KR20190036772A - Selective catalytic reduction system - Google Patents

Abstract

A selective catalytic reduction system according to an embodiment of the present invention is a selective catalytic reduction system purifying exhaust gas which is discharged by an engine, comprising: a main pipe through which exhaust gas passes; a first reactor installed on the main pipe, and having a first catalyst therein reducing nitrogen oxide contained in the exhaust gas; a second reactor installed at the back of the first reactor, and having a second catalyst reducing ammonia or carbon monoxide contained in the exhaust gas which passed through the first reactor; and a sub pipe guiding the exhaust gas which passed through the first reactor to pass by detouring to the second reactor.

Description

{SELECTIVE CATALYTIC REDUCTION SYSTEM}

An embodiment of the present invention relates to a selective catalytic reduction system, and more particularly, to a selective catalytic reduction system for selectively reducing nitrogen oxides contained in an exhaust gas.

Generally, the selective catalytic reduction system selectively reduces the nitrogen oxides contained in the exhaust gas. Specifically, the selective catalytic reduction system injects a reducing agent into the exhaust gas, passes through the mixed exhaust gas, and decomposes the nitrogen oxide into nitrogen or water (or water vapor) to be discharged to the outside.

The concentration of nitrogen oxides contained in the exhaust gas to the outside is required to meet international standards, and the concentration of nitrogen oxides contained in the exhaust gas should be reduced according to the regulations.

However, excessive use of the reducing agent or deteriorated reducing agent remains in the exhaust gas, which has a detrimental effect on the human body when it is discharged to the outside. That is, when the high concentration of ammonia is discharged in a state containing the exhaust gas, there is a problem that the reducing agent remaining in the exhaust gas with reduced nitrogen oxide has harmful effects on the human body.

An embodiment of the present invention relates to a selective catalytic reduction system capable of reducing nitrogen oxide contained in exhaust gas as well as undissolved reducing agent or carbon monoxide contained in exhaust gas among the reducing agent injected for its removal, .

According to an embodiment of the present invention, a selective catalytic reduction system for purifying exhaust gas exhausted from an engine includes a main pipe through which exhaust gas passes, and a main pipe disposed on the main pipe, for reducing nitrogen oxides contained in the exhaust gas A first reactor in which a first catalyst is disposed and a second reactor installed in a rear of the first reactor and configured to reduce ammonia or carbon monoxide contained in exhaust gas passing through the first reactor; And a sub-pipe for guiding the exhaust gas passed through the reactor to pass through the second reactor.

The selective catalytic reduction system may further include a controller for selectively moving the exhaust gas passing through the first reactor to the second reactor or the sub-pipe according to the amount of ammonia contained in the exhaust gas passing through the first reactor, As shown in FIG.

The selective catalytic reduction system may further include a front detection member installed on a main pipe behind the first reactor and transmitting information on exhaust gas passed through the first reactor to the control unit.

The selective catalytic reduction system may include a circulation pipe branching from the main pipe behind the first reactor and joining the main pipe in front of the first reactor, a heat supply member for supplying thermal energy to the circulation pipe, And a reducing agent decomposition chamber disposed on the pipe and thermally decomposing the reducing agent by heat energy supplied from the heat supply member.

In addition, the selective catalytic reduction system may further include a heat supply pipe for guiding thermal energy supplied from the heat supply member to the second catalyst.

The selective catalytic reduction system may further include a rear detecting member installed on a main pipe behind the second reactor and detecting information of exhaust gas passing through the second reactor.

The control unit may determine whether or not the second catalyst is regenerated in accordance with the information detected by the rear detection member, and when the second catalyst is regenerated, the thermal energy supplied from the heat supply member flows through the heat supply pipe The second catalyst may be supplied.

The selective catalytic reduction system may further include a first valve disposed downstream of the first reactor, a sub-valve disposed on the sub-pipe, and a second valve disposed downstream of the second reactor, When the information detected by the front detecting member is larger than the predetermined amount of ammonia, the first valve and the second valve may be opened and the sub valve may be closed.

The selective catalytic reduction system may further include a fourth valve disposed in the heat supply pipe, wherein the control unit closes the sub valve during regeneration of the second catalyst, and the second valve and the fourth valve Lt; / RTI >

The selective catalytic reduction system may include a bypass pipe for bypassing the first reactor and guiding the exhaust gas to pass therethrough, a bypass valve installed on the bypass pipe, and a third valve disposed on the main pipe in front of the first reactor. Further comprising a valve, wherein the control unit determines whether or not the selective catalytic reduction operation is performed, and closes the bypass valve and opens the third valve when a selective catalytic reduction operation is required.

The selective catalytic reduction system may further include an economizer disposed on the main pipeline behind the second reactor to recover thermal energy contained in the exhaust gas.

According to embodiments of the present invention, the selective catalytic reduction system can reduce the nitrogen oxide contained in the exhaust gas as well as the undissolved reducing agent or the carbon monoxide contained in the exhaust gas among the reducing agent injected for its removal, have.

