JP5801472B2 - Exhaust gas purification device - Google Patents

Exhaust gas purification device Download PDF

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JP5801472B2
JP5801472B2 JP2014504636A JP2014504636A JP5801472B2 JP 5801472 B2 JP5801472 B2 JP 5801472B2 JP 2014504636 A JP2014504636 A JP 2014504636A JP 2014504636 A JP2014504636 A JP 2014504636A JP 5801472 B2 JP5801472 B2 JP 5801472B2
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exhaust
exhaust gas
evaporation pipe
pipe
reducing agent
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JPWO2013136614A1 (en
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孝博 藤林
孝博 藤林
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Hitachi Zosen Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/08—Other arrangements or adaptations of exhaust conduits
    • F01N13/10—Other arrangements or adaptations of exhaust conduits of exhaust manifolds
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • F01N3/2892—Exhaust flow directors or the like, e.g. upstream of catalytic device
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2067—Urea
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/01—Engine exhaust gases
    • B01D2258/012—Diesel engines and lean burn gasoline engines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/45—Gas separation or purification devices adapted for specific applications
    • B01D2259/4566—Gas separation or purification devices adapted for specific applications for use in transportation means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9409—Nitrogen oxides
    • B01D53/9431—Processes characterised by a specific device
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/40—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a hydrolysis catalyst
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2470/00—Structure or shape of gas passages, pipes or tubes
    • F01N2470/20—Dimensional characteristics of tubes, e.g. length, diameter
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2470/00—Structure or shape of gas passages, pipes or tubes
    • F01N2470/24—Concentric tubes or tubes being concentric to housing, e.g. telescopically assembled
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2470/00—Structure or shape of gas passages, pipes or tubes
    • F01N2470/30—Tubes with restrictions, i.e. venturi or the like, e.g. for sucking air or measuring mass flow
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00—Capture or disposal of greenhouse gases
    • Y02C20/10—Capture or disposal of greenhouse gases of nitrous oxide (N2O)
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Description

本発明は、内燃機関から排出される排ガス中の窒素酸化物（以下「ＮＯx 」という。）を例えばＳＣＲ触媒等の脱硝触媒下で還元剤と反応させて還元除去する排ガス浄化装置に関するものである。   The present invention relates to an exhaust gas purifying apparatus for reducing and removing nitrogen oxide (hereinafter referred to as “NOx”) in exhaust gas discharged from an internal combustion engine by reacting with a reducing agent under a denitration catalyst such as an SCR catalyst. .

従来、例えばディーゼルエンジンの排気通路にＳＣＲ触媒が介装された脱硝反応器を設けると共に、この脱硝反応器の上流側に、尿素水等の還元剤前駆体を噴霧可能なノズルを設けた排ガス浄化装置が利用されている（例えば、特許文献１）。   Conventionally, for example, a denitration reactor in which an SCR catalyst is interposed in an exhaust passage of a diesel engine has been provided, and an exhaust gas purification system provided with a nozzle capable of spraying a reducing agent precursor such as urea water on the upstream side of the denitration reactor. An apparatus is used (for example, Patent Document 1).

上記のような装置において、ノズルから排ガス中に噴霧された尿素水は、排気通路内の温度が十分に高ければ、ＳＣＲ触媒に到達するまでの間に下記の式（１）のように加水分解され、アンモニアガス（ＮＨ3）が生成される。
（ＮＨ2）2ＣＯ＋Ｈ2Ｏ→２ＮＨ3 ＋ＣＯ2 ・・・・（１）In the apparatus as described above, the urea water sprayed into the exhaust gas from the nozzle is hydrolyzed as shown in the following formula (1) before reaching the SCR catalyst if the temperature in the exhaust passage is sufficiently high. As a result, ammonia gas (NH 3 ) is generated.
(NH 2 ) 2 CO + H 2 O → 2NH 3 + CO 2 ... (1)

そして、加水分解により発生したアンモニアガスはＳＣＲ触媒に供給され、これによりＳＣＲ触媒上でアンモニアと排ガス中のＮＯx の間に次の式（２）及び（３）のような脱硝反応が行われ、ＮＯx は窒素と水に分解されて無害化される。
４ＮＨ3＋４ＮＯ＋Ｏ2 →４Ｎ2＋６Ｈ2Ｏ・・・・（２）
２ＮＨ3＋ＮＯ＋ＮＯ2 →２Ｎ2＋３Ｈ2Ｏ・・・・（３）The ammonia gas generated by the hydrolysis is supplied to the SCR catalyst, whereby a denitration reaction such as the following formulas (2) and (3) is performed between ammonia and NOx in the exhaust gas on the SCR catalyst, NOx is decomposed into nitrogen and water and detoxified.
4NH 3 + 4NO + O 2 → 4N 2 + 6H 2 O (2)
2NH 3 + NO + NO 2 → 2N 2 + 3H 2 O (3)

このように、ＳＣＲ触媒を用いた排ガス浄化装置では、噴霧した尿素水が排気通路内を流動中に上記式（１）の加水分解反応が十分に進行する時間を確保する必要がある。   As described above, in the exhaust gas purification apparatus using the SCR catalyst, it is necessary to secure a time for the hydrolysis reaction of the above formula (1) to sufficiently proceed while the sprayed urea water flows in the exhaust passage.

そのため、従来、例えば図９に示すような、排気マニホールド１０１を備えた４気筒の舶用ディーゼルエンジン１０２においては、ターボチャージャー１０３のタービン１０３ａの上流側の排気通路１０４に設けた尿素水噴霧用のノズル１０５とＳＣＲ触媒１０６との間に、排気通路１０４よりも管路断面積を大きくした蒸発管１０７を設け、この蒸発管１０７を設けた区間の排ガスの流速を低減し、ノズル１０５から噴霧された尿素水の加水分解反応が進行する時間を確保する場合がある。   Therefore, conventionally, in a four-cylinder marine diesel engine 102 equipped with an exhaust manifold 101 as shown in FIG. 9, for example, a nozzle for spraying urea water provided in the exhaust passage 104 upstream of the turbine 103a of the turbocharger 103 An evaporation pipe 107 having a pipe cross-sectional area larger than that of the exhaust passage 104 is provided between the 105 and the SCR catalyst 106. The flow rate of the exhaust gas in the section in which the evaporation pipe 107 is provided is reduced and sprayed from the nozzle 105. There may be a case where the time for the hydrolysis reaction of urea water to proceed is secured.

また、従来、図１０に示すように、エンジンの排気系に限らず、配管内を流れる気体に対し、他の気体や液体を添加して化学反応や状態変化を生じさせる装置においても、反応時間や変化時間、気体同士の混合時間などを確保するために気体の流速を遅くする区間を設ける必要がある場合、その区間の配管の径を大きくする方法が採用されている。図１０の例では、前後の配管２０１，２０２の直径（Ｄ）に対し、気体の流速を低減させる区間（図１０中、破線Ａ〜Ｂまでの区間）の配管２０３は２倍の直径（２Ｄ）としている。   Conventionally, as shown in FIG. 10, the reaction time is not limited to the exhaust system of the engine, but also in a device that causes a chemical reaction or a state change by adding another gas or liquid to the gas flowing in the pipe. When it is necessary to provide a section in which the gas flow rate is slowed in order to secure the change time, the mixing time of the gases, etc., a method of increasing the diameter of the piping in the section is adopted. In the example of FIG. 10, the pipe 203 in the section for reducing the gas flow rate (the section from the broken lines A to B in FIG. 10) has a double diameter (2D) compared to the diameters (D) of the front and rear pipes 201 and 202. ).

