JPH06142515A - Catalyst for decomposing nitrous oxide - Google Patents

Catalyst for decomposing nitrous oxide

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Publication number
JPH06142515A
JPH06142515A JP4350071A JP35007192A JPH06142515A JP H06142515 A JPH06142515 A JP H06142515A JP 4350071 A JP4350071 A JP 4350071A JP 35007192 A JP35007192 A JP 35007192A JP H06142515 A JPH06142515 A JP H06142515A
Authority
JP
Japan
Prior art keywords
catalyst
aqueous solution
ai2o3
alpha
spherical
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.)
Pending
Application number
JP4350071A
Other languages
Japanese (ja)
Inventor
Masafumi Yoshimoto
雅文 吉本
Tadao Nakatsuji
忠夫 仲辻
Kazuhiko Nagano
一彦 永野
Kenji Nakahira
健二 中平
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sakai Chemical Industry Co Ltd
Original Assignee
Sakai Chemical Industry Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sakai Chemical Industry Co Ltd filed Critical Sakai Chemical Industry Co Ltd
Priority to JP4350071A priority Critical patent/JPH06142515A/en
Publication of JPH06142515A publication Critical patent/JPH06142515A/en
Pending legal-status Critical Current

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  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Catalysts (AREA)

Abstract

PURPOSE:To enhance decomposition efficiency and durability in the catalyst for exhaust gas of an automobile by making one kind selected from ruthenium and rhodium and at least one kind selected from among La2O3, CeO2, Pr2O3, Nd2O3, Sm2O3, Tb2O3 and Y2O3 carried on alpha-AI2O3. CONSTITUTION:At least one kind selected from ruthenium and rhodium and at least one kind selected from among La2O3, CeO2, Pr2O3, Nd2O3, Sm2O3, Tb2O3 and Y2O3 are carried on alpha-AI2O3. The catalyst is produced as follows. alpha-AI2O3 is immersed in the chloride aqueous solution of ruthenium and rhodium and impregnated with the noble metal. alpha-AI2O3 is dried and thereafter immersed in the aqueous solution of nitrates selected from among La, Ce, Pr, Nd, Sm, Tb and Y nitrates and impregnated with the precursor of oxide thereof, dried and thereafter burned. Furthermore reducing treatment is performed in H2 flow.

Description

【発明の詳細な説明】Detailed Description of the Invention

【産業上の利用分野】本発明は、排ガス中の窒素酸化
物、とりわけ亜酸化窒素（Ｎ２Ｏ）の分解除去用触媒に
係わり、詳しくは工場、自動車、ゴミ焼却炉、下水汚泥
焼却炉などの廃棄物処理設備などから排出される排気ガ
ス中に含まれる亜酸化窒素を分解除去する際に用いる好
適な窒素酸化物分解用触媒に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst for decomposing and removing nitrogen oxides in exhaust gas, particularly nitrous oxide (N 2 O), and more specifically, factories, automobiles, refuse incinerators, sewage sludge incinerators, etc. The present invention relates to a suitable catalyst for decomposing nitrogen oxides, which is used when decomposing and removing nitrous oxide contained in exhaust gas discharged from the waste treatment facility.

