KR20190114171A - Reactor for selective catalytic reduction - Google Patents

Abstract

The present invention relates to a selective catalytic reduction reactor. According to an embodiment of the present invention, the selective catalytic reduction reactor comprises: a reactor body embedded with a catalyst for reducing nitrogen oxides; a distribution pipe installed inside one side of the reactor body; a plurality of injection pipes each having a plurality of injection holes for injecting compressed air toward the catalyst and having one end connected to the distribution pipe; a compressed air supply pipe penetrating the reactor body and connected to the distribution pipe; and an injection control valve installed on the compressed air supply pipe.

Description

Selective Catalytic Reduction Reactor {REACTOR FOR SELECTIVE CATALYTIC REDUCTION}

The present invention relates to a selective catalytic reduction reactor, and more particularly to a selective catalytic reduction reactor used to reduce the nitrogen oxide (NOx) contained in the exhaust gas.

As industrialization progressed rapidly, the use of various 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 oxide contained in the exhaust gas is reacted with the reducing agent while the catalyst is passed through the exhaust gas and the reducing agent together to reduce the 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.

On the other hand, due to the limited space of the vessel, the simplification is required for the selective catalytic reduction system used in the vessel.

In addition, the catalyst disposed inside the reactor to promote the reduction reaction, the activity of the catalyst is continuously reduced as the foreign matter gets stuck during the operation time. Thus, by using a soot blower (soot blower) to inject a high-pressure fluid toward the catalyst to remove foreign substances trapped in the catalyst to maintain the activity of the catalyst.

In the related art, as shown in FIG. 1, one side of the plurality of injection pipes 42 is inserted into the reactor 30 to inject compressed air toward the catalyst 35 in the reactor 30. The plurality of injection pipes 42 are formed with a plurality of injection holes 49 for injecting compressed air, respectively.

On the other side of the plurality of injection pipes 42 outside the reactor 30, control valves 47 are installed to control the compressed air supplied to the plurality of injection pipes 42, respectively.

In addition, the other side of the plurality of injection pipes 42 outside the reactor 30 is connected to the main pipe 41 to receive the compressed air. The main pipe 41 is connected to the compressed air supply pipe 48.

Through such a configuration, when the exhaust gas discharged from the engine flows into the reactor 30 during the operation of the selective catalytic reduction system, and after a predetermined time or the actual nitrogen oxide reduction rate of the selective catalytic reduction system does not reach the target nitrogen oxide reduction rate. As the control valve 47 opens, compressed air is injected toward the catalyst 35 through the injection holes 49 of the plurality of injection pipes 42. The compressed air sprayed in this way physically removed foreign matters attached to the catalyst 35.

However, in the conventional soot blower structure as described above, since the control valve 47 must be installed for each of the plurality of injection pipes 42, not only the initial installation cost is increased but also a lot of time and cost for maintenance. Was exhausted.

In addition, since the plurality of injection pipes 42 are connected to one main pipe 41 outside the reactor 30, there is a problem that the space required for installing and maintaining them is increased.

Embodiments of the present invention provide a selective catalytic reduction reactor that improves space utilization and minimizes the components used to improve ease of installation and maintenance.

According to an embodiment of the present invention, the selective catalytic reduction reactor includes a reactor body in which a catalyst for reducing nitrogen oxides (NOx) is incorporated, a distribution pipe installed inside one side of the reactor body, and compressed air is injected toward the catalyst. A plurality of injection pipes each having a plurality of injection holes for connecting to the distribution pipe, a compressed air supply pipe connected to the distribution pipe through the reactor body, and an injection control valve installed on the compressed air supply pipe. do.

The selective catalytic reduction reactor may include a first support part installed inside one side of the reactor body to support the distribution pipe, and a second support part installed inside the other side of the reactor body to support the other ends of the plurality of injection pipes. It may further include.

In addition, one or more additional injection holes may be formed in the distribution pipe for injecting compressed air toward the catalyst.

In addition, the distribution pipe may include a shape that gradually increases in diameter or cross-sectional area as it moves away from the point connected with the compressed air supply pipe.

The plurality of injection pipes may be arranged at equal intervals.

The distribution pipe, the plurality of injection pipes, and the compressed air supply pipe may be coupled to each other using a flange.

In the selective catalytic reduction reactor described above, the cross section of the reactor body may be formed in a square.

And the distribution pipe may be formed in a straight shape along one side of the cross section of the reactor body.

