JP2002349248A - Nitrogen oxide in diesel engine exhaust gas removing method and device - Google Patents
Nitrogen oxide in diesel engine exhaust gas removing method and deviceInfo
- Publication number
- JP2002349248A JP2002349248A JP2001150614A JP2001150614A JP2002349248A JP 2002349248 A JP2002349248 A JP 2002349248A JP 2001150614 A JP2001150614 A JP 2001150614A JP 2001150614 A JP2001150614 A JP 2001150614A JP 2002349248 A JP2002349248 A JP 2002349248A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- catalyst
- oxidation catalyst
- oxidation
- reduction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B3/00—Engines characterised by air compression and subsequent fuel addition
- F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
-
- 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
Landscapes
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、微量の一酸化窒素
と高濃度の酸素、さらに硫黄酸化物をも含有するディー
ゼルエンジン排ガスの脱硝処理に適用される窒素酸化物
除去方法及び装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for removing nitrogen oxides applied to a denitration treatment of a diesel engine exhaust gas containing a trace amount of nitric oxide, a high concentration of oxygen and a sulfur oxide. is there.
【０００２】[0002]
【従来の技術】自動車、船舶など近代の輸送機関に用い
られてきたディーゼルエンジンから排出される排ガスに
は、多量の有害な窒素酸化物（ＮＯx）が含有されてお
り、地球環境破壊原因の一つであると考えられているた
め、排ガス中から窒素酸化物を除去することが望まれて
いる。しかし、ディーゼルエンジン排ガスは低温、かつ
高濃度の酸素、硫黄酸化物（ＳＯx）をも含有するた
め、通常のガソリンエンジン排ガス用処理触媒の適用が
難しいとされている。ディーゼルエンジン排ガス中の窒
素酸化物除去方法としては、例えば、以下のような従来
技術が知られている。2. Description of the Related Art Exhaust gas emitted from diesel engines used in modern transportation such as automobiles and ships contains a large amount of harmful nitrogen oxides (NOx), which is one of the causes of global environmental destruction. Therefore, it is desired to remove nitrogen oxides from exhaust gas. However, since diesel engine exhaust gas also contains low-temperature and high-concentration oxygen and sulfur oxides (SOx), it is difficult to apply a normal gasoline engine exhaust gas treatment catalyst. As a method for removing nitrogen oxides from diesel engine exhaust gas, for example, the following conventional techniques are known.
【０００３】特開平８−１１７５５８号公報には、二酸
化窒素を生成する方法として、還元性物質、窒素酸化物
及び過剰の酸素が存在する酸化雰囲気の排気ガス中の還
元性物質を、還元性物質酸化触媒により酸化し、次い
で、排気ガス中の窒素酸化物を窒素酸化物酸化触媒によ
り二酸化窒素に変換する方法が記載されている。この方
法では、排気ガス中の炭化水素等の還元性物質をあらか
じめ除去することにより、Ｐｔ等の窒素酸化物酸化触媒
が効率よくＮＯをＮＯ2に酸化することができ、生成し
たＮＯ2は反応性が高く、炭化水素等の還元剤による還
元や活性炭／アルカリを含む吸収剤による吸収等での浄
化処理がＮＯよりも容易になるとされている。Japanese Patent Application Laid-Open No. Hei 8-117558 discloses a method for producing nitrogen dioxide, which comprises reducing a reducing substance in exhaust gas in an oxidizing atmosphere containing a reducing substance, nitrogen oxides and excess oxygen. It describes a method of oxidizing with an oxidation catalyst and then converting nitrogen oxides in the exhaust gas to nitrogen dioxide with a nitrogen oxide oxidation catalyst. According to this method, a nitrogen oxide oxidation catalyst such as Pt can efficiently oxidize NO to NO 2 by removing a reducing substance such as hydrocarbon in exhaust gas in advance, and the generated NO 2 It is said that the purification process is easier than NO by reduction with a reducing agent such as a hydrocarbon or absorption by an absorbent containing activated carbon / alkali.
【０００４】また、特開平８−２６６８６８号公報に
は、燃焼排ガス中の窒素酸化物を炭化水素等を還元剤と
して窒素に還元する脱硝方法において、排ガスを酸化触
媒と接触させて排ガス中の一酸化窒素を二酸化窒素に酸
化し、ついで、排ガス中に還元剤を添加するとともに、
排ガスを脱硝触媒と接触させて窒素酸化物を窒素に還元
する方法及び装置が記載されている。この技術では、酸
化触媒として、Ａｌ2Ｏ3、ＳｉＯ2、ＺｒＯ2、Ｔｉ
Ｏ2、ゼオライトからなる群より選ばれた少なくとも１
種の担体にＰｔ、Ｐｄ、Ｒｕ、Ｃｏ、Ｃｕ、Ｍｎからな
る群より選ばれた少なくとも１種の金属の化合物を含有
させたものが用いられ、脱硝触媒として、Ａｌ 2Ｏ3、Ｓ
ｉＯ2、ＺｒＯ2、ＴｉＯ2、ゼオライトからなる群より
選ばれた少なくとも１種の担体にＮｉ、Ｚｎ、Ｍｎ、Ｉ
ｎ、Ａｇからなる群より選ばれた少なくとも１種の金属
の化合物を含有させたものが用いられる。また、複数層
設けた脱硝触媒間に熱交換器を設けて、反応熱を回収す
るとともに排ガス温度を脱硝に適する温度範囲内に制御
すること、さらに、排ガス流れ方向に対して２箇所以上
で還元剤を添加することにより、還元剤の効率の低下、
炭素の析出等の問題を解決することができるとされてい
る。Further, Japanese Patent Application Laid-Open No. 8-266868 discloses
Converts nitrogen oxides in flue gas into hydrocarbons and other reducing agents.
Exhaust gas in the denitration method of reducing
Nitric oxide in exhaust gas to nitrogen dioxide
Then, while adding a reducing agent to the exhaust gas,
Contacting the exhaust gas with a denitration catalyst to reduce nitrogen oxides to nitrogen
A method and apparatus are described. In this technology, acid
Al conversion catalystTwoOThree, SiOTwo, ZrOTwo, Ti
OTwo, At least one selected from the group consisting of zeolites
Pt, Pd, Ru, Co, Cu, Mn
Contains at least one metal compound selected from the group consisting of
The denitration catalyst is used as the denitration catalyst. TwoOThree, S
iOTwo, ZrOTwo, TiOTwoFrom the group consisting of zeolites
Ni, Zn, Mn, I
at least one metal selected from the group consisting of n and Ag
A compound containing the compound is used. Also multiple layers
Install a heat exchanger between the provided denitration catalysts to recover reaction heat
Control the exhaust gas temperature within a temperature range suitable for denitration
And more than two places in the exhaust gas flow direction
By adding the reducing agent in the above, the efficiency of the reducing agent decreases,
It is said that it can solve problems such as carbon deposition.
You.
【０００５】[0005]
【発明が解決しようとする課題】しかし、上記の特開平
８−１１７５５８号公報の技術では、Ｐｄ、Ｐｔ、Ｒｈ
等の貴金属を成分として含む窒素酸化物酸化触媒に第２
成分を添加することは記載されておらず、しかも、実際
のディーゼルエンジン排ガス中に含まれているＳＯxに
対する耐久性については、全く言及されていない。ま
た、地球温暖化防止の観点から、温室効果ガスとしてそ
の排出が懸念されている亜酸化窒素（Ｎ2Ｏ）は、脱硝
反応に付随して生じやすいが、それらについては全く記
載されていない。さらに、これら全ての方法を実現する
手段についても記載がない。また、酸化触媒から出た二
酸化窒素等を含む排ガスに炭化水素等の還元剤を添加し
て還元触媒に導入する方法及び装置についても全く開示
されていない。However, in the technique disclosed in Japanese Patent Application Laid-Open No. Hei 8-117558, Pd, Pt, Rh
The second is a nitrogen oxide oxidation catalyst containing a noble metal such as
No addition of the component is described, and no mention is made of the durability against SOx contained in actual diesel engine exhaust gas. In addition, from the viewpoint of preventing global warming, nitrous oxide (N 2 O), whose emission is concerned about as a greenhouse gas, is likely to be generated accompanying the denitration reaction, but is not described at all. Further, there is no description on means for realizing all these methods. Also, there is no disclosure of a method and apparatus for adding a reducing agent such as a hydrocarbon to exhaust gas containing nitrogen dioxide or the like emitted from an oxidation catalyst and introducing the reducing agent into the reduction catalyst.
【０００６】また、上記の特開平８−２６６８６８号公
報の技術では、Ｐｔ、Ｐｄ、Ｒｕ、Ｃｏ、Ｃｕ、Ｍｎか
らなる群より選ばれた少なくとも１種の金属を含む酸化
触媒に第２成分を添加することは記載されておらず、し
かも、実際のディーゼルエンジン排ガス中に含まれてい
るＳＯxに対する耐久性については、全く言及されてい
ない。また、酸化触媒と還元触媒（脱硝触媒）の各々の
性能を最大限に引き出す温度域での反応操作について、
酸化触媒の方が還元触媒よりも高くなるような異なる温
度域として操作することは記載されていない。また、地
球温暖化防止の観点から、温室効果ガスとしてその排出
が懸念されている亜酸化窒素（Ｎ2Ｏ）は、脱硝反応に
付随して生じやすいが、それらについては全く記載され
ていない。また、外部熱源を利用した熱交換器による温
度保持方法では、エネルギーコスト的に不利であると考
えられる。According to the technique disclosed in Japanese Patent Application Laid-Open No. 8-266868, the second component is added to an oxidation catalyst containing at least one metal selected from the group consisting of Pt, Pd, Ru, Co, Cu, and Mn. No addition is described, and no mention is made of the durability against SOx contained in actual diesel engine exhaust gas. In addition, regarding the reaction operation in the temperature range that maximizes the performance of each of the oxidation catalyst and the reduction catalyst (denitration catalyst),
It does not describe operating in a different temperature range where the oxidation catalyst is higher than the reduction catalyst. In addition, from the viewpoint of preventing global warming, nitrous oxide (N 2 O), whose emission is concerned about as a greenhouse gas, is likely to be generated accompanying the denitration reaction, but is not described at all. Further, it is considered that the method of maintaining the temperature by the heat exchanger using the external heat source is disadvantageous in energy cost.
【０００７】本発明は上記の諸点に鑑みなされたもの
で、本発明の目的は、微量の一酸化窒素と高濃度の酸
素、さらに硫黄酸化物を含有するディーゼルエンジン排
ガスを、前段の酸化触媒にて一酸化窒素を二酸化窒素に
酸化した後、前段と後段の間から炭化水素還元剤を導入
し、後段の還元触媒にて窒素酸化物を窒素ガスへ効率的
に転換することを組み合わせ、前段の酸化触媒にＳＯx
被毒を低く抑えるための第２成分を添着させ、なおか
つ、酸化触媒及び還元触媒の各々の操作温度域を各々の
触媒が最高活性を示す異なる温度域とすることにより、
全体としての脱硝活性を大幅に向上させるだけでなく、
全体の脱硝性能の硫黄被毒耐性を高めることができ、し
かも、一般の窒素酸化物除去反応に付随して生じやすい
亜酸化窒素の発生がほとんどなく、かつ、きわめて少な
い炭化水素還元剤の供給量で効率的に窒素ガスへの転換
が行えるディーゼルエンジン排ガス中の窒素酸化物除去
方法及び装置を提供することにある。[0007] The present invention has been made in view of the above points, and an object of the present invention is to convert a diesel engine exhaust gas containing a trace amount of nitric oxide, a high concentration of oxygen, and a sulfur oxide into a preceding oxidation catalyst. After oxidizing nitrogen monoxide to nitrogen dioxide by introducing a hydrocarbon reducing agent between the former stage and the latter stage, and combining the efficient conversion of nitrogen oxides into nitrogen gas with the latter reducing catalyst, SOx for oxidation catalyst
By adhering the second component for suppressing poisoning, and by setting the operating temperature range of each of the oxidation catalyst and the reduction catalyst to a different temperature range in which each catalyst exhibits the highest activity,
Not only greatly improves the overall denitration activity,
Sulfur poisoning resistance of the entire denitration performance can be increased, and there is almost no generation of nitrous oxide, which is likely to occur with general nitrogen oxide removal reaction, and the supply amount of hydrocarbon reducing agent is extremely small. It is an object of the present invention to provide a method and an apparatus for removing nitrogen oxides from exhaust gas of a diesel engine, which can efficiently convert the nitrogen gas into nitrogen gas.
