KR102204182B1 - Exhaust System for Corrosion of SCR Chamber - Google Patents

Abstract

The present invention relates to an exhaust system capable of preventing corrosion of an SCR reactor that minimizes corrosion inside the reactor by forcibly removing exhaust gas remaining in the reactor by introducing external air after blocking the SCR reactor.
The exhaust system capable of preventing corrosion of the SCR reactor according to the present invention includes an SCR inlet line 20 connected and extended in the middle of the exhaust pipe 10 connected to the exhaust side of the engine 2; SCR reactor 30 installed in the SCR inlet line 20; An exhaust passage opening/closing valve 12 installed in the exhaust pipe 10 on the downstream side of the connection point of the SCR inlet line 20; An SCR outlet line 40 extending from the outlet of the SCR reactor 30 and connected to the exhaust pipe 10 downstream of the exhaust passage opening/closing valve 12; A first SCR on-off valve (22) installed in the SCR inlet line (20) and a second SCR on-off valve (42) installed in the SCR outlet line (40); An air blower 50 for blowing air for blowing; A blowing line 54 for forcibly discharging exhaust gas remaining in the SCR reactor 30 by blowing air blown from the air blower 50 into the SCR reactor 30; And a blowing line opening/closing valve 52 installed in the blowing line 54.

Description

Exhaust System for Corrosion of SCR Chamber to prevent corrosion of SCR reactor

The present invention relates to an exhaust system having a selective catalytic reduction system for removing nitrogen oxides contained in exhaust gas discharged after combustion of an engine, and more particularly, after shutting off the SCR reactor, external air is introduced to remain inside the reactor. The present invention relates to an exhaust system capable of preventing corrosion of an SCR reactor, which can prevent corrosion of an SCR reactor that can minimize internal corrosion of the reactor by forcibly removing exhaust gas.

The SCR system, referred to as a selective catalyst reduction system, is a system for selectively removing nitrogen oxides (NOx) in exhaust gases emitted from diesel engines for propulsion of ships, diesel engines for plant power generation, turbine generators, and the like.

Such an SCR system includes an SCR reactor (SCR Chamber) in which a catalyst is incorporated in the middle of an exhaust pipe, and a reducing agent supply device for supplying a reducing agent such as urea water into the exhaust gas.

When the reducing agent is sprayed from the spray nozzle on the exhaust gas discharged from the engine and headed to the SCR reactor, fine particles of the sprayed reducing agent are mixed with the exhaust gas to enter the SCR reactor and pass through the catalyst, and hydrolysis from the reducing agent in the process of passing the catalyst The resulting ammonia and exhaust gas react, and nitrogen oxides, which are harmful substances in the exhaust gas, are reduced to nitrogen and water vapor and removed.

1 shows an exhaust system of a conventional diesel engine equipped with an SCR reactor as an example.

As shown in Fig. 1, the SCR introduction line 31 is branched from the exhaust pipe 10 of the engine 2, and a turbocharger 6 is installed in the exhaust pipe 10, and the SCR introduction line 31 is an SCR reactor. (30) is installed, and the exhaust gas passes through the SCR reactor (30) by selectively opening and closing the valves (12) or SCR of the exhaust pipe (10), and the valves (32, 35) on the outlet lines (31, 34). Or, it is discharged directly through the turbocharger 6 without passing through the SCR reactor 30. In FIG. 1, '4' is a'exhaust gas receiver', '6a' is a'turbine' of a turbocharger, and '6b' is a'compressor' of a turbocharger.

That is, to remove nitrogen oxides in the exhaust gas, open the valves 32 and 35 installed between the lines 31 and 34 before and after the SCR reactor 30, and the exhaust pipe 20 connected to the turbocharger 6 By closing the valve 22, the exhaust gas is passed through the SCR reactor 30 to react with the catalyst inside the SCR reactor 30.

In addition, when the SCR reactor 30 is not used, the valves 32 and 35 installed on the lines 31 and 34 before and after the SCR reactor 30 are closed, and the exhaust pipe 20 connected to the turbocharger 6 is closed. The valve 22 is opened so that the exhaust gas is discharged without passing through the SCR reactor 30.

However, in the case of converting the SCR reactor 30 from use to non-use, the valves 32 and 35 installed on the lines 31 and 34 before and after the SCR reactor 30 are closed to prevent exhaust gas inside the SCR reactor 30. In this state, when the temperature of the exhaust gas decreases after a longer period of time in this state, sulfuric acid is generated and the inner surface of the SCR reactor 30 is corroded.

For this reason, the SCR reactor 30 and internal parts cannot be made of carbon steel, which is a general pipe material, and must be made of expensive stainless steel material.

