KR101800517B1 - Wet-type Apparatus and Method for Removing Harmful Substance from Exhaust Gas - Google Patents

Abstract

In the present invention, in order to carry out the denitrification process and the desulfurization process wet with the nitrogen oxide and the sulfur oxide contained in the exhaust gas, a primary treatment process is performed in which the exhaust gas is subjected to a plasma reaction to generate nitrogen dioxide from the nitrogen monoxide contained in the exhaust gas And a secondary reaction step of performing a secondary treatment step in which a denitration step and a desulfurization step are performed in parallel with the exhaust gas discharged from the plasma reaction part, And an additive supply unit for supplying an additive in the form of an aqueous solution or a slurry to the reaction unit. The present invention also relates to a wet removal apparatus and a wet removal method for an exhaust gas.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a wet-type wet-removing apparatus and a wet-

The present invention relates to a device for removing harmful substances from a flue gas and a wet removal method for removing harmful substances such as sulfur oxides and nitrogen oxides from the flue gas.

Generally, in a workplace such as a steel mill, a power plant, or an incinerator, an exhaust gas containing harmful substances is generated. For example, the exhaust gas contains harmful substances such as sulfur oxides (SOx) and nitrogen oxides (NOx). These harmful substances cause environmental problems such as smog, acid rain, global warming and ozone layer destruction. In recent years, in order to solve environmental problems caused by harmful substances contained in flue gas, the emission standard for harmful substances has been strictly strengthened, and technologies for removing pollutants from the exhaust gas discharged from the business sites have been actively developed.

To remove sulfur oxides and nitrogen oxides contained in the flue-gases, prior art flue-gas treatment systems include desulfurization and denitrification plants.

The desulfurization facility performs a desulfurization process to remove sulfur oxides from the exhaust gas. The most typical desulfurization equipment is FGD (Flue Gas Desulfurization), which is mainly applied by wet process. The wet method is a method in which water or an alkaline solution is used as an absorbent to absorb soluble contaminants such as sulfur oxides (SOx) in an exhaust gas, and reacted with an alkaline component. The technology has the advantage that the removal efficiency of sulfur oxides is higher than 90%, but there is a restriction that further denitrification equipment is necessary because denitrification is not performed.

The denitration facility performs a denitration process for removing nitrogen oxides from the exhaust gas. The denitrification facility includes Selective Catalytic Reduction (SCR) or Selective Non-Catalytic Reduction (SNCR). SCR removes nitrogen oxides from the exhaust gas by injecting ammonia, a reducing agent, into the V ₂ O ₅ / TiO ₂ catalyst and converting it into harmless nitrogen gas by reacting with nitrogen oxides. However, SCR requires a high temperature (300 ° C) for the catalytic reaction, and there is a problem that the operating cost is increased because it uses an expensive catalyst. SNCR, on the other hand, removes nitrogen oxides by injecting a reducing agent directly into the hot exhaust gas without a catalyst. The SNCR does not use a catalyst, so it has a low operating cost for the catalyst, but the reaction temperature (850 ~ 1,050 ℃) must be kept high and the removal efficiency of nitrogen oxide is lower than 60%.

The conventional flue gas treating system is divided into the desulfurization facility and the denitrification facility to remove sulfur oxides and nitrogen oxides from the flue gas. As the desulfurization facility and the denitrification facility are respectively installed and operated as described above, the conventional technology has increased operational inefficiency. For example, in the case of denitrification, a high temperature is required, so that the process goes through a temperature increase. In the case of desulfurization, the flue gas is operated at a low temperature due to a wet process characteristic. Since the exhaust gas conditions required for the efficient operation of denitrification and desulfurization are different from each other and independent technologies are applied, there are cases where the respective operating conditions adversely affect the mutual removal efficiency.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above problems, and it is an object of the present invention to provide a device for removing harmful substances from a flue gas and a wet removal method for removing sulfur oxide and nitrogen oxides from the flue gas simultaneously.

In order to solve the above problems, the present invention includes the following configuration.

In order to perform the denitrification process and the desulfurization process in combination with the nitrogen oxides and sulfur oxides contained in the exhaust gas, the exhaust gas is subjected to a plasma reaction to remove the nitrogen monoxide contained in the exhaust gas from the nitrogen monoxide A plasma reaction unit for performing a primary treatment process for generating nitrogen dioxide; A wet reaction unit connected to the plasma reaction unit and performing a secondary treatment process in which the exhaust gas discharged from the plasma reaction unit is subjected to a denitration process and a desulfurization process; And an additive supply unit for supplying an aqueous solution or an additive in a slurry state to the wet reaction unit such that the secondary treatment process is performed in a wet manner.

