JP2649217B2 - Exhaust gas purifying material and exhaust gas purifying method - Google Patents
Exhaust gas purifying material and exhaust gas purifying methodInfo
- Publication number
- JP2649217B2 JP2649217B2 JP6301478A JP30147894A JP2649217B2 JP 2649217 B2 JP2649217 B2 JP 2649217B2 JP 6301478 A JP6301478 A JP 6301478A JP 30147894 A JP30147894 A JP 30147894A JP 2649217 B2 JP2649217 B2 JP 2649217B2
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- catalyst
- purifying material
- silver
- gas purifying
- 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.)
- Expired - Lifetime
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- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は窒素酸化物と過剰の酸素
を含む燃焼排ガスから、窒素酸化物を効果的に還元除去
することのできる排ガス浄化材及びそれを用いた浄化方
法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying material capable of effectively reducing and removing nitrogen oxides from a combustion exhaust gas containing nitrogen oxides and excess oxygen, and a purification method using the same.
【0002】[0002]
【従来の技術及び発明が解決しようとする課題】自動車
用エンジン等の内燃機関や、工場等に設置された燃焼機
器、家庭用ファンヒーターなどから排出される各種の燃
焼排ガス中には、過剰の酸素とともに一酸化窒素、二酸
化窒素等の窒素酸化物が含まれている。ここで、「過剰
の酸素を含む」とは、その排ガス中に含まれる一酸化炭
素、水素、炭化水素等の未燃焼成分を燃焼するのに必要
な理論酸素量より多い酸素を含むことを意味する。ま
た、以下における窒素酸化物とは一酸化窒素及び/又は
二酸化窒素を指す。2. Description of the Related Art Excessive combustion exhaust gas discharged from internal combustion engines such as automobile engines, combustion equipment installed in factories, household fan heaters, and the like is excessive. It contains nitrogen oxides such as nitric oxide and nitrogen dioxide together with oxygen. Here, "containing excess oxygen" means that the exhaust gas contains more oxygen than the theoretical amount of oxygen necessary to burn unburned components such as carbon monoxide, hydrogen, and hydrocarbons. I do. In the following, nitrogen oxide refers to nitric oxide and / or nitrogen dioxide.
【0003】この窒素酸化物は酸性雨の原因の一つとさ
れ、環境上の大きな問題となっている。そのため、各種
燃焼機器が排出する排ガス中の窒素酸化物を除去するさ
まざまな方法が検討されている。[0003] This nitrogen oxide is one of the causes of acid rain and is a major environmental problem. Therefore, various methods for removing nitrogen oxides in exhaust gas discharged from various combustion equipments are being studied.
【0004】過剰の酸素を含む燃焼排ガスから窒素酸化
物を除去する方法として、特に大規模な固定燃焼装置
(工場等の大型燃焼機等)に対しては、アンモニアを用
いる選択的接触還元法が実用化されている。[0004] As a method for removing nitrogen oxides from a combustion exhaust gas containing excess oxygen, a selective catalytic reduction method using ammonia is used particularly for a large-scale fixed combustion device (a large-scale combustor in a factory or the like). Has been put to practical use.
【0005】しかしながら、この方法においては、窒素
酸化物の還元剤として用いるアンモニアが高価であるこ
と、またアンモニアは毒性を有すること、そのために未
反応のアンモニアが排出しないように排ガス中の窒素酸
化物濃度を計測しながらアンモニア注入量を制御しなけ
ればならないこと、一般に装置が大型となること等の問
題点がある。However, in this method, ammonia used as a reducing agent for nitrogen oxides is expensive, and ammonia is toxic. Therefore, the nitrogen oxides in the exhaust gas must be removed so that unreacted ammonia is not discharged. There are problems that the amount of injected ammonia must be controlled while measuring the concentration, and that the apparatus generally becomes large.
【0006】また、別な方法として、水素、一酸化炭
素、炭化水素等のガスを還元剤として用い、窒素酸化物
を還元する非選択的接触還元法があるが、この方法で
は、効果的な窒素酸化物の低減除去を実行するためには
排ガス中の酸素との理論反応量以上の還元剤を添加しな
ければならず、還元剤を多量に消費する欠点がある。こ
のため非選択的接触還元法は、実際上は、理論空燃比付
近で燃焼した残存酸素濃度の低い排ガスに対してのみ有
効となり、汎用性に乏しく実際的でない。As another method, there is a non-selective catalytic reduction method in which a nitrogen oxide is reduced by using a gas such as hydrogen, carbon monoxide, or a hydrocarbon as a reducing agent. In order to reduce and remove nitrogen oxides, it is necessary to add a reducing agent in an amount equal to or more than a theoretical reaction amount with oxygen in exhaust gas, and there is a disadvantage that a large amount of the reducing agent is consumed. For this reason, the non-selective catalytic reduction method is practically effective only for exhaust gas having a low residual oxygen concentration burned near the stoichiometric air-fuel ratio, and is not practical because of poor versatility.
【0007】そこで、ゼオライト又はそれに遷移金属を
担持した触媒を用いて、排ガス中の酸素との理論反応量
以下の還元剤を添加して窒素酸化物を除去する方法が提
案された(たとえば、特開昭63-100919 号、同63-28372
7 号、特開平1-130735号等)。In view of the above, a method has been proposed for removing nitrogen oxides by using a zeolite or a catalyst supporting a transition metal on the zeolite and adding a reducing agent having a theoretical reaction amount or less with oxygen in the exhaust gas (for example, Japanese Patent Application Laid-Open Publication No. H11-163873). No.63-100919, 63-28372
No. 7, JP-A No. 1-130735).
【0008】しかしながら、これらの方法では、効果的
な窒素酸化物の除去が狭い温度領域でしか得られず、ま
た、水分を含むような排ガスでは、窒素酸化物の除去率
が著しく低下する。つまり、10%程度の水分を含み、
運転条件によって温度変化の大きい車等からの排ガスに
対して、窒素酸化物の効果的除去は困難である。However, in these methods, effective removal of nitrogen oxides can be obtained only in a narrow temperature range, and in an exhaust gas containing water, the removal rate of nitrogen oxides is significantly reduced. In other words, it contains about 10% water,
It is difficult to effectively remove nitrogen oxides from exhaust gas from a vehicle or the like whose temperature changes greatly depending on operating conditions.
【0009】したがって、本発明の目的は、固定燃焼装
置および酸素過剰条件で燃焼するガソリンエンジン、デ
ィーゼルエンジン等からの燃焼排ガスのように、窒素酸
化物や、一酸化炭素、水素、炭化水素等の未燃焼分に対
する理論反応量以上の酸素を含有する燃焼排ガスから、
効率良く窒素酸化物を還元除去することができる排ガス
浄化材及び排ガス浄化方法を提供することである。Accordingly, it is an object of the present invention to provide a method for producing nitrogen oxides, carbon monoxide, hydrogen, hydrocarbons and the like, such as combustion exhaust gas from a fixed combustion device and a gasoline engine, a diesel engine or the like, which burns under oxygen excess conditions. From combustion exhaust gas containing more than the theoretical reaction amount for unburned components,
An object of the present invention is to provide an exhaust gas purifying material and an exhaust gas purifying method capable of efficiently reducing and removing nitrogen oxides.
【0010】[0010]
【課題を解決するための手段】上記課題に鑑み鋭意研究
の結果、本発明者は、多孔質無機酸化物に銀成分を担持
してなる触媒上で、エタノールなどの有機化合物が、酸
素及び窒素酸化物を含む排ガスと反応し、窒素酸化物を
窒素ガスに還元するとともに、副生成物として亜硝酸エ
ステル、アンモニアなどの含窒素化合物やアルデヒドを
生成していることを見出した。これらの含窒素化合物を
窒素まで還元できる銅系又は銅、W系成分担持してなる
触媒と白金系成分を担持してなる触媒とを混合し、銀系
触媒と上記混合触媒とを組み合わせて形成される排ガス
浄化材を用い、排ガス中に炭化水素と炭素数2以上の含
酸素有機化合物のいずれか又はそれらを含む燃料を添加
し、特定の温度及び空間速度で上記の浄化材に排ガスを
接触させれば、広い温度領域で窒素酸化物を効果的に除
去することができることを発見し、本発明を完成した。Means for Solving the Problems In view of the above problems, as a result of intensive studies, the present inventor has found that an organic compound such as ethanol is converted to oxygen and nitrogen on a catalyst comprising a porous inorganic oxide carrying a silver component. It has been found that it reacts with exhaust gas containing oxides to reduce nitrogen oxides to nitrogen gas and to generate nitrogen-containing compounds such as nitrites and ammonia and aldehydes as by-products. A catalyst comprising a copper-based or copper-based component capable of reducing these nitrogen-containing compounds to nitrogen and a catalyst comprising a platinum-based component are mixed, and formed by combining a silver-based catalyst and the above mixed catalyst. Using a waste gas purifying material to be used, add one of hydrocarbons and oxygen-containing organic compounds having 2 or more carbon atoms or a fuel containing them into the flue gas, and contact the flue gas with the purifying material at a specific temperature and space velocity. By doing so, they discovered that nitrogen oxides could be effectively removed in a wide temperature range, and completed the present invention.
【0011】すなわち、本発明の第一の排ガス浄化材は
多孔質の無機酸化物に活性種として銀及び/又は銀化合
物、又はそれらの混合物0.2〜15重量%(銀元素換
算値)を担持してなる第一の触媒と、多孔質の無機酸化
物に活性種として銅の酸化物及び/又は硫酸塩0.2〜
30重量%(銅元素換算値)を担持してなる第二の触媒
と、多孔質の無機酸化物に活性種としてPt、Pd、Ru、R
h、Ir及びAuからなる群より選ばれた少なくとも1種の
元素0.01〜5重量%(金属元素換算値)を担持して
なる第三の触媒とからなり、前記第一の触媒が排ガス流
入側に面し、前記第二の触媒と前記第三の触媒とを混合
してなる混合触媒が排ガス流出側に面することを特徴と
する。That is, the first exhaust gas purifying material of the present invention comprises a porous inorganic oxide containing 0.2 to 15% by weight (in terms of silver element) of silver and / or a silver compound or a mixture thereof as active species. A first catalyst supported on the porous inorganic oxide, copper oxide and / or sulfate as an active species of 0.2 to 0.2 to
A second catalyst supporting 30% by weight (in terms of a copper element) and Pt, Pd, Ru, and R as active species on a porous inorganic oxide;
a third catalyst supporting at least one element selected from the group consisting of h, Ir, and Au in an amount of 0.01 to 5% by weight (in terms of a metal element), wherein the first catalyst is an exhaust gas. A mixed catalyst formed by mixing the second catalyst and the third catalyst facing the inflow side faces the exhaust gas outflow side.
