KR101902345B1 - Selective catalytic reduction system and power plant with the same - Google Patents

Abstract

A selective catalytic reduction system according to an embodiment of the present invention includes a reactor installed on a main exhaust flow path behind a supercharger installed on a main exhaust flow path, A decomposition chamber disposed on the exhaust flow path and configured to inject a reducing agent to the exhaust gas flowing into the reactor, a decomposition chamber for generating a reducing agent to be supplied to the reducing agent spraying unit by decomposing and supplying the reducing agent precursor, A branch flow path branching from a supercharger bypass flow path connected to the main exhaust flow path and connected to the decomposition chamber; an outside air supply flow path for supplying outside air to the decomposition chamber; A heating device for heating the outside air, And a flow path and flow rate control valve for controlling the flow rate of the exhaust gas to move the branch channel.

Description

TECHNICAL FIELD [0001] The present invention relates to a selective catalytic reduction system and a power unit including the selective catalytic reduction system.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a selective catalytic reduction system for reducing nitrogen oxides contained in an exhaust gas using a selective catalytic reduction reaction, and a power unit including the selective catalytic reduction system.

Generally, the power unit used in ships and the like is composed of a diesel engine for generating power, a turbocharger for supplying air to the diesel engine, and a selective catalytic reduction for reducing the nitrogen oxide contained in the exhaust gas from the diesel engine selective catalytic reduction (SCR) systems, and the like.

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 urea or ammonia (NH ₃ ) as a reducing agent to reduce nitrogen oxides.

However, when urea is directly injected into an exhaust gas having a temperature of less than 250 degrees Celsius, such as urea, biuret, cyanuric acid, melamine, and ammeline, There is a problem that the by-product obstructs the nozzle or interrupts the flow of the exhaust gas.

In order to improve the hydrolysis efficiency of the urea, a fluid heated through a separate electric heater or a burner is supplied to the decomposition chamber to raise the internal temperature of the decomposition chamber to the hydrolysis reaction temperature, and the urea is decomposed stably (NH ₃ ) and isocyanic acid (HNCO) are fed to the reactor.

However, in order to decompose urea, the internal temperature of the decomposition chamber must be raised to the hydrolysis reaction temperature. To achieve this, a separate heating device such as a burner for supplying heat energy is required. Fuel and air are consumed to start the burner.

Thus, the heat energy consumed for hydrolysis is small, and the fuel and air consumed by the burner take up a considerable proportion of the total fuel and air consumed in the selective catalytic reduction system, thereby deteriorating the overall energy utilization efficiency have.

The embodiment of the present invention provides a selective catalytic reduction system that maximizes the utilization efficiency of the total energy consumed to generate a reducing agent and reduce nitrogen oxides contained in the exhaust gas, and a power unit including the selective catalytic reduction system.

According to the embodiment of the present invention, the selective catalytic reduction system for reducing the nitrogen oxide (NOx) contained in the exhaust gas discharged through the main exhaust passage is provided on the main exhaust passage behind the supercharger installed on the main exhaust passage A decomposition chamber for generating a reducing agent to be supplied to the reducing agent spraying unit by decomposing the reducing agent precursor and supplying the reducing agent precursor to the reducing agent spraying unit, the reducing agent spraying unit being disposed on the main exhausting flow path and injecting a reducing agent into the exhaust gas, A branch flow path branching from a supercharger bypass flow path connected to the main exhaust flow path behind the supercharger and connected to the decomposition chamber; an outside air supply flow path for supplying outside air to the decomposition chamber; A heating device for heating the outside air supplied by the outside air supply passage, An air supply bypass flow path, and a flow control valve for controlling the flow rate of the exhaust gas moving through the branch flow path. Wherein the flow control valve includes a first flow control valve provided between a branch point of the supercharger bypass flow path and the branch flow path and a merging point of the supercharger bypass flow path and the main exhaust flow path, . The selective catalytic reduction system may further include a supercharger bypass valve installed on the supercharger bypass flow path and a supercharger bypass valve located in front of a branch point of the branch flow path.

The supercharger bypass passage may be connected to the main exhaust passage between the supercharger and the reactor.

The selective catalytic reduction system may further include a check valve installed on the outside air supply passage to prevent the exhaust gas flowing into the decomposition chamber through the branching passage from flowing back to the outside air supply passage.

The selective catalytic reduction system may further include a blower installed on the outside air supply flow path and sucking outside air.

