CN206996259U - A kind of spuious flue gas during smelting wet dedusting of atm number, desulphurization system - Google Patents

Abstract

The utility model discloses a large-volume stray smelting flue gas wet dust removal and desulfurization system. The desulfurization agent is mainly absorbed by magnesium oxide, supplemented by sodium hydroxide, and the amount of sodium hydroxide added is adjusted in time according to the concentration of sulfur dioxide in the flue gas; the desulfurization absorption tower adopts an integrated structure of "absorption-dust removal-mist removal-evacuation"; Install a high-temperature flue gas cooling device at the entrance of the absorption tower; add a side stirring device and an aeration oxidation device at the bottom of the desulfurization absorption tower, which can effectively convert the slightly soluble magnesium sulfite in the absorption tower into easily soluble magnesium sulfate, avoiding the Deposition of insoluble matter such as soot and magnesium oxide impurities. The separation of insoluble matter and magnesium sulfate solution can be realized by adopting pressure filtration to the desulfurization liquid. The treatment cost is low and the effect is remarkable. It can meet the treatment of flue gas in special periods such as complex smelting flue gas high temperature period, atmospheric volume, high concentration sulfur dioxide emission, etc.

Description

A large amount of stray smelting flue gas wet dust removal and desulfurization system

technical field

The utility model belongs to the fields of smelting and chemical industry, and relates to a system for wet dust removal and desulfurization of stray smelting flue gas with large volume.

Background technique

During the smelting process, a large amount of low-concentration smelting stray flue gas containing SO ₂ is often produced, mainly including flue gas collected in the factory building during the production process of each kiln, flue gas from maintenance and heat preservation, and flue gas from entering and exiting materials. gas, low-concentration high-temperature smelting flue gas, etc. It is characterized by large gas volume, high-concentration periods dominated by low _- concentration SO2, and high-temperature periods dominated by low temperatures (normal flue gas temperature is about 40-55°C, and in special cases as high as 280°C), and the flue gas is accompanied by A large number and variety of toxic and harmful heavy metal substances. According to the provisions of the new environmental protection law, this kind of flue gas must be discharged up to the standard all the time, and the waste water produced must be treated up to the standard.

Traditionally, the method of segmented treatment is used for treatment. First, the complex flue gas is subjected to wet scrubbing pretreatment to remove the smoke and dust carried by the flue gas, lower the temperature, and then desulfurize, defog and empty the purified flue gas. This method has obvious effects, but the process is complicated, the equipment investment and operating costs are too high, the economy is not good, and a large amount of acidic wastewater is produced, and the treatment cost is high.

Utility model content

The purpose of this utility model is to aim at the deficiencies of the traditional process, combined with the characteristics of large volume, complex and low-concentration smelting flue gas, to provide a low-cost "absorption-dust-removal-mist removal" that uses magnesium oxide as a desulfurizer to process complex smelting flue gas -Emptying" integrated, full-time compliance management system.