【0012】また、本発明の第二の排ガス浄化材は多孔
質の無機酸化物に活性種として銀及び/又は銀化合物、
又はそれらの混合物0.2〜15重量%(銀元素換算
値)を担持してなる第一の触媒と、多孔質の無機酸化物
に活性種として銅の酸化物及び/又は硫酸塩0.2〜3
0重量%(銅元素換算値)と、W、V、Moからなる群
より選ばれた少なくとも一種の元素の酸化物又は硫酸塩
30重量%以下(金属元素換算値)とを担持してなる第
二の触媒と、多孔質の無機酸化物に活性種としてPt、P
d、Ru、Rh、Ir及びAuからなる群より選ばれた少なくと
も1種の元素0.01〜5重量%(金属元素換算値)を
担持してなる第三の触媒とからなり、前記第一の触媒が
排ガス流入側に面し、前記第二の触媒と前記第三の触媒
とを混合してなる混合触媒が排ガス流出側に面すること
を特徴とする。Further, the second exhaust gas purifying material of the present invention comprises a porous inorganic oxide containing silver and / or a silver compound as an active species;
Alternatively, a first catalyst supporting 0.2 to 15% by weight (in terms of silver element) of a mixture thereof, and a porous inorganic oxide containing copper oxide and / or sulfate 0.2% as an active species. ~ 3
0% by weight (converted to a copper element) and 30% by weight or less (converted to a metal element) of an oxide or sulfate of at least one element selected from the group consisting of W, V, and Mo. Pt, P as active species on the second catalyst and the porous inorganic oxide
d, a third catalyst supporting at least one element selected from the group consisting of Ru, Rh, Ir and Au in an amount of 0.01 to 5% by weight (in terms of a metal element); Wherein the mixed catalyst formed by mixing the second catalyst and the third catalyst faces the exhaust gas outflow side.
【0013】さらに、窒素酸化物と、共存する未燃焼成
分に対する理論反応量より多い酸素とを含む燃焼排ガス
から窒素酸化物を還元除去する本発明の排ガス浄化方法
は、上記排ガス浄化材を排ガス導管の途中に設置し、前
記浄化材の上流側で炭化水素及び/又は含酸素有機化合
物を添加した排ガスを、150〜600℃において前記
浄化材に接触させ、もって前記排ガス中の炭化水素及び
/又は含酸素有機化合物との反応により前記窒素酸化物
を除去することを特徴とする。Further, the exhaust gas purifying method of the present invention for reducing and removing nitrogen oxides from a combustion exhaust gas containing nitrogen oxides and oxygen in excess of the theoretical reaction amount for coexisting unburned components, comprises: And the exhaust gas to which hydrocarbons and / or oxygen-containing organic compounds are added on the upstream side of the purification material is brought into contact with the purification material at 150 to 600 ° C., whereby the hydrocarbons and / or The nitrogen oxide is removed by a reaction with an oxygen-containing organic compound.
【0014】以下、本発明を詳細に説明する。本発明の
第一の排ガス浄化材では、多孔質の無機酸化物に活性種
として銀及び/又は銀化合物、又はそれらの混合物0.
2〜15重量%(銀元素換算値)を担持してなる第一の
触媒と、多孔質の無機酸化物に活性種として銅の酸化物
及び/又は硫酸塩0.2〜30重量%(銅元素換算値)
を担持してなる第二の触媒と、多孔質の無機酸化物に活
性種としてPt、Pd、Ru、Rh、Ir及びAuからなる群より選
ばれた少なくとも1種の元素0.01〜5重量%(金属
元素換算値)を担持してなる第三の触媒とからなる排ガ
ス浄化材を排ガス導管中に設置し、浄化材の設置位置よ
り上流側で炭化水素と炭素数2以上の含酸素有機化合物
のいずれか又はそれを含む燃料を添加した排ガスをこの
浄化材に接触させて、排ガス中の窒素酸化物を還元除去
する。排ガス浄化材は、前記第一の触媒が排ガス流入側
に面し、前記第二の触媒と前記第三の触媒とを混合して
なる混合触媒が排ガス流出側に面するように配置する。
このように配置することによって、広い排ガス温度領域
で窒素酸化物を効果的に還元除去することができる。Hereinafter, the present invention will be described in detail. In the first exhaust gas purifying material of the present invention, silver and / or a silver compound or a mixture thereof is used as an active species in a porous inorganic oxide.
A first catalyst supporting 2 to 15% by weight (in terms of silver element), and a porous inorganic oxide containing copper oxide and / or sulfate as an active species 0.2 to 30% by weight (copper Element conversion value)
And at least one element selected from the group consisting of Pt, Pd, Ru, Rh, Ir, and Au as active species in the porous inorganic oxide, 0.01 to 5% by weight. % (In terms of metal element), an exhaust gas purifying material comprising a third catalyst is installed in an exhaust gas conduit, and a hydrocarbon and an oxygen-containing organic compound having 2 or more carbon atoms are located upstream of the purifying material installation position. An exhaust gas to which any of the compounds or a fuel containing the compound is added is brought into contact with the purifying material to reduce and remove nitrogen oxides in the exhaust gas. The exhaust gas purifying material is disposed such that the first catalyst faces the exhaust gas inflow side and the mixed catalyst obtained by mixing the second catalyst and the third catalyst faces the exhaust gas outflow side.
With this arrangement, nitrogen oxides can be effectively reduced and removed in a wide exhaust gas temperature range.
【0015】本発明の第二の排ガス浄化材では、多孔質
の無機酸化物に活性種として銀及び/又は銀化合物、又
はそれらの混合物0.2〜15重量%(銀元素換算値)
を担持してなる第一の触媒と、多孔質の無機酸化物に活
性種として銅の酸化物及び/又は硫酸塩0.2〜30重
量%(銅元素換算値)と、W、V、Moからなる群より
選ばれた少なくとも一種の元素の酸化物又は硫酸塩30
重量%以下(金属元素換算値)とを担持してなる第二の
触媒と、多孔質の無機酸化物に活性種としてPt、Pd、R
u、Rh、Ir及びAuからなる群より選ばれた少なくとも1
種の元素0.01〜5重量%(金属元素換算値)を担持
してなる第三の触媒とからなる排ガス浄化材を排ガス導
管中に設置し、浄化材の設置位置より上流側で炭化水素
と炭素数2以上の含酸素有機化合物のいずれか又はそれ
を含む燃料を添加した排ガスをこの浄化材に接触させ
て、排ガス中の窒素酸化物を還元除去する。第一の排ガ
ス浄化材同様、第二の排ガス浄化材は前記第一の触媒が
排ガス流入側に面し、前記第二の触媒と前記第三の触媒
とを混合してなる混合触媒が排ガス流出側に面するよう
に配置する。In the second exhaust gas purifying material of the present invention, 0.2 to 15% by weight of silver and / or a silver compound as an active species or a mixture thereof (in terms of silver element) is added to the porous inorganic oxide.
, A copper oxide and / or a sulfate as an active species in a porous inorganic oxide in an amount of 0.2 to 30% by weight (in terms of a copper element), W, V, and Mo. Oxide or sulfate of at least one element selected from the group consisting of
Weight% or less (in terms of a metal element) and a porous inorganic oxide containing Pt, Pd, and R as active species on a porous inorganic oxide.
at least one selected from the group consisting of u, Rh, Ir, and Au
An exhaust gas purifying material comprising a third catalyst carrying 0.01 to 5% by weight (converted to a metal element) of a seed element is installed in an exhaust gas conduit, and a hydrocarbon is provided upstream of the installation position of the purifying material. And an exhaust gas to which any one of oxygen-containing organic compounds having 2 or more carbon atoms or a fuel containing the same is added is brought into contact with the purification material to reduce and remove nitrogen oxides in the exhaust gas. Like the first exhaust gas purifying material, the second exhaust gas purifying material is such that the first catalyst faces the exhaust gas inflow side and the mixed catalyst obtained by mixing the second catalyst and the third catalyst flows out of the exhaust gas purifying material. Place it so that it faces the side.
【0016】本発明の排ガス浄化材の第一の好ましい形
態は、粉末状の多孔質無機酸化物に触媒活性種を担持し
てなる触媒を浄化材基体にコートしてなる浄化材であ
る。浄化材の基体を形成するセラミックス材料として
は、γ−アルミナ及びその酸化物(γ−アルミナ−チタ
ニア、γ−アルミナ−シリカ、γ−アルミナ−ジルコニ
ア等)、ジルコニア、チタニア−ジルコニアなどの多孔
質で表面積の大きい耐熱性のものが挙げられる。高耐熱
性が要求される場合、コージェライト、ムライト、アル
ミナ及びその複合物等を用いるのが好ましい。また、排
ガス浄化材の基体に公知の金属材料を用いることもでき
る。A first preferred embodiment of the exhaust gas purifying material of the present invention is a purifying material obtained by coating a purifying material base with a catalyst comprising a powdery porous inorganic oxide carrying catalytically active species. Examples of the ceramic material forming the substrate of the purifying material include porous materials such as γ-alumina and its oxides (γ-alumina-titania, γ-alumina-silica, γ-alumina-zirconia, etc.), zirconia, titania-zirconia, and the like. A heat-resistant material having a large surface area can be used. When high heat resistance is required, it is preferable to use cordierite, mullite, alumina and a composite thereof. In addition, a known metal material can be used for the base of the exhaust gas purifying material.
【0017】排ガス浄化材の基体の形状及び大きさは、
目的に応じて種々変更できる。実用的には、入口部分及
び出口部分等、二つの部分からなることが好ましい。ま
たその構造としては、ハニカム構造型、フォーム型、繊
維状耐火物からなる三次元網目構造型、あるいは顆粒
状、ペレット状等が挙げられる。The shape and size of the substrate of the exhaust gas purifying material are as follows:
Various changes can be made according to the purpose. Practically, it is preferable to have two parts such as an inlet part and an outlet part. Examples of the structure include a honeycomb structure type, a foam type, a three-dimensional network structure type formed of a fibrous refractory, a granular shape, a pellet shape, and the like.