And the flow control valve may be a three-way flow control valve provided at a branch point between the supercharger bypass flow path and the branch flow path.

According to another embodiment of the present invention, there is provided a selective catalytic reduction system for reducing nitrogen oxides (NOx) contained in exhaust gas discharged through a main exhaust passage, comprising a main catalytic converter disposed downstream of the turbocharger installed on the main exhaust passage, A reducing agent spraying part provided on the flow path and spraying a reducing agent onto the exhaust gas flowing on the main exhaust flow path to the reactor; A branch flow path branching from a supercharger bypass flow path connected to the main exhaust flow path between the supercharger and the reactor and connected to the decomposition chamber, an outside air supply flow path for supplying outside air to the decomposition chamber, And heats the outside air supplied by the outside air supply passage A first temperature sensor and a first flowmeter provided on the branch flow path respectively, and a second flow sensor connected to the first flow sensor and the second flow sensor, wherein the flow rate control valve controls the flow rate of the exhaust gas flowing through the supercharger bypass flow path and the branch flow path, And a second temperature sensor installed to measure the temperature of the outside air passing through the heating device.

The selective catalytic reduction system may further include a blower installed on the outside air supply flow path and sucking outside air.

The selective catalytic reduction system may further include a control unit for receiving information from the first temperature sensor, the first flow meter, and the second temperature sensor and controlling the opening and closing of the flow control valve and the operation of the blower and the heating device .

Wherein the controller calculates a quantity of heat supplied to the decomposition chamber from the information obtained from the first temperature sensor and the first flow meter through the branch passage and calculates a quantity of heat required to generate the reducing agent in the decomposition chamber The opening rate of the flow control valve can be adjusted so as to follow the flow rate control valve.

The control unit calculates the amount of heat supplied to the decomposition chamber from the information obtained from the first temperature sensor and the first flow meter through the branch passage, and when the calculated amount of heat exceeds the amount of heat required to generate the reducing agent, The control valve can be controlled to reduce the flow rate of the exhaust gas flowing into the branch passage.

The selective catalytic reduction system may include a second flow meter installed on the outside air supply flow path and measuring a flow rate of the outside air sucked by the blower, The controller may further include a controller for controlling the opening and closing of the flow rate control valve and the operation of the blower and the heating device by receiving information from the second flow meter.

According to another aspect of the present invention, there is provided a selective catalytic reduction system for reducing nitrogen oxides (NOx) contained in exhaust gas discharged through a main exhaust passage, comprising: A reducing agent spraying part provided on the exhaust flow path and spraying a reducing agent to the exhaust gas which is provided on the main exhaust flow path and which moves to the reactor; and a reducing agent supplying part for decomposing the reducing agent precursor to supply the reducing agent to the reducing agent spraying part A branch flow path branching from a supercharger bypass flow path connected to the main exhaust flow path between the supercharger and the reactor and connected to the decomposition chamber, an outside air supply flow path for supplying outside air to the decomposition chamber, And is provided on the flow path to heat the outside air supplied by the outside air supply path A first temperature sensor and a first flow meter provided on the branch passage, and a second temperature sensor provided on the branch passage, Wherein the control unit calculates the amount of heat to be supplied to the decomposition chamber from the information obtained from the first flow meter through the branch passage, and when the calculated heat amount is lower than the heat amount required to generate the reducing agent in the decomposition chamber, And a control unit for additionally supplying heat to the decomposition chamber through the supply passage.

And a blower installed on the outside air supply flow path and sucking outside air.

The selective catalytic reduction system includes a second flow meter installed on the outside air supply flow path and measuring a flow rate of the outside air sucked by the blower, and a second flow meter installed on the outside air supply flow path to measure the temperature of the outside air passing through the heating device And may further include a second temperature sensor. The control unit calculates the amount of heat supplied to the decomposition chamber through the outside air supply passage from the information obtained from the second temperature sensor and the second flow meter, and the control unit calculates the amount of heat supplied through the branch passage, The degree of operation of the blower and the heating device can be controlled so that the sum of the heat amount supplied through the flow path follows the amount of heat required to generate the reducing agent in the decomposition chamber.

According to another embodiment of the present invention, the power unit further includes an engine for exhausting exhaust gas containing nitrogen oxides (NOx), a main exhaust passage through which the exhaust gas discharged from the engine moves, A supercharger bypass passage connected to the main exhaust passage between the supercharger and the reactor, and the selective catalytic reduction system described above.