Figures 1 to 3 illustrate the operation of a selective catalytic reduction system in accordance with one embodiment of the present invention.
Figures 4-6 illustrate operation of a selective catalytic reduction system in accordance with another embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

The drawings are schematic and illustrate that they are not drawn to scale. The relative dimensions and ratios of the parts in the figures are shown exaggerated or reduced in size for clarity and convenience in the figures, and any dimensions are merely illustrative and not restrictive. And to the same structural elements or parts appearing in more than one drawing, the same reference numerals are used to denote similar features.

The embodiments of the present invention specifically illustrate ideal embodiments of the present invention. As a result, various variations of the illustration are expected. Thus, the embodiment is not limited to any particular form of the depicted area, but includes modifications of the form, for example, by manufacture.

Hereinafter, a selective catalytic reduction system 101 according to an embodiment of the present invention will be described with reference to FIG.

Selective catalytic reduction system (101) purifies the exhaust gas discharged by engine (10). Specifically, the selective catalytic reduction system 101 reduces nitrogen oxides contained in the exhaust gas discharged from the engine 10 and discharges them to the outside.

1, the selective catalytic reduction system 101 includes a first reactor 200 in which a main pipe 100 and a first catalyst 210 are installed, and a second reactor 200 in which a second catalyst 410 is installed, A reactor 400 and a sub-pipe 500.

The main pipe 100 passes through the exhaust gas. Specifically, the main piping 100 is connected to an engine 10 that generates power by burning fuel. Therefore, the exhaust gas discharged from the engine 10 and containing nitrogen oxide passes through the main pipe 100.

The first reactor 200 is installed on the main piping 100. Also, a first catalyst 210 is installed in the first reactor 200. The first catalyst 210 may be a catalyst for selectively reducing the nitrogen oxide contained in the exhaust gas. Accordingly, the exhaust gas containing nitrogen oxide flows into the first reactor 200 along the main pipe 100, and the nitrogen oxide is reduced after passing through the first reactor 200, so that the exhaust gas can be discharged to the outside.

For example, the first catalyst 210 may be a selective reduction catalyst.

A second reactor (400) is installed behind the first reactor (200). In addition, a second catalyst 410 is installed in the second reactor 400. The second catalyst 410 can reduce ammonia (NH3) or carbon monoxide (CO) contained in the exhaust gas. Specifically, the second reactor 400 may be installed on the main piping 100 in the rear of the first reactor 200.

For example, the second catalyst 410 may be a selective catalytic oxidation catalyst. This selective oxidation catalyst (SCO) can oxidize ammonia to nitrogen, convert carbon monoxide to carbon dioxide, and discharge it. That is, the selective oxidation catalyst (SCO) can reduce the concentration of ammonia and the concentration of carbon monoxide contained in the exhaust gas to be discharged.

The sub-pipe 500 guides the exhaust gas passing through the first reactor 200 to pass through the second reactor 400. In addition, the exhaust gas passing through the sub-pipe 500 may be exhaust gas that has passed through the first reactor 200.

Therefore, the selective catalytic reduction system 101 according to an embodiment of the present invention can effectively reduce ammonia or carbon monoxide contained in the exhaust gas as well as nitrogen oxides contained in the exhaust gas to be discharged to the outside.

In addition, the selective catalytic reduction system 101 according to an embodiment of the present invention may further include a control unit 900.

The controller 900 controls the amount of ammonia contained in the exhaust gas passing through the first reactor 200 so that the exhaust gas having passed through the first reactor 200 is supplied to the second reactor 400 or the sub- ). ≪ / RTI >

The control unit 900 determines the amount (concentration) of ammonia contained in the exhaust gas that has passed through the first reactor 200. Accordingly, the control unit 900 may move the exhaust gas, which has passed through the first reactor 200, to the second reactor 400 based on the predetermined amount of ammonia information, The gas can be transferred to the sub-pipe 500.

Therefore, the exhaust gas having passed through the first reactor 200 and reduced by nitrogen oxide is discharged to the outside through the sub-pipe 500 by the control unit 900, or the nitrogen oxide is reduced through the first reactor 200 The exhaust gas passes through the second reactor 400 to reduce ammonia or carbon monoxide and can be discharged to the outside.

In addition, the selective catalytic reduction system 101 according to an embodiment of the present invention may further include a front detection member 110.

The front detecting member 110 may be installed on the main pipe 100 at the rear of the first reactor 200. Further, the front detecting member 110 may detect the information of the exhaust gas that has passed through the first reactor 200, and may transmit the detected information to the controller 900. Specifically, the front detecting member 110 can detect the amount (concentration) of ammonia contained in the exhaust gas that has passed through the first reactor 200, the temperature of the exhaust gas, the pressure of the exhaust gas, and the like.

For example, the front detecting member 110 detects information including the amount (concentration) of ammonia in the exhaust gas passing through the first reactor 200 and the main pipe 100 in the rear of the first reactor 200 can do.

Alternatively, the front detecting member 110 may include a plurality of sensors for detecting the concentration of nitrogen oxide, the amount (concentration) of ammonia, the temperature of the exhaust gas, and the pressure of the exhaust gas.

