JP2013245677A - Device for removing nitrogen oxide and method for removing nitrogen oxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for removing a nitrogen oxide that effectively removes a nitrogen oxide included in an exhaust gas, and to provide a method for removing the nitrogen oxide.SOLUTION: A device for removing a nitrogen oxide includes a reducing agent supplier that generates a reducing agent from an initial material by thermal reaction using the thermal energy of an exhaust gas of a first engine and a catalyst reducing section that removes the nitrogen oxide included in the exhaust gas of a second engine by catalytic reduction reaction using the reducing agent. The exhaust gas of the second engine is supplied to the catalyst reducing section without passing through the reducing agent supplier.

Description

  The present invention relates to a nitrogen oxide removing apparatus and a nitrogen oxide removing method, and more particularly to a nitrogen oxide removing apparatus and a nitrogen oxide removing method that effectively remove nitrogen oxide contained in engine exhaust gas. .

The diesel engine generates nitrogen oxides (hereinafter referred to as NOx) mainly composed of NO and NO ₂ during the combustion process inside the cylinder. Since NOx is a typical pollutant, various studies for removing NOx generated in the combustion process are being conducted.

  In particular, the International Maritime Oraganization (IMO), which is part of the United Nation (UN), regulates nitrogen oxide emissions from ships. According to the Chapter 6 of Annex 73 of the Marine Pollution Treaty (MARPOL Treaty) 73/78, vessels that have been sailing on the coast from 2016 need to keep nitrogen oxide emissions below a certain level.

  As a method for removing nitrogen oxides, a selective catalytic reduction (hereinafter referred to as SCR) method is widely used. SCR is a method of converting nitrogen oxides into stable molecular molecules by injecting nitrogen oxides and a reducing agent into a catalyst and inducing a catalytic reduction reaction between the nitrogen oxides and the reducing agent. At this time, a titanium-vanadium catalyst is used as the catalyst, and ammonia is mainly used as the reducing agent.

  On the other hand, ammonia is difficult to handle because it is a toxic substance with a strong odor. Therefore, when ammonia is used as the reducing agent of the SCR, a separate device such as a leak detection sensor, a double outer wall, or a ventilator is required in preparation for ammonia leakage, and the storage tank in which ammonia is stored is It needs to be installed in an open area (for example, an open area on the upper deck of a ship). Therefore, recently, a method of generating ammonia by injecting an aqueous urea solution (hereinafter referred to as urea water) that is easy to handle into high-temperature exhaust gas and thermally decomposing the injected urea water has been proposed. The general contents of the nitrogen oxide removing apparatus using ammonia are disclosed in Korean Patent No. 10-2012-00305533 (see Patent Document 1).

  At this time, in order to stably generate ammonia from the urea water, it is required that the exhaust gas from which the urea water is injected has a temperature within a certain range (about 320 ° C. to 400 ° C.). In addition, when the temperature of the exhaust gas into which urea water is injected is lower than the required temperature, the urea water is not completely decomposed, and many by-products such as biuret and cyanuric acid are generated. This can lead to a reduction in nitrogen oxide removal performance.

Republic of Korea Patent No. 10-2012-00305533

  The objective of this invention is providing the nitrogen oxide removal apparatus and nitrogen oxide removal method which improve the reducing agent production | generation efficiency and suppress the production | generation of a by-product.

  Another object of the present invention is to provide a nitrogen oxide removing apparatus and a nitrogen oxide removing method that include a common denitrification apparatus for a plurality of engines and reduce installation and production costs.

  Still another object of the present invention is to provide a nitrogen oxide removing device and a nitrogen oxide removing method that minimize the reduction in driving force of a turbocharger turbine.

  A further object of the present invention is to provide a nitrogen oxide removing device and a nitrogen oxide removing method that minimize the space capacity inserted between the engine and the supercharger turbine.

  Still another object of the present invention is to provide a nitrogen oxide removing apparatus and a nitrogen oxide removing method provided with a porous inner cylinder that suppresses the formation and solidification of by-products.

  A still further object of the present invention is to provide a nitrogen oxide removing apparatus including a static mixer that forms a transverse swirling motion and a longitudinal vortex in a double flow to improve the homogeneity of exhaust gas and the uniformity of flow velocity distribution, and The object is to provide a method for removing nitrogen oxides.

  The nitrogen oxide removing apparatus according to the present invention includes a reducing agent supplier that generates a reducing agent from an initial material by a thermal reaction using thermal energy of exhaust gas from a first engine; and a catalytic reduction reaction using the reducing agent. A catalyst reduction unit that removes nitrogen oxides contained in the exhaust gas of the second engine is included, and the exhaust gas of the second engine is provided to the catalyst reduction unit without passing through the reducing agent supplier.

  As an example, the exhaust gas of the first engine is hotter than the exhaust gas of the second engine.

  As an embodiment, the first engine is a ship power generation engine, and the second engine is a ship propulsion engine.

  As an embodiment, the upstream is connected to the exhaust path of the second engine (hereinafter referred to as the second exhaust path), the downstream is connected to the catalytic reduction unit, and the reducing agent feeder is connected between the upstream and the downstream. It further includes a vent pipe into which an exhaust path (hereinafter referred to as a first exhaust path) joins.

  As an embodiment, the reducing agent supplier exhausts the mixed gas in which the exhaust gas of the first engine and the reducing agent are mixed from the first exhaust path, and the exhausted mixed gas is the second gas. Together with the exhaust gas of the second engine flowing in from the exhaust passage, the exhaust gas is provided to the catalyst reduction section through the vent pipe.

  As an embodiment, the catalytic reduction unit includes a static mixer that mixes the exhausted mixed gas and the exhaust gas of the second engine, and the static mixer includes the exhausted mixed gas and the second mixed gas. A screw plate that induces a vortex flow in the exhausted mixed gas or the exhaust gas of the second engine while the exhaust gas of the engine passes through the static mixer.

  The embodiment further includes a valve that selectively guides the exhaust gas of the second engine to the catalyst reduction unit or the external exhaust port.

  The nitrogen oxide removing apparatus according to the present invention includes an exhaust pipe for guiding engine exhaust gas to a turbocharger turbine; a dynamic pressure generator for extracting a part of the exhaust gas flowing through the exhaust pipe; and the extracted gas; A reductant supplier for mixing with a reductant and providing the exhaust pipe; and a nitrogen oxidizer included in the exhaust gas by a catalytic reduction reaction using the reductant, connected to a rear end of the turbocharger turbine; The bleed gas provided to the exhaust pipe is sequentially guided to the supercharger turbine and the SCR reactor through the exhaust pipe.