According to the embodiment of the present invention, the selective catalytic reduction system and the power unit including the selective catalytic reduction system can maximize the utilization efficiency of the total energy consumed to generate the reducing agent and reduce the nitrogen oxide contained in the exhaust gas.

1 is a configuration diagram of a power unit including a selective catalytic reduction system according to an embodiment of the present invention.
FIGS. 2 and 3 are block diagrams showing an operation state of the power unit including the selective catalytic reduction system of FIG.
4 is a configuration diagram of a power unit including a selective catalytic reduction system according to a modification of the 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 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 to 3, a selective catalytic reduction (SCR) system 201 according to an embodiment of the present invention and a power unit 101 including the selective catalytic reduction system 201 will be described. The selective catalytic reduction system 201 according to an embodiment of the present invention may be manufactured and assembled together with the engine 100 as a component of the power unit 101. In some cases, (NOx) contained in the exhaust gas discharged from the exhaust gas recirculation line 100. In detail, the selective catalytic reduction system 201 according to an embodiment of the present invention, in order to improve the environmentally-friendly performance of the engine 100 installed in the course of repairing and repairing a vehicle or a vehicle or a land or a marine plant, Can be installed.

1 to 3, a power unit 101 including a selective catalytic reduction (SCR) system 201 according to an embodiment of the present invention includes an engine 100, a main exhaust passage The supercharger bypass passage 620, the reducing agent injection portion 570, the decomposition chamber 500, the branch passage 630, the outside air supply passage 640, the blower 410 ), And a heating device 420.

The power unit 101 including the selective catalytic reduction system 201 according to an embodiment of the present invention includes an exhaust receiver 180, a supercharger bypass valve 720, a check valve 770, a flow control valve The first temperature sensor 811, the first flow meter 812, the second flow meter 822, the second temperature sensor 821, and the control unit 700. The first temperature sensor 811,

The engine 100 is a main power source for generating power in ships and automobiles. In one embodiment of the present invention, various engines that exhaust exhaust gas containing nitrogen oxides (NOx) may be used as the engine 100.

The supercharger 150 is installed on a main exhaust flow path to be described later. The turbocharger 150 boosts the efficiency of the engine 100 by compressing and supplying new external air to the engine 100 by turning the turbine with the pressure of the exhaust gas of the engine 100.

The exhaust receiver 180 has an unbalanced pressure in the cylinder reciprocating motion of the engine 100 to uniformly alleviate the exhaust gas of the exhausted engine 100.

In an embodiment of the present invention, the exhaust gas discharged by the engine 100 has a temperature within a range of 250 degrees Celsius to 500 degrees Celsius, and the temperature of the exhaust gas can be lowered through the supercharger 150. For example, the exhaust gas passing through the turbocharger 150 may be lowered to a temperature of not less than 150 degrees Celsius and less than 250 degrees Celsius.

The main exhaust passage 610 is connected to the exhaust port of the engine 100 to exhaust the exhaust gas of the engine 100. That is, the exhaust gas of the engine 100 moves along the main exhaust flow path 610.

The main exhaust passage 610 sequentially connects the engine 100 with the turbocharger 150 and the reactor 300 to be described later. Thus, the main exhaust gas passage 610 supplies the exhaust gas of the engine 100 through the turbocharger 150 to the reactor 300.

The reactor 300 is installed on the main exhaust passage 610. The reactor 300 includes a catalyst for reducing nitrogen oxides (NOx) contained in the exhaust gas discharged from the engine 100. The catalyst promotes the reaction of the reducing agent with the nitrogen oxides (NOx) contained in the exhaust gas and reduces the nitrogen oxides (NOx) to nitrogen and water vapor. At this time, ammonia (NH ₃ ) may be used as a final reducing agent to react with and reduce nitrogen oxides (NO x).

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

Specifically, the poisoning substance that poisons the catalyst may include at least one of ammonium sulfate (NH ₄ ) ₂ SO ₄ and ammonium hydrogen sulfite (NH ₄ HSO ₄ ). Such a catalyst poisoning material is adsorbed on the catalyst to lower the activity of the catalyst. Since the catalyst poisonous substance decomposes at a relatively high temperature, the poisoned catalyst can be regenerated by raising the temperature of the catalyst.

Also, the housing of the reactor 300 can be made of, for example, stainless steel.