【０００８】また、本発明の目的は、ディーゼルエンジ
ン排ガスを前段の酸化触媒にて一酸化窒素を二酸化窒素
に酸化した後、前段と後段の間から炭化水素還元剤を導
入し、後段の還元触媒にて窒素酸化物を窒素ガスへ効率
的に転換することを組み合わせた方法及び装置におい
て、還元触媒で昇温された高温の排ガスの熱を利用して
酸化触媒の加熱を行ったり、還元触媒に導入する排ガス
の温度を酸化触媒の出口温度よりは低温にするために、
酸化触媒から出た高温の排ガスを入口ガスと熱交換して
冷却を行うことにより、外部熱源をほとんど又は全く利
用することなく、酸化触媒及び還元触媒の各々の操作温
度域を各々の触媒が最高活性を示す異なる温度域にする
ことができるディーゼルエンジン排ガス中の窒素酸化物
除去方法及び装置を提供することにある。It is another object of the present invention to oxidize nitrogen monoxide to nitrogen dioxide by using a first stage oxidation catalyst of diesel engine exhaust gas, and then introduce a hydrocarbon reducing agent between the first and second stages to form a second stage reduction catalyst. In a method and apparatus that combines the efficient conversion of nitrogen oxides into nitrogen gas by using the heat of the high temperature exhaust gas heated by the reduction catalyst, the oxidation catalyst is heated, In order to make the temperature of the exhaust gas to be introduced lower than the outlet temperature of the oxidation catalyst,
By cooling the high-temperature exhaust gas discharged from the oxidation catalyst by exchanging heat with the inlet gas, each of the catalysts can reach the maximum operating temperature range of the oxidation catalyst and the reduction catalyst with little or no external heat source. It is an object of the present invention to provide a method and an apparatus for removing nitrogen oxides from exhaust gas of a diesel engine which can be set in different temperature ranges showing activity.
【０００９】[0009]
【課題を解決するための手段】上記の目的を達成するた
めに、本発明のディーゼルエンジン排ガス中の窒素酸化
物除去方法は、ディーゼルエンジン排ガスを前段の酸化
触媒と接触させて排ガス中の一酸化窒素を二酸化窒素に
酸化した後、この排ガスに後段の還元触媒の上流側で炭
化水素還元剤を添加し、ついで、排ガスを後段の還元触
媒と接触させて、前段で生成した二酸化窒素を含む窒素
酸化物を窒素ガスに転換する窒素酸化物除去方法であっ
て、前段の酸化触媒に硫黄被毒による触媒性能低下を抑
える第２成分を添着させることにより、全体の脱硝性能
の硫黄被毒耐性を高めるとともに、酸化触媒及び還元触
媒における各々の反応温度を、酸化触媒の方が還元触媒
よりも高くなるような各々の触媒が最高活性を示す異な
る温度域として操作するように構成されている。In order to achieve the above-mentioned object, a method for removing nitrogen oxides from exhaust gas of a diesel engine according to the present invention comprises contacting the exhaust gas of a diesel engine with an oxidation catalyst at a preceding stage to thereby remove monoxide from the exhaust gas. After oxidizing nitrogen to nitrogen dioxide, a hydrocarbon reducing agent is added to the exhaust gas on the upstream side of the latter reduction catalyst, and then the exhaust gas is brought into contact with the latter reduction catalyst to obtain nitrogen containing nitrogen dioxide generated in the former stage. A nitrogen oxides removal method for converting oxides to nitrogen gas, wherein a second component for suppressing a decrease in catalytic performance due to sulfur poisoning is attached to an oxidation catalyst in a preceding stage, thereby improving sulfur poisoning resistance of the entire denitration performance. And operating the respective reaction temperatures of the oxidation catalyst and the reduction catalyst as different temperature ranges where each catalyst exhibits the highest activity such that the oxidation catalyst is higher than the reduction catalyst. It is configured to.
【００１０】上記の本発明の方法において、酸化触媒と
しては、白金、金、銀、ロジウム、パラジウム、ルテニ
ウム、イリジウム等の貴金属をイオン交換により担持し
たゼオライトを用いることが好ましい。また、酸化触媒
に添着させる第２成分としては、ニッケル、コバルト、
ストロンチウム等の金属を用いることが好ましい。ま
た、還元触媒としては、インジウム、パラジウム、銀、
カドミウム等の金属をイオン交換により担持したゼオラ
イトを用いることが好ましい。In the above method of the present invention, it is preferable to use, as the oxidation catalyst, a zeolite carrying a noble metal such as platinum, gold, silver, rhodium, palladium, ruthenium, and iridium by ion exchange. In addition, as the second component to be impregnated with the oxidation catalyst, nickel, cobalt,
It is preferable to use a metal such as strontium. In addition, as the reduction catalyst, indium, palladium, silver,
It is preferable to use zeolite in which a metal such as cadmium is supported by ion exchange.
【００１１】また、上記の本発明の方法においては、酸
化触媒における反応温度を４００〜５００℃前後の範囲
とし、還元触媒における反応温度を２００〜４００℃前
後の範囲とすることが好ましい。また、上記の本発明の
方法において、炭化水素還元剤としては、気体状メタ
ン、エタン、プロパン、ヘキサン等の飽和炭化水素、エ
チレン、プロピレン、ヘキセン等の不飽和炭化水素、液
体状ガソリン、灯油、軽油、Ａ重油、Ｃ重油等の鉱物油
などを用いることができる。In the above method of the present invention, it is preferable that the reaction temperature of the oxidation catalyst is in the range of about 400 to 500 ° C. and the reaction temperature of the reduction catalyst is in the range of about 200 to 400 ° C. Further, in the method of the present invention, as the hydrocarbon reducing agent, gaseous methane, ethane, propane, saturated hydrocarbons such as hexane, ethylene, propylene, unsaturated hydrocarbons such as hexene, liquid gasoline, kerosene, Mineral oils such as light oil, heavy oil A and heavy oil C can be used.
【００１２】また、上記の本発明の方法においては、酸
化触媒の上流側に加熱用熱交換器を設け、酸化触媒と還
元触媒との間に冷却用熱交換器を設けて、酸化触媒及び
還元触媒における各々の反応温度を、酸化触媒の方が還
元触媒よりも高くなるような各々の触媒が最高活性を示
す異なる温度域として操作することができる（図２参
照）。また、上記の本発明の方法においては、酸化触媒
の充填層を周囲から加熱し、還元触媒の充填層を周囲か
ら冷却して、酸化触媒及び還元触媒における各々の反応
温度を、酸化触媒の方が還元触媒よりも高くなるような
各々の触媒が最高活性を示す異なる温度域として操作す
ることができる（図３参照）。In the method of the present invention, a heating heat exchanger is provided upstream of the oxidation catalyst, and a cooling heat exchanger is provided between the oxidation catalyst and the reduction catalyst. Each reaction temperature at the catalyst can be operated as a different temperature range where each catalyst exhibits the highest activity such that the oxidation catalyst is higher than the reduction catalyst (see FIG. 2). In the method of the present invention described above, the packed bed of the oxidation catalyst is heated from the surroundings, and the packed bed of the reducing catalyst is cooled from the surroundings, so that the respective reaction temperatures of the oxidation catalyst and the reduction catalyst are reduced. Can be operated at different temperature ranges where each catalyst is at its highest activity, such that is higher than the reduction catalyst (see FIG. 3).
【００１３】また、本発明の方法は、酸化触媒から出た
排ガスが還元触媒へ流れる流路に冷却用熱交換器を設
け、かつ、還元触媒から出た排ガスの流路内に酸化触媒
を設置して、還元触媒で昇温された高温の排ガスの熱を
利用して酸化触媒の加熱を行うことを特徴としている
（図４、図５参照）。また、本発明の方法は、還元触媒
から出た排ガスの流路内に酸化触媒を設置して、還元触
媒で昇温された高温の排ガスの熱を利用して酸化触媒の
加熱を行うとともに、酸化触媒から出た排ガスが還元触
媒へ流れる流路に熱交換器を設置し、該熱交換器で酸化
触媒に導入前の排ガスと熱交換して、酸化触媒から出た
高温の排ガスの冷却を行い、還元触媒に導入する排ガス
の温度を酸化触媒の出口温度より低温にすることを特徴
としている（図６参照）。[0013] In the method of the present invention, a cooling heat exchanger is provided in a flow path in which exhaust gas discharged from the oxidation catalyst flows to the reduction catalyst, and an oxidation catalyst is provided in a flow path of exhaust gas discharged from the reduction catalyst. Then, the oxidation catalyst is heated using the heat of the high-temperature exhaust gas heated by the reduction catalyst (see FIGS. 4 and 5). Further, the method of the present invention is to install an oxidation catalyst in the flow path of the exhaust gas discharged from the reduction catalyst, and to heat the oxidation catalyst using the heat of the high-temperature exhaust gas heated by the reduction catalyst, A heat exchanger is installed in the flow path where the exhaust gas from the oxidation catalyst flows to the reduction catalyst, and the heat exchanger exchanges heat with the exhaust gas before being introduced into the oxidation catalyst to cool the high-temperature exhaust gas from the oxidation catalyst. This is characterized in that the temperature of the exhaust gas introduced into the reduction catalyst is made lower than the outlet temperature of the oxidation catalyst (see FIG. 6).
【００１４】本発明の窒素酸化物除去装置は、ディーゼ
ルエンジン排ガス中の一酸化窒素を二酸化窒素に酸化す
るための酸化触媒を充填し、かつ、酸化触媒に全体の脱
硝性能の硫黄被毒耐性を高めるための第２成分を添着さ
せた酸化反応手段と、酸化反応手段の上流に設けられた
酸化触媒が最高活性を示す４００〜５００℃の温度域に
温度調整するための加熱用熱交換器と、酸化反応手段の
下流に設けられた排ガスに炭化水素還元剤を添加するた
めの還元剤添加手段と、還元剤添加手段の下流に設けら
れた排ガス中の二酸化窒素を含む窒素酸化物を窒素ガス
に還元するための還元触媒を充填した還元反応手段と、
還元反応手段の上流に設けられた還元触媒が最高活性を
示す２００〜４００℃の温度域に温度調整するための冷
却用熱交換器とを備えたことを特徴としている（図２参
照）。The nitrogen oxide removing apparatus of the present invention is filled with an oxidation catalyst for oxidizing nitrogen monoxide in diesel engine exhaust gas to nitrogen dioxide, and the oxidation catalyst is provided with sulfur poisoning resistance of the entire denitration performance. An oxidation reaction means to which a second component for increasing the temperature is attached; and a heating heat exchanger for adjusting the temperature to a temperature range of 400 to 500 ° C. in which an oxidation catalyst provided upstream of the oxidation reaction means has the highest activity. A reducing agent adding means for adding a hydrocarbon reducing agent to the exhaust gas provided downstream of the oxidation reaction means, and a nitrogen gas containing nitrogen dioxide in the exhaust gas provided downstream of the reducing agent adding means. Reduction reaction means filled with a reduction catalyst for reduction to
It is characterized in that it comprises a cooling heat exchanger for adjusting the temperature to a temperature range of 200 to 400 ° C. where the reduction catalyst provided upstream of the reduction reaction means exhibits the highest activity (see FIG. 2).