Publication Patent Publication No. 10-2012-0126509 Registered Patent Publication No. 10-1344123

The present invention was developed to solve the above problems, and an object of the present invention is to provide an exhaust system that minimizes corrosion inside the reactor by removing exhaust gas remaining inside the reactor after blocking the SCR reactor. have.

In order to achieve the above object, the exhaust system capable of preventing corrosion of the SCR reactor according to the present invention is an SCR inlet line 20 connected and extended in the middle of the exhaust pipe 10 connected to the exhaust side of the engine 2 ; SCR reactor 30 installed in the SCR inlet line 20; An exhaust passage opening/closing valve 12 installed in the exhaust pipe 10 on the downstream side of the connection point of the SCR inlet line 20; An SCR outlet line 40 extending from the outlet of the SCR reactor 30 and connected to the exhaust pipe 10 downstream of the exhaust passage opening/closing valve 12; A first SCR on-off valve (22) installed in the SCR inlet line (20) and a second SCR on-off valve (42) installed in the SCR outlet line (40); An air blower 50 for blowing air for blowing; A blowing line 54 for forcibly discharging exhaust gas remaining in the SCR reactor 30 by blowing air blown from the air blower 50 into the SCR reactor 30; It comprises a blowing line opening and closing valve 52 installed in the blowing line 54.

In the exhaust system according to the present invention, the SCR reactor ( A first connection line 61 for sending and discharging the blown air containing exhaust gas coming out of 30 to the exhaust pipe 10; A first line opening/closing valve 62 for opening and closing the first connection line 61 may be further included.

Alternatively, the SCR reactor 30 is separately extended from the SCR outlet line 40 or from the outlet side of the SCR reactor 30 and is connected to the exhaust pipe 10 between the exhaust passage opening/closing valve 12 and the turbocharger 6. A second connection line 63 for discharging the blown air containing residual exhaust gas from the exhaust pipe 10 to the inlet side of the turbocharger 6; A second line on/off valve 64 for opening and closing the second connection line 63 may be further included.

In the exhaust system according to the present invention, an external discharge line 65 for discharging the blown air to the outside by extending separately from the SCR outlet line 40 or from the outlet side of the SCR reactor 30; An external line opening/closing valve 66 installed on the external discharge line 65 may be further included.

An exhaust system according to the present invention, comprising: an SCR inlet line 20 connected and extended in the middle of the exhaust pipe 10 connected to the exhaust side of the engine 2; SCR reactor 30 installed in the SCR inlet line 20; An SCR outlet line 40 extending from the outlet of the SCR reactor 30 and connected to the exhaust pipe 10 on the downstream side of the on-off valve 12; A first SCR on-off valve (22) installed in the SCR inlet line (20) and a second SCR on-off valve (42) installed in the SCR outlet line (40); An external air inlet line 100 and an inlet line opening/closing valve 102 that are separately installed at the inlet side of the SCR reactor 30 to introduce air for blowing into the SCR reactor 30; A residual gas discharge line 110 that extends separately from the SCR reactor 30 on the opposite side of the external air inlet line 100; A ventilation fan 120 installed in the residual gas discharge line 110 to draw external air from the external air inlet line 100 and discharge it to the outside together with the exhaust gas remaining inside the SCR reactor 30 I can.

Here, the outlet of the ventilation fan 120 is connected to the exhaust pipe 10 on the downstream side of the exhaust passage opening/closing valve 12 through an extension line 130 to discharge the exhaust gas-containing exhaust air from the SCR reactor 30. It can be configured to discharge to the exhaust pipe (10).

According to the exhaust system capable of preventing corrosion of the SCR reactor according to the present invention, the generation of sulfuric acid and the generation of sulfuric acid by discharging the exhaust gas remaining inside the SCR reactor through a separate removal line using a blower or a ventilation fan after the SCR reactor is blocked. It is possible to prevent corrosion accordingly.

In addition, accordingly, the SCR reactor can be manufactured with a general pipe material instead of an expensive material, thereby reducing equipment cost.

1 is a view showing an example of a conventional exhaust system including an SCR reactor.
2 is a view showing an exhaust system according to the first embodiment of the present invention.
3 is a view showing an exhaust system according to a second embodiment of the present invention.
4 is a view showing an exhaust system according to a third embodiment of the present invention.

Hereinafter, embodiments of an exhaust system according to the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, by installing a separate blowing line or ventilation line in the SCR reactor, after stopping the operation of the SCR reactor, external air is forcibly blown by an air blower or by forced suction and discharge using a ventilation fan. By forcibly discharging the exhaust gas remaining inside the SCR reactor, the generation of sulfuric acid due to the residual exhaust gas inside the SCR reactor and the resulting internal corrosion are prevented.