【従来の技術及び発明が解決しようとする課題】多種の
排ガス中の窒素酸化物（以下、ＮＯｘ）は、健康に有害
であり、かつ光化学スモッグや酸性雨の発生原因ともな
りうるため、その排出は厳しく制限されており、その効
果的な除去手段の開発が望まれている。ところで、従来
排出規制が義務づけられている窒素酸化物は主として一
酸化窒素（ＮＯ）及び二酸化窒素（ＮＯ２）である。こ
れらＮＯｘの除去方法としては、触媒を用いて排ガス中
のＮＯｘを低減する方法が既にいくつか実用化されてい
る。例えば（イ）ガソリン自動車における三元触媒法
や、（ロ）ボイラー等の大型設備排出源からの排ガスに
ついて、アンモニアを用いる選択的接触還元法が挙げら
れる。また、最近では（ハ）炭化水素を用いた排ガス中
のＮＯｘ除去方法として、銅等の金属を担持したゼオラ
イト、あるいはアルミナ等の金属酸化物を触媒として炭
化水素の共存下でＮＯを含むガスと接触させる方法など
が提案されるている。ところが、こうした方法ではいず
れも、排ガス中のＮ２Ｏの処理は不可能ではないが十分
ではなく、従来これらは、前述した脱硝設備の後流に未
処理のまま排出されてきた。これは、これまでＮ２Ｏに
対する法的な規制値がなく、又、ＪＩＳのような公的な
測定方法も定められてなかったことなどとも関連してお
り、実質的にはこれらの処理は、脱硝の対象としては黙
視されてきたというのが現実であった。ところが、前述
した脱硝方法においては、その運転条件によってＮ２Ｏ
が生成することが認められており、又、最近ではゴミ焼
却炉や下水汚泥焼却炉などからも比較的高濃度のＮ２Ｏ
が生成することも報告されている。加えて近年、Ｎ２Ｏ
は、ＣＯ２、フロン、ＣＨ４等とともに、成層圏でのオ
ゾ層の破壊、ないしは温室効果による温度上昇などもた
らす地球規模的汚染物質として特に注目されてきてい
る。こうした事情からＮ２Ｏの処理方法、とりわけその
分解触媒についての関心が高まっており、いくつかの方
法が提案されてきた。それらは例えば、ゼオライト系の
担体に各種の遷移金属を担持させたものあるいは又、酸
化マグネシウムや酸化亜鉛などの塩基性担体に各種の遷
移金属を担持させたものである。しかしながらこれらは
いずれも活性を示す温度が高く、低温では充分なる性能
が得られず、又処理ガス中に水分があるとその影響を強
く受けて失活するなどの弱点を有していた。こうした問
題を解決するため、既に本発明者らは、疎水性担体にル
テニウムあるいはロジウムをはじめとする種々の貴金属
を担持するなどの方法（平成４年５月２６日）、及びα
−Ａｌ２Ｏ３にルテニウムあるいはロジウムをはじめと
する種々の貴金属を担持するなどの方法（平成４年１０
月２２日）を出願している。しかしながら、こうした方
法によっても、貴金属のうちでＲｕやＲｈは、初期的に
は非常に高活性を示すものの反応中に経時的変化し、活
性の低下をもたらすなどの弱点を有することも明らかに
なった。本発明はこうした状況に鑑みてなされたもので
あり、その目的とするところは、排ガス中のＮ２Ｏを効
率よく分解することが出来ると同時耐久性の優れたＮ２
Ｏ分解用触媒を提供することにある。2. Description of the Related Art Nitrogen oxides (hereinafter referred to as NOx) in various kinds of exhaust gas are harmful to health and may cause photochemical smog and acid rain, so their emission Is severely limited, and the development of effective removal means is desired. By the way, the nitrogen oxides conventionally required to be emission regulated are mainly nitric oxide (NO) and nitrogen dioxide (NO 2 ). As methods for removing these NOx, some methods for reducing NOx in exhaust gas using a catalyst have already been put into practical use. For example, (a) a three-way catalyst method in a gasoline automobile, and (b) a selective catalytic reduction method using ammonia for exhaust gas from a large facility emission source such as a boiler. Recently, as a method for removing NOx in exhaust gas using (c) hydrocarbons, zeolite containing a metal such as copper, or a gas containing NO in the presence of hydrocarbons using a metal oxide such as alumina as a catalyst is used. Methods such as contacting have been proposed. However, none of these methods is not sufficient, but not sufficient, to treat N 2 O in the exhaust gas, and conventionally, these have been discharged untreated in the downstream of the above-mentioned denitration equipment. This is related to the fact that there is no legal regulation value for N 2 O and no official measurement method such as JIS has been established so far. However, the reality is that they have been ignored as targets for denitration. However, in the above-described denitration method, N 2 O may be added depending on the operating conditions.
It has been confirmed that methane is generated, and recently, a relatively high concentration of N 2 O has been obtained from garbage incinerators and sewage sludge incinerators.
Are also reported to be generated. In addition, in recent years, N 2 O
Has attracted particular attention as a global pollutant that causes destruction of the Ozo layer in the stratosphere, or temperature rise due to the greenhouse effect, together with CO 2 , chlorofluorocarbon, CH 4, and the like. Under such circumstances, there has been increasing interest in N 2 O treatment methods, particularly decomposition catalysts thereof, and several methods have been proposed. They are, for example, a zeolite-based carrier on which various transition metals are supported, or a basic carrier such as magnesium oxide or zinc oxide on which various transition metals are supported. However, all of them have a high temperature at which they are active, and they do not provide sufficient performance at low temperatures, and have a weak point that they are strongly affected by the presence of water in the process gas and are deactivated. In order to solve these problems, the present inventors have already carried out a method of loading various noble metals such as ruthenium or rhodium on a hydrophobic carrier (May 26, 1992), and α
-A method of supporting various noble metals such as ruthenium or rhodium on Al 2 O 3 ( 1992 1992 )
(May 22) is applied. However, even by such a method, it was revealed that among the noble metals, Ru and Rh have extremely weak activities in the initial stage, but change over time during the reaction, resulting in a decrease in activity. It was The present invention has been made in view of these circumstances, N 2 and has as its object, with excellent co-durability when it is possible to decompose efficiently N 2 O in the exhaust gas
It is to provide a catalyst for O decomposition.