【００１５】また、本発明の装置は、ディーゼルエンジ
ン排ガス中の一酸化窒素を二酸化窒素に酸化するための
酸化触媒を充填し、かつ、酸化触媒に全体の脱硝性能の
硫黄被毒耐性を高めるための第２成分を添着させた酸化
反応手段と、酸化反応手段に装着された酸化触媒が最高
活性を示す４００〜５００℃の温度域に温度調整するた
めのジャケット構造の加熱手段と、酸化反応手段の下流
に設けられた排ガスに炭化水素還元剤を添加するための
還元剤添加手段と、還元剤添加手段の下流に設けられた
排ガス中の二酸化窒素を含む窒素酸化物を窒素ガスに還
元するための還元触媒を充填した還元反応手段と、還元
反応手段に装着された還元触媒が最高活性を示す２００
〜４００℃の温度域に温度調整するためのジャケット構
造の冷却手段とを備えたことを特徴としている（図３参
照）。Further, the apparatus of the present invention fills an oxidation catalyst for oxidizing nitrogen monoxide in a diesel engine exhaust gas to nitrogen dioxide, and enhances the oxidation catalyst to have sulfur poisoning resistance of the entire denitration performance. Oxidation means having the second component impregnated therein, heating means having a jacket structure for adjusting the temperature to a temperature range of 400 to 500 ° C. in which the oxidation catalyst mounted on the oxidation reaction means exhibits the highest activity, and oxidation reaction means A reducing agent adding means for adding a hydrocarbon reducing agent to exhaust gas provided downstream of the apparatus, and reducing nitrogen oxides containing nitrogen dioxide in the exhaust gas provided downstream of the reducing agent adding means to nitrogen gas. And the reduction catalyst mounted on the reduction reaction means exhibits the highest activity.
A cooling means having a jacket structure for adjusting the temperature to a temperature range of up to 400 ° C. is provided (see FIG. 3).
【００１６】また、本発明の装置は、ディーゼルエンジ
ン排ガス中の一酸化窒素を二酸化窒素に酸化するための
酸化触媒を充填した酸化反応手段と、酸化反応手段の下
流の排ガス流路に設けられた排ガスに炭化水素還元剤を
添加するための還元剤添加手段と、還元剤添加手段の下
流の排ガス流路に設けられた排ガス中の二酸化窒素を含
む窒素酸化物を窒素ガスに還元するための還元触媒を充
填した還元反応手段と、酸化反応手段と還元反応手段と
の間の排ガス流路に設けられた冷却用熱交換器とを備
え、酸化触媒を充填した酸化反応手段が還元反応手段の
下流の排ガス流路内に配置されており、還元触媒で昇温
された高温の排ガスの熱を利用して酸化触媒の加熱が行
われるようにしたことを特徴としている（図４、図５参
照）。The apparatus of the present invention is provided in an oxidation reaction means filled with an oxidation catalyst for oxidizing nitrogen monoxide in diesel exhaust gas to nitrogen dioxide, and in an exhaust gas flow path downstream of the oxidation reaction means. Reducing agent adding means for adding a hydrocarbon reducing agent to the exhaust gas, and reduction for reducing nitrogen oxides including nitrogen dioxide in the exhaust gas provided in the exhaust gas flow path downstream of the reducing agent adding means to nitrogen gas A reduction reaction means filled with a catalyst, and a cooling heat exchanger provided in an exhaust gas passage between the oxidation reaction means and the reduction reaction means, wherein the oxidation reaction means filled with the oxidation catalyst is downstream of the reduction reaction means In which the oxidation catalyst is heated by using the heat of the high-temperature exhaust gas heated by the reduction catalyst (see FIGS. 4 and 5). .
【００１７】また、本発明の装置は、ディーゼルエンジ
ン排ガス中の一酸化窒素を二酸化窒素に酸化するための
酸化触媒を充填した酸化反応手段と、酸化反応手段の下
流の排ガス流路に設けられた排ガスに炭化水素還元剤を
添加するための還元剤添加手段と、還元剤添加手段の下
流の排ガス流路に設けられた排ガス中の二酸化窒素を含
む窒素酸化物を窒素ガスに還元するための還元触媒を充
填した還元反応手段とを備え、酸化触媒を充填した酸化
反応手段が還元反応手段の下流の排ガス流路内に配置さ
れており、還元触媒で昇温された高温の排ガスの熱を利
用して酸化触媒の加熱が行われるようにし、かつ、酸化
反応手段と還元反応手段との間の排ガス流路に熱交換器
が設けられ、該熱交換器が酸化反応手段の上流の排ガス
流路に設置されるようにして、酸化触媒から出た高温の
排ガスが入口ガスと熱交換して冷却され、還元触媒に導
入する排ガスの温度が酸化触媒の出口温度より低温にな
るようにしたことを特徴としている（図６参照）。Further, the apparatus of the present invention is provided in an oxidation reaction means filled with an oxidation catalyst for oxidizing nitrogen monoxide in diesel engine exhaust gas to nitrogen dioxide, and in an exhaust gas flow path downstream of the oxidation reaction means. Reducing agent adding means for adding a hydrocarbon reducing agent to the exhaust gas, and reduction for reducing nitrogen oxides including nitrogen dioxide in the exhaust gas provided in the exhaust gas flow path downstream of the reducing agent adding means to nitrogen gas A reduction reaction means filled with a catalyst, and the oxidation reaction means filled with an oxidation catalyst is arranged in an exhaust gas flow path downstream of the reduction reaction means, and uses heat of high-temperature exhaust gas heated by the reduction catalyst. So that the oxidation catalyst is heated, and a heat exchanger is provided in an exhaust gas flow path between the oxidation reaction means and the reduction reaction means, and the heat exchanger is disposed in an exhaust gas flow path upstream of the oxidation reaction means. Installed in Thus, the high-temperature exhaust gas discharged from the oxidation catalyst is cooled by exchanging heat with the inlet gas, so that the temperature of the exhaust gas introduced into the reduction catalyst is lower than the outlet temperature of the oxidation catalyst ( See FIG. 6).
【００１８】これらの還元触媒で昇温された高温排ガス
の熱を利用して酸化触媒の加熱を行う装置においては、
酸化触媒に全体の脱硝性能の硫黄被毒耐性を高めるため
の第２成分を添着させた酸化反応手段を適用することが
好ましい。In an apparatus for heating an oxidation catalyst by using heat of high-temperature exhaust gas heated by these reduction catalysts,
It is preferable to apply an oxidation reaction means in which a second component for improving the sulfur poisoning resistance of the entire denitration performance is attached to the oxidation catalyst.
【００１９】[0019]
【発明の実施の形態】以下、本発明の実施の形態につい
て説明するが、本発明は下記の実施の形態に何ら限定さ
れるものではなく、適宜変更して実施することが可能な
ものである。図１は、本発明のディーゼルエンジン排ガ
ス中の窒素酸化物除去方法の概念を模式的に示してお
り、微量の一酸化窒素と高濃度の酸素、さらに硫黄酸化
物を含有するディーゼルエンジン排ガスは、前段の酸化
触媒１０にて一酸化窒素が二酸化窒素に酸化され、後段
の還元触媒１２に導入される前に炭化水素還元剤が添加
されて、還元触媒１２にて生成した二酸化窒素を含む窒
素酸化物が窒素ガスに効率よく転換される。また、前段
の酸化触媒１０にＳＯx被毒を低く抑えるための第２成
分を添着させることにより、全体の脱硝性能の硫黄被毒
耐性を高めることができる。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications. . FIG. 1 schematically shows the concept of the method for removing nitrogen oxides from diesel engine exhaust gas of the present invention. A diesel engine exhaust gas containing a trace amount of nitric oxide and a high concentration of oxygen, and further containing sulfur oxides, Nitrogen monoxide is oxidized to nitrogen dioxide by the oxidation catalyst 10 in the first stage, and a hydrocarbon reducing agent is added before being introduced into the reduction catalyst 12 in the second stage. The material is efficiently converted to nitrogen gas. Further, by adhering the second component for suppressing SOx poisoning to the oxidation catalyst 10 at the former stage, the sulfur poisoning resistance of the entire denitration performance can be increased.
【００２０】低温、かつ高濃度の酸素、硫黄酸化物をも
含有するディーゼルエンジン排ガスは、酸化触媒１０に
おいて、又は酸化触媒１０に導入される前に、酸化触媒
１０が最高活性を示す温度範囲である４００〜５００℃
前後に昇温され、酸化触媒１０からの出口ガスは、還元
触媒１２において、又は還元触媒１２に導入される前
に、還元触媒１２が最高活性を示す温度範囲である２０
０〜４００℃前後、望ましくは３００〜４００℃前後に
温度調整される。このように、酸化触媒及び還元触媒に
おける各々の反応温度を、酸化触媒の方が還元触媒より
も高くなるような各々の触媒が最高活性を示す異なる操
作温度域とする。Diesel engine exhaust gas, which is low in temperature and also contains high concentrations of oxygen and sulfur oxides, may be introduced into the oxidation catalyst 10 or before being introduced into the oxidation catalyst 10 in a temperature range in which the oxidation catalyst 10 exhibits the highest activity. Some 400-500 ° C
The temperature of the outlet gas from the oxidation catalyst 10 which has been heated up and down is in a temperature range where the reduction catalyst 12 exhibits the highest activity at or before being introduced into the reduction catalyst 12.
The temperature is adjusted to about 0 to 400 ° C, preferably about 300 to 400 ° C. Thus, the respective reaction temperatures of the oxidation catalyst and the reduction catalyst are set to different operating temperature ranges in which the respective catalysts exhibit the highest activity such that the oxidation catalyst is higher than the reduction catalyst.
【００２１】図２は、本発明の実施の第１形態によるデ
ィーゼルエンジン排ガス中の窒素酸化物除去装置の一例
を示しており、酸化触媒、還元触媒それぞれの上流側に
熱交換器を設置している。図２に示すように、ディーゼ
ルエンジン排ガスを酸化触媒１４に適した温度まで上昇
させることを目的とした熱交換器１６と、酸化触媒１４
から排出される出口ガスを還元触媒１８に適した温度ま
で低下させることを目的とした熱交換器２０を備えてい
る。この場合、炭化水素還元剤は熱交換器２０と還元触
媒１８の間から供給するが、還元剤の導入により出口ガ
ス温度が還元触媒１８に適した温度に低減されるなら
ば、熱交換器２０の使用は不要となる。また、還元剤の
導入により出口ガス温度が下がりすぎる場合は、熱交換
器２０で排ガスの温度を上昇させる必要がある。FIG. 2 shows an example of an apparatus for removing nitrogen oxides from exhaust gas of a diesel engine according to a first embodiment of the present invention, in which a heat exchanger is installed upstream of each of an oxidation catalyst and a reduction catalyst. I have. As shown in FIG. 2, a heat exchanger 16 for raising the exhaust gas of the diesel engine to a temperature suitable for the oxidation catalyst 14,
Is provided with a heat exchanger 20 for the purpose of lowering the outlet gas discharged from the reactor to a temperature suitable for the reduction catalyst 18. In this case, the hydrocarbon reducing agent is supplied from between the heat exchanger 20 and the reduction catalyst 18, but if the outlet gas temperature is reduced to a temperature suitable for the reduction catalyst 18 by introducing the reducing agent, the heat exchanger 20 The use of is unnecessary. If the outlet gas temperature is too low due to the introduction of the reducing agent, it is necessary to increase the temperature of the exhaust gas in the heat exchanger 20.