The technical scheme of the utility model is: a large amount of stray smelting flue gas wet dust removal and desulfurization system, the system equipment includes: desulfurization absorption tower, flue gas conveying fan, mist eliminator, wet electrostatic precipitator, multi-layer Shower device, flow equalization efficiency tray, air spray gun, side stirring device, spray layer control valve, inlet SO2 concentration detector, outlet _SO2 concentration detector, absorption tower circulation pump, oxidation fan, _sodium hydroxide automatic control Regulating valve, sodium hydroxide storage tank, magnesium hydroxide slurry pump, magnesium hydroxide slurry tank, magnesium oxide aging pump, magnesium oxide aging tank, desulfurization liquid storage tank, filter press, desulfurization hydraulic filter pump, chimney, magnesium hydroxide Slurry spraying device; the flue gas conveying fan is installed at the front end of the inlet flue of the desulfurization absorption tower, the magnesium hydroxide slurry spraying device is installed at the flue gas inlet of the middle and lower part of the desulfurization absorption tower body, and the inlet SO ₂ concentration detector is installed on the flue gas inlet pipe The sodium hydroxide storage tank is connected to the lower part of the desulfurization absorption tower through pumps and pipelines, and the connected pipeline is equipped with a sodium hydroxide self _- control regulating valve. _The outlet SO2 concentration detector is set in the chimney, the inlet SO2 concentration detector and the outlet SO2 concentration detector. ₂ The concentration detectors are respectively interlocked with the signals of the sodium hydroxide self-control regulating valve; the inside of the desulfurization absorption tower is equipped with a demister, a multi-layer spray device, and a flow-equalizing efficiency tray from top to bottom; the desulfurization A wet electrostatic precipitator is installed above the mist eliminator inside the absorption tower body, and a chimney is arranged above the wet electrostatic precipitator; an oxidation aeration device is installed at the bottom of the desulfurization absorption tower, and the oxidation aeration device includes an oxidation fan, an air spray gun, an aeration Air main pipe, aeration air branch pipe, the aeration air main pipe is placed in the middle of the slurry layer in the tower, one end is connected to the oxidation fan, and the other end is connected to the air spray gun through the aeration oxidation branch pipe, and the bottom of the desulfurization absorption tower is also equipped with lateral stirring Device; the magnesium oxide aging tank is connected to the magnesium oxide aging pump through a pipeline, and the outlet of the magnesium oxide aging pump is connected to the magnesium hydroxide slurry tank, and the magnesium hydroxide slurry tank is the magnesium hydroxide slurry at the flue gas inlet through the magnesium hydroxide slurry pump. There is a valve on the pipeline for supplying liquid to the spraying device and replenishing magnesium hydroxide slurry for the desulfurization absorption tower and replenishing magnesium hydroxide slurry for the desulfurization absorption tower; the outlet of the circulation pump of the absorption tower located at the bottom of the desulfurization absorption tower is divided into two branches, One way is connected to the multi-layer spraying device, each layer is adjusted and controlled by the spray layer control valve, and the other way is connected to the desulfurization liquid storage tank with a valve on the connecting pipeline; the desulfurization liquid storage tank is passed through the desulfurization hydraulic filter pump and pressure filter. machine connection.

Preferably, the multi-layer spraying device has three layers.

Preferably, there are three sets of oxidation aeration devices, and the air spray guns are arranged on the same circumference at intervals of 120 degrees.

Preferably, there are three sets of lateral stirring devices, and the stirring blades are located below the air spray gun.

The technical effect of the utility model is: the desulfurization agent used in this system is mainly absorbed by magnesium hydroxide, supplemented by sodium hydroxide, and the amount of sodium hydroxide added is adjusted in time according to the concentration of SO2 in the flue gas _; The tower adopts an integrated structure of "absorption-dust removal-fog removal _- evacuation", which effectively integrates the functions of SO2 absorption, dust removal, fog removal, and emptying in the flue gas, shortens the process flow, and reduces one-time investment; desulfurization absorption A high-temperature flue gas cooling device is installed at the entrance of the tower, which increases the adaptability to intermittent high-temperature smelting flue gas; a side stirring device and an aeration oxidation device are added at the bottom of the desulfurization absorption tower, which can effectively make the slightly soluble sulfurous acid in the absorption tower Magnesium is fully converted into easily soluble magnesium sulfate, avoiding the deposition of insoluble matter such as soot and magnesium oxide impurities. The separation of insoluble matter and magnesium sulfate solution can be realized by adopting pressure filtration to the desulfurization liquid, and the magnesium sulfate clear liquid can be used for replenishment of sulfuric acid system or production of magnesium sulfate products.

This system uses magnesium hydroxide as a desulfurizer, and the full-time standard treatment method handles complex smelting flue gas, with low treatment cost and remarkable effect. It can meet the complex smelting flue gas high-temperature period, atmospheric volume, high-concentration SO2 emission and other special period flue gas treatment. It can effectively separate toxic and harmful heavy metals in desulfurization liquid and insoluble substances in magnesium oxide. Recovery of magnesium sulfate clear liquid can be It is used for supplementing water in sulfuric acid system or producing magnesium sulfate products, which has remarkable economic and environmental benefits.

