KR101474281B1 - Application and Control Method of Aftertreatment System for Vehicle/Engine to Reduce Ammonia Slip using AOC - Google Patents

Abstract

The present invention relates to a catalyst purifying apparatus and method for purifying ammonia slip using an AOC catalyst, and more particularly, to a catalyst purifying apparatus and method for purifying ammonia slip using exhaust gas The ammonia slip is oxidized by using the first AOC catalyst device and the second AOC catalyst device, respectively, or in combination, thereby oxidizing the ammonia slip that can not be oxidized by the conventional catalyst or the SCR catalyst, The NOx is purified by the second catalytic device to minimize the exhaust of NOx to the outside, which is lower than the exhaust gas harmful component emission reference value, thereby preventing environmental pollution.

Description

TECHNICAL FIELD [0001] The present invention relates to a catalyst purification apparatus and method for purifying ammonia slip using an AOC catalyst,

The present invention relates to a catalyst purifying apparatus and method for purifying ammonia slip using an AOC catalyst, and more particularly, to a catalyst purifying apparatus and method for purifying ammonia slip using exhaust gas The ammonia slip is oxidized by using the first AOC catalyst device and the second AOC catalyst device, respectively, or in combination, thereby oxidizing the ammonia slip that can not be oxidized by the conventional catalyst or the SCR catalyst, Catalyst for purifying the ammonia slip by using an AOC catalyst capable of preventing environmental pollution by minimizing the emission of NOx to the outside by lowering the exhaust gas harmful component emission standard value by purifying NOx by the second catalytic device A purifier and a control method.

An engine after-treatment apparatus of a general gasoline vehicle is exhausted after exhaust gas generated during operation of the engine is exhausted after the first catalytic treatment and the second catalytic treatment before exhausting to the outside.

Here, the catalyst has a catalytic temperature of 250 ° C or higher so that the exhaust gas reducing capability is properly exhibited. Therefore, it is the catalyst device that is installed closest to the engine so that the unburned gas generated at the start including the cold start can be cleaned quickly.

And, the secondary catalyst is a catalyst device installed for treating the exhaust gas which is not purified by the primary catalyst. Finally, a silencer is installed at the rear end of the secondary catalytic device to reduce exhaust noise.

An elemental SCR system for reducing NOx in the exhaust gas discharged from a general engine has been developed. This urea SCR system uses a SCR catalyst that converts NOX to nitrogen (N2) and water (H2O) by a chemical reaction between ammonia (NH3) and NOX generated by the hydrolysis of urea water.

Here, the SCR catalyst is provided in the exhaust gas passage between the engine and the muffler. Further, an injection valve for injecting the oxidation catalyst and the urea water into the exhaust gas is provided on the upstream side of the SCR catalyst. The oxidation catalyst oxidizes hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas to water (H2O) and carbon dioxide (CO2) and also promotes oxidation of nitrogen oxides (NO) to nitrogen dioxide (NO2).

A diesel particulate filter (DPF) for reducing particulate matter (PM) such as carbon in the exhaust gas is also provided in the exhaust gas passage between the engine and the muffler. The exhaust gas purifying apparatus including the urea SCR system and the DPF has many components provided between the engine and the muffler and also requires a large space for installing such components in the vehicle. Therefore, the urea SCR system must be small in size and also achieve NO x reduction efficiently in terms of urea consumption.

A platinum-containing preliminary catalyst having a function of filtering PM in the exhaust gas, an SCR catalyst provided on the downstream side of the platinum-containing preliminary catalyst, and a first feeder provided on the upstream side of the platinum-containing preliminary catalyst to supply ammonia or urea And a second supply device provided between the apparatus and the platinum-containing preliminary catalyst and the SCR catalyst for supplying ammonia or urea. The platinum-containing pre-catalyst functions as a reduction catalyst at a temperature of less than about 250 ° C and also as an oxidation catalyst at a temperature of at least about 250 ° C. The SCR catalyst is activated as a reducing catalyst at a temperature above about 250 < 0 > C.