【００２２】本実施の形態で使用する酸化触媒として
は、白金、金、銀、ロジウム、パラジウム、ルテニウ
ム、イリジウム等の貴金属をイオン交換により担持した
ゼオライトを使用することができる。また、第２成分と
して、ニッケル、コバルト、ストロンチウム等の金属を
酸化触媒に添着させる。これらの触媒は、粒状、ハニカ
ム状、ハニカム担体にディップコートしたもののいずれ
でも使用可能である。本実施の形態で使用する還元触媒
としては、インジウム、パラジウム、銀、カドミウム等
の金属をイオン交換により担持したゼオライトを使用す
ることができる。これらの触媒は、粒状、ハニカム状、
ハニカム担体にディップコートしたもののいずれでも使
用可能である。また、炭化水素還元剤としては、気体状
メタン、エタン、プロパン、ヘキサン等の飽和炭化水
素、エチレン、プロピレン、ヘキセン等の不飽和炭化水
素、液体状ガソリン、灯油、軽油、Ａ重油、Ｃ重油等の
上記の炭化水素等を構成成分として含有する鉱物油など
を使用することができる。As the oxidation catalyst used in the present embodiment, a zeolite carrying a noble metal such as platinum, gold, silver, rhodium, palladium, ruthenium, and iridium by ion exchange can be used. Further, as the second component, a metal such as nickel, cobalt, and strontium is attached to the oxidation catalyst. These catalysts can be used in any of granular, honeycomb, and dip-coated honeycomb supports. As the reduction catalyst used in the present embodiment, zeolite in which metals such as indium, palladium, silver, and cadmium are supported by ion exchange can be used. These catalysts are granular, honeycomb,
Any one obtained by dip coating a honeycomb carrier can be used. Examples of the hydrocarbon reducing agent include saturated hydrocarbons such as gaseous methane, ethane, propane and hexane, unsaturated hydrocarbons such as ethylene, propylene and hexene, liquid gasoline, kerosene, light oil, heavy oil A, heavy oil C and the like. Mineral oils and the like containing the above hydrocarbons and the like as constituent components can be used.
【００２３】図３は、本発明の実施の第２形態によるデ
ィーゼルエンジン排ガス中の窒素酸化物除去装置の一例
を示しており、酸化触媒にジャケット構造の熱交換器又
はヒータ、還元触媒にジャケット構造の熱交換器又はク
ーラが装着されている。図３に示すように、ディーゼル
エンジン排ガスを酸化触媒２２に適した温度まで上昇さ
せることを目的としたジャケット構造の熱交換器２４
と、酸化触媒２２から排出される出口ガスを還元触媒２
６に適した温度まで低下させることを目的としたジャケ
ット構造の熱交換器２８を備えている。炭化水素還元剤
は酸化触媒２２と還元触媒２６の間で添加される。この
場合、還元剤の導入により出口ガス温度が還元触媒２６
に適した温度に低減されるならば、熱交換器２８の使用
は不要となる。また、還元剤の導入により出口ガス温度
が下がりすぎる場合は、熱交換器２８で排ガスの温度を
上昇させる必要がある。使用する触媒、還元剤等は、実
施の第１形態の場合と同様である。FIG. 3 shows an example of an apparatus for removing nitrogen oxides from exhaust gas of a diesel engine according to a second embodiment of the present invention. A heat exchanger or heater having a jacket structure for an oxidation catalyst and a jacket structure for a reduction catalyst. Heat exchanger or cooler is installed. As shown in FIG. 3, a heat exchanger 24 having a jacket structure for the purpose of raising the exhaust gas of the diesel engine to a temperature suitable for the oxidation catalyst 22.
And the outlet gas discharged from the oxidation catalyst 22
6 is provided with a heat exchanger 28 having a jacket structure for the purpose of lowering the temperature to a temperature suitable for 6. The hydrocarbon reducing agent is added between the oxidation catalyst 22 and the reduction catalyst 26. In this case, the outlet gas temperature is reduced by the introduction of the reducing agent.
If the temperature is reduced to a suitable temperature, the use of the heat exchanger 28 becomes unnecessary. If the outlet gas temperature is too low due to the introduction of the reducing agent, it is necessary to increase the temperature of the exhaust gas in the heat exchanger 28. The catalysts, reducing agents, and the like used are the same as in the first embodiment.
【００２４】図４は、本発明の実施の第３形態によるデ
ィーゼルエンジン排ガス中の窒素酸化物除去装置の一例
を示しており、還元触媒の前に冷却用の熱交換器を設
け、かつ、還元触媒から出た排ガスの流路内に酸化触媒
を設置して、還元触媒で昇温された高温の排ガスの熱を
利用して酸化触媒の加熱を行うものである。図４に示す
ように、酸化触媒３０の上流の排ガス流路３２に三方切
替コック３４を設け、酸化触媒３０の下流の排ガス流路
３６に三方切替コック３８を設け、三方切替コック３
４、３８の間にバイパス流路４０を設ける。三方切替コ
ック３８の下流に熱交換器４２、その下流に還元触媒４
４を備えており、炭化水素還元剤は還元触媒４４の手前
で添加される。還元触媒４４の下流の排ガス流路４６内
に酸化触媒３０を設置して熱交換が行えるようにする。
なお、酸化触媒３０に接続される排ガス流路３２、３６
は排ガス流路４６を貫通しており、互いの排ガスが混合
されることはない。FIG. 4 shows an example of an apparatus for removing nitrogen oxides from exhaust gas of a diesel engine according to a third embodiment of the present invention, in which a heat exchanger for cooling is provided before a reduction catalyst, and An oxidation catalyst is installed in the flow path of the exhaust gas discharged from the catalyst, and the oxidation catalyst is heated by utilizing the heat of the high-temperature exhaust gas heated by the reduction catalyst. As shown in FIG. 4, a three-way switching cock 34 is provided in an exhaust gas flow path 32 upstream of the oxidation catalyst 30, and a three-way switching cock 38 is provided in an exhaust gas flow path 36 downstream of the oxidation catalyst 30.
A bypass flow path 40 is provided between 4 and 38. A heat exchanger 42 is provided downstream of the three-way switching cock 38, and the reduction catalyst 4 is provided downstream thereof.
4 and the hydrocarbon reducing agent is added before the reduction catalyst 44. The oxidation catalyst 30 is provided in the exhaust gas passage 46 downstream of the reduction catalyst 44 so that heat exchange can be performed.
The exhaust gas passages 32 and 36 connected to the oxidation catalyst 30
Are passed through the exhaust gas passage 46, and the exhaust gases are not mixed with each other.
【００２５】この装置では、まず、排ガスがバイパス流
路４０を経由して流路を流れるように三方切替コック
３４、３８を切り替え、還元触媒４４にて排ガスの脱硝
反応を行わせることにより、還元触媒４４からの出口ガ
ス温度を高温状態にして、排ガス流路４６内に設置され
た酸化触媒３０を加熱する。つぎに、酸化触媒３０が排
ガス酸化反応に十分な温度まで上昇した後、排ガスが流
路を流れるように三方切替コック３４、３８を切り替
え、酸化触媒３０と還元触媒４４の組み合わせにより脱
硝反応を行う。使用する触媒、還元剤等は、実施の第１
形態の場合と同様である。In this apparatus, first, the three-way switching cocks 34 and 38 are switched so that the exhaust gas flows through the bypass passage 40 and the exhaust gas is denitrated by the reduction catalyst 44, thereby reducing the exhaust gas. The temperature of the outlet gas from the catalyst 44 is set to a high temperature, and the oxidation catalyst 30 installed in the exhaust gas channel 46 is heated. Next, after the oxidation catalyst 30 rises to a temperature sufficient for the exhaust gas oxidation reaction, the three-way switching cocks 34 and 38 are switched so that the exhaust gas flows through the flow path, and the denitration reaction is performed by the combination of the oxidation catalyst 30 and the reduction catalyst 44. . The catalyst and reducing agent used are the first
This is the same as in the case of the form.
【００２６】図５は、本発明の実施の第４形態によるデ
ィーゼルエンジン排ガス中の窒素酸化物除去装置の一例
を示しており、還元触媒の前に冷却用の熱交換器を設
け、かつ、還元触媒から出た排ガスの流路内に酸化触媒
を設置して、還元触媒で昇温された高温の排ガスの熱を
利用して酸化触媒の加熱を行うものである。本実施の形
態は、図４のように切替コックを必要とせず、還元触媒
４８からの出口ガスによる酸化触媒５０の加熱と、酸化
触媒５０と還元触媒４８の組み合わせによる脱硝反応
を、排ガス導入と同時に行う方式である。すなわち、図
５に示すように、還元触媒４８の下流の排ガス流路５２
内に酸化触媒５０を設置して熱交換が行えるようにし、
酸化触媒５０の下流に熱交換器５４、その下流に還元触
媒４８を備えており、炭化水素還元剤は還元触媒４８の
手前で添加されるように構成されている。他の構成及び
作用等は、上述した実施の第３形態において排ガスが流
路を流れる場合と同様である。FIG. 5 shows an example of an apparatus for removing nitrogen oxides from exhaust gas of a diesel engine according to a fourth embodiment of the present invention, in which a heat exchanger for cooling is provided before a reduction catalyst, and An oxidation catalyst is installed in the flow path of the exhaust gas discharged from the catalyst, and the oxidation catalyst is heated by utilizing the heat of the high-temperature exhaust gas heated by the reduction catalyst. This embodiment does not require a switching cock as shown in FIG. 4, and performs heating of the oxidation catalyst 50 by an outlet gas from the reduction catalyst 48 and denitration reaction by a combination of the oxidation catalyst 50 and the reduction catalyst 48 with introduction of exhaust gas. This is a method that is performed simultaneously. That is, as shown in FIG.
An oxidation catalyst 50 is installed inside to allow heat exchange,
A heat exchanger 54 is provided downstream of the oxidation catalyst 50, and a reduction catalyst 48 is provided downstream of the heat exchanger 54. The hydrocarbon reducing agent is configured to be added before the reduction catalyst 48. Other configurations, operations, and the like are the same as those in the case where the exhaust gas flows through the flow channel in the third embodiment described above.
