KR20190114430A - Combined sncr and scr system - Google Patents

Abstract

A selective non-catalytic reduction and selective catalytic reduction composite system for reducing nitrogen oxides contained in exhaust gas discharged from a combustion chamber according to an embodiment of the present invention includes: an exhaust flow path for exhausting exhaust gas generated from a combustion chamber; a reactor installed on the exhaust flow path and having a built-in catalyst for reducing nitrogen oxide contained in the exhaust gas; a first injection unit provided on the exhaust flow path upstream of the reactor; a second injection unit installed in the combustion chamber; a rear branch flow path branched from the exhaust flow path downstream from the reactor; a decomposition chamber connected to the branch flow path; a reducing agent supply flow path connecting the decomposition chamber and the first injection unit; and a urea supply unit supplying urea to at least one of the decomposition chamber and the second injection unit.

Description

Selective Catalytic Reduction and Selective Catalytic Reduction Complex Systems

The present invention relates to selective catalytic free reduction and selective catalytic reduction systems, and more particularly to selective catalytic free reduction and selective catalytic reduction systems used to reduce NOx contained in exhaust gases.

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. Among these, representative facilities for reducing nitrogen oxides include a selective non-catalytic reduction (SNCR) system and a selective catalytic reduction (SCR) system.

Selective non-catalytic reduction (SNCR0 system is a method of reducing nitrogen oxides (NOx) by reacting with nitrogen oxides (NOx) by directly injecting a solution of urea or ammonia, which is a reducing agent, into an exhaust gas having a high temperature generated in a combustion chamber. In this case, the exhaust gas generated in the combustion chamber may have a temperature in the range of 800 degrees Celsius to 1100 degrees Celsius.

The selective catalytic reduction (SCR) system is a method of reducing nitrogen oxides (NOx) by reacting a reducing agent with nitrogen oxides (NOx) in a reactor equipped with a catalyst. In the selective catalytic reduction system, a urea aqueous solution or ammonia aqueous solution, which is a reducing agent, is injected into an exhaust gas having a relatively low temperature, or a urea aqueous solution is decomposed into ammonia gas in a separate decomposition chamber or vaporizer and then injected into the exhaust gas. . The reducing agent injected in this way flows into the reactor in which the catalyst is installed together with the exhaust gas. And the temperature of the exhaust gas flowing into the reactor may have a temperature in the range of 200 degrees Celsius to 500 degrees Celsius.

Selective non-catalytic reduction systems have been used more frequently than selective catalytic reduction systems in terms of installation costs and maintenance in terms of NOx reduction rates of 40% to 60%. The use of selective catalytic reduction systems with NOx reductions of up to 95% or more has been greatly increased, and complex systems in which both selective non-catalytic reduction systems and selective catalytic reduction systems are used together are also widely used.

In the conventional combined system using a selective non-catalytic reduction system and a selective catalytic reduction system, the urea aqueous solution is directly injected into the exhaust gas for selective non-catalytic reduction, and the urea aqueous solution is decomposed into ammonia gas in a separate decomposition chamber or vaporizer. It was then injected into the exhaust gas and used for selective catalytic reduction.

However, in order to operate the decomposition chamber or vaporizer separately, a heating device such as an electric heater, steam, or burner for supplying thermal energy to the decomposition chamber or vaporizer is required, and there is an additional cost for operating the heating device. In addition, it takes time to decompose urea, as well as storing and supplying the decomposed ammonia gas.

In addition, when the temperature of the exhaust gas discharged from the combustion chamber is varied according to the type of the combustion chamber or the surrounding environment, a situation in which an optional non-catalytic reduction system and a selective catalytic reduction system are used together may occur.

Specifically, in a situation where the temperature of the exhaust gas discharged from the combustion chamber does not reach a temperature suitable for the selective non-catalytic reduction reaction, the urea aqueous solution directly injected into the exhaust gas for the selective non-catalytic reduction may not smoothly reduce the nitrogen oxides. have.

In addition, even when the temperature of the exhaust gas discharged from the combustion chamber is a temperature suitable for decomposing urea to ammonia in the decomposition chamber or vaporizer, the heating device is unnecessarily operated to supply thermal energy to the decomposition chamber or vaporizer, resulting in waste of energy. Can be.

In addition, when the temperature of the exhaust gas discharged from the combustion chamber is higher than a temperature suitable for decomposing urea to ammonia in the decomposition chamber or the vaporizer, the decomposition efficiency of the urea may be lowered, thereby lowering the overall efficiency of the system.

As such, when the temperature of the exhaust gas passing through the position where the reducing agent is injected is changed due to various factors, the reducing agent injected into the exhaust gas may not be completely decomposed according to the situation, so that the efficiency of reducing nitrogen oxides is reduced or deposits are reduced. There is a problem that energy is generated or wasted unnecessarily.

In addition, in the conventional composite system in which the selective non-catalytic reduction system and the selective catalytic reduction system are applied together, a reducing agent supplying device for supplying a reducing agent for the selective non-catalytic reduction system and a reducing agent supply for supplying the reducing agent for the selective catalytic reduction system The device was separated and operated independently. Thus, since the overall system configuration becomes complicated, installation and maintenance are cumbersome and space is wasted.

