KR20130119591A - Power plant for ship with selective catalytic reuction system for internal combustion engine - Google Patents

Abstract

Embodiment of the present invention relates to a marine power unit including a selective catalytic reduction system, the marine power unit including a selective catalytic reduction system is installed on the engine, the main exhaust passage for exhausting the exhaust gas of the engine, and the main exhaust passage And a turbocharger bypassing the turbocharger, a supercharger installed on the main exhaust passage between the engine and the selective catalytic reduction reactor, a main valve installed on the main exhaust passage between the supercharger and the selective catalytic reduction reactor, and The first bypass flow path for supplying the exhaust gas before passing through to the selective catalytic reduction reactor, bypassing the selective catalytic reduction reactor to connect the main exhaust passage between the main valve and the supercharger and the main exhaust passage through the selective catalytic reduction reactor On the second bypass flow path and the second bypass flow path It includes an installed bypass valve.

Description

[0001] POWER PLANT FOR SHIP WITH SELECTIVE CATALYTIC REUCTION SYSTEM FOR INTERNAL COMBUSTION ENGINE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a marine power unit, and more particularly, to a marine power unit including a selective catalytic reduction system.

In general, marine power plants include low speed diesel engines and turbochargers. Selective catalytic reduction (SCR) systems are systems for reducing nitrogen oxides by purifying exhaust gases generated from engines.

The selective catalytic reduction system reacts the nitrogen oxides contained in the exhaust gas with the reducing agent while passing the exhaust gas and the reducing agent together in the reactor equipped with the catalyst, thereby reducing the nitrogen and the water vapor.

The selective catalytic reduction system uses ammonia (NH ₃ ) and urea as a reducing agent for reducing nitrogen oxides. Selective catalytic reduction systems also utilize high temperature catalysts, which generally have an active temperature range from 250 degrees Celsius to 400 degrees Celsius.

On the other hand, when the temperature of the exhaust gas purified by the selective catalytic reduction system is lowered to 250 degrees Celsius or less, the catalyst activity is continuously lowered due to catalyst poisoning and infiltration of solids by sulfur components contained in the diesel engine fuel. There is this.

Embodiments of the present invention provide a marine power plant including a selective catalytic reduction system capable of effectively regenerating the poisoned catalyst as needed and improving the overall purification efficiency of the exhaust gas.

According to an embodiment of the present invention, a marine power unit including a selective catalytic reduction system includes an engine, a main exhaust passage for discharging exhaust gas of the engine, and a selective catalytic reduction installed on the main exhaust passage. a selective catalytic reduction (SCR) reactor, a turbo charger installed on the main exhaust flow path between the engine and the selective catalytic reduction reactor, and a main installed in the main exhaust flow path between the supercharger and the selective catalytic reduction reactor. A valve, a first bypass passage for bypassing the supercharger and supplying the exhaust gas before passing through the supercharger to the selective catalytic reduction reactor, and bypassing the selective catalytic reduction reactor to provide the gas between the main valve and the supercharger. The main via the main exhaust passage and the selective catalytic reduction reactor And a second bypass flow passage, and a bypass valve installed on the second bypass channel connecting the flow path group.

The ship's power plant including an optional catalytic reduction system can be selectively operated in one of the following modes: the main valve is open, the bypass valve is closed and the main valve is closed and the bypass valve is open. have.

In the regeneration mode, the exhaust gas having a relatively low temperature while passing through the supercharger may be blocked from flowing into the selective catalytic reduction reactor. The relatively high temperature exhaust gas generated in the engine may be directly introduced into the selective catalytic reduction reactor through the first bypass flow path to regenerate the catalyst.

The flow rate of the exhaust gas flowing into the selective catalytic reduction reactor through the first bypass passage may be in a range of 0.1% to 20% of the total exhaust gas generated in the engine.

And an auxiliary bypass valve installed on the first bypass flow path, wherein the auxiliary bypass valve may be opened and closed together with the bypass valve.

It may further include a reducing agent supply unit is installed in the main exhaust flow path for injecting a reducing agent to the exhaust gas before entering the selective catalytic reduction reactor.

The marine power plant including the selective catalytic reduction system may further include an auxiliary main valve installed on the main exhaust passage before passing through the selective catalytic reduction reactor and encountering the second bypass passage.

Bypassing the auxiliary main valve may further include a third bypass flow path connected to both ends of the main exhaust flow path.

The apparatus may further include a pressure control valve installed on the third bypass flow path.