【００２７】図６は、本発明の実施の第５形態によるデ
ィーゼルエンジン排ガス中の窒素酸化物除去装置の一例
を示しており、還元触媒で昇温された高温の排ガスの熱
を利用して酸化触媒の加熱を行い、かつ、還元触媒に導
入する排ガスの温度を酸化触媒の出口温度よりは低温に
するために、酸化触媒から出た高温の排ガスを入口ガス
と熱交換して冷却を行い、外部熱源と不要としたもので
ある。図６に示すように、酸化触媒５６を還元触媒５８
の下流の排ガス流路６０内に設置し、酸化触媒５６と還
元触媒５８の間の排ガス流路６２に熱交換器６４を設
け、熱交換器６４に酸化触媒５６の上流の排ガス流路６
６が通るようにする。酸化触媒５６は、還元触媒５８で
の反応熱により昇温された高温排ガスで酸化反応に適し
た温度に加熱され、酸化触媒５６からの出口ガスは、熱
交換器６４にて入口ガスを用いて冷却され、脱硝反応に
適した温度となって還元触媒５８に導入される。なお、
炭化水素還元剤は還元触媒５８の手前で添加される。使
用する触媒、還元剤等は、実施の第１形態の場合と同様
である。FIG. 6 shows an example of an apparatus for removing nitrogen oxides from exhaust gas of a diesel engine according to a fifth embodiment of the present invention. In order to heat the catalyst, and to make the temperature of the exhaust gas introduced into the reduction catalyst lower than the outlet temperature of the oxidation catalyst, the high-temperature exhaust gas discharged from the oxidation catalyst is cooled by heat exchange with the inlet gas, External heat source and unnecessary. As shown in FIG. 6, the oxidation catalyst 56 is replaced with a reduction catalyst 58.
The heat exchanger 64 is provided in the exhaust gas passage 62 between the oxidation catalyst 56 and the reduction catalyst 58, and the heat exchanger 64 is provided in the exhaust gas passage 6 upstream of the oxidation catalyst 56.
Allow 6 to pass. The oxidation catalyst 56 is heated to a temperature suitable for the oxidation reaction by the high temperature exhaust gas heated by the reaction heat in the reduction catalyst 58, and the outlet gas from the oxidation catalyst 56 is supplied to the heat exchanger 64 using the inlet gas. The mixture is cooled and brought to a temperature suitable for the denitration reaction and introduced into the reduction catalyst 58. In addition,
The hydrocarbon reducing agent is added before the reduction catalyst 58. The catalysts, reducing agents, and the like used are the same as in the first embodiment.
【００２８】[0028]
【実施例】以下、実施例により本発明をさらに詳しく説
明する。本実施例では、酸化触媒として白金触媒、第２
成分としてニッケル、還元触媒としてインジウム触媒を
使用した。 （１）白金担持ゼオライト触媒の調製 触媒種類は粒状、ハニカム状、ハニカム担体にディップ
コートしたもののいずれでもよいが、本実施例では粒状
触媒を使用した。触媒の調製方法は以下のとおりであ
る。ＭＦＩ型ゼオライト触媒を、所定濃度に溶解したテ
トラアンミンジクロロ白金一水和物（［Ｐｔ（Ｎ
Ｈ3）4］Ｃｌ2・Ｈ2Ｏ）水溶液中に攪拌混合し、白金金
属種をイオン交換担持させた。これを一昼夜１１０℃で
乾燥させた後、空気雰囲気下５５０℃で５時間焼成し
た。触媒の担持量は１wt％であった。The present invention will be described in more detail with reference to the following examples. In this embodiment, a platinum catalyst as the oxidation catalyst,
Nickel was used as a component, and an indium catalyst was used as a reduction catalyst. (1) Preparation of Platinum-Supported Zeolite Catalyst The type of catalyst may be any of granular, honeycomb, and dip-coated on a honeycomb carrier. In the present embodiment, a granular catalyst was used. The method for preparing the catalyst is as follows. MFI-type zeolite catalyst was dissolved in a predetermined concentration in tetraamminedichloroplatinum monohydrate ([Pt (N
H 3 ) 4 ] Cl 2 .H 2 O) aqueous solution was stirred and mixed to carry platinum metal species by ion exchange. After drying at 110 ° C. for one day and night, it was baked at 550 ° C. for 5 hours in an air atmosphere. The supported amount of the catalyst was 1% by weight.
【００２９】（２）白金＋ニッケル担持ゼオライト触媒
の調製 触媒種類は粒状、ハニカム状、ハニカム担体にディップ
コートしたもののいずれでもよいが、本実施例では粒状
触媒を使用した。触媒の調製方法は以下のとおりであ
る。ＭＦＩ型ゼオライト触媒を、所定濃度に溶解したテ
トラアンミンジクロロ白金一水和物（［Ｐｔ（Ｎ
Ｈ3）4］Ｃｌ2・Ｈ2Ｏ）水溶液中に攪拌混合し、白金金
属種をイオン交換担持させた。ついで、所定濃度に溶解
した酢酸ニッケル四水和物（（ＣＨ3ＣＯＯ）2Ｎｉ・４
Ｈ2Ｏ）水溶液中に攪拌混合し、ニッケル金属種をイオ
ン交換担持させた。これを一昼夜１１０℃で乾燥させた
後、空気雰囲気下５５０℃で５時間焼成した。触媒の担
持量は１wt％であった。(2) Preparation of Platinum + Nickel-Supported Zeolite Catalyst The type of catalyst may be any of a granular form, a honeycomb form, and a dip-coated honeycomb support. In the present embodiment, a granular catalyst was used. The method for preparing the catalyst is as follows. MFI-type zeolite catalyst was dissolved in a predetermined concentration in tetraamminedichloroplatinum monohydrate ([Pt (N
H 3 ) 4 ] Cl 2 .H 2 O) aqueous solution was stirred and mixed to carry platinum metal species by ion exchange. Next, nickel acetate tetrahydrate ((CH 3 COO) 2 Ni · 4
The mixture was stirred and mixed in an aqueous solution of H 2 O) to carry a nickel metal species by ion exchange. After drying at 110 ° C. for one day and night, it was baked at 550 ° C. for 5 hours in an air atmosphere. The supported amount of the catalyst was 1% by weight.
【００３０】（３）インジウム担持ゼオライト触媒の調
製 触媒種類は粒状、ハニカム状、ハニカム担体にディップ
コートしたもののいずれでもよいが、本実施例では粒状
触媒を使用した。触媒の調製方法は以下のとおりであ
る。ＭＦＩ型ゼオライト触媒を、所定濃度に溶解した硝
酸インジウム三水和物（Ｉｎ（ＮＯ3）3・３Ｈ2Ｏ）水
溶液中に攪拌混合し、インジウム金属種をイオン交換担
持させた。これを一昼夜１１０℃で乾燥させた後、空気
雰囲気下５５０℃で５時間焼成した。触媒の担持量は１
wt％であった。(3) Preparation of Indium-Supported Zeolite Catalyst The type of catalyst may be any of a granular form, a honeycomb form, and a dip-coated honeycomb support, but in this embodiment, a granular catalyst was used. The method for preparing the catalyst is as follows. The MFI-type zeolite catalyst was stirred and mixed into an aqueous solution of indium nitrate trihydrate (In (NO 3 ) 3 .3H 2 O) dissolved at a predetermined concentration to carry out indium metal species by ion exchange. After drying at 110 ° C. for one day and night, it was baked at 550 ° C. for 5 hours in an air atmosphere. The amount of catalyst supported is 1
wt%.
【００３１】（４）試験装置、試験方法 図７に示す試験装置により脱硝性能評価を行った。反応
ガスは標準ガスボンベより供給し、バランスガスはＮ2
とした。水蒸気はマスフローによりコントロールされた
蒸留水を蒸発器により完全に気化させて供給した。触媒
は石英製の反応管に所定量を石英製ビーズを上下に挟み
込む形で装填した。そして、前段の反応管６８に酸化触
媒、後段の反応管７０に還元触媒を配した。それぞれの
反応管には温度調整装置（ヒーター、クーラー）を設け
た。ゼオライト触媒は粒径１．４〜２．８mmに整えたも
のを所定ＡＶ相当量（面積当たりの流量）装填した。炭
化水素還元剤としてはプロピレンを使用し、プロピレン
は前段の反応管６８と後段の反応管７０の間から供給し
た。脱硝反応後のガスは、冷却器により水分を除去し、
ＮＯx計、Ｎ2Ｏ計を用いてＮＯx、Ｎ2Ｏ濃度を測定し
た。ＮＯx計、Ｎ2Ｏ計はそれぞれ化学発光式、赤外式で
ある。評価項目は、導入したガス中の全ＮＯx量に対す
る出口ガスの、Ｎ2生成率、Ｎ2Ｏ生成率、ＮＯx
残存率、である。ガス条件等を下記の表１にまとめる。(4) Test Apparatus and Test Method Denitration performance was evaluated using the test apparatus shown in FIG. The reaction gas is supplied from a standard gas cylinder and the balance gas is N 2
And Steam was supplied by completely vaporizing distilled water controlled by mass flow by an evaporator. A predetermined amount of the catalyst was loaded into a quartz reaction tube in such a manner that quartz beads were vertically sandwiched therebetween. Then, an oxidation catalyst was provided in the first reaction tube 68, and a reduction catalyst was provided in the second reaction tube 70. Each reaction tube was provided with a temperature controller (heater, cooler). The zeolite catalyst adjusted to a particle size of 1.4 to 2.8 mm was loaded in an amount corresponding to a predetermined AV (flow rate per area). Propylene was used as the hydrocarbon reducing agent, and propylene was supplied from between the former reaction tube 68 and the latter reaction tube 70. The gas after the denitration reaction removes moisture with a cooler,
NOx meter, by using the N 2 O meter measures NOx, the N 2 O concentration. NOx meter, respectively N 2 O meter chemiluminescence, an infrared type. The evaluation items were N 2 generation rate, N 2 O generation rate, NOx
Survival rate. Table 1 below summarizes the gas conditions and the like.
【００３２】[0032]
【表１】 [Table 1]
【００３３】２段機能分割型複合触媒として、前段に白
金＋ニッケル担持ゼオライト触媒、後段にインジウム担
持ゼオライト触媒を配したものを本発明の実施例とし
た。また、２段機能分割型複合触媒として、前段に白金
担持ゼオライト触媒、後段にインジウム担持ゼオライト
触媒を配したものを比較例とした。比較例における試験
装置、試験方法は本発明の実施例と同様である。また、
表１に示すように、反応温度は、前段の触媒を４１０
℃、後段の触媒を３９０℃として試験を行った。これら
の２種類の試験を実施し、比較検討を行った。実施した
試験の手順は、まず、ＳＯ2：０ppmのガスで脱硝反応を
行い、各評価項目を計測した。次に、ＳＯ2：５００ppm
のガスを導入し、脱硝反応を行わせながら一晩経過後、
各評価項目を計測した。また、ＳＯx被毒試験後、バラ
ンスガスであるＮ2の流通下、触媒層温度５００℃にて
触媒再生を行い、その後、ＳＯ2：０ppmのガスで脱硝反
応を行い、各評価項目を計測した。As a two-stage function-separated composite catalyst, a platinum / nickel-supported zeolite catalyst was disposed in the front stage and an indium-supported zeolite catalyst was disposed in the rear stage, which was an embodiment of the present invention. In addition, as a two-stage function-separated composite catalyst, a catalyst in which a platinum-supported zeolite catalyst was disposed in the front stage and an indium-supported zeolite catalyst was disposed in the rear stage was used as a comparative example. The test apparatus and test method in the comparative example are the same as those in the example of the present invention. Also,
As shown in Table 1, the reaction temperature was 410
The test was carried out at a temperature of 390 ° C. and the temperature of the subsequent catalyst at 390 ° C. These two types of tests were performed, and a comparative study was performed. In the procedure of the test performed, first, a denitration reaction was performed with a gas of SO 2 : 0 ppm, and each evaluation item was measured. Next, SO 2 : 500 ppm
After passing over night while introducing the gas and performing the denitration reaction,
Each evaluation item was measured. Further, after the SOx poisoning test, the catalyst was regenerated at a catalyst layer temperature of 500 ° C. under the flow of N 2 as a balance gas, and thereafter, a denitration reaction was performed with a gas of SO 2 : 0 ppm, and each evaluation item was measured. .