2 shows an exhaust system according to a first embodiment of the present invention.

As shown in Figure 2, the exhaust system according to the present invention, the SCR inlet line 20 connected and extended in the middle of the exhaust pipe 10 connected to the exhaust side of the engine 2, and the SCR inlet line 20 The SCR reactor 30 to be installed, the exhaust passage opening and closing valve 12 installed in the exhaust pipe 10 on the downstream side of the connection point of the SCR inlet line 20, and the exhaust passage opening and closing by extending from the outlet of the SCR reactor 30 The SCR outlet line 40 connected to the exhaust pipe 10 on the downstream side of the valve 12, the first SCR opening/closing valve 22 installed in the SCR inlet line 20, and the SCR outlet line 40 It includes a second SCR on-off valve 42.

As shown in Fig. 2, when the turbocharger 6 is installed in the first exhaust pipe 20 extending from the exhaust side of the engine 2, the SCR outlet line 40 is the exhaust passage opening/closing valve 12 It is connected to the exhaust pipe 10 on the inlet side (upstream side) of the turbocharger 6 while being a downstream side.

Accordingly, by selectively opening and closing the exhaust passage opening/closing valve 12 or the first and second SCR opening/closing valves 22, 42, the exhaust gas from the engine 2 passes through the SCR reactor 30, thereby reducing nitrogen oxides in the exhaust gas. It is discharged after removing or is discharged through the exhaust pipe 10 and the turbocharger 6 without passing through the SCR reactor (30).

Here, the turbocharger 6 includes a turbine 6a that rotates by flow energy of exhaust gas passing through the exhaust pipe 10 and a compressor 6b that compresses air by rotation of the turbine 6a.

In the present invention, an air blower 50 for blowing separate air for blowing into the SCR reactor 30 is installed, and the air blown from the air blower 50 is blown into the SCR reactor 30, 30) A blowing line 54 for forcibly discharging exhaust gas remaining therein is installed, and a blowing line opening/closing valve 52 is installed in the blowing line 54.

The engine 10 shown in FIG. 2 is shown by setting a two-stroke engine as an example, but this is only an example, and the present invention is not necessarily applied to a two-stroke engine, and the same applies to a four-stroke engine. .

In the embodiment shown in Fig. 2, an exhaust system in which an exhaust gas receiver 4 is installed upstream of the first exhaust pipe 20 is shown. The exhaust gas receiver 4 is connected to an exhaust manifold 10 connected to the cylinder head of the engine 2.

This shows the case of a two-stroke diesel engine as an example, and naturally there is also an exhaust system in which the exhaust pipe 10 is connected to the exhaust manifold without the exhaust gas receiver 4. Therefore, it should be understood that the exhaust gas receiver 4 is included in the exhaust pipe 10.

In the exhaust system of the present invention made as described above, when it is necessary to remove nitrogen oxides in exhaust gas through the SCR reactor 30, the exhaust passage opening and closing valve 12 is closed, and the first and second SCR opening and closing valves 22 and 42 ) Opens.

Then, the exhaust gas from the engine 2 passes through the SCR reactor 30 and reacts with the reducing agent by the catalyst inside the SCR reactor 30 to remove nitrogen oxides in the exhaust gas, and then comes out to the SCR outlet line 40. It enters the exhaust pipe 10 on the downstream side of the exhaust passage opening/closing valve 12, and then passes through the turbocharger 6 and is discharged to the outside.

When the SCR system is not used (when it is not necessary to remove nitrogen oxides in the exhaust gas), the exhaust passage opening/closing valve 12 is opened, and the first and second SCR opening/closing valves 22 and 42 are closed.

Then, the exhaust gas from the engine 2 cannot enter the SCR reactor 30 and enters the turbocharger 6 through the exhaust pipe 10 and is then discharged to the outside.

When the SCR system is to be stopped while using the SCR system, the closed on/off valve 12 is opened, the first SCR on/off valve 22 is closed, and the second SCR on/off valve 42 is open. While maintaining it as it is, the air blower 50 is operated and the blowing line opening/closing valve 52 is opened.

Then, the exhaust gas from the engine 2 cannot enter the SCR reactor 30 and enters the turbocharger 6 through the exhaust pipe 10, and the external air blown from the air blower 50 inside the SCR reactor 30 Is introduced into the SCR reactor 30 through the blowing line 54 to forcibly blow out residual exhaust gas. The residual exhaust gas blown out of the SCR reactor enters the exhaust pipe 10 through the SCR outlet line 40, joins the exhaust gas flowing through the exhaust pipe 10, and enters the turbocharger 6.