Therefore, the control unit 900 compares the amount of ammonia set in advance with the amount of ammonia in the exhaust gas detected by the front detecting member 110. If the amount of ammonia contained in the exhaust gas that has passed through the first reactor 200 detected by the front detecting member 110 is greater than the predetermined amount of ammonia, the controller 900 passes through the first reactor 200 It is judged that the undifferentiated reducing agent remaining in the current exhaust gas is discharged with exceeding the setting range. At this time, when the non-decomposed reducing agent passes through the first reactor 200 and is discharged with the set amount exceeding the set range, the control unit 900 controls the exhaust gas passing through the first reactor 200 to flow into the second reactor 400 So as to guide the inflow.

That is, when the undifferentiated reducing agent is discharged with the excess amount of the undissolved reducing agent exceeding the set range, the exhaust gas having passed through the first reactor 200 flows into the second reactor 400, And ammonia can be oxidized and converted to nitrogen to be discharged. Therefore, the second catalyst 410 is non-decomposed, and the ammonia remaining in the exhaust gas is discharged to the outside, so that the second catalyst 410 can be oxidized and discharged safely to the outside so that there is no harmful influence on the human body.

Alternatively, when the amount of ammonia contained in the exhaust gas passing through the first reactor 200 detected by the front detecting member 110 is smaller than the predetermined amount of ammonia, the current exhaust gas passing through the first reactor 200 It is judged that the undifferentiated reducing agent remaining in the gas is discharged to the set range. At this time, when the undifferentiated reducing agent is discharged to the set range through the first reactor 200, the control unit 900 guides the exhaust gas passing through the first reactor 200 to the sub-pipe 500 .

For example, the predetermined amount of ammonia may be a value set by international regulations or a value of a harmless concentration to the human body.

In addition, the selective catalytic reduction system 101 according to an embodiment of the present invention may further include a reducing agent supply unit 700.

The reducing agent supply unit 700 may include a circulation pipe 710, a heat supply member 720, and a reducing agent decomposition chamber 730. The reducing agent supply unit 700 may supply the pyrolyzed reducing agent to the main pipe 100 in front of the first reactor 200.

The circulation pipe 710 branches from the main pipe 100 at the rear of the first reactor 200 and merges with the main pipe 100 at the front of the first reactor 200. Specifically, the circulation pipe 710 can guide the exhaust gas passing through the first reactor 200 and at least a part of the exhaust gas having the reduced nitrogen oxide introduced therein to be fed to the front of the first reactor 200. That is, one side of the circulation pipe 710 is connected to the main pipe 100 on the rear side of the first reactor 200 and the other side of the circulation pipe 710 is connected to the main pipe 100 on the front side of the first reactor 200 . In addition, an AIG (Ammonia Injection Grid) for injecting the pyrolyzed reducing agent may be installed at the other side of the circulation pipe 710.

The heat supply member 720 can supply heat energy to the circulation pipe 710. Specifically, the heat supply member 720 may be installed on the circulation pipe 710. For example, the heat supplying member 720 may be any one of a burner, a heater, and a hot wire.

The heat supply member 720 may further include a circulation member such as a blower that can circulate the exhaust gas flowing into the circulation pipe 710.

Alternatively, the heat supply member 720 can supply thermal energy obtained from an external heat source to the circulation pipe 710. Specifically, the heat supply member 720 can supply hot air supplied from the outside to the circulation pipe 710. [

The reducing agent decomposition chamber 730 may be disposed on the circulation pipe. In addition, the reducing agent decomposition chamber 730 can cause the reducing agent to be thermally decomposed by the heat energy supplied from the heat supply member 720. Specifically, unillustrated Urea is supplied into the reducing agent decomposition chamber 730, and this urea can be pyrolyzed by thermal energy supplied from the heat supply member 720 to generate ammonia.

Accordingly, the reducing agent supply unit 700 may inject the generated ammonia into the main pipe 100 in front of the first reactor 200 to allow the ammonia mixed with the exhaust gas to flow into the first reactor 200.

The reducing agent supply unit 700 may further include an outside air supply line 740 for supplying outside air for combustion of the heat supplying member 720. The outside air supply line 740 is disposed on the circulation pipe 710 in front of the heat supply member 720 so that fresh air or compressed air for smooth combustion of fuel such as a burner can be introduced. In addition, when the outside air flows into the circulation pipe 710, the exhaust gas passing through the circulation pipe 710 and the pyrolyzed reducing agent can be smoothly moved.

Specifically, the supply of outside air introduced through the outside air supply line 740 may be controlled by the controller 900 depending on whether the heat supply member 720 is operated or not.

Therefore, the reducing agent supply unit 700 can effectively utilize the exhaust gas passing through the first reactor 200 to pyrolyze the urea.

The selective catalytic reduction system 101 according to an embodiment of the present invention may further include a first valve 650, a sub valve 640, and a second valve 620.