このように、径の長さに２倍の差を設けた場合、例えば配管２０１内を流れる気体の速度をＶ0とすると、流速低減区間２０３内を流れる気体の速度Ｖは、Ｖ0／４に低減させることができる。 As described above, when the difference in diameter is doubled, for example, when the velocity of the gas flowing in the pipe 201 is V 0 , the velocity V of the gas flowing in the flow velocity reduction section 203 is V 0/4. Can be reduced.

しかしながら、上記のような流速低減手段を用いた場合、流速低減区間２０３の径のサイズが大きくなってしまうため、装置を小型化できないという問題がある。例えば、図９に示したような、舶用ディーゼルエンジン１０２の排気系においても、排気マニホールド１０１が大きな容積を占めている上に、さらに径のサイズが大きい蒸発管１０７を設ける必要があるため、この蒸発管１０７が装置全体の小型化を妨げる要因となっている。   However, when the flow velocity reduction means as described above is used, the size of the diameter of the flow velocity reduction section 203 becomes large, and there is a problem that the apparatus cannot be reduced in size. For example, in the exhaust system of the marine diesel engine 102 as shown in FIG. 9, the exhaust manifold 101 occupies a large volume, and it is necessary to provide an evaporation pipe 107 having a larger diameter. The evaporation tube 107 is a factor that hinders downsizing of the entire apparatus.

実公平６−４５６１７号公報Japanese Utility Model Publication No. 6-45617

本発明が解決しようとする問題点は、従来は、尿素水が加水分解される時間を十分に確保するために、尿素水噴霧ノズルから脱硝反応器に至るまでの区間の排ガスの流速を低減させる手段として、排気通路よりも径のサイズを大きくした蒸発管を使用していたので、この蒸発管が装置の小型化を妨げる要因となっていた点である。   Conventionally, the problem to be solved by the present invention is to reduce the flow rate of the exhaust gas in the section from the urea water spray nozzle to the denitration reactor in order to ensure sufficient time for the urea water to be hydrolyzed. As an means, an evaporation pipe having a diameter larger than that of the exhaust passage was used, and this evaporation pipe was a factor that hindered downsizing of the apparatus.

本発明の排ガス浄化装置は、
エンジンの排気ポートに接続された排気連絡管から排出された排ガスを集合し、排気通路に導く排気マニホールドと、前記排気通路に設けられた脱硝反応器とを備え、
前記脱硝反応器の上流側であって、かつ、前記排気通路の内部に、長手方向両端が開放された蒸発管を設けると共に、前記蒸発管内を通過する排ガスに対して還元剤、還元剤前駆体の双方または何れか一方を含む水溶液を噴霧可能なノズルを設け、
前記蒸発管の出口部の径を入口部の径よりも小さくすると共に、前記蒸発管の出口部の開放端が存在する位置を含むように前記排気通路にベンチュリを形成したことを最も主要な特徴点としている。
The exhaust gas purification apparatus of the present invention is
An exhaust manifold that collects exhaust gas discharged from an exhaust communication pipe connected to an exhaust port of the engine and guides the exhaust gas to an exhaust passage; and a denitration reactor provided in the exhaust passage;
An evaporation pipe that is upstream of the denitration reactor and that is open at both ends in the longitudinal direction is provided inside the exhaust passage, and a reducing agent and a reducing agent precursor for the exhaust gas that passes through the evaporation pipe. both or aqueous solution containing one provided sprayable nozzles,
The most important thing is that a venturi is formed in the exhaust passage so that the diameter of the outlet part of the evaporation pipe is smaller than the diameter of the inlet part and includes the position where the open end of the outlet part of the evaporation pipe exists. It is a feature point.

本発明の排ガス浄化装置は、脱硝反応器の上流側の排気通路の内部に蒸発管を設け、この蒸発管の内側を通過する排ガスに対してノズルから例えば尿素水等を噴霧するように構成したので、蒸発管内を通過する排ガスの流速が低減され、尿素水等の加水分解反応が進行する時間を十分に確保することができる。よって、本発明によれば、流速低減区間の径のサイズを従来よりも小さくすることができる。   The exhaust gas purification apparatus of the present invention is configured such that an evaporation pipe is provided inside the exhaust passage on the upstream side of the denitration reactor and, for example, urea water or the like is sprayed from the nozzle to the exhaust gas passing through the inside of the evaporation pipe. Therefore, the flow rate of the exhaust gas passing through the inside of the evaporation pipe is reduced, and a sufficient time can be secured for the hydrolysis reaction of urea water or the like to proceed. Therefore, according to the present invention, the size of the diameter of the flow velocity reduction section can be made smaller than before.

本発明の流速低減手段の構成を説明する図である。It is a figure explaining the structure of the flow velocity reduction means of this invention. 本発明の排ガス浄化装置の第１実施例の構成を示した図である。It is the figure which showed the structure of 1st Example of the exhaust gas purification apparatus of this invention. 脱硝反応器の上流側の排気通路の内部に設けた蒸発管と、尿素水噴霧用のノズルと、蒸発管の出口部の開放端付近に設けた排気通路のベンチュリを示した拡大図である。It is the enlarged view which showed the venturi of the exhaust pipe provided in the inside of the exhaust passage of the upstream of a denitration reactor, the nozzle for urea water spraying, and the exhaust passage provided in the open end vicinity of the exit part of an evaporation pipe. 本発明の排ガス浄化装置の第２実施例の構成を示した図である。It is the figure which showed the structure of 2nd Example of the exhaust gas purification apparatus of this invention. 脱硝反応器の上流側の排気通路の内部に設けた蒸発管と、尿素水噴霧用のノズルと、蒸発管の出口部の近傍に設けた尿素加水分解触媒を示した拡大図である。It is the enlarged view which showed the urea hydrolysis catalyst provided in the vicinity of the evaporating pipe provided in the inside of the exhaust passage of the upstream of a denitration reactor, the nozzle for urea water spraying, and the exit part of an evaporating pipe. 本発明の排ガス浄化装置の第３実施例の構成を示した図である。It is the figure which showed the structure of 3rd Example of the exhaust gas purification apparatus of this invention. 本発明の排ガス浄化装置の第４実施例の構成を示した図である。It is the figure which showed the structure of 4th Example of the exhaust gas purification apparatus of this invention. 本発明の排ガス浄化装置の第２実施例の変形例を示した図である。It is the figure which showed the modification of 2nd Example of the exhaust gas purification apparatus of this invention. 従来の舶用ディーゼルエンジンの構成を示した図である。It is the figure which showed the structure of the conventional marine diesel engine. 従来の流速低減手段の構成を説明する図である。It is a figure explaining the structure of the conventional flow velocity reduction means.

