KR102107906B1 - Selective catalytic reduction system and power plant with the same - Google Patents

Abstract

The present invention relates to a selective catalytic reduction system and a power device including the same, wherein the selective catalytic reduction system according to an embodiment of the present invention includes a reactor installed on the main exhaust passage behind the supercharger installed on the main exhaust passage, and the main A reducing agent injection unit installed on an exhaust flow path to inject a reducing agent into the exhaust gas moving to the reactor, a decomposition chamber for receiving a reducing agent precursor to decompose to generate a reducing agent to be supplied to the reducing agent injection unit, and the rear of the turbocharger A branch flow path branched from the turbocharger bypass flow path connected to the main exhaust flow path and connected to the decomposition chamber, an external air supply flow path for supplying external air to the decomposition chamber, and an external air supply flow path provided on the outdoor air flow path to supply Heating device for heating the outside air, and the supercharger bypass And a flow path and flow rate control valve for controlling the flow rate of the exhaust gas to move the branch channel.

Description

SELECTIVE CATALYTIC REDUCTION SYSTEM AND POWER PLANT WITH THE SAME

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

In general, power devices used in ships, etc. are diesel engines that generate power, turbochargers that supply scavenging air to diesel engines, and selective catalytic reduction to reduce nitrogen oxides contained in exhaust gas emitted from diesel engines. (selective catalytic reduction, SCR) system.

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

The selective catalytic reduction system uses urea or ammonia (NH ₃ ) as a reducing agent for reducing nitrogen oxides.

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

Thus, in order to improve the hydrolysis efficiency of urea, the heated fluid is supplied to the decomposition chamber through a separate electric heater or burner to increase the internal temperature of the decomposition chamber to the hydrolysis reaction temperature, and the urea is stably decomposed in the decomposition chamber. Ammonia (NH ₃ ) and isocyanic acid (HNCO) produced by the method are used.

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

As described above, the heat energy consumed for the hydrolysis is not small, and the fuel and air consumed by the burner occupy a significant proportion of the total fuel and air consumed in the selective catalytic reduction system, thereby deteriorating the overall energy utilization efficiency. have.

An embodiment of the present invention provides a selective catalytic reduction system that maximizes the efficiency of use of the overall energy consumed to generate a reducing agent and reduce nitrogen oxides contained in exhaust gas, and a power device including the same.

According to an embodiment of the present invention, a selective catalytic reduction system for reducing nitrogen oxides (NOx) contained in exhaust gas discharged through the main exhaust passage is provided on the main exhaust passage behind the supercharger installed on the main exhaust passage. An installed reactor, a reducing agent injection unit installed on the main exhaust flow path to inject a reducing agent into the exhaust gas moving to the reactor, and a decomposition chamber for receiving a reducing agent precursor to decompose to generate a reducing agent to be supplied to the reducing agent injection unit, A branch flow path branched from a supercharger bypass flow path connected to the main exhaust flow path behind the supercharger and connected to the decomposition chamber, an external air supply flow path for supplying external air to the decomposition chamber, and installed on the outdoor air supply flow path A heating device for heating the outside air supplied by the outside air supply passage, and the above It includes a flow control valve for controlling the flow rate of the exhaust gas moving through the air supply bypass flow path and the branch flow path. The flow control valve includes a first flow control valve installed between a branch point of the turbocharger bypass flow path and the branch flow path, and a confluence point of the turbocharger bypass flow path and the main exhaust flow path, and a second flow control valve installed on the branch flow path. It includes. In addition, the selective catalytic reduction system further includes a supercharger bypass valve installed on the supercharger bypass flow path and the supercharger bypass flow path in front of the branch point of the branch flow path.

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

The selective catalytic reduction system may further include a backflow prevention valve that is installed on the external air supply flow path and prevents exhaust gas flowing into the decomposition chamber through the branch flow path to flow back into the external air supply flow path.

The selective catalytic reduction system may further include a blower that is installed on the external air supply flow path and sucks in outdoor air.

The flow control valve may be a three-way flow control valve installed at a branch point of the turbocharger bypass flow path and the branch flow path.

