KR101121912B1 - Device for removing sulfur oxide in flue gas - Google Patents

Abstract

In the present invention, in the sulfur oxide treatment apparatus of the flue gas comprising an absorption tower for removing the sulfur oxide contained in the flue gas introduced into the interior, the absorption tower is an inlet pipe for introducing the leachate of the slag treatment plant in the furnace, and A discharge pipe for discharging the leachate to the outside, the sulfur oxide contained in the exhaust gas is removed by the reaction of the leachate and the exhaust gas introduced through the inlet pipe, the leachate is discharged through the discharge pipe.

According to the present invention, in the treatment of flue gas containing sulfur oxides, the leachate of reducing slag, which is a by-product generated in the steelmaking process, is recycled and used in the flue gas using a reactant such as limestone, caustic soda, magnesium hydroxide, and activated carbon. Compared to the removal of sulfur oxides, the cost is significantly reduced. In addition, by precipitating gypsum (CaSO ₄ ~ 2H ₂ O) components in the leachate in the sedimentation tank, it is possible to recycle the supernatant in the leachate through the sedimentation tank as well as to additionally obtain gypsum.

Furnace Slag Treatment Plant, Leachate

Description

Device for removing sulfur oxide in flue gas

The present invention relates to an apparatus for treating sulfur oxides in flue gas, and more particularly, to an apparatus for treating sulfur oxides in flue gas for removing sulfur oxides (SO _x ) by using leachate of reducing slag as a by-product generated in an electric furnace steelmaking process. will be.

Exhaust gases generated from factories and incinerators contain various pollutants such as sulfur oxides (SO _x ) and nitrous oxides (NO _x ), and the amount of pollutants contained in the exhaust gases is increasing due to industrial development.

The sulfur oxides contained in the flue gas are not only the main cause of acid rain in addition to the nitric oxide, but also the major air pollutants that cause optical smog.

As a method of removing the sulfur oxide (SO _x ), there is a method of injecting a reactant such as caustic soda method, magnesium hydroxide method, lime method, activated carbon method.

Lime method is a method to remove the sulfur oxide contained in the exhaust gas in the form of hydroxide, lime method has the advantage of low cost in terms of cost, but it is mainly used in large facilities because of low efficiency and problems such as scale generation.

In addition, caustic soda method is a method of removing sulfur oxides from flue gas by reacting flue gas with lime water or caustic soda solution. Caustic soda method is a relatively simple and efficient technique, but it uses strong alkali caustic soda (NaOH). Corrosion problems and disposal of strong alkali by-products occur.

In the case of magnesium hydroxide method, it is harmless to the human body and has high desulfurization efficiency, but requires sludge injection equipment, and it is necessary to control oxidizing conditions so that problems such as scale do not occur. Activated carbon method has high efficiency but high operating cost It is difficult to apply to the actual industrial site because it requires.

The present invention is to solve the conventional problems as described above, the present invention in the treatment of sulfur oxides contained in the flue-gas sulfuric acid of the flue gas that can improve the treatment efficiency of sulfur oxides at low cost while replacing the existing reactants The object is to provide a cargo handling device.

According to a feature of the present invention for achieving the above object, the present invention is a sulfur oxide treatment apparatus of the exhaust gas comprising an absorption tower for removing the sulfur oxide contained in the exhaust gas flowing into the absorption tower, A sulfur oxide contained in the exhaust gas by a reaction between the leachate introduced through the inlet pipe and the exhaust gas; This is removed, and the leachate is discharged through the discharge pipe.

In addition, the leachate discharged through the discharge pipe may further include a settling tank to precipitate the gypsum (CaSO ₄ ~ 2H ₂ O) component in the leachate.

In addition, the leaching water of the sedimentation tank may further include a connection pipe for discharging to the slag treatment plant.

In addition, the absorption tower, at least one spray nozzle for spraying the leachate introduced through the inlet pipe to the exhaust gas therein, and the filling material disposed below the spray nozzle to improve the contact efficiency of the exhaust gas and the leachate It may further include.

In addition, the absorption tower is composed of a packed type, a spray type, a perpolated plate type, an impingement type, a bubble type, and a venturi type. It may be one selected from the group.

The leachate treatment tank may further include a leachate treatment tank provided between the furnace slag treatment plant and the absorption tower, in which fine slag reduction slag or impurities are included in the leachate discharged from the furnace slag treatment plant.

