JPH067641A - Material for removing nitrogen oxide and method for removing nitrogen oxide - Google Patents
Material for removing nitrogen oxide and method for removing nitrogen oxideInfo
- Publication number
- JPH067641A JPH067641A JP5021788A JP2178893A JPH067641A JP H067641 A JPH067641 A JP H067641A JP 5021788 A JP5021788 A JP 5021788A JP 2178893 A JP2178893 A JP 2178893A JP H067641 A JPH067641 A JP H067641A
- Authority
- JP
- Japan
- Prior art keywords
- oxide
- nitrogen oxide
- silver
- nitrogen
- oxygen
- 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
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
Landscapes
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Abstract
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除去する
ことのできる方法、及びそれに用いる窒素酸化物除去材
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for effectively removing nitrogen oxides from a combustion exhaust gas containing nitrogen oxides and excess oxygen, and a nitrogen oxide removing material used therefor.
【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（一般にNOx と呼ばれる）が含ま
れている。ここで、窒素酸化物とは一般に、一酸化窒素
及び／又は二酸化窒素を指し、また、「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。2. Description of the Related Art Excessive amounts of combustion exhaust gas discharged from internal combustion engines such as automobile engines, combustion equipment installed in factories, household fan heaters, etc. Nitrogen oxides (generally called NOx) such as nitric oxide and nitrogen dioxide are contained together with oxygen. Here, the nitrogen oxides generally refer to nitric oxide and / or nitrogen dioxide, and the phrase "containing excess oxygen" means carbon monoxide, hydrogen,
It is meant to contain more oxygen than the theoretical amount of oxygen required to burn unburned components such as hydrocarbons.
【０００３】このような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。Such nitrogen oxides are considered to be one of the causes of acid rain and have become a serious environmental problem. Therefore, various methods for removing nitrogen oxides in exhaust gas discharged from various combustion devices have been 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。As a method for removing nitrogen oxides from combustion exhaust gas containing excess oxygen, a selective catalytic reduction method using ammonia is used, particularly for large-scale fixed combustion devices (large combustors such as factories). It has been put to practical use.
【０００５】しかしながら、上記の方法においては、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、さらに装置が大型とな
ること等の問題点がある。However, in the above method, ammonia used as a reducing agent for nitrogen oxides is expensive, and the amount of injected ammonia is measured while measuring the nitrogen oxide concentration in the exhaust gas so that unreacted ammonia is not discharged. Must be controlled, and the size of the device must be 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。[0006] As another method, there is a non-selective catalytic reduction method for reducing nitrogen oxides by using a gas such as hydrogen, carbon monoxide or hydrocarbon as a reducing agent, but this method is effective. In order to reduce and remove nitrogen oxides, it is necessary to add a reducing agent in an amount equal to or larger than a theoretical reaction amount with oxygen in exhaust gas, and there is a drawback that a large amount of reducing agent is consumed. Therefore, the non-selective catalytic reduction method is practically effective only for the exhaust gas having a low residual oxygen concentration that is burned in the vicinity of the theoretical air-fuel ratio, and is not versatile and impractical.
【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、及び日本化学会第59春季年会
(1990年)2A526、同第60秋季年会 (1990年)3L420、3L42
2 、3L423 等) 。Therefore, there has been proposed a method for removing nitrogen oxides by adding a reducing agent in an amount equal to or less than a theoretical reaction amount with oxygen in exhaust gas by using zeolite or a catalyst supporting a transition metal thereon (for example, a special method). Kaisho 63-100919, 63-28372
No. 7, JP-A-1-130735, and 59th Annual Meeting of the Chemical Society of Japan
(1990) 2A526, 60th Autumn Meeting (1990) 3L420, 3L42
2, 3L423, etc.).
【０００８】しかしながら、これらの方法では、水分を
含まないような模擬排ガスに対しては高い効率で窒素酸
化物を除去することはできるが、実際の排ガスでは水分
を１０％程度含有するので、窒素酸化物の除去率が著し
く低下することがわかった。また、これらの方法では、
窒素酸化物の還元反応の最適温度が400 〜600 ℃程度と
比較的高くなる不都合もある。However, although these methods can remove nitrogen oxides with high efficiency from a simulated exhaust gas containing no water, the actual exhaust gas contains about 10% of water, so It was found that the oxide removal rate was significantly reduced. Also, with these methods,
There is also the disadvantage that the optimum temperature for the reduction reaction of nitrogen oxides is relatively high at around 400-600 ° C.