【問題を解決するための手段】上記目的を達成するため
の本発明に係る亜酸化窒素分解用触媒は、α−Ａｌ２Ｏ
３に、（ａ）ルテニウム（Ｒｕ）、ロジウム（Ｒｈ）か
ら選ばれる少なくとも１種以上の貴金属、及び（ｂ）Ｌ
ａ２Ｏ３、ＣｅＯ２、Ｐｒ２Ｏ３、Ｎｄ２Ｏ３、Ｓｍ２
Ｏ３、Ｔｂ２Ｏ３、Ｙ２Ｏ３から選ばれる少なくとも１
種以上の貴金属を担持させてなる。本発明に係るα−Ａ
ｌ２Ｏ３としては、例えば不二見インコーポレイテッド
（株）の球状α−Ａｌ２Ｏ３、ＡＭ−Ｓ３１、ＡＭ−Ｓ
３２、ＡＭ−Ｓ３３、ＡＭ−Ｓ３４及び、住友化学
（株）製の粉状α−Ａｌ２Ｏ３、Ａ−２６、ＡＭＳ−
２、ＡＭＳ−９、ＡＭＳ−１２などを例示することが出
来る。あるいは又、住友化学（株）製の球状活性アルミ
ナＫＨＤ−２４（−４６）、同ＮＫＨＤ−２４（−４
６）などを１２００℃〜１３００℃で４〜５時間焼成す
ることによっても得ることが出来る。本発明に係る触媒
は、例えば以下の方法により調製することが出来る。前
述したα−Ａｌ２Ｏ３を、ＲｕあるいはＲｈなどの塩化
物の水溶液中に一定時間浸漬させ、これら貴金属を含浸
し、乾燥した後更に、硝酸ランタン、硝酸第一セリウ
ム、硝酸プラセオジウム、硝酸ネオジウム、硝酸サマリ
ウム、硝酸テルビウム、硝酸イットリウムなどの水溶液
中に一定時間浸漬させ、これら酸化物の前駆体を含浸
し、乾燥後、３００℃〜５００℃で３〜５時間焼成し、
更にＨ２気流中で４００℃〜５００℃で３〜５時間還元
処理をする。以上のようにして、本発明に係る触媒が得
られるが、これら貴金属の好適な担持量は、金属として
０．３〜２ｗｔ％である。０．３ｗｔ％以下では、これ
らの効果が十分に発揮されず、又２ｗｔ％を超えてもそ
れに見合うだけの活性の向上は得られなかった。又、Ｌ
ａ２Ｏ３、ＣｅＯ２、Ｐｒ２Ｏ３、Ｎｄ２Ｏ３、Ｓｍ２
Ｏ３、Ｔｂ２Ｏ３、Ｙ２Ｏ３などの酸化物の好適な担持
量は、酸化物として５〜２０ｗｔ％である。５ｗｔ％以
下では、これらの効果が十分に発揮されず、又２０ｗｔ
％を越えると担体の疎水性の低下をもたらし好ましくな
い。本発明に係る亜酸化窒素分解用触媒は、従来公知の
成形方法により、ハニカム状球状等の種々の形状に成形
することが出来る。さらに又、前述したα−Ａｌ２Ｏ３
のみを成形し、貴金属などを成形後に含浸させてもよ
い。さらに又、別に成形したセラミックス担体あるいは
セラミックファイバー製基材、コージエライト製ハニカ
ム等の上に前述した触媒粉をウォッシュコートしてもよ
い。又、成形の際には、成形助剤、無機繊維、有機バイ
ンダー等を適宜配合してもよい。本発明に係る亜酸化窒
素分解用触媒が、Ｎ２Ｏに対して活性を示す最適な温度
は、触媒種によって異なるが通常２００℃〜６００℃で
あり、この温度領域においては、空間速度（ＳＶ）５０
０〜５０００００程度で排ガスを通流させることが好ま
しい。なお、より好適な使用温度領域は３００℃〜５０
０℃である。The catalyst for decomposing nitrous oxide according to the present invention for achieving the above object is α-Al 2 O.
3 , (a) at least one or more noble metals selected from ruthenium (Ru) and rhodium (Rh), and (b) L
a 2 O 3, CeO 2, Pr 2 O 3, Nd 2 O 3, Sm 2
At least 1 selected from O 3 , Tb 2 O 3 , and Y 2 O 3.
It carries at least one precious metal. Α-A according to the present invention
Examples of l 2 O 3 include spherical α-Al 2 O 3 , AM-S31, and AM-S manufactured by Fujimi Incorporated.
32, AM-S33, AM-S34, and powdery α-Al 2 O 3 , A-26, AMS- manufactured by Sumitomo Chemical Co., Ltd.
2, AMS-9, AMS-12, etc. can be illustrated. Alternatively, spherical activated alumina KHD-24 (-46), NKHD-24 (-4) manufactured by Sumitomo Chemical Co., Ltd.
It can also be obtained by firing 6) or the like at 1200 ° C to 1300 ° C for 4 to 5 hours. The catalyst according to the present invention can be prepared, for example, by the following method. The above-mentioned α-Al 2 O 3 is immersed in an aqueous solution of a chloride such as Ru or Rh for a certain period of time, impregnated with these noble metals, dried, and then further lanthanum nitrate, cerous nitrate, praseodymium nitrate, neodymium nitrate. , Samarium nitrate, terbium nitrate, yttrium nitrate, etc. for a certain period of time to immerse them in the precursor of these oxides, and after drying, calcining at 300 ° C to 500 ° C for 3 to 5 hours,
Further, reduction treatment is performed at 400 ° C. to 500 ° C. for 3 to 5 hours in an H 2 stream. As described above, the catalyst according to the present invention is obtained, and the preferable loading amount of these noble metals is 0.3 to 2 wt% as metal. When the amount is 0.3 wt% or less, these effects are not sufficiently exhibited, and even when the amount exceeds 2 wt%, the activity improvement corresponding to the effect cannot be obtained. Also, L
a 2 O 3, CeO 2, Pr 2 O 3, Nd 2 O 3, Sm 2
A suitable supported amount of oxides such as O 3 , Tb 2 O 3 and Y 2 O 3 is 5 to 20 wt% as oxides. If the amount is 5 wt% or less, these effects are not sufficiently exhibited,
When it exceeds%, the hydrophobicity of the carrier decreases, which is not preferable. The catalyst for decomposing nitrous oxide according to the present invention can be molded into various shapes such as a spherical shape by a conventionally known molding method. Furthermore, the aforementioned α-Al 2 O 3
It is also possible to mold only and impregnate a noble metal or the like after molding. Further, the above-mentioned catalyst powder may be wash-coated on a separately formed ceramic carrier, ceramic fiber base material, cordierite honeycomb, or the like. Further, at the time of molding, a molding aid, an inorganic fiber, an organic binder and the like may be appropriately mixed. The optimum temperature at which the catalyst for decomposing nitrous oxide according to the present invention exhibits activity with respect to N 2 O varies depending on the catalyst species, but is usually 200 ° C. to 600 ° C. In this temperature range, the space velocity (SV ) 50
It is preferable to let the exhaust gas flow at about 0-500000. A more suitable operating temperature range is 300 ° C to 50 ° C.
It is 0 ° C.