Embodiments of the present invention provide a selective non-catalytic reduction and selective catalytic reduction complex system that can efficiently supply a reducing agent.

According to an embodiment of the present invention, the selective non-catalytic reduction and selective catalytic reduction complex system for reducing nitrogen oxides contained in the exhaust gas discharged from the combustion chamber includes an exhaust flow path for exhausting the exhaust gas generated in the combustion chamber, and the exhaust gas. A reactor provided on the flow path and having a built-in catalyst for reducing nitrogen oxide contained in the exhaust gas, a first injection part provided on the exhaust flow path upstream of the reactor, a second injection part provided in the combustion chamber, A rear branch flow passage branched from the exhaust flow passage downstream from the reactor, a decomposition chamber connected to the branch flow passage, a reducing agent supply flow path connecting the decomposition chamber and the first injector, and the decomposition chamber and the second portion A urea supply for supplying urea to at least one of the four dead quarters.

The selective non-catalyst reduction and selective catalytic reduction complex system is installed on the rear branch flow path and controls a temperature of the exhaust gas moving along the rear branch flow path, and is installed on the rear branch flow path to exhaust the exhaust gas. It may further include a blower for moving a portion of the exhaust gas moving along the flow path to the rear branch flow path.

In addition, the selective non-catalytic reduction and selective catalytic reduction composite system includes an oxygen concentration sensor installed on the rear branch flow path, a combustion fuel supply unit supplying fuel to the heating device, and supplying combustion air to the heating device. It may further include a combustion air supply.

In addition, the selective non-catalytic reduction and selective catalytic reduction complex system is installed on the exhaust flow path between the combustion chamber and the reactor economizer (economizer) for recovering thermal energy from the exhaust gas moving along the exhaust flow path, and the The urea supply unit may further include a urea storage unit for storing urea to be supplied.

The selective non-catalytic reduction and selective catalytic reduction complex system may further comprise an additional reducing agent supply flow path connecting the decomposition chamber and the second injection. The urea supply unit may supply urea only to the decomposition chamber.

In addition, the selective non-catalyst reduction and selective catalytic reduction composite system includes a third injection unit provided on the exhaust passage upstream of the first injection unit, a fourth injection unit installed in the combustion chamber, and the decomposition chamber and the It may further comprise an additional reducing agent supply flow passage connecting the second injection. The urea supply unit may supply urea to the decomposition chamber, the third injection unit, and the fourth injection unit.

In addition, according to another embodiment of the present invention, the selective non-catalytic reduction and selective catalytic reduction complex system for reducing the nitrogen oxide contained in the exhaust gas discharged from the combustion chamber and the exhaust flow path for exhausting the exhaust gas generated in the combustion chamber; And a reactor provided on the exhaust passage and having a catalyst embedded therein for reducing nitrogen oxide contained in the exhaust gas, a first injection unit provided on the exhaust passage upstream of the reactor, and a second installed in the combustion chamber. An injection section, a forward branch flow passage branched from the exhaust flow passage upstream of the reactor, a decomposition chamber connected to the branch flow passage, a reducing agent supply flow path connecting the decomposition chamber and the first injection portion, and the decomposition chamber and the A urea supply for supplying urea to at least one of the second injections.

The selective non-catalyst reduction and selective catalytic reduction complex system is installed on the front branch flow path and controls a temperature of the exhaust gas moving along the front branch flow path, and is installed on the front branch flow path to exhaust the exhaust gas. It may further include a blower for moving a portion of the exhaust gas moving along the flow path to the front branch flow path.

In addition, the selective non-catalyst reduction and selective catalytic reduction complex system may further include a temperature control external air supply unit for supplying the outside air to the front branch flow path to adjust the temperature of the exhaust gas moving along the front branch flow path.

In addition, the selective non-catalyst reduction and selective catalytic reduction composite system includes an oxygen concentration sensor installed on the front branch flow path, a combustion fuel supply unit supplying fuel to the heating device, and supplying combustion air to the heating device. It may further include a combustion air supply.

In addition, the selective non-catalytic reduction and selective catalytic reduction complex system is installed on the exhaust flow path between the combustion chamber and the reactor economizer (economizer) for recovering thermal energy from the exhaust gas moving along the exhaust flow path, and the The urea supply unit may further include a urea storage unit for storing urea to be supplied.

The selective non-catalytic reduction and selective catalytic reduction complex system may further comprise an additional reducing agent supply flow path connecting the decomposition chamber and the second injection. The urea supply unit may supply urea only to the decomposition chamber.

In addition, the selective non-catalyst reduction and selective catalytic reduction composite system includes a third injection unit provided on the exhaust passage upstream of the first injection unit, a fourth injection unit installed in the combustion chamber, and the decomposition chamber and the It may further comprise an additional reducing agent supply flow passage connecting the second injection. The urea supply unit may supply urea to the decomposition chamber, the third injection unit, and the fourth injection unit.