【００３４】（５）試験結果 図８、図９に、ＳＯx被毒前、ＳＯx被毒後、触媒再生後
のＮ2生成率、Ｎ2Ｏ生成率、ＮＯx残存率の変化を示
す。図８は本発明の実施例の結果であり、図９は比較例
の結果である。いずれの脱硝試験においても、ＳＯx被
毒前は、高いＮ2生成率を示しており、亜酸化窒素（Ｎ2
Ｏ）の発生もほとんどない。しかしながら、ＳＯx被毒
試験の結果からわかるように、本発明の実施例では、Ｓ
Ｏ2導入量５００ppmという非常に過酷な条件下でありな
がら、比較例の場合と比較して、ＳＯx被毒後の触媒性
能の劣化程度が低く抑えられていることがわかる。ま
た、図１０にＳＯx被毒後のＮＯx除去率の経時変化を示
す。図１０の結果から、本発明の実施例の方が、ＳＯx
被毒による触媒性能の低下度合いが少ないことがわか
る。(5) Test Results FIGS. 8 and 9 show changes in N 2 generation rate, N 2 O generation rate, and NOx residual rate before SOx poisoning, after SOx poisoning, and after catalyst regeneration. FIG. 8 shows the result of the example of the present invention, and FIG. 9 shows the result of the comparative example. In any of the denitration tests, a high N 2 generation rate was shown before SOx poisoning, and nitrous oxide (N 2
O) hardly occurs. However, as can be seen from the results of the SOx poisoning test, in the embodiment of the present invention, S
Yet very severe conditions of O 2 introduction amount 500 ppm, as compared with the case of the comparative example, it can be seen that the degree of deterioration of the catalyst performance after SOx poisoning is low. FIG. 10 shows the change over time in the NOx removal rate after SOx poisoning. From the results of FIG. 10, it is clear that the embodiment of the present invention has a higher SOx
It can be seen that the degree of deterioration of the catalyst performance due to poisoning is small.
【００３５】[0035]
【発明の効果】本発明は上記のように構成されているの
で、つぎのような効果を奏する。 （１） 微量の一酸化窒素と高濃度の酸素、さらに硫黄
酸化物をも含有するディーゼルエンジン排ガスを前段の
酸化触媒と後段の還元触媒で脱硝処理するに際し、前段
の酸化触媒に硫黄被毒を低く抑えるための第２成分を添
着させ、なおかつ、酸化触媒及び還元触媒の各々の操作
温度域を各々の触媒が最高活性を示す異なる温度域とす
ることにより、全体としての脱硝活性を大幅に向上させ
ることは勿論のこと、全体の脱硝性能の硫黄被毒耐性を
高めることができ、触媒の耐久性が大幅に改善される。 （２） 前段の酸化触媒と後段の還元触媒との組み合わ
せにおいて、還元触媒で昇温された高温の排ガスの熱を
利用して酸化触媒の加熱を行うことにより、エネルギー
の有効利用ができ、コスト的にも有利になる。 （３） 前段の酸化触媒と後段の還元触媒との組み合わ
せにおいて、還元触媒で昇温された高温の排ガスの熱を
利用して酸化触媒の加熱を行い、かつ、還元触媒に導入
する排ガスの温度を酸化触媒の出口温度より低温にする
ために、酸化触媒から出た高温の排ガスを入口ガスと熱
交換して冷却を行うことにより、外部熱源が不要とな
り、エネルギーの有効利用とコスト低減が実現できる。 （４） 低温、かつ高濃度の酸素、硫黄酸化物を含有す
るディーゼルエンジン排ガス中の窒素酸化物を、亜酸化
窒素の発生がほとんどなく、効率的に窒素ガスに変換す
ることができる。 （５） きわめて少ない量の炭化水素還元剤で効率的に
窒素ガスへの転換が行えるので、炭化水素還元剤の消費
量を極端に抑えることができる。As described above, the present invention has the following effects. (1) When denitrifying diesel engine exhaust gas containing trace amounts of nitric oxide, high-concentration oxygen, and sulfur oxides with a first-stage oxidation catalyst and a second-stage reduction catalyst, the first-stage oxidation catalyst is subjected to sulfur poisoning. The denitration activity as a whole is greatly improved by impregnating the second component to keep the temperature low and setting the operating temperature range of each of the oxidation catalyst and the reduction catalyst to a different temperature range where each catalyst shows the highest activity. Not only that, the sulfur poisoning resistance of the entire denitration performance can be increased, and the durability of the catalyst is greatly improved. (2) In the combination of the first-stage oxidation catalyst and the second-stage reduction catalyst, the heat of the high-temperature exhaust gas heated by the reduction catalyst is used to heat the oxidation catalyst, so that energy can be effectively used and cost is reduced. Is also advantageous. (3) In the combination of the first-stage oxidation catalyst and the second-stage reduction catalyst, the oxidation catalyst is heated by utilizing the heat of the high-temperature exhaust gas heated by the reduction catalyst, and the temperature of the exhaust gas introduced into the reduction catalyst. Cooling by exchanging the high-temperature exhaust gas from the oxidation catalyst with the inlet gas in order to make the temperature lower than the outlet temperature of the oxidation catalyst eliminates the need for an external heat source, realizing effective use of energy and cost reduction it can. (4) Nitrogen oxides in diesel engine exhaust gas containing low-temperature and high-concentration oxygen and sulfur oxides can be efficiently converted to nitrogen gas with almost no generation of nitrous oxide. (5) Since the conversion to nitrogen gas can be efficiently performed with a very small amount of the hydrocarbon reducing agent, the consumption of the hydrocarbon reducing agent can be extremely suppressed.
【図１】本発明のディーゼルエンジン排ガス中の窒素酸
化物除去方法を実施する装置を模式的に示す概念構成図
である。FIG. 1 is a conceptual configuration diagram schematically showing an apparatus for implementing a method for removing nitrogen oxides in diesel engine exhaust gas of the present invention.
【図２】本発明の実施の第１形態によるディーゼルエン
ジン排ガス中の窒素酸化物除去装置を示す概略構成説明
図である。FIG. 2 is a schematic configuration explanatory view showing a device for removing nitrogen oxides in exhaust gas of a diesel engine according to a first embodiment of the present invention.
【図３】本発明の実施の第２形態によるディーゼルエン
ジン排ガス中の窒素酸化物除去装置を示す概略構成説明
図である。FIG. 3 is a schematic structural explanatory view showing a device for removing nitrogen oxides from exhaust gas of a diesel engine according to a second embodiment of the present invention.
【図４】本発明の実施の第３形態によるディーゼルエン
ジン排ガス中の窒素酸化物除去装置を示す概略構成説明
図である。FIG. 4 is a schematic configuration explanatory view showing a device for removing nitrogen oxides from exhaust gas of a diesel engine according to a third embodiment of the present invention.
【図５】本発明の実施の第４形態によるディーゼルエン
ジン排ガス中の窒素酸化物除去装置を示す概略構成説明
図である。FIG. 5 is a schematic structural explanatory view showing a device for removing nitrogen oxides from diesel engine exhaust gas according to a fourth embodiment of the present invention.
【図６】本発明の実施の第５形態によるディーゼルエン
ジン排ガス中の窒素酸化物除去装置を示す概略構成説明
図である。FIG. 6 is a schematic structural explanatory view showing a device for removing nitrogen oxides from diesel engine exhaust gas according to a fifth embodiment of the present invention.
【図７】本発明の実施例で使用する試験装置を示す概略
構成説明図である。FIG. 7 is a schematic configuration explanatory view showing a test apparatus used in an embodiment of the present invention.
【図８】本発明の実施例におけるＳＯx被毒前、ＳＯx被
毒後、再生後での試験結果を示すグラフである。FIG. 8 is a graph showing test results before SOx poisoning, after SOx poisoning, and after regeneration in an example of the present invention.
【図９】比較例におけるＳＯx被毒前、ＳＯx被毒後、再
生後での試験結果を示すグラフである。FIG. 9 is a graph showing test results before, after and after regeneration of SOx in a comparative example.
【図１０】実施例及び比較例のＳＯx被毒後の経時変化
に伴うＮＯx除去率の変化を示すグラフである。FIG. 10 is a graph showing a change in the NOx removal rate according to a change over time after SOx poisoning in Examples and Comparative Examples.
１０、１４、２２、３０、５０、５６ 酸化触媒 １２、１８、２６、４４、４８、５８ 還元触媒 １６、２０、４２、５４ 熱交換器 ２４、２８ ジャケット構造の熱交換器 ３２、３６、４６、５２、６０、６２、６６ 排ガス流
路 ３４、３８ 三方切替コック ４０ バイパス流路 ６４ 外部熱源を用いない熱交換器 ６８、７０ 反応管10, 14, 22, 30, 50, 56 Oxidation catalyst 12, 18, 26, 44, 48, 58 Reduction catalyst 16, 20, 42, 54 Heat exchanger 24, 28 Heat exchanger 32, 36, 46 with jacket structure , 52, 60, 62, 66 Exhaust gas passage 34, 38 Three-way switching cock 40 Bypass passage 64 Heat exchanger without external heat source 68, 70 Reaction tube
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｆ０１Ｎ 3/10 Ｆ０１Ｎ 3/20 Ａ 3/20 3/28 ３０１Ｃ 3/28 ３０１ ３０１Ｄ ３０１Ｅ 3/36 Ａ 3/36 Ｂ０１Ｄ 53/36 １０２Ｇ (72)発明者 梶畠 賀敬 兵庫県明石市川崎町１番１号 川崎重工業 株式会社明石工場内 Ｆターム(参考） 3G091 AA02 AA04 AA18 AB02 AB04 BA01 BA05 BA14 CA01 CA07 CA18 GB05W GB06W GB07W HA09 HA10 4D048 AA06 AB01 AB02 AC02 AC10 BA11X BA15X BA30X BA31X BA32X BA33X BA34X BA37X BA38X BB01 BB02 CC32 CC47 CC48 CC51 4G069 AA02 AA03 AA08 BA07A BA07B BC12A BC18A BC18B BC32A BC33A BC36A BC67A BC68A BC68B BC70A BC71A BC72A BC74A BC75A BC75B CA03 CA07 CA08 CA13 DA06 EA02 EA19 ZA10B ZA11B ZA12B ZD01 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI theme coat ゛ (Reference) F01N 3/10 F01N 3/20 A 3/20 3/28 301C 3/28 301 301D 301E 3/36 A 3 / 36 B01D 53/36 102G (72) Inventor Kakei Hata 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. F-term in the Akashi Factory (reference) 3G091 AA02 AA04 AA18 AB02 AB04 BA01 BA05 BA14 CA01 CA07 CA18 GB05W GB06W GB07W HA09 HA10 4D048 AA06 AB01 AB02 AC02 AC10 BA11X BA15X BA30X BA31X BA32X BA33X BA34X BA37X BA38X BB01 BB02 CC32 CC47 CC48 CC51 4G069 AA02 AA03 AA08 BA07A BA07B BC12A BC18A BCBC BCBC BC BC CA13 DA06 EA02 EA19 ZA10B ZA11B ZA12B ZD01
Claims (19)
触媒と接触させて排ガス中の一酸化窒素を二酸化窒素に
酸化した後、この排ガスに後段の還元触媒の上流側で炭
化水素還元剤を添加し、ついで、排ガスを後段の還元触
媒と接触させて、前段で生成した二酸化窒素を含む窒素
酸化物を窒素ガスに転換する窒素酸化物除去方法であっ
て、前段の酸化触媒に硫黄被毒による触媒性能低下を抑
える第２成分を添着させることにより、全体の脱硝性能
の硫黄被毒耐性を高めるとともに、酸化触媒及び還元触
媒における各々の反応温度を、酸化触媒の方が還元触媒
よりも高くなるような各々の触媒が最高活性を示す異な
る温度域として操作することを特徴とするディーゼルエ
ンジン排ガス中の窒素酸化物除去方法。1. After exhaust gas of a diesel engine is brought into contact with an oxidation catalyst of a preceding stage to oxidize nitrogen monoxide in the exhaust gas to nitrogen dioxide, a hydrocarbon reducing agent is added to the exhaust gas on the upstream side of a reduction catalyst of a subsequent stage, Then, the exhaust gas is brought into contact with a subsequent reduction catalyst to convert nitrogen oxides containing nitrogen dioxide generated in the previous stage into nitrogen gas. By impregnating the second component for suppressing the decrease, the sulfur poisoning resistance of the entire denitration performance is increased, and the respective reaction temperatures of the oxidation catalyst and the reduction catalyst are set to be higher in the oxidation catalyst than in the reduction catalyst. A method for removing nitrogen oxides from diesel engine exhaust gas, wherein each catalyst is operated in a different temperature range where the catalyst exhibits the highest activity.