【０００９】また、メタノールを排ガス中に添加し、こ
のメタノール含有排ガスを３００℃程度でアルミナに接
触させ、窒素酸化物を低減する方法（「触媒」vol.33、
No.2、59ページ、1991年）も提案されているが、この方
法では窒素酸化物の低減特性が低く、実際的ではない。Further, a method of adding methanol to an exhaust gas and contacting the methanol-containing exhaust gas with alumina at about 300 ° C. to reduce nitrogen oxides (“Catalyst” vol.33,
No. 2, p. 59, 1991) has also been proposed, but this method is not practical because the nitrogen oxide reducing property is low.
【００１０】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
化物及び一酸化炭素、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
く窒素酸化物を除去することができる窒素酸化物除去
材、及び窒素酸化物除去方法を提供することである。Therefore, an object of the present invention is to provide unburned components such as nitrogen oxides, carbon monoxide, and hydrocarbons, such as combustion exhaust gas from a fixed combustion device and a gasoline engine, a diesel engine, etc. that burn under excess oxygen conditions. It is to provide a nitrogen oxide removing material and a nitrogen oxide removing method capable of efficiently removing nitrogen oxides from a combustion exhaust gas containing oxygen in an amount equal to or more than a theoretical reaction amount with respect to.
【００１１】[0011]
【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、多孔質の無機酸化物に銀又は銀酸
化物を担持した浄化材基材をSO2 で処理した除去材を用
い、炭素数が２以上の炭化水素、または、炭素原子を２
個以上、酸素原子を１個以上有する脂肪族含酸素有機化
合物を排ガス中の窒素酸化物の量に見合った量だけ添加
して、上記窒素酸化物除去材に所定の温度で接触させて
やれば、水分を１０％程度含有する排ガスであっても窒
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。As a result of earnest research in view of the above problems, the present inventor has found that a removal material obtained by treating a purification material base material in which silver or silver oxide is supported on a porous inorganic oxide with SO 2 is treated. Using a hydrocarbon having 2 or more carbon atoms or 2 carbon atoms
Or more and an aliphatic oxygen-containing organic compound having one or more oxygen atoms are added in an amount corresponding to the amount of nitrogen oxides in the exhaust gas, and contacted with the nitrogen oxide removing material at a predetermined temperature. It was discovered that nitrogen oxides can be effectively removed even with exhaust gas containing about 10% of water, and the present invention has been completed.
【００１２】すなわち、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除去する本発明の窒素酸化物除去材
は、多孔質の無機酸化物に銀又は銀酸化物を担持した浄
化材基材を、SO2 に接触させて処理したことを特徴とす
る。That is, the nitrogen oxide removing material of the present invention for removing nitrogen oxides from combustion exhaust gas containing nitrogen oxides and oxygen in an amount larger than the theoretical reaction amount for coexisting unburned components is a porous inorganic oxide. The purification material base material carrying silver or silver oxide is treated by contacting with SO 2 .
【００１３】また、上記の窒素酸化物除去材を用いて、
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除去
する本発明の方法は、炭素数が２以上の炭化水素の１種
以上、又は炭素原子を２個以上、酸素原子を１個以上有
する脂肪族含酸素有機化合物の１種以上を前記排ガスに
添加し、前記炭化水素又は前記脂肪族含酸素有機化合物
を添加した排ガスを前記窒素酸化物除去材に２００〜６
００℃で接触させることにより、前記窒素酸化物と、前
記炭化水素又は前記脂肪族含酸素有機化合物とを反応さ
せて前記窒素酸化物を除去することを特徴とする。Further, using the above nitrogen oxide removing material,
The method of the present invention for removing nitrogen oxides from a combustion exhaust gas containing nitrogen oxides and oxygen in a larger amount than the theoretical reaction amount for coexisting unburned components is one or more kinds of hydrocarbons having 2 or more carbon atoms, or carbon. The exhaust gas obtained by adding one or more kinds of aliphatic oxygen-containing organic compounds having two or more atoms and one or more oxygen atoms to the exhaust gas and adding the hydrocarbon or the aliphatic oxygen-containing organic compound to the nitrogen oxides 200 to 6 for removing material
The nitrogen oxide is removed by reacting the nitrogen oxide with the hydrocarbon or the aliphatic oxygen-containing organic compound by bringing them into contact with each other at 00 ° C.