  As an embodiment, the dynamic pressure generator bleeds a part of the exhaust gas from the downstream side of the exhaust pipe, and the reducing agent supplier sends the extracted gas and the reducing agent upstream of the exhaust pipe. Provide to the side.

  As an embodiment, the dynamic pressure generator includes a dynamic pressure plate that extracts a part of the exhaust gas and supplies it to the reducing agent supplier; and a rotating shaft that couples the dynamic pressure plate to the exhaust pipe.

  As an embodiment, the reducing agent supplier generates the reducing agent from an initial material by a thermal reaction using thermal energy of the extracted gas.

  As an example, the reducing agent supplier is located between a nozzle for providing the initial material to a thermal reaction region; and an outer cylinder of the reducing agent supplier and the thermal reaction region, and has a plurality of holes on the surface. Including a porous inner cylinder.

  As an embodiment, the reducing agent supplier further includes a swirler that generates a swirling force in the space inside the porous inner cylinder.

  As an embodiment, the screw plate includes a static mixer that mixes the reducing agent and the exhaust gas, and the static mixer induces a vortex in the exhaust gas while the exhaust gas passes through the static mixer. including.

  The nitrogen oxide removing apparatus according to the present invention includes a static mixer that induces a vortex in a fluid and mixes the fluid; and an SCR reactor that removes nitrogen oxide contained in the fluid by a catalytic reduction reaction, The static mixer includes an inflow portion that receives the fluid; a discharge portion that discharges the fluid; and a screw plate that induces a vortex in the fluid while the fluid moves from the inflow portion to the discharge portion.

  As an example, the vortex is a double vortex including a longitudinal vortex and a transverse swirl.

  As an example, the screw plate has a hollow center.

  As an embodiment, the outer edge portion of the screw plate is in contact with the inner edge portion of the outer cylinder of the static mixer.

  As an example, the fluid includes engine exhaust gas and a reducing agent for the catalytic reduction reaction.

  For example, the static mixer may further include a reducing agent supplier that provides the reducing agent, and the static mixer may be installed between the reducing agent supplier and the SCR reactor.

  As an example, the reducing agent is ammonia gas, and the reducing agent supplier generates the reducing agent from urea by a thermal reaction using thermal energy of the exhaust gas.

  The nitrogen oxide removing apparatus according to the present invention includes a reducing agent supplier that generates a reducing agent from an initial substance by a thermal reaction using thermal energy of exhaust gas, and the reducing agent supplier includes the reducing agent supplier. A porous inner cylinder that is installed in a space apart from the wall of the reducing agent feeder and has a plurality of holes through which the exhaust residue passes; and a nozzle that provides the initial substance.

  As an embodiment, the nozzle injects the initial substance toward the inside of the porous inner cylinder.

  As an example, the plurality of holes are circular or rod-shaped.

  As an embodiment, the area of the plurality of holes becomes smaller as it is closer to the nozzle.

  As an embodiment, the reducing agent supplier further includes a swirler that generates a swirling force in the air inside the porous inner cylinder.

  The embodiment further includes an SCR reactor that removes nitrogen oxides by a catalytic reduction reaction using the reducing agent.

  As an example, the initial material is urea and the reducing agent is ammonia gas.

  The method for removing nitrogen oxides according to the present invention includes a step of generating a reducing agent from an initial material by a thermal reaction using thermal energy of exhaust gas of a first engine; and a second engine by a catalytic reduction reaction using the reducing agent. Removing nitrogen oxides contained in the exhaust gas.

  As an embodiment, the nitrogen oxide removing device has an upstream connected to a second exhaust passage that exhausts exhaust gas of the second engine, and a downstream connected to a catalytic reduction unit in which the catalytic reduction reaction is performed. A vent pipe through which the first exhaust path into which the reducing agent flows flows between the first and the downstream.

  As an example, the exhaust gas of the first engine is hotter than the exhaust gas of the second engine.

  ADVANTAGE OF THE INVENTION According to this invention, the nitrogen oxide removal apparatus and nitrogen oxide removal method which improve a reducing agent production | generation efficiency and suppress the production | generation of a by-product are provided.

  Moreover, since the nitrogen oxides of a plurality of engines can be removed using a common denitrification device, the installation and production costs of the nitrogen oxide removal device are reduced.

  In addition, the reduction of the driving force of the supercharger turbine of the nitrogen oxide removing device is minimized.

  Further, the space capacity inserted between the engine and the turbocharger turbine is minimized, and the engine turbulence phenomenon is reduced.

  Moreover, the nitrogen oxide removal apparatus and the nitrogen oxide removal method which comprise the porous inner cylinder which suppresses the production | generation and solidification of a by-product are provided.

  Further, the uniformity of the exhaust gas and the uniformity of the flow velocity distribution are improved.

It is a figure which shows the nitrogen oxide removal apparatus which concerns on 1st Example of this invention. It is a figure which shows the specific Example of the dynamic pressure generator and reducing agent supply apparatus which are shown in FIG. FIG. 3 is a development view showing an embodiment of the porous inner cylinder shown in FIG. 2. FIG. 3 is a development view showing an embodiment of the porous inner cylinder shown in FIG. 2. It is a figure which shows the Example of the swirler shown in FIG. It is sectional drawing which shows the Example of the static mixer shown in FIG. It is the top view which looked at the screw board shown in FIG. 6 from upper direction. It is a figure which shows the nitrogen oxide removal apparatus which concerns on 2nd Example of this invention. It is a figure which shows the specific Example of the reducing agent supply device shown in FIG. It is a flowchart which shows the nitrogen oxide removal method which concerns on this invention.

  Both the foregoing general description and the following detailed description are exemplary in order to provide an additional description of the claimed invention. Accordingly, the present invention is not limited to the embodiments described herein, and may be embodied in other forms. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

  In this specification, when a part is referred to as including a component, this means that it may further include other components. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  Nitrogen oxide removal apparatus using the selective catalytic reduction method becomes a problem when the exhaust gas temperature of the applied engine is relatively low. For example, the exhaust gas of a marine propulsion engine is subject to heat loss while passing through the supercharger turbine, and the temperature of the exhaust gas after passing through the supercharger turbine is lowered to about 250 ° C. In this case, the temperature of the exhaust gas cannot reach a temperature suitable for generating a reducing agent (for example, ammonia) (about 320 ° C. to 400 ° C.), so that a large amount of by-products are generated in the reducing agent generation process. To occur.

  On the other hand, the related prior document, Korean Patent No. 10-2012-0030553, pays attention to the fact that the temperature of the exhaust gas before passing through the turbocharger turbine is relatively high. A method for extracting ammonia from a turbine to generate ammonia is disclosed. However, in such a method, a part of the exhaust gas is discharged from the catalytic reaction device (or the SCR reactor) without passing through the supercharger turbine, so that the power of the supercharger turbine is reduced. is there.