Description of drawings

Fig. 1 is equipment composition and flow chart of the present invention;

In the figure, 1—desulfurization absorption tower; 2—flue gas conveying fan; 3—mist eliminator; 4—wet electrostatic precipitator; 5—multi-layer spraying device; ; 8—side stirring device; 9—spray layer control valve; 10—inlet SO ₂ concentration detector; 11—outlet SO ₂ concentration detector; 12—absorption tower circulation pump; 13—oxidation fan; 14—hydrogen oxidation Sodium self-control regulating valve; 15—sodium hydroxide storage tank; 16—magnesium hydroxide slurry pump; 17—magnesium hydroxide slurry tank; 18—magnesia aging pump; 19—magnesia aging tank; 20—desulfurization liquid storage tank; 21—filter press; 22—hydraulic filter pump for desulfurization; 23—chimney; 24—magnesium hydroxide slurry spraying device.

detailed description

The technical solution of the present invention will be further described in conjunction with the accompanying drawings.

As shown in the figure, a large amount of stray smelting flue gas wet dedusting and desulfurization system, the equipment set up in the processing process includes: desulfurization absorption tower 1, flue gas conveying fan 2, mist eliminator 3, wet electrostatic precipitator 4 , multi-layer spray device 5, flow equalization and efficiency improvement tray 6, air spray gun 7, side stirring device 8, spray layer control valve ₉ , inlet SO2 concentration detector 10, outlet SO2 concentration detector ₁₁ , absorption Tower circulation pump 12, oxidation fan 13, sodium hydroxide self-control regulating valve 14, sodium hydroxide storage tank 15, magnesium hydroxide slurry pump 16, magnesium hydroxide slurry tank 17, magnesium oxide aging pump 18, magnesium oxide aging tank 19, Desulfurization liquid storage tank 20, filter press 21, desulfurization hydraulic filter pump 22, chimney 23, magnesium hydroxide slurry spray device 24; flue gas conveying fan 2 is installed at the front end of the entrance flue of desulfurization absorption tower 1, and the tower body of desulfurization absorption tower 1 A magnesium hydroxide slurry spray device 24 is installed at the flue gas inlet in the middle and lower part, an inlet SO2 concentration detector ₁₀ is installed on the flue gas inlet pipe, and the sodium hydroxide storage tank 15 is connected to the lower part of the desulfurization absorption tower 1 through a pump and a pipeline. The pipeline is provided with a sodium hydroxide self-control regulating valve 14, the outlet SO2 concentration detector ₁₁ is located in the chimney 23, the inlet SO2 concentration detector ₁₀ and the outlet SO2 concentration detector ₁₁ are respectively connected with the sodium hydroxide self-control regulating valve 14 signal Interlocking; the inside of the desulfurization absorption tower 1 is equipped with a demister 3, a multi-layer spray device 5, and a flow-equalizing efficiency tray 6 from top to bottom; the defogging inside the desulfurization absorption tower 1 A wet electrostatic precipitator 4 is arranged above the device 3, and a chimney 23 is arranged above the wet electrostatic precipitator; an oxidation aeration device is arranged at the bottom of the desulfurization absorption tower 1, and the oxidation aeration device includes an oxidation blower 13, an air spray gun 7, an aeration air Main pipe, aeration air branch pipe, the main pipe of aeration air is placed in the middle of the slurry layer in the tower, one end is connected to the oxidation fan 13, and the other end is connected to the air spray gun 7 through the aeration oxidation branch pipe. The bottom of the desulfurization absorption tower 1 is also provided with a lateral Stirring device 8; Magnesium oxide ripening tank 19 is connected with magnesium oxide ripening pump 18 by pipeline, and described magnesium oxide ripening pump 18 outlets are connected to magnesium hydroxide slurry tank 17, and magnesium hydroxide slurry tank 17 is by magnesium hydroxide slurry pump 16 The magnesium hydroxide slurry spraying device 24 at the flue gas inlet is used to supply liquid to the desulfurization absorption tower 1 to supplement the magnesium hydroxide slurry, and a valve 25 is provided on the pipeline for replenishing the magnesium hydroxide slurry to the desulfurization absorption tower 1; The outlet of the absorption tower circulation pump 12 is divided into two branches, one of which is connected to the multi-layer spray device 5, each layer is adjusted and controlled by the spray layer control valve 9, and the other is connected to the desulfurization liquid storage tank 20 and connected to the pipeline A valve is provided; the desulfurization liquid storage pool 20 is connected to a filter press 21 through a desulfurization hydraulic filter pump 22 .