In addition, according to another embodiment of the present invention, the selective catalytic reduction system for reducing nitrogen oxides (NOx) contained in exhaust gas discharged through the main exhaust passage is the main exhaust behind the supercharger installed on the main exhaust passage. A reactor installed on a flow path, a reductant injection portion that is installed on the main exhaust flow path to inject a reducing agent to the exhaust gas moving to the reactor, and a decomposition to receive and decompose a reducing agent precursor to generate a reducing agent to be supplied to the reducing agent injection portion A branch flow path branched from a turbocharger bypass flow path connected to the main exhaust flow path between the chamber, the supercharger and the reactor, and connected to the decomposition chamber, an external air supply flow path for supplying outdoor air to the decomposition chamber, and the outdoor air supply flow path Is installed on the heating the outside air supplied by the outside air supply passage A device, a flow rate control valve for controlling the flow rate of the exhaust gas moving through the turbocharger bypass flow path and the branch flow path, a first temperature sensor and a first flow meter respectively installed on the branch flow path, and on the external air supply flow path It is installed and includes a second temperature sensor for measuring the temperature of the outside air that has passed through the heating device.

The selective catalytic reduction system may further include a blower that is installed on the external air supply flow path and sucks in outdoor air.

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

The control unit calculates the amount of heat supplied to the decomposition chamber through the branch flow path from the information obtained from the first temperature sensor and the first flow meter, and calculates the amount of heat required to generate the reducing agent in the decomposition chamber. The opening rate of the flow control valve can be adjusted to follow.

The control unit calculates the amount of heat supplied to the decomposition chamber through the branch flow path from the information obtained from the first temperature sensor and the first flow meter, and when the calculated amount of heat exceeds the amount of heat required to generate the reducing agent, the agent 2 By controlling the flow rate control valve, the flow rate of the exhaust gas moving to the branch flow path can be reduced.

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

In addition, according to another embodiment of the present invention, a selective catalytic reduction system for reducing nitrogen oxides (NOx) contained in exhaust gas discharged through the main exhaust passage is the main of the rear of the turbocharger installed on the main exhaust passage. A reactor installed on an exhaust flow path, a reducing agent injection portion for spraying a reducing agent to the exhaust gas installed on the main exhaust flow path, and a reducing agent precursor to be decomposed to generate a reducing agent to be supplied to the reducing agent injection portion A branching channel connected to the decomposition chamber branched from a decomposition chamber, a supercharger bypass flow path connected to the main exhaust flow path between the supercharger and the reactor, and an external air supply flow path for supplying external air to the decomposition chamber, and the outdoor air supply It is installed on the flow path to heat the outside air supplied by the outside air supply flow path. A heating device, a flow rate control valve for controlling the flow rate of the exhaust gas moving through the turbocharger bypass flow path and the branch flow path, a first temperature sensor and a first flow meter installed on the branch flow path, and the first temperature sensor Calculate the amount of heat supplied to the decomposition chamber through the branch flow path from the information obtained from the first flow meter, and when the calculated amount of heat is lower than the amount of heat required to generate a reducing agent in the decomposition chamber, the heating device is operated to operate the outside air. It includes a control unit for additionally supplying the amount of heat to the decomposition chamber through the supply passage.

It may be further installed on the outside air supply flow path may further include a blower for sucking the outside air.

The selective catalytic reduction system is installed on the external air supply flow path and is installed on the external air supply flow path and a second flow meter that measures the flow rate of the outdoor air sucked by the blower and measures the temperature of the external air that has passed through the heating device. A second temperature sensor may be further included. And the control unit calculates the amount of heat supplied to the decomposition chamber through the outside air supply channel from the information obtained from the second temperature sensor and the second flow meter, and the control unit supplies the amount of heat supplied through the branch channel and the outside air The degree of operation of the blower and the heating device can be controlled such that the sum of the amount of heat supplied through the flow path follows the amount of heat required to generate the reducing agent in the decomposition chamber.

In addition, according to another embodiment of the present invention, the power unit includes an engine that discharges exhaust gas containing nitrogen oxides (NOx), a main exhaust channel through which the exhaust gas discharged by the engine moves, and the main exhaust channel A supercharger installed on the bed, a supercharger bypass flow path connected to the main exhaust flow path between the supercharger and the reactor, and the selective catalytic reduction system described above.

According to an embodiment of the present invention, a selective catalytic reduction system and a power device including the same can maximize the utilization efficiency of the overall energy consumed to generate a reducing agent and reduce nitrogen oxides contained in exhaust gas.

1 is a block diagram of a power unit including a selective catalytic reduction system according to an embodiment of the present invention.
2 and 3 are configuration diagrams showing the operating state of the power unit including the selective catalytic reduction system of FIG.
4 is a block diagram of a power unit including a selective catalytic reduction system according to a modification of an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily practice. The present invention can be implemented 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. The relative dimensions and proportions of the parts in the figures are shown exaggerated or reduced in size for clarity and convenience in the drawings, and any dimensions are merely illustrative and not limiting. And the same reference numerals are used to indicate similar features in the same structures, elements, or parts appearing in two or more drawings.