The first valve (650) may be installed behind the first reactor (200). Specifically, the first valve 650 may be installed on the main pipe 100 at the rear of the first reactor 200. The first valve 650 may be controlled by the control unit 900. Specifically, the first valve 650 opens or closes the main piping 100 in front of the second reactor 400 so that the exhaust gas passing through the first reactor 200 is introduced into or blocked from the second reactor 400. .

The sub-valve 640 may be installed on the sub-pipe 500. Further, the sub-valve 640 can be controlled by the control unit 900. Specifically, the sub-valve 640 may open or close the sub-pipe 500 so that the exhaust gas passing through the first reactor 200 is introduced into or blocked from the sub-pipe 500.

The second valve 620 may be installed behind the second reactor 400. Specifically, the second valve 620 may be installed on the main pipe 100 at the rear of the second reactor 400. And the second valve 620 may be controlled by the control unit 900.

The control unit 900 opens the first valve 650 and the second valve 620 and closes the sub valve 640 when the information detected by the front detecting member 110 is larger than the preset amount of ammonia, The exhaust gas passing through the first reactor 200 may be introduced into the second reactor 400.

In other words, when the control unit 900 determines that the amount of ammonia that has been finely divided into the present exhaust gas passing through the first reactor 200 remains on the basis of the predetermined amount of ammonia and the information detected by the front detecting member 110, The first valve 650 and the second valve 620 may be opened and the sub valve 640 may be closed so as to oxidize and discharge the remaining ammonia included in the exhaust gas.

In addition, the selective catalytic reduction system 101 according to an embodiment of the present invention may further include a bypass pipe 300, a bypass valve 630, and a third valve 610.

The bypass pipe 300 can guide the exhaust gas to pass through the first reactor 200 to pass through. Also, the bypass pipe 300 can guide the exhaust gas discharged from the engine 10 to bypass the first reactor 200 to be discharged to the outside.

The bypass valve 630 may be installed on the bypass pipe 300. The bypass valve 630 may also be controlled by the controller 900 to regulate the flow of exhaust gas through the bypass pipe 300.

The third valve 610 may be installed on the main pipe 100 in front of the first reactor 200. The third valve 610 may control the flow of the exhaust gas flowing into the first reactor 200 by the control unit 900.

The bypass pipe 300 is connected to the engine 10 and the third valve 610 and the other end is connected to the main pipe 100 on the other side of the sub pipe 500 or on the rear side of the second valve 620. [ Lt; / RTI > One side of the sub pipe 500 is connected to the main pipe 100 between the one side of the circulation pipe 710 and the first valve 650 and the other side of the sub pipe 500 is connected to the side of the bypass pipe 300 End or the main piping 100, respectively.

For example, the engine 10 may be a marine engine. Therefore, the control unit 900 of the selective catalytic reduction system 101 determines an exhaust gas emission control area (ECA) or an exhaust gas emission control non-regulated area (Non-ECA) based on the position information of the ship or predetermined flight information .

Accordingly, the control unit 900 can determine the presence or absence of the selective catalytic reduction operation (SCR) according to the position information or the operation information on which the selective catalytic reduction system 101 is mounted. Specifically, the control unit 900 operates the reducing agent supply unit 700 in the exhaust gas emission control region to reduce the nitrogen oxide contained in the exhaust gas and discharge the exhaust gas to the outside. Alternatively, the control unit 900 may stop the operation of the reducing agent supply unit 700 in the exhaust gas emission control area and exhaust the exhaust gas to the outside through the first reactor 200.

Specifically, when the control unit 900 performs the selective catalytic reduction operation (SCR), the bypass valve 630 may be closed and the third valve 610 may be opened. At this time, the controller 900 operates the reducing agent supply unit 700 to inject ammonia generated by the urea pyrolyzed in the front of the first reactor 200.

Alternatively, the controller 900 may open the bypass valve 630 and close the third valve 610 when operating the exhaust gas emission control area without performing the selective catalytic reduction operation (SCR).

In addition, the selective catalytic reduction system 101 according to an embodiment of the present invention may further include an economizer 600.

The economizer 600 may be installed on the main pipe 100 behind the second valve 620. In addition, the economizer 600 can recover thermal energy of the exhaust gas discharged to the outside through the main pipe 100 and utilize it in another configuration such as a boiler installed in a ship equipped with the selective catalytic reduction system 101.

Therefore, the selective catalytic reduction system 101 according to an embodiment of the present invention not only decomposes nitrogen oxide contained in exhaust gas but also decomposes residual ammonia contained in the exhaust gas to convert it into nitrogen and discharge it to the outside have.

In addition, the selective catalytic reduction system 102 according to another embodiment of the present invention may further include a heat supply pipe 800 as shown in FIG. The selective catalytic reduction system 102 according to another embodiment of the present invention includes a main pipe 100 and a first reactor 200 and a second reactor 400 included in the selective catalytic reduction system 101, The first valve 650, the second valve 620, the third valve 610, the sub-valve 640, and the bypass pipe 640, the sub-pipe 500, the front detecting member 110, the reducing agent supply unit 700, 300, a bypass valve 630, an economizer 600, and a controller 900.

