KR101876413B1 - FLUE GAS TREATMENT APPARATUS FOR REMOVING NOx and SOx SIMULTANEOUSLY - Google Patents

Abstract

The present invention relates to an apparatus for effectively simultaneously removing nitrogen oxides and sulfur oxides from exhaust gas generated by combustion of fossil fuels in various power plants, steel mills, and the like, and more particularly, to an apparatus for simultaneously removing nitrogen oxides and sulfur oxides from the flue gas, which can simultaneously treat the nitrogen oxides and sulfur oxides contained in the flue gas through a gas-liquid reaction in which ozone is supplied to the exhaust gas to be supplied, nitrogen monoxide of the exhaust gas is reduced to nitrogen dioxide by an oxidation catalytic reaction and an aqueous alkaline solution is injected into the exhaust gas.

Description

TECHNICAL FIELD [0001] The present invention relates to an apparatus for simultaneously removing nitrogen oxides and sulfur oxides from an exhaust gas,

The present invention relates to an apparatus for simultaneously removing nitrogen oxides and sulfur oxides from exhaust gases generated by combustion of fossil fuels in various power plants and steel mills, and more particularly, to an apparatus for supplying ozone to an exhaust gas to be supplied, A simultaneous removal of nitrogen oxides and sulfur oxides in the exhaust gas which can simultaneously treat nitrogen oxides and sulfur oxides contained in the exhaust gas through the gas-liquid reaction in which the nitrogen monoxide in the exhaust gas is reduced to nitrogen dioxide and the alkaline aqueous solution is injected into the exhaust gas .

Generally, in various power plants and steel mills, a large exhaust gas treatment apparatus is used to treat nitrogen oxides and sulfur oxides which are harmful air pollutants of exhaust gas generated by combustion of fossil fuels and the like.

The exhaust gas treatment apparatus treats the sulfur oxides of the exhaust gas with a flue gas desulfurization (FGD) or the like, and treats the nitrogen oxide of the exhaust gas with a selective catalytic reduction (SCR) or the like.

At this time, the flue gas desulfurization apparatus is an apparatus for removing sulfur dioxide (SO ₂ ) in a combustion exhaust gas through flue gas desulfurization. In the flue gas desulfurization method, SO ₂ is absorbed into an alkali solution, a metal oxide, ₂ is adsorbed and removed. In addition, the selective reduction catalyst apparatus is a system in which urea solution or the like is used as an oxidizing agent, and the nitrogen oxide is reduced in the presence of a catalyst, purified by nitrogen gas or the like, and discharged.

However, since the flue gas desulfurization apparatus and the selective reduction catalyst apparatus sequentially process the two processes of desulfurization and denitrification, in which a large amount of exhaust gas is completely different, the pollutants contained in the exhaust gas are treated, In addition, in the case of the flue gas desulfurization apparatus, the overall facility size is increased and the back pressure is increased. Therefore, in the case of the selective reduction catalyst apparatus, It is necessary to use a catalyst having a difficult operating condition and an expensive catalyst, so that the facility cost is excessively consumed.

As a conventional technique related to such an exhaust gas treating apparatus, Japanese Unexamined Patent Application Publication No. 10-2015-0108423 discloses an exhaust gas purifying apparatus for purifying SOx and NOx from exhaust gas containing SOx, NOx, soot and water vapor originating from combustion of fuel generated in an internal combustion engine. A cleaning device for removing the cleaning liquid is disclosed.

The technique comprises at least one catalytic reactor fluidly connected to an internal combustion engine, wherein the catalytic reactor converts at least SO ₂ to SO ₃ and NO to NO ₂ , Wherein the apparatus further comprises a condenser fluidly connected to the catalytic reactor below the catalytic reactor. The exhaust gas discharged from the condenser is cooled to a temperature lower than the dew point temperature of water in the condenser to condense SO ₃ , NO _2, and water, dissolve SO ₃ and NO ₂ in the condensed water, And NOx are removed from the exhaust gas.