The process flow includes: After the large amount of stray smelting flue gas is pressurized by the flue gas conveying fan 2, after being pretreated by the magnesium hydroxide slurry spraying device 24, it enters the tower body from the middle and lower part of the desulfurization absorption tower 1, and is extracted by equal flow. The effect tray 6 is in reverse contact with the magnesium hydroxide slurry from the multi-layer spraying device 5 for desulfurization, and the desulfurized flue gas is demisted by the demister 3 and the wet electrostatic precipitator 4, and then emptied through the upper chimney 23 on the top of the tower ; In the desulfurization absorption tower 1 tower tank, the magnesium hydroxide slurry is fully stirred by the lateral stirring device 8, effectively preventing the deposition of insoluble particles, and the magnesium sulfite formed after desulfurization is gradually generated under the oxidation of the oxidation aeration device Magnesium sulfate solution with high solubility; inlet SO2 concentration detector ₁₀ and outlet SO2 concentration detector ₁₁ are respectively interlocked with sodium hydroxide self _- control regulating valve ₁₄ signal, when inlet SO2 concentration or outlet SO2 concentration exceeds the set value , automatically open the sodium hydroxide self-control regulating valve 14, and add sodium hydroxide solution to the desulfurization absorption tower 1 to ensure that the flue gas is discharged up to the standard; the absorption tower circulation pump 12 transports the magnesium hydroxide slurry in the tower to the three-layer spray device 5, hydrogen The magnesium oxide slurry is regulated and controlled by the spray layer control valve 9 that each layer has respectively, and the number of spraying layers can be adjusted according to the stray smelting flue gas SO2 concentration and gas volume _; when the magnesium hydroxide slurry tends to be saturated, It is transported to the desulfurization liquid storage pool 20 through the absorption tower circulation pump 12 (open the valve on the pipe connected to the desulfurization liquid storage pool 20, and the valve is closed when the magnesium hydroxide slurry is not saturated), and the slurry entering the desulfurization liquid storage pool 20 is desulfurized The hydraulic filter pump 22 is transported to the filter press 21 for pressure filtration. The rich in toxic and harmful insoluble substances are processed separately as filter cakes. The magnesium sulfate clear liquid can be used as water replenishment in the sulfuric acid system or the production of magnesium sulfate products; qualified magnesium oxide is purchased The powder is unloaded into the magnesia aging tank 19 and water is added, and the slaking is carried out under steam heating and stirring conditions. After the slaking is qualified, the magnesia slaking pump 18 is transported to the magnesium hydroxide slurry tank 17 for use, and the magnesium hydroxide slurry pump 16 Transport it to the magnesium hydroxide slurry spraying device 24 at the entrance of the flue gas to pretreat the flue gas. At the same time, according to the discharge of saturated desulfurization liquid, open the valve on the liquid inlet pipe in time to supplement the slurry in the desulfurization absorption tower 1.

Further, there are three sets of oxidation aeration devices, and the air spray guns 7 are arranged on the same circle at intervals of 120 degrees, so that the oxidation is faster and more uniform.