When the temperature of the exhaust gas is at T1 between 220 ° C and 270 ° C, ammonia or urea is fed from the first feeder, and ammonia generated by the hydrolysis of the urea in the ammonia or platinum containing pre- NOx is reduced. If the temperature of the exhaust gas exceeds T1, ammonia or urea is fed from the second feeder, and then the ammonia generated in the SCR catalyst by the hydrolysis of ammonia or urea reduces the NOx in the exhaust gas. Oxidation of ammonia in the platinum-containing pre-catalyst is prevented by feeding ammonia or urea in the second feed unit. Therefore, the exhaust gas purifying apparatus efficiently uses the supplied ammonia or urea to reduce NOx.

However, when the element is supplied from the first supply device or the second supply device in the exhaust gas purifier, the supplied element is supplied upstream of the platinum-containing preliminary catalyst or the SCR catalyst before reaching the platinum- Should be long enough to ensure that the element is sufficiently long to be hydrolyzed to ammonia. The distance between the first feed device and the platinum-containing pre-catalyst and the distance between the second feed device and the SCR catalyst must be sufficiently long, respectively, for the hydrolysis of the elements. Therefore, there is a problem in that the device has to be increased in its length and it is also difficult to make the device small.

Korean Patent Publication No. 10-2011-0025133 Korean Patent Publication No. 10-2012-0042778 Korean Patent Publication No. 10-0642701

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art,

The ammonia slip of the exhaust gas generated in the engine for a vehicle which is used either separately or in combination with the gasoline and the ammonia liquid fuel is purified by using the first AOC catalyst device and the second AOC catalyst device, Or the ammonia slip which can not be oxidized by the SCR catalyst is oxidized and the NOx generated during oxidation of the ammonia is purified by the second catalytic device to minimize the exhaust of NOx to the outside to lower the exhaust gas harmful component emission standard value, Which is capable of preventing ammonia slip by using an AOC catalyst capable of preventing ammonia slip.

In order to accomplish the above object, the present invention provides an ammonia (NH₃) slip purifier for exhaust gas generated from an engine for a vehicle, which is used in combination with gasoline and ammonia liquid fuel,

A first catalyst device for purifying the exhaust gas generated in the vehicle engine;

The ammonia slip in the exhaust gas purified by the first catalytic device installed in the vicinity of the first catalytic device is oxidized by the AOC oxidation catalyst. When the temperature of the exhaust gas is within the set range, the first AOC catalytic device ;

Wherein the ammonia slip in the exhaust gas purified by the first catalytic converter is oxidized by the AOC oxidation catalyst, the ammonia slip being connected to the first catalytic converter and being located at a higher temperature than the first AOC catalytic converter in the first catalytic converter, And when the temperature is within the set range, the first oxidized exhaust gas is delivered from the first AOC catalytic device to secondary oxidation, and when the temperature of the exhaust gas exceeds the set range, A second AOC catalytic device for directly oxidizing the ammonia slip;

And a second catalytic device for secondarily purifying the exhaust gas purified in the first AOC catalytic device or the second AOC catalytic device. The catalyst purifying device for a vehicle for purifying ammonia slip using an AOC catalyst .

The present invention also provides a control method for a catalytic purifier for purifying an ammonia slip using an AOC catalyst,

(S100) selectively delivering the exhaust gas to the first AOC catalyst device and the second AOC catalyst device according to the set conditions of the vehicle and the exhaust gas after the exhaust gas generated in the engine is firstly purified by the first catalyst device, ;

In the step S100 of selectively transmitting the exhaust gas, when the vehicle is initially started or when the temperature of the exhaust gas is in the set range, the first solenoid valve is turned ON and the second solenoid valve is turned OFF, Oxidizing the ammonia slip in the step (S200);

The first solenoid valve is turned OFF and the second solenoid valve is turned ON when the temperature of the exhaust gas is high or higher than the predetermined range, Oxidizing the ammonia slip in the exhaust gas in the apparatus (S300);

And a step (S400) of exhausting the oxidized exhaust gas from the second AOC catalytic device to the outside through a silencer after being secondarily purified by the second catalytic device (S400). The ammonia slip The present invention relates to a control method for a catalyst purifying apparatus for a vehicle.

As described above, the catalyst purifying apparatus and method for purifying the ammonia slip using the AOC catalyst of the present invention for a vehicle / engine can be applied to exhaust gas emitted from an engine for a vehicle, which is used by mixing gasoline and ammonia liquid fuel, The ammonia slip is oxidized by using the first AOC catalyst device and the second AOC catalyst device, respectively, or in combination, thereby oxidizing the ammonia slip that can not be oxidized by the conventional catalyst or the SCR catalyst, The NOx is purified by the second catalytic device to minimize the exhaust of NOx to the outside, which is lower than the exhaust gas harmful component emission reference value, thereby preventing environmental pollution.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a catalyst purifying apparatus for a vehicle purifying an ammonia slip using an AOC catalyst according to an embodiment of the present invention,
2 is a flowchart showing a control method of a catalyst purifying apparatus for a vehicle purifying ammonia slip using an AOC catalyst according to an embodiment of the present invention.