本発明は、エンジンの排ガス浄化装置において、管径のサイズを大きくすることなく、尿素水等の加水分解時間を確保するための低流速区間を設けるという目的を、
エンジンの排気ポートに接続された排気連絡管から排出された排ガスを集合し、排気通路に導く排気マニホールドと、前記排気通路に設けられた脱硝反応器とを備え、
前記脱硝反応器の上流側であって、かつ、前記排気通路の内部に、長手方向両端が開放された蒸発管を設けると共に、前記蒸発管内を通過する排ガスに対して還元剤、還元剤前駆体の双方または何れか一方を含む水溶液を噴霧可能なノズルを設けた構成とすることによって実現した。The object of the present invention is to provide a low flow velocity section for securing hydrolysis time of urea water or the like without increasing the size of the pipe diameter in the exhaust gas purification device of the engine.
An exhaust manifold that collects exhaust gas discharged from an exhaust communication pipe connected to an exhaust port of the engine and guides the exhaust gas to an exhaust passage; and a denitration reactor provided in the exhaust passage;
An evaporation pipe that is upstream of the denitration reactor and that is open at both ends in the longitudinal direction is provided inside the exhaust passage, and a reducing agent and a reducing agent precursor for the exhaust gas that passes through the evaporation pipe. This was realized by providing a nozzle capable of spraying an aqueous solution containing either or both of these.

前記本発明の排ガス浄化装置において、
前記蒸発管の出口部の径を入口部の径よりも小さくすると共に、前記蒸発管の出口部の開放端が存在する位置を含むように前記排気通路にベンチュリを形成した場合は、
蒸発管の出口部の径に絞りをかけることによって蒸発管内を流れる排ガスの流速を遅くすることができると共に、排気通路に形成したベンチュリの作用により、蒸発管の出口部付近の圧力が入口部付近の圧力よりも低くなるので、蒸発管内で排ガスが滞留することなく、入口部から出口部へ向かう安定した排ガスの流れができて、好適である。In the exhaust gas purification apparatus of the present invention,
When the venturi is formed in the exhaust passage so that the diameter of the outlet portion of the evaporation pipe is smaller than the diameter of the inlet portion and the position where the open end of the outlet portion of the evaporation pipe exists is present,
By restricting the diameter of the outlet part of the evaporation pipe, the flow velocity of the exhaust gas flowing in the evaporation pipe can be slowed, and the pressure near the outlet part of the evaporation pipe is increased by the action of the venturi formed in the exhaust passage. Therefore, the exhaust gas does not stay in the evaporation pipe, and a stable flow of the exhaust gas from the inlet to the outlet can be achieved.

以下、本発明を実施するための種々の形態を、図１〜図８を用いて詳細に説明する。図１は、本発明の流速低減手段の構成を説明する図である。   Hereinafter, various modes for carrying out the present invention will be described in detail with reference to FIGS. FIG. 1 is a diagram for explaining the configuration of the flow velocity reducing means of the present invention.

図１において、１は、様々な分野の装置に適用可能な本発明の流速低減手段であり、内部に気体が流れる外管２のうち、何らかの目的で流速を低減させたい区間にのみ内部に内管３を設け、流速低減区間（図１中、破線Ａ〜Ｂまでの区間）を外管２と内管３による二重管構造としている。   In FIG. 1, reference numeral 1 denotes a flow velocity reduction means of the present invention that can be applied to apparatuses in various fields. The outer tube 2 through which gas flows inside is only inside the section where the flow velocity is to be reduced for some purpose. The pipe 3 is provided, and the flow velocity reduction section (the section from the broken lines A to B in FIG. 1) has a double pipe structure with the outer pipe 2 and the inner pipe 3.

内管３は、長手方向両端が開放した筒状の部材であり、図１に示すように、下流側の出口部３ａはノズル状として入口部３ｂよりも管径に絞りをかけている。また、このノズル状の出口部３ａの開放端３ａａが存在する位置（図１中、破線Ｂで示した位置）を含むように、外管２にベンチュリ２ａを形成し、管径に絞りをかけている。   The inner pipe 3 is a cylindrical member whose both ends in the longitudinal direction are open, and as shown in FIG. 1, the outlet part 3a on the downstream side is in the form of a nozzle and has a smaller diameter than the inlet part 3b. Further, a venturi 2a is formed on the outer tube 2 so as to include a position where the open end 3aa of the nozzle-shaped outlet portion 3a exists (a position indicated by a broken line B in FIG. 1), and the tube diameter is reduced. ing.

以上のような構成とすると、外管２を流れる気体は、破線Ａの位置で、内管３の内側を通過するものと、内管３の外側を通過するものとに分かれ、破線Ｂの位置で合流することになる。   With the configuration as described above, the gas flowing in the outer tube 2 is divided into a gas passing through the inner tube 3 and a gas passing through the outer tube 3 at the position of the broken line A. Will join.

ここで、破線Ａの位置における気体の流速をＶ0とした場合、内管３の内側を通過する気体の速度Ｖと、内管３の外側を通過する気体の速度Ｖ’の関係は、Ｖ＜Ｖ0＜Ｖ’となるように外管２と内管３の各径のサイズを設定する。Here, when the flow velocity of the gas at the position of the broken line A is V 0 , the relationship between the velocity V of the gas passing inside the inner tube 3 and the velocity V ′ of the gas passing outside the inner tube 3 is V The sizes of the diameters of the outer tube 2 and the inner tube 3 are set so that <V 0 <V ′.

また、外管２において上流側の径をＤ、下流側のベンチュリ２ａの径をＤｒ、内管３において入口部３ｂの径をｄ、ノズル状の出口部３ａの径をｄｒとした場合、内管３の内側を通過する気体の速度Ｖは、Ｖ＝Ｖ0×{（ｄｒ×Ｄ）／（ｄ×Ｄｒ）}2の式で求められるので、外管２と内管３の絞りの程度（Ｄｒ／Ｄ、ｄｒ／ｄ）を適宜調節することにより、内管３内の気体の流速Ｖを所望の値に設定することができる。In the outer pipe 2, the upstream diameter is D, the diameter of the downstream venturi 2a is Dr, the diameter of the inlet 3b in the inner pipe 3 is d, and the diameter of the nozzle-shaped outlet 3a is dr. Since the velocity V of the gas passing through the inside of the tube 3 is obtained by the equation V = V 0 × {(dr × D) / (d × Dr)} 2 , the degree of restriction of the outer tube 2 and the inner tube 3 By appropriately adjusting (Dr / D, dr / d), the flow velocity V of the gas in the inner tube 3 can be set to a desired value.