A method for removing harmful substances from an exhaust gas according to the present invention comprises: plasma-reacting an exhaust gas to perform a primary treatment process for producing nitrogen dioxide from nitrogen monoxide contained in an exhaust gas; Supplying an additive in an aqueous solution state or a slurry state to an exhaust gas passed through the primary treatment step; And performing a secondary treatment process in which a denitration process and a desulfurization process are performed in parallel with the exhaust gas that has undergone the primary treatment process using the additive in a wet process.

According to the present invention, the following effects can be achieved.

The present invention is implemented to perform a denitration process and a desulfurization process through a single wet processing facility, thereby reducing the size of the installation area, thereby alleviating the restriction on the site area and constructing a treatment facility for harmful substances Can reduce the construction cost.

Since the present invention is implemented to perform the denitrification process in a wet manner, it is possible to construct a desulfurization desulfurization facility through remodeling of the existing desulfurization desulfurization facility, so that the existing desulfurization desulfurization facility can be reused, Can be reduced.

The present invention can be carried out in a wet manner by performing the denitration process and the desulfurization process simultaneously at the exhaust gas temperature and below, thereby omitting the temperature raising process and the temperature raising device, so that the construction cost can be further reduced, Because there is no energy savings, operating costs can be reduced.

Since the present invention converts nitrogen oxide into nitrogen dioxide having high solubility, high denitrification efficiency can be achieved even if the denitration process is performed in combination with the desulfurization process and wet.

The present invention can be implemented to perform both the denitrification process and the desulfurization process in a wet manner under the same operating conditions, thereby reducing inefficiency and side effects that are caused when different operating conditions are applied to each of the denitrification process and the desulfurization process.

1 is a schematic view of a device for removing harmful substances from a waste gas according to the present invention
2 is a block diagram of an apparatus for removing harmful substances from a waste gas according to the present invention
3 is a schematic flowchart of a method for removing harmful substances from a flue gas according to the present invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a device for removing harmful substances from a flue gas according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of an apparatus for removing harmful substances from a flue gas according to the present invention, and FIG. 2 is a block diagram of an apparatus for removing harmful substances from a flue gas according to the present invention.

1 and 2, an apparatus 1 for removing harmful substances from an exhaust gas according to the present invention is for removing harmful substances from an exhaust gas discharged from an exhaust gas generating source 10. The exhaust gas generator 10 may be a steel mill, a power plant, an incinerator, or the like. For example, the exhaust gas generating source 10 may be a sintering facility for performing a sintering process for processing iron ore into a massive form which is easy to be charged into a blast furnace or the like in a steelworks. The exhaust gas discharged from the exhaust gas generator 10 contains nitrogen oxides (NOx) and sulfur oxides (SOx) as harmful substances.

The apparatus 1 for removing harmful substances from a flue gas according to the present invention performs a wet denitrification process and a desulfurization process on the nitrogen oxides and sulfur oxides contained in the flue gas to remove harmful substances from the flue gas, So that the removed flue gas is discharged to the atmosphere through the stack 20.

To this end, the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention comprises a plasma reactor 2 for carrying out a primary treatment process by plasma-reacting an exhaust gas, an additive supplier 3 for supplying an additive, And a wet reaction section (4) for performing a secondary treatment process on the exhaust gas discharged from the plasma reaction section (2) in a wet manner.

The plasma reactor ₂ performs a primary treatment process for generating nitrogen dioxide (NO ₂ ) from nitrogen monoxide (NO) contained in the exhaust gas. Accordingly, the plasma reactor 2 converts nitrogen monoxide, which is low in reactivity and solubility, which is difficult to wet process, to nitrogen dioxide which is relatively reactive and soluble and can be wet processed.

The additive supply part 3 supplies the additive in the form of an aqueous solution or a slurry to the wet reaction part 3. Thus, the additive supply unit 3 allows the denitrification process and the desulfurization process to be performed in the wet process in the secondary treatment process.

As described above, the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention converts nitric oxide, which is difficult to wet process, into nitrogen dioxide which can be subjected to wet treatment through the primary treatment process, And performing the denitrification process and the desulfurization process in parallel by wet process. Therefore, the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention can achieve the following operational effects.

Since the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention performs the denitrification process and the desulfurization process through a single wet processing facility, it is possible to reduce the size of the installation area, In addition, it can reduce the construction cost of constructing treatment facilities for hazardous substances.

Since the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention is implemented to perform the denitrification process in a wet manner, the denitrification process and the desulfurization process can be performed in parallel with the existing wet desulfurization facility It is possible to construct a facility to perform. Accordingly, the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention is capable of performing both of the denitrification process and the desulfurization process by reusing the existing wet desulfurization facility. Thereby further reducing the construction cost.