【００１４】以下、本発明を詳細に説明する。本発明で
は、排ガス中に、炭素数が２以上の炭化水素、又は炭素
原子を２個以上、酸素原子を１個以上有する脂肪族含酸
素有機化合物の１種以上を添加し、これらの添加物質を
含有する排ガスを、多孔質の無機酸化物に銀又は銀酸化
物を担持した後にSO2 で処理してなる窒素酸化物除去材
に接触させ、排ガス中に添加した物質と排ガス中の窒素
酸化物とを反応させて窒素酸化物を除去する。The present invention will be described in detail below. In the present invention, hydrocarbons having 2 or more carbon atoms, or one or more kinds of aliphatic oxygen-containing organic compounds having 2 or more carbon atoms and 1 or more oxygen atoms are added to the exhaust gas, and these added substances are added. Exhaust gas containing is brought into contact with a nitrogen oxide removing material obtained by supporting silver or silver oxide on a porous inorganic oxide and then treating with SO 2 , and the substance added to the exhaust gas and the nitrogen oxidation in the exhaust gas. The substance is reacted to remove nitrogen oxides.
【００１５】まず、排ガスに添加した炭化水素又は脂肪
族含酸素有機化合物と排ガス中の窒素酸化物との反応サ
イトとなる除去材としては、多孔質の無機酸化物に銀又
は銀酸化物を担持し、これをSO2 に接触させて処理した
ものを用いる。First, as a removing material which becomes a reaction site between the hydrocarbon or the aliphatic oxygen-containing organic compound added to the exhaust gas and the nitrogen oxide in the exhaust gas, silver or silver oxide is supported on a porous inorganic oxide. Then, this is used after being treated by contacting with SO 2 .
【００１６】多孔質の無機酸化物としては、多孔質のア
ルミナ、チタニア、ジルコニア、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、又はアルミナ系複合酸化物を用いる。As the porous inorganic oxide, porous alumina, titania, zirconia, and their complex oxides can be used, but γ-alumina or alumina complex oxide is preferably used. .
【００１７】本発明では、上記したγ−アルミナ、アル
ミナ系複合酸化物等の無機酸化物に銀又は銀酸化物を担
持したものを浄化材基材とするが、銀又は銀酸化物の担
持量は、無機酸化物の重量の０．１〜１５重量％（元素
換算値）とするのが好ましい。銀又は銀酸化物の担持量
が上記範囲の下限値未満では、銀の担持による窒素酸化
物の除去効果が顕著とはならず、また、上限値を超す量
の銀を担持しても窒素酸化物の除去率の向上はみられな
い。より好ましくは、銀又は銀酸化物の担持量を無機酸
化物の重量の０．５〜１０重量％とする。In the present invention, the purifying material base material is prepared by carrying silver or silver oxide on the above-mentioned inorganic oxide such as γ-alumina and alumina-based composite oxide. Is preferably 0.1 to 15% by weight (elemental conversion value) of the weight of the inorganic oxide. When the supported amount of silver or silver oxide is less than the lower limit of the above range, the effect of removing nitrogen oxides by supporting silver is not remarkable, and even when the amount of silver exceeding the upper limit is supported, nitrogen oxidation is carried out. There is no improvement in the removal rate of objects. More preferably, the amount of silver or silver oxide supported is 0.5 to 10% by weight of the weight of the inorganic oxide.
【００１８】なお、無機酸化物への銀又は銀酸化物の担
持は、硝酸銀等の水溶液に上述した多孔質の無機酸化物
を浸漬し、７０℃程度で乾燥後、70〜550 ℃で段階的に
昇温して焼成することにより行うことができる。この焼
成を水素等の還元性ガス流通下で行った場合は、さら
に、酸素等の酸化性ガスを含む気流下で焼成した後、使
用することが望ましい。The supporting of silver or silver oxide on the inorganic oxide is carried out by immersing the above-mentioned porous inorganic oxide in an aqueous solution of silver nitrate, drying at about 70 ° C., and then stepwise at 70 to 550 ° C. It can be carried out by raising the temperature to 2, and firing. When this firing is carried out under the flow of a reducing gas such as hydrogen, it is desirable to further use it after firing under a stream of an oxidizing gas such as oxygen.
