KR102402304B1 - Power plant with selective catalytic reuction system - Google Patents

Abstract

The present invention relates to a power unit including a selective catalytic reduction system, and the power unit including a selective catalytic reduction system according to an embodiment of the present invention comprises an engine for discharging exhaust gas containing nitrogen oxides (NOx), and the engine An exhaust passage through which the exhaust gas is moved, a reactor installed on the exhaust passage and having a catalyst installed therein, a branch passage branched from the exhaust passage in front of the reactor and connected to the reactor, and the exhaust passage and the branch a bypass passage branching from the exhaust passage in front of the branch point of the passage and joining the exhaust passage in the rear of the reactor, the exhaust passage between the branching point of the exhaust passage and the bypass passage and the front end of the reactor; a circulation passage connecting the exhaust passage between the junction of the exhaust passage and the bypass passage and the rear end of the reactor, a first heating device installed on the branch passage, and a second heating device installed on the circulation passage include

Description

POWER PLANT WITH SELECTIVE CATALYTIC REUCTION SYSTEM

The present invention relates to a power unit including a selective catalytic reduction system for reducing nitrogen oxides contained in exhaust gas using a selective catalytic reduction reaction.

In general, power devices used in ships, etc. include a diesel engine that generates power, a turbocharger that supplies scavenging air to the diesel engine, and a selective catalytic reduction that reduces nitrogen oxides contained in exhaust gas emitted from the diesel engine. (selective catalytic reduction, SCR) systems, and the like.

In the selective catalytic reduction system, the exhaust gas and the reducing agent pass together through a reactor in which the catalyst is installed, and the nitrogen oxides and the reducing agent contained in the exhaust gas are reacted to reduce the nitrogen and water vapor.

When this selective catalytic reduction system is used in ships, its performance and operation are required so that the emission of nitrogen oxides (NOx) emitted from marine diesel engines can satisfy the International Air Pollution Prevention Third Regulation (IMO Tier-III). is becoming

In addition, the selective catalytic reduction system mainly uses a high-temperature active catalyst having an activation temperature within the range of 250 degrees Celsius to 350 degrees Celsius in consideration of economic efficiency and radiation regulation. Here, the activation temperature refers to a temperature at which the catalyst can stably reduce nitrogen oxides without being poisoned.

However, when the catalyst reacts outside the activation temperature range, the catalyst is poisoned and the activity of the catalyst is continuously reduced. In particular, when exhaust gas having a relatively low temperature of less than 250 degrees Celsius is introduced into a reactor in which a high-temperature active catalyst is installed, sulfur oxides (SOx) in the exhaust gas and ammonia (NH ₄ ) as a reducing agent react to generate catalyst poisoning substances do. The catalyst poisoning material may include at least one of ammonium sulfate ((NH4) ₂ SO ₄ ) and ammonium bisulfate (NH ₄ HSO ₄ ).

These catalyst poisoning substances are adsorbed to the catalyst, thereby reducing the activity of the catalyst. Therefore, in order to increase the efficiency of the catalyst and to minimize the loss due to maintenance, it is required to maintain the temperature of the catalyst within the active temperature range.

However, in the case of a low-speed diesel engine for a ship, the exhaust gas emission varies according to the change in the load of the diesel engine, and the climatic environment in which the ship is operating also affects the selective catalytic reduction reaction, so it is difficult to completely avoid catalyst poisoning. There is this.

An embodiment of the present invention provides a power unit having a selective catalytic reduction system capable of effectively regenerating a poisoned catalyst.

According to an embodiment of the present invention, a power unit including a selective catalytic reduction system includes an engine for discharging an exhaust gas containing nitrogen oxides (NOx), an exhaust flow path through which the exhaust gas discharged from the engine moves, and the exhaust flow path a reactor installed on the top and a catalyst installed therein; a branch flow path branched from the exhaust flow path in front of the reactor and connected to the reactor; a bypass flow path confluent with the exhaust flow path at the rear, the exhaust flow path between a branch point between the exhaust flow path and the bypass flow path, and a front end of the reactor, and a junction point between the exhaust flow path and the bypass flow path and the reactor and a circulation passage connecting the exhaust passage between rear ends, a first heating device installed on the branch passage, and a second heating device installed on the circulation passage.