Since the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention is implemented to perform the denitrification process and the desulfurization process in a wet manner, the denitrification process and the desulfurization process can be performed simultaneously at an exhaust gas temperature or below. Accordingly, the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention does not require the temperature raising process and the temperature raising process which have been conventionally required in the denitrification process. Therefore, the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention not only reduces the construction cost, but also reduces the operating cost through energy saving because there is no fuel consumption for the temperature rise.

Since the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention converts nitrogen oxide into nitrogen dioxide having high solubility through the primary treatment process, the denitrification process is performed in parallel with the desulfurization process, Denitrification efficiency can be realized.

Since the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention can perform both the denitrification process and the desulfurization process in a wet manner under the same operation condition, different operating conditions are applied to each of the denitrification process and the desulfurization process It is possible to reduce the inefficiency and adverse effects that occur when applied.

Hereinafter, the plasma reaction unit 2, the additive supply unit 3, and the wet reaction unit 4 will be described in detail with reference to the accompanying drawings.

1 and 2, the plasma reactor 2 is installed between the exhaust gas generator 10 and the wet reactor 4. The exhaust gas discharged from the exhaust gas generating source 10 is supplied to the plasma reactor 2 and then supplied to the wet reactor 4 via the plasma reactor 2.

The plasma reactor 2 generates a plasma by discharging the exhaust gas. Accordingly, the plasma reaction unit 2 performs the primary treatment process on the nitrogen oxide contained in the exhaust gas by plasma-reacting the exhaust gas. Through the primary treatment process, the plasma reactor 2 can convert nitrogen monoxide contained in the exhaust gas into nitrogen dioxide by generating nitrogen dioxide from the nitrogen monoxide contained in the exhaust gas.

Therefore, the plasma reactor 2 can convert nitrogen monoxide, which is low in reactivity and solubility so that it is difficult to wet process, into nitrogen dioxide which is relatively reactive and soluble and can be subjected to wet treatment, .

For example, through the primary treatment process, the nitrogen monoxide contained in the exhaust gas can be converted into nitrogen dioxide according to the following reaction formula (1).

[Reaction Scheme 1]

[O] in the above reaction scheme 1 means various kinds of oxides. For example, [O] may be oxygen atoms (O), ozone (O ₃ ), etc. formed as the exhaust gas is discharged to a plasma state.

In addition to the conversion of nitrogen monoxide to nitrogen dioxide in the primary treatment step, the plasma reactor 2 may be subjected to a plasma reaction so that nitric acid (HNO ₃ ) is produced from nitrogen dioxide. That is, the primary treatment step may include a conversion reaction for converting nitrogen monoxide to nitrogen dioxide, and a nitric acid reaction for generating nitric acid from a part of nitrogen dioxide. For example, in the primary treatment step, the nitric acid reaction can be carried out according to the following reaction formula (2).

[Reaction Scheme 2]

As shown in Reaction Scheme 2, a portion of the nitrogen dioxide may be generated as nitric acid by reacting with a hydroxyl group (OH). The hydroxyl group may be generated from the exhaust gas and water molecules (H ₂ O) contained in the air existing inside the plasma reactor (2).

The plasma reactor 2 may include a plasma chamber 21, and a conditioning unit 22.

In the plasma chamber 21, the primary treatment process is performed. The plasma chamber 21 may include a discharge electrode or the like for discharging the exhaust gas using electric power supplied from the control unit 22. [ The plasma chamber 21 may include a perforated plate installed on the inlet side and the outlet side so that the exhaust gas can be uniformly introduced and discharged. The plasma reactor 2 may be a low-temperature plasma reactor.

The plasma chamber 21 may be connected to the exhaust gas source 10 through a connecting duct 30. One side of the connecting duct 30 is connected to the exhaust gas generating source 10 and the other side of the connecting duct 30 is connected to the plasma chamber 21. The exhaust gas is discharged from the exhaust gas generating source 10 and then supplied to the plasma chamber 21 through the connecting duct 30. A blowing fan (not shown) may be coupled to the connecting duct 30 to move the exhaust gas. The blowing fan discharges the exhaust gas from the exhaust gas generating source 10 using a suction force and a wind force to cause the exhaust gas discharged from the exhaust gas generating source 10 to flow from the plasma reactor 2 to the wet reactor 4 Can be moved.

The conditioning unit 22 is coupled to the plasma chamber 21. The regulating unit 22 can generate plasma inside the plasma chamber 21 by supplying electric power to the exhaust gas located inside the plasma chamber 21. The control unit 22 can adjust the energy density of the electric power supplied to the plasma chamber 21 by adjusting the amount of electric power supplied to the plasma chamber 21. Accordingly, the control unit 22 can control the conversion ratio at which nitrogen dioxide is produced from nitrogen monoxide in the primary treatment process. By increasing the amount of power supplied to the plasma chamber 21, the control unit 22 can increase the conversion ratio to nitrogen dioxide in the primary treatment process. The control unit 22 can adjust the energy density of power supplied to the plasma chamber 21 according to process conditions such as a conversion ratio related to denitration efficiency, a power consumption related to an operation cost, and operating conditions.

