KR20200009382A - Selective catalytic reduction system - Google Patents

Abstract

The present invention relates to a selective catalytic reduction system for reducing nitrogen oxide contained in exhaust gas discharged from an engine. The selective catalytic reduction system according to an embodiment of the present invention includes: a reactor embedding a catalyst for reducing the nitrogen oxide contained in the exhaust gas; a soot blower that ejects a fluid toward the catalyst to remove foreign matter stuck on the catalyst or to regenerate the catalyst; an air supply unit supplying compressed air to the soot blower; and a control unit for adjusting the pressure of the air ejected by the soot blower according to a change in the load of the engine.

Description

Selective Catalytic Reduction System {SELECTIVE CATALYTIC REDUCTION SYSTEM}

The present invention relates to a selective catalytic reduction system used to reduce nitrogen oxides (NOx) contained in exhaust gases.

As industrialization progressed rapidly, the use of fossil fuels such as oil and coal increased. As a result, various harmful gases emitted during the combustion of fossil fuels cause serious air pollution. Representative examples include smog and acid rain.

The main causes of air pollution are sulfur oxides (SOx) and nitrogen oxides (NOx) of exhaust gases emitted from engines of vehicles and ships or from thermal power plants or factories. In recent years, emission awareness for sulfur oxides and nitrogen oxides has been introduced as environmental awareness increases. In particular, a typical catalytic reduction (SCR) system is a representative facility for reducing nitrogen oxides. In the selective catalytic reduction system, the nitrogen gas contained in the exhaust gas and the reducing agent react with each other while passing the exhaust gas and the reducing agent through a reactor in which the catalyst is installed therein, and the reduction process is performed with nitrogen and water vapor.

When such a selective catalytic reduction system is used for ships, the emission of nitrogen oxides (NOx) from marine diesel engines is regulated by the International Maritime Organization (IMO Tier-III). In addition to the need to be able to satisfy the operation of the selective catalytic reduction system is consumed extra energy, there is a demand for an effective operation method with a low-cost, high-efficiency denitrification equipment.

In addition, in order to improve the efficiency of the engine, a turbocharger for supplying new outside air to the engine by turning the turbine to the pressure of the exhaust gas discharged from the engine is widely used in a ship or a vehicle power unit. And exhaust gas through the supercharger is lowered in temperature and pressure.

As such, in the case where a supercharger is used, the selective catalytic reduction system includes a method of arranging a reactor equipped with a catalyst for reducing nitrogen oxides in the rear of the supercharger and a reactor in front of the supercharger, that is, between the engine and the supercharger. Divided into methods.

If a reactor with a built-in catalyst is placed in front of the supercharger, that is, between the engine and the supercharger, the reduction reaction occurs when the temperature of the exhaust gas discharged from the engine is relatively high as compared with the case where the reactor is disposed behind the supercharger. This will happen. Thus, the activity of the catalyst is increased to reduce the amount of catalyst required for nitrogen oxide reduction, but on the contrary, the temperature and pressure of the exhaust gas flowing into the supercharger are reduced, thereby degrading the performance and efficiency of the engine.

In addition, in engines, combustion products, such as soot, generated by incomplete combustion of fuel are exhausted along with the exhaust gas. The soot moves with the exhaust gas and adheres to the catalyst, thereby degrading the performance of the catalyst. When accumulated for a long time, the catalyst blocks the catalyst to narrow or block the exhaust gas, thereby increasing the internal pressure of the reactor in which the catalyst is installed. Thus, by using a soot blower (soot blower) to periodically spray the compressed air to the catalyst, foreign matter including soot trapped in the catalyst is physically removed.

However, when the reactor is disposed in front of the supercharger, the reactor is not only exposed to a relatively high pressure environment but also has a relatively severe pressure fluctuation. For example, a reactor placed in front of the supercharger changes the pressure to approximately 1-5 bar depending on the load of the engine. As such, when the load of the engine is changed, the combustion state of the engine is also changed, and thus the degree of soot is changed. For example, the amount of soot generated during the high load operation of the engine may be further increased.

