Method for staged purification of furnace sealing flue gas of pre-pumping pump and collaborative removal of pollutants

Abstract

The invention discloses a method for staged purification of furnace sealing flue gas of a pre-pumping pump and collaborative removal of pollutants, relates to the field of metallurgical industry, and aims to solve the problems of poor adaptation of fixed parameters, complex multi-pollutant treatment system and high energy consumption cost in the prior art. Detecting parameters in real time and regulating and controlling the injection amount and turbulent flow velocity of the modified quicklime powder to finish pretreatment; then entering a primary purification tower, dynamically optimizing the spraying liquid-gas ratio and the electrostatic voltage, and removing SO2 and dust in a targeted manner; then, through a secondary reaction tower, the ozone generation amount and the modified activated carbon injection amount are accurately controlled, and NOx and VOCs are synergistically and deeply removed; and finally, detecting the pollutant concentration through a tail end refining device, and realizing closed-loop emission in combination with standard judgment and a reflux mechanism. Dynamic matching of process parameters and flue gas working conditions is achieved, multiple sets of independent equipment are not needed, it is guaranteed that emission stably reaches the standard, and economical efficiency and practicability are outstanding.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metallurgical industry, in particular to a method for staged purification and simultaneous removal of pollutants of furnace sealing flue gas by pre-pumping. BACKGROUND

[0002] In the fields of metallurgy, chemical industry, etc., pre-pumping furnace sealing is a key process link to ensure equipment maintenance and maintain production continuity. However, during the operation process, it will continuously produce composite flue gas containing dust, sulfur dioxide and nitrogen oxides, and under some working conditions, it will also be accompanied by volatile organic emissions. Such flue gas needs to be deeply purified to meet the standards before being discharged, otherwise it will exacerbate air pollution and trigger environmental penalties. Therefore, the reliability and economy of flue gas purification technology have become the core concern of enterprise production and operation.

[0003] The current mainstream pre-pumping furnace sealing flue gas purification technology in the industry has obvious shortcomings. First of all, it is poor in working condition adaptability. The existing technology generally uses fixed process parameters for design, such as fixing the liquid-gas ratio of ammonia water-urea spray liquid in the desulfurization link, fixing the electrostatic capture voltage in the dust removal link, and fixing the active carbon injection amount in the adsorption link. However, the pollutant concentration of pre-pumping furnace sealing flue gas is greatly affected by the pressure in the furnace, the material combustion state and the sealing time, and the fixed parameters cannot match this fluctuation characteristic. When the pollutant concentration is high, it is easy to cause incomplete removal and lead to emission exceeding the standard; when the concentration is low, it will cause excessive consumption of reagents, adsorbents and other consumables, forming a double dilemma of "difficult to meet the standard" and "high cost".

[0004] Secondly, the existing technology has weak multi-pollutant simultaneous treatment capability. In order to remove multiple pollutants in the flue gas, the industry often uses the "device in series" mode, that is, to remove dust by independent bag-type dust collector, to remove SO2 by independent desulfurization tower, and to remove denitration by independent selective catalytic reduction device. In some scenes, a VOCs adsorption tower needs to be additionally added. This decentralized system not only has complex structure and large floor area, but also has the defect of coordination, thereby increasing the equipment maintenance frequency and initial investment cost, which is difficult for small and medium-sized enterprises to bear.

[0005] In addition, the existing technology is inefficient in energy consumption and consumable control. Due to the lack of dynamic control mechanism, the spray system often causes energy consumption redundancy of circulating pump due to too high liquid-gas ratio, and the electrostatic capture module still runs at high voltage when the dust concentration is low, causing invalid energy consumption. At the same time, the impact flow state of the flue gas entering the purification device is not optimized, which easily leads to a pressure loss of more than 800 Pa in the equipment, further increasing the load of the induced draft fan.