The regulating unit 22 may include a power supply (not shown) and a pulse generator (not shown). Electricity generated in the power supply device is applied to the pulse generator, and a high voltage pulse generated in the pulse generator is applied to the plasma chamber, so that plasma can be generated in the plasma chamber. The high voltage pulse may be supplied to the plasma chamber 21 through a copper pipe.

1 and 2, the additive supply part 3 is for supplying the additive to the wet reacting part 4. As shown in FIG. The additive supply part (3) supplies an additive in the form of an aqueous solution or a slurry to the wet reaction part (4). Accordingly, the additive supplier 3 causes the denitrification process and the desulfurization process to be performed in a wet manner in the secondary treatment process.

The additive supply part 3 may be connected to the wet reaction part 4 through a connection pipe 40. One side of the connection pipe 40 is connected to the additive supply part 3 and the other side is connected to the wet reaction part 4. The additive supply unit 3 can supply the additive into the wet reaction unit 4 through the connection pipe 40.

The additive supplier 3 can supply the desulfurizing additive to the wet reactor 4. The additive for desulfurization reacts with sulfur dioxide (SO ₂ ) contained in the exhaust gas to generate an alkali salt, thereby removing sulfur oxides from the exhaust gas. For example, the additive supply unit (3), magnesium hydroxide (Mg (OH) _2), sodium hydroxide (NaOH), a desulfurizing additive for containing one of a calcium carbonate (CaCO _3), and calcium hydroxide (Ca (OH) ₂₎ is To the wet reaction unit (4).

The additive supplier 3 can supply the denitration additive to the wet reactor 4. The denitration additive reacts with the nitrogen dioxide generated through the primary treatment step to generate nitrogen (N ₂ ), thereby removing nitrogen oxides from the exhaust gas. For example, the additive supply part 3 can supply a denitration additive containing sodium sulfide (Na ₂ S) or sodium sulfite (Na ₂ SO ₃ ) to the wet reaction part 4.

The additive supplier 3 can supply both the desulfurization additive and the denitration additive to the wet reactor 4. In this case, the additive supplying portion 3 can supply the desulfurizing additive and the denitrating additive to the wet reacting portion 4 in an aqueous solution state or a slurry state. Accordingly, the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention can be performed in parallel with the denitrification process and the desulfurization process in a wet manner.

The additive supply unit 3 may include a storage chamber 31, and a stirring unit 32.

The storage chamber 31 is for storing the denitration additive and the desulfurization additive. The storage chamber 31 may store the denitration additive and the desulfurization additive in an aqueous solution state or a slurry state. The storage chamber 31 may be connected to the wet reaction unit 4 through the connection pipe 40.

The stirring unit (32) is installed in the storage chamber (31). The agitating unit 32 may stir the denitration additive and the desulfurizing additive stored in the storage chamber 31 so that the wet additive is supplied to the wet reacting unit 4. The agitation unit 32 may agitate the denitration additive and the desulfurization additive by rotating a stirring blade installed in the reservoir chamber 31.

Although not shown, the additive supply unit 3 may include a plurality of the storage chambers 31. In this case, the additive supply part 3 may include a first storage chamber for storing the denitration additive, and a second storage chamber for storing the desulfurization additive. The denitration additive and the desulfurization additive may be separately supplied to the wet reaction unit 4. [ The denitration additive and the desulfurization additive may be supplied to the wet reaction unit 4 in a mixed state after being discharged from the first storage chamber and the second storage chamber, respectively.

Referring to FIGS. 1 and 2, the wet reaction unit 4 is connected to the plasma reaction unit 3. The wet reaction unit 4 may be connected to the plasma reaction unit 3 through a reaction duct 50. One side of the reaction duct 50 may be connected to the plasma chamber 21 and the other side thereof may be connected to the wet reaction unit 4. The exhaust gas discharged from the plasma reaction unit 3 may be supplied to the wet reaction unit 4 through the reaction duct 50.

The wet reacting unit 4 performs a secondary treatment process in which the exhaust gas discharged from the plasma reactor 3 is subjected to the secondary denitrification process and the desulfurization process in a wet process. The wet reacting section 4 is configured to wet the nitrogen dioxide produced through the primary treatment process and the sulfur dioxide contained in the exhaust gas using the additive in the aqueous solution state or the slurry state supplied from the additive supply section 3, By performing the treatment process, harmful substances can be removed from the flue gas.