The apparatus may further include a selective catalytic denitrification apparatus for reducing nitric oxide contained in exhaust gas passing through the absorption tower.

In the present invention, sulfuric acid contained in flue gas using a reactant such as limestone, caustic soda, magnesium hydroxide, activated carbon by recycling the leachate of reducing slag which is a by-product generated in the steelmaking process in the treatment of flue gas containing sulfur oxides. Compared to the method of removing the cargo, the cost is significantly reduced.

In addition, by precipitating gypsum (CaSO ₄ ~ 2H ₂ O) components in the leachate in the sedimentation tank, it is possible to recycle the supernatant in the leachate through the sedimentation tank as well as to additionally obtain gypsum.

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

1 is an overall configuration diagram of an apparatus for treating sulfur oxides in exhaust gas according to the present invention.

The sulfur oxide treatment apparatus 100 of the exhaust gas of the present invention includes an absorption tower 30 for removing sulfur oxides contained in the exhaust gas.

An electric furnace slag treatment plant 10 is provided to treat slag generated in an electric furnace process, and the industrial furnace slag treatment plant 10 uses industrial water to cool the hot slag and promote ripening. Large amounts of leachate are generated.

The leachate of the electric furnace slag treatment plant 10 contains a large amount of Ca constituents due to quicklime used in hot rolling mills, etc., and an example of the leachate components is shown in Table 1 below.

Item PH COD _CF SS Ca ²⁺ NH ₄ ⁺ Na ⁺ Cl ^- F ^- NO ₃ ^- density
(mg / L) 11.99 13.3 114.9 942.5 0.5 1,124 2,308 1.1 2.4

As shown in Table 1, the leachate of the electric furnace slag treatment plant 10 contains a large amount of Ca component, it is judged as a large amount of slaked lime component whose pH is close to 12.

The leachate has a high content of Ca that can be used to remove sulfur oxides, and thus is suitable for replacing existing reactants, for example, limestone, caustic soda, magnesium hydroxide, and the like. To remove the sulfur oxides contained in the flue gas.

Leachate of the furnace slag treatment plant 10 is introduced into the absorption tower (30). Here, the leachate treatment tank 20 may be further provided between the furnace slag treatment plant 10 and the absorption tower 30.

In the leachate treatment tank 20, fine particles of reduced slag or impurities contained in the leachate discharged from the slag treatment plant 10 are precipitated.

Absorption tower 30 is to remove the sulfur oxides contained in the exhaust gas flowing into the inside, the inlet pipe 25 for introducing the leachate of the electric furnace slag treatment plant 10 and the discharge to discharge the leachate to the outside A pipe 45.

The inflow pipe 25 connects the leachate treatment tank 20 and the absorption tower 30, and guides and inflows the leachate via the electric furnace slag treatment plant 10 and the leachate treatment tank 20 to the absorption tower 30. Let's do it.

A frame member 31 for guiding the flow of leachate flowing through the inlet pipe 25 is disposed above the absorption tower 30, and the leachate introduced into the frame member 31 can be evenly sprayed with exhaust gas. At least one spray nozzle 32 is installed.

In the absorption tower 30, a filler 33 is disposed below the spray nozzle 32 to enhance the contact efficiency between the exhaust gas and the leachate.

The filler 33 may be made of HDPE (High Density Polyethylene), but is not limited thereto.

The absorption tower 30 is a packed tower absorption tower, the absorption tower of the present invention is not limited to the packed absorption tower, spray type, perpolated plate type, Impingement type, Bubble type, Venturi type are also applicable, and combinations thereof are also possible.

An optional catalyst denitrification apparatus 50 for reducing nitric oxide (NO _x ) contained in the exhaust gas passing through the absorption tower 30 may be disposed at the rear end of the absorption tower 30.

This is a post-treatment facility for the exhaust gas that has passed through the absorption tower 30. Nitrogen oxide (NO _x ) contained in the exhaust gas is converted into nitrogen (N ₂ ) and water (H ₂ O) using a catalyst such as a vanadium-based catalyst. Reduce.

The selective catalytic denitrification apparatus 50 applies Selective Catalytic Reduction (SCR) or coke selective catalytic reduction (CSCR), and the SCR or CSCR process is a catalyst. By using it, the treatment efficiency can be increased up to 90%, and there is an advantage that it can be processed at a low temperature of 250 ~ 350 ℃.

On the other hand, the leachate discharged through the discharge pipe 45 is recovered to the settling tank (40).