【実施例】以下、本発明を実施例に基づいてさらに詳細
に説明するが、本発明は下記実施例に何ら限定されるも
のではなく、その要旨を変更しない範囲において適宜変
更して実施することが可能なものである。 （Ｉ）、触媒の調製 実施例１ 粒径が２ｍｍ〜４ｍｍ、比表面積６．０ｍ２／ｇ、細孔
容積０．３３ｍｌ／ｇ、吸水率３３％の不二見インコー
ポレイテッド（株）製の球状α−Ａｌ２Ｏ３、ＡＭ−Ｓ
３４をＲｈＣｌ３水溶液中に浸漬し、Ｒｈとして１．５
ｗｔ％となるよう含浸した。余分な水分を吹きとばした
後、１００℃で２時間乾燥した。次にこのものを硝酸ラ
ンタン水溶液（Ｌａ（ＮＯ３）３・６Ｈ２Ｏ）に浸漬
し、Ｌａ２Ｏ３として５ｗｔ％となるように含浸した。
余分な水分を吹きとばした後、１００℃で２時間乾燥
し、さらに４００℃で２時間焼成した。次にこれらをＨ
２気流中で５００℃で２時間還元処理して、球状α−Ａ
ｌ２Ｏ３にＲｈを１．５ｗｔ％、Ｌａ２Ｏ３を５ｗｔ％
担持した触媒を得た。 実施例２ 実施例１において、ＲｈＣｌ３水溶液にかえて、ＲｕＣ
ｌ３水溶液とする以外は実施例１と同様にして、球状α
−Ａｌ２Ｏ３にＲｕを１．５ｗｔ％、Ｌａ２Ｏ３を５ｗ
ｔ％担持した触媒を得た。 実施例３ 実施例１において、ＲｈＣｌ３水溶液にかえて、ＲｕＣ
ｌ３水溶液とし、硝酸ランタン水溶液（Ｌａ（ＮＯ３）
３・６Ｈ２Ｏ）にかえて、硝酸第一セリウム水溶液（Ｃ
ｅ（ＮＯ３）３・ｎＨ２Ｏ）とする以外は実施例１と同
様にして、球状α−Ａｌ２Ｏ３にＲｕを１．５ｗｔ％、
ＣｅＯ２を５ｗｔ％担持した触媒を得た。 実施例４ 実施例１において、ＲｈＣｌ３水溶液にかえて、ＲｕＣ
ｌ３水溶液とし、硝酸ランタン水溶液（Ｌａ（ＮＯ３）
３・６Ｈ２Ｏ）にかえて、硝酸プラセオジウム水溶液
（Ｐｒ（ＮＯ３）３・６Ｈ２Ｏ）とする以外は実施例１
と同様にして、球状α−Ａｌ２Ｏ３にＲｕを１．５ｗｔ
％、Ｐｒ２Ｏ３を５ｗｔ％担持した触媒を得た。 実施例５ 実施例１において、ＲｈＣｌ３水溶液にかえて、ＲｕＣ
ｌ３水溶液とし、硝酸ランタン水溶液（Ｌａ（ＮＯ３）
３・６Ｈ２Ｏ）にかえて、硝酸ネオジウム水溶液（Ｎｄ
（ＮＯ３）３・６Ｈ２Ｏ）とする以外は実施例１と同様
にして、球状α−Ａｌ２Ｏ３にＲｕを１．５ｗｔ％、Ｎ
ｄ２Ｏ３を５ｗｔ％担持した触媒を得た。 実施例６ 実施例１において、ＲｈＣｌ３水溶液にかえて、ＲｕＣ
ｌ３水溶液とし、硝酸ランタン水溶液（Ｌａ（ＮＯ３）
３・６Ｈ２Ｏ）にかえて、硝酸サマリウム水溶液（Ｓｍ
（ＮＯ３）３・６Ｈ２Ｏ）とする以外は実施例１と同様
にして、球状α−Ａｌ２Ｏ３にＲｕを１．５ｗｔ％、Ｓ
ｍ２Ｏ３を５ｗｔ％担持した触媒を得た。 実施例７ 実施例１において、ＲｈＣｌ３水溶液にかえて、ＲｕＣ
ｌ３水溶液とし、硝酸ランタン水溶液（Ｌａ（ＮＯ３）
３・６Ｈ２Ｏ）にかえて、硝酸テルビウム水溶液（Ｔｂ
（ＮＯ３）３・６Ｈ２Ｏ）とする以外は実施例１と同様
にして、球状α−Ａｌ２Ｏ３にＲｕを１．５ｗｔ％、Ｔ
ｂ２Ｏ３を５ｗｔ％担持した触媒を得た。 実施例８ 実施例１において、ＲｈＣｌ３水溶液にかえて、ＲｕＣ
ｌ３水溶液とし、硝酸ランタン水溶液（Ｌａ（ＮＯ３）
３・６Ｈ２Ｏ）にかえて、硝酸イットリウム水溶液（Ｙ
（ＮＯ３）３・６Ｈ２Ｏ）とする以外は実施例１と同様
にして、球状α−Ａｌ２Ｏ３にＲｕを１．５ｗｔ％、Ｙ
２Ｏ３を５ｗｔ％担持した触媒を得た。 実施例９ 実施例３において、硝酸第一セリウム水溶液（Ｃｅ（Ｎ
Ｏ３）３・６Ｈ２Ｏ）の濃度を２倍とする以外は、実施
例３と同様にして、球状α−Ａｌ２Ｏ３にＲｕを１．５
ｗｔ％、ＣｅＯ２を１０ｗｔ％担持した触媒を得た。 実施例１０ 実施例３において、硝酸第一セリウム水溶液（Ｃｅ（Ｎ
Ｏ３）３・６Ｈ２Ｏ）の濃度を３倍とする以外は、実施
例３と同様にして、球状α−Ａｌ２Ｏ３にＲｕを１．５
ｗｔ％、ＣｅＯ２を１５ｗｔ％担持した触媒を得た。 実施例１１ 平均粒子径が１．１μの住友化学（株）製の粉状α−Ａ
ｌ２Ｏ３、ＡＭＳ−２を水にリパルプした。このスラリ
ーにＣｅＯ２としてＡＭＳ−２に対して５ｗｔ％とする
ように、硝酸第一セリウム水溶液（Ｃｅ（ＮＯ３）２・
ｎＨ２Ｏ）を添加し、３０分間撹拌した。次いで（１＋
１）ＮＨ４ＯＨを用いてｐＨが８になるまで中和した。
このスラリーをろ別水洗、乾燥した後、５００℃で４時
間焼成し、ＣｅＯ２担持α−Ａｌ２Ｏ３パウダーを得
た。次にこのパウダーの１部をアルミナゾルをバインダ
ーとして、顆粒機にかけ篩を通して約１ｍｍの顆粒状物
とした。それにこれを核として、残りのパウダーを同じ
くアルミナゾルをバインダーとして転動造粒機にかけ、
篩を通して粒径が２ｍｍ〜４ｍｍの球状造物を得た。こ
れら造粒物は１００℃で５時間乾燥後さらに５００℃で
４時間焼成した。次いで、これをＲｕＣｌ３水溶液中に
浸漬し、Ｒｕとして１．５ｗｔ％となるように含浸し
た。余分な水分を吹きとばした後、１００℃で２時間焼
成した。次いで、これらをＨ２気流中で５００℃で２時
間還元処理をし、球状α−Ａｌ２Ｏ３にＲｕを１．５ｗ
ｔ％、ＣｅＯ２を５ｗｔ％担持した触媒を得た。 比較例１ 実施例１において、ＣｅＯ２を含浸担持せずして、Ｈ２
気流中、５００℃で２時間還元処理して、球状α−Ａｌ