【0018】本発明の排ガス浄化材の第二の好ましい形
態は、ペレット状又は顆粒状粉末状の多孔質無機酸化物
に触媒活性種を担持してなる触媒、又は触媒活性種をそ
れぞれ担持した粉末状多孔質無機酸化物をペレット状又
は顆粒状に成形したものを所望形状のケーシングに充填
してなる浄化材である。A second preferred embodiment of the exhaust gas purifying material of the present invention is a catalyst comprising a porous inorganic oxide in the form of a pellet or a granular powder carrying a catalytically active species, or a powder comprising a catalytically active species, respectively. It is a purifying material obtained by molding a porous inorganic oxide into pellets or granules into a casing having a desired shape.
【0019】本発明の浄化材には以下の触媒が形成され
ている。 (1)第一の触媒 第一の触媒は、多孔質無機酸化物に銀及び/又は銀化合
物、又はそれらの混合物を担持してなり、排ガスの流入
側に形成され、広い温度領域での窒素酸化物除去に作用
する。銀化合物は銀の酸化物、ハロゲン化銀、硫酸銀及
び燐酸銀などからなる群より選ばれた少なくとも一種で
あり、好ましくは銀の酸化物、塩化銀及び硫酸銀のいず
れか一種以上であり、更に好ましくは銀の酸化物及び/
又は塩化銀である。多孔質の無機酸化物としては、多孔
質のアルミナ、シリカ、チタニア、ジルコニア、ゼオラ
イト及びそれらの複合酸化物等を使用することができる
が、好ましくはγ−アルミナ、チタニアのいずれか又は
それらを含む複合酸化物を用いる。γ−アルミナ、チタ
ニア又はそれらの複合酸化物を用いることにより、添加
した炭化水素、含酸素有機化合物及び/又は排ガス中の
残留炭化水素と排ガス中の窒素酸化物との反応が効率良
く起こる。The following catalyst is formed on the purifying material of the present invention. (1) First catalyst The first catalyst is formed by supporting silver and / or a silver compound or a mixture thereof on a porous inorganic oxide, and is formed on the inflow side of exhaust gas. Acts on oxide removal. The silver compound is at least one selected from the group consisting of silver oxide, silver halide, silver sulfate, silver phosphate, and the like, and is preferably one or more of silver oxide, silver chloride, and silver sulfate, More preferably, a silver oxide and / or
Or silver chloride. As the porous inorganic oxide, porous alumina, silica, titania, zirconia, zeolite and composite oxides thereof and the like can be used, preferably γ-alumina, any of or including titania A composite oxide is used. By using γ-alumina, titania or a composite oxide thereof, the reaction between the added hydrocarbons, oxygen-containing organic compounds and / or residual hydrocarbons in the exhaust gas and nitrogen oxides in the exhaust gas occurs efficiently.
【0020】第一の触媒で用いるアルミナなどの多孔質
の無機酸化物の比表面積は10m2/g以上であるのが
好ましい。比表面積が10m2 /g未満であると、排ガ
スと無機酸化物(及びこれに担持した銀成分)との接触
面積が小さくなり、良好な窒素酸化物の除去が行えな
い。より好ましい多孔質無機酸化物の比表面積は30m
2 /g以上である。The specific surface area of the porous inorganic oxide such as alumina used for the first catalyst is preferably 10 m 2 / g or more. If the specific surface area is less than 10 m 2 / g, the contact area between the exhaust gas and the inorganic oxide (and the silver component carried thereon) becomes small, and good nitrogen oxides cannot be removed. More preferably, the specific surface area of the porous inorganic oxide is 30 m.
2 / g or more.
【0021】上記したγ−アルミナ等の無機酸化物に活
性種として担持する銀成分の担持量は、無機酸化物10
0重量%に対して0.2〜15重量%(銀元素換算値)
とする。0.2重量%未満では窒素酸化物の除去率が低
下する。また、15重量%を超す量の銀成分を担持する
と炭化水素及び/又は含酸素有機化合物自身の燃焼が起
きやすく、窒素酸化物の除去率はかえって低下する。好
ましい銀成分の担持量は0.5〜12重量%である。The amount of the silver component supported as an active species on the inorganic oxide such as γ-alumina is determined by the amount of the inorganic oxide 10
0.2 to 15% by weight with respect to 0% by weight (in terms of silver element)
And If the amount is less than 0.2% by weight, the removal rate of nitrogen oxides decreases. If the silver component is carried in an amount exceeding 15% by weight, the combustion of the hydrocarbon and / or the oxygen-containing organic compound itself tends to occur, and the nitrogen oxide removal rate is rather lowered. The preferred loading of the silver component is 0.5 to 12% by weight.
【0022】アルミナ等の無機酸化物に銀を担持する方
法としては、公知の含浸法、沈澱法等を用いることがで
きる。含浸法を用いる際、銀の硝酸塩、塩化物、硫酸
塩、炭酸塩等の水溶液又はアンモニア性水溶液に多孔質
無機酸化物を浸漬する。又は硝酸銀水溶液に多孔質無機
酸化物を浸漬し、乾燥後、塩化アンモニウム又は硫酸ア
ンモニウムの水溶液に再び浸漬する。沈澱法では硝酸銀
とハロゲン化アンモニウムとを反応させて、ハロゲン化
銀として多孔質無機酸化物上に沈澱させる。これを50
〜150℃、特に70℃程度で乾燥後、100〜600
℃で段階的に昇温して焼成するのが好ましい。焼成は、
空気中、酸素を含む窒素気流下や水素ガス気流下で行う
のが好ましい。水素ガス気流下で行う場合には、最後に
300〜650℃で酸化処理するのが好ましい。As a method for supporting silver on an inorganic oxide such as alumina, a known impregnation method, precipitation method, or the like can be used. When using the impregnation method, the porous inorganic oxide is immersed in an aqueous solution of silver nitrate, chloride, sulfate, carbonate, or the like, or an aqueous ammonia solution. Alternatively, the porous inorganic oxide is immersed in an aqueous solution of silver nitrate, dried, and then immersed again in an aqueous solution of ammonium chloride or ammonium sulfate. In the precipitation method, silver nitrate is reacted with ammonium halide to precipitate silver halide on the porous inorganic oxide. This is 50
After drying at about 150 ° C, especially about 70 ° C, 100 to 600
It is preferred to raise the temperature stepwise at a temperature of ° C. and to perform firing. Firing
It is preferable to carry out in air, under a flow of nitrogen containing oxygen or under a flow of hydrogen gas. When the treatment is performed under a hydrogen gas stream, it is preferable to perform the oxidation treatment at 300 to 650 ° C. at last.
【0023】硝酸銀等の水溶液を用いて多孔質無機酸化
物に担持された銀成分は酸化雰囲気下で焼成すると円状
集合体を形成することが観測されている。本発明の浄化
材では、銀成分集合体の平均直径を10〜10000n
mとするのが好ましい。一般的には、銀成分集合体の直
径が小さいほど、反応特性が高いが、平均直径が10n
m未満であると、還元剤である炭化水素及び/又は含酸
素有機化合物の酸化反応のみが進み、窒素酸化物の除去
率が低下する。一方、平均直径が10000nmを越え
ると、銀成分の反応特性が低減し、窒素酸化物の除去率
が下がる。好ましい銀成分集合体の平均直径は10〜5
000nm、更に好ましくは10〜2000nmとす
る。なお、ここで言う平均とは算術平均のことを意味す
る。It has been observed that a silver component supported on a porous inorganic oxide using an aqueous solution of silver nitrate or the like forms a circular aggregate when fired in an oxidizing atmosphere. In the purification material of the present invention, the average diameter of the silver component aggregate is 10 to 10,000 n
m is preferable. In general, the smaller the diameter of the silver component aggregate, the higher the reaction characteristics, but the average diameter is 10n.
If it is less than m, only the oxidation reaction of the hydrocarbon and / or the oxygen-containing organic compound as the reducing agent proceeds, and the nitrogen oxide removal rate decreases. On the other hand, when the average diameter exceeds 10,000 nm, the reaction characteristics of the silver component are reduced, and the nitrogen oxide removal rate is reduced. The average diameter of the preferred silver component aggregate is 10 to 5
000 nm, more preferably 10 to 2000 nm. Here, the average means an arithmetic average.
【0024】なお、浄化材の形態を上述した第一の好ま
しい形態とする場合、浄化材基体上に設ける第一の触媒
の厚さは、一般に、基体材と、この触媒との熱膨張特性
の違いから制限される場合が多い。浄化材基体上に設け
る触媒の厚さを300μm以下とするのがよい。このよ
うな厚さとすれば、使用中に熱衝撃等で浄化材が破損す
ることを防ぐことができる。浄化材基体の表面に触媒を
形成する方法は公知のウォシュコート法等によって行わ
れる。When the purifying material is in the above-described first preferred embodiment, the thickness of the first catalyst provided on the purifying material substrate generally depends on the thermal expansion characteristics of the substrate material and the catalyst. Often limited by differences. The thickness of the catalyst provided on the purifying material base is preferably 300 μm or less. With such a thickness, it is possible to prevent the purifying material from being damaged by thermal shock or the like during use. A method for forming a catalyst on the surface of the purifying material base is performed by a known washcoat method or the like.
【0025】また、浄化材基体の表面上に設ける第一触
媒の量は、浄化材基体の20〜300g/リットルとす
るのが好ましい。触媒の量が20g/リットル未満では
良好なNOx の除去が行えない。一方、触媒の量が300
g/リットルを超えると除去特性はそれほど上がらず、
圧力損失が大きくなる。より好ましくは、浄化材基体の
表面上に設ける第一の触媒を浄化材基体の50〜200
g/リットルとする。The amount of the first catalyst provided on the surface of the purifying material base is preferably 20 to 300 g / liter of the purifying material base. If the amount of the catalyst is less than 20 g / liter, good NOx removal cannot be performed. On the other hand, when the amount of the catalyst is 300
When the amount exceeds g / liter, the removal characteristics do not increase so much.
Pressure loss increases. More preferably, the first catalyst provided on the surface of the purifying material base is 50 to 200
g / liter.