  The present invention provides a nitrogen oxide removal apparatus and a nitrogen oxide removal method that provide sufficiently hot exhaust gas suitable for the production of a reducing agent and that minimizes power reduction of a turbocharger turbine.

  FIG. 1 is a view showing a nitrogen oxide removing apparatus according to a first embodiment of the present invention. Referring to FIG. 1, the nitrogen oxide removing apparatus 100 includes an initial material tank 120, a pump 121, a reducing agent supplier 130, an exhaust pipe P1, a dynamic pressure generator 140, and first and second valves 170a. 170b, static mixer 180, and SCR reactor 190. Moreover, it has the engine 110, the receiver 111, the air supply cooler 161, the blower 160, and the supercharger turbine 150 as a peripheral component of the nitrogen oxide removal apparatus 100.

  The supply air M1 flows from the outside to start the engine. The supply air M1 is sent to the supply air cooler 161 via the blower 160. The supply air cooler 161 cools the supplied supply air and sends it to the engine 110.

  The engine 110 burns fuel by using the supplied air supply, and exhausts exhaust gas generated during the combustion process to the receiver 111. As an example, engine 110 may be a two-cycle diesel engine. Further, as an example, the engine 110 may be a marine vessel propulsion engine. In the following description, it is assumed that the engine 110 is a marine vessel propulsion engine.

  The receiver 111 temporarily stores the exhaust gas that has come out of the engine 110, and thereafter sends it to the exhaust pipe P1.

  The exhaust pipe P1 guides the exhaust gas that has been sent to the supercharger turbine 150. At this time, a part of the exhaust gas flowing through the exhaust pipe P <b> 1 may be extracted by the dynamic pressure generator 140.

  The dynamic pressure generator 140 is configured to extract a part of the exhaust gas from the exhaust pipe P1. As an example, the dynamic pressure generator 140 may be opened and closed according to the ship operation mode. For example, when a ship operates in a sea area where the content of nitrogen oxides is regulated (hereinafter referred to as a regulated sea area), the dynamic pressure generator 140 is opened to remove nitrogen oxides in the exhaust gas. Then, the dynamic pressure generator 140 extracts a part of the exhaust gas from the exhaust pipe P1 through the opened space. On the other hand, when the ship operates in a place that is not a regulated sea area, the dynamic pressure generator 140 is closed and the dynamic pressure generator 140 does not extract the exhaust gas. In this case, all the exhaust gas passing through the exhaust pipe P <b> 1 is guided to the supercharger turbine 150.

  The specific configuration and operation of the dynamic pressure generator 140 will be described later with reference to FIG.

  The reducing agent supplier 130 provides the reducing agent and mixes the gas extracted by the dynamic pressure generator 140 with the reducing agent. The reducing agent supplier 130 returns a mixed gas of the extracted gas and the reducing agent (hereinafter referred to as a mixed gas) to the exhaust pipe P1. As will be described later, the reducing agent in the returned mixed gas is used for the catalytic reduction reaction in the SCR reactor 190. And the returned mixed gas is induced | guided | derived to the supercharger turbine, merges with exhaust gas, and is used for the drive of a supercharger turbine.

  As an example, the reducing agent supplier 130 may generate the reducing agent using the thermal energy of the extracted gas.

  As an example, the reducing agent supplier 130 can generate the reducing agent from the initial material by a thermal reaction using the thermal energy of the extracted gas. In this case, the nitrogen oxide removing apparatus 100 stores the initial substance in the initial substance tank 120 and provides the initial substance to the reducing agent supplier 130 via the pump 121.

  As an example, the reducing agent provided by the reducing agent supplier 130 may be ammonia, and the initial material may be urea. In this case, the initial substance tank 120 stores urea, and the stored urea is provided to the reducing agent supplier 130 via the pump 121. At this time, urea may be provided in the form of an aqueous solution (urea water). The reducing agent supplier 130 injects urea toward the hot extracted gas, and ammonia is generated from the urea by a thermal reaction using the thermal energy of the extracted gas.

  A specific description of the configuration and operation of the reducing agent supplier 130 will be described later with reference to FIGS.

  According to the configuration of the dynamic pressure generator 140 and the reducing agent supplier 130 as described above, the exhaust debris for generating the reducing agent is extracted before the supercharger turbine 150. When the exhaust gas passes through the supercharger turbine 150, a part of the thermal energy of the exhaust gas is consumed to drive the supercharger turbine 150. Therefore, the temperature of the exhaust gas that has passed through the supercharger turbine 150 is relatively low. Therefore, in the present invention, by extracting the exhaust gas at the front stage of the supercharger turbine 150, it is possible to generate the reducing agent using the exhaust gas having a relatively high temperature. Can be improved.

  As an example, when ammonia (reducing agent) is generated from urea (initial substance), exhaust gas is extracted before the supercharger turbine 150, and urea is injected into the extracted gas. The injected urea is relatively completely thermally decomposed by the high-temperature exhaust gas, and generation of by-products such as biuret and cyanuric acid can be minimized.

  Further, after the reducing agent is generated, the extracted exhaust gas is returned to the exhaust pipe P1 together with the reducing agent. The returned exhaust gas merges with other exhaust gas in the exhaust pipe P <b> 1 and is guided to the supercharger turbine 150 to drive the supercharger turbine 150. That is, since the exhaust gas extracted by the dynamic pressure generator 140 is also guided to the supercharger turbine 150 after the reducing agent is generated, a reduction in power of the supercharger turbine 150 can be minimized.

  Further, since the only component disposed between the receiver 111 and the supercharger turbine 150 is the reductant supplier 130 having a relatively small space capacity, the engine turbulence phenomenon can be minimized. It should be noted that when the SCR reactor 190 is disposed between the receiver 111 and the turbocharger turbine 150 in order to use high-temperature exhaust gas, the supercharging capacity is increased due to the very large space capacity of the SCR reactor 190. The driving of the mechanical turbine 150 may not be able to follow engine load fluctuations. This can also lead to temporary engine upsets. However, according to the present invention, only the reducing agent supplier 130 having a small space capacity is disposed between the receiver 111 and the supercharger turbine 150, so that the supercharger turbine 150 can quickly react to engine load fluctuations. Can follow.

  The exhaust gas guided to the supercharger turbine 150 passes through the supercharger turbine 150 and then reaches the first valve 170a through the exhaust pipe P2. At this time, the exhaust gas consumes a part of energy while passing through the supercharger turbine 150 and drives the supercharger turbine 150.