２Ｏ３にＲｈのみを１．５ｗｔ％担持した触媒を得た。 比較例２ 実施例２において、ＣｅＯ２を含浸担持せずして、Ｈ２
気流中、５００℃で２時間還元処理して、球状α−Ａｌ
２Ｏ３にＲｕのみを１．５ｗｔ％担持した触媒を得た。 （ＩＩ）、評価試験 実施例１〜１１、比較例１〜２で得た触媒について、下
記の試験条件により、常圧流通式反応装置を用い、亜酸
化窒素含有ガスの接触分解を行い、反応開始１時間後、
１０時間後及び１００時間後の亜酸化窒素分解率を測定
した。尚、亜硝酸窒素分解率は、亜酸化窒素分のＮ２へ
の転換率をガスクロマトグラフ法によりＮ２を定量して
算出した。試験条件 、ガス組成 Ｎ２Ｏ ５０ｐｐｍ Ｏ２ ５％ Ｈ２Ｏ ２％ Ｈｅ 残部 、空間速度 ５０００Ｈｒ１ 、反応温度 ３５０℃ 結果を表１に示す。 EXAMPLES The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to the following examples, and various modifications may be made without departing from the scope of the invention. Is possible. (I), Preparation of Catalyst Example 1 Spherical particle made by Fujimi Incorporated Co., Ltd. having a particle size of 2 mm to 4 mm, a specific surface area of 6.0 m 2 / g, a pore volume of 0.33 ml / g and a water absorption rate of 33%. α-Al 2 O 3 , AM-S
34 was immersed in an aqueous solution of RhCl 3 to obtain Rh of 1.5.
It was impregnated so that it would be wt%. After blowing off excess water, it was dried at 100 ° C. for 2 hours. Next, this was immersed in a lanthanum nitrate aqueous solution (La (NO 3 ) 3 .6H 2 O) and impregnated with La 2 O 3 at 5 wt%.
After blowing off excess water, it was dried at 100 ° C. for 2 hours and further baked at 400 ° C. for 2 hours. Then these are H
Spherical α-A after reduction treatment at 500 ° C for 2 hours in 2 air streams
1.5 wt% Rh and 5 wt% La 2 O 3 in 1 2 O 3
A supported catalyst was obtained. Example 2 In Example 1, instead of the RhCl 3 aqueous solution, RuC was used.
except that the l 3 aqueous solution in the same manner as in Example 1, spherical α
-Al 2 O 3 with 1.5 wt% Ru and La 2 O 3 with 5 w
A catalyst supporting t% was obtained. Example 3 In Example 1, instead of the RhCl 3 aqueous solution, RuC was used.
and l 3 aqueous lanthanum nitrate solution (La (NO 3)
3 · 6H 2 O) in place, cerous nitrate solution (C
e (NO 3 ) 3 · nH 2 O) except that the spherical α-Al 2 O 3 is added with 1.5 wt% of Ru in the same manner as in Example 1.
A catalyst supporting 5 wt% of CeO 2 was obtained. Example 4 In Example 1, instead of the RhCl 3 aqueous solution, RuC was used.
and l 3 aqueous lanthanum nitrate solution (La (NO 3)
3 · 6H 2 O) in place, the embodiment except that the praseodymium nitrate aqueous solution (Pr (NO 3) 3 · 6H 2 O) 1