The embodiments of the present invention specifically represent ideal embodiments of the present invention. As a result, various variations of the illustration are expected. Therefore, the embodiment is not limited to a specific form of the illustrated area, and includes, for example, modification of the form by manufacturing.

Hereinafter, a selective catalytic reduction (SCR) system 201 according to an embodiment of the present invention and a power device 101 including the same will be described with reference to FIGS. 1 to 3. 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, but in some cases, an existing installed engine in use ( 100) may be installed ex post to reduce nitrogen oxides (NOx) contained in the exhaust gas. Specifically, the selective catalytic reduction system 201 according to an embodiment of the present invention to improve the eco-friendly performance of an existing engine 100 installed during the repair and maintenance of a transportation means such as a ship or a vehicle or a land or marine plant Additional installations are possible.

1 to 3, the 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 flow path ( 610), the supercharger 150, the reactor 300, the turbocharger bypass flow path 620, the reducing agent injection unit 570, the decomposition chamber 500, the branch flow path 630, the external air supply flow path 640, the blower 410 ), And a heating device 420.

In addition, 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 turbocharger bypass valve 720, a backflow prevention valve 770, a flow control valve ( 710, a first temperature sensor 811, a first flow meter 812, a second flow meter 822, a second temperature sensor 821, and a control unit 700 may be further included.

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

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

The exhaust receiver 180 evenly relieves the exhaust gas of the exhausted engine 100 with an unbalanced pressure due to the cylinder reciprocating motion of the engine 100.

In one embodiment of the present invention, the exhaust gas emitted by the engine 100 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 150. For example, the exhaust gas that has passed through the supercharger 150 may have a temperature lower than 150 degrees Celsius and less than 250 degrees Celsius.

The main exhaust flow path 610 is connected to the exhaust port of the engine 100 to discharge 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 flow path 610 sequentially connects the engine 100, the supercharger 150, and the reactor 300, which will be described later. As such, the main exhaust flow path 610 supplies exhaust gas of the engine 100 that has passed through the supercharger 150 to the reactor 300.

The reactor 300 is installed on the main exhaust flow path 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 nitrogen oxide (NOx) contained in the exhaust gas with a reducing agent, thereby reducing the nitrogen oxide (NOx) to nitrogen and water vapor. At this time, ammonia (NH ₃ ) may be used as a final reducing agent to be reduced by reacting with nitrogen oxide (NOx).

The catalyst can be made of various 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 active temperature refers to a temperature at which the catalyst is not poisoned and can stably reduce nitrogen oxides. When the catalyst reacts outside the active temperature range, the efficiency is lowered while the catalyst is poisoned.

Specifically, the poisoning substance poisoning the catalyst may include one or more of ammonium sulfate ((NH ₄ ) ₂ SO ₄ ) and ammonium hydrogen sulfite (Ammonium bisulfate, NH ₄ HSO ₄ ). The catalyst poisoning substance is adsorbed on the catalyst, thereby reducing the activity of the catalyst. Since the catalyst poisoning substance decomposes at a relatively high temperature, the catalyst can be regenerated by heating the catalyst.

In addition, the housing of the reactor 300, for example, may be made of stainless steel (stainless steel) as a material.

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

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

Specifically, the reducing agent injection unit 570 may inject ammonia (NH ₃ ) toward the exhaust gas moving 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, 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 reducing agent demand that varies depending on the load of the engine 100. That is, the urea supply unit 550 may be supplied in accordance with the reducing agent demand under the control of the control unit 700 to be described later.

The turbocharger bypass flow path 620 diverges from the main exhaust flow path 610, bypasses the supercharger 150, and then joins the main exhaust flow path 610 again. That is, since the exhaust gas moving through the supercharger bypass flow path 620 does not pass through the supercharger 150, it has a relatively high temperature in comparison with the exhaust gas that has passed through the supercharger 150. The turbocharger bypass flow path 620 may be connected to the exhaust receiver 180, as shown in FIG. 1.

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

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

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

In addition, the turbocharger bypass valve 720 may also be used to supply exhaust gas to the decomposition chamber 500 through the branch flow path 630, which will be described later.