When the denitration additive containing sodium sulfide is supplied from the additive supplier 3, the wet reactor 4 may perform the denitrification process according to the following reaction formula (3). In this case, the additive supplier 3 may supply only the sodium sulfide as the denitration additive to the wet reactor 4.

[Reaction Scheme 3]

When the denitration additive containing sodium sulfite is supplied from the additive supplier 3, the wet reactor 4 may perform the denitrification process according to the following reaction formula (4). In this case, the additive supplier 3 may supply only the sodium sulfite to the wet reactor 4 as an additive for denitration.

[Reaction Scheme 4]

As shown in Reaction Schemes 3 and 4, the nitrogen dioxide produced through the primary treatment may be reacted with a denitration additive containing sodium sulfide or sodium sulfite to form nitrogen and sodium sulfate (Na ₂ SO ₄ ) have. Accordingly, the nitrogen dioxide is purified while being converted into nitrogen gas, and then discharged from the wet reaction unit 4 and discharged through the stack 20. The sodium salt produced in this process remains in the wet reaction part 4 in the form of an aqueous solution and may be discharged to a wastewater treatment facility (not shown) and water treated.

When the additive for desulfurization containing calcium hydroxide is supplied from the additive supplier 3, the wet reactor 4 may perform the desulfurization process according to the following reaction formulas 5 and 6. In this case, the additive supply part 3 may be supplied to the wet reaction part 4 using only calcium hydroxide as an additive for desulfurization.

[Reaction Scheme 5]

[Reaction Scheme 6]

As shown in Reaction Scheme 5 and Reaction Scheme 6, sulfur dioxide in the exhaust gas discharged from the plasma reactor 2 reacts with a desulfurizing additive containing calcium hydroxide to form calcium salts such as calcium sulfate (CaSO ₄ ) and calcium sulfite (CaSO ₃ ) Lt; / RTI > Accordingly, the sulfur dioxide is removed from the flue gas while being converted to calcium salt. The sulfur dioxide-free flue gas is discharged from the wet reaction unit 4 and discharged through the stack 20. The calcium salt produced in this process may remain in the wet reaction unit 4 in the form of an aqueous solution and may be discharged to the wastewater treatment facility and treated with water.

The wet reaction section 4 may include a wet reaction chamber 41, an inlet port 42, and a jetting mechanism 43.

In the wet reaction chamber 41, the secondary treatment process is performed. The wet reaction chamber 41 may be connected to the plasma reactor 2 through the reaction duct 50. The wet reaction chamber 41 may be connected to the additive supply unit 3 through the connection pipe 40.

The inlet 42 is formed in the wet reaction chamber 41 so that the exhaust gas discharged from the plasma reactor 2 is supplied to the inside of the wet reaction chamber 41. The inlet (42) may be connected to the reaction duct (50). The inlet (42) serves as a passageway for the flue gas.

The injection mechanism (43) is connected to the additive supply part (3). The injection mechanism 43 may be connected to the additive supply unit 3 through the connection pipe 40. The injection mechanism 43 can inject the additive supplied from the additive supply part 3 into the inside of the wet reaction chamber 41. Accordingly, in the wet reaction chamber 41, a secondary treatment process in which the denitration process and the desulfurization process are performed in parallel using the additive may be performed.

The injection mechanism 43 may be coupled to the wet reaction chamber 41 to be located at a higher position than the inlet 42. Accordingly, the injection mechanism 43 can inject the additive toward the rising exhaust gas flowing into the wet reaction chamber 41 through the inlet 42. Therefore, the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention increases the contact between the flue gas and the additive by using the characteristic that the flue gas rises and the additive in the aqueous solution state or the slurry state falls by gravity, The denitration efficiency for the denitration process and the desulfurization efficiency for the desulfurization process can be enhanced.

The injection mechanism 43 may include a plurality of nozzles for injecting the additive. The nozzles may be arranged to be spaced apart from each other so that the additive is uniformly injected into the exhaust gas flowing into the wet reaction chamber 41 and rising.

The wet reaction unit 4 may include a filling mechanism 44.

The filling mechanism (44) is coupled to the wet reaction chamber (41) so as to be located inside the wet reaction chamber (41). The filling mechanism (44) may be located between the inlet (42) and the injection mechanism (43). The filling mechanism 44 may include a filling material having a predetermined gap. Accordingly, the filling mechanism 44 can further increase the contact between the exhaust gas and the additive by delaying the movement of the exhaust gas and the movement of the additive in the aqueous solution state or the slurry state. Therefore, the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention can further improve the denitration efficiency for the denitrification process and the desulfurization efficiency for the desulfurization process.