【0026】(2)第二の触媒 第二の触媒は、多孔質無機酸化物に触媒活性種を担持し
てなる。多孔質無機酸化物としては、アルミナ、チタニ
ア及びゼオライトのいずれか又はそれらを含む複合酸化
物又はそれらの混合酸化物を用いるのが好ましい。第一
の触媒と同様に、多孔質の無機酸化物の比表面積は10
m2 /g以上であることが好ましい。(2) Second Catalyst The second catalyst comprises a porous inorganic oxide carrying catalytically active species. As the porous inorganic oxide, it is preferable to use any of alumina, titania and zeolite, a composite oxide containing them, or a mixed oxide thereof. As in the first catalyst, the specific surface area of the porous inorganic oxide is 10
It is preferably at least m 2 / g.
【0027】本発明の第一の排ガス浄化材では、上記の
第二の触媒の活性種としては銅の酸化物及び/又は硫酸
塩を用いる。第二の触媒を用いることにより、窒素酸化
物や第一触媒で生じる亜硝酸エステル、アンモニアなど
の含窒素化合物を窒素まで還元して、窒素酸化物の除去
が可能になる。多孔質無機酸化物を100重量%とし
て、銅成分の担持量は0.2〜30重量%(金属元素換
算値)であり、好ましい担持量が0.5〜25重量%
(金属元素換算値)である。In the first exhaust gas purifying material of the present invention, copper oxide and / or sulfate is used as the active species of the second catalyst. By using the second catalyst, nitrogen oxides can be reduced by reducing nitrogen oxides and nitrogen-containing compounds generated by the first catalyst, such as nitrite and ammonia, to nitrogen. Assuming that the porous inorganic oxide is 100% by weight, the supported amount of the copper component is 0.2 to 30% by weight (in terms of a metal element), and the preferable supported amount is 0.5 to 25% by weight.
(Metal element conversion value).
【0028】本発明の第二の排ガス浄化材では、上記の
第二の触媒の活性種としては銅の酸化物及び/又は硫酸
塩と、W、V、Moからなる群より選ばれた少なくとも
一種の元素の酸化物又は硫酸塩とを用いる。W、V、M
oのうち、W及び/又はVを用いるのが好ましい。第二
の触媒を用いることにより、窒素酸化物や第一触媒で生
じる亜硝酸エステル、アンモニアなどの含窒素化合物を
窒素まで還元して、窒素酸化物の除去が可能になる。多
孔質無機酸化物を100重量%として、銅の酸化物又は
硫酸銅の担持量は0.2〜30重量%(金属元素換算
値)であり、W系成分の担持量は30重量%以下(金属
元素換算値)である。また銅成分とW系成分との合計担
持量は0.2〜60重量%(金属元素換算値)(金属元
素換算値)である。銅成分の好ましい担持量が0.5〜
25重量%(金属元素換算値)であり、W系成分の好ま
しい担持量は25重量%以下(金属元素換算値)であ
り、銅成分とW系成分との好ましい合計担持量は0.5
〜50重量%(金属元素換算値)とする。In the second exhaust gas purifying material of the present invention, the active species of the second catalyst is at least one selected from the group consisting of oxides and / or sulfates of copper and W, V and Mo. And an oxide or a sulfate of the element (a). W, V, M
Of o, it is preferable to use W and / or V. By using the second catalyst, nitrogen oxides can be reduced by reducing nitrogen oxides and nitrogen-containing compounds generated by the first catalyst, such as nitrite and ammonia, to nitrogen. Assuming that the porous inorganic oxide is 100% by weight, the supported amount of the copper oxide or copper sulfate is 0.2 to 30% by weight (in terms of a metal element), and the supported amount of the W-based component is 30% by weight or less ( Metal element). The total amount of the copper component and the W-based component is 0.2 to 60% by weight (converted to metal element) (converted to metal element). The preferred loading of the copper component is 0.5 to
It is 25% by weight (in terms of metal element), the preferred amount of the W-based component is 25% by weight or less (in terms of metal element), and the preferred total amount of the copper component and the W-based component is 0.5.
To 50% by weight (in terms of metal element).
【0029】第二の触媒における活性種の担持は、公知
の含浸法、沈殿法等を用いることができる。含浸法を用
いる際、触媒活性種元素の炭酸塩、硝酸塩、酢酸塩、硫
酸塩等の水溶液に多孔質無機酸化物を浸漬する。銅成分
の場合、硫酸銅、硝酸銅などの水溶液を用いる。W、
V、Moの場合、各元素のアンモニウム塩、しゅう酸塩
等の水溶液に多孔質無機酸化物を浸漬して用いる。50
〜150℃、特に70℃で乾燥後、100〜600℃で
段階的に昇温して焼成することによって行われる。この
焼成は空気中、酸素を含む窒素気流下で行う。また、チ
タニアの代わりにメタチタン酸(含水酸化チタン)を出
発物質として用い、V、W、Moを担持することも有効
な方法である。For loading the active species on the second catalyst, a known impregnation method, precipitation method or the like can be used. When using the impregnation method, the porous inorganic oxide is immersed in an aqueous solution of a carbonate, nitrate, acetate, sulfate or the like of the catalytically active species element. In the case of a copper component, an aqueous solution such as copper sulfate or copper nitrate is used. W,
In the case of V or Mo, a porous inorganic oxide is immersed in an aqueous solution of an ammonium salt, oxalate or the like of each element for use. 50
After drying at ~ 150 ° C, especially at 70 ° C, the temperature is raised stepwise at 100-600 ° C and firing is performed. This calcination is performed in air under a nitrogen stream containing oxygen. It is also an effective method to use metatitanic acid (hydrous titanium oxide) as a starting material instead of titania and to carry V, W, and Mo.
【0030】なお、浄化材の形態を上述した第一の好ま
しい形態とする場合、浄化材基体上に設ける第二の触媒
の厚さを300μm以下とするのがよい。また、浄化材
基体の表面上に設ける第二の触媒の量は、浄化材基体の
20〜300g/リットルとするのが好ましい。When the form of the purifying material is the first preferred embodiment described above, the thickness of the second catalyst provided on the purifying material base is preferably 300 μm or less. The amount of the second catalyst provided on the surface of the purifying material base is preferably 20 to 300 g / liter of the purifying material base.
【0031】(3)第三の触媒 第三の触媒は、多孔質無機酸化物に触媒活性種を担持し
てなり、排ガスの流出側に形成され、低い温度領域にお
ける窒素酸化物の除去に作用するとともに、一酸化炭素
や炭化水素の酸化除去を行う。多孔質無機酸化物として
は、アルミナ、チタニア、ジルコニア、シリカ、ゼオラ
イトからなる群より選ばれた一種以上の酸化物又は複合
酸化物を用いるのが好ましい。第一の触媒と同様に、多
孔質の無機酸化物の比表面積は10m2 /g以上である
ことが好ましい。(3) Third Catalyst The third catalyst comprises a porous inorganic oxide carrying catalytically active species and is formed on the exhaust gas outflow side, and acts to remove nitrogen oxides in a low temperature region. And at the same time, oxidize and remove carbon monoxide and hydrocarbons. As the porous inorganic oxide, it is preferable to use one or more oxides or composite oxides selected from the group consisting of alumina, titania, zirconia, silica, and zeolite. Similar to the first catalyst, the specific surface area of the porous inorganic oxide is preferably 10 m 2 / g or more.
【0032】上記の第三触媒の活性種としては、Pt、P
d、Ru、Rh、Ir及びAuからなる群より選ばれた少なくと
も1種の元素を用い、Pt、Pd、Ru、Rh及びAuの少なくと
も一種を用いるのが好ましく、特にPt、Pd及びAuの少な
くとも一種が好ましい。第三の触媒で無機酸化物に担持
する活性種の合計は、上述の多孔質の無機酸化物を基準
(100重量%) として0.01〜5重量%とし、好ましく
は0.01〜4重量%とする。触媒活性種の量が前記多
孔質無機酸化物に対して、5重量%を超す触媒担持量と
しても窒素酸化物の除去性能が向上しない。The active species of the above third catalyst include Pt, P
d, Ru, Rh, using at least one element selected from the group consisting of Ir and Au, it is preferable to use at least one of Pt, Pd, Ru, Rh and Au, particularly at least Pt, Pd and Au One is preferred. The total of the active species supported on the inorganic oxide by the third catalyst is based on the above-mentioned porous inorganic oxide.
(100% by weight) is 0.01 to 5% by weight, preferably 0.01 to 4% by weight. Even when the amount of the catalytically active species exceeds 5% by weight of the porous inorganic oxide, the performance of removing nitrogen oxides is not improved.
【0033】また、第三の触媒の活性種として、さら
に、La、Ce等の希土類元素、Ca、Mgなどのアルカリ土類
元素、Na、Kなどのアルカリ金属元素からなる群より選
ばれた少なくとも一つ以上の元素を10重量%以下担持
することが好ましい。希土類、アルカリ土類、アルカリ
金属元素を担持することにより、白金系の触媒の耐熱性
を向上させることができる。The active species of the third catalyst may further include at least one selected from the group consisting of rare earth elements such as La and Ce, alkaline earth elements such as Ca and Mg, and alkali metal elements such as Na and K. It is preferable to carry one or more elements in an amount of 10% by weight or less. By supporting a rare earth, alkaline earth, or alkali metal element, the heat resistance of a platinum-based catalyst can be improved.
【0034】第三の触媒における活性種の担持は、公知
の含浸法、沈澱法等を用いることができる。含浸法を用
いる際、触媒活性種元素の塩化物又はヘキサクロロ金属
酸等の水溶液に多孔質無機酸化物を浸漬し、70℃で乾
燥後、100〜700℃で段階的に昇温して焼成するこ
とによって行われる。焼成は窒素気流下、水素含有又は
酸素含有窒素気流下で行い、好ましくは窒素気流下で焼
成した後、水素含有窒素気流下、酸素含有窒素気流下で
それぞれ焼成を行う。なお、Pt系担持成分は金属元素と
して表示しているが、通常の浄化材の使用温度条件では
担持成分は金属と酸化物の状態で存在する。For loading the active species on the third catalyst, a known impregnation method, precipitation method or the like can be used. When using the impregnation method, the porous inorganic oxide is immersed in an aqueous solution such as a chloride or hexachlorometallic acid of a catalytically active species element, dried at 70 ° C., and then gradually heated at 100 to 700 ° C. and fired. This is done by: The calcination is performed under a nitrogen stream or a hydrogen-containing or oxygen-containing nitrogen stream. Preferably, the calcination is performed under a nitrogen stream, and then the calcination is performed under a hydrogen-containing nitrogen stream or an oxygen-containing nitrogen stream. Although the Pt-based loading component is shown as a metal element, the loading component exists in a state of a metal and an oxide under a normal use temperature condition of the purification material.