In this situation in which the load of the engine changes, when the pressure of the air blown by the soot blower is set constant based on the amount of soot generated during the high load operation of the engine, air is unnecessarily consumed during the low load operation. In addition, the injection of high pressure air for a long time through the soot blower can damage the catalyst or shorten the endurance life of the catalyst.

On the contrary, if the pressure of the air blown by the soot blower is set on the basis of the amount of soot generated during low load operation of the engine, the internal pressure of the reactor is not higher than the allowable pressure because the soot generated during high load operation cannot be processed. Ascending situations can occur. As such, when the internal pressure of the reactor is excessively increased, not only the performance of the selective catalytic reduction system may be lowered, but also the performance of the engine for exhausting exhaust gas may be lowered.

The embodiment of the present invention not only minimizes the air consumption by adjusting the pressure of the air injected by the soot blower according to the load change of the engine, but also the high pressure air injected from the soot blower damages the catalyst or the catalyst. Provided is a selective catalytic reduction system capable of suppressing shortening of the service life.

According to an embodiment of the present invention, the selective catalytic reduction system for reducing the nitrogen oxides contained in the exhaust gas discharged from the engine comprises a reactor with a built-in catalyst for reducing the nitrogen oxides contained in the exhaust gas, A soot blower for injecting fluid toward the catalyst to remove the trapped foreign matter or regenerating the catalyst, an air supply for supplying compressed air to the soot blower, and the soot as the load changes in the engine It includes a control unit for adjusting the pressure of the air injected by the blower.

The controller lowers the pressure of air supplied to the soot blower as the load of the engine decreases within a preset maximum pressure and minimum pressure range, and increases the pressure of air supplied to the soot blower as the load of the engine increases. Can be.

The selective catalytic reduction system may further include a regulator installed on an air movement path between the air supply and the soot blower.

The controller may directly receive load information from the engine.

The control unit may further include at least one of the exhaust pressure of the exhaust gas discharged from the engine, the scavenging pressure of the air supplied to the engine, the rotational speed of the engine, and the flow rate of the exhaust gas discharged from the engine. The load can be calculated indirectly.

The selective catalytic reduction system includes a first pressure sensor for measuring the exhaust pressure of the exhaust gas discharged from the engine, a second pressure sensor for measuring the scavenging pressure of the air supplied to the engine, and a rotation speed of the engine. At least one of the engine rotational speed sensor, and a flow meter for measuring the flow rate of the exhaust gas discharged from the engine.

The exhaust gas passing through the reactor is discharged through the supercharger, and the controller may indirectly calculate the load of the engine through at least one of the pressure in front of the supercharger and the rotational speed of the supercharger.

The selective catalytic reduction system may further include at least one of a supercharger shear pressure sensor for measuring the pressure at the front of the supercharger and a supercharger rotational speed sensor for measuring the rotational speed of the supercharger.

The controller may correct the load of the engine indirectly calculated by reflecting the temperature and humidity information of the atmosphere.

The control unit directly receives the load information from the engine, and the control unit may check and compare the load information received directly from the engine with the load information of the engine indirectly calculated.

According to an embodiment of the present invention, the selective catalytic reduction system adjusts the pressure of the air injected by the soot blower according to the load change of the engine to minimize the consumption of air as well as the high pressure air injected from the soot blower. Can impair damaging the catalyst or shortening the endurance life of the catalyst.

1 is a block diagram showing a selective catalytic reduction system according to an embodiment of the present invention.
Figure 2 is a graph showing the pressure change of the air blown by the soot blower in the experimental example according to an embodiment of the present invention.
3 is a graph showing a change in pressure of air injected by the soot blower in the comparative example.

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 may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

It is noted that the figures are schematic and 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 exemplary and not limiting. And the same reference numerals are used to represent similar features in the same structures, elements or parts that appear in more than one figure.

Embodiments of the invention specifically illustrate ideal embodiments of the invention. As a result, various modifications of the drawings are expected. Thus, the embodiment is not limited to the specific form of the illustrated region, and includes, for example, modification of the form by manufacture.