また、図１の実施例では、外管２に設けたベンチュリ２ａの効果により、内管３の出口部３ａ付近の気体の圧力が入口部３ｂ付近の気体の圧力よりも低くなる。これにより、内管３内では、流体が滞留することなく、内管３の入口部３ｂから出口部３ａへと向かう安定した流れを作り出すことができる。   Further, in the embodiment of FIG. 1, due to the effect of the venturi 2 a provided in the outer tube 2, the gas pressure near the outlet portion 3 a of the inner tube 3 becomes lower than the gas pressure near the inlet portion 3 b. Thereby, in the inner pipe 3, the stable flow which goes to the exit part 3a from the inlet part 3b of the inner pipe 3 can be produced, without a fluid retaining.

以上の構成の本発明の流速低減手段によれば、管径を太くせずとも安定した流速低減区間が得られる。本発明は、流体に関する配管装置であれば、特に分野は問わず様々な装置に適用できる。本発明の効果は、反応時間や変化時間、溶解時間、蒸発時間等を確保しつつ、装置を小型化できる点にある。   According to the flow velocity reduction means of the present invention having the above configuration, a stable flow velocity reduction section can be obtained without increasing the pipe diameter. The present invention can be applied to various devices regardless of the field as long as it is a piping device related to a fluid. The effect of the present invention is that the apparatus can be miniaturized while ensuring the reaction time, change time, dissolution time, evaporation time and the like.

次に、図２は、本発明の排ガス浄化装置の第１実施例の構成を示した図である。図２において、１１は、本発明を４気筒の舶用ディーゼルエンジンに適用した排ガス浄化装置であり、エンジン１２の各シリンダヘッドに設けられた排気ポート１２ａに夫々接続された排気連絡管１３から排出された排ガスを集合し、ターボチャージャー１４のタービン１４ａの上流側の排気通路１５に導く排気マニホールド１６と、排気通路１５に設けられた脱硝反応器１７とを備えている。なお、１４ｂは、給気通路２１から給気された空気を圧縮するターボチャージャー１４のコンプレッサを示している。また、２２は、コンプレッサ１４ｂによって圧縮された空気を、給気連絡管を介してエンジン１２の各シリンダの給気ポートに分配する給気マニホールドを示している。   Next, FIG. 2 is a diagram showing the configuration of the first embodiment of the exhaust gas purifying apparatus of the present invention. In FIG. 2, reference numeral 11 denotes an exhaust gas purification device in which the present invention is applied to a four-cylinder marine diesel engine. The exhaust gas purification device 11 is discharged from an exhaust communication pipe 13 connected to an exhaust port 12 a provided in each cylinder head of the engine 12. The exhaust manifold 16 that collects the exhaust gas and leads it to the exhaust passage 15 upstream of the turbine 14 a of the turbocharger 14, and the denitration reactor 17 provided in the exhaust passage 15 are provided. Reference numeral 14b denotes a compressor of the turbocharger 14 that compresses the air supplied from the supply passage 21. Reference numeral 22 denotes an air supply manifold that distributes the air compressed by the compressor 14b to an air supply port of each cylinder of the engine 12 through an air supply communication pipe.

脱硝反応器１７よりも上流側の排気通路１５の内部には、長手方向両端が排気通路１５内に開放された蒸発管１８を設けると共に、この蒸発管１８の入口部１８ｂの近傍に、蒸発管１８内を通過する排ガスに対して、尿素水１９ａを噴霧可能なノズル１９を設けている。   In the exhaust passage 15 upstream of the denitration reactor 17, an evaporation pipe 18 whose both ends in the longitudinal direction are opened in the exhaust passage 15 is provided, and in the vicinity of the inlet portion 18 b of the evaporation pipe 18, an evaporation pipe is provided. A nozzle 19 capable of spraying urea water 19a is provided for the exhaust gas passing through the interior 18.

つまり、第１実施例は、排気通路１５が図１の外管２に、蒸発管１８が図１の内管３に相当するものである。なお、ノズル１９を、蒸発管１８の入口部１８ｂの近傍に設けた理由は、噴霧された尿素水１９ａが高温の蒸発管１８内を通過する時間を長く確保できるからである。   That is, in the first embodiment, the exhaust passage 15 corresponds to the outer tube 2 in FIG. 1, and the evaporation tube 18 corresponds to the inner tube 3 in FIG. The reason why the nozzle 19 is provided in the vicinity of the inlet 18b of the evaporation pipe 18 is that a long time for the sprayed urea water 19a to pass through the high-temperature evaporation pipe 18 can be secured.

脱硝反応器１７には、エンジン１２から排出される排ガス中に含まれ、酸性雨や光化学スモッグなどの環境汚染の原因となるＮＯx を選択的に還元除去するＳＣＲ触媒が介装されている。ＳＣＲ触媒は、例えばアルミナ、ジルコニア、バナジア／チタニア等の金属酸化物系触媒やゼオライト系触媒など所望の触媒を使用することができ、これらの触媒を組み合わせても良い。また、ＳＣＲ触媒は、ハニカム構造を有する触媒担体に担持させても良いし、筒体に装入してケージングさせても良い。   The denitration reactor 17 is provided with an SCR catalyst that selectively reduces and removes NOx contained in the exhaust gas discharged from the engine 12 and causing environmental pollution such as acid rain and photochemical smog. As the SCR catalyst, a desired catalyst such as a metal oxide catalyst such as alumina, zirconia, vanadia / titania or a zeolite catalyst can be used, and these catalysts may be combined. Further, the SCR catalyst may be supported on a catalyst carrier having a honeycomb structure, or may be charged in a cylinder and caged.

ＳＣＲ触媒を利用して排ガス中のＮＯx を窒素と水に分解して無害化する場合、その上流側で排ガス中にアンモニア等の還元剤を供給する必要があるが、アンモニア水を船内に貯蔵しておくことは危険を伴う。よって、本実施例ではノズル１９と接続されたタンクに還元剤前駆体として尿素を水溶液の状態で貯蔵しておき、運転時にノズル１９から尿素水１９ａを蒸発管１８内に噴射し、蒸発管１８の熱を利用して尿素を加水分解し、アンモニアガスを発生させるようにしている。   When NOx in exhaust gas is decomposed into nitrogen and water using an SCR catalyst to make it harmless, it is necessary to supply a reducing agent such as ammonia in the exhaust gas upstream, but ammonia water is stored in the ship. It is dangerous to keep. Therefore, in this embodiment, urea is stored as a reducing agent precursor in a tank connected to the nozzle 19 in the form of an aqueous solution, and during operation, the urea water 19a is injected from the nozzle 19 into the evaporation pipe 18, and the evaporation pipe 18 Urea is hydrolyzed using ammonia heat to generate ammonia gas.

図３は、第１実施例の蒸発管１８（内管）と排気通路１５（外管）の構成を示す拡大図である。第１実施例では、ノズル１９から噴霧した尿素水の加水分解反応が進行する時間を十分に確保するために、図３中、破線Ａ〜Ｂまでの区間を二重管構造による流速低減区間としている。   FIG. 3 is an enlarged view showing the configuration of the evaporation pipe 18 (inner pipe) and the exhaust passage 15 (outer pipe) of the first embodiment. In the first embodiment, in order to ensure sufficient time for the hydrolysis reaction of the urea water sprayed from the nozzle 19 to proceed sufficiently, the section from the broken lines A to B in FIG. Yes.