When the time for the exhaust gas remaining in the SCR reactor 30 to be completely removed, the operation of the air blower 50 is stopped, and the second SCR on-off valve 42 and the blowing line on-off valve 52 are closed, and the SCR reactor ( 30) is sealed.

When the SCR system is stopped while using the SCR system, it is forcibly removed through the air blower 50 to prevent the generation of sulfuric acid due to residual exhaust gas and internal corrosion in the SCR reactor 30.

3 shows an exhaust system according to a second embodiment of the present invention.

In the second embodiment shown in FIG. 3, as a line for discharging blown air from the SCR reactor 30 in the first embodiment, an external or exhaust pipe is formed by forming a separate discharge line without using the SCR outlet line 40. It is configured to discharge to (10).

That is, the first connection line 61 or separately extends from the SCR outlet line 40 or from the outlet side of the SCR reactor 30, or the second connection line 63 extends separately. A first line on/off valve 62 is installed on the first connection line 61, and a second line on/off valve 64 is installed on the second connection line 63.

Therefore, when the first connection line 61 is installed, the exhaust gas-containing blown air blown from the air blower 50 and discharged together with the residual exhaust gas inside the SCR reactor 30 flows through the first connection line 61. It is sent to the exhaust pipe 10 through and joins the exhaust gas passing through the exhaust pipe 10.

In addition, when the second connection line 63 is installed instead of the first connection line 61, the blown air containing exhaust gas that is blown from the air blower 50 and comes out together with the residual exhaust gas inside the SCR reactor 30 Is sent to the exhaust pipe 10 on the inlet side of the turbocharger 6 through the second connection line 63, joins the exhaust gas passing through the exhaust pipe 10, passes through the turbocharger 6, and is discharged to the outside.

In addition, instead of the first connection line 61 or the second connection line 63, a separate external discharge line 65 may be configured from the SCR outlet line 40 or from the outlet side of the SCR reactor 30. have. An external line opening/closing valve 66 is installed in the external discharge line 65. In this case, the blown air containing exhaust gas that is blown from the air blower 50 and comes out together with the residual exhaust gas inside the SCR reactor 30 is immediately discharged to the outside through the external discharge line 65.

4 is a diagram showing an exhaust system according to a third embodiment of the present invention.

The embodiment shown in FIG. 4 is an embodiment in which exhaust gas remaining in the SCR reactor 30 is forcibly sucked and discharged through the ventilation fan 120.

That is, the external air inlet line 100 and the inlet line opening/closing valve 102 are separately installed at the inlet side of the SCR reactor 30 in order to introduce air for blowing into the SCR reactor 30. Along with that, a residual gas discharge line 110 is separately configured from the SCR reactor 30 on the opposite side of the external air inlet line 100 and a discharge line opening/closing valve 111 is installed, and the residual gas discharge line 110 Install a ventilating fan 120.

When the SCR system is to be stopped while using the SCR system, the first and second SCR opening and closing valves 22 and 42 installed in the SCR inlet line 20 and the SCR outlet line 40 at the front and rear of the SCR reactor 30 Close all.

Along with that, the inlet line on/off valve 102 and the discharge line on/off valve 111 are opened and the ventilation fan 120 is operated.

Then, external air is sucked from the external air inlet line 100 by the drive of the ventilation fan 120, enters the SCR reactor 30, and is sucked into the ventilation fan 120 together with the remaining exhaust gas and discharged.

Instead of directly discharging the outlet of the ventilating fan 120 to the outside, it may be sent to the exhaust pipe 10 to be combined with the exhaust gas discharged from the engine to be discharged. In this case, as shown in FIG. 4, the outlet of the ventilation fan 120 is not extended to the outside, but is extended to the extension line 130 to be connected to the exhaust pipe 10 on the downstream side of the exhaust passage opening/closing valve 12 Can be employed.

Here, the extension line 130 is configured in the form of an extension line 131 connected to the exhaust pipe 10 on the downstream side of the turbocharger 6, joins the exhaust gas passing through the turbocharger 6 and discharges it to the outside. You can do it.

In contrast, the extension line 130 is configured in the form of an extension line 132 connected to the exhaust pipe 10 on the upstream side of the turbocharger 6 while being downstream of the exhaust passage opening/closing valve 12, and the inlet of the turbocharger 6 It is possible to join the exhaust gas at and enter the turbocharger 6.

In the above, specific preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the above-described embodiments, and any person having ordinary knowledge in the technical field to which the present invention pertains without departing from the gist of the present invention claimed in the claims will be able to implement various modifications.