The heat supply pipe 800 can guide the heat energy supplied from the heat supply member 720 to the second catalyst 410. Specifically, one end of the heat supply pipe 800 is connected to the circulation pipe 710 between the heat supply member 720 or the heat supply member 720 and the reducing agent decomposition chamber 730, and the end of the heat supply pipe 800 And the other end may be connected to the main pipe 100 or the second reactor 400 between the first valve 650 and the second reactor 400.

The heat supplying member 720 can guide the thermal energy supplied from the heat supplying member 720 to be supplied to the second catalyst 410 and regenerate the second catalyst 410. [ Specifically, the heat supplying member 720 supplies heat energy to the second catalyst 410 to remove foreign substances such as soot adsorbed on the second catalyst 410. That is, when the efficiency of the second catalyst 410 deteriorates due to the adsorption of soot or foreign matter, the heat supplying member 720 can remove the soot or the foreign substance absorbed by supplying the thermal energy to the second catalyst 410.

At this time, the heat energy supplied by the heat supplying member 720 can inject a fluid having a high temperature of 400 ° C (degrees Celsius) or more.

In addition, the selective catalytic reduction system 102 according to another embodiment of the present invention may further include a rear detection member 120.

The rear detecting member 120 can detect the information of the exhaust gas passing through the second reactor 400. [ Further, the rear detecting member 120 may be installed on the main pipe 100 in the rear of the second reactor 400. The rear detecting member 120 may detect the information of the exhaust gas passing through the second reactor 400 and transmit the information to the controller 900.

That is, the rear detecting member 120 may be installed on the main pipe 100 between the second reactor 400 and the second valve 620.

For example, the rear detecting member 120 may detect at least one of the amount (concentration), temperature, and pressure of ammonia contained in the exhaust gas that has passed through the second reactor 400. Specifically, the rear detecting member 120 may detect information that can determine the regeneration point of the second catalyst 410 installed in the second reactor 400.

Alternatively, the rear detecting member 120 may include a plurality of sensors for detecting the concentration of nitrogen oxide, the amount (concentration) of ammonia, the temperature of the exhaust gas, and the pressure of the exhaust gas.

The control unit 900 of the selective catalytic reduction system 102 according to another embodiment of the present invention may control the regeneration of the second catalyst 410 according to the information detected by the rear detection member 120 and the front detection member 110. [ Or not.

When the front detecting member 110 detects the ammonia amount A of the exhaust gas that has passed through the first reactor 200, the controller 900 determines that the rear detecting member 120 has passed through the second reactor 400 The difference between the amount of ammonia B of the exhaust gas and the amount of ammonia detected by the aforementioned front detecting member 110 is calculated. The control unit 900 may determine that regeneration of the second catalyst 410 is necessary when the difference B-A between the amounts of ammonia is equal to or greater than a predetermined value. At this time, the controller 900 can determine that the ammonia is still oxidized and can not be decomposed into nitrogen but can be discharged to the outside.

Alternatively, the controller 900 may determine that regeneration of the second catalyst 410 is necessary when the rear detecting member 120 detects a predetermined ammonia amount or more.

Accordingly, when it is determined that the regeneration of the second catalyst 410 is necessary, the control unit 900 controls the supply of heat energy supplied from the heat supply member 720 to the second catalyst 410 through the heat supply pipe 800 .

The control unit 900 can determine the regeneration completion time of the second catalyst 410 according to the information of the exhaust gas detected by the rear detecting member 120 during the regeneration of the second catalyst 410. That is, the controller 900 can determine the regeneration completion time of the second catalyst 410 based on the catalyst regeneration completion value (the exhaust gas pressure and temperature) preset in the controller 900 and the like.

Or when the front detecting member 110 detects the exhaust gas pressure P1 that has passed through the first reactor 200, the controller 900 determines that the rear detecting member 120 has passed through the second reactor 400 The pressure difference P2 of one exhaust gas and the pressure difference of the exhaust gas detected by the aforementioned front detecting member 110 are calculated. The control unit 900 may determine that regeneration of the second catalyst 410 is necessary when the difference B-A of the exhaust gas pressures is equal to or greater than a predetermined value.

Alternatively, the control unit 900 may determine that regeneration of the second catalyst 410 is necessary when the rear detecting member 120 detects a predetermined exhaust gas pressure abnormality value.

That is, the control unit 900 can determine that regeneration of the second catalyst 410 is necessary by increasing back pressure in the second reactor 400 due to adsorption of soot or foreign matter on the second catalyst 410.

In addition, the selective catalytic reduction system 102 according to another embodiment of the present invention may further include a fourth valve 660.

The fourth valve 660 may be installed on the heat supply pipe 800. In addition, the fourth valve 660 may be controlled by the control unit 900. The fourth valve 660 is opened by the control unit 900 and supplies thermal energy to the second catalyst 410 from the heat supply member 720 through the heat supply pipe 800 or is closed by the control unit 900 The heat supply pipe 800 can be closed so that the heat energy is prevented from being supplied to the second catalyst 410. [

The control unit 900 may close the sub valve 640 and open the second valve 620 and the fourth valve 660 when the second catalyst 410 is regenerated. At this time, heat energy from the heat supply member 720 can be supplied to the second catalyst 410 through the heat supply pipe 800 while the heat supply member 720 is in operation.