The power unit including the selective catalytic reduction system is a closed loop (closed loop) including a post-treatment mode in which the exhaust gas of the engine moves through the reactor along the exhaust flow path, and the second heating device and the reactor A first catalyst regeneration mode to regenerate the catalyst of the reactor by circulating the fluid heated by the second heating device from the front end to the rear end of the reactor, and a lung including the second heating device and the reactor Form a loop (closed loop) and circulate the fluid heated by the second heating device from the rear end to the front end of the reactor to regenerate the catalyst of the reactor to operate in any one mode of the second catalyst regeneration mode have.

In the first catalyst regeneration mode and the second catalyst regeneration mode, the exhaust gas of the engine may bypass the reactor and move along the bypass flow path.

The closed loop formed in the first catalyst regeneration mode and the second catalyst regeneration mode includes a part of the exhaust passage and the circulation passage, and is formed to circulate between the reactor and the second heating device. can

The power unit including the selective catalytic reduction system includes a main valve installed in the exhaust passage between a junction of the exhaust passage and the branch passage and a connection point between the exhaust passage and the circulation passage, the exhaust passage and the bypass It may further include an auxiliary valve installed in the exhaust passage between the confluence of the passage and the rear end of the reactor, one or more circulation valves installed on the circulation passage, and a bypass valve installed on the bypass passage.

In the post-processing mode, the main valve and the auxiliary valve may be opened and the bypass valve and the circulation valve may be closed. In the first catalyst regeneration mode and the second catalyst regeneration mode, the bypass valve and the circulation valve may be opened, the main valve may be closed, and the auxiliary valve may be closed or only partially open.

The power unit including the selective catalytic reduction system includes a first blower installed on the branch passage and operated in the post-treatment mode, and installed on the circulation passage to heat the heated fluid in the first catalyst regeneration mode. A second blower may be further included to circulate from the front end to the rear end of the reactor and circulate the heated fluid from the rear end to the front end of the reactor in the second catalyst regeneration mode.

The power unit including the selective catalytic reduction system may further include an outdoor air supply unit connected to the circulation passage to supply outdoor air to the second heating device.

In addition, the power unit including the selective catalytic reduction system may further include a decomposition chamber installed on the branch passage, and a reducing agent supply unit for supplying a reducing agent to the decomposition chamber.

The first heating device may be operated when the temperature of the decomposition chamber is less than or equal to the reducing agent generation temperature in the post-processing mode.

According to an embodiment of the present invention, the power unit including the selective catalytic reduction system can effectively regenerate the poisoned catalyst.

1 is a block diagram of a power unit including a selective catalytic reduction system according to an embodiment of the present invention.
2 to 5 are diagrams showing the operating state of the power unit including the selective catalytic reduction system of FIG. 1 .

Hereinafter, with reference to the accompanying drawings, the embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

It is noted that the drawings are schematic and not drawn to scale. Relative dimensions and proportions of parts in the drawings are shown exaggerated or reduced in size for clarity and convenience in the drawings, and any dimensions are illustrative only and not limiting. In addition, the same reference numerals are used to indicate like features to the same structure, element, or part appearing in two or more drawings.

The embodiment of the present invention specifically represents an ideal embodiment of the present invention. As a result, various modifications of the diagram are expected. Accordingly, the embodiment is not limited to a specific shape of the illustrated area, and includes, for example, a shape modification by manufacturing.

Hereinafter, a power unit 101 including a selective catalytic reduction (SCR) system according to an embodiment of the present invention will be described with reference to FIG. 1 .

As shown in FIG. 1 , the power unit 101 including a selective catalytic reduction (SCR) system according to an embodiment of the present invention includes an engine 200 , an exhaust flow path 610 , and a reactor 300 . , a branch flow path 640 , a bypass flow path 620 , a circulation flow path 680 , a first heating device 410 , and a second heating device 420 .