The wet reacting unit 4 may be connected to the stack 20 through an exhaust duct 60. After the harmful substances have been removed through the secondary treatment process in the wet reaction unit 4, the flue gas may move along the discharge duct 60 and be discharged to the atmosphere through the stack 20. A blowing fan 100 for moving the exhaust gas may be coupled to the exhaust duct 60. The blowing fan 100 discharges the exhaust gas from the exhaust gas generating source 10 using a suction force and a wind power and supplies the exhaust gas discharged from the exhaust gas generating source 10 to the plasma reactor 2, 4), and the stack (20).

Referring to FIGS. 1 and 2, the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention may include a hydrocarbon feeder 5.

The hydrocarbon supply part 5 supplies hydrocarbon to the exhaust gas supplied to the plasma reaction part 2. For example, the hydrocarbon may be propylene (C ₃ H _6). Hydrocarbons supplied to the flue gas are reacted with oxygen atoms, ozone or the like located in the plasma reaction part 2 to produce RO ₂ peroxide (R = H, CH ₃ , HCO ₃ , C ₂ H ₃ , C ₂ H ₅ , . The RO ₂ peroxides can be by oxidizing the nitrogen monoxide to nitrogen dioxide more effectively, improving the efficiency of the primary process. Accordingly, the hydrocarbon supply unit 5 improves the efficiency of the primary treatment process per the amount of electric power supplied to the plasma chamber 21 by the control unit 22, so that the plasma reaction unit 2 The amount of power consumed can be reduced. Therefore, the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention can reduce the operating cost.

The hydrocarbon supply unit 5 may supply hydrocarbon to the inside of the plasma chamber 21. The hydrocarbon feeder (5) may supply hydrocarbon to the connecting duct (30). In this case, the hydrocarbon feeder 5 is connected to the connecting duct 30.

The hydrocarbon feeder 5 can regulate the conversion rate at which nitrogen dioxide is produced from nitrogen monoxide in the primary treatment process by adjusting the amount of hydrocarbon supplied to the plasma chamber 21. The hydrocarbon supply unit 5 can adjust the supply amount of hydrocarbon supplied to the plasma chamber 21 according to process conditions such as conversion ratios related to denitration efficiency, power consumption related to the operation cost, and operating conditions.

Although not shown, the hydrocarbon feeder 5 may include a hydrocarbon reservoir for storing hydrocarbons, and a hydrocarbon feeder for feeding the hydrocarbon stored in the hydrocarbon reservoir to the exhaust gas. The hydrocarbon supply means may include a damper, a flow rate control valve, and the like to adjust the amount of hydrocarbon supplied to the exhaust gas.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a method for removing harmful substances from a flue gas according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic flow chart of a method for removing harmful substances from a flue gas according to the present invention.

1 to 3, the method for removing harmful substances from the exhaust gas according to the present invention is for removing harmful substances from the exhaust gas discharged from the exhaust gas generating source 10. The method for removing harmful substances from the exhaust gas according to the present invention can be carried out using the apparatus 1 for removing harmful substances from the exhaust gas according to the present invention. The method for removing harmful substances from the exhaust gas according to the present invention includes the following configuration.

First, the exhaust gas is subjected to a plasma reaction (S10). This step S10 may be performed by causing the plasma reactor 2 to discharge the exhaust gas supplied from the exhaust gas generating source 10 and to cause a plasma reaction. Through the step S10 of plasma-reacting the exhaust gas, the primary treatment process can be performed. The primary treatment may be carried out according to Reaction Scheme 1 and Reaction Scheme 2.

Next, the additive is supplied (S20). This step (S20) may be performed by supplying the additive in the form of an aqueous solution or a slurry to the wet reacting section (4).

Next, the secondary treatment process is performed wet (S30). This step (S30) can be achieved by performing the denitrification process and the desulfurization process in parallel on the exhaust gas that has undergone the primary treatment process using the additive supplied from the additive supplier (3) have.

As described above, in the method for removing harmful substances from the exhaust gas according to the present invention, nitrogen monoxide, which is difficult to wet process, is converted into nitrogen dioxide which can be subjected to wet treatment through the primary treatment step, and then the aqueous solution or slurry- The denitrification process and the desulfurization process may be performed in parallel with the wet process. Therefore, the method for removing harmful substances from the exhaust gas according to the present invention can achieve the following operational effects.

Since the method for removing harmful substances from the exhaust gas according to the present invention is implemented to perform the denitrification process in a wet manner, it is possible to provide a facility for simultaneously performing the denitrification process and the desulfurization process . Therefore, the method for removing harmful substances from the exhaust gas according to the present invention can reduce the construction cost for constructing the denitrification equipment capable of performing both the denitrification process and the desulfurization process by reusing the existing wet desulfurization facility Can be reduced.