The decomposition chamber 500 generates ammonia (NH ₃ ) which is used as a reducing agent to reduce nitrogen oxide (NOx) by decomposing the urea (CO (NH ₂ ) ₂ ) as a reducing agent precursor.

If specifically, the temperature in the decomposition chamber 500 is maintained within Celsius 300 degrees to degrees Celsius to 500 degrees, urea (urea, CO (NH _{2) 2)} is as easily hydrolyzed ammonia (NH ₃₎ and isocyanate ( Isocyanic acid, HNCO). And isocyanate (HNCO) is decomposed again into ammonia (NH ₃ ) and carbon dioxide (CO ₂ ). That is, when urea is decomposed, ammonia may finally be generated.

The reducing agent spraying unit 570 injects ammonia (NH ₃ ) generated in the decomposition chamber 500 into the exhaust gas to be introduced into the reactor 300. The injected ammonia is mixed with the exhaust gas to reduce the nitrogen oxide contained in the exhaust gas through the catalyst of the reactor 300.

Specifically, the reducing agent spraying unit 570 can spray ammonia (NH ₃ ) toward the exhaust gas flowing along the main exhaust flow path 610 in front of the reactor 300.

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

The urea supply unit 550 supplies urea, which is a reducing agent precursor, to the decomposition chamber 500. The urea supply unit 550 supplies an appropriate amount of urea to the decomposition chamber 500 in consideration of the amount of the reducing agent that varies depending on the load of the engine 100. That is, the urea supply unit 550 can be supplied in accordance with the amount of reducing agent required under the control of the control unit 700, which will be described later.

The supercharger bypass flow passage 620 branches off from the main exhaust flow passage 610, bypasses the turbocharger 150, and joins the main exhaust flow passage 610 again. That is, the exhaust gas traveling through the turbocharger bypass passage 620 does not pass through the turbocharger 150, and thus has a relatively high temperature as compared with the exhaust gas passing through the turbocharger 150. The supercharger bypass passage 620 may be connected to the exhaust receiver 180 as shown in FIG.

The supercharger bypass valve 720 is installed on the supercharger bypass flow passage 620.

Specifically, the supercharger bypass valve 720 is installed on the supercharger bypass flow passage 620 in front of the branch point of the supercharger bypass flow passage 620 and a branch flow passage 630 to be described later.

The supercharger bypass valve 720 can be used to regulate the combustion pressure and the heat load in the combustion chamber of the engine 100.

The supercharger bypass valve 720 can also be used for supplying the exhaust gas to the decomposition chamber 500 through the branch passage 630, which will be described later.

When the combustion pressure in the combustion chamber and the heat load of the engine 100 increase beyond the allowable value, the turbocharger bypass valve 720 is opened to allow a part of the exhaust gas to flow to the turbocharger bypass passage 620 to be supplied to the turbocharger 150 Thereby reducing the flow rate of the exhaust gas. Accordingly, the pressure of the compressed air supplied to the engine 100 by the turbocharger 150 is reduced, and the combustion pressure in the combustion chamber of the engine 100 can be controlled.

As described above, the supercharger bypass valve 720 can be independently operated independently of the flow control valve 710 to be described later.

The branch flow path 630 branches from the supercharger bypass flow path 620 and is connected to the decomposition chamber 500.

That is, the branch flow channel 630 transfers the exhaust gas having a relatively high temperature moving in the supercharger bypass flow channel 620 to the decomposition chamber 500 to hydrolyze the urea in the decomposition chamber 500 to generate ammonia Provide necessary thermal energy.

The flow control valve 710 controls the flow rate of the exhaust gas flowing through the supercharger bypass flow path 620 and the branch flow path 630. For example, the flow control valve 710 may be a three-way flow control valve installed at a branch point between the supercharger bypass flow path 620 and the branch flow path 630.

The first temperature sensor 811 and the first flow meter 812 are installed on the branch flow path 630.

In an embodiment of the present invention, the amount of heat supplied to the decomposition chamber 500 through the branch channel 630 with the temperature information and the flow rate information measured by the first temperature sensor 811 and the first flow meter 812, Can be calculated. The rate of opening of the flow control valve 710 can be adjusted so that the calculated calorie amount will follow the amount of heat required to hydrolyze the reducing agent precursor urea in the decomposition chamber 500 to produce ammonia as a reducing agent.

In this way, the flow control valve 710 controls the amount of heat required to generate the reducing agent in the decomposition chamber 500 to be supplied to the decomposition chamber 500 through the branch flow channel 630, The flow rate of the exhaust gas that is diverted to the branch flow path 630 can be adjusted.