ム、パラジウム、ルテニウム及びイリジウムからなる群
より選ばれる貴金属をイオン交換により担持したゼオラ
イトを用い、酸化触媒に添着させる第２成分として、ニ
ッケル、コバルト及びストロンチウムからなる群より選
ばれる金属を用いる請求項１記載のディーゼルエンジン
排ガス中の窒素酸化物除去方法。2. An oxidation catalyst comprising zeolite carrying a noble metal selected from the group consisting of platinum, gold, silver, rhodium, palladium, ruthenium and iridium by ion exchange, and nickel as a second component to be impregnated in the oxidation catalyst. 2. The method for removing nitrogen oxides from diesel engine exhaust gas according to claim 1, wherein a metal selected from the group consisting of, cobalt and strontium is used.
ム、銀、カドミウムからなる群より選ばれる金属をイオ
ン交換により担持したゼオライトを用いる請求項１又は
２記載のディーゼルエンジン排ガス中の窒素酸化物除去
方法。3. The method for removing nitrogen oxides from diesel engine exhaust gas according to claim 1, wherein a zeolite carrying a metal selected from the group consisting of indium, palladium, silver and cadmium by ion exchange is used as the reduction catalyst.
００℃の範囲とし、還元触媒における反応温度を２００
〜４００℃の範囲とする請求項１、２又は３記載のディ
ーゼルエンジン排ガス中の窒素酸化物除去方法。4. The reaction temperature in the oxidation catalyst is 400 to 5
And the reaction temperature in the reduction catalyst was 200
The method for removing nitrogen oxides from diesel engine exhaust gas according to claim 1, 2 or 3, wherein the temperature is in the range of -400 ° C.
ン、プロパン、ヘキサン、エチレン、プロピレン、ヘキ
セン、ガソリン、灯油、軽油、Ａ重油及びＣ重油のいず
れかを用いる請求項１〜４のいずれかに記載のディーゼ
ルエンジン排ガス中の窒素酸化物除去方法。5. The method according to claim 1, wherein any one of methane, ethane, propane, hexane, ethylene, propylene, hexene, gasoline, kerosene, light oil, heavy fuel oil A and heavy fuel oil C is used as the hydrocarbon reducing agent. The method for removing nitrogen oxides from exhaust gas of a diesel engine as described above.
け、酸化触媒と還元触媒との間に冷却用熱交換器を設け
て、酸化触媒及び還元触媒における各々の反応温度を、
酸化触媒の方が還元触媒よりも高くなるような各々の触
媒が最高活性を示す異なる温度域として操作する請求項
１〜５のいずれかに記載のディーゼルエンジン排ガス中
の窒素酸化物除去方法。6. A heat exchanger for heating is provided on the upstream side of the oxidation catalyst, and a heat exchanger for cooling is provided between the oxidation catalyst and the reduction catalyst.
The method for removing nitrogen oxides in diesel engine exhaust gas according to any one of claims 1 to 5, wherein each of the catalysts is operated in a different temperature range in which the oxidation catalyst is higher than the reduction catalyst so that each catalyst exhibits the highest activity.
元触媒の充填層を周囲から冷却して、酸化触媒及び還元
触媒における各々の反応温度を、酸化触媒の方が還元触
媒よりも高くなるような各々の触媒が最高活性を示す異
なる温度域として操作する請求項１〜５のいずれかに記
載のディーゼルエンジン排ガス中の窒素酸化物除去方
法。7. The packed bed of the oxidation catalyst is heated from the surroundings, and the packed bed of the reduction catalyst is cooled from the surroundings, so that the respective reaction temperatures of the oxidation catalyst and the reduction catalyst are higher in the oxidation catalyst than in the reduction catalyst. The method for removing nitrogen oxides from diesel engine exhaust gas according to any one of claims 1 to 5, wherein each of the catalysts operates in a different temperature range where the catalyst exhibits the highest activity.
れる流路に冷却用熱交換器を設け、かつ、還元触媒から
出た排ガスの流路内に酸化触媒を設置して、還元触媒で
昇温された高温の排ガスの熱を利用して酸化触媒の加熱
を行う請求項１〜５のいずれかに記載のディーゼルエン
ジン排ガス中の窒素酸化物除去方法。8. A cooling heat exchanger is provided in a flow path through which exhaust gas discharged from the oxidation catalyst flows to the reduction catalyst, and an oxidation catalyst is provided in a flow path of exhaust gas discharged from the reduction catalyst. The method for removing nitrogen oxides in diesel engine exhaust gas according to any one of claims 1 to 5, wherein the oxidation catalyst is heated by using the heat of the high-temperature exhaust gas whose temperature has been raised.
触媒を設置して、還元触媒で昇温された高温の排ガスの
熱を利用して酸化触媒の加熱を行うとともに、酸化触媒
から出た排ガスが還元触媒へ流れる流路に熱交換器を設
置し、該熱交換器で酸化触媒に導入前の排ガスと熱交換
して、酸化触媒から出た高温の排ガスの冷却を行い、還
元触媒に導入する排ガスの温度を酸化触媒の出口温度よ
り低温にする請求項１〜５のいずれかに記載のディーゼ
ルエンジン排ガス中の窒素酸化物除去方法。9. An oxidation catalyst is provided in a flow path of exhaust gas discharged from the reduction catalyst, and the heat of the high temperature exhaust gas heated by the reduction catalyst is used to heat the oxidation catalyst. A heat exchanger is installed in the flow path where the discharged exhaust gas flows to the reduction catalyst, and the heat exchanger exchanges heat with the exhaust gas before being introduced into the oxidation catalyst, thereby cooling the high-temperature exhaust gas discharged from the oxidation catalyst and reducing the exhaust gas. The method for removing nitrogen oxides in diesel engine exhaust gas according to any one of claims 1 to 5, wherein the temperature of the exhaust gas introduced into the catalyst is lower than the outlet temperature of the oxidation catalyst.
化触媒と接触させて排ガス中の一酸化窒素を二酸化窒素
に酸化した後、この排ガスに後段の還元触媒の上流側で
炭化水素還元剤を添加し、ついで、排ガスを後段の還元
触媒と接触させて生成した二酸化窒素を含む窒素酸化物
を窒素ガスに転換する窒素酸化物除去方法であって、酸
化触媒から出た排ガスが還元触媒へ流れる流路に冷却用
熱交換器を設け、かつ、還元触媒から出た排ガスの流路
内に酸化触媒を設置して、還元触媒で昇温された高温の
排ガスの熱を利用して酸化触媒の加熱を行うことを特徴
とするディーゼルエンジン排ガス中の窒素酸化物除去方
法。10. A diesel engine exhaust gas is brought into contact with a preceding oxidation catalyst to oxidize nitrogen monoxide in the exhaust gas to nitrogen dioxide, and then a hydrocarbon reducing agent is added to the exhaust gas upstream of the latter reduction catalyst. Next, a method for removing nitrogen oxides containing nitrogen dioxide generated by contacting the exhaust gas with a subsequent reduction catalyst into nitrogen gas, wherein the exhaust gas discharged from the oxidation catalyst flows through a flow path to the reduction catalyst A cooling heat exchanger is provided, and an oxidation catalyst is installed in the flow path of the exhaust gas discharged from the reduction catalyst, and the oxidation catalyst is heated using heat of the high-temperature exhaust gas heated by the reduction catalyst. A method for removing nitrogen oxides from exhaust gas of a diesel engine.
化触媒と接触させて排ガス中の一酸化窒素を二酸化窒素
に酸化した後、この排ガスに後段の還元触媒の上流側で
炭化水素還元剤を添加し、ついで、排ガスを後段の還元
触媒と接触させて生成した二酸化窒素を含む窒素酸化物
を窒素ガスに転換する窒素酸化物除去方法であって、還
元触媒から出た排ガスの流路内に酸化触媒を設置して、
還元触媒で昇温された高温の排ガスの熱を利用して酸化
触媒の加熱を行うとともに、酸化触媒から出た排ガスが
還元触媒へ流れる流路に熱交換器を設置し、該熱交換器
で酸化触媒に導入前の排ガスと熱交換して、酸化触媒か
ら出た高温の排ガスの冷却を行い、還元触媒に導入する
排ガスの温度を酸化触媒の出口温度より低温にすること
を特徴とするディーゼルエンジン排ガス中の窒素酸化物
除去方法。11. A diesel engine exhaust gas is brought into contact with a preceding oxidation catalyst to oxidize nitrogen monoxide in the exhaust gas to nitrogen dioxide, and then a hydrocarbon reducing agent is added to the exhaust gas upstream of the latter reduction catalyst. Next, a method for removing nitrogen oxides containing nitrogen dioxide produced by contacting the exhaust gas with a subsequent reduction catalyst to nitrogen gas, wherein an oxidation catalyst is placed in a flow path of the exhaust gas discharged from the reduction catalyst. Install it,
The oxidation catalyst is heated by using the heat of the high-temperature exhaust gas heated by the reduction catalyst, and a heat exchanger is installed in a flow path in which the exhaust gas flowing out of the oxidation catalyst flows to the reduction catalyst. Diesel characterized by exchanging heat with exhaust gas before introduction into the oxidation catalyst to cool the high-temperature exhaust gas discharged from the oxidation catalyst, and to make the temperature of the exhaust gas introduced into the reduction catalyst lower than the exit temperature of the oxidation catalyst. A method for removing nitrogen oxides from engine exhaust gas.