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

Selective catalytic reduction system 101 according to an embodiment of the present invention reduces the nitrogen oxide (NOx) contained in the exhaust gas discharged from the engine 100.

In one example, the engine 100 may be a two-stroke low speed diesel engine for ships. However, one embodiment of the present invention is not limited to the above description, and the engine 100 may be a four-row medium speed diesel engine. In addition, a plurality of engines 100 may be used, in which case a two-stroke low speed diesel engine and a four-row medium speed diesel engine may be mixed. At this time, the two-stroke low-speed diesel engine may be used as the main power source for providing a propulsion to the ship, the four-row medium-speed diesel engine may be used for power generation or auxiliary power source.

In addition, the engine 100 is not necessarily limited to a ship, but may also be a vehicle engine. In addition, various types of engines 100 known to those skilled in the art may be used.

In addition, in one embodiment of the present invention, some or all of the exhaust gas discharged from the engine 100 may pass through the supercharger 150. The supercharger 150 is connected to the exhaust port of the engine 100, and when the turbine 151 is turned to the pressure of the exhaust gas of the engine 100, the compressor 152 compresses new external air to the engine 100 by the force. Supply. Thus, the engine 100 equipped with the supercharger 150 may improve efficiency. The supercharger 150 and the engine 100 are connected to the scavenging line 620, and the air compressed by the supercharger 150 is supplied to the engine 100 through the scavenging line 620.

In addition, in one embodiment of the present invention, the exhaust gas discharged from the engine 100 has a temperature in the range of 200 degrees Celsius to 500 degrees Celsius, the temperature of the exhaust gas may be lowered through the supercharger 150. For example, the exhaust gas passing through the supercharger 150 may be lowered to a temperature of 150 degrees Celsius or more and less than 200 degrees Celsius, and may be lowered at an initial operation of the engine 100.

As shown in FIG. 1, the selective catalytic reduction (SCR) system 101 according to an embodiment of the present invention includes a reactor 300, a soot blower 410, an air supply unit 450, and a controller. And 700.

In addition, the selective catalytic reduction system 101 according to an embodiment of the present invention is a regulator (430), the exhaust passage 610, scavenging line 620, decomposition chamber 500, reducing agent injection unit 510, And a reducing agent supply unit 550.

In addition, the selective catalytic reduction system 101 according to an embodiment of the present invention, the first pressure sensor 710, the second pressure sensor 720, the engine speed sensor 730, the flow meter 750, the supercharger shear pressure It may further include one or more of the sensor 760, and the supercharger rotational speed sensor 770.

The exhaust passage 610 moves the exhaust gas containing nitrogen oxides (NOx). And the exhaust gas moving along the exhaust flow path 610 is discharged to the outside via the reactor 300 to be described later. For example, the exhaust passage 610 may be connected to the exhaust port of the engine 100 to exhaust the exhaust gas discharged from the engine 100.

The reactor 300 is installed on the exhaust flow path 610. That is, the reactor 300 receives exhaust gas containing nitrogen oxides (NOx) through the exhaust flow path 610. In addition, the reactor 300 includes a catalyst 350 for reducing nitrogen oxide (NOx) contained in the exhaust gas. The catalyst 350 promotes the reaction between the nitrogen oxide (NOx) contained in the exhaust gas and the reducing agent to reduce the nitrogen oxide (NOx) to nitrogen and water vapor.