When the auxiliary main valve is closed, the pressure regulating valve may be opened to allow the exhaust gas to pass in an amount less than or equal to the amount of the exhaust gas flowing into the selective catalytic reduction reactor through the first bypass flow path. .

According to embodiments of the present invention, a marine power plant including a selective catalytic reduction system can effectively regenerate the poisoned catalyst and improve the overall purification efficiency of the exhaust gas.

1 is a block diagram showing a normal mode of a ship power unit including a selective catalytic reduction system according to a first embodiment of the present invention.
2 is a block diagram showing a regeneration mode of a power plant for a ship including a selective catalytic reduction system according to a first embodiment of the present invention.
3 is a block diagram showing a normal mode of a ship power unit including a selective catalytic reduction system according to a second embodiment of the present invention.
4 is a block diagram showing a regeneration mode of a power unit for ship including a selective catalytic reduction system according to a second 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.

In addition, in the various embodiments, elements having the same configuration are represented by the same reference symbols in the first embodiment, and in the other second embodiment, only the configurations different from those of the first embodiment are described .

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 structure, element or component 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.

1 and 2, a ship power unit 101 including a selective catalytic reduction (SCR) system according to a first embodiment of the present invention will be described.

1 and 2, the ship power unit 101 including the selective catalytic reduction system according to the first embodiment of the present invention is an engine 10, a turbo charger 20, a selective catalyst A reduction reactor 30, a main exhaust flow path 581, a first bypass flow path 61, a second bypass flow path 62, a main valve 41, and a bypass valve 43.

In addition, the ship power unit 101 including the selective catalytic reduction system includes a reducing agent supply unit 37, an auxiliary main valve 42, a third bypass flow path 63, a pressure regulating valve 48, and an intake flow path 59. It may further include.

Engine 10 may be a low speed diesel engine, typically used in ships, and various engines known to those skilled in the art may be used. The turbo charger 20 supplies the fresh air to the engine 10 by turning the turbine to the pressure of the exhaust gas of the engine 10. At this time, the new outside air is supplied to the engine 10 through the intake passage 59.

On the other hand, the exhaust gas discharged from the engine 10 may have a temperature within a range of 250 degrees Celsius to 450 degrees Celsius. However, the temperature of the exhaust gas may be lowered to a temperature of 150 degrees Celsius or more and less than 250 degrees Celsius through the supercharger 20.

In addition, although not shown, the marine power unit 101 including a selective catalytic reduction system may further include an exhaust gas receiver and a scavenge air receiver. The exhaust receiver evenly relaxes the exhaust gas of the engine 10 discharged with an unbalanced pressure by the cylinder reciprocating motion of the engine 10. The scavenging receiver evenly alleviates the uneven pressure of the new outside air supplied by the supercharger 20 to the engine 10.

The selective catalytic reduction reactor 30 purifies the exhaust gas of the engine 10 to reduce nitrogen oxides contained in the exhaust gas. The selective catalytic reduction reactor 30 reacts the nitrogen oxide contained in the exhaust gas with a reducing agent to reduce the nitrogen and water vapor.

The selective catalytic reduction reactor (30) comprises a catalyst (35). Specifically, a catalyst 35 known to those skilled in the art, such as zeolite, vanadium, and platinum, is installed in the interior of the selective catalytic reduction reactor 30 through a catalyst carrier.

The main exhaust passage 51 is connected to the exhaust port of the engine 10 to exhaust the exhaust gas of the engine 10. In addition, the main exhaust passage 51 sequentially connects the engine 10, the supercharger 20, and the selective catalytic reduction reactor 30. That is, the supercharger 20 and the selective catalytic reduction reactor 30 are sequentially installed on the main exhaust flow path 51.

The main valve 41 is installed in the main exhaust flow path 51 between the supercharger 20 and the selective catalytic reduction reactor 30. That is, the main valve 41 introduces or blocks the exhaust gas passing through the supercharger 20 into the selective catalytic reduction reactor 30.

The first bypass flow passage 61 bypasses the supercharger 20 and supplies exhaust gas not passed through the supercharger 20 to the selective catalytic reduction reactor 30. Specifically, the first bypass flow passage 61 connects the main exhaust flow passage 51 between the main valve 41 and the selective catalytic reduction reactor 30 and the exhaust port of the engine 10. In addition, the first bypass flow passage 61 includes a main exhaust flow passage 51 between the main valve 41 and the selective catalytic reduction reactor 30, and a main exhaust flow passage 51 between the supercharger 20 and the engine 10. You can also connect

That is, the first bypass flow passage 61 may directly introduce a relatively high temperature exhaust gas not passing through the supercharger 20 directly into the selective catalytic reduction reactor 30. Exhaust gas introduced into the selective catalytic reduction reactor 30 through the first bypass passage 61 may have a temperature in the range of 250 degrees Celsius to 450 degrees Celsius.