Therefore, the selective catalytic reduction system 102 according to another embodiment of the present invention can effectively utilize the thermal energy supplied from the heat supply member 720 for thermal decomposition of the reducing agent to the regeneration of the second catalyst 410.

Hereinafter, the operation of the selective catalytic reduction system 101 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG.

Fig. 1 shows a case where a ship equipped with the selective selective catalytic reduction system 101 passes through an exhaust gas emission control area. The passage information of the exhaust gas emission control area can be determined from the route or position information of the ship set in the control unit 900.

At this time, the control unit 900 stops the operation of the reducing agent supply unit 700, opens the detour valve 630, and opens the first valve 650, the second valve 620, the third valve 610, 640). Therefore, the exhaust gas containing nitrogen oxide discharged from the engine 10 can be discharged to the main pipe 100 at the rear of the second valve 620 through the bypass pipe 300. At this time, the heat energy can be recovered from the exhaust gas containing nitrogen oxide by the economizer 600 installed on the main pipe 100. And the recovered heat energy can be utilized in the boiler in the ship or in the heating system supplied in the ship.

FIG. 2 shows a case where a ship equipped with the selective selective catalytic reduction system 101 passes through an exhaust gas emission control area.

At this time, the control unit 900 closes the bypass valve 630, the first valve 650 and the second valve 620, opens the third valve 610 and the sub valve 640, and supplies the reducing agent supply unit 700 .

Exhaust gas containing nitrogen oxide discharged from the engine 10 flows into the first reactor 200 through the main pipe 100. A part of the exhaust gas that has passed through the first reactor 200 flows through the circulation pipe 710 and the urea Urea is supplied to the reducing agent decomposition chamber 730 by the heat energy supplied to the reducing agent decomposition chamber 730 according to the operation of the heat supply member 720 Ammonia and mixed into the main pipe 100 in front of the first reactor 200. Accordingly, the exhaust gas containing nitrogen oxide mixed with ammonia passes through the first reactor 200, the nitrogen oxide is decomposed into water and nitrogen, passes through the sub-pipe 500, and then flows to the main pipe 100 to the outside. At this time, the exhaust gas discharged to the outside through the main pipe 100 can be recovered by the economizer 600.

Further, the front detecting member 110 can detect the amount of ammonia contained in the exhaust gas that has passed through the first reactor 200. At this time, the controller 900 determines that the amount of ammonia in the first reactor 200 detected by the front detecting member 110 is less than a predetermined value. That is, FIG. 2 shows the selective catalytic reduction system 101 performing the selective catalytic reduction operation (SCR) when no ammonia slip (NH3-Slip) occurs.

3 is a view showing a case where a ship equipped with the selective selective catalytic reduction system 101 passes through an exhaust gas emission control area and ammonia slip occurs.

2, when the amount of ammonia in the first reactor 200 detected by the front detecting member 110 is larger than the predetermined amount of ammonia, the controller 900 performs a differentiation It is determined that ammonia slip has occurred due to the presence of ammonia in the exhaust gas passing through the first reactor 200. At this time, the control unit 900 maintains the closed state of the bypass valve 630, maintains the opening of the third valve 610, and maintains the operation of the reducing agent supply unit 700. Also, the controller 900 closes the sub valve 640 and opens the first valve 650 and the second valve 620.

Therefore, the exhaust gas discharged from the engine 10 and containing nitrogen oxides passes through the reducing agent supply unit 700 and the first reactor 200, and the nitrogen oxides are reduced, and the exhaust gas containing the undissolved and remaining ammonia 2 reactor 400 and can be decomposed into nitrogen and discharged to the outside. Also, the carbon monoxide (CO) contained in the exhaust gas passing through the first reactor 200 may be oxidized and converted into carbon dioxide through the second reactor 400 and may be discharged to the outside. The exhaust gas containing nitrogen or carbon dioxide is discharged to the outside through the main pipe 100, and the heat energy can be recovered by the economizer 600.

Alternatively, when the amount of ammonia preset is larger than the amount of ammonia in the first reactor 200 detected by the front detecting member 110, the control unit 900 can control the state of FIG. 2 again.

FIG. 4 shows a case where a ship equipped with the selective selective catalytic reduction system 102 passes through the exhaust gas emission control area and supplies thermal energy to the second catalyst 410.

The control unit 900 may compare the amount or pressure of the ammonia detected by the rear detecting member 120 with the predetermined backward ammonia amount or predetermined back pressure. Therefore, the control unit 900 determines whether the amount of ammonia detected by the rear detecting member 120 is greater than the predetermined amount of the rear ammonia, or the pressure of the exhaust gas detected by the rear detecting member 120 is greater than the predetermined pressure It can be determined that the supply of the thermal energy of the second catalyst 410 is necessary. At this time, the efficiency of the second catalyst 410 is reduced and the control unit 900 can not effectively oxidize the exhaust gas passing through the first reactor 200, so that the carbon monoxide or ammonia contained therein can be discharged to the outside It can be judged. Therefore, in this case, the control unit 900 determines that the second catalyst 410 is regenerated by reducing the efficiency of the second catalyst 410 by adsorbing soot or foreign matter on the second catalyst 410 .