【0035】なお、浄化材の形態を上述した第一の好ま
しい形態とする場合、浄化材基体上に設ける第三の触媒
の厚さを300μm以下とするのがよい。また、浄化材
基体の表面上に設ける第三の触媒の量は、浄化材基体に
対して20〜300g/リットルとするのが好ましい。When the form of the purifying material is the first preferred embodiment described above, the thickness of the third catalyst provided on the purifying material base is preferably 300 μm or less. The amount of the third catalyst provided on the surface of the purifying material base is preferably 20 to 300 g / liter based on the purifying material base.
【0036】本発明では、第二の触媒と第三の触媒を混
合して用いる。この混合によって、第二の触媒の還元作
用と第三の触媒の酸化作用が互いに影響することなく同
時に進行することができる。浄化材が上記第一の好まし
い形態である場合、浄化材基体上に設ける第二の触媒と
第三の触媒との混合触媒の厚さを300μm以下とする
のがよい。また、浄化材基体の表面上に設ける第二の触
媒と第三の触媒との混合触媒の量は、浄化材基体に対し
て20〜300g/リットルとするのが好ましい。In the present invention, the second catalyst and the third catalyst are mixed and used. By this mixing, the reducing action of the second catalyst and the oxidizing action of the third catalyst can proceed simultaneously without affecting each other. In the case where the purifying material is the first preferred embodiment, the thickness of the mixed catalyst of the second catalyst and the third catalyst provided on the purifying material base is preferably 300 μm or less. Further, the amount of the mixed catalyst of the second catalyst and the third catalyst provided on the surface of the purifying material base is preferably 20 to 300 g / liter with respect to the purifying material base.
【0037】第二の触媒と第三の触媒との重量比(多孔
質無機酸化物と触媒活性種との合計重量の比)は、10
0:1〜100:50とするのが好ましい。第二の触媒
100重量部に対して第三の触媒が1重量部未満の場合
では、炭化水素、一酸化炭素の除去率が低下する。一
方、第二の触媒100重量部に対して第三の触媒が50
重量部を越えると、150〜600℃の広い温度範囲で
全体的に窒素酸化物の浄化率が低下する。より好ましい
第二の触媒と第三の触媒の重量比は100:1〜10
0:30である。The weight ratio of the second catalyst to the third catalyst (the ratio of the total weight of the porous inorganic oxide to the catalytically active species) is 10
The ratio is preferably set to 0: 1 to 100: 50. If the amount of the third catalyst is less than 1 part by weight based on 100 parts by weight of the second catalyst, the removal rate of hydrocarbons and carbon monoxide decreases. On the other hand, 50 parts by weight of the third catalyst were added to 100 parts by weight of the second catalyst.
If the amount is more than 100 parts by weight, the purification rate of nitrogen oxides is lowered as a whole in a wide temperature range of 150 to 600 ° C. More preferably, the weight ratio of the second catalyst to the third catalyst is 100: 1 to 10
0:30.
【0038】本発明においては、第一の触媒と、第二の
触媒と第三の触媒との混合触媒との重量比(多孔質無機
酸化物と触媒活性種との合計重量の比)は、10:1〜
1:5とするのが好ましい。比率が1:5未満である
(第一の触媒が少ない)と、150〜600℃の広い温
度範囲で全体的に窒素酸化物の浄化率が低下する。一
方、比率が10:1を超え、混合触媒が少ないと、第一
の触媒上でできた亜硝酸エステル、アンモニア等の含窒
素化合物が反応せず、そのまま排出されたり、一酸化炭
素、炭化水素の除去率が低下する。より好ましい第一触
媒と混合触媒の重量比は5:1〜1:4である。In the present invention, the weight ratio of the first catalyst to the mixed catalyst of the second catalyst and the third catalyst (the ratio of the total weight of the porous inorganic oxide to the catalytically active species) is: 10: 1 to 1
The ratio is preferably set to 1: 5. When the ratio is less than 1: 5 (the amount of the first catalyst is small), the purification rate of nitrogen oxides is reduced overall in a wide temperature range of 150 to 600 ° C. On the other hand, when the ratio exceeds 10: 1 and the amount of the mixed catalyst is small, the nitrogen-containing compounds such as nitrites and ammonia formed on the first catalyst do not react and are discharged as they are, or they are discharged as they are, carbon monoxide, hydrocarbons or the like. Removal rate decreases. More preferably, the weight ratio of the first catalyst to the mixed catalyst is 5: 1 to 1: 4.
【0039】上述した構成の浄化材を用いれば、150
〜600℃の広い温度領域において、水分10%程度及
び硫黄酸化物を含む排ガスでも、良好な窒素酸化物の除
去を行うことができる。If the purifying material having the above configuration is used, 150
In a wide temperature range of up to 600 ° C., good removal of nitrogen oxides can be performed even with an exhaust gas containing about 10% of moisture and sulfur oxides.
【0040】次に、本発明の方法について説明する。ま
ず、第一の触媒が排ガスの入口に面し、第二の触媒と第
三の触媒とを混合してなる混合触媒が排ガスの出口に面
あるように排ガス浄化材を排ガス導管の途中に設置す
る。Next, the method of the present invention will be described. First, an exhaust gas purifying material is installed in the exhaust gas conduit so that the first catalyst faces the exhaust gas inlet and the mixed catalyst obtained by mixing the second catalyst and the third catalyst is at the exhaust gas outlet. I do.
【0041】排ガス中には、残留炭化水素としてエチレ
ン、プロピレン等がある程度は含まれるが、一般に排ガ
ス中のNOx を還元するのに十分な量ではないので、外部
から炭化水素及び/又は含酸素有機化合物、好ましくは
含酸素有機化合物又はそれと炭化水素燃料と混合してな
る還元剤を排ガス中に導入する。還元剤の導入位置は、
浄化材を設置した位置より上流側である。The exhaust gas contains ethylene, propylene and the like to some extent as residual hydrocarbons. However, the amount is generally not sufficient to reduce NOx in the exhaust gas. A compound, preferably an oxygen-containing organic compound or a reducing agent obtained by mixing the compound with a hydrocarbon fuel is introduced into the exhaust gas. The introduction position of the reducing agent
It is upstream from the position where the purifying material is installed.
【0042】外部から導入する炭化水素としては、標準
状態でガス状又は液体状のアルカン、アルケン及び/又
はアルキンを用いることができる。特にアルカン又はア
ルケンの場合では炭素数2以上が好ましい。標準状態で
液体状の炭化水素としては、具体的に、軽油、セタン、
ヘプタン、灯油、ガソリン等の炭化水素が挙げられる。
その中でも、沸点50〜350℃の炭化水素が特に好ま
しい。外部から導入する含酸素有機化合物として、炭素
数2以上のエタノール、イソプロピルアルコール等のア
ルコール類、又はそれらを含む燃料を用いることができ
る。As the hydrocarbon introduced from the outside, gaseous or liquid alkanes, alkenes and / or alkynes can be used under standard conditions. In particular, in the case of an alkane or alkene, it preferably has 2 or more carbon atoms. Specific examples of hydrocarbons that are liquid in the standard state include gas oil, cetane,
Examples include hydrocarbons such as heptane, kerosene, gasoline and the like.
Among them, hydrocarbons having a boiling point of 50 to 350 ° C are particularly preferable. As the oxygen-containing organic compound introduced from the outside, alcohols such as ethanol and isopropyl alcohol having 2 or more carbon atoms, or a fuel containing them can be used.
【0043】外部から導入する炭化水素及び/又は含酸
素有機化合物の量は、重量比(添加する還元剤の重量/
排ガス中の窒素酸化物の重量)が0.1〜5となるよう
にするのが好ましい。この重量比が0.1未満である
と、窒素酸化物の除去率が大きくならない。一方、5を
超えると、燃費悪化につながる。The amount of the hydrocarbon and / or oxygen-containing organic compound introduced from the outside is determined by the weight ratio (weight of the reducing agent to be added / weight).
(Weight of nitrogen oxides in the exhaust gas) is preferably 0.1 to 5. If the weight ratio is less than 0.1, the removal rate of nitrogen oxides does not increase. On the other hand, if it exceeds 5, fuel efficiency will be degraded.
【0044】また、炭化水素又は含酸素有機化合物を含
有する燃料を添加する場合、燃料としてガソリン、軽
油、灯油などを用いるのが好ましい。この場合、還元剤
の量は上記と同様に重量比(添加する還元剤の重量/排
ガス中の窒素酸化物の重量)が0.1〜5となるように
設定する。When a fuel containing a hydrocarbon or an oxygen-containing organic compound is added, it is preferable to use gasoline, light oil, kerosene or the like as the fuel. In this case, the amount of the reducing agent is set such that the weight ratio (the weight of the reducing agent to be added / the weight of the nitrogen oxide in the exhaust gas) is 0.1 to 5 in the same manner as described above.
【0045】本発明では、含酸素有機化合物、炭化水素
又はアンモニア等による窒素酸化物の還元除去を効率的
に進行させるために、第一の触媒(銀系触媒)における
空間速度は 150,000h-1以下、好ましくは 100,000h-1
以下とする。第一の触媒の空間速度が 150,000h-1を越
えると、窒素酸化物の還元反応が十分に起こらず、窒素
酸化物の除去率が低下する。第二の触媒と第三の触媒を
混合してなる触媒における空間速度は 200,000h-1以
下、好ましくは 150,000h-1以下とする。In the present invention, the space velocity of the first catalyst (silver-based catalyst) is 150,000 h -1 in order to efficiently promote the reduction and removal of nitrogen oxides by an oxygen-containing organic compound, hydrocarbon or ammonia. Or less, preferably 100,000h -1
The following is assumed. When the space velocity of the first catalyst exceeds 150,000 h -1 , the reduction reaction of nitrogen oxides does not sufficiently occur, and the nitrogen oxide removal rate decreases. The space velocity in the catalyst obtained by mixing a second catalyst and the third catalyst 200,000 -1 or less, preferably 150,000H -1 or less.
【0046】また、本発明では、炭化水素及び/又は含
酸素有機化合物と窒素酸化物とが反応する部位である浄
化材設置部位における排ガスの温度を150〜600℃
に保つ。排ガスの温度が150℃未満であると還元剤と
窒素酸化物との反応が進行せず、良好な窒素酸化物の除
去を行うことができない。一方、600℃を超す温度と
すると炭化水素及び/又は含酸素有機化合物自身の燃焼
が始まり、窒素酸化物の還元除去が行えない。好ましい
排ガス温度は200〜550℃であり、より好ましくは
300〜500℃である。In the present invention, the temperature of the exhaust gas at the purification material installation site, which is the site where the hydrocarbon and / or the oxygen-containing organic compound reacts with the nitrogen oxide, is set to 150 to 600 ° C.