  The first valve 170a guides the exhaust gas to one of the exhaust pipes P3 and P5. As an example, the exhaust pipe through which the first valve 170a induces gas may be determined according to the ship operation information. For example, in a sea area where the emission of nitrogen oxides is regulated, the first valve 170a guides the exhaust gas to the exhaust pipe P3 in order to remove the nitrogen oxide from the exhaust gas. On the other hand, in the sea area where the emission of nitrogen oxides is not regulated, the first valve 170a guides the exhaust gas to the exhaust pipe P5 in order to discharge the exhaust gas as it is.

  The exhaust gas guided to the exhaust pipe P3 by the first valve 170a is sent to the static mixer 180.

  The static mixer 180 mixes the reducing agent contained in the exhaust gas and the exhaust gas in order to improve the nitrogen oxide removal efficiency of the SCR reactor 190. Due to the mixing action in the static mixer 180, the reducing agent can be more uniformly distributed in the exhaust gas.

  As an example, the static mixer 180 induces a swirl motion on the plane of flow with respect to the exhaust gas. Therefore, the exhaust gas sent to the SCR reactor 190 is guided so that the flow velocity on the flow cross section becomes more uniform.

  A specific description of the configuration and operation of the static mixer 180 will be described later with reference to FIG.

  The exhaust gas that has passed through the static mixer 180 is sent to the SCR reactor 190.

  The SCR reactor 190 removes nitrogen oxides contained in the sent exhaust gas by a selective catalytic reduction reaction. At this time, the reducing agent contained in the exhaust gas is used as a reducing agent in the selective catalytic reduction reaction. The SCR reactor 190 includes a catalyst part 191 therein.

  Since the specific configuration and operation of the SCR reactor 190 are widely known in the art, description thereof will be omitted.

  According to the configuration as described above, since the relatively high-temperature exhaust gas is used for providing the reducing agent, the generation efficiency of the reducing agent is increased. Further, since the exhaust gas extracted for providing the reducing agent is again guided to the supercharger turbine 150, a reduction in power of the supercharger turbine 150 is minimized. Further, since only the reducing agent supplier 130 having a small space capacity is disposed between the receiver 111 and the supercharger turbine 150, the temporary engine turbulence phenomenon is minimized.

  FIG. 2 is a diagram showing a specific embodiment of the dynamic pressure generator and the reducing agent supplier shown in FIG. Referring to FIG. 2, the dynamic pressure generator 140 includes a dynamic pressure plate 141 and a rotating shaft 142. The reducing agent supplier 130 includes an inflow part 135, a discharge part 136, and an outer cylinder 133, and includes a nozzle 131, a swirler 132, and a porous inner cylinder 134 inside.

  The dynamic pressure generator 140 extracts a part of the exhaust gas flowing through the exhaust pipe P1 and provides it to the reducing agent supplier. At this time, the dynamic pressure plate 141 is installed in the middle of the exhaust gas passage. Further, in order to extract the exhaust gas, the dynamic pressure plate 141 is opened toward the exhaust pipe P1, and exhaust debris flows from the opened portion of the dynamic pressure plate 141. Generally, when the dynamic pressure plate 141 is installed in the middle of an exhaust gas passage having kinetic energy, a high dynamic pressure is applied to the opening of the dynamic pressure plate 141. At this time, the dynamic pressure generator 140 extracts the gas in the exhaust pipe P1 into the dynamic pressure generator 140 using the dynamic pressure applied to the opening of the dynamic pressure plate 141. According to the configuration of the dynamic pressure plate 141 as described above, when the exhaust gas Mp1 flows from the upstream side of the exhaust pipe P1, a part of the flowing exhaust gas Mp3 is extracted into the dynamic pressure generator 140 by the dynamic pressure plate 141. The remaining exhaust gas Mp2 is exhausted downstream of the exhaust pipe P1.

  The rotating shaft 142 serves as a rotating shaft for rotating the dynamic pressure plate 141 by coupling the dynamic pressure plate 141 to the exhaust pipe P1. That is, the dynamic pressure plate 141 rotates around the rotation shaft 142 and opens and closes toward the exhaust pipe P1.

  On the other hand, the configuration in which the dynamic pressure generator 140 extracts the exhaust gas flowing through the exhaust pipe P1 using the dynamic pressure plate 141 and the rotating shaft 142 has been described above. Note that the present invention is not limited to this, and the dynamic pressure generator 140 extracts a part of the exhaust gas flowing through the exhaust pipe P1 using other means to reduce the reductant supplier. 130 may be provided.

  The reducing agent supplier 130 receives the exhaust gas extracted by the dynamic pressure generator 140 from the inflow portion 135. The reducing agent supplier 130 can generate the reducing agent from the initial material by a thermal reaction using the thermal energy of the extracted exhaust gas. In addition, the exhaust gas extracted in the outer cylinder 133 of the reducing agent supplier 130 is mixed with the reducing agent, and the exhaust gas Mp4 mixed with the reducing agent is returned from the discharge unit 136 to the exhaust pipe P1. The returned exhaust gas Mp4 merges with the exhaust gas Mp1 flowing through the exhaust pipe P1.

  Hereinafter, the detailed configuration and operation of the reducing agent supplier 130 will be described by taking as an example the case where the reducing agent (ammonia) is generated from the initial substance (urea).

  The nozzle 131 obtains urea M2 from the initial material tank 120 via the pump 121. As an example, in this case, the urea M2 may be in an aqueous solution (urea water) state. The nozzle 131 injects or provides urea M2 toward the inside of the porous inner cylinder 134.

  The swirler 132 generates a swirling force on the fluid (gas or liquid) inside the porous inner cylinder 134. This improves the rate at which the injected urea mixes with the exhaust gas, evaporates or heats. The specific configuration and operation of the swirler 132 will be described later with reference to FIG.

  The porous inner cylinder 134 is a structure surrounding a certain area inside the reducing agent supplier 130. The porous inner cylinder 134 has a plurality of holes penetrating the surface. The plurality of holes serve as a passage through which exhaust debris between the porous inner cylinder 134 and the outer cylinder 133 flows into the porous inner cylinder 134.

  On the other hand, since urea is injected from the nozzle 131 to the inside of the porous inner cylinder 134, the exhaust gas flowing in from the hole of the porous inner cylinder 134 is injected in the inner area of the porous inner cylinder 134 (hereinafter referred to as a thermal reaction area). Contact with urea. And exhaust gas provides the thermal energy required for the thermal reaction which produces | generates ammonia from urea.