According to an embodiment of the present invention, the selective non-catalytic reduction and selective catalytic reduction complex system can supply the reducing agent efficiently.

1 is a block diagram of a selective non-catalytic reduction and selective catalytic reduction complex system according to a first embodiment of the present invention.
2 is a block diagram of a selective non-catalytic reduction and selective catalytic reduction complex system according to a second embodiment of the present invention.
3 is a block diagram of a selective non-catalytic reduction and selective catalytic reduction complex system according to a third embodiment of the present invention.
4 is a block diagram of a selective non-catalytic reduction and selective catalytic reduction complex system according to a fourth embodiment of the present invention.
5 is a block diagram of a selective non-catalytic reduction and selective catalytic reduction complex system according to a fifth embodiment of the present invention.
6 is a block diagram of a selective non-catalytic reduction and selective catalytic reduction complex system according to a sixth embodiment of the present invention.
7 is a block diagram of a heating apparatus that can be used in the selective catalytic free reduction and selective catalytic reduction complex systems according to the first to sixth embodiments 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, a selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) complex system 101 according to a first embodiment of the present invention will be described with reference to FIG. 1.

The selective non-catalytic reduction and selective catalytic reduction complex system 101 according to the first embodiment of the present invention reduces the nitrogen oxides (NOx) contained in the exhaust gas discharged from the combustion chamber 100. Here, the combustion chamber 100 may be an engine used in a ship or a vehicle, or an internal combustion engine or a furnace used in a plant. For example, the exhaust gas discharged from the combustion chamber 100 may have a temperature within a range of 200 degrees Celsius to 1100 degrees Celsius.

As shown in FIG. 1, the selective non-catalytic reduction and selective catalytic reduction complex system 101 according to the first embodiment of the present invention includes an exhaust passage 610, a reactor 300, a first injection unit 510, The second injection part 520, the rear branch flow path 680, the decomposition chamber 500, the reducing agent supply flow path 651, and the urea supply part 810 are included.

In addition, the selective non-catalytic reduction and selective catalytic reduction complex system 101 according to the first embodiment of the present invention includes a heating device 400, a blower 450, an economizer 900, and a urea storage unit 880. It may further include.

The exhaust passage 610 moves the exhaust gas containing the nitrogen oxides (NOx) discharged from the combustion chamber 100. And the exhaust passage 610 is connected to the reactor 300 to be described later.

The reactor 300 is installed on the exhaust passage 610. That is, the reactor 300 receives the exhaust gas discharged from the combustion chamber 100 through the exhaust flow path 610. In addition, the reactor 300 includes a catalyst 350 for reducing nitrogen oxide (NOx) contained in 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 the first embodiment of the present invention, the catalyst 350 installed in the reactor 300 may be installed in a modular form. A plurality of catalyst modules may be loaded in a direction crossing the direction in which the exhaust gas moves in the reactor 300 to form a plurality of catalyst layers. The plurality of catalyst layers may be spaced apart based on the direction in which the exhaust gas moves in the reactor 300.

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 250 degrees Celsius to 350 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 catalyst 350 in the reactor 300 may be heated to regenerate the poisoned catalyst 350.

The first injector 510 is installed on the exhaust passage 610 upstream of the reactor 300. In addition, the second injection unit 520 is installed in the combustion chamber 100. In the first embodiment of the present invention, the first injector 510 injects ammonia (NH ₃ ) gas generated in the decomposition chamber 500 to be described later, the second injector 520 is a urea supply unit (to be described later) 810 can be injected directly from the aqueous urea solution.

The rear branch passage 680 is branched from the exhaust passage 610 downstream of the reactor 300 and connected to the decomposition chamber 500, which will be described later.

The decomposition chamber 500 receives a part of the exhaust gas which has passed through the reactor 300 through the rear branch flow path 680. In addition, the decomposition chamber 500 receives urea (urea, CO (NH ₂ ) ₂ ) from the urea supply unit 810 which will be described later. The urea storage unit 880 stores urea to be supplied by the urea supply unit 810. In this case, the urea storage unit 880 may store the urea in the form of an aqueous solution, and the urea supply unit 810 may supply the aqueous urea solution. The reducing agent that reacts directly with nitrogen oxides (NOx) is ammonia (NH ₃ ), but since ammonia itself is not easy to store and transport as a pollutant, a stable aqueous solution of urea is stored in the urea storage unit 880 and then decomposed to ammonia. Generate gas. That is, urea corresponds to a reducing agent precursor. Specifically, the urea solution supplied by the urea supply unit 810 to the decomposition chamber 500 is decomposed to generate ammonia (NH ₃ ) and isocyanic acid (HNCO). 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.

The reducing agent supply passage 651 connects the decomposition chamber 500 and the first injector 510. Therefore, the ammonia gas generated in the decomposition chamber 500 may be delivered to the first injector 510 through the reducing agent supply passage 651 to be injected.

As described above, ammonia gas, which is a reducing agent injected through the first injection unit 510, is used for the selective catalytic reduction reaction.