The present invention has the following features in order to achieve the above object.

The present invention relates to an ammonia (NH₃) slip purifier for exhaust gas generated in an engine for a vehicle which is used by mixing gasoline and ammonia liquid fuel,

A first catalyst device for purifying the exhaust gas generated in the vehicle engine;

The ammonia slip in the exhaust gas purified by the first catalytic device installed in the vicinity of the first catalytic device is oxidized by the AOC oxidation catalyst. When the temperature of the exhaust gas is within the set range, the first AOC catalytic device ;

Wherein the ammonia slip in the exhaust gas purified by the first catalytic converter is oxidized by the AOC oxidation catalyst, the ammonia slip being connected to the first catalytic converter and being located at a higher temperature than the first AOC catalytic converter in the first catalytic converter, And when the temperature is within the set range, the first oxidized exhaust gas is delivered from the first AOC catalytic device to secondary oxidation, and when the temperature of the exhaust gas exceeds the set range, A second AOC catalytic device for directly oxidizing the ammonia slip;

And a second catalytic device for secondarily purifying the exhaust gas purified in the first AOC catalytic device or the second AOC catalytic device.

The present invention also provides a control method for a catalytic purifier for purifying an ammonia slip using an AOC catalyst,

(S100) selectively delivering the exhaust gas to the first AOC catalyst device and the second AOC catalyst device according to the set conditions of the vehicle and the exhaust gas after the exhaust gas generated in the engine is firstly purified by the first catalyst device, ;

In the step S100 of selectively transmitting the exhaust gas, when the vehicle is initially started or when the temperature of the exhaust gas is in the set range, the first solenoid valve is turned ON and the second solenoid valve is turned OFF, Oxidizing the ammonia slip in the step (S200);

The first solenoid valve is turned OFF and the second solenoid valve is turned ON when the temperature of the exhaust gas is high or higher than the predetermined range, Oxidizing the ammonia slip in the exhaust gas in the apparatus (S300);

The exhaust gas oxidized in the second AOC catalytic device is secondarily purified in the second catalytic device, and then discharged to the outside through a silencer (S400).

The present invention having such characteristics can be more clearly described by the preferred embodiments thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing in detail several embodiments of the present invention with reference to the accompanying drawings, it is to be understood that the present invention is not limited to the details of construction and the arrangement of components shown in the following detailed description or illustrated in the drawings will be. The invention may be embodied and carried out in other embodiments and carried out in various ways. It should also be noted that the device or element orientation (e.g., "front," "back," "up," "down," "top," "bottom, Expressions and predicates used herein for terms such as "left," " right, "" lateral, " and the like are used merely to simplify the description of the present invention, Or that the element has to have a particular orientation. Also, terms such as " first "and" second "are used herein for the purpose of the description and the appended claims, and are not intended to indicate or imply their relative importance or purpose.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

FIG. 1 is a schematic view showing a catalyst purifying apparatus for a vehicle for purifying ammonia slip using an AOC catalyst according to an embodiment of the present invention. FIG. 2 is a schematic view showing the purification of ammonia slip using an AOC catalyst according to an embodiment of the present invention. Fig. 2 is a flowchart showing a control method of a catalyst purifying apparatus for a vehicle. Fig.

As shown in FIG. 1, the apparatus for purifying ammonia slip using the AOC catalyst of the present invention is a device for purifying ammonia slip, which comprises a harmful substance of exhaust gas generated in a vehicle engine used for gasoline and ammonia liquid fuel, The first AOC catalyst device 20, the second AOC catalyst device 30 and the second catalyst device 40. The first catalyst device 10, the first AOC catalyst device 20, the second AOC catalyst device 30, At this time, the components are connected by an exhaust gas transfer pipe (70) connected to the engine (1).