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

The catalyst 350 may be made of various materials known to those skilled in the art, such as zeolite, vanadium, platinum, and the like. In one example, the catalyst 350 may have an active temperature in the range of 200 degrees Celsius to 500 degrees Celsius. Here, the active temperature refers to a temperature at which the catalyst 350 can stably reduce nitrogen oxides without poisoning. If the catalyst 350 reacts outside the active temperature range, the catalyst 350 becomes poisoned and efficiency decreases. For example, if a reduction reaction occurs to reduce nitrogen oxides contained in exhaust gases at relatively low temperatures of more than 150 degrees Celsius and less than 250 degrees Celsius, sulfur oxides (SOx) and ammonia (NH ₃ ) in the exhaust gases react. This produces a catalyst poisoning substance. Specifically, the poisoning material for poisoning the catalyst 350 may include one or more of ammonium sulfate (NH ₄ ) ₂ SO ₄ ) and ammonium bisulfate (NH ₄ HSO ₄ ). The catalyst poisoning substance is adsorbed on the catalyst to lower the activity of the catalyst 350. Since the catalyst poisoning substance decomposes at a relatively high temperature, that is, a temperature in the range of 350 degrees Celsius to 450 degrees Celsius, the catalyst 350 in the reactor 300 may be heated to regenerate the poisoned catalyst 350.

In addition, in one embodiment of the present invention, the reactor 300 may be installed on the exhaust passage 610 in front of the supercharger 150. That is, the reactor 300 may be disposed between the engine 100 and the supercharger 150.

Hereinafter, in the present specification, the front means an upstream direction based on the moving direction of the exhaust gas, and the rear means a downstream direction based on the moving direction of the exhaust gas.

The decomposition chamber 500 is installed on the exhaust passage 610 in front of the reactor 300. The decomposition chamber 500 forms a space for decomposing and vaporizing the reducing agent, and may be omitted depending on the type of the selective catalytic reduction system 101.

The reducing agent injector 510 may be installed in the decomposition chamber 500, the exhaust passage 610 in front of the reactor 300, or the front of the reactor 300 to inject the reducing agent. For example, the reducing agent injector 510 may inject the urea (urea, CO (NH ₂ ) ₂ ) in the form of an aqueous solution to the exhaust gas moving along the exhaust flow path 610.

In one embodiment of the present invention, the aqueous solution of urea (urea, CO (NH ₂ ) ₂ ) sprayed by the reducing agent injection unit 510 corresponds to the reducing agent precursor, ammonia (NH ₃ ) and iso Isocyanic acid (HNCO) is produced, and isocyanic acid (HNCO) can be decomposed back into ammonia (NH ₃ ) and carbon dioxide (CO ₂ ). Finally, the produced ammonia (NH ₃ ) is used as a reducing agent to reduce the nitrogen oxides (NOx) contained in the exhaust gas.

The reducing agent supply unit 500 supplies a reducing agent to be injected by the reducing agent injection unit 510. Since the emission of the exhaust gas discharged from the engine 100 varies according to the load variation of the engine 100, the amount of the reducing agent required to reduce the nitrogen oxide contained in the exhaust gas also varies. Accordingly, the reducing agent supply unit 500 may adjust the supply amount of the reducing agent so that the appropriate amount of the reducing agent may be supplied according to the operating conditions of the engine 100 or the discharge situation of the exhaust gas. In addition, the reducing agent supply unit 500 may provide information on the reducing agent supply flow rate to the control unit 700 to be described later.

Specifically, the reducing agent supply unit 500 is a reducing agent storage tank for storing the reducing agent to be supplied to the reducing agent injection unit 510, a reducing agent supply pump module for supplying the reducing agent stored in the reducing agent storage tank, a flow meter for measuring the supply flow rate, and And a reducing agent supply line for moving the reducing agent. Here, the reducing agent supply pump module may include a pump for reducing agent supply, a filter necessary for installing the pump, a pressure gauge for the pump, a manual valve for the pump, and the like.

A soot blower 410 is inserted into the reactor 300 and installed to inject compressed air toward the catalyst 350. In addition, the soot blower 410 may be a lance type, but is not limited thereto, and the soot blower 410 may be formed in various shapes. The soot blower 410 receives compressed air from the air supply unit 450 to be described later and injects compressed air toward the catalyst 350 of the reactor 300. Air injected from the soot blower 410 may physically remove the foreign matter trapped in the catalyst 350. Here, the foreign matter includes combustion products such as soot generated by incomplete combustion of fuel in the engine 100. Such foreign matter moves with the exhaust gas and adheres to the catalyst 350, thereby degrading the performance of the catalyst 350, and when accumulated for a long time, the catalyst 350 blocks the catalyst 350 so that the movement path of the exhaust gas becomes narrow or occluded. The internal pressure of the reactor 300 is increased. As such, when the internal pressure of the reactor 300 is excessively increased, the performance and lifespan of the selective catalytic reduction system 101 may be reduced, as well as the performance of the engine 100 exhausting the exhaust gas.