【００１９】上述した方法により多孔質の無機酸化物に
銀又は銀酸化物を担持した浄化材基材を得たら、次に、
これをSO2 ガスに接触させる。SO2 による浄化材基材の
処理では、多孔質の無機酸化物に銀又は銀酸化物を担持
してなる浄化材基材１ｇあたり、０．０２〜１mmolのSO
2 を接触させるのが好ましい。SO2 により処理してなる
浄化材を用いると、排ガス中の炭化水素（脂肪族含酸素
有機化合物を含む）が酸素により直接酸化されないで、
炭化水素（脂肪族含酸素有機化合物を含む）と窒素酸化
物との反応が良好に起こるものと思われる。When a purifying material base material in which silver or silver oxide is supported on a porous inorganic oxide is obtained by the above-mentioned method, then,
This is brought into contact with SO 2 gas. In the treatment of the purification material base material with SO 2 , 0.02 to 1 mmol of SO is added per 1 g of the purification material base material in which silver or silver oxide is supported on the porous inorganic oxide.
It is preferable to contact two . When using a purification material treated with SO 2 , hydrocarbons (including aliphatic oxygen-containing organic compounds) in exhaust gas are not directly oxidized by oxygen,
It seems that the reaction between hydrocarbons (including aliphatic oxygen-containing organic compounds) and nitrogen oxides occurs favorably.
【００２０】窒素酸化物除去材（銀又は銀酸化物を担持
したγ−アルミナ等の無機酸化物をSO2 で処理したも
の）は、ペレット状、粉末状、ハニカム状、フォーム
状、板状等の状態で、排ガス導管の途中に設置する。な
お、上述した除去材がペレット状や粉末状の場合には、
ケーシングに入れて排ガス導管の途中に設置するのが実
際的である。また、(a) 耐熱性に優れたコージェライト
やムライト、又は他のセラミック材、もしくは(b) 金属
からなるハニカム状やフォーム状の成形体（担体）の表
面に、銀又は銀酸化物を担持した粉末状の無機酸化物を
公知の方法（たとえばウォッシュコート法等）によりコ
ートしたり、又は無機酸化物を成形体にコートした後、
銀又は銀酸化物を担持し、これを上述した条件でSO2 に
より処理してもよい。The nitrogen oxide removing material (inorganic oxide such as γ-alumina carrying silver or silver oxide treated with SO 2 ) is used in the form of pellets, powder, honeycomb, foam, plate, etc. Install in the middle of the exhaust gas pipe in the state of. If the above-mentioned removing material is in the form of pellets or powder,
It is practical to put it in a casing and install it in the middle of the exhaust gas conduit. In addition, (a) cordierite or mullite having excellent heat resistance, or another ceramic material, or (b) a honeycomb-shaped or foam-shaped molded body (support) made of metal, carrying silver or silver oxide thereon. After coating the powdered inorganic oxide by a known method (for example, wash coating method) or coating the molded body with the inorganic oxide,
Silver or silver oxide supported, which may be treated by SO 2 under the conditions described above.
【００２１】窒素酸化物除去材を設置した部位で、炭化
水素又は脂肪族含酸素有機化合物と、窒素酸化物との反
応が生じるのであるから、排ガス中に炭化水素又は脂肪
族含酸素有機化合物を添加するのはこの除去材を設置し
た部位の上流側となる。Since a reaction between the hydrocarbon or the aliphatic oxygen-containing organic compound and the nitrogen oxide occurs at the site where the nitrogen oxide removing material is installed, the hydrocarbon or the aliphatic oxygen-containing organic compound is contained in the exhaust gas. It is added on the upstream side of the site where the removing material is installed.
