplet Reynolds number Re>5000); Lower packing layer (reaction completion zone): The area where the reaction is finally completed. At the same time, centrifugal force throws the waste liquid after the reaction to the chamber wall, with a liquid holding capacity of <5%, ensuring the continuity of the reaction. Overall desulfurization rate: at an inlet SO2 concentration of 2870±120 mg / m³ 3 Under operating conditions, the outlet concentration decreased to 28.5±3.2 mg / m³. 3 The average desulfurization rate is 98.0±0.5%, breaking through the 90% bottleneck of traditional technology.

[0044] 2. Mass transfer and energy consumption performance: Centrifugal force field enhancement mechanism to achieve precise matching between rotational speed and flue gas flow rate: Energy efficiency advantage: The optimized packing structure (porosity 0.92) reduces the system pressure drop to 140 Pa, saving 35% energy compared to the traditional spray tower (3200 Pa).

[0045] 3. Validation of anti-clogging and long-term operation: The external cavity features a 6-inlet liquid design to prevent sulfur deposition in the packing layer. Combined with online cleaning every 72 hours (2% citric acid solution, 200 r / min rinsing for 30 minutes), after 8000 hours of continuous operation, the packing pressure difference increases by ≤3% (compared to 15% for traditional packed towers after 2000 hours); the desulfurization rate fluctuates by <0.8%. Waste liquid recycling economy: NaOH waste liquid (containing Na2SO3) is neutralized with lime milk, and 40% of the clear liquid is recycled to adsorbent storage tank 12, reducing NaOH consumption by 32%.

[0046] 4. Environmental emission compliance: Deep removal of heavy metals: After treatment by an activated carbon tower, the residual concentrations of Hg and As in the purified gas are ≤0.05 mg / m³. 3 The removal rate is >95%, which meets the requirements of the "Integrated Emission Standard for Air Pollutants" (GB 16297-1996).

[0047] Exhaust gas co-control: Baffle demister 14 (pressure drop ≤200 Pa) captures droplets with a diameter >5 μm, and the outlet mist carryover is <10 mg / m³. 3 .

[0048] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A centrifugal purification system for treating flue gas, characterized in that: It includes a flue gas storage tank (1), a pretreatment unit, an E-RPB reaction unit, a post-treatment unit, a recovery unit, and a cleaning unit; the flue gas storage tank (1) is connected to the pretreatment unit to remove dust, exchange heat, and regulate humidity of the flue gas; the pretreatment unit is connected to the E-RPB reaction unit to desulfurize the flue gas; the E-RPB reaction unit is connected to the post-treatment unit, the recovery unit, and the cleaning unit respectively to discharge the clean flue gas after desulfurization, to recycle and reuse the waste liquid generated after flue gas desulfurization, and to clean the E-RPB reaction unit; The pretreatment unit includes an electrostatic precipitator (2), a heat exchanger (3), and a humidity regulator (4). The E-RPB reaction unit includes an outer cavity (6), an exhaust port (11) and a liquid outlet (10) located on the left side of the outer cavity (6), a gas inlet (5) located on the top of the outer cavity (6), an annular liquid inlet pipe (9) located on the side of the outer cavity (6), an adsorbent storage tank (12) connected to the annular liquid inlet pipe (9), a grid packing layer (7) located inside the outer cavity (6), and a rotor (8) installed at the center of the grid packing layer (7). The post-treatment unit includes a baffle demister (14) connected to the exhaust port (11) and an activated carbon adsorption tower (13) connected to the baffle demister (14). The recycling unit includes a neutralization tank (16) connected to the drain port (10) and a lime slurry tank (15) connected to the neutralization tank (16). The cleaning unit includes a citric acid solution storage tank (18) connected to the E-RPB reaction unit. The rotating three-layer staggered mesh packing layer (7) includes an upper packing layer, a middle packing layer and a lower packing layer; the upper packing layer is the initial high-efficiency dissolution zone; the middle packing layer is the turbulent enhanced mass transfer zone; and the lower packing layer is the reaction completion zone.

2. The centrifugal purification system for treating flue gas according to claim 1, characterized in that: The electrostatic precipitator (2) connected to the flue gas storage tank (1) has an electrode spacing of 200 mm, an operating voltage of 50-80 kV, removes particles >10 μm from the flue gas, and has an outlet dust content ≤30 mg / m³. 3 The heat exchanger (3) is connected to the electrostatic precipitator (2), and the heat exchanger (3) is a shell-and-tube heat exchanger with a heat exchange area of ​​60 m². 2 The cooling medium is circulating water, which cools the flue gas from 140-180℃ to 50-70℃; the humidity regulator (4) is connected to the heat exchanger (3), and the humidity regulator (4) is a steam jet humidity regulator (4) with a steam pressure of 0.3-0.5MPa, which adjusts the humidity of the flue gas to 60%-80%.