The plurality of injection pipes may extend in a direction crossing the longitudinal direction of the distribution pipe.

In the selective catalytic reduction reactor described above, the cross section of the reactor body may be formed in a circular or elliptical shape.

And the distribution pipe may be formed in a curved shape along the shape of the inner surface of the reactor body.

The plurality of injection pipes may extend in the transverse direction of the reactor body.

According to the embodiment of the present invention, the selective catalytic reduction reactor can improve space utilization and minimize the parts used to improve the ease of installation and maintenance.

1 is a cross-sectional view showing a conventional selective catalytic reduction reactor.
2 is a block diagram showing a selective catalytic reduction system using a selective catalytic reduction reactor according to a first embodiment of the present invention.
3 is a cross-sectional view illustrating the selective catalytic reduction reactor of FIG. 2.
4 is a cross-sectional view showing a selective catalytic reduction reactor according to a second embodiment of the present invention.
5 is a cross-sectional view showing a selective catalytic reduction reactor according to a third 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 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.

In addition, in various embodiments, components having the same configuration will be representatively described in the first embodiment using the same reference numerals, and in other embodiments, only the configuration different from the first embodiment will be described. do.

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, but includes, for example, modification of the form 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. 2 and 3.

The selective catalytic reduction reactor 101 according to the first embodiment of the present invention is used in a selective catalytic reduction (SCR) system for reducing nitrogen oxides (NOx) contained in exhaust gas discharged from a power unit. . In one example, the power unit may be a diesel engine used as the main power source for supplying propulsion to the vessel. The diesel engine may also be a two-stroke low speed diesel engine for ships.

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

As shown in FIG. 2, the exhaust gas containing the nitrogen oxide (NOx) discharged from the power unit moves through the exhaust flow path 610. That is, the exhaust flow path 610 may be connected to the exhaust port of the diesel engine as a power unit to exhaust the exhaust gas of the diesel engine and may be connected to the selective catalytic reduction reactor 101.

In addition, a reducing agent injector 710 for injecting a reducing agent into the exhaust channel 610 or the inlet of the selective catalytic reduction reactor 101 in front of the selective catalytic reduction reactor 101 may be installed. 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 reducing agent injector 710 receives the reducing agent from the reducing agent supply unit 780 and injects the reducing agent. For example, the reducing agent injector 710 may inject a urea (urea, CO (NH ₂ ) ₂ ) aqueous solution. Although ammonia (NH ₃ ) is used as a reducing agent which directly reacts with nitrogen oxide in the catalyst 350 to be described later, it is common to use a stable aqueous solution of urea because ammonia itself is not easy to store and transport as a contaminant. That is, the aqueous urea solution corresponds to the reducing agent precursor. The injected urea in the reducing agent injection assembly (710) (urea, CO ( NH 2) 2) aqueous solution is decomposed, while moving along the discharge path 610 generate ammonia (NH ₃₎ and isocyanate (Isocyanic acid, HNCO) do. Isocyanic acid (HNCO) is further decomposed into ammonia (NH ₃ ) and carbon dioxide (CO ₂ ). That is, urea is decomposed to produce ammonia, which is a reducing agent that reacts with nitrogen oxides. In addition, although not shown, a decomposition chamber or a vaporizer may be installed on the exhaust flow path 610 to effectively decompose urea.

In addition, the reducing agent injector 710 may spray an aqueous ammonia solution. When the reducing agent injector 710 injects the aqueous ammonia solution, the injected ammonia aqueous solution may be vaporized while moving along the exhaust flow path 610.

The reducing agent supply unit 780 supplies a reducing agent to be injected by the reducing agent injection unit 710. For example, when the emission of the exhaust gas discharged from the engine is changed according to the load change of the engine, the amount of the reducing agent required to reduce the nitrogen oxide contained in the exhaust gas is also changed. Thus, the reducing agent supply unit 780 may adjust the supply amount of the reducing agent so that the appropriate amount of reducing agent can be supplied according to the operating conditions of the engine or the exhaust gas discharge situation. Specifically, the reducing agent supply unit 780 is a reducing agent storage tank for storing the reducing agent to be supplied to the reducing agent injection unit 710, 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.

2 and 3, the selective catalytic reduction (SCR) reactor 101 according to the first embodiment of the present invention comprises a reactor body 300, a distribution pipe 411, a plurality of injections Pipe 420, compressed air supply pipe 480, and control valve 470.