In addition, the power unit 101 including a selective catalytic reduction system according to an embodiment of the present invention is a first blower 450 , a second blower 460 , an outdoor air supply unit 800 , a decomposition chamber 500 , a reducing agent supply unit 550 , a reducing agent injection unit 570 , and a supercharger 250 may be further included.

In addition, the power unit 101 including a selective catalytic reduction system according to an embodiment of the present invention further includes a main valve 710 , a bypass valve 720 , a circulation valve 780 , and an auxiliary valve 730 . can do.

The engine 200 may be used as a main power source for supplying propulsion to a ship or vehicle. As an example, the engine 210 may be a two-stroke low-speed diesel engine for ships. As the engine 200, various types of engines known to those of ordinary skill in the art may be used.

Also, in one embodiment of the present invention, the engine 200 discharges an exhaust gas containing nitrogen oxides (NOx).

The supercharger 250 is connected to the exhaust port of the engine 200 and rotates the turbine at the pressure of the exhaust gas of the engine 200 to compress and supply new external air to the engine 200 . Accordingly, the engine 200 equipped with the supercharger 250 has improved efficiency. However, the supercharger 250 may be omitted if necessary, and may be installed in various positions as known to those of ordinary skill in the art.

In one embodiment of the present invention, the exhaust gas discharged by the engine 200 has a temperature within the range of 250 degrees Celsius to 500 degrees Celsius, and the temperature of the exhaust gas may be lowered through the supercharger 250 . For example, the exhaust gas passing through the supercharger 250 may have a temperature of 150 degrees Celsius or more and lower than 250 degrees Celsius.

The exhaust passage 610 is connected to the exhaust port of the engine 200 to discharge the exhaust gas of the engine 200 . When the supercharger 250 is mounted, the exhaust flow path 610 may sequentially connect the engine 200, the supercharger 250, and the reactor 300 to be described later. That is, the exhaust gas of the engine 200 moves along the exhaust passage 610 . As such, the exhaust flow path 610 supplies the exhaust gas of the engine 200 to the reactor 300 .

The reactor 300 is installed on the exhaust passage 610 . The reactor 300 includes a catalyst 350 for reducing nitrogen oxides (NOx) contained in the exhaust gas discharged from the engine 200 . The catalyst 350 promotes a reaction between nitrogen oxides (NOx) and a reducing agent contained in exhaust gas to reduce nitrogen oxides (NOx) into nitrogen and water vapor.

In addition, in one embodiment of the present invention, the catalyst 350 installed inside the reactor 300 may be arranged in a multi-layered structure based on the movement direction of the exhaust gas. That is, the catalyst 350 may be provided in the form of a plurality of catalyst modules, and the plurality of catalyst modules may be disposed along the movement direction of the exhaust gas.

The catalyst 350 may be made of various materials known to those skilled in the art, such as zeolite, vanadium, and platinum. For example, the catalyst 350 may have an activation temperature within the range of 250 degrees Celsius to 350 degrees Celsius. Here, the activation temperature refers to a temperature at which the catalyst 350 can stably reduce nitrogen oxides without being poisoned. When the catalyst 350 reacts outside the active temperature range, the catalyst 350 is poisoned and the efficiency is lowered.

For example, when a reduction reaction to reduce nitrogen oxides contained in exhaust gas occurs at a relatively low temperature of 150 degrees Celsius or more and less than 250 degrees Celsius, sulfur oxides (SOx) and ammonia (NH ₃ ) in the exhaust gas react Thus, a catalyst poisoning substance is produced.

Specifically, the poisoning material that poisons the catalyst 350 may include at least one of ammonium sulfate ((NH ₄ ) ₂ SO ₄ ) and ammonium bisulfate (NH ₄ HSO ₄ ). This catalyst poisoning material is adsorbed to the catalyst 350 to reduce the activity of the catalyst 350 . Since the catalyst poisoning material is decomposed at a relatively high temperature, that is, at a temperature within the range of 350 degrees Celsius to 450 degrees Celsius, the catalyst 350 in the reactor 300 may be heated to regenerate the poisoned catalyst 350 .