The amount of heat supplied to the decomposition chamber 500 through the branch flow path 630 is calculated from the information obtained from the first temperature sensor 811 and the first flow meter 812. The calculated amount of heat is decomposed If the amount of heat required in the chamber 500 is exceeded, the flow control valve 630 may be adjusted to reduce the flow rate of the exhaust gas flowing to the branch flow path 630.

That is, when the exhaust gas moving along the supercharger bypass flow path 620 supplies and supplies the required amount of heat to the decomposition chamber 500 through the branch flow path 630, the remaining exhaust gas corresponding to the remaining heat amount flows through the branch flow path 630 and moves along the bypass bypass passage 620 as it is, and joins the main exhaust passage 610 again.

The exhaust gas combined with the main exhaust passage 610 via the supercharger bypass flow path 620 is combined with the exhaust gas whose temperature has been lowered through the turbocharger 150 so that the temperature of the exhaust gas flowing into the reactor 300 The temperature can be raised.

As described above, the temperature of the exhaust gas passing through the turbocharger 150 can be lowered to more than 150 degrees Celsius and less than 250 degrees Celsius. When the cigarette having such a relatively low temperature flows into the reactor 300, Or the catalyst may be poisoned.

That is, the exhaust gas combined with the main exhaust flow path 610 through the supercharger bypass flow path 620 can raise the temperature of the exhaust gas flowing into the reactor 300, thereby maintaining the activity of the catalyst and suppressing poisoning of the catalyst.

The outside air supply passage 640 supplies outside air to the decomposition chamber 500. That is, the outside air supply passage 640 branches off from the supercharger bypass passage 620 and supplies air other than the exhaust gas supplied through the branch passage 630 to the decomposition chamber 500.

The blower 410 and the heating device 420 are installed on the outside air supply passage 640. The blower 410 sucks the outside air through the outside air supply passage 640. The heating device 420 heats the outside air sucked by the blower 410. For example, the heating device 420 may be one of an oil burner, a plasma burner, or an electric heater

The backflow prevention valve 770 is provided on the outside air supply passage 640 to prevent the exhaust gas flowing into the decomposition chamber 500 through the branch passage 630 from flowing backward to the outside air supply passage 640.

The amount of heat supplied to the decomposition chamber 500 through the branch flow path 630 is calculated from the information obtained from the first temperature sensor 811 and the first flow meter 812, If the amount of heat required to generate the reducing agent in the decomposition chamber 500 is lower than the amount of heat required to generate the reducing agent in the decomposition chamber 500, the blower 410 and the heating device 420 may be operated to additionally supply heat to the decomposition chamber 500 through the outside air supply passage 640 have.

In addition, in an embodiment of the present invention, since the heating device 420 for additionally supplying heat energy is provided in the outside air supply line 640, when the burner requiring combustion air is used as the heating device 420, It is easy and effective to supply oxygen.

On the other hand, unlike the embodiment of the present invention, if the heating device 420 is installed in the branch passage 630, the oxygen concentration of the exhaust gas moving along the branch passage 630 is low, ). ≪ / RTI >

The second flow meter 822 is installed on the outside air supply passage 640. The second flow meter 822 measures the flow rate of the outside air sucked by the blower 410.

The second temperature sensor 821 is installed on the outside air supply passage 640. Specifically, the second temperature sensor 821 can be installed on the outside air supply passage 640 behind the heating device 420. The second temperature sensor 821 measures the temperature of the outside air through the heating device 420.

In an embodiment of the present invention, the second temperature sensor 821 and the second flow meter 822 supply temperature information and flow rate information to the decomposition chamber 500 through the outside air supply passage 640 Calories can be calculated.

In an embodiment of the present invention, the sum of the amount of heat supplied through the branch passage 630 and the amount of heat supplied through the outside air supply passage 640 follows the amount of heat required to generate the reducing agent in the decomposition chamber 500 The operation of the blower 410 and the heating device 420 can be adjusted.

The control unit 700 receives information from the first temperature sensor 811, the first flow meter 812, the second temperature sensor 821 and the second flow meter 822 to open and close the flow control valve 710, 410 and the heating device 420 can be controlled.

That is, the control unit 700 calculates the amount of heat supplied to the decomposition chamber 500 through the branch channel 630 and the amount of heat supplied to the decomposition chamber 500 through the outside air supply channel 640, The flow control valve 710 and the blower 410 and the heating device 420 can be controlled so as to follow the amount of heat required to hydrolyze the reducing agent precursor urea in the decomposition chamber 500 to generate ammonia as the reducing agent have.