Since the denitrification process and the desulfurization process are implemented as wet processes, the denitrification process and the desulfurization process can be performed simultaneously with the flue gas temperature and below. Accordingly, the method for removing harmful substances from the exhaust gas according to the present invention does not require the temperature raising process and the temperature raising process required in the conventional denitrification process. Therefore, the method for removing harmful substances from the exhaust gas according to the present invention can reduce the construction cost and the operation cost by energy saving because there is no fuel consumption for heating.

Since the method for removing harmful substances from the exhaust gas according to the present invention converts nitrogen oxide into nitrogen dioxide having a high solubility through the primary treatment process, the denitrification process is carried out simultaneously with the desulfurization process, Can be implemented.

Since the denitrification process and the desulfurization process can be both wet type and the desulfurization process are performed under the same operation condition, when the different operating conditions are applied to the denitrification process and the desulfurization process, ≪ / RTI > can be reduced.

Referring to FIGS. 1 to 3, the step (S10) of plasma-reacting the exhaust gas may include a step (S11) of controlling the energy density.

The step of adjusting the energy density S11 may be performed by adjusting the amount of power supplied to the plasma chamber 21 by the control unit 22. [ Accordingly, the method for removing harmful substances from the exhaust gas according to the present invention can control the conversion rate at which nitrogen dioxide is produced from nitrogen monoxide in the primary treatment process according to process conditions and operating conditions through energy density control.

1 to 3, the step (S20) of supplying the additive may include a step (S21) of supplying an additive for denitration and a step (S22) of supplying an additive for desulfurization.

The step (S21) of supplying the denitration additive supplies the denitration additive that reacts with the nitrogen dioxide produced through the primary treatment step to generate nitrogen, to the wet reaction part (4) . The denitration additive supplied to the wet reactor 4 can be used in the denitrification process by being injected into the exhaust gas passed through the primary treatment process through the injection mechanism 43.

The step (S21) of supplying the denitration additive may be performed by supplying the denitration additive containing sodium sulfide to the wet reaction section (4). In this case, in the step (S30) of performing the secondary treatment process wet, the denitrification process may be performed according to the reaction formula (3).

The step (S21) of supplying the denitration additive may be performed by supplying the denitration additive containing sodium sulfite to the wet reaction section (4). In this case, in the step (S30) of performing the secondary treatment process wet, the denitrification process may be performed according to the reaction formula (4).

The step (S22) of supplying the desulfurizing additive is performed by supplying the desulfurizing additive, which reacts with the sulfur dioxide contained in the exhaust gas passed through the primary treatment step, to form an alkali salt, ). ≪ / RTI > The desulfurization additive supplied to the wet reactor 4 may be used in the desulfurization process by being injected into the exhaust gas that has undergone the primary treatment process through the injection mechanism 43.

The step of supplying the desulfurizing additive (S22) is a step of supplying the desulfurizing additive containing any one of magnesium hydroxide, sodium hydroxide, calcium carbonate and calcium hydroxide to the wet reacting section (4) . In the case where the additive supply unit 3 supplies the additive for desulfurization containing calcium hydroxide, the desulfurization step may be performed according to the reaction formula 5 and the reaction formula 6 in the step of performing the secondary treatment step in a wet manner (S30) .

The step (S22) of supplying the desulfurization additive and the step (S21) of supplying the denitration additive can be performed simultaneously. In this case, the additive supplying portion 3 can supply the wet reacting portion 4 with the mixed additive mixed with the denitration additive and the desulfurizing additive.

1 to 3, a method for removing harmful substances from a flue gas according to the present invention may include a step (S40) of supplying hydrocarbon.

The step (S40) of supplying the hydrocarbon may be performed by adjusting the amount of hydrocarbon supplied to the hydrocarbon feeder 5 and supplying the hydrocarbon to the flue gas. Accordingly, in the method for removing harmful substances from the exhaust gas according to the present invention, it is possible to control the conversion rate at which nitrogen dioxide is produced from nitrogen monoxide in the primary treatment process according to process conditions and operating conditions by controlling the supply amount of the hydrocarbon. The hydrocarbon supply unit 5 may supply hydrocarbon to the connection duct 30 or the plasma chamber 21. The step of supplying the hydrocarbon (S40) may be performed before the step (S10) of performing the plasma reaction of the exhaust gas.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. It will be obvious to those with knowledge.