3. The centrifugal purification system for treating flue gas according to claim 1, characterized in that: The outer cavity (6) is a cylindrical outer cavity (6) with a diameter of 1000mm, a height of 810mm, and is made of 316L stainless steel with a pressure resistance of 0.4MPa; the annular liquid inlet pipe (9) is evenly distributed with several atomizing nozzles, with 6-8 atomizing nozzles, each atomizing nozzle having a swirl core structure, an inlet pressure of 0.4-0.6MPa, a flow fluctuation of ≤±5%, an atomized particle size of 80-150μm, and a built-in self-cleaning needle valve for the atomizing nozzle, with a backwashing cycle of 24 hours; the mesh filler layer (7) has a mesh wire diameter of 0.35mm±0.05mm, a layer spacing of 20mm±2mm, and a short-flow prevention baffle ring with a height of 10mm and a thickness of 2mm between adjacent mesh layers; the mesh material of the upper filler layer is 304 stainless steel; the mesh material of the middle filler layer is 316 stainless steel; and the mesh material of the lower filler layer is 304 stainless steel.

4. The centrifugal purification system for treating flue gas according to claim 1, characterized in that: The rotor (8) is coaxial with the center of the outer cavity (6). The rotor (8) has a power of 15kW and a speed of 300-900r / min. The rotor (8) is driven to rotate by a frequency conversion drive system (20) and a bearing temperature detection system (21) to detect the rotor shaft temperature. The frequency conversion drive system (20) has a speed adjustment response time of ≤3 seconds, and the bearing temperature detection system (21) is set to an over-temperature threshold of 80℃.

5. The centrifugal purification system for treating flue gas according to claim 1, characterized in that: It also includes an ultrasonic level sensor (19) connected to the outer cavity (6) for monitoring the amount of waste liquid deposited at the bottom of the cavity after desulfurization by the E-RPB reaction unit.

6. The centrifugal purification system for treating flue gas according to claim 1, characterized in that: The baffle plate demister (14) has a plate spacing of 22 mm to remove entrained droplets; the activated carbon adsorption tower (13) has a filling amount of 250 kg.

7. The centrifugal purification system for treating flue gas according to claim 1, characterized in that: The neutralization tank (16) is equipped with an online pH probe (22) with a range of 0-14 and an accuracy of ±0.

1. The neutralization tank (16) uses the clear liquid neutralized by lime milk after desulfurization of the E-RPB reaction unit to return the clear liquid to the adsorbent storage tank (12) through the clear liquid recycling pipeline (17), with a recycling rate of 40%.

8. A flue gas purification method for a centrifugal purification system for treating flue gas according to any one of claims 1 to 7, characterized in that: Includes the following steps: S1. Flue gas pretreatment: The flue gas to be treated is injected into the flue gas storage tank (1), and after electrostatic dust removal by the electrostatic precipitator (2), the dust content inside the gas is reduced to 30 mg / m³. 3 Next, the gas temperature is reduced to 60±5℃ by passing through a shell-and-tube heat exchanger (3) to prevent droplet evaporation caused by high temperature; the flue gas humidity is adjusted to RH70±5% by passing through a steam jet humidity regulator (4). S2, Centrifugal force field enhanced desulfurization: The pretreated flue gas enters the E-RPB reaction unit from the gas inlet (5) at a tangential velocity of 6.0±0.5m / s; 15%-20% NaOH solution is sprayed into the rotating three-layer interlaced grid packing layer (7) at a velocity of 2.0±0.2m / s through the atomizing nozzle of the annular liquid inlet pipe (9); desulfurization is carried out through the E-RPB reaction unit; S3. Gas-liquid purification and separation: After desulfurization in the E-RPB reaction unit, the gas from centrifugal force-enhanced desulfurization passes through the exhaust port (11) and a baffle plate demister (14) to remove droplets. The gas then enters the activated carbon adsorption tower (13) to remove residual heavy metals. The removal rates of Hg and As are >95%. The SO2 concentration in the flue gas is detected at the gas outlet of the activated carbon adsorption tower (13), and the standard SO2 ≤ 35 mg / m³ is met. 3 The clean gas is then discharged. S4. Waste liquid recovery: The NaOH waste liquid containing Na2SO3, which has been desulfurized by the E-RPB reaction unit, flows from the discharge port (10) to the neutralization tank (16). Lime slurry from the lime slurry tank (15) is added to the NaOH waste liquid containing Na2SO3 in the neutralization tank (16) to carry out a neutralization reaction. This neutralization reaction uses a wet flue gas desulfurization process with lime slurry precipitation and regeneration. The formula is: ， After neutralization, 40% NaOH clear liquid is collected and reused in the adsorbent storage tank (12). The recovered 40% NaOH clear liquid is recycled for the desulfurization process, reducing NaOH consumption. Online cleaning of S5 and E-RPB reaction units: Every 72 hours of operation, the E-RPB reaction unit will undergo an online cleaning procedure: the gas inlet (5) will be closed, and the rotor (8) speed will be maintained at 200 r / min; 2% citric acid solution will be sprayed into the E-RPB reaction unit through the atomizing nozzle of the annular liquid inlet pipe (9) to rinse the rotating three-layer interlaced grid packing layer (7) for 30 minutes, i.e., the citric acid absorption method; the waste liquid after cleaning will be discharged through the drain port (10); S6. Repeat S1-S5 to purify the flue gas.

9. The flue gas purification method of the centrifugal purification system for treating flue gas according to claim 8, characterized in that: In S3, the activated carbon adsorption tower (13) is regenerated by hot nitrogen purging. The saturated activated carbon can be regenerated by water washing or heating. The nitrogen temperature is controlled at 180℃±10℃ and the flow rate is 500-800 m³ / h. 3 / h; purge time 4-6 hours, adsorption capacity recovery ≥95% after regeneration.

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