  The porous inner cylinder 134 surrounds a region where urea is injected, thereby preventing urea and by-products (for example, cyanuric acid) from coming into contact with the outer cylinder 133. As a result, urea and by-products are prevented from solidifying and adhering to the outer cylinder 133 having a relatively low temperature.

  Further, since the inside and outside of the porous inner cylinder 134 are surrounded by high-temperature exhaust gas, the surface temperature of the porous inner cylinder 134 is kept at a high temperature close to the temperature of the exhaust gas. Therefore, even if urea or a by-product comes into contact with the porous inner cylinder 134, urea or a by-product is converted into ammonia without solidifying due to the high temperature of the porous inner cylinder 134.

  Further, the porous inner cylinder 134 guides a path along which the exhaust debris moves so that the exhaust debris merges with urea, and the exhaust debris flowing into the porous inner cylinder 134 is compared from the inflow portion 135 to the discharge portion 136. Help to flow evenly. As a result, the exhaust gas can be easily mixed with ammonia or urea by the porous inner cylinder 134.

  As an example, the porous inner tube 134 may have a cylindrical shape having a plurality of holes on the surface.

  An exemplary configuration of the porous inner cylinder 134 will be described later with reference to FIGS. 3 and 4.

  On the other hand, in this embodiment, the dynamic pressure generator 140 extracts the exhaust gas from the downstream of the exhaust pipe P1, and the reducing agent supplier 130 mixes the reducing agent with the extracted gas, and exhausts the mixed gas. Return to the upstream of the pipe P1. The scope of the present invention is not limited to this, and the dynamic pressure generator 140 bleeds exhaust gas from an arbitrary portion of the exhaust pipe P1, and the reducing agent supplier 130 also includes the exhaust pipe P1. It is possible to return the mixed gas to any point. For example, the dynamic pressure generator 140 extracts the exhaust gas from the upstream side of the exhaust pipe P1, the reducing agent supplier 130 mixes the reducing agent with the extracted gas, and the mixed gas is downstream of the exhaust pipe P1. Can be returned.

  3 and 4 are development views showing an embodiment of the porous inner cylinder shown in FIG. Referring to FIG. 3, the porous inner cylinder 134 includes an inner cylinder surface 134a and a plurality of circular holes. Referring to FIG. 4, the porous inner cylinder 134 includes an inner cylinder surface 134a and a plurality of rod-shaped holes.

  FIG. 3 is a developed view of the first embodiment of the porous inner cylinder 134. The porous inner cylinder 134 may be cylindrical. If the cylindrical porous inner tube 134 is cut in the longitudinal direction and developed, a configuration as shown in FIG. 3 is obtained. The porous inner cylinder 134 includes a plurality of holes on the inner cylinder surface 134a. The hole 134b on the inner cylinder surface 134a is circular, and the exhaust gas flows from the outside to the inside of the porous inner cylinder 134 through the hole 134b.

  As an example, the size of the plurality of holes on the inner cylindrical surface 134a may increase as the distance from the nozzle 131 (see FIG. 2) increases. Exhaust gas passing between the porous inner cylinder 134 and the outer cylinder 133 (see FIG. 2) flows in the direction toward the nozzle 131. Then, the exhaust gas flows into the porous inner cylinder 134 from the hole on the inner cylinder surface 134a while flowing. Therefore, the closer to the nozzle 131, the higher the density of exhaust gas between the porous inner cylinder 134 and the outer cylinder 133. For this reason, in order to make the amount of exhaust gas flowing into the porous inner cylinder 134 from each hole uniform, the radius of the hole may be increased as the position of the hole is further away from the nozzle 131.

  FIG. 4 is a developed view of the second embodiment of the porous inner cylinder 134. Similar to the above, the porous inner tube 134 may be cylindrical. If the cylindrical porous inner tube 134 is cut in the longitudinal direction and developed, a form as shown in FIG. 4 is obtained. The porous inner cylinder 134 includes a plurality of holes on the inner cylinder surface 134a, and the exhaust gas flows from the outside into the inside of the porous inner cylinder 134.

  On the other hand, in the second embodiment of the porous inner cylinder 134, the plurality of holes on the inner cylinder surface 134a have a rod shape.

  As an example, the size of the plurality of holes on the inner cylindrical surface 134a may be increased as the distance from the nozzle 134 (see FIG. 2) increases. For example, the holes 134b, 134c, and 134d are sequentially arranged so as to be far away from the nozzle 131. In this case, the hole 134b closest to the nozzle 131 has the narrowest width w1, and the hole 134d farthest from the nozzle 131 is configured to have the widest width w3. On the other hand, the hole 134c located in the middle has an intermediate width w2.

  The specific examples of the porous inner cylinder 134 have been described above. Note that this is an exemplification, and the porous inner tube 134 of the present invention is not limited to that shown in FIGS. 3 and 4. For example, the porous inner cylinder 134 may be a square cylinder or a triangular cylinder instead of a cylinder. The holes on the inner cylindrical surface 134a may have various shapes and sizes.

  FIG. 5 is a diagram showing an embodiment of the swirler shown in FIG. Referring to FIG. 5, the swirler 132 (see FIG. 2) includes an outer fixing ring 132c, an inner fixing ring 132d, a plurality of wings 132a, and a ventilation space 132b between the wings.

  The outer fixing ring 132c and the inner fixing ring 132d fix the plurality of wings 132a.

  The ventilation space 132b provides a space through which the waste can pass partially through the front and back surfaces of the swirler.

  The wing 132a is coupled to the outer fixing ring 132c and the inner fixing ring 132d, and forms a certain angle (hereinafter referred to as a wing angle) with the outer or inner fixing rings 132c and 132d. The blades 132a induce a swirling flow when the waste passes through the ventilation space 132b.

  As an example, the blade angle θ may be varied according to the flow rate of the exhaust gas flowing into the swirler 132 or the required strength of the swirl motion. For this purpose, the swirler 132 may be provided with a separate angle control means 132e.

  On the other hand, the swirler 132 illustrated in FIG. 5 is exemplary, and all means for inducing swirl flow in the gas passing through the swirler are included in the swirler referred to in the present invention.

  FIG. 6 is a cross-sectional view showing an embodiment of the static mixer shown in FIG. Referring to FIG. 6, the static mixer 180 includes an inflow part 181, an outer cylinder 182, a discharge part 184, and a screw plate 183 located inside the outer cylinder 182.

  The center 185 of the screw plate 183 is a hollow space. As an example, the center 185 may be a cylindrical hollow space. At this time, the center 185 is configured to form a sufficient flow cross-sectional area passage.

  As an example, the outer edge portion of the screw plate 183 may be in contact with the inner surface of the outer cylinder 182.