To keep. If the temperature of the exhaust gas is lower than 150 ° C., the reaction between the reducing agent and the nitrogen oxide does not proceed, and it is not possible to remove the nitrogen oxide satisfactorily. On the other hand, if the temperature exceeds 600 ° C., the combustion of the hydrocarbon and / or the oxygen-containing organic compound itself starts, and the reduction and removal of nitrogen oxides cannot be performed. The preferred exhaust gas temperature is from 200 to 550C, more preferably from 300 to 500C.
【0047】[0047]
【実施例】本発明を以下の具体的実施例によりさらに詳
細に説明する。実施例1 市販のγ−アルミナ粉末(比表面積200m2 /g)を
硝酸銀水溶液に浸漬したあと取り出して、70℃で2時
間乾燥した。そして、空気中で、段階的に600℃まで
昇温したあと、5時間焼成し、アルミナに対して3.1
重量%(金属元素換算値)の銀を担持した第一の触媒を
調製した。第一の触媒0.26gを、市販のコージェラ
イト製ハニカム状成形体(直径20mm、長さ8.3m
m、400セル/インチ2 )にコートし、乾燥後600
℃まで段階的に焼成し、銀系浄化材(第一の触媒をコー
トした浄化材)を調製した。The present invention will be described in more detail with reference to the following specific examples. Example 1 A commercially available γ-alumina powder (specific surface area: 200 m 2 / g) was immersed in an aqueous silver nitrate solution, taken out, and dried at 70 ° C. for 2 hours. Then, the temperature is raised stepwise to 600 ° C. in the air, and calcined for 5 hours.
A first catalyst supporting silver by weight (in terms of a metal element) was prepared. 0.26 g of the first catalyst was charged with a commercially available cordierite honeycomb formed body (diameter 20 mm, length 8.3 m).
m, 400 cells / inch 2 ) and after drying 600
The mixture was baked stepwise to ℃ to prepare a silver-based purifying material (a purifying material coated with a first catalyst).
【0048】次に、硫酸銅水溶液(銅濃度7.7重量
%)に粉末状チタニア(比表面積50m2 /g)を浸漬
し、空気中で、80℃、100℃、120℃で各2時間
乾燥した。続いて、酸素を20%含む窒素気流下で12
0℃〜500℃まで段階的に昇温し500℃で5時間焼
成し、チタニアに対して硫酸銅4.4重量%(銅元素換
算値)を担持した第二の触媒を調製した。Next, powdery titania (specific surface area: 50 m 2 / g) is immersed in an aqueous solution of copper sulfate (copper concentration: 7.7% by weight), and in air at 80 ° C., 100 ° C. and 120 ° C. for 2 hours each. Dried. Subsequently, under a nitrogen stream containing 20% of oxygen, 12
The temperature was increased stepwise from 0 ° C. to 500 ° C. and calcined at 500 ° C. for 5 hours to prepare a second catalyst supporting 4.4% by weight of copper sulfate (converted to copper element) with respect to titania.
【0049】さらに、同様のチタニアを塩化白金酸水溶
液に20分間浸漬した後、空気中、80℃で2時間乾燥
し、窒素気流下で120℃で2時間、200〜400℃
まで段階的に各1時間焼成した。そして、水素ガス4%
を含む窒素気流下で50℃〜400℃まで5時間かけて
昇温し、400℃で4時間焼成し、さらに、酸素を10
%含む窒素気流下で50℃〜500℃まで5時間かけて
昇温し、500℃で5時間焼成し、チタニアに対してPt
を0.21重量%(金属元素換算値)担持した第三の触
媒を調製した。Further, the same titania was immersed in an aqueous solution of chloroplatinic acid for 20 minutes, dried in air at 80 ° C. for 2 hours, and dried at 120 ° C. for 2 hours in a nitrogen stream at 200 to 400 ° C.
Each step was baked for 1 hour. And 4% hydrogen gas
The temperature was raised from 50 ° C. to 400 ° C. over 5 hours under a nitrogen stream containing, and calcined at 400 ° C. for 4 hours.
% In a nitrogen stream containing 5% over a period of 5 hours from 50 ° C. to 500 ° C., and calcined at 500 ° C. for 5 hours.
Was prepared at a concentration of 0.21% by weight (in terms of a metal element).
【0050】第二の触媒と第三の触媒の重量比が40:
1になるように第二の触媒と第三の触媒を混合してスラ
リー化した後、上記銀系浄化材と同様なハニカム成形体
に0.26gの混合触媒をコートし。銀系浄化材と同じ
条件で乾燥、焼成を行い、銅、白金系浄化材(第二、第
三の触媒をコートした浄化材)を調製した。The weight ratio of the second catalyst to the third catalyst is 40:
After mixing the second catalyst and the third catalyst so as to obtain a slurry and forming a slurry, 0.26 g of the mixed catalyst was coated on a honeycomb formed body similar to the silver-based purifying material. Drying and baking were performed under the same conditions as those for the silver-based purifying material to prepare copper and platinum-based purifying materials (purifying materials coated with the second and third catalysts).
【0051】反応管内の排ガスの流入側に銀系浄化材、
流出側に銅、白金系浄化材をそれぞれセットした。次
に、表1に示す組成のガス(一酸化窒素、酸素、エタノ
ール、二酸化硫黄、窒素及び水分)を毎分3.48リッ
トル(標準状態)の流量で流して(銀系浄化材と銅、白
金系浄化材の見かけ空間速度はそれぞれ約80,000
h-1である)、反応管内の排ガス温度を350〜550
℃の範囲に保ち、エタノールと窒素酸化物とを反応させ
た。A silver-based purifying material is provided on the exhaust gas inflow side in the reaction tube,
Copper and platinum-based purifying materials were set on the outflow side. Next, a gas having the composition shown in Table 1 (nitrogen monoxide, oxygen, ethanol, sulfur dioxide, nitrogen and moisture) was flowed at a flow rate of 3.48 liters per minute (standard state) (silver-based purifying material and copper, The apparent space velocity of platinum-based purification material is about 80,000 each
h -1 ), and the temperature of the exhaust gas in the reaction tube is set to 350 to 550.
While maintaining the temperature in the range of ° C., ethanol and nitrogen oxide were reacted.
【0052】反応管通過後のガスの窒素酸化物の濃度を
化学発光式窒素酸化物分析計により測定し、窒素酸化物
除去率を求めた。結果を表2に示す。The concentration of nitrogen oxides in the gas after passing through the reaction tube was measured with a chemiluminescent nitrogen oxide analyzer to determine the nitrogen oxide removal rate. Table 2 shows the results.
【0053】表1成分 濃度 一酸化窒素 800 ppm 酸素 10 容量% エタノール 1560 ppm 二酸化硫黄 30 ppm窒素 残部 水分 10 容量%(上記成分の総体積に対し
て)Table 1 Component concentration Nitric oxide 800 ppm Oxygen 10% by volume Ethanol 1560 ppm Sulfur dioxide 30 ppm Nitrogen Residual water 10% by volume (based on the total volume of the above components)
【0054】実施例2 タングステン酸アンモニウムパラ五水和物、しゅう酸に
水を加え、水浴上で加熱して溶解させた後、冷却した水
溶液(タングステン濃度15.5重量%)に、粉末状チ
タニア(比表面積50m2 /g)を投入し、20分間浸
漬した。その後、溶液からチタニアを分離し、空気中
で、80℃、100℃、120℃で各2時間乾燥した。
続いて、酸素20%を含む窒素気流下で120℃から5
00℃まで5時間かけで昇温し、500℃で4時間焼成
して、チタニアに対してWの酸化物を7.4重量%(金
属元素換算値)担持したW系触媒を調製した。この触媒
を硫酸銅水溶液(銅濃度9.0重量%)に20分間浸漬
し、そして実施例1の第二の触媒と同じ方法で乾燥、焼
成し、チタニアに対してWの酸化物7.4重量%、硫酸
銅3.7重量%(金属元素換算値)を担持した第二の触
媒を調製した。 Example 2 Water was added to ammonium paratungstate parapentahydrate and oxalic acid, dissolved by heating on a water bath, and then added to a cooled aqueous solution (tungsten concentration: 15.5% by weight) to obtain a powdery titania. (Specific surface area: 50 m 2 / g) and immersed for 20 minutes. Thereafter, the titania was separated from the solution, and dried in air at 80 ° C, 100 ° C, and 120 ° C for 2 hours each.
Subsequently, the temperature is changed from 120 ° C. to 5 ° C under a nitrogen stream containing 20% of oxygen.
The temperature was raised to 00 ° C. in 5 hours and calcined at 500 ° C. for 4 hours to prepare a W-based catalyst supporting 7.4% by weight (in terms of metal element) of an oxide of W with respect to titania. This catalyst was immersed in an aqueous solution of copper sulfate (copper concentration: 9.0% by weight) for 20 minutes, and dried and calcined in the same manner as the second catalyst of Example 1 to obtain an oxide of W with respect to titania of 7.4. A second catalyst was prepared, which supported 3.7% by weight of copper sulfate and 3.7% by weight (in terms of metal element).
【0055】上記第二の触媒と実施例1で調製した第三
の触媒を重量比が40:1になるように混合してスラリ
ー化した後、実施例1と同じ方法でハニカム成形体に
0.26gの混合触媒をコートし、乾燥、焼成を行い、
銅、W、白金系浄化材(第二、第三の触媒をコートした
浄化材)を調製した。The above-mentioned second catalyst and the third catalyst prepared in Example 1 were mixed at a weight ratio of 40: 1 to form a slurry. .26 g of the mixed catalyst was coated, dried and calcined,
Copper, W, and platinum-based purifying materials (purifying materials coated with second and third catalysts) were prepared.