In addition, the air injected from the soot blower 410 may be utilized to regenerate the catalyst 350 by removing the poisoned material poisoning the catalyst 350. The air injected from the soot blower 410 to regenerate the catalyst 350 may be at a temperature at which the catalyst poisoning substance can decompose.

In addition, in one embodiment of the present invention, the soot blower 410 is controlled by the pressure of the air to be injected in accordance with the control of the control device 700 to be described later.

The air supply unit 450 may supply compressed air to the soot blower 410. The air supply 450 may be configured in various ways known to those skilled in the art. For example, the supercharger 150 may be used as the air supply 450, or the air supply 450 may be one of a compressed air tank or a compressed air supply pump provided in a ship.

The regulator 430 may be installed on an air movement path between the air supply 450 and the soot blower 410. The regulator 430 adjusts the pressure of air supplied from the air supply unit 450 to the soot blower 410. The control device 700 to be described later may control the air supply unit 450 or the regulator 430 to adjust the pressure of the air injected by the soot blower 410.

The first pressure sensor 710 may measure the exhaust pressure of the exhaust gas discharged from the engine 100. The second pressure sensor 720 may measure the scavenging pressure of the air supplied to the engine 100.

The engine rotation speed sensor 730 may measure the rotation speed of the engine 100. In this case, the engine rotation speed sensor 730 may be built in the engine 100 or installed on the rotation shaft of the engine 100.

The flow meter 750 may measure the flow rate of the exhaust gas discharged from the engine 100.

The supercharger shear pressure sensor 760 may measure the pressure in front of the supercharger 150, that is, the pressure of the exhaust gas flowing into the supercharger 150. The supercharger rotational speed sensor 770 may measure the rotational speed of the supercharger 150. At this time, the supercharger rotational speed sensor 770 may be built in the supercharger 150 or installed on the rotary shaft of the turbine.

In one embodiment of the present invention, the first pressure sensor 710, the second pressure sensor 720, the engine rotational speed sensor 730, the flow meter 750, the supercharger shear pressure sensor 760, and the supercharger rotational speed sensor One or more of 770 may be used, and the rest that is not used may be omitted.

The controller 700 adjusts the pressure of the air injected by the soot blower 410 according to the load variation of the engine 100. Specifically, the controller 700 lowers the pressure of the air supplied to the soot blower 410 as the load of the engine 100 decreases within a preset maximum pressure and minimum pressure range, and as the load of the engine 100 increases. The pressure of the air supplied to the soot blower 410 may be increased. Here, the predetermined maximum pressure and the predetermined minimum pressure not only consider the performance and specifications of the soot blower 410 and the amount of soot generated in the engine 100, but also the overall performance of the selective catalytic reduction system 101 and the engine 100. Can be set in consideration of the impact on the performance of

When the load of the engine 100 increases, soot due to incomplete combustion increases in the exhaust gas discharged from the engine 100. Therefore, in one embodiment of the present invention, as the load of the engine 100 increases, the soot blower 410 increases the pressure of the air injected to effectively remove foreign substances trapped in the catalyst 350, and the load of the engine 100 is increased. As it decreases, the pressure of the air blown by the soot blower 410 may be lowered to minimize unnecessary consumption of air.

In addition, the controller 700 may receive load information directly from the engine 100. And the control unit 700 is the exhaust pressure of the exhaust gas discharged from the engine 100, the scavenging pressure of the air supplied to the engine 100, the rotational speed of the engine 100, and discharged from the engine 100 The load of the engine 100 may be indirectly calculated through at least one of the flow rates of the exhaust gas. In addition, the controller 700 may indirectly calculate the load of the engine 100 through at least one of a pressure in front of the supercharger 150 and a rotation speed of the supercharger 150.