The control unit 700 may control the urea supply unit 550 that supplies the urea to the decomposition chamber 500 according to the amount of the reducing agent required in view of the load variation of the engine 100. [

With this configuration, the power plant 101 including the selective catalytic reduction system 201 according to the embodiment of the present invention can reduce the total amount of energy consumed to generate the reducing agent and reduce the nitrogen oxide contained in the exhaust gas. Thereby maximizing the efficiency.

Specifically, according to an embodiment of the present invention, the thermal energy of the exhaust gas before being exhausted from the engine 100 through the supercharger bypass passage 620 and the branch passage 630 and before passing through the turbocharger 150, Can be utilized to generate a reducing agent in the reactor 500.

In addition, since the ship is used in various climatic zones, the amount of reducing agent required varies depending on the load variation of the engine 100 and the environmental change, and the amount of the reducing agent is reduced through the supercharger bypass passage 620 and the branch passage 630 500 is also different.

However, according to an embodiment of the present invention, the amount of heat supplied to the decomposition chamber 500 through the turbocharger bypass passage 620 and the branch passage 630 and the amount of heat supplied to the decomposition chamber 500 through the outside air supply passage 640 The flow rate control valve 710 and the blower 410 are controlled so as to follow the amount of heat required to generate the ammonia as the reducing agent by hydrolyzing the urea as the reducing agent precursor in the decomposition chamber 500 And the heating device 420 can be adjusted. That is, even in the case of load fluctuation and environmental change of the engine 100, it is possible to maximize the utilization efficiency of the total energy consumed to generate the reducing agent and reduce the nitrogen oxide contained in the exhaust gas.

4, the power unit 102 including the selective catalytic reduction system 202 is provided with a first flow control valve 711 and a second flow control valve (712). ≪ / RTI >

The first flow control valve 711 is installed between the branch point of the supercharger bypass flow passage 620 and the branch flow passage 630 and the confluence point of the supercharger bypass flow passage 620 and the main exhaust flow passage 610.

The second flow control valve 712 is installed on the branched oil 630.

That is, in this modification, two flow control valves 711 and 712 are used instead of one three-way flow control valve, and the configuration and operation principle are the same as those of the embodiment of the present invention.

Hereinafter, the operation principle of the power unit 101 including the selective catalytic reduction system 201 according to an embodiment of the present invention will be described with reference to FIG. 1 to FIG.

1, the control unit 700 receives the temperature information and the flow rate information measured by the first temperature sensor 811 and the first flow meter 812 through the branch channel 630 to the decomposition chamber 500 And calculates the supplied heat quantity.

The control unit 700 does not operate the blower 410 and the heating unit 420 when the calculated heat amount satisfies the amount of heat required for generating the reducing agent in the decomposition chamber 500. That is, according to the embodiment of the present invention, unnecessary energy can be prevented from being wasted.

2, the control unit 700 receives the temperature information and flow rate information measured by the first temperature sensor 811 and the first flow meter 812 through the branch channel 630, And adjusts the opening rate of the flow control valve 710 so that the calculated heat amount follows the amount of heat required to generate the reducing agent in the decomposition chamber 500. [

That is, when the calculated amount of heat exceeds the amount of heat required to generate the reducing agent, the control unit 700 controls the flow control valve 710 to reduce the flow rate of the exhaust gas moving to the branch flow channel 630.

The remaining exhaust gas corresponding to the amount of heat remaining after supplying the required amount of heat to the decomposition chamber 500 is moved along the bypass bypass passage 620 as it is without being directed toward the branch passage 630 and is supplied to the main exhaust passage 610 Join.

The exhaust gas combined with the main exhaust passage 610 via the supercharger bypass flow path 620 is combined with the exhaust gas whose temperature has been lowered through the turbocharger 150 so that the temperature of the exhaust gas flowing into the reactor 300 The temperature can be raised.

3, the control unit 700 receives the temperature information and the flow rate information measured by the first temperature sensor 811 and the first flow meter 812 through the branch channel 630, If the calculated heat amount is lower than the heat amount required to generate the reducing agent in the decomposition chamber 500, the blower 410 and the heating device 420 are operated to supply the outside air supply flow path 640 And further supplies heat to the decomposition chamber 500 through the heat exchanger.