In addition, the flow rate of the exhaust gas flowing into the selective catalytic reduction reactor 30 through the first bypass flow passage 61 is in the range of 0.1% to 20% of the total exhaust gas generated in the engine 10.

The second bypass flow path 62 bypasses the selective catalytic reduction reactor 30. Specifically, the second bypass flow passage 62 connects the main exhaust flow passage 51 between the main valve 41 and the supercharger 20 and the main exhaust flow passage 51 through the selective catalytic reduction reactor 30.

That is, when the main valve 41 is closed and the exhaust gas does not pass through the selective catalytic reduction reactor 30, the second bypass flow path 62 bypasses the exhaust gas and discharges it.

The bypass valve 43 is provided on the second bypass flow path 62. The bypass valve 43 is controlled to close when the main valve 41 is opened, and open when the main valve 41 is closed.

On the other hand, the bypass valve 43 is a second bypass valve provided at the rear end of the first bypass valve 431 and the second bypass flow path 62 provided at the front end of the second bypass flow path 62 ( 432).

The reducing agent supply unit 37 is installed in the main exhaust passage 51 to inject the reducing agent into the exhaust gas before flowing into the selective catalytic reduction reactor 30. The injected reducing agent is mixed with the exhaust gas and introduced into the selective catalytic reduction reactor 30. The reducing agent includes a variety of known reducing agent to practitioners in the art, such as ammonia (NH ₃₎ and urea (urea).

The auxiliary main valve 42 may be installed on the main exhaust 51 flow path before passing through the selective catalytic reduction reactor 30 and encountering the second bypass flow path 62.

The auxiliary main valve 42 operates in conjunction with the main valve 41. That is, when the main valve 41 is closed, the auxiliary main valve 42 also closes. The auxiliary main valve 42 prevents a relatively low temperature exhaust gas flowing through the supercharger 20 that has passed through the second bypass flow passage 62 and flows back into the selective catalytic reduction reactor 30.

However, in the first embodiment of the present invention, the auxiliary main valve 42 may be omitted in some cases.

The third bypass flow path 63 bypasses the auxiliary main valve 42 so that both ends thereof are connected to the main exhaust flow path 51, respectively. Even if the main valve 41 is closed, the exhaust gas is continuously introduced into the selective catalytic reduction reactor 30 through the first bypass flow passage 61. However, since the auxiliary main valve 42 is also closed together with the main valve 41, the internal pressure of the selective catalytic reduction reactor 30 may be continuously increased by the exhaust gas introduced through the first bypass flow path 61. have. In this case, the third bypass passage 63 discharges some or all of the exhaust gas introduced through the first bypass passage 61 to adjust the internal pressure of the selective catalytic reduction reactor 30.

The pressure regulating valve 48 is provided on the third bypass flow path 63. The pressure regulating valve 48 allows the exhaust gas to pass less than or equal to the amount of exhaust gas flowing into the selective catalytic reduction reactor 30 through the first bypass passage 61 when the auxiliary main valve 42 is closed. To open.

In addition, the pressure regulating valve 48 may include a second pressure regulating valve provided at a rear end of the first pressure regulating valve 481 and the third bypass channel 63 provided at the front end of the third bypass channel 63. 482).

Meanwhile, when the auxiliary main valve 42 is omitted, the third bypass flow path 63 and the pressure regulating valve 48 may also be omitted.

The power unit 101 including the selective catalytic reduction system according to the first embodiment of the present invention having such a configuration is selectively operated in one of the normal mode and the regeneration mode as needed.

In the normal mode, the main valve 41 is opened, and the bypass valve 43 is in the closed state. In the regeneration mode, the main valve 41 is closed, and the bypass valve 43 is opened.

Hereinafter, a detailed operation process of the normal mode of the power unit 101 including the selective catalytic reduction system according to the first embodiment of the present invention will be described with reference to FIG. 1.

In the normal mode, the main valve 41 is opened and the bypass valve 43 is closed, so that the exhaust gas having a relatively low temperature, that is, a temperature of 150 degrees Celsius or more and less than 250 degrees Celsius, passing through the supercharger 20 is selectively catalytically reduced. It is introduced into the reactor (30). In addition, a relatively small amount of exhaust gas is also introduced into the selective catalytic reduction reactor 30 through the first bypass passage 61, and the exhaust gas introduced through the first bypass passage 61 is 250 degrees Celsius to Celsius. It has a temperature in the range of 450 degrees.