When the combustion pressure and the heat load in the combustion chamber of the engine 100 increase above the allowable value, the turbocharger bypass valve 720 is opened to supply a portion of the exhaust gas to the turbocharger bypass flow path 620 and supply it to the turbocharger 150 Reduce the flow rate of exhaust gas. Accordingly, as the pressure of the compressed air supplied to the engine 100 by the supercharger 150 is reduced, the combustion pressure in the combustion chamber of the engine 100 may be adjusted.

As such, the turbocharger bypass valve 720 may be operated independently of the flow control valve 710, which will be described later.

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

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

The flow control valve 710 controls the flow rate of the exhaust gas moving 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 the branch points of the turbocharger 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.

Thus, in one embodiment of the present invention, the amount of heat supplied to the decomposition chamber 500 through the branch flow path 630 with temperature information and flow rate information measured by the first temperature sensor 811 and the first flow meter 812 Can be calculated. In addition, the opening rate of the flow control valve 710 may be adjusted to track the amount of heat required to generate the ammonia as a reducing agent by hydrolyzing the calculated amount of urea as a reducing agent precursor in the decomposition chamber 500.

In this way, the flow control valve 710 is supplied to the decomposition chamber 500 through the branch flow path 630 to generate the amount of heat required to generate the reducing agent in the decomposition chamber 500, the turbocharger bypass flow path 620 according to the calculated amount of heat ), It is possible to adjust the flow rate of the exhaust gas that is branched to the branch flow path 630.

In addition, from the information obtained from the first temperature sensor 811 and the first flow meter 812, the amount of heat supplied to the decomposition chamber 500 through the branch flow path 630 is calculated, and the calculated amount of heat is decomposed to generate a reducing agent. When the amount of heat required in the chamber 500 is exceeded, the flow rate of the exhaust gas moving to the branch flow path 630 may be reduced by adjusting the flow control valve 630.

That is, when the exhaust gas moving along the turbocharger bypass flow path 620 remains after supplying 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 is the branch flow path ( It moves along the supercharger bypass flow path 620 without turning toward 630 and rejoins the main exhaust flow path 610.

As described above, the exhaust gas that has joined the main exhaust channel 610 through the turbocharger bypass channel 620 is combined with the exhaust gas that has decreased in temperature through the turbocharger 150 to increase the temperature of the exhaust gas flowing into the reactor 300. It can be heated.

The temperature of the exhaust gas that has passed through the supercharger 150 may be lowered to 150 degrees Celsius or more and less than 250 degrees Celsius, as described above. When the relatively low temperature flue gas enters the reactor 300, the activity of the catalyst This may degrade or poison the catalyst.

That is, the exhaust gas that has joined the main exhaust channel 610 via the turbocharger bypass channel 620 may increase the exhaust gas flowing into the reactor 300 to maintain the activity of the catalyst and suppress poisoning of the catalyst.

The outside air supply passage 640 supplies outside air to the decomposition chamber 500. That is, the external air supply flow path 640 is branched from the turbocharger bypass flow path 620 and supplies air other than exhaust gas supplied through the branch flow path 630 to the decomposition chamber 500.

The blower 410 and the heating device 420 are installed on the outside air supply flow path 640. The blower 410 sucks in the outside air through the outside air supply passage 640. And 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 installed on the outside air supply flow path 640 to prevent the exhaust gas moving through the branch flow path 630 to the decomposition chamber 500 from flowing back to the outside air supply flow path 640.

According to an embodiment of the present invention, 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, and the calculated amount of heat If it 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 the amount of heat to the decomposition chamber 500 through the external air supply passage 640. have.

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

On the other hand, unlike one embodiment of the present invention, if the heating device 420 is installed in the branch flow path 630, the oxygen concentration of the exhaust gas moving along the branch flow path 630 is lean, such as a heating device 420 such as a burner. ).

The second flow meter 822 is installed on the outside air supply flow path 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 may be installed on the outside air supply flow path 640 behind the heating device 420. The second temperature sensor 821 measures the temperature of the outside air that has passed through the heating device 420.

Accordingly, in one embodiment of the present invention, the second temperature sensor 821 and the second flowmeter 822 are supplied to the decomposition chamber 500 through the outside air supply flow path 640 with the temperature information and the flow rate information measured Calorie can be calculated.

And in one embodiment of the present invention, the sum of the amount of heat supplied through the branch flow path 630 and the amount of heat supplied through the external air supply flow path 640 follows the amount of heat required to generate the reducing agent in the decomposition chamber 500 So that the operation of the blower 410 and the heating device 420 can be adjusted.