【００２２】本発明では、炭素数が２以上の炭化水素、
又は炭素原子を２個以上、酸素原子を１個以上有する脂
肪族含酸素有機化合物を排ガスに添加する。脂肪族含酸
素有機化合物としては、アルコール、ケトン、アルデヒ
ド、カルボン酸、エーテル、エステル等が挙げられる。
アルコールは、炭素数が２以上の脂肪族の一価アルコー
ルである。この中では特に、エタノールやプロパノール
（ｎ−プロピルアルコール、イソプロピルアルコール）
等の比較的低分子量のアルコールを用いるのがよい。な
お、メタノールを用いると、窒素酸化物との反応が良好
に進行しない。また、ケトンとしては、特にアセトン等
を用いるのが好ましい。さらにカルボン酸としても、カ
ルボン酸中の炭素数（カルボキシル基の炭素を含む）が
２以上のものを用いる。特に、酢酸が好適である。アル
デヒドとしてはアセトアルデヒドが好ましい。In the present invention, a hydrocarbon having 2 or more carbon atoms,
Alternatively, an aliphatic oxygen-containing organic compound having two or more carbon atoms and one or more oxygen atoms is added to the exhaust gas. Examples of the aliphatic oxygen-containing organic compound include alcohols, ketones, aldehydes, carboxylic acids, ethers and esters.
The alcohol is an aliphatic monohydric alcohol having 2 or more carbon atoms. Among them, especially ethanol and propanol (n-propyl alcohol, isopropyl alcohol)
It is preferable to use a relatively low molecular weight alcohol such as. When methanol is used, the reaction with nitrogen oxide does not proceed well. As the ketone, it is particularly preferable to use acetone or the like. Further, as the carboxylic acid, one having 2 or more carbon atoms (including carbon of the carboxyl group) in the carboxylic acid is used. Acetic acid is particularly preferable. Acetaldehyde is preferred as the aldehyde.
【００２３】また、本発明では、添加した物質と窒素酸
化物との反応が起きる除去材の設置部位における排ガス
の温度を２００〜６００℃に保つ。排ガスの温度が２０
０℃未満であると添加した物質と窒素酸化物との反応特
性が低下し、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添加した物質
自身の燃焼が始まり、これらの物質の添加による窒素酸
化物の還元除去が効率良く行えない。なお、排ガス中に
添加する炭化水素や脂肪族含酸素有機化合物の種類によ
り、除去材近傍の排ガス温度を多少変化させるのが好ま
しい。Further, in the present invention, the temperature of the exhaust gas at the installation site of the removing material in which the reaction between the added substance and the nitrogen oxide occurs is maintained at 200 to 600 ° C. Exhaust gas temperature is 20
If the temperature is lower than 0 ° C, the reaction characteristics between the added substance and the nitrogen oxides are deteriorated, and the nitrogen oxides cannot be removed satisfactorily. On the other hand, if the temperature exceeds 600 ° C., the added substances themselves start to burn, and the nitrogen oxides cannot be reduced and removed efficiently by adding these substances. In addition, it is preferable to change the exhaust gas temperature in the vicinity of the removing material to some extent depending on the types of hydrocarbons and aliphatic oxygen-containing organic compounds added to the exhaust gas.
【００２４】[0024]
【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 市販のペレット状のγ−アルミナ約１０ｇ（直径1.5mm
、長さ約６mm）を硝酸銀水溶液に浸漬し、７０℃で乾
燥後、５容量％の水素を含む窒素気流下、１００℃、１
２５℃、１５０℃、及び２００℃で各２時間、次に３０
０℃で３０分焼成後、窒素ガスで水素をパージしてか
ら、水、炭酸ガス、酸素を各１０％含有する窒素気流
下、３００℃、４００℃、及び５００℃で各２時間、５
５０℃で５時間焼成し、γ−アルミナに対して２重量％
の銀（元素換算値）を担持したペレット状の浄化材基材
を得た。The present invention will be described in more detail by the following specific examples. Example 1 About 10 g of commercially available pelletized γ-alumina (diameter 1.5 mm
(About 6 mm in length) is immersed in an aqueous solution of silver nitrate, dried at 70 ° C., and then at 100 ° C. under a nitrogen stream containing 5% by volume of hydrogen, 1
2 hours each at 25 ° C, 150 ° C, and 200 ° C, then 30
After baking at 0 ° C. for 30 minutes, purging hydrogen with nitrogen gas, and then at 300 ° C., 400 ° C., and 500 ° C. for 2 hours each in a nitrogen stream containing water, carbon dioxide gas, and oxygen at 10% each.