In addition, the selective catalytic reduction reactor 101 according to the first embodiment of the present invention may further include a first support 510 and a second support 520.

The reactor body 300 is connected to the exhaust passage 610, respectively, and has an inlet for exhaust gas and an outlet for exhaust gas. In the first embodiment of the present invention, the cross section of the reactor body 300 may be formed in a square.

A catalyst 350 for reducing nitrogen oxides (NOx) is installed in the reactor body 300. 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. The catalyst 350 may be installed in a module form, and a plurality of catalyst modules are loaded in a direction crossing the direction in which the exhaust gas moves in the reactor body 300 to form a plurality of catalyst layers. The plurality of catalyst layers are spaced apart based on the direction in which the exhaust gas moves inside the reactor body 300.

In addition, the plurality of catalyst modules may be formed into a hexahedron. In one example, the plurality of catalyst modules may be cuboid or cube. As such, when the catalyst module is formed of a cube or a cube, it is easy to load the catalyst module, easy to replace and transport the catalyst module, and maximize the efficiency of the catalyst 350 included in the catalyst module.

In addition, the catalyst 350 may be made of various materials known to those skilled in the art, such as zeolite, vanadium, and platinum. 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. When 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 the nitrogen oxides contained in the exhaust gas at a relatively low temperature of more than 150 degrees Celsius and less than 250 degrees Celsius, sulfur oxides (SOx) of the exhaust gas and ammonia (NH ₃ ) as a reducing agent are generated. Is reacted to produce 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 350 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 poisoned catalyst 350 may be regenerated by raising the catalyst 350 installed inside the reactor body 300. .

The distribution pipe 410 is installed inside one side of the reactor body 300. In the first embodiment of the present invention, the distribution pipe 410 may be formed in a straight shape along one side of the cross section of the reactor body (300).

One end of the plurality of injection pipes 420 is connected to the distribution pipe 410. Each of the plurality of injection pipes 420 has a plurality of injection holes 429 for injecting compressed air toward the catalyst 350.

The compressed air injected from the injection hole 429 of the injection pipe 420 may regenerate the catalyst 350 by physically removing the foreign matter trapped in the catalyst 350 or by decomposing the catalyst poisoning material. However, in order to decompose the catalyst poisoning substance, the compressed air injected from the injection hole 429 of the injection pipe 420 should have a temperature higher than the decomposition temperature of the catalyst poisoning substance.

In addition, the plurality of injection pipes 420 may extend in a direction crossing the longitudinal direction of the distribution pipe 410, and the plurality of injection pipes 420 may be arranged at equal intervals.

The first support part 510 may be installed inside one side of the reactor body 300 to support the distribution pipe 410. The second support 520 may be installed inside the other side of the reactor body 300 to support the other ends of the plurality of injection pipes 420.

In addition, according to the first embodiment of the present invention, one or more additional injection holes 419 may be formed in the distribution pipe 410 to inject compressed air toward the catalyst 350.

The compressed air supply pipe 480 is connected to the distribution pipe 410 through the reactor body 300. Accordingly, the compressed air supply pipe 480 delivers the compressed air supplied from the outside of the reactor body 300 to the distribution pipe 410.

The compressed air supply unit 840 for supplying compressed air may be a separately provided compressed air tank or a pump for generating compressed air, and the supercharger mounted on the engine may supply the compressed air. That is, the compressed air can be supplied by various methods known to those skilled in the art.

The above-described distribution pipe 410, the plurality of injection pipes 420, and the compressed air supply pipe 480 may be coupled to each other using a flange.

The injection control valve 470 is installed on the compressed air supply pipe 480 to control whether compressed air is supplied. When the exhaust gas discharged from the engine flows into the reactor during the operation of the selective catalytic reduction system, and after a predetermined time or the actual nitrogen oxide reduction rate of the selective catalytic reduction system does not reach the target nitrogen oxide reduction rate, the injection control valve 470 opens. Compressed air is injected toward the catalyst 350 through the injection holes 429 of the plurality of injection pipes 420 and the injection holes 419 of the distribution pipe 410. In some cases, the injection control valve 470 may be opened even when the catalyst 350 is regenerated.

By such a configuration, the selective catalytic reduction reactor 101 according to the first embodiment of the present invention can increase the space utilization and minimize the parts used to improve the ease of installation and maintenance.