Further, there are three sets of lateral stirring devices 8 , and the stirring blades are located below the air spray gun 7 and cooperate with the air spray gun 7 .

Example 1

Preparation of magnesium hydroxide slurry: First, add the purchased qualified magnesium oxide powder and fresh water into the magnesium oxide aging tank 19 in a certain proportion, pass steam, start stirring, and aging for 2 hours to make 12% magnesium hydroxide slurry, which is oxidized The magnesium slaking pump 18 is delivered to the magnesium hydroxide slurry tank 17 for use. During normal production, the side stirring device 8 is turned on, the oxidation aeration device is turned on, and air is blown in by the air spray gun 7 . Turn on the absorption tower circulation pump 12 to deliver the magnesium hydroxide slurry to the multi-layer spray device 5, adjust the spray layer control valve 9, and open the three layers for spraying. Smelting stray flue gas (gas volume is about 600,000 Nm ³ /h, SO ₂ concentration is 1057-3500mg/Nm ³ , average is about 3000mg/Nm ³ , temperature 50±10°C) is pressurized by flue gas conveying fan 2, It enters the tower body from the middle and lower part of the desulfurization absorption tower 1, and after being evenly distributed through the flow-equalizing efficiency tray 6, it is in reverse contact with the magnesium hydroxide slurry from the top to bottom of the multi-layer spraying device 5, and the magnesium hydroxide slurry absorbs the flue gas. of SO ₂ absorption. After desulfurization, the flue gas is demisted by the mist eliminator 3 and the wet electrostatic precipitator 4, and then emptied through the upper chimney 23 on the top of the tower. The constant detection by the outlet SO ₂ concentration detector 11 shows that the SO ₂ concentration is basically maintained at 150 mg/Nm ³ , which meets the discharge standard. The desulfurization slurry in the tower has a low solid content, no sediment sinks to the bottom of the tower, and all pipes are free from clogging. When the pH of the magnesium hydroxide slurry reaches 6, the absorption tower circulating pump 12 transports the saturated liquid to the desulfurization liquid storage tank 20, and when the saturated desulfurization liquid in the desulfurization absorption tower 1 is discharged to a high liquid level of 0.5 meters, the delivery of the saturated liquid is stopped, and the hydrogen oxidization The magnesium slurry pump 16 replenishes the magnesium hydroxide slurry to the desulfurization absorption tower 1 to meet the process requirements. When the desulfurization liquid storage tank 20 reaches a certain level, turn on the desulfurization hydraulic filter pump 22 to transport the desulfurization liquid to the filter press 21 for pressure filtration. The rich in toxic and harmful insoluble substances are treated as filter cakes separately, and the magnesium sulfate clear liquid can be used as sulfuric acid Production of system rehydration or magnesium sulfate products.