  When the exhaust gas Mk1 flows from the inflow portion 181, a part Mk2 flows through the center 185 and a part Mk3 is blocked by the screw plate 183. The exhaust gas Mk3 blocked by the screw plate 183 flows along the screw plate 183 while swirling. On the other hand, the exhaust gas Mk2 passing through the center 185 flows at an angle close to perpendicular to the radial direction of the screw plate 183. As a result, the flow of the exhaust gas Mk2 causes a vertical vortex Mk4 on the back surface of the screw plate 183.

  Thus, the vertical vortex Mk4 and the lateral swirl motion Mk3 are induced in the exhaust gas passing through the screw plate 183 having a hollow center. The longitudinal vortex Mk4 activates the exchange of the material and the momentum in the radial direction, and exchanges the exhaust gas flowing along the inside of the screw plate 183 and the exhaust gas flowing along the outside. . At this time, if the exhaust residue flowing along the outside of the screw plate 183 moves inward, the exhaust gas should turn at a higher speed according to the law of conservation of momentum.

  As a result, in the exhaust gas Mk1 passing through the screw plate 183, a lateral swirl motion and a vertical vortex flow are formed in a double flow, and the exhaust gas Mk1 is more easily mixed by the formed double flow. Therefore, the homogeneity in the circumferential direction and the homogeneity in the radial direction of the exhaust gas Mk1 can be simultaneously improved.

  Further, since the exhaust gas Mk5 flowing out from the discharge part 184 through the screw plate 183 becomes a turbulent state having a strong turning force, it is at the inlet of the catalyst part 191 (see FIG. 1) of the SCR reactor 182 (see FIG. 1). The flow rate can be made uniform on the flow cross section.

  FIG. 7 is a plan view of the screw plate shown in FIG. 6 as viewed from above. Referring to FIG. 7, the screw plate 183 included in the static mixer 180 has a hollow center 185 at the center.

  As described with reference to FIG. 6, a part of the exhaust gas flowing into the static mixer 180 flows straight through the center 185 and a part flows along the screw plate 183.

  As an example, the outer periphery and the inner periphery of the screw plate 183 may be circular with constant diameters r1 and r2.

  As an example, the outer diameter r1 (outer diameter) of the screw plate 183 may be the same as the inner diameter (inner diameter) of the outer cylinder 182 (see FIG. 6).

  As an example, the screw plate 183 may be installed to have a certain width l.

  FIG. 8 is a block diagram showing a nitrogen oxide removing apparatus according to the second embodiment of the present invention. Referring to FIG. 8, the nitrogen oxide removing apparatus 200 includes an initial material tank 240, a pump 241, a reducing agent supplier 250, and a catalyst reducing unit 260. As peripheral components, a low-temperature engine 210, high-temperature engines 220a, 220b, and 220c, and a plurality of valves 230a, 230b, 203c, and 230d are provided. On the other hand, the high temperature engines 220a, 220b, 220c may be plural.

  In this embodiment, for convenience of explanation, it is assumed that the high-temperature engines 220a, 220b, and 220c are 4-cycle ship power generation engines, and the low-temperature engine 210 is a 2-cycle ship propulsion engine. Note that this is not intended to limit the scope of the present invention to these engines, but is merely illustrated for convenience of explanation.

  Although not shown in FIG. 8, the exhaust passages R1, R4a, R4b, and R4c of each engine can pass through a supercharger turbine (not shown).

  When exhaust gas is discharged from the high-temperature engines 220a, 220b, and 220c, the valves 230b, 230c, and 230d selectively guide the exhaust gas to any one of a plurality of paths. For example, when a ship is operating in a sea area that regulates the emission amount of nitrogen oxides, the valves 230b, 230c, and 230d use exhaust gas as a first route in order to remove nitrogen oxides contained in the exhaust gas. Induction to R5a, R5b, R5c. On the other hand, when the ship is operating in a sea area where the emission amount of nitrogen oxides is not regulated, the valves 230b, 230c and 230d allow the exhaust gas to be discharged to the second path R6a and R6b so that the exhaust gas is discharged to the outside. , R6c.

  When the exhaust gas is guided to the first paths R5a, R5b, and R5c, the exhaust gases exhausted from the high temperature engines 220a, 220b, and 220c merge with each other in the exhaust pipe R7. The combined exhaust gas is sent to the reducing agent supplier 250.

  The reducing agent supplier 250 generates a reducing agent from the initial material, and mixes the exhaust gas and the reducing agent. The exhaust gas mixed with the reducing agent is exhausted through the exhaust path of the reducing agent supplier 250.

  As an example, the reducing agent supplier 250 may generate the reducing agent using the thermal energy of the exhaust gas.

  As an example, the reducing agent supplier 250 may generate the reducing agent from the initial material by a thermal reaction using the thermal energy of the exhaust gas. In this case, the nitrogen oxide removing apparatus 200 stores the initial material in the initial material tank 240 and provides the initial material to the reducing agent supplier 250 via the pump 241.

  As an example, the reducing agent provided by the reducing agent supplier 250 may be ammonia, and the initial material may be urea. In this case, the initial substance tank 240 stores urea and provides the urea to the reducing agent supplier 250 via the pump 241. Urea provided to the reducing agent supplier 250 may be provided in the form of an aqueous solution (urea water). The reducing agent supplier 250 injects the provided urea toward the hot exhaust gas. The injected urea is converted into ammonia by a thermal reaction using the thermal energy of the exhaust gas.

  At this time, since the exhaust gas of the high-temperature engines 220a, 220b, and 220c has a relatively high temperature, a temperature sufficient for a thermal reaction (eg, 350 ° C. or higher) even after passing through a supercharger turbine (not shown). ). As a result, urea is sufficiently converted into ammonia using the heat energy of the exhaust gas, and the production of by-products (for example, biuret or cyanuric acid) is suppressed.

  Specific contents regarding the initial material tank 240 and the pump 241 are the same as those described in FIG. The reducing agent supplier 250 according to the second embodiment of the present invention will be described in detail later with reference to FIG.

  On the other hand, the exhaust path of the reducing agent supplier 250 is connected to a separate vent pipe R2. Exhaust gas of the low-temperature engine 210 (hereinafter referred to as low-temperature exhaust gas) flows from the upstream of the vent pipe R2. The downstream side of the vent pipe R2 is connected to the catalyst reduction unit 260.

  The exhaust gas flowing along the exhaust path of the reducing agent supplier 250 flows into the vent pipe R2, and joins the low-temperature exhaust gas between the upstream and downstream of the vent pipe R2. Then, the merged exhaust gas is sent to the catalyst reduction unit 260.