The blower 450 is installed on the rear branch flow path 680 to move a portion of the exhaust gas moving along the exhaust flow path 610 to the rear branch flow path 680. That is, a part of the exhaust gas moving along the exhaust flow path 610 by the blower 450 is directed to the decomposition chamber 500. In addition, the blower 450 may adjust the flow rate of the exhaust gas moving along the rear branch flow path 680.

The heating device 400 is installed on the rear branch flow path 680 to adjust the temperature of the exhaust gas moving along the rear branch flow path 680. In the first embodiment of the present invention, the reactor 300 is maintained above the active temperature of the catalyst 350 for the selective catalytic reduction reaction. That is, the interior of the reactor 300 may be maintained at or above a temperature in the range of 250 degrees Celsius to 350 degrees Celsius. Thus, the exhaust gas that has passed through the reactor 300 has significant thermal energy.

In the first embodiment of the present invention, by supplying a part of the exhaust gas passed through the reactor 300 to the decomposition chamber 500, the thermal energy of the exhaust gas can be utilized for decomposition of urea. Therefore, when the temperature of the exhaust gas supplied to the decomposition chamber 500 through the rear branch flow path 680 is within the decomposition temperature range of the urea, it is not necessary to operate the heating device 400. At this time, the decomposition temperature range of the urea may be in the range of 250 degrees Celsius to 600 degrees Celsius.

That is, according to the first embodiment of the present invention, the heating device 400 is used in accordance with the temperature of the exhaust gas supplied to the decomposition chamber 500 through the rear branch flow path 680 to be of the decomposition chamber 500 To control the temperature.

Specifically, in the first embodiment of the present invention, the heating device 400 is not operated if the temperature of the exhaust gas supplied to the decomposition chamber 500 through the rear branch flow passage 680 is within the decomposition temperature range of the urea. . On the contrary, if the temperature of the urea does not reach the decomposable temperature range, the heating device 400 raises the exhaust gas traveling along the rear branch flow path 680 to the decomposable temperature range of the urea.

As such, according to the first embodiment of the present invention, since the heating device 400 is not always operated and is used auxiliary depending on the temperature of the exhaust gas supplied to the decomposition chamber 500 through the rear branch flow path 680. , The operation rate of the heating device 400 can be minimized. That is, the consumption of fuel or other energy due to the use of the heating device 400 can be reduced.

In addition, minimizing the operation rate of the heating device 400 means that the time required for the heating device 400 to be operated to increase the temperature of the decomposition chamber to the decomposition temperature of the urea can be reduced. As a result, it is possible to reduce the overall time taken to produce ammonia by decomposing urea in the decomposition chamber 500. That is, the residence time required for the conversion of urea to ammonia can be reduced, thereby reducing the size of the decomposition chamber 500 or the length of the reducing agent supply passage 651.

In addition, the urea supply unit 810 supplies the urea solution to the second injection unit 520 together with the decomposition chamber 500. That is, the second injection unit 520 injects the urea aqueous solution directly supplied from the urea supply unit 810 to the combustion chamber 520.

As described above, the urea injected from the second injection unit 520 is decomposed into ammonia by a relatively high temperature inside the combustion chamber 100 and reacts with nitrogen oxide. That is, the urea injected from the second injection unit 520 is used for the selective non-catalytic reduction reaction.

An economizer 900 is installed on the exhaust passage 610 between the combustion chamber 100 and the reactor 300. The economizer 900 recovers and recycles thermal energy from exhaust gas moving along the exhaust passage 610. Therefore, the exhaust gas is lowered in temperature while passing through the economizer 900. That is, even if the temperature of the exhaust gas discharged from the combustion chamber 100 is 800 degrees Celsius or more, the temperature of the exhaust gas reaching the reactor 300 through the economizer 900 may be 500 degrees Celsius or less.

With such a configuration, according to the first embodiment of the present invention, the selective non-catalytic reduction and selective catalytic reduction complex system 101 can efficiently supply a reducing agent.

Specifically, the energy and time consumed to decompose urea into ammonia in the decomposition chamber 500 may be minimized by using the thermal energy of the exhaust gas passed through the reactor 300.

In addition, one urea supply unit 810 may be used to simultaneously supply a reducing agent to be used for the selective catalytic reduction reaction and a reducing agent to be used for the selective catalytic reduction reaction. Through this, it is possible to integrally manage the total amount of reducing agent required for the selective catalytic reduction and selective catalytic reduction complex system 101.

In addition, the overall configuration of the selective catalytic reduction and selective catalytic reduction complex system 101 may be simplified to increase the ease of installation and maintenance and to improve space utilization.

In addition, since the form of the reducing agent is appropriately converted according to the temperature of the exhaust gas, it is possible to prevent a phenomenon in which urea is not completely converted into ammonia and generates a deposit in the system.

Hereinafter, a selective non-catalytic reduction and selective catalytic reduction system 102 according to a second embodiment of the present invention will be described with reference to FIG. 2.