窒素を二酸化窒素に酸化するための酸化触媒を充填し、
かつ、酸化触媒に全体の脱硝性能の硫黄被毒耐性を高め
るための第２成分を添着させた酸化反応手段と、酸化反
応手段の上流に設けられた酸化触媒が最高活性を示す４
００〜５００℃の温度域に温度調整するための加熱用熱
交換器と、酸化反応手段の下流に設けられた排ガスに炭
化水素還元剤を添加するための還元剤添加手段と、還元
剤添加手段の下流に設けられた排ガス中の二酸化窒素を
含む窒素酸化物を窒素ガスに還元するための還元触媒を
充填した還元反応手段と、還元反応手段の上流に設けら
れた還元触媒が最高活性を示す２００〜４００℃の温度
域に温度調整するための冷却用熱交換器とを備えたこと
を特徴とするディーゼルエンジン排ガス中の窒素酸化物
除去装置。12. An oxidation catalyst for oxidizing nitrogen monoxide in a diesel engine exhaust gas to nitrogen dioxide is filled,
Further, the oxidation reaction means in which a second component for improving the sulfur poisoning resistance of the entire denitration performance is attached to the oxidation catalyst, and the oxidation catalyst provided upstream of the oxidation reaction means exhibits the highest activity.
A heating heat exchanger for adjusting the temperature to a temperature range of from 00 to 500 ° C., a reducing agent adding unit for adding a hydrocarbon reducing agent to exhaust gas provided downstream of the oxidation reaction unit, and a reducing agent adding unit Reduction reaction means provided with a reduction catalyst for reducing nitrogen oxides containing nitrogen dioxide in exhaust gas to nitrogen gas provided downstream of the exhaust gas, and a reduction catalyst provided upstream of the reduction reaction means exhibit the highest activity An apparatus for removing nitrogen oxides from exhaust gas of a diesel engine, comprising: a cooling heat exchanger for adjusting the temperature to a temperature range of 200 to 400 ° C.
窒素を二酸化窒素に酸化するための酸化触媒を充填し、
かつ、酸化触媒に全体の脱硝性能の硫黄被毒耐性を高め
るための第２成分を添着させた酸化反応手段と、酸化反
応手段に装着された酸化触媒が最高活性を示す４００〜
５００℃の温度域に温度調整するためのジャケット構造
の加熱手段と、酸化反応手段の下流に設けられた排ガス
に炭化水素還元剤を添加するための還元剤添加手段と、
還元剤添加手段の下流に設けられた排ガス中の二酸化窒
素を含む窒素酸化物を窒素ガスに還元するための還元触
媒を充填した還元反応手段と、還元反応手段に装着され
た還元触媒が最高活性を示す２００〜４００℃の温度域
に温度調整するためのジャケット構造の冷却手段とを備
えたことを特徴とするディーゼルエンジン排ガス中の窒
素酸化物除去装置。13. An oxidation catalyst for oxidizing nitrogen monoxide in diesel engine exhaust gas to nitrogen dioxide is filled,
Further, the oxidation reaction means in which a second component for increasing the sulfur poisoning resistance of the entire denitration performance is attached to the oxidation catalyst, and the oxidation catalyst mounted on the oxidation reaction means has a maximum activity of 400 to
Heating means having a jacket structure for adjusting the temperature to a temperature range of 500 ° C .; reducing agent adding means for adding a hydrocarbon reducing agent to exhaust gas provided downstream of the oxidation reaction means;
The reduction reaction means provided downstream of the reducing agent addition means and filled with a reduction catalyst for reducing nitrogen oxides containing nitrogen dioxide in the exhaust gas to nitrogen gas, and the reduction catalyst mounted on the reduction reaction means have the highest activity. A cooling device having a jacket structure for adjusting the temperature to a temperature range of 200 to 400 ° C., the nitrogen oxides being removed from exhaust gas of a diesel engine.
窒素を二酸化窒素に酸化するための酸化触媒を充填した
酸化反応手段と、酸化反応手段の下流の排ガス流路に設
けられた排ガスに炭化水素還元剤を添加するための還元
剤添加手段と、還元剤添加手段の下流の排ガス流路に設
けられた排ガス中の二酸化窒素を含む窒素酸化物を窒素
ガスに還元するための還元触媒を充填した還元反応手段
と、酸化反応手段と還元反応手段との間の排ガス流路に
設けられた冷却用熱交換器とを備え、酸化触媒を充填し
た酸化反応手段が還元反応手段の下流の排ガス流路内に
配置されており、還元触媒で昇温された高温の排ガスの
熱を利用して酸化触媒の加熱が行われるようにしたこと
を特徴とするディーゼルエンジン排ガス中の窒素酸化物
除去装置。14. An oxidation reaction means filled with an oxidation catalyst for oxidizing nitrogen monoxide in a diesel engine exhaust gas to nitrogen dioxide, and a hydrocarbon reducing agent provided in an exhaust gas provided in an exhaust gas flow path downstream of the oxidation reaction means. Reducing agent adding means for adding nitrogen, and a reduction reaction filled with a reducing catalyst for reducing nitrogen oxides containing nitrogen dioxide in exhaust gas provided in an exhaust gas flow path downstream of the reducing agent adding means to nitrogen gas Means, and a cooling heat exchanger provided in the exhaust gas flow path between the oxidation reaction means and the reduction reaction means, wherein the oxidation reaction means filled with the oxidation catalyst is in the exhaust gas flow path downstream of the reduction reaction means. An apparatus for removing nitrogen oxides from exhaust gas of a diesel engine, wherein the apparatus is disposed and uses heat of a high-temperature exhaust gas heated by a reduction catalyst to heat an oxidation catalyst.
窒素を二酸化窒素に酸化するための酸化触媒を充填した
酸化反応手段と、酸化反応手段の下流の排ガス流路に設
けられた排ガスに炭化水素還元剤を添加するための還元
剤添加手段と、還元剤添加手段の下流の排ガス流路に設
けられた排ガス中の二酸化窒素を含む窒素酸化物を窒素
ガスに還元するための還元触媒を充填した還元反応手段
とを備え、酸化触媒を充填した酸化反応手段が還元反応
手段の下流の排ガス流路内に配置されており、還元触媒
で昇温された高温の排ガスの熱を利用して酸化触媒の加
熱が行われるようにし、かつ、酸化反応手段と還元反応
手段との間の排ガス流路に熱交換器が設けられ、該熱交
換器が酸化反応手段の上流の排ガス流路に設置されるよ
うにして、酸化触媒から出た高温の排ガスが入口ガスと
熱交換して冷却され、還元触媒に導入する排ガスの温度
が酸化触媒の出口温度より低温になるようにしたことを
特徴とするディーゼルエンジン排ガス中の窒素酸化物除
去装置。15. An oxidation reaction means filled with an oxidation catalyst for oxidizing nitrogen monoxide in a diesel engine exhaust gas to nitrogen dioxide, and a hydrocarbon reducing agent provided in an exhaust gas provided in an exhaust gas flow path downstream of the oxidation reaction means. Reducing agent adding means for adding nitrogen, and a reduction reaction filled with a reducing catalyst for reducing nitrogen oxides containing nitrogen dioxide in exhaust gas provided in an exhaust gas flow path downstream of the reducing agent adding means to nitrogen gas And an oxidation reaction means filled with the oxidation catalyst is disposed in the exhaust gas flow path downstream of the reduction reaction means, and heats the oxidation catalyst by utilizing heat of the high-temperature exhaust gas heated by the reduction catalyst. Is performed, and a heat exchanger is provided in an exhaust gas flow path between the oxidation reaction means and the reduction reaction means, and the heat exchanger is provided in an exhaust gas flow path upstream of the oxidation reaction means. And oxidation catalyst Nitrogen gas in diesel engine exhaust gas, characterized in that the high-temperature exhaust gas discharged from the exhaust gas is cooled by exchanging heat with the inlet gas, so that the temperature of the exhaust gas introduced into the reduction catalyst is lower than the outlet temperature of the oxidation catalyst. Object removal device.
酸化触媒に全体の脱硝性能の硫黄被毒耐性を高めるため
の第２成分を添着させたものである請求項１４又は１５
記載のディーゼルエンジン排ガス中の窒素酸化物除去装
置。16. The oxidation catalyst filled in the oxidation reaction means,
16. The oxidation catalyst to which a second component for increasing the sulfur poisoning resistance of the entire denitration performance is impregnated.
A device for removing nitrogen oxides from exhaust gas of a diesel engine as described in the above.
白金、金、銀、ロジウム、パラジウム、ルテニウム及び
イリジウムからなる群より選ばれる貴金属をイオン交換
により担持したゼオライトであり、第２成分が、ニッケ
ル、コバルト及びストロンチウムからなる群より選ばれ
る金属である請求項１２、１３又は１６記載のディーゼ
ルエンジン排ガス中の窒素酸化物除去装置。17. The oxidation catalyst filled in the oxidation reaction means,
A zeolite carrying a noble metal selected from the group consisting of platinum, gold, silver, rhodium, palladium, ruthenium and iridium by ion exchange, and the second component is a metal selected from the group consisting of nickel, cobalt and strontium. Item 17. An apparatus for removing nitrogen oxides from diesel engine exhaust gas according to item 12, 13 or 16.
インジウム、パラジウム、銀、カドミウムからなる群よ
り選ばれる金属をイオン交換により担持したゼオライト
である請求項１２〜１７のいずれかに記載のディーゼル
エンジン排ガス中の窒素酸化物除去装置。18. The reduction catalyst filled in the reduction reaction means,
18. The apparatus for removing nitrogen oxides from diesel engine exhaust gas according to claim 12, wherein the zeolite is a zeolite carrying a metal selected from the group consisting of indium, palladium, silver, and cadmium by ion exchange.
れる炭化水素還元剤が、メタン、エタン、プロパン、ヘ
キサン、エチレン、プロピレン、ヘキセン、ガソリン、
灯油、軽油、Ａ重油及びＣ重油のいずれかである請求項
１２〜１８のいずれかに記載のディーゼルエンジン排ガ
ス中の窒素酸化物除去装置。19. The hydrocarbon reducing agent added to the exhaust gas by the reducing agent adding means is methane, ethane, propane, hexane, ethylene, propylene, hexene, gasoline,
The apparatus for removing nitrogen oxides in diesel engine exhaust gas according to any one of claims 12 to 18, wherein the apparatus is any of kerosene, light oil, A heavy oil, and C heavy oil.
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|---|---|---|---|
| JP2001150614A JP4685266B2 (en) | 2001-05-21 | 2001-05-21 | Method and apparatus for removing nitrogen oxides in diesel engine exhaust gas |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001150614A JP4685266B2 (en) | 2001-05-21 | 2001-05-21 | Method and apparatus for removing nitrogen oxides in diesel engine exhaust gas |
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| Publication Number | Publication Date |
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| JP2002349248A true JP2002349248A (en) | 2002-12-04 |
| JP4685266B2 JP4685266B2 (en) | 2011-05-18 |
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| JP2001150614A Expired - Fee Related JP4685266B2 (en) | 2001-05-21 | 2001-05-21 | Method and apparatus for removing nitrogen oxides in diesel engine exhaust gas |
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| KR101903406B1 (en) * | 2015-02-16 | 2018-11-07 | 삼성중공업 주식회사 | Device for Purifying Exhaust and Vessel having the Same |
| CN113750730A (en) * | 2021-09-24 | 2021-12-07 | 中天电子材料有限公司 | Chemical method polyimide film production waste gas treatment device and application thereof |
| CN115414780A (en) * | 2022-09-05 | 2022-12-02 | 中国矿业大学 | High concentration NO x Flue gas denitration system and control method |
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|---|---|
| JP4685266B2 (en) | 2011-05-18 |
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