  On the other hand, as an example, the low temperature exhaust gas discharged from the low temperature engine 210 may be selectively guided to the exhaust pipe R3 or the vent pipe R2 by the operation of the valve 230a. At this time, the valve 230a may be controlled with reference to the operation mode of the ship.

  The catalyst reduction unit 260 includes a static mixer 262 and an SCR reactor 261. The static mixer 262 mixes the inflowing exhaust gas, and the SCR reactor 261 removes nitrogen oxides in the exhaust gas by a selective catalytic reduction reaction using a reducing agent contained in the exhaust gas.

  On the other hand, the specific contents regarding the static mixer 262 and the SCR reactor 261 are as described above.

  Then, the exhaust gas from which the nitrogen oxides have been removed is exhausted from the outlet through the valve 270.

  According to the above-described configuration, the exhaust gas of the high-temperature engines 220a, 220b, and 220c (hereinafter referred to as high-temperature exhaust gas) is used to generate the reducing agent, so that the generation efficiency of the reducing agent is improved and the by-product is generated. The production of objects is suppressed.

  Further, since the low temperature exhaust gas is provided to the catalyst reduction unit 260 together with the high temperature exhaust gas, the reducing agent contained in the high temperature exhaust gas can be used for removing nitrogen oxides from the low temperature exhaust gas. As a result, problems (for example, generation of by-products) that occur when the reducing agent is generated using the low-temperature exhaust gas can be suppressed.

  In addition, since the common catalyst reduction unit 260 connected to the low temperature engine 210 and the high temperature engines 220a, 220b, and 220c is provided, a plurality of engines (the low temperature engine 210 and the high temperature engine 220a, 220b, 220c) can be denitrified. As a result, the equipment cost of the nitrogen oxide removing device can be reduced.

  FIG. 9 is a diagram showing a specific example of the reducing agent supplier shown in FIG. Referring to FIG. 9, the reducing agent supplier 250 includes an inflow part 251, an outer cylinder 256, a discharge part 257, a nozzle 252, a nozzle holder 253, a swirler 254, and a porous inner cylinder 255.

  The specific contents regarding the outer cylinder 256, the nozzle 252, the swirler 254, and the porous inner cylinder 255 are as described above.

  The nozzle holder 253 supports the nozzle 252. The nozzle holder 253 may be used to support the swirler.

  The inflow portion 251 is connected to the exhaust pipe R7 (see FIG. 8) and receives the exhaust gas Mr1. Part of the exhaust gas Mr1 passes through the swirler and flows into the porous inner cylinder 255. Part of the exhaust gas Mr2, Mr3, Mr4, and Mr5 flows between the porous inner cylinder 255 and the outer cylinder 256, and flows into the porous inner cylinder 255 from the hole of the porous inner cylinder 255.

  The exhaust gas Mr7 that has flowed into the porous inner cylinder 255 joins with urea to cause a thermal reaction. And exhaust gas Mr7 is mixed with the reducing agent produced | generated by a thermal reaction. At this time, the swirler 254 induces a swivel motion Mr8 in the exhaust gas so that the reducing agent is easily mixed with the exhaust gas. The exhaust gas Mr9 mixed with the reducing agent is exhausted from the discharge unit 257 to the exhaust path of the reducing agent supplier 250.

  FIG. 10 is a flowchart showing the nitrogen oxide removing method according to the present invention. Referring to FIG. 10, the method for removing nitrogen oxide includes steps S110 to S160.

  In step S110, the nitrogen oxide removing device 200 (see FIG. 8) provides the exhaust gas of the first engine to the reducing agent supplier. At this time, the first engine may be a high-temperature engine 220a, 220b, 220c (see FIG. 8). Since the exhaust gas of the first engine (hereinafter referred to as “hot exhaust gas”) has a high temperature, it is relatively high after passing through the supercharger turbine (for example, a thermal reaction for generating a reducing agent). Temperature).

  In step S120, the nitrogen oxide removing apparatus 200 generates a reducing agent from the initial material by a thermal reaction using the thermal energy of the high temperature exhaust gas. The nitrogen oxide removing device 200 mixes the high temperature exhaust gas and the reducing agent.

  As an example, the initial material may be urea and the reducing agent may be ammonia.

  A specific method for generating the reducing agent by the nitrogen oxide removing apparatus 200 is as described in FIG.

  In step S130, the nitrogen oxide removing device 200 provides exhaust gas (hereinafter, low temperature exhaust gas) of the second engine to the vent pipe R2 (see FIG. 8). The second engine may be a low temperature engine 210 (see FIG. 8). The nitrogen oxide removing device 200 provides the high-temperature exhaust gas containing the reducing agent to the vent pipe R2.

  The high temperature exhaust gas and the low temperature exhaust gas are merged in the vent pipe R2, and the nitrogen oxide removing device 200 provides the merged exhaust gas to the catalyst reduction unit 260 (see FIG. 8). At this time, the reducing agent contained in the high-temperature exhaust gas is also provided to the catalytic reduction unit 260.

  A specific method in which the low-temperature and high-temperature exhaust debris is sequentially provided to the vent pipe R2 and the catalyst reduction unit 260 is as described with reference to FIG.

  In step S140, the nitrogen oxide removing apparatus 200 mixes the high temperature exhaust gas, the low temperature exhaust gas, and the reducing agent using the static mixer 262 (see FIG. 8). The specific configuration and operation of the static mixer 262 are as described above.

  In step S150, the nitrogen oxide removing apparatus 200 provides the exhaust gas mixed by the static mixer 262 to the SCR reactor 261 (see FIG. 8). The nitrogen oxide removing device 200 removes nitrogen oxides contained in the high temperature exhaust gas or the low temperature exhaust gas by a selective catalytic reduction reaction using a reducing agent contained in the mixed exhaust gas.

  In step S160, the nitrogen oxide removing device 200 discharges the denitrified high-temperature exhaust gas or low-temperature exhaust gas to the outside through the discharge port.

  According to the configuration described above, since the high-temperature exhaust gas is used for the generation of the reducing agent, the generation efficiency of the reducing agent is improved and the generation of by-products is suppressed.

  Further, since the low temperature exhaust gas is provided to the catalyst reduction unit 260 together with the high temperature exhaust gas, a reducing agent contained in the high temperature exhaust gas can be used for removing nitrogen oxides in the low temperature exhaust gas. As a result, problems (for example, generation of by-products) that occur when a reducing agent is generated using low-temperature exhaust gas are suppressed.

  Further, since the common catalyst reduction unit 260 is provided for the low-temperature engine 210 and the high-temperature engines 220a, 220b, and 220c, exhaust gases from a plurality of engines can be denitrified through the single catalyst reduction unit 260. As a result, the equipment cost of the nitrogen oxide removing device can be reduced.