排気マニホールド１６によって集合された高温の排ガスは、排気通路１５内を流れて、破線Ａの位置で、蒸発管１８の内側を通過するものと、蒸発管１８の外側を通過するものとに分かれ、破線Ｂの位置で合流する。蒸発管１８の外側を通過する排ガスは、その時点では尿素水と混合されないが、蒸発管１８の内側を通過する排ガス中には加水分解を終えたアンモニアガスが含まれているので、破線Ｂの位置で合流した時にアンモニアガスと速やかに混合される。よって、脱硝反応器１７に導入される時点では、アンモニアガスは排ガス全体に行き渡った状態となっている。   The high-temperature exhaust gas collected by the exhaust manifold 16 flows into the exhaust passage 15 and is divided into one passing through the inside of the evaporation pipe 18 and one passing through the outside of the evaporation pipe 18 at the position of the broken line A. Merge at the position of the broken line B. The exhaust gas passing through the outside of the evaporation pipe 18 is not mixed with urea water at that time, but the exhaust gas passing through the inside of the evaporation pipe 18 contains ammonia gas that has been hydrolyzed. It quickly mixes with ammonia gas when it joins in place. Therefore, when introduced into the denitration reactor 17, the ammonia gas is in a state where it has spread throughout the exhaust gas.

なお、第１実施例では、蒸発管１８の外側を流れる排ガスを、旋回させずに真っ直ぐな流れに整流して、排ガスの流れを良好にするために、排気管１８の入口部１８ｂの外側の近傍にガイドベーン２０を設けている。   In the first embodiment, the exhaust gas flowing outside the evaporation pipe 18 is rectified into a straight flow without swirling so that the flow of the exhaust gas is good, so that the outside of the inlet 18b of the exhaust pipe 18 is improved. A guide vane 20 is provided in the vicinity.

図３に示すように、蒸発管１８の下流側の出口部１８ａはノズル状とし、入口部１８ｂよりも管径に絞りをかけている。また、このノズル状の出口部１８ａの開放端１８ａａが存在する位置（破線Ｂで示した位置）を少なくとも含むように、排気通路１５にベンチュリ１５ａを形成し、排気通路１５の管径にも絞りをかけている。   As shown in FIG. 3, the outlet portion 18a on the downstream side of the evaporation pipe 18 has a nozzle shape, and the tube diameter is narrower than that of the inlet portion 18b. Further, a venturi 15a is formed in the exhaust passage 15 so as to include at least a position (a position indicated by a broken line B) where the open end 18aa of the nozzle-shaped outlet portion 18a exists, and the diameter of the exhaust passage 15 is also reduced. It is over.

第１実施例では、排気通路１５に設けたベンチュリ１５ａの効果により、蒸発管１８のノズル状の出口部１８ａ付近の排ガスの圧力は、入口部１８ｂ付近の排ガスの圧力よりも低くなる。これにより、蒸発管１８内では、排ガスが滞留することなく、入口部１８ｂから出口部１８ａへと向かう安定した排ガスの流れができる。   In the first embodiment, due to the effect of the venturi 15 a provided in the exhaust passage 15, the pressure of the exhaust gas near the nozzle-shaped outlet portion 18 a of the evaporation pipe 18 becomes lower than the pressure of the exhaust gas near the inlet portion 18 b. Thereby, in the evaporation pipe 18, the flow of the stable exhaust gas which goes to the exit part 18a from the inlet part 18b can be performed, without waste gas staying.

図１と同様、破線Ａの位置における気体の流速をＶ0、排気通路１５において上流側の径をＤ、ベンチュリ１５ａの径をＤｒ、蒸発管１８において上流側の入口部１８ｂの径をｄ、ノズル状の出口部１８ａの径をｄｒとした場合、蒸発管１８の内側を通過する排ガスの速度Ｖは、Ｖ＝Ｖ0×{（ｄｒ×Ｄ）／（ｄ×Ｄｒ）}2の式で求められる。As in FIG. 1, the gas flow velocity at the position of the broken line A is V 0 , the upstream diameter in the exhaust passage 15 is D, the diameter of the venturi 15a is Dr, the diameter of the upstream inlet 18b in the evaporation pipe 18 is d, When the diameter of the nozzle-shaped outlet 18a is dr, the velocity V of the exhaust gas passing through the inside of the evaporation pipe 18 is expressed by the equation V = V 0 × {(dr × D) / (d × Dr)} 2 . Desired.

ここで、排気通路１５の絞りの程度（Ｄｒ／Ｄの値）や蒸発管１８の絞りの程度（ｄｒ／ｄの値）が不足しているか、又は、これらの絞りを全く設けない場合は、蒸発管１８の内側及び外側を通過する排ガスの速度が安定しない場合がある。逆に、Ｄｒ／Ｄやｄｒ／ｄの値を絞りすぎると、排気系の圧力損失が立ちすぎて、エンジンの効率または性能の低下を招くおそれがある。よって、排気通路１５と蒸発管１８の絞りの程度は、これらの管のサイズや形状、目標とする排ガスの流速Ｖの値に応じて調整する。   Here, when the degree of restriction of the exhaust passage 15 (Dr / D value), the degree of restriction of the evaporation pipe 18 (value of dr / d) is insufficient, or when these restrictions are not provided at all, The speed of the exhaust gas passing through the inside and outside of the evaporation pipe 18 may not be stable. On the other hand, if the values of Dr / D and dr / d are too narrow, the pressure loss of the exhaust system will be too high and the engine efficiency or performance may be reduced. Therefore, the degree of restriction of the exhaust passage 15 and the evaporation pipe 18 is adjusted according to the size and shape of these pipes and the target value of the flow velocity V of the exhaust gas.

図４は、本発明の排ガス浄化装置の第２実施例の構成を示した図である。この第２実施例の排ガス浄化装置１１が前述の第１実施例と異なる点は、蒸発管１８の入口部１８ｂと出口部１８ａの径の長さは同じとし、蒸発管１８（内管）に絞りを設けていない点と、蒸発管１８の内部にノズル１９から噴霧された尿素水１９ａ（還元剤、還元剤前駆体の双方または何れか一方を含む水溶液）の加水分解を促進するための尿素加水分解触媒２３を設けた点である。この尿素加水分解触媒２３は、例えば、酸化チタン（ＴｉＯ2）の担体に酸化タングステン（ＷＯ３）を添加した構造のものを使用することができる。FIG. 4 is a diagram showing the configuration of the second embodiment of the exhaust gas purifying apparatus of the present invention. The difference between the exhaust gas purifying apparatus 11 of the second embodiment and the first embodiment is that the diameter of the inlet portion 18b and the outlet portion 18a of the evaporation pipe 18 are the same, and the evaporation pipe 18 (inner pipe) is connected. Urea for accelerating the hydrolysis of urea water 19a (an aqueous solution containing either or both of a reducing agent and a reducing agent precursor) sprayed from the nozzle 19 inside the evaporation pipe 18 without a restriction. This is a point where a hydrolysis catalyst 23 is provided. As the urea hydrolysis catalyst 23, for example, a catalyst having a structure in which tungsten oxide (WO3) is added to a support of titanium oxide (TiO 2 ) can be used.