The settling tank 40 is connected to the absorption tower 30 through the discharge pipe 45, the gypsum (CaSO ₄ ~ 2H ₂ O) components in the leachate discharged through the discharge pipe 45 is precipitated, the settling tank 40 The leached water recovered in the above becomes the supernatant from which the Ca component is removed.

Leachate of the settling tank 40 is connected to the furnace slag treatment plant 10 through the connecting pipe 15, the leaching water of the supernatant in the settling tank 40 through the connecting pipe 15 back to the furnace slag treatment plant 10 Supplied.

Hereinafter, the operation of the sulfur oxide treatment apparatus for exhaust gas of the present invention will be described.

The absorption tower 30 sprays the leachate into the exhaust gas evenly through the spray nozzle 32 to remove the sulfur oxides contained in the exhaust gas in order to contact the sulfur oxide contained in the exhaust gas introduced into the inside.

The reaction of the leachate containing a large amount of Ca and sulfur oxides, that is, the desulfurization reaction, is shown in Scheme 1 below.

Ca + SO _x + H ₂ O = CaSO _{4 ?} 2H ₂

Referring to Scheme 1, sulfur oxide (SO _x ) contained in the exhaust gas is a gypsum (CaSO ₄ ~ 2H ₂ O) component.

The leachate sprayed from the spray nozzle 32 reacts with the sulfur oxides of the exhaust gas, and then flows into the settling tank 40 through the discharge pipe 45 of the absorption tower 30, and the gypsum in the leachate flowing into the settling tank 40. (CaSO ₄ -2H ₂ O) component is precipitated.

Therefore, by precipitating the gypsum (CaSO ₄ -2H ₂ O) component in the leachate in the precipitation tank 40, gypsum can be obtained incidentally.

The leaching water recovered in the settling tank 40 is a supernatant water by Ca component is precipitated and removed as a gypsum (CaSO ₄ ~ 2H ₂ O) component, the leaching water of the supernatant is an electric furnace slag treatment plant (10) through a connecting pipe (15) Are recycled and recycled.

Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely exemplary, and various modifications and equivalent other embodiments are possible, as well as those skilled in the art. The scope of technical protection should be defined by the technical spirit of the appended claims.

1 is an overall configuration diagram of an apparatus for treating sulfur oxides in exhaust gas according to the present invention.

<Description of the symbols for the main parts of the drawings>

10: electric furnace slag treatment plant 20: leachate treatment tank

30: absorption tower 31: frame member

32: spray nozzle 33: filling material

40: sedimentation tank 50: selective catalyst denitrification apparatus

Claims (7)

In the sulfur oxide treatment apparatus of the exhaust gas comprising an absorption tower for removing the sulfur oxides contained in the exhaust gas flowing into the interior, The absorption tower includes an inflow pipe for introducing the leachate of the slag treatment plant into the inside, and a discharge pipe for discharging the leachate to the outside, Sulfur oxides contained in the exhaust gas are removed by the reaction of the leachate and the exhaust gas introduced through the inlet pipe, and the leachate is discharged through the discharge pipe. The method according to claim 1, And a sedimentation tank for recovering the leachate discharged through the discharge pipe and precipitating gypsum (CaSO ₄ -2H ₂ O) component in the leachate. The method according to claim 2, And a connection pipe for discharging the leachate of the sedimentation tank to the electric furnace slag treatment plant. The method according to claim 1, The absorption tower, at least one spray nozzle for spraying the leachate introduced through the inlet pipe to the exhaust gas therein; The sulfur oxide treatment apparatus of the exhaust gas further comprises a filler disposed below the spray nozzle to improve the contact efficiency of the exhaust gas and the leachate. The method according to claim 1, The absorption tower is selected from the group consisting of a packed tower, a spray type, a perpolated plate type, an impingement type, a bubble type, and a venturi type. Sulfur oxide treatment apparatus for exhaust gas, characterized in that the selected one. The method according to claim 1, The effluent treatment tank further comprises a leachate treatment tank provided between the furnace slag treatment plant and the absorption tower to deposit fine particles of reduced slag or impurities contained in the leachate discharged from the furnace slag treatment plant. Sulfur oxide treatment equipment. The method according to claim 1, The apparatus for treating sulfur oxides of exhaust gases further comprising a selective catalytic denitrification apparatus for reducing nitric oxide contained in the exhaust gas passing through the absorption tower.

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