【0056】反応管内の排ガスの流入側に実施例1の銀
系浄化材、流出側に銅、W、白金系浄化材をそれぞれセ
ットした。実施例1と同様の反応条件(銀系浄化材と
銅、W、白金系浄化材の見かけ空間速度はそれぞれ約8
0,000h-1である)で、表1に示す組成のガスを用
いて評価を行った。結果を表2に示す。The silver-based purifying material of Example 1 was set on the inflow side of the exhaust gas in the reaction tube, and the copper, W, and platinum-based purifying materials were set on the outflow side. The same reaction conditions as in Example 1 (the apparent space velocities of the silver-based purifying material and the copper, W, and platinum-based purifying materials were about 8
(At 0000 h −1 )), and the evaluation was performed using a gas having a composition shown in Table 1. Table 2 shows the results.
【0057】実施例3 五酸化バナジウムにしゅう酸を加え、水浴上で加熱して
溶解させた後、冷却した水溶液(バナジウム濃度7.8
重量%)に、粉末状チタニア(比表面積50m2 /g)
を投入し、20分間浸漬した。その後、溶液からチタニ
アを分離し、空気中で、80℃、100℃、120℃で
各2時間乾燥した。続いて、酸素20%を含む窒素気流
下で120℃〜500℃まで5時間かけで昇温し、50
0℃で4時間焼成して、チタニアに対してV酸化物を
3.8重量%(金属元素換算値)担持したV系触媒を調
製した。このV系触媒3.3g(見掛け体積3.1m
l)を硫酸銅水溶液(銅濃度9.0重量%)に20分間
浸漬し、そして実施例1の第二の触媒と同じ方法で乾
燥、焼成し、チタニアに対してVの酸化物3.8重量
%、硫酸銅4.0重量%(金属元素換算値)を担持した
第二の触媒を調製した。 Example 3 Oxalic acid was added to vanadium pentoxide, and dissolved by heating on a water bath, and then cooled and cooled (a vanadium concentration of 7.8).
% By weight), powdered titania (specific surface area: 50 m 2 / g)
, And immersed for 20 minutes. Thereafter, the titania was separated from the solution, and dried in air at 80 ° C, 100 ° C, and 120 ° C for 2 hours each. Subsequently, the temperature was increased from 120 ° C. to 500 ° C. in 5 hours under a nitrogen stream containing 20% of oxygen, and 50 ° C.
By calcining at 0 ° C. for 4 hours, a V-based catalyst carrying 3.8% by weight (converted to metal element) of V oxide with respect to titania was prepared. 3.3 g of this V-based catalyst (3.1 m in apparent volume)
l) was immersed in an aqueous solution of copper sulfate (copper concentration: 9.0% by weight) for 20 minutes and dried and calcined in the same manner as the second catalyst of Example 1 to obtain an oxide of V against titania of 3.8. A second catalyst was prepared, which supported 4.0% by weight of copper sulfate and 4.0% by weight of copper sulfate (in terms of metal element).
【0058】上記第二の触媒と実施例1で調製した第三
の触媒を重量比が20:1になるように混合してスラリ
ー化した後、実施例1と同じ方法でハニカム成形体に
0.26gの混合触媒をコートし、乾燥、焼成を行い、
銅、V、白金系浄化材(第二、第三の触媒をコートした
浄化材)を調製した。The second catalyst and the third catalyst prepared in Example 1 were mixed at a weight ratio of 20: 1 to form a slurry. .26 g of the mixed catalyst was coated, dried and calcined,
Copper, V, and platinum-based purifying materials (purifying materials coated with second and third catalysts) were prepared.
【0059】反応管内の排ガスの流入側に実施例1の銀
系浄化材、流出側に銅、V、白金系浄化材をそれぞれセ
ットした。実施例1と同様の反応条件(銀系浄化材と
銅、V、白金系浄化材の見かけ空間速度はそれぞれ約8
0,000h-1である)で、表1に示す組成のガスを用
いて評価を行った。結果を表2に示す。The silver-based purifying material of Example 1 was set on the inflow side of the exhaust gas in the reaction tube, and the copper, V, and platinum-based purifying materials were set on the outflow side. The same reaction conditions as in Example 1 (the apparent space velocities of the silver-based purifying material and the copper, V, and platinum-based purifying materials were about 8
(At 0000 h −1 )), and the evaluation was performed using a gas having a composition shown in Table 1. Table 2 shows the results.
【0060】実施例4 実施例3で調製したV系触媒3.3g(見掛け体積3.
1ml)を硝酸銅水溶液(銅濃度9.5重量%)に20
分間浸漬し、そして実施例1の第二の触媒と同じ方法で
乾燥、焼成し、チタニアに対してVの酸化物3.8重量
%、銅の酸化物4.5重量%(金属元素換算値)を担持
した第二の触媒を調製した。 Example 4 3.3 g of V-based catalyst prepared in Example 3 (apparent volume: 3.
1 ml) in an aqueous solution of copper nitrate (copper concentration 9.5% by weight).
For 2 minutes, and dried and calcined in the same manner as in the second catalyst of Example 1 to obtain 3.8% by weight of an oxide of V and 4.5% by weight of an oxide of copper with respect to titania (in terms of a metal element). ) Was prepared.
【0061】上記第二の触媒と実施例1で調製した第三
の触媒を重量比が20:1になるように混合してスラリ
ー化した後、実施例1と同じ方法でハニカム成形体に
0.26gの混合触媒をコートし、乾燥、焼成を行い、
銅、V、白金系浄化材(第二、第三の触媒をコートした
浄化材)を調製した。The second catalyst and the third catalyst prepared in Example 1 were mixed at a weight ratio of 20: 1 to form a slurry. .26 g of the mixed catalyst was coated, dried and calcined,
Copper, V, and platinum-based purifying materials (purifying materials coated with second and third catalysts) were prepared.
【0062】反応管内の排ガスの流入側に実施例1の銀
系浄化材、流出側に銅、V、白金系浄化材をそれぞれセ
ットした。実施例1と同様の反応条件(銀系浄化材と
銅、V、白金系浄化材の見かけ空間速度はそれぞれ約8
0,000h-1である)で、表1に示す組成のガスを用
いて評価を行った。結果を表2に示す。The silver-based purifying material of Example 1 was set on the inflow side of the exhaust gas in the reaction tube, and the copper, V, and platinum-based purifying materials were set on the outflow side. The same reaction conditions as in Example 1 (the apparent space velocities of the silver-based purifying material and the copper, V, and platinum-based purifying materials were about 8
(At 0000 h −1 )), and the evaluation was performed using a gas having a composition shown in Table 1. Table 2 shows the results.
【0063】実施例5 実施例1と同じ方法で粉末状チタニアを硝酸銅水溶液
(銅濃度9.5重量%)に20分間浸漬し、そして実施
例1の第二の触媒と同じ方法で乾燥、焼成し、チタニア
に対して銅の酸化物4.5重量%(金属元素換算値)を
担持した第二の触媒を調製した。 Example 5 Powdered titania was immersed in an aqueous solution of copper nitrate (copper concentration: 9.5% by weight) for 20 minutes in the same manner as in Example 1, and dried in the same manner as in the second catalyst of Example 1. It was calcined to prepare a second catalyst which supported 4.5% by weight (in terms of a metal element) of a copper oxide with respect to titania.
【0064】上記第二の触媒と実施例1で調製した第三
の触媒を重量比が20:1になるように混合してスラリ
ー化した後、実施例1と同じ方法でハニカム成形体に
0.26gの混合触媒をコートし、乾燥、焼成を行い、
銅、白金系浄化材(第二、第三の触媒をコートした浄化
材)を調製した。The second catalyst and the third catalyst prepared in Example 1 were mixed at a weight ratio of 20: 1 to form a slurry. .26 g of the mixed catalyst was coated, dried and calcined,
Copper and platinum-based purifying materials (purifying materials coated with second and third catalysts) were prepared.
【0065】反応管内の排ガスの流入側に実施例1の銀
系浄化材、流出側に銅、白金系浄化材をそれぞれセット
した。実施例1と同様の反応条件(銀系浄化材と銅、白
金系浄化材の見かけ空間速度はそれぞれ約80,000
h-1である)で、表1に示す組成のガスを用いて評価を
行った。結果を表2に示す。The silver purifying material of Example 1 was set on the inflow side of the exhaust gas in the reaction tube, and the copper and platinum purifying materials were set on the outflow side. The same reaction conditions as in Example 1 (the apparent space velocities of the silver-based purifying material, the copper-based purifying material and the platinum-based purifying material were about 80,000, respectively)
h- 1 ), the evaluation was performed using a gas having a composition shown in Table 1. Table 2 shows the results.
【0066】比較例1 実施例1で調製した銀系浄化材を排ガスの流入側に、実
施例1で調製した第三の触媒0.26gを実施例1と同
じ方法でハニカム成形体にコートした白金浄化材を排ガ
スの流出側にそれぞれセットした。実施例1と同様の反
応条件(銀系浄化材と白金系浄化材の見かけ空間速度は
それぞれ約80,000h-1である)で、表1に示す組
成のガスを用いて評価を行った。結果を表2に示す。 Comparative Example 1 A honeycomb molded body was coated with the silver-based purifying material prepared in Example 1 on the inflow side of the exhaust gas and 0.26 g of the third catalyst prepared in Example 1 in the same manner as in Example 1. A platinum purifying material was set on each of the exhaust gas outflow sides. Evaluation was carried out under the same reaction conditions as in Example 1 (the apparent space velocities of the silver-based purifying material and the platinum-based purifying material were respectively about 80,000 h -1 ) and the gases having the compositions shown in Table 1. Table 2 shows the results.
【0067】 表2 窒素酸化物(NOx)の除去率 窒素酸化物の除去率(%) 反応温度(℃) 300 350 400 450 500 実施例1 65.2 78.5 82.7 82.5 76.6 実施例2 63.4 75.8 82.1 85.9 78.8 実施例3 64.1 74.5 81.7 89.6 77.2 実施例4 69.8 78.7 82.8 89.1 76.6 実施例5 45.4 64.5 75.4 78.3 74.3 比較例1 20.5 32.5 38.7 42.6 40.5Table 2 Removal rate of nitrogen oxides (NOx) Removal rate of nitrogen oxides (%) Reaction temperature (° C.) 300 350 400 450 500 Example 1 65.2 78.5 82.7 82.5 76.6 Example 2 63.4 75.8 82.1 85.9 78.8 Execution Example 3 64.1 74.5 81.7 89.6 77.2 Example 4 69.8 78.7 82.8 89.1 76.6 Example 5 45.4 64.5 75.4 78.3 74.3 Comparative Example 1 20.5 32.5 38.7 42.6 40.5
【0068】表2からわかるように、銀、白金触媒だけ
を用いた比較例1に比べて、実施例1〜5は広い排ガス
温度領域で窒素酸化物の良好な除去がみられた。As can be seen from Table 2, in Examples 1 to 5, good removal of nitrogen oxides was observed in a wide exhaust gas temperature range as compared with Comparative Example 1 using only silver and platinum catalysts.