[0006] In summary, current pre-extraction pump-sealed flue gas purification technology faces prominent problems such as poor adaptability to operating conditions, weak multi-pollutant synergistic treatment capability, and high energy and material costs. There is an urgent need for a technical solution that can achieve dynamic parameter control, integrated removal of multiple pollutants, and excellent economic efficiency to meet the environmental protection requirements and cost control objectives of industrial production. Summary of the Invention

[0007] The purpose of this invention is to provide a method for graded purification and synergistic removal of pollutants from pre-pumped and sealed flue gas. By real-time monitoring of parameters such as concentration, temperature, and flow rate of flue gas at each stage, the method dynamically calculates and controls key operating parameters such as the amount of modified quicklime powder injected, the optimal liquid-to-gas ratio of the spray liquid, the amount of ozone generated, and the amount of modified activated carbon injected. Through a multi-stage process, the method achieves synergistic and efficient removal of multiple pollutants while ensuring stable and compliant emissions of flue gas.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas, characterized by comprising the following steps:

[0010] S1: The flue gas discharged from the pre-extraction pump and the sealed furnace is introduced into the dynamic conditioning device. The flue gas inlet parameters are detected in real time, and then the dynamic injection amount of modified quicklime powder and the optimal speed of the spiral turbulence component are calculated to pre-treat the flue gas.

[0011] S2: The pretreated flue gas is introduced into the primary purification tower, and the residual SO2 concentration and dust concentration in the flue gas are detected in real time. The optimal liquid-gas ratio of the ammonia-urea mixed spray liquid and the set voltage of the electrostatic capture module are calculated by formula to remove SO2 and dust in a targeted manner.

[0012] S3: Introduce the purified flue gas from the primary stage into the secondary reaction tower, and monitor NO in real time. x Based on the concentrations of nitrogen oxides (NOx) and VOCs, calculate the ozone generation and the injection rate of modified activated carbon, and perform NO testing. x Catalytic synergistic deep removal of VOCs;

[0013] S4: The flue gas after secondary purification is introduced into the terminal refining unit, where residual pollutants are removed by a honeycomb molecular sieve adsorption tower. The outlet pollutant concentration is monitored in real time, and the compliance judgment index and reflux trigger threshold are calculated to determine whether to directly discharge the flue gas or return it to the primary purification tower for reprocessing, thus forming a closed-loop control.

[0014] Step S1 specifically involves introducing the flue gas discharged from the pre-extraction pump into the dynamic conditioning device and monitoring the flue gas inlet parameters in real time, including dust concentration. Initial SO2 concentration ,temperature Flow rate The amount of modified quicklime powder injected was calculated using the dynamic injection rate calculation formula. The specific formula is as follows:

[0015] ;

[0016] In the formula, The adsorption coefficient is denoted as 0.8-1.2. The cross-sectional area of ​​the device is... The target efficiency for SO2 removal in the pretreatment stage is set at 45%. The bulk density of modified quicklime powder, This is a temperature correction factor. This is the optimal adsorption temperature.

[0017] Step S1 also includes determining the optimal rotational speed of the helical turbulence assembly. The calculation formula is as follows:

[0018] ;

[0019] In the formula, The velocity coupling coefficient is... The dust concentration threshold, Based on the base rotation speed and calculation results, large dust particles with a diameter ≥50μm are first removed by an inertial settling component. Then, the temperature is adjusted, and modified quicklime powder is injected at a injection rate Q. The rotation speed is then adjusted accordingly. The spiral turbulence component enables efficient gas-solid mixing and initial adsorption of SO2.

[0020] In step S2, the optimal liquid-to-gas ratio of the ammonia-urea mixed spray solution is calculated. The formula is as follows:

[0021] ;

[0022] In the formula, This is the SO2 concentration weighting coefficient, with a value ranging from 0.02 to 0.05. This is the dust concentration weighting coefficient, with a value ranging from 0.01 to 0.03. The overall efficiency of primary removal. The initial pH value of the spray solution is given. Based on the calculation results, the liquid-to-gas ratio of the spray solution is controlled at L / G.

[0023] The set voltage of the electrostatic capture module in step S2 The calculation formula is as follows:

[0024] ;

[0025] In the formula, This is the maximum voltage for electrostatic capture. This is the dust conductivity correction factor. Based on the calculated dust concentration, a voltage is applied to the electrostatic precipitator module inside the primary purification tower. Electrostatic collection is used to remove most of the SO2 and residual dust.

[0026] Ozone generation in step S3 The calculation formula is as follows:

[0027] ;

[0028] In the formula, NO x The oxidation coefficient ranges from 0.8 to 1.2. The instantaneous volumetric flow rate of the flue gas. NO x The target efficiency is set at 95%. The VOCs synergistic oxidation coefficient is set at 0.002-0.005. Based on the calculation results, the ultraviolet photocatalytic module is activated to generate ozone, with an ozone generation amount of [missing value]. .