The control unit 700 receives and receives information from the first temperature sensor 811, the first flow meter 812, the second temperature sensor 821, and the second flow meter 822, opening and closing the flow control valve 710 ( 410) and the operation of 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 flow path 630 and the amount of heat supplied to the decomposition chamber 500 through the external air supply flow path 640, and the calculated heat amount It is possible to control the flow control valve 710 and the blower 410 and the heating device 420 so that the sum of 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 is followed. have.

In addition, the control unit 700 may control the urea supply unit 550 that supplies urea to the decomposition chamber 500 according to the amount of reducing agent required in consideration of the load fluctuation of the engine 100.

By such a configuration, the power unit 101 including the selective catalytic reduction system 201 according to an embodiment of the present invention uses total energy consumed to generate a reducing agent and reduce nitrogen oxides contained in exhaust gas. Efficiency can be maximized.

Specifically, according to an embodiment of the present invention, after discharging from the engine 100 through the supercharger bypass flow path 620 and the branch flow path 630, the thermal energy of the exhaust gas before passing through the supercharger 150 is decomposed chamber It can be utilized to generate a reducing agent at (500).

In addition, since the vessel is used in various climatic regions, the amount of reducing agent required varies depending on load fluctuations and environmental changes of the engine 100, and the decomposition chamber (through the turbocharger bypass flow path 620 and the branch flow path 630) The amount of heat supplied to 500) also varies.

However, according to an embodiment of the present invention, the amount of heat supplied to the decomposition chamber 500 through the turbocharger bypass flow path 620 and the branch flow path 630 and the external air supply flow path 640 to the decomposition chamber 500 Flow rate control valve 710 and blower 410 to calculate the amount of heat supplied, and to track the amount of heat required to generate the ammonia as a reducing agent by hydrolyzing the urea, the reducing agent precursor, in the decomposition chamber 500 ) And the heating device 420 can be adjusted. That is, it is possible to maximize the utilization efficiency of the overall energy consumed in order to reduce the nitrogen oxides contained in the exhaust gas and to generate a reducing agent even in the load fluctuations and environmental changes of the engine 100.

In addition, as shown in FIG. 4, according to a modification of an embodiment of the present invention, the power unit 102 including the selective catalytic reduction system 202 includes a first flow control valve 711 and a second flow control valve A flow control valve comprising 712 is used.

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

The second flow control valve 712 is installed on the branch flow path 630.

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

Hereinafter, an operating 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 FIGS. 1 to 3.

As shown in FIG. 1, the control unit 700 has the temperature information and the flow rate information measured by the first temperature sensor 811 and the first flow meter 812 to the decomposition chamber 500 through the branch flow path 630. Calculate the amount of heat supplied.

In addition, when the calculated amount of heat satisfies the amount of heat required to generate the reducing agent in the decomposition chamber 500, the control unit 700 does not operate the blower 410 and the heating device 420. That is, according to an embodiment of the present invention, it is possible to prevent unnecessary waste of energy.

Next, as shown in FIG. 2, the control unit 700 has the temperature information and the flow rate information measured by the first temperature sensor 811 and the first flow meter 812 through the branch flow path 630 to decompose the chamber 500 ) To calculate the amount of heat supplied to, and the opening amount of the flow control valve 710 is adjusted so that the calculated amount of heat 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 rate control valve 710 to reduce the flow rate of the exhaust gas moving to the branch flow path 630.

And the remaining exhaust gas corresponding to the amount of heat remaining even after supplying the required amount of heat to the decomposition chamber 500 is moved to the main exhaust flow path 610 by moving along the supercharger bypass flow path 620 without going to the branch flow path 630. To join.

As described above, the exhaust gas that has joined the main exhaust channel 610 through the turbocharger bypass channel 620 is combined with the exhaust gas that has decreased in temperature through the turbocharger 150 to increase the temperature of the exhaust gas flowing into the reactor 300. It can be heated.

Next, as shown in FIG. 3, the control unit 700 has the temperature information and the flow rate information measured by the first temperature sensor 811 and the first flow meter 812 through the branch flow path 630 to decompose the chamber 500 ) To calculate the amount of heat supplied, and if the calculated amount of heat 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 are operated to open the external air supply flow path 640. Through the additional supply of heat to the decomposition chamber 500.