As the reducing agent, ammonia (NH ₃ ) or urea (urea, CO(NH ₂ ) ₂ ) may be used. When urea is used as a reducing agent, urea (urea, CO(NH ₂ ) ₂ ) is hydrolyzed or pyrolyzed to produce ammonia (NH ₃ ) and isocyanic acid (HNCO). And isocyanic acid (HNCO) is again decomposed into ammonia (NH ₃ ) and carbon dioxide (CO ₂ ). That is, urea is decomposed to finally produce ammonia. And ammonia (NH ₃ ) serves as a final reducing agent that directly reacts with nitrogen oxides.

Also, the housing of the reactor 300 may be made of, for example, stainless steel having excellent heat resistance.

The branch flow path 640 branches from the exhaust flow path 610 in front of the reactor 300 and is connected to the reactor 300 . A portion of the exhaust gas branched from the exhaust passage 610 and moving along the branch passage 640 may be used for decomposition generation of the reducing agent in the decomposition chamber 500 to be described later.

At this time, the connection of the reactor 300 and the branch flow path 640 is indirectly connected by the branch flow path 640 rejoining the exhaust flow path 610 in front of the reactor 300 or the branch flow path 640 is the reactor 300 . can be directly connected with

In addition, in this specification, the front means the upstream side based on the flow of exhaust gas, and the rear means the downstream side.

The first heating device 410 is installed on the branch flow path 640 . When the first heating device 410 is operated, the fluid flowing through the branch flow path 640, that is, a branched portion of the exhaust gas discharged from the engine 200 is heated to increase the temperature. For example, the first heating device 410 may be an oil burner or a plasma burner.

And in one embodiment of the present invention, the heat energy supplied by the first heating device 410 may be used to generate the decomposition of the reducing agent.

The first blower 450 may be installed on the branch flow path 640 , like the first heating device 410 . The first blower 450 may control the flow rate and flow velocity of the fluid moving along the branch flow path 640 .

The decomposition chamber 500 is installed on the branch flow path 640 . The decomposition chamber 500 receives urea (urea, CO(NH ₂ ) ₂ ), which is a reducing agent precursor, and decomposes it to generate ammonia (NH ₃ ) used as a reducing agent to reduce nitrogen oxides (NOx).

Specifically, when the temperature in the decomposition chamber 500 is maintained within the range of 300 degrees Celsius to 500 degrees Celsius, urea (urea, CO(NH ₂ ) ₂ ) is easily hydrolyzed while ammonia (NH ₃ ) and isocyanic acid ( Isocyanic acid (HNCO) is formed. And isocyanic acid (HNCO) is again decomposed into ammonia (NH ₃ ) and carbon dioxide (CO ₂ ). That is, when urea is decomposed, ammonia may be finally produced.

The reducing agent injection unit 570 receives ammonia (NH ₃ ) generated in the decomposition chamber 500 and injects it into the exhaust gas to be introduced into the reactor 300 . Ammonia injected through the reducing agent injection unit 570 is mixed with the exhaust gas and passes through the catalyst 350 of the reactor 300 to reduce nitrogen oxides contained in the exhaust gas. For example, the reducing agent injection unit 570 may be installed at the junction of the branch flow path 640 and the exhaust flow path, that is, the exhaust flow path 610 in front of the reactor 300 . In addition, the reducing agent injection unit 570 may be installed at the front end of the reactor 300 .

The reducing agent supply unit 550 supplies urea, which is a reducing agent precursor, to the decomposition chamber 500 . The reducing agent supply unit 550 may supply an appropriate amount of urea to the decomposition chamber 500 in consideration of the reducing agent demand varying according to the load of the engine 200 .

The reducing agent supply unit 550 may include various configurations known to those skilled in the art, such as a storage tank, a compressed air supply device for spraying, and the like.

The bypass flow path 620 is branched from the exhaust flow path 610 in front of the reactor 300 and merges with the exhaust flow path 610 at the rear side of the reactor 300 . The bypass valve 720 is installed on the bypass flow path 620 to open and close the bypass flow path 620 .