The relatively high temperature exhaust gas introduced into the selective catalytic reduction reactor 30 through the first bypass flow passage 61 raises the average temperature of the entire exhaust gas introduced into the selective catalytic reduction reactor 30, thereby causing selective catalytic reduction reactor. The internal temperature of 30 can be closer to the operating temperature of the catalyst 35. Thus, the utilization efficiency of the catalyst 35 can be improved.

The flow rate of the exhaust gas flowing into the selective catalytic reduction reactor 30 through the first bypass flow passage 61 is in the range of 0.1% to 20% of the total exhaust gas generated in the engine 10. When the ratio of the exhaust gas flowing into the selective catalytic reduction reactor 30 through the first bypass passage 61 is less than 0.1%, the effect of raising the internal temperature of the selective catalytic reduction reactor 30 is insignificant, and more than 20%. Exhaust gas supplied to the rear supercharger 20 is relatively reduced, thereby reducing the supercharge efficiency of the supercharger 20. This causes a decrease in the performance of the engine 10.

The exhaust gas is mixed with the reducing agent injected by the reducing agent supply unit 37 and then introduced into the selective catalytic reduction reactor 30. The nitrogen oxide contained in the exhaust gas is reacted with a reducing agent with the help of the catalyst 35 in the selective catalytic reduction reactor 30 and is reduced with nitrogen and water vapor. That is, the exhaust gas that has passed through the selective catalytic reduction reactor 30 is purified to reduce the nitrogen oxides contained in the exhaust gas.

The exhaust gas purified through the selective catalytic reduction reactor 30 is again discharged through the main exhaust flow path 51.

On the other hand, the catalyst 35 disposed inside the selective catalytic reduction reactor 30 in order to promote the reduction reaction as the operation time passes in the normal mode is poisoned by the sulfur component contained in the fuel of the engine 10, the activity is continued Degrades.

Hereinafter, a detailed operation process of the regeneration mode of the power unit 101 including the selective catalytic reduction system according to the second embodiment of the present invention will be described with reference to FIG. 2.

In the regeneration mode, the main valve 41 is closed and the bypass valve 43 is opened, so that the exhaust gas having a relatively low temperature, that is, a temperature of 150 degrees Celsius or more and less than 250 degrees Celsius passing through the supercharger 20 is selectively catalytically reduced. It blocks the inflow into the reactor 30. In addition, a relatively high temperature exhaust gas discharged from the engine 10 directly flows into the selective catalytic reduction reactor 30 through the first bypass flow passage 61, and the exhaust flows through the first bypass flow passage 61. The gas has a temperature in the range of 250 degrees Celsius to 450 degrees Celsius. This hot exhaust gas can regenerate the poisoned catalyst in the selective catalytic reduction reactor 30. The poisoned catalyst and solids are regenerated and removed when heated to high temperatures.

The relatively low temperature exhaust gas passing through the supercharger 20 is discharged by bypassing the selective catalytic reduction reactor 30 through the second bypass flow path 62.

When the ship power unit 101 including the selective catalytic reduction system according to the first embodiment of the present invention is operated in a regeneration mode, the poisoned catalyst is regenerated. Thus, when the selective catalytic reduction reactor 30 operates within the normal range, the operation can be switched back to the normal mode to purify the exhaust gas of the engine 10. At this time, the catalyst 35 of the selective catalytic reduction reactor 30 may purify the exhaust gas with high efficiency.

As described above, the marine power unit 101 including the selective catalytic reduction system according to the first embodiment of the present invention selects and applies one of the normal mode and the regeneration mode according to the degree of poisoning of the catalyst 35. ), And the overall purification efficiency of the selective catalytic reduction reactor 30 can be improved.

By such a configuration, the ship power unit 101 including the selective catalytic reduction system according to the first embodiment of the present invention can effectively regenerate the poisoned catalyst 35 to improve the overall purification efficiency of the exhaust gas.

Specifically, the ship power unit 101 including the selective catalytic reduction system according to the first embodiment of the present invention to switch to one of the normal mode and the regeneration mode as needed to regenerate the poisoned catalyst 35 from time to time Thereby improving the purification efficiency and extending the life of the catalyst 35.

