KR20180120368A - Reaction for selective catalytic reduction - Google Patents

Abstract

The present invention relates to a reactor for selective catalytic reduction. According to an embodiment of the present invention, the reactor for selective catalytic reduction comprises: a reactor main body connected to an exhaust flow path in which exhaust gas flows; a catalytic module being able to swivel in the reactor main body about a swiveling shaft installed at the inner wall of the reactor main body; and a swiveling driving portion swiveling the catalytic module.

Description

[0001] REACTION FOR SELECTIVE CATALYTIC REDUCTION [0002]

The present invention relates to a selective catalytic reduction reactor, and more particularly, to a selective catalytic reduction reactor for reducing nitrogen oxides (NOx) contained in exhaust gases.

As industrialization has progressed rapidly, the use of various fossil fuels such as petroleum and coal has increased. As a result, various harmful gases emitted from the combustion process of fossil fuels cause serious air pollution. Typical examples are smog phenomenon and acid rain.

The main cause of air pollution is sulfur oxides (SOx) and nitrogen oxides (NOx) of exhaust gas emitted from engines of vehicles and ships, thermal power plants and factories.

Recently, as the awareness of environmental conservation has increased, regulations on emission of sulfur oxides and nitrogen oxides have been introduced.

In particular, there is a selective catalytic reduction (SCR) system as a typical facility for reducing nitrogen oxides.

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.

When this selective catalytic reduction system is used on ships, the emission of NOx from marine diesel engines is controlled by the International Maritime Organization's International Standard for the Prevention of Air Pollution (IMO Tier-III) It is required to use an efficient denitrification system with a low cost and high efficiency.

That is, if the concentration of nitrogen oxides contained in the exhaust gas satisfies the environmental regulation according to the engine operating conditions, or if the ship is operated outside the regulated area, the operation of the selective catalytic reduction system should be stopped to improve the energy utilization efficiency .

Thus, when it is not necessary to operate the selective catalytic reduction system, the exhaust gas is transferred to the bypass flow path to bypass the reactor provided with the catalyst for reducing nitrogen oxides.

In addition, the selective catalytic reduction system mainly utilizes a high-temperature active catalyst having an active temperature within the range of 250 ° C. to 350 ° C. in consideration of economical efficiency and radioactivity regulation. Here, the activation temperature refers to a temperature at which the catalyst can be stably reduced without being poisoned.

However, when the catalyst reacts outside the activation temperature range, the activity of the catalyst is continuously deteriorated as the catalyst is poisoned. Particularly, when exhaust gas having a relatively low temperature of less than 250 ° C. is introduced into a reactor equipped with a high-temperature active catalyst, sulfur oxide (SOx) of exhaust gas reacts with ammonia (NH ₄ ) do. Catalyst poisoning material may comprise one or more of ammonium sulfate _{(Ammonium sulfate, (NH4) 2} SO 4) and ammonium bisulfite _{(Ammonium bisulfate, NH 4 HSO 4} ).

Such a catalyst poisoning material is adsorbed on the catalyst to lower the activity of the catalyst. Therefore, in order to increase the efficiency of the catalyst and minimize the loss due to maintenance, it is required to keep the temperature of the catalyst within the active temperature range.

However, in the case of a low speed diesel engine for ships, it is difficult to completely avoid the poisoning of the catalyst because the emission amount of the exhaust gas changes according to the load change of the diesel engine and the climate environment in which the ship is operating also affects the selective catalytic reduction reaction.

Therefore, when the catalyst is poisoned during the operation of the ship and the required performance is not achieved, the catalyst is regenerated. Even in the case of regenerating the catalyst, the exhaust gas is transferred to the bypass flow path to bypass the reactor provided with the catalyst for reducing nitrogen oxides.

However, in the case of a ship or a vehicle, it is difficult to provide a bypass flow path separately from an exhaust flow path through a reactor in a selective catalytic reduction system installed in a ship or a vehicle.