As shown in FIG. 2, the selective non-catalytic reduction and selective catalytic reduction system 102 according to the second embodiment of the present invention further comprises an additional reducing agent connecting the decomposition chamber 500 and the second injector 520. It further includes a supply flow path 652. The urea supply unit 810 supplies urea only to the decomposition chamber 500. That is, unlike the first embodiment, in the second embodiment of the present invention, the ammonia generated in the decomposition chamber 500 without the injection of the urea aqueous solution is directly supplied from the urea supply unit 810 in the second injection unit 520 It will inject gas.

By such a configuration, the selective non-catalytic reduction and selective catalytic reduction complex system 102 according to the second embodiment of the present invention can stably supply a reducing agent.

Specifically, even when the temperature of the exhaust gas generated in the combustion chamber 100 varies depending on the type of the combustion chamber 100 or the surrounding environment, the ammonia generated in the decomposition chamber 500 may be inadequate to directly decompose urea into ammonia. By using the gas in the selective non-catalytic reduction reaction, it is possible to stably supply a reducing agent for the selective non-catalytic reduction reaction.

Hereinafter, the selective non-catalytic reduction and selective catalytic reduction system 103 according to the third embodiment of the present invention will be described with reference to FIG. 3.

As shown in FIG. 3, the selective non-catalytic reduction and selective catalytic reduction system 103 according to the third embodiment of the present invention is installed on the exhaust passage 610 upstream of the first injector 510. It further includes an injection unit 530, a fourth injection unit 540 installed in the combustion chamber 100, and an additional reducing agent supply flow path 652 connecting the decomposition chamber 500 and the second injection unit 520. .

In addition, in the third embodiment of the present invention, the urea supply unit 810 supplies urea to the decomposition chamber 500, the third injection unit 530, and the fourth injection unit 540. That is, unlike the first embodiment, in the third embodiment of the present invention, the ammonia generated in the decomposition chamber 500 without the injection of the urea aqueous solution is directly supplied from the urea supply unit 810 in the second injection unit 520 It will inject gas.

 In addition, according to the third embodiment of the present invention, the first injector 510 and the third injector 530 inject a reducing agent to be used for the selective catalytic reduction reaction, and the second injector 520 and the fourth injector. The sand 540 sprays a reducing agent to be used for the selective non-catalytic reduction reaction. The first injector 510 and the third injector 530, and the second injector 520 and the fourth injector 540 may be selectively used.

Specifically, when the temperature of the exhaust gas generated in the combustion chamber 100 varies depending on the type of the combustion chamber 100 or the surrounding environment, and is suitable to decompose urea into ammonia, the urea aqueous solution through the fourth injection unit 540. And spray it, it can be used as a reducing agent for the selective catalytic reduction reaction.

On the contrary, if the temperature of the exhaust gas generated in the combustion chamber 100 is unsuitable to directly decompose urea into ammonia, the ammonia gas generated in the decomposition chamber 500 is injected through the second injector 520. This may be used as a reducing agent for the selective non-catalytic reduction reaction.

As such, by selectively using the second injector 520 and the fourth injector 540 according to the temperature of the exhaust gas generated in the combustion chamber 100, a stable and selective supply is provided by supplying a reducing agent suitable for the current exhaust gas temperature. It is possible to carry out a catalytic reduction reaction.

In addition, when the temperature of the exhaust gas flowing into the reactor 300 fluctuates and is suitable to directly decompose urea into ammonia, the third injection unit 530 may be used in the exhaust flow path 610 upstream of the reactor 300. The sprayed aqueous urea solution can be used as a reducing agent for the selective catalytic reduction reaction. In this case, since it is not necessary to operate the heating device 400 and the blower 450, it is possible to reduce the energy consumed unnecessarily for the operation of the system.

On the contrary, when the temperature of the exhaust gas flowing into the reactor 300 fluctuates and is inappropriate to decompose urea into ammonia, the ammonia gas generated in the decomposition chamber 500 is injected through the first injector 510. And it can be used as a reducing agent for the selective catalytic reduction reaction.

As such, by selectively using the first injector 510 and the third injector 530 according to the temperature of the exhaust gas introduced into the reactor 300, a stable selective is provided by supplying a reducing agent suitable for the current exhaust gas temperature. In addition to performing the catalytic reduction reaction, the operation of the heating device 400 and the blower 450 may be minimized to reduce energy and time consumption due to the operation of the heating device 400 and the blower 450.

By such a configuration, the selective non-catalytic reduction and selective catalytic reduction complex system 103 according to the third embodiment of the present invention can supply the reducing agent more efficiently and stably.

Hereinafter, the selective non-catalytic reduction and selective catalytic reduction system 104 according to the fourth embodiment of the present invention will be described with reference to FIG. 4.

As shown in FIG. 4, the selective non-catalytic reduction and selective catalytic reduction system 104 according to the fourth embodiment of the present invention further includes a forward branch flow path 640. The forward branch passage 640 branches in the exhaust passage 610 upstream of the reactor 300. Incidentally, the rear branch flow path 680 used in the first embodiment is omitted in the fourth embodiment. The other configuration is the same as in the first embodiment.