The circulation passage 680 is an exhaust passage 610 between the branch point of the exhaust passage 610 and the bypass passage 620 and the front end of the reactor 300 , and the exhaust passage 610 and the bypass passage 620 . An exhaust flow path 610 between the confluence point and the rear end of the reactor 300 is connected.

One or more circulation valves 780 are installed on the circulation passage 680 . In one embodiment of the present invention, the circulation valve 780 includes a first circulation valve 781 installed relatively adjacent to the front end of the reactor 300 and a second circulation valve 782 installed relatively adjacent to the rear end of the reactor 300 . ) may be included.

The second heating device 420 is installed on the circulation passage 680 . When the second heating device 420 is operated, a portion of the fluid flowing through the circulation passage 680 is heated to increase the temperature. In one embodiment of the present invention, the heat energy supplied by the second heating device 420 may be used to regenerate the catalyst 350 installed in the reactor 300 . As such, when the catalyst 350 is to be regenerated, a part of the exhaust flow path 610 and the circulation flow path 680 are included and a closed loop is circulated between the reactor 300 and the second heating device 420 . ) is formed.

For example, the second heating device 420 , like the first heating device 410 , may be an oil burner or a plasma burner. That is, in one embodiment of the present invention, oxygen may be required for operation of the first heating device 410 and the second heating device 420 .

In particular, according to an embodiment of the present invention, since the second heating device 420 operates where the closed loop is formed, combustion air may become insufficient when the second heating device 420 is continuously operated.

The outdoor air supply unit 800 may be connected to the circulation passage 680 to supply outdoor air to the second heating device 420 . That is, the outdoor air supply unit 800 may supply outdoor air to the circulation passage 680 to supply oxygen required for the operation of the second heating device 420 operated in a closed loop environment.

For example, the outdoor air supply unit 800 may include an outdoor air supply passage 810 for injecting external air and an outdoor air supply valve 870 for opening and closing the outdoor air supply passage 810 .

As such, in one embodiment of the present invention, when a burner requiring combustion air is used as the second heating device 420 , the second heating device 420 used in a closed loop environment is provided from the outside air supply unit 800 . Since oxygen can be supplied, effective operation of the second heating device 420 is possible.

The second blower 460 is installed on the circulation passage 680 similarly to the second heating device 420 . The second blower 460 may control the movement direction and flow velocity of the fluid moving along the circulation passage 680 . That is, the second blower 460 may circulate the fluid heated by the second heating device 420 from the front end to the rear end direction of the reactor 300 or may circulate it from the rear end of the reactor 300 to the front end direction.

The main valve 710 is installed in the exhaust passage 610 between the junction of the exhaust passage 610 and the branch passage 640 and the connection point of the exhaust passage 610 and the circulation passage 680 . The auxiliary valve 730 is installed in the exhaust passage 610 between the junction of the exhaust passage 610 and the bypass passage 620 and the rear end of the reactor 300 . That is, the main valve 710 and the auxiliary valve 730 are respectively installed in front and rear of the reactor 300 to open and close the exhaust flow path 610 .

When the main valve 710 and the auxiliary valve 730 are closed and the circulation valve 780 is opened, the reactor 300 and the second heating device ( A closed loop formed to circulate between 420 may be formed.

With this configuration, the power unit 101 including the selective catalytic reduction system according to an embodiment of the present invention can effectively regenerate the poisoned catalyst 350 .

That is, the power unit 101 including the selective catalytic reduction system has a separate and independent circulation flow path 680 for catalyst regeneration in order to regenerate the catalyst 350 . In addition, by forming a closed loop that can circulate between the reactor 300 and the second heating device 420 using the circulation flow path 680 , thermal energy consumed to regenerate the catalyst 350 can be minimized. In addition, the time required to increase the temperature of the catalyst 350 can be shortened.

Also, according to an embodiment of the present invention, the exhaust gas of the engine 200 may move through the bypass flow path 620 and be discharged even during the operation of regenerating the catalyst 350 by forming a closed loop.

That is, the ship equipped with the power unit 101 including the selective catalytic reduction system according to an embodiment of the present invention can regenerate the catalyst 350 during operation without stopping or stopping the operation.