[0029] Step S3: Injection amount of modified activated carbon The calculation formula is as follows:

[0030] ;

[0031] In the formula, The adsorption coefficient ranges from 0.001 to 0.003. NO x The adsorption weight is 1.2-1.5, and β is the VOCs adsorption weight, with a value of 0.8-1.0. This refers to the flue gas residence time, with a value of 12-15 seconds. The porosity of activated carbon is 0.7-0.8. This represents the specific surface area of ​​activated carbon; based on the calculation results, it is calculated according to the injection rate. Spray-modified activated carbon.

[0032] Step S4: Real-time monitoring of outlet pollutant concentration Calculate the compliance index With reflux trigger threshold The formula is as follows:

[0033] ;

[0034] ;

[0035] In the formula, where: These are the weighting coefficients for each pollutant, and their sum is 1. The national standard limit is, This is a pressure loss correction factor, with a value ranging from 0.1 to 0.2. For real-time pressure loss of the system, For the maximum permissible pressure loss; when At that time, the flue gas is directly discharged through the induced draft fan; when When the flue gas is returned to the primary purification tower for reprocessing, the return valve is automatically triggered, forming a closed-loop control.

[0036] The modified quicklime powder is prepared by mixing quicklime powder with a magnesium sulfate solution of 5%-8% by mass at a solid-liquid ratio of 1:3, drying, and then calcining at 300-350℃ for 2 hours.

[0037] In step S3, a conical ash collection hopper is installed at the bottom of the secondary reaction tower, with the hopper wall inclined at an angle of not less than 60°. This hopper is used to collect unreacted modified activated carbon particles. After being screened to remove impurities, the particles can be returned to the secondary reaction tower for re-spraying, thus reducing material consumption.

[0038] First, in the dynamic conditioning pretreatment stage of flue gas, the dust concentration ρ0, initial SO2 concentration C0, temperature T0, and flow rate v0 of the flue gas from the pre-pumped furnace are monitored in real time. A customized formula is used to dynamically calculate the injection rate Q of modified quicklime powder and the optimal rotation speed n of the spiral turbulence assembly. This ensures a precise match between the quicklime powder dosage and SO2 adsorption requirements. The rotation speed n is dynamically adjusted based on the flue gas velocity and dust concentration. The spiral turbulence enhances gas-solid mixing, and the inertial settling assembly efficiently removes large dust particles with a diameter ≥50μm. Simultaneously, the adsorption activity of the modified quicklime powder initially captures 30%-40% of the SO2, laying the foundation for subsequent deep purification.

[0039] Entering the first-stage targeted removal phase, the residual SO2 concentration C1 and dust concentration ρ1 in the pretreated flue gas are monitored in real time. By using the liquid-to-gas ratio formula, the pollutant concentration, removal efficiency, and pH value of the spray solution are correlated to determine the optimal liquid-to-gas ratio L / G of the ammonia-urea mixed spray solution. Multi-layer spraying and porous sieve plates are used to extend the gas-liquid contact time and enhance the SO2 absorption reaction. At the same time, the electrostatic capture voltage formula is used to dynamically adjust the set voltage U according to the dust concentration. The electric field force generated by the high voltage is used to capture fine dust and atomized droplets, achieving synergistic and efficient removal of SO2 and dust, avoiding the problem of incomplete removal of mixed pollutants by a single process.

[0040] In the secondary catalytic synergistic deep removal stage, the NO residue after primary purification is targeted... x And VOCs, their concentration is monitored in real time, and NO is coupled through the ozone generation formula. xBy combining removal efficiency with VOCs synergistic oxidizing factors, the ozone production of the ultraviolet photocatalytic module is precisely controlled. The strong oxidizing properties of ozone are used to oxidize the difficult-to-remove NO into easily adsorbed NO2. Simultaneously, by using a modified activated carbon injection rate formula, combined with the adsorption weights of the two pollutants and the characteristic parameters of the activated carbon, the optimal injection rate is determined. Through the catalytic-adsorption synergistic effect of MnO2-loaded activated carbon, ozone and NO are catalyzed on one hand... x On the one hand, it undergoes oxidation reaction, and on the other hand, it efficiently adsorbs VOCs and reaction products to achieve NO. x It achieves a deep purification effect with a removal rate of ≥95% and a VOCs removal rate of ≥85%.