In addition, the forward branch passage 640 may branch from the exhaust passage 610 upstream than the economizer 900.

In addition, in the fourth embodiment of the present invention, the decomposition chamber 500 is connected to the front branch flow path 640, the heating device 400 and the blower 450 is installed on the front branch flow path (640). Accordingly, the heating device 400 adjusts the temperature of the exhaust gas moving along the forward branch flow path 640, and the blower 450 passes a portion of the exhaust gas moving along the exhaust flow path 610 to the front branch flow path 640. Move to). That is, the heating device 400 is used in accordance with the temperature of the exhaust gas supplied to the decomposition chamber 500 through the front branch flow path 640 to adjust the temperature of the decomposition chamber 500, the blower 450 is The flow rate of the exhaust gas moving along the front branch flow path 640 may be adjusted.

Specifically, in the fourth embodiment of the present invention, the heating device 400 is not operated if the temperature of the exhaust gas supplied to the decomposition chamber 500 through the front branch flow passage 640 is within the decomposition temperature range of the urea. . On the contrary, if the temperature of the exhaust gas does not reach the decomposable temperature range of the urea, the heating device 400 raises the exhaust gas moving along the front branch flow path 640 to the decomposable temperature range of the urea.

However, in the fourth embodiment of the present invention, by supplying the exhaust gas branched from the exhaust flow path 610 upstream than the reactor 300 to the decomposition chamber 500, having a relatively higher temperature than the first embodiment The exhaust gases can be used for the decomposition of urea. In addition, when the temperature of the exhaust gas supplied to the decomposition chamber 500 through the front branch flow path 640 is within the decomposable temperature range of the urea, the heating device 400 does not need to be operated, and thus the operation rate of the heating device can be significantly lowered. have.

In addition, the selective non-catalytic reduction and selective catalytic reduction system 104 according to the fourth embodiment of the present invention supplies the outside air to the front branch flow path 640 to adjust the temperature of the exhaust gas moving along the front branch flow path 640. It may further include a temperature control external air supply unit 460 to adjust.

The temperature of the exhaust gas supplied to the decomposition chamber 500 along the front branch flow path 640 may be higher than the decomposition temperature range of the urea. For example, the decomposable temperature range of urea is 250 degrees Celsius to 600 degrees Celsius. If the temperature of the exhaust gas supplied to the decomposition chamber 500 through the front branch flow path 640 is 800 degrees Celsius or more, the decomposition chamber ( Urea may not be degraded smoothly.

At this time, the temperature control outside air supply unit 460 supplies the outside air to the front branch flow path 640 and the temperature of the exhaust gas supplied to the decomposition chamber 500 through the front branch flow path 640 ranges from 250 degrees Celsius to 600 degrees Celsius. Can be adjusted with.

Specifically, the temperature control external air supply unit 460 may include an external air supply pipe for supplying external air and an external air supply blower installed in the external air supply pipe.

As such, according to the fourth embodiment of the present invention, since the heating device 400 is not always operated and is used auxiliary depending on the temperature of the exhaust gas supplied to the decomposition chamber 500 through the front branch flow path 640. The operation rate of the heating device 400 can be greatly reduced. That is, the consumption of fuel or other energy due to the use of the heating device 400 can be reduced.

Further, according to the fourth embodiment of the present invention, the temperature of the exhaust gas supplied to the decomposition chamber 500 through the front branch flow path 640 using the temperature control external air supply 460 is rather than the urea decomposition temperature range. If high, the outside air may be supplied to the front branch flow path 640 to lower the temperature of the exhaust gas.

By such a configuration, the selective non-catalytic reduction and selective catalytic reduction complex system 104 according to the fourth embodiment of the present invention can more efficiently supply a reducing agent.

Hereinafter, a selective non-catalytic reduction and selective catalytic reduction system 105 according to a fifth embodiment of the present invention will be described with reference to FIG. 5.

As shown in FIG. 5, the selective non-catalytic reduction and selective catalytic reduction system 105 according to the fifth embodiment of the present invention is the decomposition chamber 500 and the second injection unit 520 in the above-described fourth embodiment. Further comprises an additional reducing agent supply flow path 652. The urea supply unit 810 supplies urea only to the decomposition chamber 500. That is, unlike the fourth embodiment, in the fourth embodiment of the present invention, the ammonia generated in the decomposition chamber 500 without the injection of the aqueous urea solution is directly supplied from the urea supply unit 810 in the second injection unit 520. It will inject gas.

By such a configuration, the selective non-catalytic reduction and selective catalytic reduction complex system 105 according to the fifth embodiment of the present invention can stably supply a reducing agent.

Specifically, even when the temperature of the exhaust gas generated in the combustion chamber 100 varies depending on the type of the combustion chamber 100 or the surrounding environment, the ammonia generated in the decomposition chamber 500 may be inadequate to directly decompose urea into ammonia. By using the gas in the selective non-catalytic reduction reaction, it is possible to stably supply a reducing agent for the selective non-catalytic reduction reaction.