1: Hazardous substance wet-type removal device for flue gas 2: Plasma reaction part
3: additive supply part 4: wet reaction part
5: Carbonization water supply unit 10: Flue gas generator

Claims (11)

In order to carry out the denitrification process and the desulfurization process wet with the nitrogen oxides and the sulfur oxides contained in the exhaust gas in parallel, a plasma reaction is performed in which the exhaust gas is plasma-reacted to produce nitrogen dioxide from the nitrogen monoxide contained in the exhaust gas part;
A wet reaction unit connected to the plasma reaction unit and performing a secondary treatment process in which the exhaust gas discharged from the plasma reaction unit is subjected to a denitration process and a desulfurization process; And
And an additive supply unit for supplying an aqueous solution or an additive in a slurry state to the wet reaction unit so that the secondary treatment process is performed in a wet manner,
The wet reacting portion includes an inlet formed to supply the exhaust gas discharged from the plasma reactor, a sprayer configured to spray the additive at a higher position than the inlet, and a filling mechanism positioned between the inlet and the sprayer ,
Wherein the filling mechanism comprises a filling material having a void. The method according to claim 1,
The additive supply unit may include an additive for desulfurization that reacts with sulfur dioxide contained in the exhaust gas to generate an alkali salt and a denitration additive that reacts with the nitrogen dioxide produced through the primary treatment to produce nitrogen, A device for removing harmful substances from a flue gas. delete The method according to claim 1,
A hydrocarbon supply part for supplying hydrocarbon to the exhaust gas supplied to the plasma reaction part, and a control unit for controlling an energy density of electric power to be supplied to the plasma reaction part,
Wherein the hydrocarbon supply unit and the control unit adjust the hydrocarbon supply amount and the electric power amount, respectively, to control the conversion ratio at which nitrogen dioxide is produced from nitrogen monoxide in the primary treatment process. The method according to claim 1,
Wherein the additive supplying unit supplies a denitration additive containing sodium sulfide or sodium sulfite so that nitrogen and sodium salt are generated by reacting with nitrogen dioxide in the secondary treatment step. The method according to claim 1,
Wherein the additive supply unit supplies an additive for desulfurization containing any one of magnesium hydroxide, sodium hydroxide, calcium carbonate, and calcium hydroxide. A method for removing harmful substances from a flue gas by performing a denitrification process and a desulfurization process in combination with nitrogen oxides and sulfur oxides contained in the flue gas,
Subjecting the exhaust gas to a plasma reaction so as to perform a primary treatment process for producing nitrogen dioxide from the nitrogen monoxide contained in the exhaust gas;
Supplying an additive in an aqueous solution state or a slurry state to an exhaust gas passed through the primary treatment step; And
And performing a secondary treatment process in which the denitration process and the desulfurization process are performed in parallel with the exhaust gas that has undergone the primary treatment process using the additive in a wet manner,
Wherein the additive is injected toward the exhaust gas by an injection mechanism at a position higher than that of the exhaust gas in the step of performing the secondary treatment step in a wet manner, and the exhaust gas and the additive are mixed with an inlet through which the exhaust gas flows, Wherein the movement is delayed by a filling mechanism which is located between the devices and includes a filling material having a void. 8. The method of claim 7, wherein supplying the additive comprises:
Providing an additive for desulfurization that reacts with sulfur dioxide contained in the flue gas to produce an alkali salt; And
And supplying a denitration additive that reacts with the nitrogen dioxide generated through the primary treatment process to generate nitrogen, thereby removing harmful substances from the exhaust gas. 8. The method of claim 7,
And adjusting the supply rate of the hydrocarbon to regulate the conversion rate at which nitrogen dioxide is produced from the nitrogen monoxide in the primary treatment step before supplying the exhaust gas to the exhaust gas before the plasma reaction of the exhaust gas,
Wherein the step of subjecting the exhaust gas to a plasma reaction includes the step of adjusting an energy density of electric power for plasma reaction of the exhaust gas to control a conversion ratio at which nitrogen dioxide is produced from nitrogen monoxide in the primary treatment step For removing harmful substances. 8. The method of claim 7,
Wherein the step of supplying the additive comprises the step of supplying a denitration additive containing sodium sulfide or sodium sulfite,
The step of performing the secondary treatment process wet-
When the denitration additive containing sodium sulfide is supplied to the exhaust gas after the primary treatment, the denitrification process is performed with the reaction formula 2NO ₂ + Na ₂ S → N ₂ + Na ₂ SO ₄ ,
Wherein a denitration additive containing sodium sulfite is supplied to the exhaust gas that has undergone the primary treatment, the denitrification process is performed with the reaction formula 2NO ₂ + 4Na ₂ SO ₃ → N ₂ + 4Na ₂ SO ₄ Wet removal method of harmful substances. 8. The method of claim 7,
Wherein the step of supplying the additive comprises the step of supplying an additive for desulfurization containing calcium hydroxide,
Performing the second treatment step with liquid, the desulfurization process scheme _{2SO 2 + 2Ca (OH) 2} + O 2 → 2CaSO 4 + 2H 2 O and _{SO 2 + Ca (OH) 2} → CaSO 3 + H 2 O to the flue gas.

Images