【0069】[0069]
【発明の効果】以上詳述したように、本発明の排ガス浄
化材を用いれば、広い温度領域において過剰の酸素を含
む排ガス中の窒素酸化物を効率良く除去することができ
る。本発明の排ガス浄化材及び浄化方法は、各種燃焼
機、自動車等の排ガス浄化に広く利用することができ
る。As described above in detail, the use of the exhaust gas purifying material of the present invention makes it possible to efficiently remove nitrogen oxides in exhaust gas containing excess oxygen in a wide temperature range. INDUSTRIAL APPLICABILITY The exhaust gas purifying material and the purification method of the present invention can be widely used for purifying exhaust gas of various types of combustors, automobiles and the like.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 FI 技術表示箇所 B01J 27/053 B01J 27/08 A 27/08 27/18 A 27/18 29/072 A 29/072 29/076 A 29/076 B01D 53/36 102H 104A ZAB (72)発明者 入手 直子 埼玉県熊谷市末広四丁目14番1号 株式 会社リケン熊谷事業所内 (72)発明者 吉田 清英 埼玉県熊谷市末広四丁目14番1号 株式 会社リケン熊谷事業所内 審査官 野田 直人 (56)参考文献 特開 平6−327942(JP,A) 特開 平6−319997(JP,A) 特開 平6−238166(JP,A)──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. 6 Identification number Agency reference number FI Technical indication location B01J 27/053 B01J 27/08 A 27/08 27/18 A 27/18 29/072 A 29 / 072 29/076 A 29/076 B01D 53/36 102H 104A ZAB (72) Acquisition of Inventor Naoko 4-1-1, Suehiro, Kumagaya-shi, Saitama Pref. RIKEN Kumagaya Plant (72) Inventor Kiyohide Yoshida Kumagaya, Saitama 4-14-1, Suehiro, Ichino Examiner, Naoto Noda, Rikken Kumagaya Works Co., Ltd. (56) References JP-A-6-327942 (JP, A) JP-A-6-319997 (JP, A) JP-A-6-319 238166 (JP, A)
Claims (8)
び/又は銀化合物、又はそれらの混合物0.2〜15重
量%(銀元素換算値)を担持してなる第一の触媒と、多
孔質の無機酸化物に活性種として銅の酸化物及び/又は
硫酸塩0.2〜30重量%(銅元素換算値)を担持して
なる第二の触媒と、多孔質の無機酸化物に活性種として
Pt、Pd、Ru、Rh、Ir及びAuからなる群より選ばれた少な
くとも1種の元素0.01〜5重量%(金属元素換算
値)を担持してなる第三の触媒とからなる排ガス浄化材
において、前記第一の触媒が排ガス流入側に面し、前記
第二の触媒と前記第三の触媒とを混合してなる混合触媒
が排ガス流出側に面することを特徴とする排ガス浄化
材。1. A first catalyst comprising a porous inorganic oxide carrying silver and / or a silver compound or a mixture thereof as an active species in an amount of 0.2 to 15% by weight (in terms of silver element), A second catalyst comprising a porous inorganic oxide supporting copper oxide and / or sulfate as an active species in an amount of 0.2 to 30% by weight (in terms of a copper element); As active species
Exhaust gas purification comprising a third catalyst carrying at least one element selected from the group consisting of Pt, Pd, Ru, Rh, Ir and Au in an amount of 0.01 to 5% by weight (in terms of a metal element). The exhaust gas purifying material, wherein the first catalyst faces the exhaust gas inflow side, and the mixed catalyst obtained by mixing the second catalyst and the third catalyst faces the exhaust gas outflow side. .
び/又は銀化合物、又はそれらの混合物0.2〜15重
量%(銀元素換算値)を担持してなる第一の触媒と、多
孔質の無機酸化物に活性種として銅の酸化物及び/又は
硫酸塩0.2〜30重量%(銅元素換算値)と、W、
V、Moからなる群より選ばれた少なくとも一種の元素
の酸化物又は硫酸塩30重量%以下(金属元素換算値)
とを担持してなる第二の触媒と、多孔質の無機酸化物に
活性種としてPt、Pd、Ru、Rh、Ir及びAuからなる群より
選ばれた少なくとも1種の元素0.01〜5重量%(金
属元素換算値)を担持してなる第三の触媒とからなる排
ガス浄化材において、前記第一の触媒が排ガス流入側に
面し、前記第二の触媒と前記第三の触媒とを混合してな
る混合触媒が排ガス流出側に面することを特徴とする排
ガス浄化材。2. A first catalyst comprising a porous inorganic oxide carrying as active species silver and / or a silver compound or a mixture thereof in an amount of 0.2 to 15% by weight (in terms of silver element), 0.2-30% by weight of copper oxide and / or sulfate as active species in the porous inorganic oxide (in terms of copper element);
30% by weight or less of oxide or sulfate of at least one element selected from the group consisting of V and Mo (converted value of metal element)
And at least one element selected from the group consisting of Pt, Pd, Ru, Rh, Ir and Au as active species on the porous inorganic oxide. In an exhaust gas purifying material comprising a third catalyst supporting the catalyst by weight (in terms of a metal element), the first catalyst faces the exhaust gas inflow side, and the second catalyst and the third catalyst An exhaust gas purifying material, characterized in that a mixed catalyst obtained by mixing the components faces the exhaust gas outflow side.
おいて、前記第二の触媒と第三の触媒の重量比は10
0:1〜100:50であることを特徴とする排ガス浄
化材。3. The exhaust gas purifying material according to claim 1, wherein the weight ratio of the second catalyst to the third catalyst is 10%.
An exhaust gas purifying material having a ratio of 0: 1 to 100: 50.
浄化材において、前記第一、第二、及び第三の触媒の内
の一つ以上がセラッミクス製又は金属製の基体の表面に
コートされたものであることを特徴とする排ガス浄化
材。4. The exhaust gas purifying material according to claim 1, wherein at least one of the first, second, and third catalysts is on a surface of a ceramic or metal substrate. An exhaust gas purifying material characterized by being coated.
浄化材において、前記第一、第二、及び第三の触媒の内
の一つ以上がペレット状又は顆粒状であることを特徴と
する排ガス浄化材。5. The exhaust gas purifying material according to claim 1, wherein at least one of the first, second, and third catalysts is in the form of pellets or granules. Exhaust gas purifying material.
浄化材において、前記銀化合物は銀の酸化物、ハロゲン
化銀、硫酸銀及び燐酸銀からなる群より選ばれた少なく
とも一種であることを特徴とする排ガス浄化材。6. The exhaust gas purifying material according to claim 1, wherein the silver compound is at least one selected from the group consisting of silver oxide, silver halide, silver sulfate and silver phosphate. An exhaust gas purifying material characterized by that:
浄化材において、前記多孔質無機酸化物が、第一の触媒
ではアルミナ、チタニアのいずれか又はそれらを含む複
合酸化物、第二の触媒ではアルミナ、チタニア及びゼオ
ライトのいずれか又はそれらを含む複合酸化物又はそれ
らの混合酸化物、第三の触媒ではアルミナ、チタニア、
ジルコニア、シリカ、ゼオライトからなる群より選ばれ
た一種以上の酸化物であることを特徴とする排ガス浄化
材。7. The exhaust gas purifying material according to claim 1, wherein the porous inorganic oxide is selected from the group consisting of alumina and titania or a composite oxide containing them in the first catalyst. In the catalyst of alumina, titania and zeolite, or a composite oxide containing them or a mixed oxide thereof, and in the third catalyst alumina, titania,
An exhaust gas purifying material comprising at least one oxide selected from the group consisting of zirconia, silica, and zeolite.
浄化材を用い、窒素酸化物と、共存する未燃焼成分に対
する理論反応量より多い酸素とを含む燃焼排ガスから窒
素酸化物を還元除去する排ガス浄化方法において、前記
排ガス浄化材を排ガス導管の途中に設置し、前記浄化材
の上流側で炭化水素及び/又は含酸素有機化合物を添加
した排ガスを、150〜600℃において前記浄化材に
接触させ、もって前記排ガス中の炭化水素及び/又は含
酸素有機化合物との反応により前記窒素酸化物を除去す
ることを特徴とする排ガス浄化方法。8. The method for reducing nitrogen oxides from a combustion exhaust gas containing the nitrogen oxides and oxygen in an amount larger than the theoretical reaction amount for the co-existing unburned components, using the exhaust gas purifying material according to any one of claims 1 to 7. In the exhaust gas purifying method for removing, the exhaust gas purifying material is installed in the middle of an exhaust gas conduit, and the exhaust gas to which a hydrocarbon and / or an oxygen-containing organic compound is added at an upstream side of the purifying material is subjected to the purifying material at 150 to 600 ° C. Exhaust gas purifying method, wherein the nitrogen oxides are removed by contact with a hydrocarbon and / or an oxygen-containing organic compound in the exhaust gas.
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6301478A JP2649217B2 (en) | 1994-11-10 | 1994-11-10 | Exhaust gas purifying material and exhaust gas purifying method |
EP95307871A EP0710499A3 (en) | 1994-11-04 | 1995-11-03 | Exhaust gas cleaner and method for cleaning exhaust gas |
US08/883,082 US5882607A (en) | 1994-11-04 | 1997-06-26 | Exhaust gas cleaner and method for cleaning exhaust gas |
US08/890,641 US5780002A (en) | 1994-11-04 | 1997-07-09 | Exhaust gas cleaner and method for cleaning exhaust gas |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6301478A JP2649217B2 (en) | 1994-11-10 | 1994-11-10 | Exhaust gas purifying material and exhaust gas purifying method |
Publications (2)
Publication Number | Publication Date |
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JPH08131778A JPH08131778A (en) | 1996-05-28 |
JP2649217B2 true JP2649217B2 (en) | 1997-09-03 |
Family
ID=17897394
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JP6301478A Expired - Lifetime JP2649217B2 (en) | 1994-11-04 | 1994-11-10 | Exhaust gas purifying material and exhaust gas purifying method |
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- 1994-11-10 JP JP6301478A patent/JP2649217B2/en not_active Expired - Lifetime
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