In the same manner as described above, 1.5 wt% of Ru was added to the spherical α-Al 2 O 3.
%, Pr 2 O 3 of 5 wt% was obtained. Example 5 In Example 1, instead of the RhCl 3 aqueous solution, RuC was used.
and l 3 aqueous lanthanum nitrate solution (La (NO 3)
3 · 6H 2 O) in place, neodymium nitrate aqueous solution (Nd
(NO 3) 3 · 6H 2 O) except that as in the same manner as in Example 1, 1.5 wt% of Ru in spherical α-Al 2 O 3, N
A catalyst supporting 5 wt% of d 2 O 3 was obtained. Example 6 In Example 1, instead of the RhCl 3 aqueous solution, RuC was used.
and l 3 aqueous lanthanum nitrate solution (La (NO 3)
3 · 6H 2 O) in place, samarium nitrate solution (Sm
(NO 3) 3 · 6H 2 O) except that as in the same manner as in Example 1, 1.5 wt% of Ru in spherical α-Al 2 O 3, S
A catalyst supporting 5 wt% of m 2 O 3 was obtained. Example 7 In Example 1, instead of the RhCl 3 aqueous solution, RuC was used.
and l 3 aqueous lanthanum nitrate solution (La (NO 3)
3 · 6H 2 O) in place, terbium nitrate aqueous solution (Tb
(NO 3) 3 · 6H 2 O) except that as in the same manner as in Example 1, 1.5 wt% of Ru in spherical α-Al 2 O 3, T
A catalyst supporting 5 wt% of b 2 O 3 was obtained. Example 8 In Example 1, instead of the RhCl 3 aqueous solution, RuC was used.
and l 3 aqueous lanthanum nitrate solution (La (NO 3)
3 · 6H 2 O) in place, yttrium nitrate solution (Y
(NO 3) 3 · 6H 2 O) except that as in the same manner as in Example 1, 1.5 wt% of Ru in spherical α-Al 2 O 3, Y
A catalyst supporting 5% by weight of 2 O 3 was obtained. Example 9 In Example 3, a cerium nitrate aqueous solution (Ce (N
O 3) 3 · 6H 2 O ) except that twice the concentration of, in the same manner as in Example 3, the Ru spherical alpha-Al 2 O 3 1.5
A catalyst supporting 10% by weight of CeO 2 was obtained. Example 10 In Example 3, a ceric nitrate aqueous solution (Ce (N
O 3) 3 · 6H 2 O ) except that the 3-fold the concentration of, in the same manner as in Example 3, the Ru spherical α-Al 2 O 3 1.5
A catalyst supporting wt% and CeO 2 of 15 wt% was obtained. Example 11 Powdered α-A manufactured by Sumitomo Chemical Co., Ltd. having an average particle diameter of 1.1 μm
I 2 O 3 and AMS-2 were repulped in water. CeO 2 was added to this slurry in an amount of 5 wt% with respect to AMS-2, and a ceric nitrate aqueous solution (Ce (NO 3 ) 2 ·.