The first catalytic device 10 and the second catalytic device 40 purify the harmful substances in the exhaust gas while the exhaust gas generated in the engine 1 passes through the catalytic device containing the conventional catalytic agent, The catalytic device 10 is located at a position closest to the engine 1 and the second catalytic device 40 is located farthest from the engine 1 to purify exhaust gas which is finally exhausted.

Here, the catalysts of the first catalytic device 10 and the second catalytic device 40 include ordinary oxidation catalysts, SCR catalysts, etc. At this time, the "SCR" means that the catalytic reaction of the reducing agent and the nitrogen oxides To selective catalytic reduction of nitrogen oxides, that is, N2O to N2. The reducing agent may be supplied via a combination of external, internal, or external and internal sources, as the hydrocarbons in the exhaust gas may function as a reducing agent. As described below, the SCR catalyst is reduced upon reaction with NOX, but need not be a reduction catalyst alone. Oxidation reaction may occur.

1, the first AOC catalytic device 20 is installed near the first catalytic device 10, that is, at a distance H₁ closer to the second AOC catalytic device 30, The ammonia (NH₃) slip in the exhaust gas purified in the first catalytic converter 10 is oxidized by the AOC oxidation catalyst. When the temperature of the exhaust gas is within the set range, the first AOC catalytic device 20 is used. At this time, the AOC is an abbreviation of ammonia oxidation catalyst, which means an ammonia oxidation catalyst, which is a catalyst for oxidizing ammonia.

The exhaust gas transfer pipe 70 connected to the outlet of the first catalytic device 10 is branched so that one exhaust gas transfer pipe 70 is connected to the first AOC catalytic device 20, The transfer pipe 70 is connected to the second AOC catalytic device 30 so that the exhaust gas purified in the first catalytic device 10 is supplied to the first AOC catalytic device 20 and the second AOC catalytic device 30 Respectively. The description of the setting condition will be described in detail in the following control method.

The exhaust gas transfer pipe 70 connected to the outlet side of the first AOC catalytic device 20 is configured such that the ammonia slip of the exhaust gas is firstly oxidized in the first AOC catalytic device 20, Is connected to the inlet side exhaust gas transfer pipe (70) of the second AOC catalytic device (30) to be secondarily oxidized in the device (30). At this time, the exhaust gas transfer pipe (70) connected to the first AOC catalytic device (20) is connected to both sides in the form of a bypass pipe.

1, the second AOC catalytic device 30 is connected to the first catalytic device 10 by an exhaust gas transfer pipe 70. At this time, 1 AOC catalyst device 20 so that the ammonia slip in the exhaust gas purified in the first catalytic device 10 is oxidized by the AOC oxidation catalyst. At this time, when the temperature of the exhaust gas exceeds the set range A second AOC catalytic device 30 is used.

Here, the second AOC catalytic device 30 is connected to another exhaust gas conveying pipe 70 branched from the exhaust gas conveying pipe connected to the first AOC catalytic device 20, and is purified in the first catalytic device 10 The exhaust gas is delivered to the first AOC catalytic device 20 and the second AOC catalytic device 30, respectively, in accordance with the setting conditions. The description of the setting condition will be described in detail in the following control method.

The exhaust gas transfer pipe 70 connected to the outlet side of the second AOC catalytic device 30 is connected to the second catalytic device 40 so that exhaust gas oxidized up to the second order is transferred.

The exhaust gas transfer pipe 70 is connected to the outlet of the first catalytic device 10 so that the exhaust gas is delivered to the first AOC catalytic device 20 and the second AOC catalytic device 30, The branched exhaust gas transfer pipe 70 is connected to the first AOC catalytic device 20 and the second AOC catalytic device 30 by a first solenoid valve 70 so as to control the exhaust gas to be delivered to the first AOC catalytic device 20 and the second AOC catalytic device 30, A valve 51 and a second solenoid valve 52 are provided, respectively.

The first solenoid valve 51 and the second solenoid valve 52 are further provided with a control unit 50 for controlling the opening and closing of the exhaust gas transfer pipe 70 according to the set conditions, 1, the first solenoid valve 51 and the second solenoid valve 52 are connected to each other in accordance with the setting conditions received by the engine 1 and the temperature sensor 53 provided at the outlet side of the engine 1, .

1, a silencer 60 is further installed on the exhaust side of the second catalytic device 40 to reduce the noise generated when the finally purified exhaust gas is transported to the outside before being discharged.