2: engine
4: exhaust gas receiver
6: turbocharger
6a: turbine
6b: compressor
10: exhaust pipe
12: exhaust passage opening and closing valve
20: SCR inlet line
22: the first SCR on-off valve
30: SCR reactor
40: SCR exit line
42: 2nd SCR on-off valve
50: air blower
52: ventilation line opening/closing valve
54: blowing line
61: first connection line
62: first line on-off valve
63: second connection line
64: second line on-off valve
65: external discharge line
66: external line on/off valve
100: external air inlet line
102: inlet line opening/closing valve
110: residual gas discharge line
111: discharge line opening and closing valve
120: ventilation fan
130, 131, 132: extension line

Claims (6)

An SCR inlet line 20 connected and extended in the middle of the exhaust pipe 10 connected to the exhaust side of the engine 2;
SCR reactor 30 installed in the SCR inlet line 20;
An exhaust passage opening/closing valve 12 installed in the exhaust pipe 10 on the downstream side of the connection point of the SCR inlet line 20;
An SCR outlet line 40 extending from the outlet of the SCR reactor 30 and connected to the exhaust pipe 10 downstream of the exhaust passage opening/closing valve 12;
A first SCR on-off valve (22) installed in the SCR inlet line (20) and a second SCR on-off valve (42) installed in the SCR outlet line (40);
An air blower 50 for blowing air for blowing;
A blowing line 54 for forcibly discharging exhaust gas remaining in the SCR reactor 30 by blowing air blown from the air blower 50 into the SCR reactor 30; And
Exhaust system capable of preventing corrosion of the SCR reactor, characterized in that it comprises a blow line opening and closing valve (52) installed in the blowing line (54). The method of claim 1,
Ventilation containing exhaust gas exiting the SCR reactor 30 by being connected to the exhaust pipe 10 on the downstream side of the exhaust passage opening and closing valve 12 by extending separately from the SCR outlet line 40 or from the outlet side of the SCR reactor 30 A first connection line 61 for sending and discharging air to the exhaust pipe 10; And
An exhaust system capable of preventing corrosion of the SCR reactor, further comprising a first line on/off valve 62 for opening and closing the first connection line 61. The method of claim 1,
It extends separately from the SCR outlet line 40 or from the outlet side of the SCR reactor 30 and is connected to the exhaust pipe 10 between the exhaust passage opening/closing valve 12 and the turbocharger 6, thereby controlling the SCR reactor 30. A second connection line 63 for discharging the blown air containing the residual exhaust gas coming out to the exhaust pipe 10 to the inlet side of the turbocharger 6; And
An exhaust system capable of preventing corrosion of the SCR reactor, further comprising a second line on/off valve (64) for opening and closing the second connection line (63). The method of claim 1,
An external discharge line 65 for discharging the blown air to the outside by extending separately from the SCR outlet line 40 or from the outlet side of the SCR reactor 30;
An exhaust system capable of preventing corrosion of the SCR reactor, characterized in that it further comprises an external line opening/closing valve (66) installed in the external discharge line (65). An SCR inlet line 20 connected and extended in the middle of the exhaust pipe 10 connected to the exhaust side of the engine 2;
SCR reactor 30 installed in the SCR inlet line 20;
An exhaust passage opening/closing valve 12 installed in the exhaust pipe 10 on the downstream side of the connection point of the SCR inlet line 20;
An SCR outlet line 40 extending from the outlet of the SCR reactor 30 and connected to the exhaust pipe 10 downstream of the exhaust passage opening/closing valve 12;
A first SCR on-off valve (22) installed in the SCR inlet line (20) and a second SCR on-off valve (42) installed in the SCR outlet line (40);
An external air inlet line 100 and an inlet line opening/closing valve 102 that are separately installed at the inlet side of the SCR reactor 30 to introduce air for blowing into the SCR reactor 30;
A residual gas discharge line 110 that extends separately from the SCR reactor 30 on the opposite side of the external air inlet line 100;
It includes a ventilating fan 120 installed in the residual gas discharge line 110 to suck external air from the external air inlet line 100 and discharge it to the outside together with the exhaust gas remaining in the SCR reactor 30 Exhaust system that can prevent corrosion of SCR reactor characterized by. The method of claim 5,
The outlet of the ventilation fan 120 is connected to the exhaust pipe 10 on the downstream side of the exhaust passage opening/closing valve 12 through an extension line 130 to discharge exhaust gas-containing exhaust air from the SCR reactor 30 to the exhaust pipe ( An exhaust system capable of preventing corrosion of the SCR reactor, characterized in that discharged to 10).

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