Example 2

During abnormal production, the amount of smelting stray flue gas is about 400,000 Nm ³ /h, the concentration of SO ₂ is 6000-8500mg/Nm ³ , the average is about 7000mg/Nm ³ , and the temperature is 200-280℃. The side stirring device 8 is turned on, the oxidation aeration device is turned on, and air is blown in by the air spray gun 7 . Turn on the magnesium hydroxide slurry pump 16, deliver the magnesium hydroxide slurry to the magnesium hydroxide slurry spray device 24 at the flue gas inlet to spray the flue gas to cool down, turn on the absorption tower circulation pump 12 to deliver the magnesium hydroxide slurry to the spray layer 5, adjust Each layer of spray layer control valve 9 is opened to spray on the second floor. After the smelting stray flue gas is pressurized by the flue gas conveying fan 2, after being cooled and washed by the magnesium hydroxide slurry spraying device 24, it enters the tower body from the middle and lower part of the desulfurization absorption tower 1, and is evenly distributed by the flow-balancing efficiency tray 6 It is in reverse contact with the magnesium hydroxide slurry from top to bottom from the multi-layer spray device ₅ , and the magnesium hydroxide slurry absorbs SO2 in the flue gas. After desulfurization, the flue gas is demisted by the mist eliminator 3 and the wet electrostatic precipitator 4, and then emptied through the upper chimney 23 on the top of the tower. When the inlet SO2 concentration exceeds the set value of _6500mg / ^Nm3 or the outlet SO2 concentration exceeds 150mg/ ^Nm3 , the sodium hydroxide self-control regulating valve 14 is automatically opened after a delay of ₂ seconds, and sodium hydroxide is added to the desulfurization absorption tower 1. _The outlet SO2 concentration detector ₁₁ detects that the SO2 concentration is basically maintained at 150mg/ ^Nm3 , and the discharge meets the standard; when the pH of the magnesium hydroxide slurry reaches 6, the absorption tower circulation pump 12 transports the saturated liquid to the desulfurization liquid storage tank 20, when When the saturated desulfurization liquid in the desulfurization absorption tower 1 is discharged to a high liquid level of 0.5 meters, the delivery of the saturated liquid is stopped, and the magnesium hydroxide slurry pump 16 replenishes the magnesium hydroxide slurry to the desulfurization absorption tower 1 to meet the process requirements. When the desulfurization liquid storage tank 20 reaches a certain liquid level, turn on the desulfurization hydraulic filter pump 22 to send the desulfurization liquid to the filter press 21 for pressure filtration. The rich in toxic and harmful insoluble substances are treated as filter cakes separately, and the magnesium sulfate clear liquid can be used as a sulfuric acid system. Manufacture of hydration or magnesium sulfate products.

Example 3

During abnormal production, the amount of smelting stray flue gas is about 400,000 Nm ³ /h, the concentration of SO ₂ is 835-2500mg/Nm ³ , the average is about 2000mg/Nm ³ , and the temperature is 50±10℃. The side stirring device 8 is turned on, the oxidation aeration device is turned on, and air is blown in by the air spray gun 7 . Turn on the absorption tower circulation pump 12 to deliver the magnesium hydroxide slurry to the spray layer 5, adjust the single-layer spray layer control valve 9, and open the second layer for spraying. After being pressurized by the flue gas conveying fan 2, the stray flue gas from smelting enters the tower body from the middle and lower part of the desulfurization absorption tower 1. _The magnesium hydroxide slurry is in reverse contact, and the magnesium hydroxide slurry absorbs SO2 in the flue gas. After desulfurization, the flue gas is demisted by the mist eliminator 3 and the wet electrostatic precipitator 4, and then emptied through the upper chimney 23 on the top of the tower. The constant detection by the outlet SO ₂ concentration detector 11 shows that the SO ₂ concentration is basically maintained at 150 mg/Nm ³ , which meets the discharge standard. The desulfurization slurry in the tower has a low solid content, no sediment sinks to the bottom of the tower, and all pipes are free from clogging. When the pH of the magnesium hydroxide slurry reaches 6, the absorption tower circulating pump 12 transports the saturated liquid to the desulfurization liquid storage tank 20, and when the saturated desulfurization liquid in the desulfurization absorption tower 1 is discharged to a high liquid level of 0.5 meters, the delivery of the saturated liquid is stopped, and the hydrogen oxidization The magnesium slurry pump 16 replenishes the magnesium hydroxide slurry to the desulfurization absorption tower 1 to meet the process requirements. When the desulfurization liquid storage tank 20 reaches a certain liquid level, turn on the desulfurization hydraulic filter pump 22 to send the desulfurization liquid to the filter press 21 for pressure filtration. The rich in toxic and harmful insoluble substances are treated as filter cakes separately, and the magnesium sulfate clear liquid can be used as a sulfuric acid system. Manufacture of hydration or magnesium sulfate products.