Hereinafter, a control method of the catalytic purifier for purifying the ammonia slip using the AOC catalyst will be described in detail with reference to the drawings.

As shown in FIGS. 1 and 2, a method for controlling a catalytic converter purifying apparatus for purifying an ammonia slip using an AOC catalyst according to the present invention is characterized in that exhaust gas generated in the engine 1 is supplied to a first catalytic converter 10 The exhaust gas is selectively delivered to the first AOC catalytic device 20 and the second AOC catalytic device 30 according to the engine 1 motions of the vehicle and the exhaust gas setting conditions. S100)

The first solenoid valve 51 is turned on and the second solenoid valve 52 is turned off so that the first catalyst device 10 is turned off in the first catalyst device 10, The cleaned exhaust gas is transferred to the first AOC catalytic device 20 to oxidize the ammonia slip in the exhaust gas in the first AOC catalytic device 20. S200 At this time, (Low pressure) and the temperature of the exhaust gas is low. That is, when the driver starts immediately after starting, the first AOC catalytic device 20 is used because the cooling water temperature can not reach 40 degrees. The set temperature of the exhaust gas ranges from 200 to 300 占 폚, and is a temperature range in which no deterioration of the AOC oxidation catalyst occurs.

The exhaust gas obtained by firstly oxidizing the ammonia slip in the first AOC catalytic device 20 is transferred to the second AOC catalytic device 30 along the exhaust gas transfer pipe 70 to be secondarily oxidized, And is delivered to the catalyst device 40.

The first solenoid valve 51 is turned off and the second solenoid valve 52 is turned on when the vehicle is suddenly accelerated or rapidly accelerated or when the temperature of the exhaust gas is higher than a predetermined range, The exhaust gas purified at the first catalytic converter 10 is transferred to the second AOC catalytic device 30 to oxidize the ammonia slip in the exhaust gas at the second AOC catalytic device 30. At this time, The temperature of the exhaust gas is high and the temperature of the exhaust gas is 400 DEG C or more. The second AOC catalytic device 30 is used when the cooling water temperature is 40 DEG C or more and the throttle opening is 60% or more.

Here, the cooling water temperature of 40 ° C is a condition that the exhaust gas temperature passed through the first catalytic device 10 is 400 ° C or higher under the condition that the idle state is stabilized and the exhaust gas temperature at which the AOC sufficiently oxidizes ammonia has reached 400 ° C , The ammonia oxidation by the AOC is sufficiently performed, so that the second AOC catalyst device 30 is immediately passed without passing through the first AOC catalyst device 20.

Also, in most gasoline vehicles, the throttle opening degree of 60% means 70% or more of the maximum output based on the engine output, and the temperature of the exhaust gas (after the first catalytic device) at that time may exceed 700 ° C. At this time, if the exhaust gas temperature exceeds 700 ° C., there is a high possibility of damaging the AOC catalyst. Therefore, in order to protect the AOC oxidation catalyst of the first AOC catalyst device 20 close to the first catalyst device 10, 20 to the second AOC catalytic device 30 installed at a distance H2 higher than the installation distance H2 of the first AOC catalytic device 20 in the first catalytic device 10, Since the temperature of the exhaust gas is high, the temperature of the exhaust gas is lowered during the transfer process, thereby preventing deterioration of the AOC catalyst.

Finally, the exhaust gas oxidized in the second AOC catalytic device 30 is secondarily purified in the second catalytic device 40 and then discharged to the outside through the silencer 60. In step S400,

10: first catalytic device 20: first AOC catalytic device
30: second AOC catalyst device 40: second catalyst device
50: control unit 51: first solenoid valve
52: second solenoid valve 53: temperature sensor
60: silencer 70: exhaust gas conveying pipe

Claims (11)