Also, as one of the techniques for removing nitrogen oxides and sulfur oxides contained in the exhaust gas, Japanese Patent Application Laid-Open No. 10-1544280 discloses a chamber for forming an inlet through which exhaust gas flows and an outlet through which purified gas flows out; A sulfuric acid processing unit mounted in the chamber and spraying fine ozonated water droplets supplied from the fine ozonated water droplet supplying unit to treat sulfur oxides (SOx); And a nitrogen oxide processing unit mounted in the chamber and spraying a reducing agent to treat nitrogen oxides (NOx) contained in the exhaust gas passed through the sulfur oxide processing unit, wherein the fine ozonated water droplets ejected from the sulfur oxide processing unit And the ozone (O ₃ ), the water treats the sulfur oxides (SOx) contained in the exhaust gas and the ozone reacts with the nitrogen monoxide NO contained in the exhaust gas to generate nitrogen dioxide (NO ₂ ) And the efficiency of the desulfurization reaction in which an effective reaction is performed at a temperature of 100 ° C or lower is obtained by using the exhaust gas treatment apparatus using the fine ozonated water droplet And the fine ozonated water droplets were separated into ozone and water, and then sulfur oxides and nitrogen oxides in the exhaust gas It is adapted to each of the reaction it falls as the overall processing efficiency of the response delay in accordance with this as there is a problem in that the re-use of a reducing agent increases the processing cost difficult.

KR 10-2015-0108423 A (May 25, 2015) KR 10-1544280 B1 (Aug. 06, 2015)

SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the above problems, and it is an object of the present invention to provide an ozone generator which supplies ozone to an exhaust gas discharged from a power plant or a steel mill through an ozone generator, The exhaust gas passing through the oxidation catalyst is supplied to the wet scrubber, and nitrogen oxides and nitrogen oxides contained in the exhaust gas are brought into contact with the aqueous alkaline solution through the plurality of spray tubes. And a removal device capable of simultaneously treating sulfur oxides.

Another object of the present invention is to provide an apparatus for simultaneously removing nitrogen oxides and sulfur oxides of an exhaust gas which can appropriately maintain the pH of an aqueous alkaline solution injected through a spray tube.

In order to solve the above problems, an apparatus for simultaneously removing nitrogen oxides and sulfur oxides according to the present invention includes: an ozone supply unit for supplying ozone to exhaust gas transported along a duct; An oxidation catalyst for promoting the reaction of nitrogen monoxide and ozone in the exhaust gas with passage of exhaust gas mixed with ozone to produce nitrogen dioxide; And an alkaline aqueous solution storage portion is vertically communicated with the lower portion thereof. The exhaust gas having passed through the oxidation catalyst flows into the lower portion of the gas-liquid reaction portion and contacts the alkaline aqueous solution into which the introduced exhaust gas is sprayed A wet scrubber for removing nitrogen oxides and sulfur oxides included in the exhaust gas; An alkaline aqueous solution supply unit for spraying the alkaline aqueous solution to the gas-liquid reaction unit; An alkali medicament supply unit for supplying the alkaline medicament to the alkaline aqueous solution storage unit; And an agitator for agitating the alkaline aqueous solution stored in the alkaline aqueous solution storage part, the alkaline solution supplied from the alkaline aqueous solution supplying part, and water.

Here, the ozone supply unit may include an ozone generator and a chlorine ion water storage tank storing chlorate ions, and the ozone generated by the ozone generator may be supplied through the chlorine ion water stored in the chlorine ionized water storage tank.

In the wet scrubber, a plurality of through holes are formed in the circular plate, and a perforated plate is installed to diffuse the exhaust gas introduced into the gas-liquid reaction part and induce the exhaust gas to rise up.

According to the present invention, gaseous ozone is supplied from an ozone generator to exhaust gas from a power plant or a steel mill carried along a duct, and then passes through an oxidation catalyst to promote the reaction of nitrogen monoxide and ozone as an oxidizer in the exhaust gas And the exhaust gas passed through the oxidation catalyst is brought into contact with the aqueous alkaline solution in the gas-liquid reaction part of the wet scrubber, so that the nitrogen oxide and the sulfur oxide contained in the exhaust gas can be treated simultaneously at the same time .

Further, the alkali aqueous solution continuously supplied with the alkali chemicals from the alkali chemical storage tank is advantageous in that the treatment efficiency can be improved while the processing cost can be reduced by maintaining the pH suitable for the removal of nitrogen oxides and sulfur oxides to be constant .