図５は、第２実施例の蒸発管１８（内管）と排気通路１５（外管）の構成を示す拡大図である。第２実施例では、ノズル１９から噴霧した尿素水の加水分解反応が進行する時間を十分に確保するために、図５中、破線Ａ〜Ｂまでの区間を二重管構造による流速低減区間としているが、出口部１８ａに絞りは設けていない。一方で、図５に示すように、蒸発管１８の内部で出口部１８ａの近傍に尿素加水分解触媒２３を配置している。このように出口部１８ａに尿素加水分解触媒２３を配置すると、この尿素加水分解触媒２３を排ガスが通過するときの圧力損失により、蒸発管１８内を流れる排ガス流量が減少する。これにより、第２実施例の構成においても、蒸発管１８内を流れる排ガスの流速を遅くすることができる。加えて、第２実施例では、この尿素加水分解触媒２３の作用により尿素の加水分解が促進されるので、流速低減区間内でアンモニアへの加水分解を完結することができる。   FIG. 5 is an enlarged view showing the configuration of the evaporation pipe 18 (inner pipe) and the exhaust passage 15 (outer pipe) of the second embodiment. In 2nd Example, in order to fully ensure the time for the hydrolysis reaction of the urea water sprayed from the nozzle 19 to advance, the area to the broken line AB in FIG. 5 is made into the flow velocity reduction area by a double pipe structure. However, the outlet 18a is not provided with a throttle. On the other hand, as shown in FIG. 5, a urea hydrolysis catalyst 23 is arranged in the vicinity of the outlet 18 a inside the evaporation pipe 18. When the urea hydrolysis catalyst 23 is arranged at the outlet 18a in this way, the flow rate of exhaust gas flowing through the evaporation pipe 18 is reduced due to pressure loss when the exhaust gas passes through the urea hydrolysis catalyst 23. Thereby, also in the structure of 2nd Example, the flow velocity of the waste gas which flows through the inside of the evaporation pipe 18 can be made slow. In addition, in the second embodiment, urea hydrolysis is promoted by the action of the urea hydrolysis catalyst 23, so that hydrolysis to ammonia can be completed within the flow rate reduction section.

本発明では、蒸発管１８（内管）を通過する排ガスは流速が遅いので、その排ガスに含まれる尿素の速度も遅くなる。よって、尿素が尿素加水分解触媒２３を通過するまでの時間が長くなり、尿素と尿素加水分解触媒２３が接触する頻度が高くなるので、少ない触媒量でも所要の加水分解率が得られる。また、蒸発管１８内を流れる排ガス流量は少ないので、そこに所要の量の尿素を投入することにより、排ガス中の尿素の濃度が高くなる。これにより、尿素と尿素加水分解触媒２３が接触する頻度が高くなるので、少ない触媒量でも所要の加水分解率が得られる。   In the present invention, since the exhaust gas passing through the evaporation pipe 18 (inner pipe) has a low flow velocity, the speed of urea contained in the exhaust gas is also reduced. Therefore, the time until urea passes through the urea hydrolysis catalyst 23 becomes longer, and the frequency of contact between urea and the urea hydrolysis catalyst 23 increases. Therefore, the required hydrolysis rate can be obtained even with a small amount of catalyst. In addition, since the flow rate of the exhaust gas flowing through the evaporation pipe 18 is small, the concentration of urea in the exhaust gas is increased by introducing a required amount of urea therein. Thereby, since the frequency with which urea and the urea hydrolysis catalyst 23 come into contact increases, a required hydrolysis rate can be obtained even with a small amount of catalyst.

また、図９に示すような、従来の蒸発管１０７では、尿素水の噴霧状態が良くないと、尿素水の一部が蒸発管１０７の内面に付着し、その付着部分が冷温になって尿素に十分な熱が加わらないため、アンモニアではなく、シアヌル酸やビュレット、メラミン、その他の尿素由来の化合物が生成され、それらの堆積物が蒸発管１０７の内面に付着し、この堆積物が排ガスの流れを妨げるという問題があった。これに対し、本発明では、上記のとおり二重管構造を採用することにより、蒸発管１８の内面に尿素水が付着した場合に、蒸発管１８内を流れる排ガスの熱のみならず、蒸発管１８の外側を流れる排ガスからも熱が加わるので、尿素水が付着した部分が冷温になり難く、尿素由来の上記堆積物が生成され難いという利点がある。   Further, in the conventional evaporation pipe 107 as shown in FIG. 9, if the spray state of the urea water is not good, a part of the urea water adheres to the inner surface of the evaporation pipe 107, and the attached part becomes cold and the urea becomes cold. As a result, cyanuric acid, burette, melamine, and other urea-derived compounds are produced instead of ammonia, and these deposits adhere to the inner surface of the evaporation tube 107, and these deposits form exhaust gas. There was a problem of obstructing the flow. On the other hand, in the present invention, by adopting the double pipe structure as described above, when urea water adheres to the inner surface of the evaporation pipe 18, not only the heat of the exhaust gas flowing in the evaporation pipe 18 but also the evaporation pipe Since heat is also applied from the exhaust gas flowing outside 18, there is an advantage that the portion to which the urea water adheres is unlikely to cool, and the urea-derived deposit is difficult to be generated.

図６は、本発明の排ガス浄化装置の第３実施例の構成を示した図である。５１は、本発明を４気筒の舶用ディーゼルエンジンに適用した排ガス浄化装置であり、エンジン５２の各シリンダヘッドに設けられた排気ポート５２ａに夫々接続された排気連絡管５３から排出された排ガスを集合し、ターボチャージャー５４のタービン５４ａの上流側の排気通路５５に導く排気マニホールド５６の内部に、長手方向両端が排気マニホールド５６内に開放された蒸発管５８と脱硝反応器５７が連続配置されている。そして、蒸発管５８内を通過する排ガスに対して還元剤、還元剤前駆体の双方または何れか一方を含む水溶液５９ａを噴霧可能なノズル５９が設けられている。   FIG. 6 is a diagram showing the configuration of a third embodiment of the exhaust gas purifying apparatus of the present invention. Reference numeral 51 denotes an exhaust gas purifying apparatus in which the present invention is applied to a four-cylinder marine diesel engine, and collects exhaust gases discharged from exhaust communication pipes 53 respectively connected to exhaust ports 52a provided in each cylinder head of the engine 52. An evaporation pipe 58 and a denitration reactor 57 having both ends in the longitudinal direction opened into the exhaust manifold 56 are continuously arranged inside the exhaust manifold 56 leading to the exhaust passage 55 upstream of the turbine 54 a of the turbocharger 54. . A nozzle 59 is provided that can spray an aqueous solution 59a containing either or both of the reducing agent and the reducing agent precursor to the exhaust gas passing through the evaporation pipe 58.