Embodiments of the present invention provide a selective catalytic reduction reactor having improved space utilization efficiency by pivoting a catalyst module within a reactor body.

Embodiments of the present invention also provide selective catalytic reduction reactors that can easily regenerate the catalyst module within the reactor body.

According to an embodiment of the present invention, a selective catalytic reduction (SCR) reactor includes a reactor main body connected to an exhaust flow path through which exhaust gas moves, A swivelable catalyst module, and a swivel driving unit for swiveling the catalyst module.

At least one or more pivotal shafts may be provided on each of the opposite inner and outer walls of the reactor body, and one or more pairs of the catalytic modules may be connected to the pivot shaft.

The swivel driving unit may include a traction wire connected to the other side opposite to the one side of the catalyst module connected to the pivot shaft, and a driving motor provided on the outside of the reactor main body to wind the tow wire.

In the selective catalytic reduction reactor, the catalyst module may include a first position having a length in a direction crossing the moving direction of the exhaust gas, and a second position having a length in a direction parallel to the moving direction of the exhaust gas, And a second position having a second end.

The selective catalytic reduction reactor may further include a stopper provided to allow the catalyst module to swing from the second position to the first position and stop at a predetermined position.

The reactor body has a length in the longitudinal direction and the exhaust gas can move up and down. And the catalyst module moves from the first position to the second position by its own weight, and the catalyst module can move from the second position to the first position by the swivel driving part.

The selective catalytic reduction reactor may further include a soot blower for injecting a high-pressure fluid toward the catalyst module when the catalyst module is located at the second position.

The selective catalytic reduction reactor may further include a heating device for heating the catalyst module when the catalyst module is located in the second position.

The heating device may be an electric heater.

Further, the heating device may include a recirculation flow path for moving the exhaust gas branched from the exhaust flow path in the rear of the reactor body toward the catalyst module located at the second position, and a burner installed on the recirculation flow path have.

In addition, the selective catalytic reduction reactor may further include a circulation blower installed on the recirculation flow path.

According to the embodiment of the present invention, the selective catalytic reduction reactor can improve the space utilization efficiency by turning the catalyst module inside the reactor body.

Further, according to embodiments of the present invention, the selective catalytic reduction reactor can easily regenerate the catalyst module inside the reactor body.

1 is a configuration diagram of a selective catalytic reduction reactor according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing the operating state of the selective catalytic reduction reactor of FIG. 1. FIG.
3 is a block diagram of a selective catalytic reduction reactor according to a second embodiment of the present invention.
FIG. 4 is a configuration diagram illustrating an operation state of the selective catalytic reduction reactor of FIG. 3;

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In addition, in the various embodiments, components having the same configuration are denoted by the same reference symbols in the first embodiment. In the other embodiments, only components different from those in the first embodiment will be described.

The drawings are schematic and not drawn to scale. The relative dimensions and ratios of the parts in the figures are 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.

Hereinafter, the selective catalytic reduction reactor 101 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG.

The selective catalytic reduction (SCR) reactor 101 according to the first embodiment of the present invention is used to reduce nitrogen oxides (NOx) contained in the exhaust gas discharged from the power unit. For example, the power unit may be a diesel engine used as a main power source for supplying a propulsion force to a ship. Further, the diesel engine may be a two-stroke low-speed diesel engine for marine use.

However, the first embodiment of the present invention is not limited thereto. The power unit may be an internal combustion engine for a plant or an automotive engine. That is, various types of engines known to those skilled in the art can be used as the power unit.

Exhaust gas containing nitrogen oxides (NOx) discharged from the power unit moves through the exhaust gas passage 610. That is, the exhaust passage 610 is connected to the exhaust port of the diesel engine, which is a power unit, to exhaust the exhaust gas of the diesel engine.

1, the selective catalytic reduction reactor 101 according to the first embodiment of the present invention includes a reactor main body 300, a catalyst module 400, and a swivel drive unit 430. As shown in FIG.