1 is a schematic view of an apparatus for simultaneously removing nitrogen oxides and sulfur oxides of an exhaust gas according to the present invention.
2 is a schematic view showing an operating state of an apparatus for simultaneously removing nitrogen oxides and sulfur oxides of an exhaust gas according to the present invention.
3 is a schematic cross-sectional view of an ozone supply unit applied to an apparatus for simultaneously removing nitrogen oxides and sulfur oxides according to the present invention.
4 is a graph showing the removal efficiency of nitrogen compounds (NOx) according to the concentration of O ₃ injected by an ozone supply unit in an apparatus for simultaneously removing nitrogen oxides and sulfur oxides of an exhaust gas according to the present invention.
5 is a perspective view of a perforated plate installed in a gas-liquid reaction part of a wet scrubber in an apparatus for simultaneously removing nitrogen oxides and sulfur oxides of an exhaust gas according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

The present invention relates to a method and apparatus for simultaneously supplying nitrogen oxide and sulfur oxide contained in an exhaust gas through a gas-liquid reaction in which ozone is supplied to an exhaust gas and the nitrogen monoxide of the exhaust gas is reduced to nitrogen dioxide by an oxidation catalyst reaction, And a device for simultaneously removing nitrogen oxides and sulfur oxides from the exhaust gas that can be treated.

FIG. 1 is a schematic view of an apparatus for simultaneously removing nitrogen oxides and sulfur oxides of an exhaust gas according to the present invention, and FIG. 2 is a schematic diagram showing an operating state of an apparatus for simultaneously removing nitrogen oxides and sulfur oxides according to the present invention.

1 and 2, an apparatus 1 for removing nitrogen oxides and sulfur oxides from exhaust gas according to the present invention is a device for removing nitrogen oxides and sulfur oxides in exhaust gas generated by combustion of fossil fuels in a power plant, The overall configuration includes an ozone supply unit 20, an oxidation catalyst 30, a wet scrubber 40, an alkaline aqueous solution supply unit 50, and an electrolytic water supply unit 50. The ozone supply unit 20 supplies ozone to the exhaust gas conveyed along the duct 10, An alkaline drug supply unit 60, and an agitator 70. [

An ozone supply unit 20 for supplying ozone with an oxidant to the duct 10 and an oxidation catalyst 20 for promoting the reaction between nitrogen monoxide and ozone in the exhaust gas while passing through the exhaust gas mixed with ozone An upper portion of the gas-liquid reacting portion 41 and a lower portion of the alkaline aqueous solution storing portion 43 are vertically communicated with each other and an exhaust gas passing through the oxidation catalyst 40 is supplied to the lower portion of the gas- And is circulated by the circulation pump 55 from the alkaline aqueous solution storage part 43 through the plurality of spray tubes 51 installed vertically and vertically in the upper part of the inside of the gas-liquid reaction part 41 A wet scrubber 40 for spraying the supplied alkali aqueous solution into the exhaust gas to treat nitrogen oxides and sulfur oxides included in the exhaust gas, and a liquid scrubber 40 connected to the upper part of the gas liquid reacting unit 41 of the wet scrubber 40 through a discharge pipe An exhaust fan 45 for sucking and exhausting the exhaust gas from which the nitrogen oxides and sulfur oxides have been removed through the gas-liquid reacting section 41; and an air- And an alkaline drug supply unit 60 for supplying the alkaline medicine contained in the alkaline drug storage tank 61 to the alkaline aqueous solution storage unit 43 by the drug supply pump 63 so as to maintain a constant pH suitable for the removal .

The ozone supply unit 20 is a conventional apparatus for generating ozone O _{3 and} supplying generated ozone to the duct 10. As shown in FIGS. 1 and 2, And supplies ozone onto the duct 10 of the exhaust gas conveyed including nitrogen oxide (NOx) and sulfur oxides (SOx).

That is, the gaseous ozone generated from the ozone supply unit 20 is supplied to and mixed with the exhaust gas transported along the duct 10, and the ozone generated in the ozone supply unit 20, And reacts with nitrogen monoxide (NO) in the exhaust gas while acting as an oxidizing agent to generate nitrogen dioxide (NO ₂ ).