The control unit 700 calculates the amount of heat supplied to the decomposition chamber 500 through the outside air supply flow path 640 from the information obtained from the second temperature sensor 821 and the second flow meter 822, And the amount of heat supplied through the outside air supply passage 640 follows the operation amount of the blower 410 and the heating device 420 so as to follow the amount of heat required to generate the reducing agent in the decomposition chamber 500 Can be controlled.

By this operation, the power unit 101 including the selective catalytic reduction system 201 according to the embodiment of the present invention can utilize the total energy consumed to generate the reducing agent and reduce the nitrogen oxide contained in the exhaust gas. Thereby maximizing the efficiency.

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.

100: engine
101, 102: Power unit
150: supercharger
201, 202: Selective Catalytic Reduction System
300: reactor
410: Blower
420: Heating device
500: decomposition chamber
550: urea supply part
570: Reducing agent dispensing part
610: Main exhaust channel
620: Supercharger bypass flow
630:
640: Air supply channel
700:
710: Flow control valve
720: Supercharger bypass valve
770: Anti-backflow valve
811: first temperature sensor
812: First flow meter
821: second temperature sensor
822: Second flow meter

Claims (15)

An exhaust gas purifier for an internal combustion engine, comprising: an engine; a supercharger for supplying compressed air to the engine; an exhaust receiver disposed between the engine and the turbocharger to receive exhaust gas discharged from the engine; 1. A selective catalytic reduction system for reducing nitrogen oxides (NOx) contained in an exhaust gas discharged from a marine power plant including a flow path,
A reactor disposed on the main exhaust flow path behind the supercharger installed on the main exhaust flow path;
A reducing agent spraying unit installed on the main exhaust flow path and spraying a reducing agent to the exhaust gas moving to the reactor;
A decomposition chamber for supplying a reducing agent precursor to decompose and generate a reducing agent to be supplied to the reducing agent spraying unit;
A branch flow path branched from a supercharger bypass flow path, one end of which is connected to the exhaust receiver and the other end is connected to the main exhaust flow path behind the supercharger and bypasses the supercharger,
An outside air supply passage for supplying outside air to the decomposition chamber;
A burner installed on the outside air supply passage for heating outside air supplied through the outside air supply passage;
A first flow control valve provided between a branch point of the supercharger bypass flow path and the branch flow path and a merging point of the supercharger bypass flow path and the main exhaust flow path;
A second flow control valve provided on the branch flow path; And
And a supercharger bypass valve provided on the supercharger bypass flow path and at a branching point of the branch flow path on the supercharger bypass flow path. The method according to claim 1,
And the other end of the supercharger bypass passage is connected to the main exhaust passage between the supercharger and the reactor. The method according to claim 1,
Further comprising a backflow prevention valve installed on the outside air supply flow passage to prevent the exhaust gas flowing into the decomposition chamber through the branching flow passage from flowing back to the outside air supply flow passage. The method according to claim 1,
Further comprising a blower installed on the outside air supply flow passage and sucking outside air to supply combustion air to the burner. The method according to claim 1,
Wherein the flow control valve is a three-way flow rate control valve provided at a branch point between the supercharger bypass flow path and the branch flow path. An exhaust gas purifier for an internal combustion engine, comprising: an engine; a supercharger for supplying compressed air to the engine; an exhaust receiver disposed between the engine and the turbocharger to receive exhaust gas discharged from the engine; 1. A selective catalytic reduction system for reducing nitrogen oxides (NOx) contained in an exhaust gas discharged from a marine power plant including a flow path,
A reactor disposed on the main exhaust flow path behind the supercharger installed on the main exhaust flow path;
A reducing agent spraying unit installed on the main exhaust flow path and spraying a reducing agent to the exhaust gas moving to the reactor;
A decomposition chamber for supplying a reducing agent precursor to decompose and generate a reducing agent to be supplied to the reducing agent spraying unit;
A branch duct connected to the exhaust receiver at one end and connected to the decomposition chamber by branching from a supercharger bypass flow passage which is connected to the main exhaust flow passage between the supercharger and the reactor and bypasses the supercharger at the other end;
An outside air supply passage for supplying outside air to the decomposition chamber;
A burner installed on the outside air supply passage to heat the outside air supplied by the outside air supply passage;
A flow control valve for controlling the flow rate of the exhaust gas flowing through the supercharger bypass passage and the branch passage;
A first temperature sensor and a first flow meter provided on the branch passage; And
A second temperature sensor installed on the outside air supply passage and measuring the temperature of the outside air passing through the burner,