In addition, according to an embodiment of the present invention, the flow of the fluid circulating in the closed loop, that is, the moving direction of the fluid can be selectively adjusted. Therefore, regeneration of the catalyst 350 installed in the reactor 300 can be effectively performed.

Specifically, when it is desired to preferentially regenerate the catalyst 350 disposed at the front end of the reactor 300 , the second blower 460 transfers the fluid heated by the second heating device 420 from the front end to the rear end of the reactor 300 . move in the direction And when it is desired to preferentially regenerate the catalyst 350 disposed at the rear end of the reactor 300, the second blower 460 transfers the fluid heated by the second heating device 420 from the rear end of the reactor 300 to the front end. move

As described above, according to an embodiment of the present invention, it is possible to preferentially regenerate the highly poisoned catalyst 350 among the catalysts 350 disposed at the front and rear ends of the reactor 300 .

Hereinafter, the operating principle of the power unit 101 including a selective catalytic reduction system according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3 .

The power unit 101 including the selective catalytic reduction system according to an embodiment of the present invention may operate separately in any one of the post-treatment mode, the first catalyst regeneration mode, and the second catalyst regeneration mode.

As shown in FIG. 1 , in the post-treatment mode, the exhaust gas of the engine 200 may move through the reactor 300 along the exhaust flow path 610 . That is, in the post-processing mode, the exhaust gas of the engine 200 may be post-processed and purified. Here, purification means reducing nitrogen oxides contained in exhaust gas.

Specifically, in the post-processing mode, the main valve 710 and the auxiliary valve 730 may be opened and the bypass valve 720 and the circulation valve 780 may be closed.

In addition, the first heating device 410 may be operated when the temperature of the decomposition chamber 500 for generating the reducing agent in the post-processing mode is less than or equal to the temperature at which the reducing agent can be generated. And the second heating device 420 is not operated. At this time, the reducing agent decomposed in the decomposition chamber 500 may move together with the fluid and may be injected into the exhaust passage 610 in front of the reactor 300 or the front end of the reactor 300 through the reducing agent injection unit 570 .

As shown in FIG. 2 , the second heating device 420 may be operated in the first catalyst regeneration mode. And the first heating device 410 is not operated. The bypass valve 720 and the circulation valve 780 are opened and the main valve 710 and the auxiliary valve 730 are closed to form a closed loop including the second heating device 420 and the reactor 300 . can form. In this case, only a part of the auxiliary valve 730 may be opened if necessary. And the second blower 460 regenerates the catalyst 350 of the reactor 300 by circulating the fluid heated by the second heating device 420 from the front end to the rear end of the reactor 300 in a closed loop. can do it

In addition, the exhaust gas of the engine 200 may be discharged by moving through the bypass flow path 620 .

As described above, the catalyst 350 is poisoned by a catalyst poisoning material generated by reacting sulfur oxide (SOx) and ammonia (NH ₃ ) in the exhaust gas, so that the activity may be reduced. For example, a catalyst poisoning material such as ammonium sulfate ((NH ₄ ) ₂ SO ₄ ) and ammonium bisulfate (NH ₄ HSO ₄ ) is decomposed at a temperature within the range of 350 degrees Celsius to 450 degrees Celsius. Accordingly, when the catalyst 350 in the reactor 300 is heated, the catalyst poisoning material is removed to restore the activity of the catalyst 350 .

As such, the closed loop formed in the first catalyst regeneration mode includes a part of the exhaust passage 610 and the circulation passage 680 , and circulates between the reactor 300 and the second heating device 420 . Since the second heating device 420 heats the fluid circulating in the closed loop, thermal energy consumed to regenerate the catalyst 350 can be minimized, thereby preventing fuel wastage.

In particular, the first catalyst regeneration mode according to an embodiment of the present invention may be operated when preferentially regenerating the catalyst 350 disposed in front of the reactor 300 .

In addition, as shown in FIG. 3 , when oxygen in the closed loop is insufficient due to the operation of the second heating device 420 , the external air supply unit 800 is operated to supply the combustion air required for the second heating device 420 . can

As such, when the outdoor air supply unit 800 continuously supplies outdoor air to the closed loop in order to supply combustion air to the second heating device 420 , the pressure of the closed loop may increase.