  Although the detailed description of the present invention has been described with reference to specific embodiments, the embodiments can be modified in various forms without departing from the scope of the present invention.

  For example, in the present specification, the case where the initial material is urea and the reducing agent is ammonia has been described as an example, but the present invention is also applicable to a nitrogen oxide removing apparatus using other initial materials or reducing agents. . That is, the technical idea of the present invention can be applied to any nitrogen oxide removing apparatus that requires a high temperature for generating the reducing agent.

  As another example, the first embodiment of the present invention can be applied to any nitrogen oxide removing apparatus that bleeds exhaust gas to mix the reducing agent with the exhaust gas, and the scope of the present invention extends to this.

  In addition, specific terms used herein are merely used for the purpose of describing the present invention, and are intended to limit the meaning of the present invention as described in the scope of the invention. It was not used to limit. Therefore, the scope of the present invention should not be limited to the embodiments described above, but should be determined not only by the claims but also by the equivalents of the claims of the present invention.

DESCRIPTION OF SYMBOLS 100 Nitrogen oxide removal apparatus 110 Engine or low-temperature engine 111 Receiver 120 Initial material tank 121 Pump 130 Reducing agent supply device 131 Nozzle 132 Swivel machine 133 Outer cylinder 132a Wing 132b Aeration space 132c External fixing ring 132d Internal fixing ring 132e Control means 134 Porous Inner cylinder 134a Inner cylinder plate 134b Hole 134c Hole 134d Hole 135 Inflow part 136 Discharge part 140 Dynamic pressure generator 141 Dynamic pressure plate 142 Rotating shaft 150 Supercharger turbine 160 Blower 161 Air supply cooler 170a Valve 170b Valve 180 Static mixer 181 Inflow portion 182 Outer cylinder 183 Screw plate 184 Discharge portion 185 Center 190 SCR reactor 200 Nitrogen oxide removal device 210 Engine or low temperature engine 220a High temperature engine 20b High temperature engine 220c High temperature engine 230a Valve 230b Valve 230c Valve 230d Valve 240 Initial material tank 241 Pump 250 Reducing agent supplier 251 Inflow part 252 Nozzle 254 Swivel unit 255 Porous inner cylinder 256 Outer cylinder 257 Discharge part 260 Catalyst reduction part 261 SCR reaction 262 Static mixer P1 Exhaust pipe R2 Vent pipe R7 Exhaust pipe

Claims (19)

An initial material is injected toward the exhaust gas of the first engine, and a reducing agent is generated from the injected initial material by a thermal reaction generated when the injected initial material comes into contact with the exhaust gas of the first engine. A reducing agent supplier that removes nitrogen oxides contained in the exhaust gas of the second engine by a catalytic reduction reaction using the reducing agent;
The exhaust gas of the second engine is a nitrogen oxide removing device provided to the catalytic reduction unit without passing through the reducing agent supplier.   The nitrogen oxide removing apparatus according to claim 1, wherein the exhaust gas of the first engine is at a higher temperature than the exhaust gas of the second engine. The first engine is a ship power generation engine;
The nitrogen oxide removing apparatus according to claim 2, wherein the second engine is a marine vessel propulsion engine.   The upstream is connected to the exhaust path (hereinafter referred to as the second exhaust path) of the second engine, the downstream is connected to the catalytic reduction unit, and the exhaust path (hereinafter referred to as the reducing agent supplier) between the upstream and the downstream. The nitrogen oxide removing apparatus according to claim 1, further comprising a vent pipe that joins the first exhaust path. The reducing agent supplier exhausts a mixed gas in which the exhaust gas of the first engine and the reducing agent are mixed from the first exhaust path,
5. The nitrogen oxide removing apparatus according to claim 4, wherein the exhausted mixed gas is provided to the catalyst reduction unit through the vent pipe together with the exhaust gas of the second engine flowing in from the second exhaust path. The catalytic reduction unit includes a static mixer that mixes the exhausted mixed gas and the exhaust gas of the second engine,
The static mixer is
6. A screw plate for inducing a vortex in the exhausted mixed gas or the exhaust gas of the second engine while the exhausted mixed gas and the exhaust gas of the second engine pass through the static mixer. The nitrogen oxide removing apparatus described in 1.   The nitrogen oxide removing apparatus according to claim 6, wherein the vortex is a double flow vortex including a longitudinal vortex and a lateral swirl.   The nitrogen oxide removing apparatus according to claim 6, wherein the screw plate has a hollow center.   The nitrogen oxide removing apparatus according to claim 8, wherein an outer edge portion of the screw plate is in contact with an inner edge portion of an outer cylinder of the static mixer.   The nitrogen oxide removing apparatus according to claim 1, further comprising a valve that selectively guides the exhaust gas of the second engine to the catalyst reduction unit or an external exhaust port. The reducing agent supplier is
2. The nitrogen according to claim 1, comprising a nozzle that provides the initial material to a thermal reaction region; and a porous inner cylinder that is positioned between an outer cylinder of the reducing agent supplier and the thermal reaction area and has a plurality of holes. Oxide removal equipment.   The nitrogen oxide removing apparatus according to claim 11, wherein the nozzle sprays the initial substance toward the inside of the porous inner cylinder.   The nitrogen oxide removing apparatus according to claim 11, wherein the plurality of holes are circular or rod-shaped.   The nitrogen oxide removing apparatus according to claim 13, wherein an area of each of the plurality of holes decreases with increasing proximity to the nozzle.   The nitrogen oxide removing apparatus according to claim 11, wherein the reducing agent supplier further includes a swirler that generates a swirling force in the air inside the porous inner cylinder. The initial material is urea;
The nitrogen oxide removing apparatus according to claim 1, wherein the reducing agent is ammonia gas. A nitrogen oxide removing method for a nitrogen oxide removing apparatus,
An initial material is injected toward the exhaust gas of the first engine, and a reducing agent is generated from the injected initial material by a thermal reaction generated when the injected initial material comes into contact with the exhaust gas of the first engine. And removing nitrogen oxides contained in the exhaust gas of the second engine by a catalytic reduction reaction using the reducing agent. The nitrogen oxide removing device includes:
The upstream is connected to a second exhaust path for exhausting the exhaust gas of the second engine, and the downstream is connected to a catalytic reduction section where the catalytic reduction reaction is performed, and the reducing agent flows between the upstream and the downstream The nitrogen oxide removing method according to claim 17, further comprising a vent pipe in which the first exhaust path to be joined.   The method for removing nitrogen oxides according to claim 17, wherein the exhaust gas of the first engine is higher in temperature than the exhaust gas of the second engine.

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