An ammonia (NH₃) slip purifier for an exhaust gas generated from an engine for a vehicle which is used by mixing gasoline and ammonia liquid fuel, respectively,
A first catalyst device (10) for purifying the exhaust gas generated in the vehicle engine (1) first;
The ammonia slip in the exhaust gas purified by the first catalytic device 10 is oxidized by the AOC oxidation catalyst when the temperature of the exhaust gas is within the set range , A first AOC catalytic device 20 used;
The first catalytic device 10 is connected to the first catalytic device 10 and is provided at a higher position H2 than the first catalytic device 20 in the first catalytic device 10, The slip is oxidized by the AOC oxidation catalyst. When the exhaust gas temperature is within the predetermined range, the first oxidized exhaust gas is transferred from the first AOC catalytic device 20 to secondary oxidation, and the temperature of the exhaust gas A second AOC catalytic device (30) for directly oxidizing the ammonia slip in the exhaust gas purified in the first catalytic device (10) when the setting range is out of order;
A second catalytic device 40 for secondarily purifying the exhaust gas purified in the first AOC catalytic device 20 or the second AOC catalytic device 30;
Wherein the ammonia slip is purified using an AOC catalyst.
The method according to claim 1,
The first catalytic device 10 and the first AOC catalytic device 20 and the second AOC catalytic device 30 and the second catalytic device 40 are interconnected by the exhaust gas transfer pipe 70 from the engine A catalyst purifying apparatus for a vehicle which purifies ammonia slip using an AOC catalyst.
3. The method of claim 2,
An exhaust gas transfer pipe 70 is branched and connected to the exhaust port side of the first catalytic device 10 so that the exhaust gas is transferred to the first AOC catalytic device 20 and the second AOC catalytic device 30, Wherein the ammonia slip is purified using an AOC catalyst.
The method of claim 3,
The branched exhaust gas transfer pipe 70 is provided with a first solenoid valve 51 and a second solenoid valve 51 so as to control the exhaust gas to be transferred to the first AOC catalytic device 20 and the second AOC catalytic device 30, And a second solenoid valve (52) are provided in the exhaust passage (52), respectively, to purify the ammonia slip using the AOC catalyst.
5. The method of claim 4,
The first solenoid valve 51 and the second solenoid valve 52 are further provided with a control unit 50 for controlling the opening and closing of the exhaust gas transfer pipe 70 according to the set conditions. A catalyst purifying device for vehicles purifying ammonia slip.
The method of claim 3,
The exhaust gas transfer pipe 70 connected to the first AOC catalytic device 20 is configured such that the ammonia slip of the exhaust gas is firstly oxidized in the first AOC catalytic device 20 and then oxidized in the second AOC catalytic device 30 Side exhaust gas transfer pipe (70) of the second AOC catalytic device (30) so as to oxidize the ammonia slurry, the ammonia slip is purified using the AOC catalyst.
A method for controlling a catalytic purifier for purifying an ammonia slip using an AOC catalyst,
After the exhaust gas generated in the engine 1 is firstly purified by the first catalytic converter 10, the exhaust gas is exhausted from the first AOC catalytic device 20 and the second AOC catalytic device 20 in accordance with the setting conditions of the vehicle and the exhaust gas. (S100);
The first solenoid valve 51 is turned ON and the second solenoid valve 52 is turned OFF when the vehicle is initially started or when the temperature of the exhaust gas is within the set range in the step S100 of selectively transmitting the exhaust gas, Oxidizing the ammonia slip in the exhaust gas in the AOC catalytic device (S200);
The first solenoid valve 51 is OFF and the second solenoid valve 52 is OFF when the temperature of the exhaust gas is high or higher than the predetermined range in the step S100 of selectively transmitting the exhaust gas, (S300) by turning on the ammonia slip in the exhaust gas in the second AOC catalytic device (30);
The exhaust gas oxidized in the second AOC catalytic device 30 is secondarily purified in the second catalytic device 40 and then discharged to the outside through the silencer 60,
In the step S200 of oxidizing the ammonia slip in the exhaust gas by the first AOC catalytic device 20,
The exhaust gas obtained by first oxidizing the ammonia slip in the first AOC catalytic device 20 is transferred to the second AOC catalytic device 30 and is secondarily oxidized and then transferred to the second catalytic device 40 Wherein the ammonia slip is purified using an AOC catalyst.
8. The method of claim 7,
In the step S200 of oxidizing the ammonia slip in the exhaust gas by the first AOC catalytic device 20,
Wherein the first AOC catalytic device (20) is used when the temperature of the exhaust gas is 200 to 300 ° C.
8. The method of claim 7,
The second AOC catalytic device 30 is provided at a distance H2 higher than the installation distance H2 of the first catalytic device 20 in the first catalytic device 10 so that even if the temperature of the exhaust gas is high, Wherein the ammonia slip is oxidized while the temperature is lowered to prevent deterioration of the AOC catalyst, thereby purifying the ammonia slip using the AOC catalyst. delete delete

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