3 and 4, a ship power unit 102 including a selective catalytic reduction (SCR) system according to a second embodiment of the present invention will be described.

3 and 4, the ship power unit 102 including the selective catalytic reduction system according to the second embodiment of the present invention is an auxiliary bypass valve 45 installed in the first bypass flow path (61) It further includes. The auxiliary bypass valve 45 opens and closes with the bypass valve 43.

By such a configuration, in the normal mode, as shown in FIG. 3, the auxiliary bypass valve 45 is a catalytic reduction reactor in which exhaust gas without passing through the supercharger 20 through the first bypass flow path 61 is selected. Block 30 flows in.

Therefore, in the normal mode according to the second embodiment of the present invention, the exhaust gas directed to the turbocharger 20 is relatively increased, thereby maximizing the charging efficiency of the turbocharger 230. Therefore, it is possible to further improve the performance of the engine 10 in the normal mode.

On the other hand, in the regeneration mode, as shown in FIG. 4, relatively hot exhaust gas is directly introduced into the selective catalytic reduction reactor 30 through the first bypass flow path 61 as in the first embodiment. Therefore, the poisoned catalyst in the selective catalytic reduction reactor 30 can be regenerated by the hot exhaust gas.

By such a configuration, the marine power unit 102 including the selective catalytic reduction system according to the second embodiment of the present invention can not only effectively regenerate the poisoned catalyst 35 in the regeneration mode, but also the engine in the normal mode ( 10) can further improve the performance.

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 20: supercharger
30: Selective Catalytic Reduction Reactor 35: Catalyst
37: reducing agent supply portion 41: main valve
42: auxiliary main valve 43: bypass valve
45: auxiliary bypass valve 48: pressure regulating valve
51: main flow path 59: intake flow path
61: first bypass flow path 62: second bypass flow path
63: third bypass flow path
101, 102: Ship's power plant with selective catalytic reduction system

Claims (10)

engine;
A main exhaust passage for discharging the exhaust gas of the engine;
A selective catalytic reduction (SCR) reactor installed on the main exhaust flow path and including a catalyst;
A turbo charger installed on the main exhaust flow path between the engine and the selective catalytic reduction reactor;
A main valve installed in the main exhaust passage between the supercharger and the selective catalytic reduction reactor;
A first bypass flow passage bypassing the supercharger and supplying the exhaust gas before passing through the supercharger to the selective catalytic reduction reactor;
A second bypass flow passage bypassing the selective catalytic reduction reactor and connecting the main exhaust flow passage between the main valve and the supercharger and the main exhaust flow passage through the selective catalytic reduction reactor; And
Bypass valve installed on the second bypass flow path
Ship power device including a selective catalytic reduction system comprising a. In claim 1,
And a selective catalytic reduction system in which the main valve is open and the bypass valve is closed in normal mode and the main valve is closed and the bypass valve is selectively operated as needed in one of the open regeneration modes. 3. The method of claim 2,
In the regeneration mode, the exhaust gas, which has been relatively cooled while passing through the supercharger, is blocked from entering the selective catalytic reduction reactor,
And a selective catalytic reduction system for regenerating the catalyst by directly introducing the relatively hot exhaust gas generated in the engine into the selective catalytic reduction reactor through the first bypass flow path. 4. The method of claim 3,
And a flow rate of the exhaust gas flowing into the selective catalytic reduction reactor through the first bypass passage is in the range of 0.1% to 20% of the total exhaust gas generated in the engine. 3. The method of claim 2,
Further comprising an auxiliary bypass valve installed on the first bypass flow path,
The auxiliary bypass valve includes a selective catalytic reduction system that opens and closes with the bypass valve. In claim 1,
And a reductant supply unit which is installed in the main exhaust passage and injects a reductant into the exhaust gas before entering the selective catalytic reduction reactor. 7. The method according to any one of claims 1 to 6,
And an auxiliary main valve installed on said main exhaust flow path past said selective catalytic reduction reactor and prior to encountering said second bypass flow path. In claim 7,
And a selective catalytic reduction system bypassing the auxiliary main valve and further comprising a third bypass flow path connected at both ends to the main exhaust flow path. 9. The method of claim 8,
And a selective catalytic reduction system further comprising a pressure regulating valve disposed on the third bypass flow path. The method of claim 9,
When the auxiliary main valve is closed, the pressure regulating valve is opened to pass the exhaust gas in an amount less than or equal to the amount of the exhaust gas flowing into the selective catalytic reduction reactor through the first bypass flow path. Marine power plant including reduction system.

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