Claims (4)

1. A large amount of stray smelting flue gas wet dust removal and desulfurization system, characterized in that: the system equipment includes: desulfurization absorption tower (1), flue gas conveying fan (2), mist eliminator (3), wet type Electrostatic precipitator (4), multi-layer spraying device (5), flow equalization efficiency tray (6), air spray gun (7), side stirring device (8), spray layer control valve (9), inlet SO2 concentration detector ( ₁₀ ), outlet SO2 concentration detector ( ₁₁ ), absorption tower circulation pump (12), oxidation fan (13), sodium hydroxide self-control regulating valve (14), sodium hydroxide storage tank (15 ), magnesium hydroxide slurry pump (16), magnesium hydroxide slurry tank (17), magnesium oxide aging pump (18), magnesium oxide aging tank (19), desulfurization liquid storage tank (20), filter press (21) , desulfurization hydraulic filter pump (22), chimney (23), magnesium hydroxide slurry spray device (24); flue gas conveying fan (2) is installed at the front end of the inlet flue of desulfurization absorption tower (1), desulfurization absorption tower (1) A magnesium hydroxide slurry spray device (24) is installed at the flue gas inlet in the middle and lower part of the tower body, an inlet SO2 concentration detector ( ₁₀ ) is installed on the flue gas inlet pipe, and the sodium hydroxide storage tank (15) is connected to the gas inlet through a pump and a pipeline. The lower part of the desulfurization absorption tower (1) and the connected pipeline are equipped with a sodium hydroxide self-control regulating valve (14), the outlet SO2 concentration detector ( ₁₁ ) is installed in the chimney (23), and the inlet SO2 concentration detector ( ₁₀ ) and the outlet SO2 concentration detector ( ₁₁ ) are respectively interlocked with the signal of the sodium hydroxide self-control regulating valve (14); the inside of the desulfurization absorption tower (1) is respectively equipped with a demister (3), multiple Layer spraying device (5), efficiency-equalizing tray (6); wet electrostatic precipitator (4) is installed above the demister (3) inside the tower body of the desulfurization absorption tower (1), and the wet electrostatic precipitator Above is the chimney (23); the bottom of the desulfurization absorption tower (1) is provided with an oxidation aeration device, and the oxidation aeration device includes an oxidation fan (13), an air spray gun (7), an aeration air main pipe, and an aeration air branch pipe , the aeration air main pipe is placed in the middle of the slurry layer in the tower, one end is connected to the oxidation fan (13), the other end is connected to the air spray gun (7) through the aeration oxidation branch pipe, and the bottom of the desulfurization absorption tower (1) is also provided with a lateral The stirring device (8); the magnesium oxide aging tank (19) is connected to the magnesium oxide aging pump (18) through a pipeline, and the outlet of the magnesium oxide aging pump (18) is connected to the magnesium hydroxide slurry tank (17), and the magnesium hydroxide slurry The tank (17) supplies liquid to the magnesium hydroxide slurry spraying device (24) at the flue gas inlet and supplements the magnesium hydroxide slurry to the desulfurization absorption tower (1) through the magnesium hydroxide slurry pump (16) and is the desulfurization absorption tower (1) There is a valve (25) on the pipeline for supplementing the magnesium hydroxide slurry; the outlet of the absorption tower circulation pump (12) located at the bottom of the desulfurization absorption tower (1) is divided into two branches, all of which are connected to the multi-layer spraying device (5) , each layer is adjusted and controlled by the spray layer control valve (9), and the other road is connected to the desulfurization liquid storage tank (20) and a valve is set on the connecting pipeline; the desulfurization liquid storage tank (20 ) is connected with the filter press (21) through the desulfurization hydraulic filter pump (22). 2. A wet dedusting and desulfurization system for stray large-scale smelting flue gas according to claim 1, characterized in that: the multi-layer spraying device (5) has three layers. 3. A large amount of stray smelting flue gas wet dust removal and desulfurization system according to claim 1, characterized in that: three sets of oxidation aeration devices are installed, and the air spray guns (7) are separated by 120 on the same circle. layout. 4. A large amount of stray smelting flue gas wet dedusting and desulfurization system according to claim 1, characterized in that: there are three sets of side stirring devices (8), and the stirring blades are located in the air spray gun (7) below.