[0041] Finally, in the end-of-pipe purification and closed-loop control stage, the highly selective adsorption performance of honeycomb molecular sieves is used to remove residual trace pollutants, and the outlet SO2 and NO are obtained in real time through online monitoring. x VOCs and dust concentrations are substituted into the compliance judgment index formula, and the purification effect is quantified by combining the proportion and weight coefficient of each pollutant relative to the national standard limit; at the same time, the backflow trigger threshold is calculated by combining the real-time pressure loss of the system. When flue gas is directly emitted, The system automatically triggers a reflux mechanism to return substandard flue gas to the primary purification tower for reprocessing, forming a closed-loop system that addresses the pain points of traditional processes, such as inadequate one-time treatment and poor emission stability.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] 1. Existing technologies mostly use fixed process parameters, which cannot match the large fluctuations in flue gas conditions caused by pre-extraction pump sealing, resulting in dust, SO2, and NO. x The dynamic change in concentration with furnace conditions can easily lead to problems such as "incomplete removal at high concentrations and waste of consumables at low concentrations". This invention uses real-time detection of flue gas inlet / outlet parameters and customized formulas to dynamically calculate key operating parameters such as the amount of modified quicklime powder injected, the speed of the spiral turbulence, and the amount of ozone generated, so that the process parameters are precisely matched with the flue gas conditions.

[0044] 2. Existing technologies are often designed for single pollutants, requiring multiple independent devices to be connected in series to treat multiple pollutants, resulting in complex systems, poor coordination, and large footprint. This invention achieves simultaneous removal of multiple pollutants in one system through a graded process, combining ammonia-urea spraying with electrostatic capture and a synergistic mechanism of ozone oxidation and modified activated carbon adsorption, without the need for additional independent equipment.

[0045] 3. By dynamically adjusting the spray liquid-gas ratio and electrostatic collection voltage using a formula, excessive consumption of consumables can be avoided. At the same time, by reducing system pressure loss through an anti-impact guide plate and dynamically adjusting energy output in conjunction with flue gas flow, the overall operating energy consumption is reduced by 15%-20% compared to existing technologies, significantly reducing industrial application costs. Attached Figure Description

[0046] Figure 1 This is a flowchart of a pre-extraction pump sealing flue gas staged purification and pollutant synergistic removal method according to the present invention. Detailed Implementation

[0047] The technical solutions of the present invention will now be described in detail with reference to the accompanying drawings.

[0048] like Figure 1 As shown, a method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas is characterized by the following steps:

[0049] S1: The flue gas discharged from the pre-extraction pump and the sealed furnace is introduced into the dynamic conditioning device. The flue gas inlet parameters are detected in real time, and then the dynamic injection amount of modified quicklime powder and the optimal speed of the spiral turbulence component are calculated to pre-treat the flue gas.

[0050] S2: The pretreated flue gas is introduced into the primary purification tower, and the residual SO2 concentration and dust concentration in the flue gas are detected in real time. The optimal liquid-gas ratio of the ammonia-urea mixed spray liquid and the set voltage of the electrostatic capture module are calculated by formula to remove SO2 and dust in a targeted manner.

[0051] S3: Introduce the purified flue gas from the primary stage into the secondary reaction tower, and monitor NO in real time. x Based on the concentrations of nitrogen oxides (NOx) and VOCs, calculate the ozone generation and the injection rate of modified activated carbon, and perform NO testing. x Catalytic synergistic deep removal of VOCs;

[0052] S4: The flue gas after secondary purification is introduced into the terminal refining unit, where residual pollutants are removed by a honeycomb molecular sieve adsorption tower. The outlet pollutant concentration is monitored in real time, and the compliance judgment index and reflux trigger threshold are calculated to determine whether to directly discharge the flue gas or return it to the primary purification tower for reprocessing, thus forming a closed-loop control.

[0053] Step S1 specifically involves introducing the flue gas discharged from the pre-extraction pump into the dynamic conditioning device and monitoring the flue gas inlet parameters in real time, including dust concentration. Initial SO2 concentration ,temperature Flow rate The amount of modified quicklime powder injected was calculated using the dynamic injection rate calculation formula. The specific formula is as follows:

[0054] ;

[0055] In the formula, The adsorption coefficient is denoted as 0.8-1.2. The cross-sectional area of ​​the device is... The target efficiency for SO2 removal in the pretreatment stage is set at 45%. The bulk density of modified quicklime powder, This is a temperature correction factor. This is the optimal adsorption temperature.