An operating state of the engine 100, that is, load information of the engine 100 may be calculated under various conditions of the exhaust gas. The purge gas and the exhaust gas for each load of the engine 100 have different constant temperature, pressure, flow rate, and the like, and exhibit a constant rotational speed for each load of the engine 100. As such, the load of the engine 100 is correlated with the exhaust pressure, the scavenging pressure, the rotational speed of the engine 100, the flow rate of the exhaust gas, the pressure in front of the supercharger 150, and the rotational speed of the supercharger 150. Based on these information, the load of the engine 100 may be indirectly calculated. For example, when the pressure at the front of the supercharger 150 is increased by the exhaust gas discharged from the combustion chamber of the engine 100, and the pressure at the front of the supercharger 150 is increased, the supercharger 150 supplies the engine 100 to the engine 100. The pressure of air, that is, the scavenging pressure, rises. The increase in pressure and scavenging pressure at the front of the supercharger 150 means that the load of the engine 100 is relatively high, and the decrease in the pressure and scavenging pressure at the front of the supercharger 150 is relatively low in the load of the engine 100. Means. In addition, since the exhaust gas discharged from the engine 100 varies according to the load variation of the engine 100, the load of the engine 100 may be indirectly estimated by measuring the flow rate of the exhaust gas.

In addition, since the discharge amount of the exhaust gas of the engine 100 and the desired flow rate and pressure change according to the temperature and humidity of the atmosphere, the controller 700 indirectly reflects the temperature and humidity information of the atmosphere for more precise control. The calculated load of the engine 100 can be corrected.

In addition, it is most preferable that the control unit 700 receives the load information directly from the engine 100. However, if an error occurs in the engine 100 or an error occurs in a signal for an operating condition of the engine 100, the engine ( An error may occur in the signal of the load information received from 100 and the load of the actual engine 100.

Therefore, the control unit 700 indirectly calculates the load of the engine 100 from various factors generated by the engine 100 actually operating, and load information received directly from the engine 100 and the load information thus calculated. By examining and examining the current state of the engine 100 can be determined more accurately.

That is, according to an embodiment of the present invention, the control unit 700 may use only any one of various methods for determining the operating state of the engine 100, but through the various methods of each of the engine 100 By grasping the driving conditions and checking these, the load of the engine 100 can be more accurately determined.

As described above, the control unit 700 grasps the load information of the engine 100, and relatively lowers the pressure of air injected by the soot blower 410 when the engine 100 is in a low load state, and the engine 100. In this high load state, by increasing the pressure of the air injected by the soot blower 410, the consumption of the air injected by the soot blower 410 is minimized. It is possible to suppress damage or to shorten the endurance life of the catalyst 350, and to prevent the performance of the selective catalytic reduction system 101 and the performance of the engine 100 from being reduced.

By such a configuration, the selective catalytic reduction system 101 according to the embodiment of the present invention adjusts the pressure of the air injected by the soot blower 410 according to the load variation of the engine 100 to minimize the consumption of air. In addition, the high pressure air injected from the soot blower 410 may be suppressed from damaging the catalyst 350 or shortening the endurance life of the catalyst 350. In addition, the performance degradation of the selective catalytic reduction system 101 and the performance degradation of the engine 100 can be prevented.

Hereinafter, with reference to FIG. 2 looks at the experimental example and the comparative example according to an embodiment of the present invention.

Figure 2 shows the change in the pressure of the exhaust gas and the pressure of the air injected by the soot blower according to the load change of the engine in the experimental example. As shown in Fig. 2, the difference P1 between the pressure of the exhaust gas and the pressure of the air blown by the soot blower when the engine is driven at high load is the pressure of the exhaust gas and the air blown by the soot blower when the engine is run at low load. Is very similar or identical to the difference between the pressures of P2.