The selective catalytic reduction reactor 101 according to the first embodiment of the present invention may further include a stopper 450, a soot blower 800, and a heating device 701.

The reactor main body 300 is connected to an exhaust gas passage 610 through which the exhaust gas moves. Specifically, the reactor main body 300 has an inlet 301 through which exhaust gas flows and an outlet 309 through which the exhaust gas is discharged. The inlet 301 and the outlet 309 of the reactor main body 300 are connected to the exhaust- (610). That is, the exhaust gas moving along the exhaust passage 610 flows into the reactor main body 300 through the inlet port 301, is discharged through the exhaust port 309, and then moves along the exhaust gas passage 610 again.

In the first embodiment of the present invention, a pivot shaft 430 is provided on the inner wall of the reactor main body 300. At least one or more pivotal shafts 430 may be provided on opposite inner walls of the reactor body 300.

The catalyst module 400 may be pivoted in the reactor body 300 around a pivot shaft 430 installed on the inner wall of the reactor body 300. In addition, the at least one pair of the catalyst modules 400 may be connected to the pivot shaft 430 installed at one or more of the opposite side inner walls of the reactor body 300.

As shown in FIG. 1, the catalyst module 400 has a first position having a length in a direction intersecting with the direction of movement of the exhaust gas, and a first position having a length in a direction close to the inner wall of the reactor main body 300 And a second position having a length in a direction parallel to the moving direction of the exhaust gas.

Also, a plurality of catalyst modules 400 installed inside the reactor body 300 may be arranged in a multi-layer structure with respect to the moving direction of the exhaust gas. And the catalyst module 400 includes a catalyst for a selective catalytic reduction reaction.

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.

For example, when a reduction reaction occurs to reduce the nitrogen oxides contained in the exhaust gas at a relatively low temperature of not less than 150 ° C. and less than 250 ° C., the sulfur oxides (SOx) of the exhaust gas and ammonia (NH ₃ ) The catalyst poisoning material is produced.

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 is decomposed at a relatively high temperature, that is, at a temperature within a range of from 350 degrees Celsius to 450 degrees Celsius, the catalyst in the reactor can be heated to regenerate the poisoned catalyst.

Ammonia (NH ₃ ) is used as the reducing agent, which can be supplied in the form of an aqueous solution of urea (CO (NH ₂ ) ₂ ) which is a reducing agent precursor. Since ammonia itself is not easily stored and transported as a pollutant, it is common to use a stable urea aqueous solution. An aqueous solution of urea, CO (NH ₂ ) ₂ ) is hydrolyzed or pyrolyzed to produce ammonia (NH ₃ ) and isocyanic acid (HNCO). And isocyanate (HNCO) decomposes again into ammonia (NH ₃ ) and carbon dioxide (CO ₂ ). That is, it decomposes urea to produce ammonia as a reducing agent that reacts with nitrogen oxides.

The stopper 450 is provided to allow the catalyst module 400 to swing from the second position to the first position and stop at the predetermined position.

The swivel driving unit 500 turns the catalytic module 400. The swing drive unit 500 includes a traction wire 510 connected to the other side opposite to one side of the catalyst module 400 connected to the pivot shaft 430 and a traction wire 510 provided outside the reactor body 300, (Not shown). At this time, the driving motor 550 may include a traction roller.

However, the first embodiment of the present invention is not limited to the above, and the swing drive unit 500 may swing the catalyst module 400 by various methods known to those skilled in the art. That is, the swing drive unit 500 may rotate the pivot shaft 430 provided in the reactor main body 300 to swing the catalyst module 400.