[0056] Step S1 also includes determining the optimal rotational speed of the helical turbulence assembly. The calculation formula is as follows:

[0057] ;

[0058] In the formula, The velocity coupling coefficient is... The dust concentration threshold, Based on the base rotation speed and calculation results, large dust particles with a diameter ≥50μm are first removed by an inertial settling component. Then, the temperature is adjusted, and modified quicklime powder is injected at a injection rate Q. The rotation speed is then adjusted accordingly. The spiral turbulence component enables efficient gas-solid mixing and initial adsorption of SO2.

[0059] In step S2, the optimal liquid-to-gas ratio of the ammonia-urea mixed spray solution is calculated. The formula is as follows:

[0060] ;

[0061] In the formula, This is the SO2 concentration weighting coefficient, with a value ranging from 0.02 to 0.05. This is the dust concentration weighting coefficient, with a value ranging from 0.01 to 0.03. The overall efficiency of primary removal. The initial pH value of the spray solution is given. Based on the calculation results, the liquid-to-gas ratio of the spray solution is controlled at L / G.

[0062] The set voltage of the electrostatic capture module in step S2 The calculation formula is as follows:

[0063] ;

[0064] In the formula, This is the maximum voltage for electrostatic capture. This is the dust conductivity correction factor. Based on the calculated dust concentration, a voltage is applied to the electrostatic precipitator module inside the primary purification tower. Electrostatic collection is used to remove most of the SO2 and residual dust.

[0065] Ozone generation in step S3 The calculation formula is as follows:

[0066] ;

[0067] In the formula, NO x The oxidation coefficient ranges from 0.8 to 1.2. The instantaneous volumetric flow rate of the flue gas. NO x The target efficiency is set at 95%. The VOCs synergistic oxidation coefficient is set at 0.002-0.005. Based on the calculation results, the ultraviolet photocatalytic module is activated to generate ozone, with an ozone generation amount of [missing value]. .

[0068] Step S3: Injection amount of modified activated carbon The calculation formula is as follows:

[0069] ;

[0070] In the formula, The adsorption coefficient ranges from 0.001 to 0.003. NO x The adsorption weight is 1.2-1.5, and β is the VOCs adsorption weight, with a value of 0.8-1.0. This refers to the flue gas residence time, with a value of 12-15 seconds. The porosity of activated carbon is 0.7-0.8. This represents the specific surface area of ​​activated carbon; based on the calculation results, it is calculated according to the injection rate. Spray-modified activated carbon.

[0071] Step S4: Real-time monitoring of outlet pollutant concentration Calculate the compliance index With reflux trigger threshold The formula is as follows:

[0072] ;

[0073] ;

[0074] In the formula, where: These are the weighting coefficients for each pollutant, and their sum is 1. The national standard limit is, This is a pressure loss correction factor, with a value ranging from 0.1 to 0.2. For real-time pressure loss of the system, For the maximum permissible pressure loss; when At that time, the flue gas is directly discharged through the induced draft fan; when When the flue gas is returned to the primary purification tower for reprocessing, the return valve is automatically triggered, forming a closed-loop control.

[0075] The modified quicklime powder is prepared by mixing quicklime powder with a magnesium sulfate solution of 5%-8% by mass at a solid-liquid ratio of 1:3, drying, and then calcining at 300-350℃ for 2 hours.

[0076] In step S3, a conical ash collection hopper is installed at the bottom of the secondary reaction tower, with the hopper wall inclined at an angle of not less than 60°. This hopper is used to collect unreacted modified activated carbon particles. After being screened to remove impurities, the particles can be returned to the secondary reaction tower for re-spraying, thus reducing material consumption.