蒸発管５８の出口部５８ａの形状はノズル状であり、入口部５８ｂの径よりも小さくしている。また、蒸発管５８の出口部５８ａの開放端５８ａａが存在する位置を含むように排気マニホールド５６にベンチュリ５６ａを形成している。なお、５４ｂは、給気通路６１から給気された空気を圧縮するターボチャージャー５４のコンプレッサを示している。また、６２は、コンプレッサ５４ｂによって圧縮された空気を、給気連絡管を介してエンジン５２の各シリンダの給気ポートに分配する給気マニホールドを示している。   The shape of the outlet portion 58a of the evaporation pipe 58 is a nozzle shape, which is smaller than the diameter of the inlet portion 58b. Further, a venturi 56a is formed in the exhaust manifold 56 so as to include a position where the open end 58aa of the outlet portion 58a of the evaporation pipe 58 exists. Reference numeral 54 b denotes a compressor of the turbocharger 54 that compresses the air supplied from the supply passage 61. Reference numeral 62 denotes an air supply manifold that distributes the air compressed by the compressor 54b to the air supply ports of the cylinders of the engine 52 via the air supply communication pipe.

つまり、第３実施例は、排気マニホールド５６が図１の外管２に、蒸発管５８が図１の内管３に相当するものであり、蒸発管５８を排気マニホールド５６の内部に組み込んだ点が、第１実施例と相違している。   That is, in the third embodiment, the exhaust manifold 56 corresponds to the outer pipe 2 in FIG. 1 and the evaporation pipe 58 corresponds to the inner pipe 3 in FIG. 1, and the evaporation pipe 58 is incorporated in the exhaust manifold 56. However, this is different from the first embodiment.

よって、第３実施例では、排気マニホールド５６の内部に、蒸発管５８及び脱硝反応器５７の全部が組み込まれているので、管径のサイズが大きい蒸発管が排気マニホールドと併設されていた従来の装置と比較すると、装置サイズが格段にコンパクトになる。また、一般に、ターボチャージャーを備えたエンジンにおいては、急な加速を行うときにエンジン出力の増大要求に対し給気の遅れが生じるなど制御遅れが生じる場合があるが、第３実施例の構成では、タービン５４ａに至る排気の経路を短くすることができるので、排気制御も容易となる。   Therefore, in the third embodiment, since all of the evaporation pipe 58 and the denitration reactor 57 are incorporated in the exhaust manifold 56, an evaporation pipe having a large pipe diameter is provided together with the exhaust manifold. Compared with the device, the device size is much more compact. Further, in general, in an engine equipped with a turbocharger, there may be a control delay such as a delay in supply air in response to a request for an increase in engine output when sudden acceleration is performed. In the configuration of the third embodiment, Since the exhaust path to the turbine 54a can be shortened, exhaust control is also facilitated.

図７は、本発明の排ガス浄化装置の第４実施例の構成を示した図である。この第４実施例の排ガス浄化装置５１が前述の第３実施例と異なる点は、蒸発管５８の入口部５８ｂと出口部５８ａの径の長さは同じとし、蒸発管５８（内管）に絞りを設けていない点と、蒸発管５８の内部にノズル５９から噴霧された尿素水５９ａ（還元剤、還元剤前駆体の双方または何れか一方を含む水溶液）の加水分解を促進するための尿素加水分解触媒６３を設けた点である。この尿素加水分解触媒６３は、前述の第２実施例と同様、例えば、酸化チタン（ＴｉＯ2）の担体に酸化タングステン（ＷＯ３）を添加した構造のものを使用することができる。FIG. 7 is a view showing the configuration of a fourth embodiment of the exhaust gas purifying apparatus of the present invention. The difference between the exhaust gas purifying apparatus 51 of the fourth embodiment and the third embodiment is that the diameters of the inlet 58b and outlet 58a of the evaporation pipe 58 are the same, and the evaporation pipe 58 (inner pipe) Urea for accelerating hydrolysis of urea water 59a (an aqueous solution containing either or both of a reducing agent and a reducing agent precursor) sprayed from a nozzle 59 inside the evaporation pipe 58 without a restriction. This is the point that a hydrolysis catalyst 63 is provided. The urea hydrolysis catalyst 63, similarly to the second embodiment described above, for example, can be used as the added structure carrier tungsten oxide (WO3) of titanium oxide (TiO 2).

第４実施例では、蒸発管５８の内部で出口部５８ａの近傍に尿素加水分解触媒６３を配置し、この尿素加水分解触媒６３の作用により尿素の加水分解が促進されるので、流速低減区間内でアンモニアへの加水分解を完結することができる。   In the fourth embodiment, the urea hydrolysis catalyst 63 is disposed in the vicinity of the outlet 58a inside the evaporation pipe 58, and the urea hydrolysis is promoted by the action of the urea hydrolysis catalyst 63. Can complete the hydrolysis to ammonia.

本発明は、前記の実施例に限るものではなく、各請求項に記載の技術的思想の範囲内において、適宜実施の形態を変更しても良いことは言うまでもない。   The present invention is not limited to the above-described embodiments, and it goes without saying that the embodiments may be appropriately changed within the scope of the technical idea described in each claim.

例えば、前記の実施例では、蒸発管１８内の排ガスにノズル１９から還元剤前駆体として尿素水１９ａを噴霧する構成を開示したが、還元剤前駆体の成分はこれに限らない。例えば、高濃度の尿素と低濃度のアンモニアの混合水溶液を使用しても良い。   For example, in the above-described embodiment, the configuration in which the urea water 19a is sprayed as the reducing agent precursor from the nozzle 19 to the exhaust gas in the evaporation pipe 18 is disclosed, but the components of the reducing agent precursor are not limited thereto. For example, a mixed aqueous solution of high concentration urea and low concentration ammonia may be used.

また、前記の実施例では、蒸発管１８の入口部１８ｂの近傍にノズル１９を設ける例を開示したが、ノズル１９を設ける位置はこれに限らず、例えば蒸発管１８の中央に設けても良い。   Moreover, although the example which provides the nozzle 19 in the vicinity of the inlet part 18b of the evaporation pipe | tube 18 was disclosed in the said Example, the position which provides the nozzle 19 is not restricted to this, For example, you may provide in the center of the evaporation pipe | tube 18. .

また、第２実施例では、図５に示すように、蒸発管１８の内部に尿素加水分解触媒２３を配置する場合において、蒸発管１８の出口部１８ａに絞りは設けない例を開示したが、第２実施例の構成はこれに限らない。例えば、図８に示す変形例ように、蒸発管１８の内部に尿素加水分解触媒２３を配置する場合においても、蒸発管１８の出口部１８ａに絞りを設けても良い。   Further, in the second embodiment, as shown in FIG. 5, in the case where the urea hydrolysis catalyst 23 is arranged inside the evaporation pipe 18, an example in which no restriction is provided at the outlet portion 18a of the evaporation pipe 18 is disclosed. The configuration of the second embodiment is not limited to this. For example, as in the modification shown in FIG. 8, even when the urea hydrolysis catalyst 23 is disposed inside the evaporation pipe 18, a throttle may be provided at the outlet portion 18 a of the evaporation pipe 18.