In this process, ozone (O ₃ ) supplied to the duct (10) can generate nitrogen trioxide (N ₂ O ₃ ) and nitrogen dioxide (N ₂ O ₅ ) upon reaction with nitrogen monoxide (NO).

The above chemical reaction formula is shown in the following chemical formula 1.

(1)

1-1) NO + O ₃ ? NO ₂ + O ₂

1-2) 2NO + O ₃ ? N ₂ O ₃ + O ₂

1-3) 2NO + 2O ₃ ? N ₂ O ₅ + 3 / 2O ₂

Nitrogen in the oxide (NOx) is not soluble in water, the NO _2, N ₂ O ₃ and N ₂ O ₅ in combination with ozone, it was soluble in water, as HNO ₂ and HNO _3, etc. by a combination of the water And acidified.

Here, the ozone supplied through the ozone supply unit 20 may include chlorate ions (ClO < ^- >).

3 is a schematic cross-sectional view of an ozone supply unit applied to an apparatus for simultaneously removing nitrogen oxides and sulfur oxides according to the present invention.

3, the ozone supply unit 20 includes an ozone generator 21 and a chlorine ion water storage tank 23 storing chlorate ions. The ozone generator 21 generates ozone, And is supplied through the chlorine ion water stored in the chlorine ionized water storage tank (23).

At this time, the chlorate ion may be composed of sodium hypochlorite (NaClO), sodium hypochlorite (NaClO ₂ ), sodium chloride (NaClO ₃ ) and the like.

4 is a graph showing the removal efficiency of nitrogen compounds (NOx) according to the concentration of O ₃ injected by the ozone supply unit in the apparatus for simultaneously removing nitrogen oxides and sulfur oxides according to the present invention.

Referring to FIG. 4, when the concentration of ozone (O ₃ ) is 0.5 mol, the NO x removal efficiency is about 72%. When the concentration of ozone (O ₃ ) is 0.2 mol, (NOx) removal efficiency was about 50%. That is, there may be a saturation point of ozone, but the higher the concentration of ozone is, the higher the removal efficiency of nitrogen oxides (NOx) is.

At this time, while ozone (O ₃ ) concentration was maintained at 0.2 mol, ozone passing through sodium chlorate (NaClO ₂ ) showed about 78% of NO x removal efficiency. That is, the ozone passing through the chlorate ion was found to have high NOx removal efficiency even if the concentration was low.

Accordingly, when the ozone generated in the ozone generator 21 is supplied through the chlorine ion water, the concentration of ozone can be lowered.

The oxidation catalyst 30 serves as an accelerator for promoting the reaction between ozone (O ₃ ) and nitrogen oxide (NO x). When the exhaust gas mixed with ozone passes, the reaction of nitrogen oxide and ozone in the exhaust gas .

The oxidation catalyst 30 is a carrier in which numerous pores are densely formed. Various catalytic materials such as vanadium, zeolite, platinum and palladium are selectively coated on the inner peripheral surface of the pores In the process of passing the exhaust gas mixed with ozone through the pores of the oxidation catalyst 30, the reaction rate is promoted by the catalyst material, so that the nitrogen oxide contained in the exhaust gas reacts with the ozone in a short time to generate nitrogen dioxide.

The length of the duct 10 is relatively long due to the oxidation catalyst 30 because the reaction between the ozone O ₃ and the nitrogen oxides takes a long time and the duct 10 has to be long enough. As shown in FIG. Accordingly, there is an advantage that the overall volume of the apparatus for simultaneously removing nitrogen oxides and sulfur oxides of the exhaust gas according to the present invention can be reduced.

1 to 4, the wet scrubber 40 functions to treat nitrogen oxides and sulfur oxides contained in the exhaust gas by spraying an alkaline aqueous solution into the exhaust gas. The upper part of the wet scrubber 40 has a gas-liquid reaction part 41 And an alkaline aqueous solution storage part 43 is provided at a lower part thereof. The gas-liquid reaction part 41 and the alkaline aqueous solution storage part 43 are vertically communicated with each other.

The exhaust gas passing through the oxidation catalyst 30 is introduced into the wet scrubber 40 through the lower part of the gas-liquid reaction part 41 and is raised to the upper part of the wet scrubber 40. The upper part of the exhaust gas collects the gas- And a perforated plate 47 is provided on the inside thereof.