[0077] Taking the pre-extraction pump-assisted flue gas treatment system for a 3000m³ blast furnace as an example, this system needs to handle 15000m³ / h of flue gas for blast furnace sealing daily. The specific implementation process is as follows: After the system is turned on, the flue gas discharged from the pre-extraction pump is first introduced into the dynamic conditioning device. The dust concentration at the flue gas inlet is 25g / m³, the initial SO2 concentration is 1800mg / m³, the temperature is 95℃, and the flow rate is 12m / s. The dynamic injection rate of modified quicklime powder is calculated to be 8.2kg / h, and the optimal rotation speed of the spiral turbulence component is 75r / min. Then, large particles of dust with a particle size ≥50μm are removed by the inertial settling component in the device. The flue gas temperature is then stabilized to 98℃, and modified quicklime powder is injected according to the calculated amount. After being mixed by the spiral turbulence component, the flue gas is further treated. After initial adsorption, 38% of SO2 was adsorbed. The pretreated flue gas was then introduced into the primary purification tower. The residual SO2 concentration at the tower inlet was measured at 1116 mg / m³, and the dust concentration at 1.0 g / m³. Calculations determined the optimal liquid-to-gas ratio for the ammonia-to-urea mixture (3:1 mass ratio) to be 10 L / m³. The electrostatic precipitator was set to 38 kV. The spray system was controlled to spray at this liquid-to-gas ratio while applying 38 kV. The gas-liquid contact time was extended using three layers of 6 mm porous sieves within the tower, ultimately removing 92% of the remaining SO2 and 95% of the remaining dust. At this point, the SO2 concentration in the flue gas decreased to 89 mg / m³, and the dust concentration decreased to 50 mg / m³. The purified flue gas was then introduced into the secondary reaction tower, where NO was detected. x With a concentration of 420 mg / m³ and VOCs concentration of 85 mg / m³, the calculated ozone generation rate was 120 m³ / h, and the modified activated carbon injection rate was 1.5 kg / h. An ultraviolet photocatalytic module with a wavelength of 310 nm and a power of 65 W was activated to generate ozone. Modified activated carbon was injected according to the calculated rate, and the residence time of the flue gas in the tower was controlled to 13 seconds. 96% of NO was removed through catalytic oxidation-adsorption synergistic effect.x With 88% VOCs, the NO in the flue gas at this time x The concentration of SO2 was reduced to 17 mg / m³ and the concentration of VOCs was reduced to 10.2 mg / m³. Finally, the flue gas after secondary purification was introduced into the terminal refining unit. After adsorption by the honeycomb molecular sieve adsorption tower, the SO2 concentration of the outlet flue gas was monitored in real time to be 4.2 mg / m³ and NO2 concentration to be 10.2 mg / m³. x With a concentration of 3.8 mg / m³, VOCs concentration of 3.5 mg / m³, and dust concentration of 3.1 mg / m³, the calculated compliance judgment index is 0.62 and the reflux trigger threshold is 0.95. Since the compliance judgment index is less than the reflux threshold, the flue gas is directly discharged through the induced draft fan. At the same time, the unreacted modified activated carbon collected in the conical ash collection hopper at the bottom of the secondary reaction tower is recovered at a rate of 75% after screening and impurity removal, and can be returned to the tower for reuse. The energy consumption of the entire system is reduced by 18% compared with the traditional process.

Claims

1. A method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas, characterized in that, Includes the following steps: S1: The flue gas discharged from the pre-extraction pump and the sealed furnace is introduced into the dynamic conditioning device. The flue gas inlet parameters are detected in real time, and then the dynamic injection amount of modified quicklime powder and the optimal speed of the spiral turbulence component are calculated to pre-treat the flue gas. S2: The pretreated flue gas is introduced into the primary purification tower, and the residual SO2 concentration and dust concentration in the flue gas are detected in real time. The optimal liquid-gas ratio of the ammonia-urea mixed spray liquid and the set voltage of the electrostatic capture module are calculated by formula to remove SO2 and dust in a targeted manner. S3: Introduce the purified flue gas from the primary stage into the secondary reaction tower, and monitor NO in real time. x Based on the concentrations of nitrogen oxides (NOx) and VOCs, calculate the ozone generation and the injection rate of modified activated carbon, and perform NO testing. x Catalytic synergistic deep removal of VOCs; S4: The flue gas after secondary purification is introduced into the terminal refining unit, where residual pollutants are removed by a honeycomb molecular sieve adsorption tower. The outlet pollutant concentration is monitored in real time, and the compliance judgment index and reflux trigger threshold are calculated to determine whether to directly discharge the flue gas or return it to the primary purification tower for reprocessing, thus forming a closed-loop control.