Further, in the first embodiment of the present invention, the reactor body 300 has a length in the longitudinal direction and the exhaust gas can move in the up and down direction. In Figs. 1 and 2, the exhaust gas moves upward and downward. The catalytic module 400 moves from the first position to the second position by its own weight and the catalytic module 400 can be moved from the second position to the first position by the swivel driving part 500. That is, when the catalyst module 400 moves from the second position to the first position, the swing drive unit 500 pulls up the catalyst module 400.

The soot blower 800 may inject a high-pressure fluid toward the catalyst module 400 when the catalyst module 400 is positioned at the second position. Here, the fluid may include at least one of a gas and a liquid. The soot blower 800 can perform both the role of removing the foreign material impregnated into the catalyst by spraying the fluid and regenerating the poisoned catalyst.

In addition, when the catalyst module 400 is located at the second position, a plurality of through holes connected to the soot blower 800 may be formed on the wall of the reactor body 300 adjacent to the catalyst module 400.

The soot blower 800 can receive the high-pressure fluid from the separately provided compressed air supply unit 850. For example, the compressed air supply unit 850 may be a compressed air storage tank, a compressed air supply unit used for a ship, or an engine supercharger.

The heating device 701 may heat the catalyst module 400 when the catalyst module 400 is in the second position. The heating device 701 can regenerate the catalyst by heating the catalyst module 400 to remove poisoning substances that poison the catalyst. Also, the heating device 701 may preheat the catalyst.

Further, according to the first embodiment of the present invention, the heating device 701 may be an electric heater. That is, when the catalyst module 400 is located in the second position, an electric heater, which is a heating device 701, may be provided adjacent to the wall of the reactor body 3000 adjacent to the catalyst module 400.

With such a construction, the selective catalytic reduction reactor 101 according to the first embodiment of the present invention can improve the space utilization efficiency by turning the catalyst module 400 in the reactor main body 300.

Specifically, when performing the operation of reducing nitrogen oxide through the selective catalytic reduction reaction, the catalyst module 400 is turned and moved to the first position.

On the other hand, when the operation for reducing nitrogen oxides is not performed or the catalyst is regenerated or preheated, the catalyst module 400 is pivoted and moved to the second position.

Therefore, according to the first embodiment of the present invention, there is no need to separately form a bypass flow path for bypassing the selective catalytic reduction reactor 101.

In addition, according to the first embodiment of the present invention, the selective catalytic reduction reactor 101 can easily regenerate or preheat the catalyst after the second positioning of the catalyst module 400 in the reactor main body 300 by pivoting have.

Hereinafter, the selective catalytic reduction reactor 102 according to the second embodiment of the present invention will be described with reference to FIGS. 3 and 4. FIG.

3 and 4, the selective catalytic reduction reactor 102 according to the second embodiment of the present invention may include a burner 720 and a recycle passage 760 as a heating device 702. [

The recirculation flow path 760 moves a part of the exhaust gas branched from the exhaust flow path 610 behind the reactor main body 300 toward the catalyst module 400 located at the second position. The burner 720 is installed on the recirculation passage 760 to raise a part of the exhaust gas moving along the recirculation passage 760.

The burner 720 may be a variety of burners known to those skilled in the art, such as an oil burner or a plasma burner.

As described above, in the second embodiment of the present invention, a part of the exhaust gas heated by the burner 720 can be supplied to the catalyst module 400 located at the second position to regenerate or preheat the catalyst.

In this specification, the term forward refers to the upstream direction with respect to the direction of movement of the fluid, and the term " rear " refers to the downstream direction with respect to the direction of movement of the fluid.

In addition, the selective catalytic reduction reactor 102 according to the second embodiment of the present invention may further include a circulation blower 950. The circulation blower 950 is installed on the recirculation flow path 760 and forcibly moves the exhaust gas along the recirculation flow path 760 when the burner 720 is to be operated.

The reducing agent supply passage 780 branching from the recirculation passage 760 and joining the exhaust passage 610 in front of the reactor main body 300 may be provided in the recirculation passage 760, May be installed. In the decomposition chamber 900, a urea aqueous solution, which is a reducing agent precursor, may be injected.