In this case, the auxiliary valve 730 may be partially opened to maintain the pressure of the closed loop within a safe range. Here, the safe range means within an allowable pressure at which the exhaust system and the selective catalytic reduction system can be stably maintained.

As shown in FIG. 4 , the second heating device 420 may be operated even in the second catalyst regeneration mode. And the bypass valve 720 and the circulation valve 780 are opened, and the main valve 710 and the auxiliary valve 730 are closed, so that the closed loop including the second heating device 420 and the reactor 300 is closed. ) can be formed. In this case, only a part of the auxiliary valve 730 may be opened if necessary. However, in the second catalyst regeneration mode, the second blower 460 circulates the fluid heated by the second heating device 420 from the rear end to the front end of the reactor 300 in a closed loop to circulate the catalyst 350 of the reactor 300 . can be played back.

The exhaust gas of the engine 200 may be discharged by moving through the bypass flow path 620 .

As described above, the closed loop formed in the second catalyst regeneration mode includes a part of the exhaust passage 610 and the circulation passage 680 , and circulates between the reactor 300 and the second heating device 420 . Since the second heating device 420 heats the fluid circulating in the closed loop, thermal energy consumed to regenerate the catalyst 350 can be minimized, thereby preventing fuel wastage.

In particular, the second catalyst regeneration mode according to an embodiment of the present invention may be operated when preferentially regenerating the catalyst 350 disposed at the rear end of the reactor 300 .

In addition, as shown in FIG. 5 , when oxygen in the closed loop is insufficient due to the operation of the second heating device 420 , the external air supply unit 800 is operated to supply the combustion air required for the second heating device 420 . can

As such, when the outdoor air supply unit 800 continuously supplies outdoor air to the closed loop in order to supply combustion air to the second heating device 420 , the pressure of the closed loop may increase.

In this case, the auxiliary valve 730 may be partially opened to maintain the pressure of the closed loop within a safe range. Here, the safe range means within an allowable pressure at which the exhaust system and the selective catalytic reduction system can be stably maintained.

In addition, according to an embodiment of the present invention, the exhaust gas discharged from the engine 200 in the first catalyst regeneration mode and the second catalyst regeneration mode can bypass the reactor 300 and move along the bypass flow path 620 . have. That is, in the first catalyst regeneration mode, the exhaust gas of the engine 200 may be discharged without post-treatment.

On the other hand, an embodiment of the present invention is not limited to the above, and even if it is not in the first catalyst regeneration mode and the second catalyst regeneration mode, the ship operates in a non-polluting area or a non-environmental control area, or a selective catalytic reduction system In an emergency situation in which an abnormality has occurred but regeneration is impossible, the exhaust gas of the engine 200 may be discharged through the bypass flow path 620 . In this case, the first heating device 410 is not operated.

By this operation, the power unit 101 including the selective catalytic reduction system according to an embodiment of the present invention can effectively regenerate the poisoned catalyst 350 .

That is, the power unit 101 including the selective catalytic reduction system has a separate and independent circulation flow path 680 for catalyst regeneration in order to regenerate the catalyst 350 . In addition, by forming a closed loop that can circulate between the reactor 300 and the second heating device 420 using the circulation flow path 680 , thermal energy consumed to regenerate the catalyst 350 can be minimized. In addition, the time required to increase the temperature of the catalyst 350 can be shortened.

In addition, the vessel equipped with the power unit 101 including the selective catalytic reduction system according to an embodiment of the present invention can regenerate the catalyst 350 during operation without stopping or stopping the operation.

In addition, according to an embodiment of the present invention, it is possible to selectively control the flow of the fluid circulating in the closed loop, that is, the moving direction of the fluid. That is, it is possible to preferentially regenerate the catalyst 350 with a severe degree of poisoning among the catalysts 350 disposed at the front and rear ends of the reactor 300 . Therefore, regeneration of the catalyst 350 installed in the reactor 300 can be effectively performed.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential characteristics thereof. will be.

Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the following claims, the meaning and scope of the claims, and All changes or modifications derived from the equivalent concept should be construed as being included in the scope of the present invention.

101: Power unit with selective catalytic reduction system
200: engine
250: supercharger
300: reactor
350: catalyst
410: first heating device
420: second heating device
450: first blower
460: second blower
500: decomposition chamber
550: reducing agent supply unit
570: reducing agent injection unit
610: exhaust flow path
620: bypass euro
640: quarter euro
680: circulation flow path
710: main valve
720: bypass valve
730: auxiliary valve
780: circulation valve
781: first circulation valve
782: second circulation valve
800: outside air supply unit
810: outdoor air supply line
870: fresh air supply valve

Claims (10)

an engine that discharges exhaust gas containing nitrogen oxides (NOx);
an exhaust passage through which the exhaust gas discharged from the engine moves;
a reactor installed on the exhaust passage and having a catalyst installed therein;
a branch passage branched from the exhaust passage in front of the reactor and connected to the reactor;
a bypass passage branching from the exhaust passage in front of the branching point of the exhaust passage and the branch passage and joining the exhaust passage in the rear of the reactor;
a circulation passage connecting the exhaust passage between the branch point of the exhaust passage and the bypass passage and the front end of the reactor, and the exhaust passage between the merging point of the exhaust passage and the bypass passage and the rear end of the reactor;
a first heating device installed on the branch passage; and
A second heating device installed on the circulation passage
includes,
a post-treatment mode in which the exhaust gas of the engine moves through the reactor along the exhaust passage;
A first to form a closed loop including the second heating device and the reactor and circulate the fluid heated by the second heating device from the front end to the rear end of the reactor to regenerate the catalyst of the reactor catalyst regeneration mode; and
A second to form a closed loop including the second heating device and the reactor and circulate the fluid heated by the second heating device from the rear end to the front end of the reactor to regenerate the catalyst of the reactor Catalyst regeneration mode
A power plant comprising a selective catalytic reduction system operating in either mode. According to claim 1,
In the first catalyst regeneration mode and the second catalyst regeneration mode, the exhaust gas of the engine bypasses the reactor along the bypass flow path and moves to a power unit including a selective catalytic reduction system. According to claim 1,
The closed loop formed in the first catalyst regeneration mode and the second catalyst regeneration mode includes a part of the exhaust passage and the circulation passage, and is formed to circulate between the reactor and the second heating device Power unit with selective catalytic reduction system. According to claim 1,
a main valve installed in the exhaust passage between a junction of the exhaust passage and the branch passage and a connection point between the exhaust passage and the circulation passage;
an auxiliary valve installed in the exhaust passage between the junction of the exhaust passage and the bypass passage and the rear end of the reactor;
one or more circulation valves installed on the circulation passage; and
a bypass valve installed on the bypass flow path
Power unit including a selective catalytic reduction system further comprising a. 5. The method of claim 4,
In the after-treatment mode, the main valve and the auxiliary valve are open and the bypass valve and the circulation valve are closed,
In the first catalyst regeneration mode and the second catalyst regeneration mode, the bypass valve and the circulation valve are open, the main valve is closed, and the auxiliary valve is closed or partially open. According to claim 1,
a first blower installed on the branch flow path and operated in the post-processing mode;
installed on the circulation passage to circulate the heated fluid from the front end to the rear end of the reactor in the first catalyst regeneration mode, and circulate the heated fluid from the rear end to the front end of the reactor in the second catalyst regeneration mode Shiki's 2nd blower
Power unit including a selective catalytic reduction system further comprising a. According to claim 1,
Power unit including a selective catalytic reduction system further comprising an outdoor air supply unit connected to the circulation passage for supplying outdoor air to the second heating device. 8. The method according to any one of claims 1 to 7,
a decomposition chamber installed on the branch passage;
A reducing agent supply unit for supplying a reducing agent to the decomposition chamber
Power unit including a selective catalytic reduction system further comprising a. 9. The method of claim 8,
The first heating device is a power unit including a selective catalytic reduction system that is operated when the temperature of the decomposition chamber is less than or equal to the reducing agent generation temperature in the post-treatment mode.
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