Hereinafter, a selective non-catalytic reduction and selective catalytic reduction system 106 according to a sixth embodiment of the present invention will be described with reference to FIG. 6.

As shown in FIG. 6, the selective non-catalytic reduction and selective catalytic reduction system 103 according to the sixth embodiment of the present invention includes an exhaust passage 610 upstream of the first injector 510 in the fourth embodiment. A third injector 530 provided on the upper surface, a fourth injector 540 installed in the combustion chamber 100, and an additional reducing agent supply flow path 652 connecting the decomposition chamber 500 and the second injector 520. More).

In addition, in the sixth embodiment of the present invention, the urea supply unit 810 supplies urea to the decomposition chamber 500, the third injection unit 530, and the fourth injection unit 540. That is, unlike the fourth embodiment, in the sixth embodiment of the present invention, the ammonia generated in the decomposition chamber 500 without the injection of the urea solution is directly supplied from the urea supply unit 810 by the second injection unit 520. It will inject gas.

 Further, according to the sixth embodiment of the present invention, the first injector 510 and the third injector 530 inject a reducing agent to be used for the selective catalytic reduction reaction, and the second injector 520 and the fourth injector. The sand 540 sprays a reducing agent to be used for the selective non-catalytic reduction reaction. The first injector 510 and the third injector 530, and the second injector 520 and the fourth injector 540 may be selectively used.

Specifically, when the temperature of the exhaust gas generated in the combustion chamber 100 fluctuates depending on the type of the combustion chamber 100 or the surrounding environment and is suitable to decompose urea directly into ammonia, the urea aqueous solution through the fourth injection unit 540. And spray it, it can be used as a reducing agent for the selective non-catalytic reduction reaction.

On the contrary, if the temperature of the exhaust gas generated in the combustion chamber 100 is unsuitable to directly decompose urea into ammonia, the ammonia gas generated in the decomposition chamber 500 is injected through the second injector 520. This may be used as a reducing agent for the selective non-catalytic reduction reaction.

As such, by selectively using the second injector 520 and the fourth injector 540 according to the temperature of the exhaust gas generated in the combustion chamber 100, a stable and selective supply is provided by supplying a reducing agent suitable for the current exhaust gas temperature. It is possible to carry out a catalytic reduction reaction.

In addition, when the temperature of the exhaust gas flowing into the reactor 300 fluctuates and is suitable to decompose urea into ammonia directly, the third injection part 530 may be used in the exhaust flow path 610 upstream of the reactor 300. The sprayed aqueous urea solution can be used as a reducing agent for the selective catalytic reduction reaction. In this case, since it is not necessary to operate the heating device 400 and the blower 450, it is possible to reduce the energy consumed unnecessarily for the operation of the system.

On the contrary, when the temperature of the exhaust gas flowing into the reactor 300 fluctuates and is inappropriate to decompose urea into ammonia, the ammonia gas generated in the decomposition chamber 500 is injected through the first injector 510. And it can be used as a reducing agent for the selective catalytic reduction reaction.

As such, by selectively using the first injector 510 and the third injector 530 according to the temperature of the exhaust gas introduced into the reactor 300, a stable selective is provided by supplying a reducing agent suitable for the current exhaust gas temperature. In addition to performing the catalytic reduction reaction, the operation of the heating device 400 and the blower 450 may be minimized to reduce energy and time consumption due to the operation of the heating device 400 and the blower 450.

By such a configuration, the selective non-catalytic reduction and selective catalytic reduction complex system 106 according to the sixth embodiment of the present invention can supply the reducing agent more efficiently and stably.

Hereinafter, the heating apparatus 400 used in the first to sixth embodiments of the present invention described above with reference to FIG. 7 will be described in detail.

As described above, the heating device 400 is installed on the rear branch flow path 680 or on the front branch flow path 640 to heat up the exhaust gas moving along the rear branch flow path 680 or the front branch flow path 640. You can.

In this case, the heating device 400 may be a burner. However, when the burner is used as the heating device 400, the burner may not be burned smoothly due to insufficient oxygen content in the exhaust gas moving along the rear branch flow path 680 or the front branch flow path 640.

Accordingly, an oxygen concentration sensor 407 is provided on the rear branch flow path 680 or the front branch flow path 640, and the combustion unit supplies fuel to the heating device 400 according to the measured value of the oxygen concentration sensor 407. The combustion air supply unit 405 for supplying combustion air to the fuel supply unit 403 and the heating device 400 may be controlled. At this time, the combustion air supply unit 405 may be a blower.

As such, when the combustion air supply 405 is applied to the fourth to sixth embodiments, the selective non-catalytic reduction and selective catalytic reduction complex system 104, 105, and 106 may have at least three blowers 450, 460. 405 can be used to control the flow of exhaust gas and air.

On the other hand, the burner is not necessarily used as the heating device 400, a variety of devices known to those skilled in the art, such as an electric heater may be used as the heating device 400.