The urea aqueous solution injected into the decomposition chamber 900 is decomposed in the decomposition chamber 900 to generate ammonia as a reducing agent and the reducing agent moves along the reducing agent supply passage 780 and is supplied to the exhaust passage 610. The reducing agent flows into the reactor main body 300 while being mixed with the exhaust gas in the exhaust gas passage 610.

In addition, a control valve 770 may be provided in the recirculation passage 760 and the reducing agent supply passage 780 to control the moving direction of the fluid.

With such a construction, the selective catalytic reduction reactor 102 according to the second embodiment of the present invention can improve the space utilization efficiency by turning the catalyst module 400 in the reactor main body 300.

Specifically, when performing the operation of reducing nitrogen oxide through the selective catalytic reduction reaction, the catalyst module 400 is pivotally moved to the first position, and the catalyst unit 400 is moved to the first position by using the heating device 702, And supplies a reducing agent to the exhaust flow path 610.

On the other hand, when the operation for reducing nitrogen oxides is not performed or the catalyst is regenerated or preheated, the catalyst module 400 is pivoted and moved to the second position.

Therefore, according to the first embodiment of the present invention, there is no need to separately form a bypass flow path for bypassing the selective catalytic reduction reactor 102.

In addition, according to the second embodiment of the present invention, the selective catalytic reduction reactor 102 can easily regenerate or preheat the catalyst after the catalyst module 400 is pivotally moved in the second position within the reactor body 300 have.

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.

101, 102: selective catalytic reduction reactor
300: reactor body
301: inlet
309: Outlet
400: catalyst module
430: pivot shaft
450: Stopper
500:
510: pull wire
550: drive motor
610:
701, 702: Heating device
760: Recirculation flow path
780: Reducing agent supply flow
800: soot blower
850: compressed air supply
900: decomposition chamber
950: Blower

Claims (11)

A reactor body connected to an exhaust flow path through which exhaust gas flows;
A catalyst module rotatable within the reactor body around a pivot shaft provided on an inner wall of the reactor body; And
And a swing drive unit
(SCR) < / RTI > The method according to claim 1,
At least one or more pivot shafts are provided on opposite side inner walls of the reactor body,
Wherein at least a pair of the catalyst modules are connected to the pivot shaft, respectively. The method according to claim 1,
The swing drive unit includes:
A tow wire connected to the other side opposite to one side of the catalyst module connected to the pivot;
A driving motor provided on the outside of the reactor main body to wind the pulling wire,
And a second catalytic reduction reactor. 4. The method according to any one of claims 1 to 3,
Wherein the catalyst module has a first position having a length in a direction intersecting the moving direction of the exhaust gas and a second position having a length in a direction in parallel with the moving direction of the exhaust gas in close contact with the inner wall of the reactor body, Wherein the catalyst is a catalyst. 5. The method of claim 4,
Further comprising a stopper configured to allow the catalyst module to swing from the second position to the first position and stop at a predetermined position. 5. The method of claim 4,
Wherein the reactor body has a length in the longitudinal direction and the exhaust gas moves up and down,
Wherein the catalyst module moves from the first position to the second position by its own weight,
Wherein the catalyst module moves from the second position to the first position by the swivel driving unit. 5. The method of claim 4,
Further comprising a soot blower for injecting a high-pressure fluid into the catalyst module when the catalyst module is located at the second position. 5. The method of claim 4,
Further comprising a heating device for heating the catalyst module when the catalyst module is in the second position. 9. The method of claim 8,
Wherein the heating device is an electric heater. 9. The method of claim 8,
The heating device includes:
A recirculation flow path for moving the exhaust gas branched from the exhaust passage behind the reactor body toward the catalyst module located at the second position;
A burner installed on the recirculation flow path
And a second catalytic reduction reactor. 11. The method of claim 10,
And a circulation blower provided on the recirculation flow path.

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