At this time, the control unit 700 calculates the amount of heat supplied to the decomposition chamber 500 through the external air supply flow path 640 from the information obtained from the second temperature sensor 821 and the second flow meter 822, and the branch flow path 630 ) The operation of the blower 410 and the heating device 420 so that the sum of the amount of heat supplied through 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 degree can be controlled.

By such an operation, the power unit 101 including the selective catalytic reduction system 201 according to an embodiment of the present invention uses total energy consumed to generate a reducing agent and reduce nitrogen oxides contained in exhaust gas. Efficiency can be maximized.

Although the embodiments of the present invention have been described 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 implemented in other specific forms without changing its technical spirit or essential features. will be.

Therefore, the embodiments described above are to be understood in all respects as illustrative and not restrictive, and the scope of the present invention is indicated by the following claims, and the meaning and scope of the claims and It should be construed that any altered or modified form derived from the equivalent concept is included in 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
570: reducing agent injection unit
610: main exhaust flow path
620: supercharger bypass euro
630: Quarter Euro
640: external supply flow path
700: control
710: flow control valve
720: supercharger bypass valve
770: non-return valve
811: first temperature sensor
812: first flow meter
821: second temperature sensor
822: second flow meter

Claims (6)

An engine, a supercharger supplying compressed air to the engine, an exhaust receiver disposed between the engine and the supercharger to receive exhaust gas discharged from the engine, and a main exhaust for discharging exhaust gas of the engine to the outside In the selective catalytic reduction system for reducing the nitrogen oxides (NOx) contained in the exhaust gas discharged from the power unit including a flow path,
A reactor installed on the main exhaust passage;
A reducing agent injection unit installed on the main exhaust passage to inject a reducing agent into the exhaust gas moving to the reactor;
A branch flow path connected to the exhaust receiver and connected to the reducing agent injection part, the first end being branched from a turbo bypass path connected to the main exhaust flow path behind the supercharger by bypassing the supercharger;
A decomposition chamber for receiving a reducing agent precursor to decompose the reducing agent precursor into heat to generate a reducing agent for reducing nitrogen oxides and installed on the branch flow path;
An outside air supply flow path supplying outside air to the branch flow path;
A blower installed on the outside air supply passage to suck outside air;
A burner for heating the outside air sucked by the blower and supplying thermal energy necessary for the decomposition chamber;
A first flow control valve installed between a branch point of the turbocharger bypass flow path and the branch flow path, and a confluence point of the turbocharger bypass flow path and the main exhaust flow path;
A second flow control valve installed on the branch flow path; And
A first temperature sensor and a first flow meter installed on the branch flow path
Selective catalytic reduction system comprising a. According to claim 1,
The first flow rate control valve and the first flow control valve are configured such that the sum of the amount of heat supplied through the branch flow path and the amount of heat supplied through the outside air flow path follows the amount of heat required to decompose the reducing agent precursor in the decomposition chamber to generate the reducing agent. 2 Control unit that controls the opening degree of the flow control valve and the degree of operation of the blower and the burner
Selective catalytic reduction system comprising a. According to claim 2,
The control unit calculates the amount of heat supplied to the decomposition chamber through the branch flow path from information obtained from the first temperature sensor and the first flow meter, and when the calculated amount of heat exceeds the amount of heat required to generate the reducing agent, the flow rate By controlling a control valve to reduce the flow rate of the exhaust gas moving to the branch flow path, and when the calculated heat amount is lower than the heat amount required to generate the reducing agent in the decomposition chamber, the blower and the burner are operated to the decomposition chamber. Selective catalytic reduction system characterized in that the additional supply of heat. According to claim 3,
A second temperature sensor installed on the outside air supply passage and measuring the temperature of the outside air that has passed through the burner; And
A second flow meter installed on the outside air supply flow path and measuring the flow rate of the outside air sucked by the blower
Further comprising,
The control unit is a selective catalytic reduction system, characterized in that for calculating the amount of heat supplied to the decomposition chamber through the external air supply passage from the information obtained from the second temperature sensor and the second flow meter. An engine that discharges exhaust gas containing nitrogen oxides (NOx);
A supercharger supplying compressed air to the engine;
An exhaust receiver disposed between the engine and the supercharger to receive exhaust gas discharged from the engine;
A main exhaust flow path for discharging the exhaust gas of the engine to the outside;
A turbocharger bypass flow path connected to the main exhaust flow path between the supercharger and the reactor, one end connected to the exhaust receiver and the other end bypassing the supercharger; And
Selective catalytic reduction system according to any one of claims 1 to 4
Power device comprising a. delete

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