Figure 3 shows the pressure change of the exhaust gas and the pressure change of the air blown by the soot blower according to the load change of the engine in the comparative example. In the comparative example, the soot blower injects air at a constant pressure. That is, as shown in FIG. 3, even if the load of the engine changes and the pressure of the exhaust gas changes, the pressure of air injected by the soot blower does not change. In addition, the pressure of the air injected by the soot blower is set based on the amount of soot generated during the high load operation of the engine.

Therefore, the difference (P4) between the pressure of the exhaust gas and the pressure of the air injected by the soot blower when the engine is driven at a low load, rather than the difference (P3) between the pressure of the exhaust gas and the pressure that the soot blower injects when the engine is running at high loads. You can see that it is much larger. That is, in the experimental example, it is possible to reduce the air consumption by the area indicated by the dot in FIG. 3 than the comparative example.

In the experimental example, since the pressure of the air injected by the soot blower is not always kept high, it is possible to suppress the catalyst from being damaged by the high pressure air.

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

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

100: engine
101: selective catalytic reduction system
150: supercharger
151: turbine
152: compressor
300: reactor
350: catalyst
410: suit blower
430: recurator
450: compressed air supply
500: decomposition chamber
510: reducing agent injection unit
550; Reductant Supply Unit
610: exhaust flow path
620: the desired line
700: control unit
710: first pressure sensor
720: second pressure sensor
730: engine speed sensor
750: flow meter
760: supercharger shear pressure sensor
770: Supercharger rotational speed sensor

Claims (10)

In the selective catalytic reduction system for reducing the nitrogen oxide contained in the exhaust gas discharged from the engine,
A reactor incorporating a catalyst for reducing nitrogen oxides contained in the exhaust gas;
A soot blower for injecting fluid toward the catalyst to remove foreign substances trapped in the catalyst or to regenerate the catalyst;
An air supply unit supplying compressed air to the soot blower; And
Control unit for adjusting the pressure of the air injected by the soot blower in accordance with the load change of the engine
Selective catalytic reduction system comprising a. The method of claim 1,
The control unit lowers the pressure of air supplied to the soot blower as the load of the engine decreases within a preset maximum pressure and minimum pressure range, and increases the pressure of air supplied to the soot blower as the load of the engine increases. Selective catalytic reduction system, characterized in that. The method of claim 1,
And a regulator installed on an air movement path between the air supply and the soot blower. The method of claim 1,
The control unit is a selective catalytic reduction system, characterized in that directly receiving the load information from the engine. The method of claim 1,
The controller controls the load of the engine through at least one of exhaust pressure of the exhaust gas discharged from the engine, a scavenging pressure of air supplied to the engine, a rotation speed of the engine, and a flow rate of exhaust gas discharged from the engine. Selective catalytic reduction system, characterized in that the indirect calculation. The method of claim 5,
A first pressure sensor measuring exhaust pressure of the exhaust gas discharged from the engine;
A second pressure sensor measuring a scavenging pressure of air supplied to the engine:
An engine rotation speed sensor measuring a rotation speed of the engine; And
Flow meter for measuring the flow rate of the exhaust gas discharged from the engine
Selective catalytic reduction system further comprises one or more of. The method of claim 1,
Exhaust gas passing through the reactor is discharged through a supercharger,
And the control unit indirectly calculates the load of the engine through at least one of the pressure in front of the supercharger and the rotational speed of the supercharger. The method of claim 7, wherein
A supercharger shear pressure sensor for measuring the pressure at the front of the supercharger; And
Supercharger rotational speed sensor for measuring the rotational speed of the supercharger
Selective catalytic reduction system further comprises one or more of. The method according to claim 5 or 7,
The control unit is a selective catalytic reduction system, characterized in that for correcting the load of the engine indirectly calculated by reflecting the temperature and humidity information of the atmosphere. The method according to claim 5 or 7,
The control unit directly receives load information from the engine,
The controller selectively checks the load information received directly from the engine and the load information of the engine calculated indirectly.

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