≪ / RTI > The method according to claim 6,
Further comprising a blower installed on the outside air supply flow passage and sucking outside air to supply combustion air to the burner. 8. The method of claim 7,
A second flow meter installed on the outside air supply flow path and measuring a flow rate of the outside air sucked by the blower; And
A control unit which receives information from the first temperature sensor, the first flow meter, the second temperature sensor, and the second flow meter and controls the opening and closing of the flow control valve and the operation of the blower and the burner
≪ / RTI > 8. The method of claim 7,
Further comprising a control unit for receiving information from the first temperature sensor, the first flow meter, and the second temperature sensor and controlling the opening and closing of the flow control valve and the operation of the blower and the burner. The method of claim 9,
Wherein the controller calculates a quantity of heat supplied to the decomposition chamber from the information obtained from the first temperature sensor and the first flow meter through the branch passage and calculates a quantity of heat required to generate the reducing agent in the decomposition chamber Wherein the opening ratio of the flow control valve is adjusted so as to follow the flow rate control valve. The method of claim 9,
The control unit calculates the amount of heat supplied to the decomposition chamber from the information obtained from the first temperature sensor and the first flow meter through the branch passage, and when the calculated amount of heat exceeds the amount of heat required to generate the reducing agent, And a control valve is controlled to reduce the flow rate of the exhaust gas moving to the branch passage. An exhaust gas purifier for an internal combustion engine, comprising: an engine; a supercharger for supplying compressed air to the engine; an exhaust receiver disposed between the engine and the turbocharger to receive exhaust gas discharged from the engine; 1. A selective catalytic reduction system for reducing nitrogen oxides (NOx) contained in an exhaust gas discharged from a marine power plant including a flow path,
A reactor disposed on the main exhaust flow path behind the supercharger installed on the main exhaust flow path;
A reducing agent spraying unit installed on the main exhaust flow path and spraying a reducing agent to the exhaust gas moving to the reactor;
A decomposition chamber for supplying a reducing agent precursor to decompose and generate a reducing agent to be supplied to the reducing agent spraying unit;
A branch duct connected to the exhaust receiver at one end and connected to the decomposition chamber by branching from a supercharger bypass flow passage which is connected to the main exhaust flow passage between the supercharger and the reactor and bypasses the supercharger at the other end;
An outside air supply passage for supplying outside air to the decomposition chamber;
A burner installed on the outside air supply passage to heat the outside air supplied by the outside air supply passage;
A flow control valve for controlling the flow rate of the exhaust gas flowing through the supercharger bypass passage and the branch passage;
A first temperature sensor and a first flow meter provided on the branch passage; And
Wherein the controller calculates the amount of heat supplied to the decomposition chamber through the branch passage from the information obtained from the first temperature sensor and the first flow meter and, if the calculated heat amount is lower than the heat amount required to generate the reducing agent in the decomposition chamber A control unit for operating the burner to additionally supply heat to the decomposition chamber,
≪ / RTI > 13. The method of claim 12,
Further comprising a blower installed on the outside air supply flow passage and sucking outside air to supply combustion air to the burner. 14. The method of claim 13,
A second temperature sensor installed on the outside air supply path and measuring the temperature of the outside air passing through the burner; And
A second flow meter installed on the outside air supply passage for measuring a flow rate of the outside air sucked by the blower,
Further comprising:
Wherein the controller calculates the amount of heat supplied to the decomposition chamber through the outside air supply passage from the information obtained from the second temperature sensor and the second flowmeter,
The control unit controls the degree of operation of the blower and the burner so that the sum of the amount of heat supplied through the branch passage and the amount of heat supplied through the outside air supply passage follows the amount of heat required to generate the reducing agent in the decomposition chamber Selective Catalytic Reduction System. An engine for exhausting exhaust gas containing nitrogen oxides (NOx);
A supercharger for supplying compressed air to the engine;
An exhaust receiver disposed between the engine and the turbocharger to receive exhaust gas discharged from the engine;
A main exhaust passage for exhausting the exhaust gas of the engine to the outside;
A supercharger bypass passage connected to the exhaust receiver at one end and connected to the main exhaust passage between the supercharger and the reactor by bypassing the supercharger at the other end; And
A selective catalytic reduction system according to any one of the claims 1 to 14
≪ / RTI >

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