Alternatively, the controller 900 may compare the amount or pressure of ammonia detected by the front detecting member 110 with the amount or pressure of ammonia detected by the rear detecting member 120. Accordingly, the control unit 900 controls the regeneration operation of the second catalyst 410 based on the information of the exhaust gas that has passed through the first reactor 200 and the information of the exhaust gas that has passed through the second reactor 400 .

The control unit 900 closes the bypass valve 630 and the sub valve 640 and opens the first valve 650, the second valve 620, the third valve 610, and the fourth valve 660. At this time, the controller 900 is still operating the reducing agent supply unit 700. That is, the thermal energy from the heat supplying member 720 can be transferred to the second catalyst 410 as well as the reducing agent decomposition chamber 730 that pyrolyzes the urea Urea. At this time, the heat supplying member 720 can consume a large amount of fuel or supply a relatively large amount of heat energy compared with the case where only the reducing agent decomposing chamber 730 supplies heat energy.

Therefore, the high-temperature fluid containing the exhaust gas or heat energy that has passed through the second reactor 400 can be discharged to the outside through the main pipe 100 at the rear of the second reactor 400. At this time, the economizer 600 can recover the heat energy included in the exhaust gas passing through the main pipe 100 and the high-temperature fluid.

Thus, the second catalyst 410 can be effectively regenerated even when the selective catalyst reduction system 102 performs the selective catalytic reduction operation (SCR) while the ship passes through the exhaust gas emission control area.

5 shows a case where ammonia slip occurs during regeneration of the first catalyst 210 in a state where a ship equipped with the selective selective catalytic reduction system 102 is in an anchoring state.

The controller 900 determines whether or not the current vessel is berth from the operating state information of the engine 10 installed on the vessel. Also, the control unit 900 can determine whether the first catalyst 210 is regenerated from the preset period or the preset regeneration information. Specifically, the control unit 900 determines whether or not the pressure information detected by the front detecting member 110 detected during the SCR operation or the nitrogen oxide concentration of the exhaust gas that has passed through the first catalyst 210, Information or the predetermined first catalyst regeneration concentration information to determine whether the regeneration operation of the first catalyst 210 is necessary or not.

That is, when the pressure information of the exhaust gas detected by the front detecting member 110 is larger than the preset first catalyst regeneration pressure information, the controller 900 determines that regeneration of the first catalyst 210 is necessary. Alternatively, when the nitrogen oxide concentration detected by the front detecting member 110 is greater than the predetermined first catalyst regeneration concentration information, the control unit 900 determines that regeneration of the first catalyst 210 is necessary.

Therefore, the control unit 900 can regenerate the first catalyst 210 when the ship is at a berth. At this time, the control unit 900 operates only the heat supply member 720 in the reducing agent supply unit 700 and cuts off the supply of the reducing agent to the reducing agent decomposition chamber 730. The control unit 900 closes the bypass valve 630, the third valve 610, the fourth valve 660, and the sub valve 640. In addition, the controller 900 closes the first valve 650. That is, the fluid having high thermal energy is supplied to the first reactor 200.

If the amount of ammonia contained in the exhaust gas that has passed through the first reactor 200 detected by the front detecting member 110 is greater than the predetermined amount of ammonia, Decomposed ammonia in the exhaust gas passing through the circulation pipe 710 and the circulation pipe 710. Accordingly, the control unit 900 opens the first valve 650 and the second valve 620.

That is, exhaust gas containing ammonia and high-temperature thermal energy which have passed through the first reactor 200 pass through the second reactor 400 and then are discharged to the outside.

Therefore, even when the first catalyst 210 installed in the first reactor 200 is regenerated, the decomposed ammonia, carbon monoxide, etc. remaining in the first reactor 200 or the circulation pipe 710 are not oxidized And can be prevented from being discharged.

 FIG. 6 shows the second catalyst 410 when the ship equipped with the selective selective catalytic reduction system 102 is in the anchoring state.

The controller 900 determines whether or not the current vessel is berth from the operating state information of the engine 10 installed on the vessel.

The control unit 900 compares the preset second catalyst regeneration pressure based on the pressure information detected by the front detecting member 110 and the pressure information detected by the rear detecting member 120 so that the regeneration of the second catalyst 410 Can be determined.

Alternatively, the control unit 900 may determine that the second catalyst 410 has been poisoned when the pressure information detected by the rear detecting member 120 is greater than predetermined pressure information.

 When the pressure information detected by the rear detecting member 120 is larger than the preset second catalyst regeneration pressure information and the pressure information detected by the rear detecting member 120 is greater than the preset second catalyst regeneration pressure information, the controller 900 controls the first catalyst 210 and the second catalyst 410) judges that playback is necessary.