Specifically, since the compressed air distributed to the plurality of injection pipes 420 may be controlled through one injection control valve 470, the number of parts used may be reduced, and the initial installation cost and time required for maintenance may be reduced. Can be.

In addition, by distributing the distribution pipe 410 inside the reactor body 300, it is possible to minimize the space required for installation and maintenance.

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

As shown in FIG. 4, in the selective catalytic reduction reactor 102 according to the second embodiment of the present invention, the diameter or cross-sectional area is gradually increased as the distribution pipe 412 moves away from the point connected with the compressed air supply pipe 480. It includes increasing shapes. Accordingly, the flow rate of the compressed air injected from the injection holes 429 formed in the plurality of injection pipes 420 may be equalized.

If the diameter remains constant even if it is far from the point connected with the compressed air supply pipe 480, such as the distribution pipe 411 of the first embodiment, the injection pipe 420 connected relatively far from the point connected with the compressed air supply pipe 480 The compressed air injected from the injection hole 429 of the) may increase the flow rate.

However, in the second embodiment of the present invention, since the diameter or the cross-sectional area of the distribution pipe 412 gradually increases as the distance from the point connected with the compressed air supply pipe 480, the plurality of injection pipe 420 It is possible to equalize the flow rate of the compressed air injected from the injection hole (429).

Hereinafter, a selective catalytic reduction reactor 101 according to a third embodiment of the present invention will be described with reference to FIG. 5.

As shown in FIG. 5, in the selective catalytic reduction reactor 103 according to the third embodiment of the present invention, the cross section of the reactor body 300 may be formed in a circular or elliptical shape. In addition, the distribution pipe 413 may be formed in a curved shape along the shape of the inner surface of the reactor body 300.

In addition, the plurality of injection pipes 420 may extend in the transverse direction of the reactor body 300.

As such, even when the cross section of the reactor body 300 has various shapes such as circular or elliptical, the distribution pipe 413 may be effectively installed in the reactor body 300.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains 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 meaning and scope 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.

101, 102, 103: selective catalytic reduction reactor
300: reactor body
350: catalyst
411, 412, 413: distribution pipe
419: additional injection holes
420: injection pipe
429: injection hole
470: injection control valve
480: compressed air supply pipe
510: first support
520: second support portion
610: exhaust passage
710: reducing agent injection unit
780: reducing agent supply unit
840: compressed air supply

Claims (12)

A reactor body incorporating a catalyst for reducing nitrogen oxides (NOx);
A distribution pipe installed inside one side of the reactor body;
A plurality of injection pipes each having a plurality of injection holes for injecting compressed air toward the catalyst and having one end connected to the distribution pipe;
A compressed air supply pipe passing through the reactor body and connected to the distribution pipe; And
Injection control valve installed on the compressed air supply pipe
Selective catalytic reduction reactor comprising a. The method of claim 1,
A first support part installed inside one side of the reactor body to support the distribution pipe;
A second support part installed inside the other side of the reactor body to support the other ends of the plurality of injection pipes;
Selective catalytic reduction reactor further comprises. The method of claim 1,
Selective catalytic reduction reactor, characterized in that the distribution pipe is formed with one or more additional injection holes for injecting compressed air toward the catalyst. The method of claim 1,
And wherein said distribution pipe comprises a shape that gradually increases in diameter or cross-sectional area away from a point connected with said compressed air supply pipe. The method of claim 1,
Selective catalytic reduction reactor, characterized in that the plurality of injection pipes are arranged at equal intervals. The method of claim 1,
Wherein said distribution pipe, said plurality of injection pipes, and said compressed air supply pipe are interconnected using a flange. The method according to any one of claims 1 to 6,
Selective catalytic reduction reactor, characterized in that the cross section of the reactor body is formed in a square. The method of claim 7, wherein
The distribution pipe is a selective catalytic reduction reactor, characterized in that formed in a straight line along one side of the cross section of the reactor body. The method of claim 8,
And wherein the plurality of injection pipes extend in a direction crossing the longitudinal direction of the distribution pipe. The method according to any one of claims 1 to 6,
Selective catalytic reduction reactor, characterized in that the cross section of the reactor body is formed in a circular or elliptical. The method of claim 10,
The distribution pipe is a selective catalytic reduction reactor, characterized in that formed in a curved shape along the shape of the inner surface of the reactor body. The method of claim 11,
Selective catalytic reduction reactor, characterized in that the plurality of injection pipes extending in the transverse direction of the reactor body.

Images