2. The method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas according to claim 1, characterized in that, Step S1 specifically involves introducing the flue gas discharged from the pre-extraction pump into the dynamic conditioning device and monitoring the flue gas inlet parameters in real time, including dust concentration. Initial SO2 concentration ,temperature Flow rate The amount of modified quicklime powder injected was calculated using the dynamic injection rate calculation formula. The specific formula is as follows: ； In the formula, The adsorption coefficient is denoted as 0.8-1.

2. The cross-sectional area of ​​the device is... The target efficiency for SO2 removal in the pretreatment stage is set at 45%. The bulk density of modified quicklime powder, This is a temperature correction factor. This is the optimal adsorption temperature.

3. The method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas according to claim 2, characterized in that, Step S1 also includes determining the optimal rotational speed of the helical turbulence assembly. The calculation formula is as follows: ； In the formula, The velocity coupling coefficient is... The dust concentration threshold, Based on the base rotation speed and calculation results, large dust particles with a diameter ≥50μm are first removed by an inertial settling component. Then, the temperature is adjusted, and modified quicklime powder is injected at a injection rate Q. The rotation speed is then adjusted accordingly. The spiral turbulence component enables efficient gas-solid mixing and initial adsorption of SO2.

4. The method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas according to claim 1, characterized in that, In step S2, the optimal liquid-to-gas ratio of the ammonia-urea mixed spray solution is calculated. The formula is as follows: ； In the formula, This is the SO2 concentration weighting coefficient, with a value ranging from 0.02 to 0.

05. This is the dust concentration weighting coefficient, with a value ranging from 0.01 to 0.

03. The overall efficiency of primary removal. The initial pH value of the spray solution is given. Based on the calculation results, the liquid-to-gas ratio of the spray solution is controlled at L / G.

5. The method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas according to claim 1, characterized in that, The set voltage of the electrostatic capture module in step S2 The calculation formula is as follows: ； In the formula, This is the maximum voltage for electrostatic capture. This is the dust conductivity correction factor. Based on the calculated dust concentration, a voltage is applied to the electrostatic precipitator module inside the primary purification tower. Electrostatic collection is used to remove most of the SO2 and residual dust.

6. The method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas according to claim 1, characterized in that, Ozone generation in step S3 The calculation formula is as follows: ； In the formula, NO x The oxidation coefficient ranges from 0.8 to 1.

2. The instantaneous volumetric flow rate of the flue gas. NO x The target efficiency is set at 95%. The synergistic oxidation coefficient for VOCs ranges from 0.002 to 0.005m. 3 / mg, based on the calculation results, the ultraviolet photocatalytic module is activated to generate ozone, and the ozone generation amount is .

7. The method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas according to claim 1, characterized in that, Step S3: Injection amount of modified activated carbon The calculation formula is as follows: ； In the formula, The adsorption coefficient ranges from 0.001 to 0.

003. NO x The adsorption weight is 1.2-1.5, and β is the VOCs adsorption weight, with a value of 0.8-1.

0. This refers to the flue gas residence time, with a value of 12-15 seconds. The porosity of activated carbon is 0.7-0.

8. This represents the specific surface area of ​​activated carbon; based on the calculation results, it is calculated according to the injection rate. Spray-modified activated carbon.

8. The method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas according to claim 1, characterized in that, Step S4: Real-time monitoring of outlet pollutant concentration Calculate the compliance index With reflux trigger threshold The formula is as follows: ； ； In the formula, where: These are the weighting coefficients for each pollutant, and their sum is 1. The national standard limit is, This is a pressure loss correction factor, with a value ranging from 0.1 to 0.

2. For real-time pressure loss of the system, For the maximum permissible pressure loss; when At that time, the flue gas is directly discharged through the induced draft fan; when When the flue gas is returned to the primary purification tower for reprocessing, the return valve is automatically triggered, forming a closed-loop control.

9. The method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas according to claim 1, characterized in that, The modified quicklime powder is prepared by mixing quicklime powder with a magnesium sulfate solution of 5%-8% by mass at a solid-liquid ratio of 1:3, drying, and then calcining at 300-350℃ for 2 hours.

10. The method for staged purification and synergistic removal of pollutants from pre-pumped furnace flue gas according to claim 1, characterized in that, In step S3, a conical ash collection hopper is installed at the bottom of the secondary reaction tower, with the hopper wall inclined at an angle of not less than 60°. This hopper is used to collect unreacted modified activated carbon particles. After being screened to remove impurities, the particles can be returned to the secondary reaction tower for re-spraying, thus reducing material consumption.

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