At this time, when the vessel is staying and regenerating the second catalyst 410, the controller 900 closes the first valve 650, the third valve 610, the sub-valve 640, and the bypass valve 630 The second valve 620 and the fourth valve 660 are opened. Then, only the heat supply member 720 in the reducing agent supply unit 700 is operated and the reducing agent supply to the reducing agent decomposition chamber 730 is interrupted.

Thus, heat energy from the heat supply member 720 is transferred to the second catalyst 410 through the heat supply pipe 800. The fluid having the high temperature thermal energy that has passed through the second catalyst 410 can be discharged to the outside through the main pipe 100 at the rear of the second valve 620. That is, the fluid having high temperature thermal energy passes through the second catalyst 410, and soot or foreign matter adsorbed on the second catalyst 410 may be burned or discharged to the outside.

At this time, the rear detecting member 120 may provide the controller 900 with information necessary for controlling the heat supplying member 720 so that the high temperature heat energy required for the regeneration of the second catalyst 410 is supplied. That is, the rear detecting member 120 may detect the temperature of the exhaust gas or the fluid passing through the main pipe 100 at the rear of the second catalyst 410 and provide the detected temperature to the controller 900.

If regeneration of both the first catalyst 210 and the second catalyst 410 is required, the controller 900 closes the third valve 610, the bypass valve 630 and the sub valve 640, The second valve 620 and the fourth valve 660 may be opened to operate only the heat supply member 720 in the reducing agent supply unit 700 and shut off the supply of the reducing agent to the reducing agent decomposition chamber 730. Accordingly, the first catalyst 210 and the second catalyst 410 can be supplied with a fluid having a high thermal energy to regenerate the first catalyst 210 and the second catalyst 410.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. will be.

It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, It is intended that all changes and modifications derived from the equivalent concept be included within the scope of the present invention.

10: engine 101, 102: selective catalytic reduction system
100: main pipe 110: front detecting member
120: rear detecting member 200: first reactor
210: first catalyst 300: bypass pipe
400: Second Reactor 420: Second Catalyst
500: Sub-pipe 600: Economizer
610: third valve 620: second valve
630: bypass valve 640: sub-valve
650: first valve 660: fourth valve
710: Circulating piping 720: Heat supply member
730: reducing agent decomposition chamber 800: heat supply piping

Claims (11)

A selective catalytic reduction system for purifying an exhaust gas emitted by an engine,
A main pipe through which exhaust gas passes;
A first reactor disposed on the main pipe and having a first catalyst disposed therein for reducing nitrogen oxides contained in the exhaust gas;
A second reactor disposed downstream of the first reactor and provided with a second catalyst for reducing ammonia or carbon monoxide contained in the exhaust gas passing through the first reactor; And
A sub-pipe for guiding the exhaust gas passing through the first reactor to pass through the second reactor,
≪ / RTI > The method of claim 1,
And a control unit for selectively moving the exhaust gas passing through the first reactor to the second reactor or the sub-pipe according to the amount of ammonia contained in the exhaust gas that has passed through the first reactor. 3. The method of claim 2,
Further comprising: a front detecting member installed on a main pipe behind the first reactor and transmitting information of exhaust gas passed through the first reactor to the control unit. 4. The method of claim 3,
A circulation pipe branching from a main pipe behind the first reactor and joining with a main pipe in front of the first reactor;
A heat supply member for supplying thermal energy to the circulation pipe; And
A reducing agent decomposition chamber disposed on the circulation pipe for thermally decomposing the reducing agent by thermal energy supplied from the heat supply member,
≪ / RTI > 5. The method of claim 4,
And a heat supply pipe for guiding heat energy supplied from the heat supply member to the second catalyst. The method of claim 5,
Further comprising: a rear detecting member installed on a main pipe behind the second reactor and detecting information of exhaust gas passing through the second reactor. The method of claim 6,
Wherein,
Wherein the control unit determines whether or not the second catalyst is regenerated according to the information detected by the rear detecting member, and when the second catalyst is regenerated, thermal energy supplied from the heat supplying member is supplied to the second catalyst through the heat supply pipe Wherein the selective catalytic reduction system comprises: 4. The method of claim 3,
A first valve disposed behind the first reactor;
A sub-valve disposed on the sub-pipe;
Further comprising a second valve disposed behind the second reactor,
Wherein,
And opens the first valve and the second valve to close the sub-valve when the information detected by the front detecting member is larger than a predetermined amount of ammonia. 9. The method of claim 8,
Further comprising a fourth valve installed in the heat supply pipe,
Wherein,
And when the second catalyst is regenerated, the sub valve is closed and the second valve and the fourth valve are opened. 3. The method of claim 2,
A bypass pipe for bypassing the first reactor and guiding the exhaust gas to pass therethrough;
A bypass valve installed on the bypass pipe; And
Further comprising a third valve disposed on a main piping in front of the first reactor,
Wherein,
Wherein the bypass valve is closed and the third valve is opened when the selective catalytic reduction operation is required. The method of claim 1,
Further comprising an economizer installed on the main pipeline behind the second reactor for recovering heat energy contained in the exhaust gas.

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