nH 2 O) was added and stirred for 30 minutes. Then (1+
1) Neutralized with NH 4 OH until pH = 8.
The slurry was filtered, washed with water, dried, and then calcined at 500 ° C. for 4 hours to obtain CeO 2 -supporting α-Al 2 O 3 powder. Next, a part of this powder was passed through a granulator using alumina sol as a binder and passed through a sieve to give a granular material of about 1 mm. With this as the core, the rest of the powder was also tumbled with an alumina sol as a binder.
A spherical structure having a particle diameter of 2 mm to 4 mm was obtained through a sieve. These granules were dried at 100 ° C. for 5 hours and then calcined at 500 ° C. for 4 hours. Next, this was immersed in a RuCl 3 aqueous solution and impregnated with Ru to a concentration of 1.5 wt%. After blowing off excess water, it was baked at 100 ° C. for 2 hours. Next, these are subjected to reduction treatment in a H 2 stream at 500 ° C. for 2 hours, and spherical α-Al 2 O 3 is added with Ru of 1.5 w.
A catalyst supporting t% and CeO 2 at 5 wt% was obtained. Comparative Example 1 In Example 1, H 2 was added without CeO 2 being impregnated and supported.
Spherical α-Al after reduction treatment at 500 ° C for 2 hours in air flow
A catalyst was obtained in which only 2 wt% of Rh was supported on 2 O 3 . Comparative Example 2 In Example 2, H 2 was added without CeO 2 being impregnated and supported.
Spherical α-Al after reduction treatment at 500 ° C for 2 hours in air flow
A catalyst was obtained in which only Ru was supported on 2 O 3 by 1.5 wt%. (II), Evaluation Test Regarding the catalysts obtained in Examples 1 to 11 and Comparative Examples 1 to 2, catalytic decomposition of nitrous oxide-containing gas was carried out by reaction under the following test conditions using a normal pressure flow reactor. 1 hour after the start
The nitrous oxide decomposition rate after 10 hours and 100 hours was measured. Incidentally, nitrite nitrogen decomposition rate was calculated by quantifying the N 2 by gas chromatography a conversion to nitrous oxide content of N 2. Test conditions , gas composition N 2 O 50 ppm O 2 5% H 2 O 2% He balance, space velocity 5000 Hr 1 , reaction temperature 350 ° C. The results are shown in Table 1.