The wet scrubber 40 is formed as a vertically long tower.

5 is a schematic view of a device for simultaneously removing nitrogen oxides and sulfur oxides in the exhaust gas according to the present invention. Referring to FIG. 5, Liquid reaction part of the wet scrubber.

5, the perforated plate 47 is provided with a plurality of through holes in the circular plate, and the introduced exhaust gas is diffused to the upper portion of the gas-liquid reaction part 41 through the through holes formed in the perforated plate do.

5, the plurality of through holes H are thoroughly drilled as a whole, and the exhaust gas flowing from the inner lower part of the gas-liquid reaction part 41 Is uniformly diffused and moved upward by the perforated plate (47).

The wet scrubber 40 is provided with an alkali aqueous solution supply unit 50 for treating nitrogen oxides and sulfur oxides included in the exhaust gas diffused and raised in the above configuration.

The alkaline aqueous solution supply unit 50 includes a spray tube 51, a spray nozzle 53, and a circulation pump 55.

The injection pipe 51 is installed in the gas-liquid reaction part 41 in a multi-stage manner so as to be vertically spaced apart from each other by a predetermined distance, and the injection nozzle 53 is installed in the injection pipe 51. The circulation pump 55 pumps the aqueous alkaline solution contained in the alkaline aqueous solution storage unit 43 and supplies the alkaline aqueous solution to the spray tube 51.

Here, the injection nozzle 53 may be provided in the zigzag direction on the upper surface, the lower surface and the side surface of the spray tube 51, and may be constituted by a mist spray nozzle capable of spraying the sprayed alkali solution in a mist form .

Thus, the alkali solution pumped by the circulation pump 55 is injected by the injection nozzle 53 through the injection pipe 51, and the injected alkali solution reacts with the nitrogen oxide and the sulfur oxide contained in the exhaust gas It is converted into various salts and treated.

Further, in the wet scrubber 40, nitrogen oxides converted into nitrogen dioxide, nitrogen trioxide, and nitrogen oxide by the reaction of the exhaust gas and the aqueous alkali solution by the reaction of the exhaust gas and the aqueous alkali solution react with water to convert nitrite (HNO ₂ ) (HNO ₃ ) and sulfur oxides such as nitric acid (HNO ₂ ), nitric acid (HNO ₃ ) and sulfur dioxide (SO ₂ ) react with the alkali solution to form sodium nitrate, sodium sulfate, calcium nitrate, calcium sulfate, ammonium nitrate, ammonium sulfate And the like.

At this time, the chemical reaction in the wet scrubber 40 is represented by the following chemical formula 2.

(2)

2-1) NaOH + HNO _{2 -} > NaNO ₂ + H ₂ O

_{2-2) NaOH + HNO 3 → NaNO} 3 + H 2 O

2-3) NaOH + SO _{2 -} > NaSO ₃ + H ₂ O

That is, the generated nitrogen oxide such as the reaction of nitrogen dioxide in the exhaust gas and an alkaline aqueous solution of nitrous acid to react with water (HNO ₂₎ and nitric acid (HNO _3), and nitrous acid (HNO ₂₎ and nitric acid (HNO _3), and sulfur oxides are It is converted into various salts such as sodium nitrate, sodium sulfate, calcium nitrate, calcium sulfate, ammonium nitrate, and ammonium sulfate by reaction with an alkali solution to be removed.

The alkaline aqueous solution supply unit 50 is supplied with the aqueous alkaline solution from the circulation pump 55 contained in the alkaline aqueous solution storage unit 43 and is injected into the gas-liquid reaction unit 41 through the injection nozzle 53, The aqueous alkaline solution sprayed on the inner upper side of the reaction part 41 comes into contact with the rising exhaust gas to remove it while reacting with the nitrogen oxides and the sulfur oxides. Thereafter, the remaining alkali aqueous solution and the generated water (H ₂ O) used in the reaction with the reaction product are dropped and stored in the lower alkaline aqueous solution storage portion 43, and are reused again through the circulation pump 55.

As the aqueous alkaline solution to be stored in the alkaline aqueous solution storage part 43, an aqueous solution such as sodium hydroxide, calcium carbonate, calcium hydroxide, ammonia water and the like may be used.