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, 104, 105, 106: Selective non-catalytic reduction and selective catalytic reduction complex system
100: combustion chamber
300: reactor
350: catalyst
400: heating device
403: fuel supply for combustion
405: combustion air supply
407: oxygen concentration sensor
450: blower
500: decomposition chamber
510: first injection unit
520: second injection unit
530: third injection unit
540: fourth injection unit
610: exhaust passage
640: forward branch path
651: reducing agent supply flow path
652: additional reducing agent supply flow path
680: rear quarter flow path
810: urea supply
880: urea storage unit
900: economizer

Claims (13)

In the selective non-catalytic reduction and selective catalytic reduction complex system for reducing the nitrogen oxide contained in the exhaust gas discharged from the combustion chamber,
An exhaust passage for discharging the exhaust gas generated in the combustion chamber;
A reactor installed on the exhaust passage to embed a catalyst for reducing nitrogen oxide contained in the exhaust gas;
A first injector installed on the exhaust passage upstream of the reactor;
A second injection unit installed in the combustion chamber;
A rear branch passage branched from the exhaust passage downstream from the reactor;
A decomposition chamber connected to the branch passage;
A reducing agent supply passage connecting the decomposition chamber and the first injection unit; And
Urea supply unit for supplying urea (urea) to at least one of the decomposition chamber and the second injection unit
Selective non-catalytic reduction and selective catalytic reduction composite system comprising a. The method of claim 1,
A heating device installed on the rear branch flow path and controlling a temperature of the exhaust gas moving along the rear branch flow path;
A blower installed on the rear branch flow path to move a portion of the exhaust gas moving along the exhaust flow path to the rear branch flow path.
Selective catalytic free reduction and selective catalytic reduction composite system further comprises. The method of claim 2,
An oxygen concentration sensor provided on the rear branch flow path;
A fuel supply unit for combustion supplying fuel to the heating device; And
Combustion air supply unit for supplying combustion air to the heating device
Selective catalytic free reduction and selective catalytic reduction composite system further comprises. The method of claim 1,
An economizer installed on the exhaust passage between the combustion chamber and the reactor to recover thermal energy from the exhaust gas moving along the exhaust passage;
Urea storage unit for storing the urea to be supplied to the urea supply unit
Selective catalytic free reduction and selective catalytic reduction composite system further comprises. The method according to any one of claims 1 to 4,
Further comprising an additional reducing agent supply passage connecting said decomposition chamber and said second injection,
And the urea supply unit supplies urea only to the decomposition chamber. The method according to any one of claims 1 to 4,
A third injector provided on the exhaust flow passage upstream of the first injector;
A fourth injection unit installed in the combustion chamber; And
An additional reducing agent supply flow path connecting the decomposition chamber and the second injector;
More,
And the urea supply unit supplies urea to the decomposition chamber, the third injector, and the fourth injector. In the selective non-catalytic reduction and selective catalytic reduction complex system for reducing the nitrogen oxide contained in the exhaust gas discharged from the combustion chamber,
An exhaust passage for discharging the exhaust gas generated in the combustion chamber;
A reactor installed on the exhaust passage to embed a catalyst for reducing nitrogen oxide contained in the exhaust gas;
A first injector installed on the exhaust passage upstream of the reactor;
A second injection unit installed in the combustion chamber;
A forward branch passage branched from the exhaust passage upstream of the reactor;
A decomposition chamber connected to the branch passage;
A reducing agent supply passage connecting the decomposition chamber and the first injection unit; And
Urea supply unit for supplying urea to at least one of the decomposition chamber and the second injection unit
Selective non-catalytic reduction and selective catalytic reduction composite system comprising a. The method of claim 7, wherein
A heating device installed on the front branch flow path and controlling a temperature of the exhaust gas moving along the front branch flow path;
A blower installed on the front branch flow path for moving a part of the exhaust gas moving along the exhaust flow path to the front branch flow path.
Selective catalytic free reduction and selective catalytic reduction composite system further comprises. The method of claim 7, wherein
And an external air supply unit for controlling the temperature of the exhaust gas moving along the front branch flow path by supplying outside air to the front branch flow path. The method of claim 8,
An oxygen concentration sensor provided on the front branch flow path;
A fuel supply unit for combustion supplying fuel to the heating device; And
Combustion air supply unit for supplying combustion air to the heating device
Selective catalytic free reduction and selective catalytic reduction composite system further comprises. The method of claim 7, wherein
An economizer installed on the exhaust passage between the combustion chamber and the reactor to recover thermal energy from the exhaust gas moving along the exhaust passage;
Urea storage unit for storing the urea to be supplied to the urea supply unit
Selective catalytic free reduction and selective catalytic reduction composite system further comprises. The method according to any one of claims 7 to 11,
Further comprising an additional reducing agent supply passage connecting said decomposition chamber and said second injection,
And the urea supply unit supplies urea only to the decomposition chamber. The method according to any one of claims 7 to 11,
A third injector provided on the exhaust flow passage upstream of the first injector;
A fourth injection unit installed in the combustion chamber; And
An additional reducing agent supply flow path connecting the decomposition chamber and the second injector;
More,
And the urea supply unit supplies urea to the decomposition chamber, the third injector, and the fourth injector.

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