【発明の効果】以上詳細に説明したように、本発明に係
る亜酸化窒素分解用触媒は、排ガス中の亜酸化窒素を効
率よく接触分解することが出来ると同時に、経時変化を
しにくいなど、優れた特有の効果を有する。As described in detail above, the catalyst for decomposing nitrous oxide according to the present invention is capable of efficiently catalytically decomposing nitrous oxide in exhaust gas and, at the same time, is unlikely to change with time. It has an excellent unique effect.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 中平 健二 大阪府堺市戎島町５丁１番地 堺化学工業 株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Nakahira 5-1, Ebishimacho, Sakai City, Osaka Prefecture Sakai Chemical Industry Co., Ltd.

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】α−Ａｌ２Ｏ３に、（ａ）ルテニウム（Ｒ
ｕ）、ロジウム（Ｒｈ）から選ばれる少なくとも１
種、、及び（ｂ）Ｌａ２Ｏ３、ＣｅＯ２、Ｐｒ２Ｏ３、
Ｎｄ２Ｏ３、Ｓｍ２Ｏ３、Ｔｂ２Ｏ３、Ｙ２Ｏ３から選
ばれる少なくとも１種を担持することを特徴とする亜酸
化窒素分解用触媒。1. (a) Ruthenium (R) is added to α-Al 2 O 3.
u), at least 1 selected from rhodium (Rh)
Seeds, and (b) La 2 O 3 , CeO 2 , Pr 2 O 3 ,
A catalyst for decomposing nitrous oxide, which carries at least one selected from Nd 2 O 3 , Sm 2 O 3 , Tb 2 O 3 , and Y 2 O 3 .
JP4350071A 1992-11-12 1992-11-12 Catalyst for decomposing nitrous oxide Pending JPH06142515A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4350071A JPH06142515A (en) 1992-11-12 1992-11-12 Catalyst for decomposing nitrous oxide

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4350071A JPH06142515A (en) 1992-11-12 1992-11-12 Catalyst for decomposing nitrous oxide

Publications (1)

Publication Number Publication Date
JPH06142515A true JPH06142515A (en) 1994-05-24

Family

ID=18408035

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4350071A Pending JPH06142515A (en) 1992-11-12 1992-11-12 Catalyst for decomposing nitrous oxide

Country Status (1)

Country Link
JP (1) JPH06142515A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007152263A (en) * 2005-12-07 2007-06-21 Nippon Shokubai Co Ltd Catalyst for nitrous oxide decomposition and method for purifying nitrous oxide-containing gas

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007152263A (en) * 2005-12-07 2007-06-21 Nippon Shokubai Co Ltd Catalyst for nitrous oxide decomposition and method for purifying nitrous oxide-containing gas
JP4672540B2 (en) * 2005-12-07 2011-04-20 株式会社日本触媒 Nitrous oxide decomposition catalyst and purification method of nitrous oxide-containing gas

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