In such a configuration, the alkali aqueous solution stored in the alkaline aqueous solution storage portion 43 gradually decreases in concentration due to the action of gas-liquid separation.

Thus, the alkaline drug supply unit 60 is configured to prevent the concentration of the alkaline aqueous solution from lowering.

The alkali chemical supply unit 60 is for maintaining the pH of the alkali aqueous solution suitable for removal of nitrogen oxides and sulfur oxides contained in the exhaust gas to an appropriate level and includes an alkaline chemical storage tank 61 and a chemical supply pump 63 And a pH detector for detecting the pH of the alkali solution contained in the alkali aqueous solution storage part 43 according to the design conditions.

The alkaline chemical storage tank 61 stores alkaline chemicals in a solution state such as sodium hydroxide, calcium carbonate, calcium hydroxide and ammonia water.

When the pH value of the alkaline aqueous solution storage portion 43 detected by the pH detector not shown in the figure is detected to be equal to or lower than the set value, the chemical supply pump 63 is driven so that the alkaline chemical stored in the alkali chemical storage tank 61 Is supplied to the alkaline aqueous solution storage portion (43).

At this time, in the present invention, the appropriate level of the pH of the alkaline aqueous solution stored in the alkaline aqueous solution storage portion 43 may be maintained at about 7 to 9.

Here, water generated by the gas-liquid reaction and alkali chemicals supplied from the alkali chemical supply unit 60 are introduced into the alkali aqueous solution storage unit 43. Thus, an agitator 70 for agitating the alkali aqueous solution remaining in the alkaline aqueous solution storage portion 43, the supplied alkaline chemicals and water evenly may be provided.

The stirrer 70 may include a motor and an impeller, and the motor may be configured to be capable of rotating in the normal or reverse direction according to design conditions. That is, by using a motor capable of normal / reverse rotation, the impeller can be driven by normal rotation and reverse rotation so that the remaining alkali aqueous solution, the supplied aqueous alkali solution, and water are stirred and mixed evenly.

The agitator 70 may be configured to operate at a different driving speed from a point of time when the alkali chemical supply unit 60 is driven and a non-driving point.

For example, in a typical gas-liquid reaction, water falling from the upper portion uniformly falls into the alkaline aqueous solution storage portion 43, so that the driving speed of the agitator 70 is lower than the alkaline aqueous solution contained in the alkaline aqueous solution storage portion 43 The driving speed of the agitator 70 at the time when the alkali chemical supply unit 60 is driven is controlled not only by the water containing the alkali aqueous solution and the water dropped, And may be configured to control the rotation speed to such an extent that the medicine can be stirred. That is, the driving speed of the agitator 70 may be configured to be relatively higher at a point of time when the alkali chemical supplying unit 60 is driven than when the alkali chemical supplying unit 60 is not driven.

Hereinafter, the operation of the present invention will be described.

In the case where the nitrogen oxides and sulfur oxides in the exhaust gas generated by the combustion of the fossil fuel in various power plants or steel mills are effectively treated and discharged by using the nitrogen oxide and sulfur oxide removal equipment 1 of the exhaust gas according to the present invention Gas ozone (O ₃ ) as an oxidant is supplied from the ozone generator 20 to the exhaust gas, which is fed through the duct 10, as shown in FIG. Next, the exhaust gas mixed with the ozone is allowed to pass through the oxidation catalyst 30 provided on the duct 10, and the reaction rate is accelerated by the catalyst material such as vanadium in the course of passing through the pores of the oxidation catalyst 30, Nitrogen monoxide (NO) and ozone in the exhaust gas react with each other to generate nitrogen dioxide (NO ₂ ).

The exhaust gas that has passed through the oxidation catalyst 30 flows into the lower portion of the lower portion of the gas-liquid reaction portion 41 of the wet scrubber 40, and the gas-liquid reaction portion 41, And uniformly diffuses and rises in the reaction part 41.

As the exhaust gas raised in the gas-liquid reaction part 41 is maximized in gas-liquid contact with the aqueous alkaline solution injected from the injection nozzle 53 provided inside the gas-liquid reaction part 41, the nitrogen oxide and sulfuric acid contained in the exhaust gas The exhaust gas having the nitrogen oxide and the sulfur oxide removed therefrom is sucked and discharged by a discharge fan 45 connected to the upper portion of the wet scrubber 40.