蒸発管１８の出口部１８ａに絞りを設けない図５の構成でも、尿素加水分解触媒２３を配置したことによる圧力損失により、排ガスの流速をある程度低減することは可能であるが、排ガスの流速を所望の速度に細かく調整することは困難である。これに対し、図８の構成のように、蒸発管１８の出口部１８ａに絞りを設ける場合は、絞りの程度を最適に設計することにより排ガスの流速の調整が容易に行える。   Even in the configuration of FIG. 5 in which the outlet 18a of the evaporation pipe 18 is not provided with a throttle, the flow rate of the exhaust gas can be reduced to some extent due to the pressure loss due to the urea hydrolysis catalyst 23 being arranged. Fine adjustment to the desired speed is difficult. On the other hand, when the throttle is provided at the outlet 18a of the evaporation pipe 18 as in the configuration of FIG. 8, the flow rate of the exhaust gas can be easily adjusted by designing the degree of the throttle optimally.

このように、尿素加水分解触媒２３と出口部１８ａの絞りを併用した場合は、排ガスの流速を所望の速度に低減し易く、かつ、触媒の作用により尿素の加水分解を促進することができる。   Thus, when the urea hydrolysis catalyst 23 and the throttle of the outlet portion 18a are used in combination, the flow rate of the exhaust gas can be easily reduced to a desired speed, and the hydrolysis of urea can be promoted by the action of the catalyst.

また、第３実施例では、蒸発管５８の内部にノズル５９のみを設ける例を開示したが、ノズル５９の下流側であって、かつ、蒸発管５８の内部に、蒸発管５８内の排ガスの流れを整えるために整流器を設けても良い。また、尿素水５９ａが加水分解されて生じたアンモニアガスと排ガスが蒸発管５８内で十分に混合されるように、蒸発管５８の内部にスタティックミキサーを設けても良い。   Further, in the third embodiment, an example in which only the nozzle 59 is provided inside the evaporation pipe 58 is disclosed, but the exhaust gas in the evaporation pipe 58 is disposed downstream of the nozzle 59 and inside the evaporation pipe 58. A rectifier may be provided to regulate the flow. Further, a static mixer may be provided inside the evaporation pipe 58 so that ammonia gas and exhaust gas generated by hydrolysis of the urea water 59a are sufficiently mixed in the evaporation pipe 58.

１１ 排ガス浄化装置
１２ エンジン
１２ａ 排気ポート
１３ 排気連絡管
１４ ターボチャージャー
１４ａ タービン
１５ 排気通路
１５ａ ベンチュリ
１６ 排気マニホールド
１７ 脱硝反応器
１８ 蒸発管
１８ａ 出口部
１８ｂ 入口部
１９ ノズル
１９ａ 尿素水DESCRIPTION OF SYMBOLS 11 Exhaust gas purification device 12 Engine 12a Exhaust port 13 Exhaust communication pipe 14 Turbocharger 14a Turbine 15 Exhaust passage 15a Venturi 16 Exhaust manifold 17 Denitration reactor 18 Evaporating pipe 18a Outlet part 18b Inlet part 19 Nozzle 19a Urea water

Claims (4)

エンジンの排気ポートに接続された排気連絡管から排出された排ガスを集合し、排気通路に導く排気マニホールドと、前記排気通路に設けられた脱硝反応器とを備え、
前記脱硝反応器の上流側であって、かつ、前記排気通路の内部に、長手方向両端が開放された蒸発管を設けると共に、前記蒸発管内を通過する排ガスに対して還元剤、還元剤前駆体の双方または何れか一方を含む水溶液を噴霧可能なノズルを設け、
前記蒸発管の出口部の径を入口部の径よりも小さくすると共に、前記蒸発管の出口部の開放端が存在する位置を含むように前記排気通路にベンチュリを形成したことを特徴とする排ガス浄化装置。 An exhaust manifold that collects exhaust gas discharged from an exhaust communication pipe connected to an exhaust port of the engine and guides the exhaust gas to an exhaust passage; and a denitration reactor provided in the exhaust passage;
An evaporation pipe that is upstream of the denitration reactor and that is open at both ends in the longitudinal direction is provided inside the exhaust passage, and a reducing agent and a reducing agent precursor for the exhaust gas that passes through the evaporation pipe. both or aqueous solution containing one provided sprayable nozzles,
The exhaust gas is characterized in that a venturi is formed in the exhaust passage so as to include a position where an opening end of the outlet portion of the evaporation pipe is present while making the diameter of the outlet portion of the evaporation pipe smaller than the diameter of the inlet portion. Purification equipment. 前記蒸発管の内部に、前記ノズルから噴霧された還元剤、還元剤前駆体の双方または何れか一方を含む水溶液の加水分解を促進するための尿素加水分解触媒を設けたことを特徴とする請求項１に記載の排ガス浄化装置。   The urea hydrolysis catalyst for accelerating the hydrolysis of the aqueous solution containing either or both of the reducing agent and the reducing agent precursor sprayed from the nozzle is provided inside the evaporation pipe. Item 2. An exhaust gas purifying apparatus according to Item 1. エンジンの排気ポートに接続された排気連絡管から排出された排ガスを集合し、排気通路に導く排気マニホールドの内部に、長手方向両端が開放された蒸発管と脱硝反応器を連続配置すると共に、前記蒸発管内を通過する排ガスに対して還元剤、還元剤前駆体の双方または何れか一方を含む水溶液を噴霧可能なノズルを設け、
前記蒸発管の出口部の径を入口部の径よりも小さくすると共に、前記蒸発管の出口部の開放端が存在する位置を含むように前記排気マニホールドにベンチュリを形成したことを特徴とする排ガス浄化装置。 An exhaust pipe that collects exhaust gas discharged from the exhaust communication pipe connected to the exhaust port of the engine and leads to the exhaust passage is continuously arranged with an evaporation pipe and a denitration reactor that are open at both ends in the longitudinal direction. A nozzle capable of spraying an aqueous solution containing either or both of a reducing agent and a reducing agent precursor to exhaust gas passing through the evaporation pipe ;
An exhaust gas characterized in that a venturi is formed in the exhaust manifold so as to include a position where an opening end of the outlet portion of the evaporation pipe exists while making the diameter of the outlet portion of the evaporation pipe smaller than the diameter of the inlet portion. Purification equipment. 前記蒸発管の内部に、前記ノズルから噴霧された還元剤、還元剤前駆体の双方または何れか一方を含む水溶液の加水分解を促進するための尿素加水分解触媒を設けたことを特徴とする請求項３に記載の排ガス浄化装置。 The urea hydrolysis catalyst for accelerating the hydrolysis of the aqueous solution containing either or both of the reducing agent and the reducing agent precursor sprayed from the nozzle is provided inside the evaporation pipe. Item 6. The exhaust gas purifying apparatus according to Item 3 .
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KR20140129366A (en) 2014-11-06
KR101619098B1 (en) 2016-05-10
TWI576507B (en) 2017-04-01
TW201339409A (en) 2013-10-01
JPWO2013136614A1 (en) 2015-08-03
CN104136727B (en) 2016-08-24
WO2013136614A1 (en) 2013-09-19

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