The remaining alkali aqueous solution used for the reaction with the nitrogen oxide of the exhaust gas and the salt generated by the reaction with the sulfur oxide in the gas-liquid reaction part 41 falls into the lower alkaline aqueous solution storage part 43 and is stored.

At this time, the pH stored in the alkaline aqueous solution storage part 43 is detected. When the pH is lower than the set pH, the alkaline drug supply part 60 is driven to supply the alkaline solution to the alkaline aqueous solution storage part 43, And the pH stored in the storage unit 43 is maintained at an appropriate level.

According to the present invention, ozone is supplied to the exhaust gas and is allowed to pass through the oxidation catalyst, thereby promoting the reaction between the nitrogen monoxide in the exhaust gas and ozone, which is the oxidizing agent, so that the nitrogen dioxide can be generated in a short time. There is an advantage that the nitrogen oxide and sulfur oxide contained in the exhaust gas can be simultaneously treated promptly by contact with the alkali aqueous solution in the gas-liquid reaction part of the wet scrubber.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1. Simultaneous removal of nitrogen oxides and sulfur oxides
10: duct 20: ozone supply part
21: ozone generator 23: chlorate ion storage tank
30: oxidation catalyst 40: wet scrubber
41: gas-liquid reaction part 43: alkaline aqueous solution storage part
45: Exhaust fan 47: Perforated plate
50: Alkaline aqueous solution supply part 51:
53: injection nozzle 55: circulation pump
60: Alkaline drug supply unit 61: Alkaline drug storage tank
63: chemical feed pump 70: stirrer

Claims (3)

An ozone supply part (20) for supplying ozone to the exhaust gas conveyed along the duct (10);
An oxidation catalyst 30 for promoting the reaction of nitrogen monoxide and ozone in the exhaust gas with the passage of exhaust gas mixed with ozone to produce nitrogen dioxide;
And an alkaline aqueous solution storage part 43 is provided in the lower part so as to be vertically communicated with each other and an exhaust gas passing through the oxidation catalyst 30 is introduced into the lower part of the gas-liquid reaction part 41 A wet scrubber (40) for removing nitrogen oxides and sulfur oxides contained in the exhaust gas by contacting with an alkaline aqueous solution into which the introduced exhaust gas is injected;
An alkali aqueous solution supply part 50 for spraying an aqueous alkaline solution to the gas-liquid reaction part 41;
An alkaline drug supply unit 60 for supplying the alkaline drug to the alkaline aqueous solution storage unit 43; And
An agitator 70 for agitating the alkaline aqueous solution stored in the alkaline aqueous solution storage portion 43, the alkaline solution supplied from the alkaline aqueous solution supply portion 50, and water;
And,
The ozone supply unit 20 includes:
An ozone generator 21; And
A chlorinated ionized water storage tank 23 storing chlorate ions composed of one selected from sodium hypochlorite (NaClO), sodium hydrogencarbonate (NaClO ₂ ), and sodium chloride (NaClO ₃ );
Wherein the ozone generated by the ozone generator 21 is supplied through the chlorine ion water stored in the chlorine ionized water storage tank 23,
The oxidation catalyst (30)
Wherein a catalyst material selected from the group consisting of vanadium, zeolite, platinum and palladium is coated on the inner peripheral surface of the pores,
In the wet scrubber 40,
A perforated plate 47 provided with a plurality of through holes in the circular plate to diffuse the exhaust gas introduced into the gas-liquid reaction part 41 and induce the exhaust gas upward;
Respectively,
The alkali aqueous solution supply unit (50)
A spray tube (51) installed in the gas-liquid reaction part (41) in a multi-stage manner so as to be spaced apart from each other by a predetermined distance in the vertical direction;
A spray nozzle 53 installed in the zigzag direction on the top, bottom and side surfaces of the spray tube 51 for spraying the sprayed alkali solution in a mist form; And
A circulation pump 55 for pumping the alkaline aqueous solution contained in the alkaline aqueous solution storage part 43 and supplying it to the spraying tube 51;
And,
Wherein the driving speed of the agitator (70) is configured to be relatively higher when the alkali chemical supplying unit (60) is driven than when the alkali chemical supplying unit (60) is not driven.
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