2% by weight with respect to γ-alumina by firing at 50 ° C for 5 hours
Thus, a pellet-like purifying material base material carrying silver (elemental conversion value) was obtained.
【００２５】この浄化材基材（約１０ｇ）を３００℃
で、表１に示すガス組成にSO2 を添加したガス（SO2 ：
３７３ｐｐｍ）に１時間接触させて、SO2 ２mmolで処理
した窒素酸化物除去材を得た。This purifying material base material (about 10 g) is heated to 300 ° C.
Then, a gas obtained by adding SO 2 to the gas composition shown in Table 1 (SO 2 :
(373 ppm) for 1 hour to obtain a nitrogen oxide removing material treated with 2 mmol of SO 2 .
【００２６】得られた除去材を反応管に充填し、表１に
示す組成のガス（一酸化窒素、二酸化炭素、酸素、エタ
ノール、及び窒素からなる乾燥成分の合計１００容量％
に、さらに水分１０容量％を添加したもの）を毎分２リ
ットル（標準状態）の流速で流して、反応管内の排ガス
温度を２５０〜５５０℃とし、エタノールと窒素酸化物
とを反応させた。The obtained removing material was filled in a reaction tube, and a gas having a composition shown in Table 1 (a total of 100% by volume of dry components consisting of nitric oxide, carbon dioxide, oxygen, ethanol, and nitrogen).
Was further added with 10% by volume of water) at a flow rate of 2 liters per minute (standard state) to adjust the exhaust gas temperature in the reaction tube to 250 to 550 ° C. to react ethanol and nitrogen oxides.
【００２７】反応管通過後のガス中の窒素酸化物（一酸
化窒素と二酸化窒素の合計量）の濃度を化学発光式窒素
酸化物分析計により測定し、窒素酸化物の除去率を求め
た。結果を表２に示す。The concentration of nitrogen oxides (total amount of nitric oxide and nitrogen dioxide) in the gas after passing through the reaction tube was measured by a chemiluminescence type nitrogen oxide analyzer to determine the removal rate of nitrogen oxides. The results are shown in Table 2.
【００２８】 表１ 成分 濃度（容量割合） 一酸化窒素 500 ppm 二酸化炭素 10 ％ 酸素 10 ％ エタノール 500 ppm 窒素 残部 水分 上記した成分からなるガス量に対して10％Table 1 Component Concentration (Volume Ratio) Nitric Oxide 500 ppm Carbon Dioxide 10% Oxygen 10% Ethanol 500 ppm Nitrogen Residual Moisture 10% with respect to the gas amount of the above components
【００２９】比較例１ 実施例１と同様にして浄化材基材を得た。この浄化材基
材（SO2 に接触させないもの）を用い、他は実施例１と
同様にして反応管通過後のガス中の窒素酸化物（一酸化
窒素と二酸化窒素の合計量）の濃度を化学発光式窒素酸
化物分析計により測定し、窒素酸化物の除去率を求め
た。試験結果を表２に示す。 Comparative Example 1 A purifying material substrate was obtained in the same manner as in Example 1. The concentration of nitrogen oxides (total amount of nitric oxide and nitrogen dioxide) in the gas after passing through the reaction tube was changed in the same manner as in Example 1 except that this purification material base material (which was not brought into contact with SO 2 ) was used. The nitrogen oxide removal rate was determined by measurement with a chemiluminescent nitrogen oxide analyzer. The test results are shown in Table 2.
【００３０】実施例２ 実施例１と同一の窒素酸化物除去材を用い、また、表１
に示すガス成分において、エタノールの代わりにプロピ
レンを混合したものを用い、他は実施例１と同様にして
窒素酸化物の除去試験を行った。ここで、ガス中のプロ
ピレンの量は、水分を除いたガス量の５００ppm とし
た。試験結果を表２に示す。 Example 2 The same nitrogen oxide removing material as in Example 1 was used, and Table 1
A nitrogen oxide removal test was conducted in the same manner as in Example 1 except that propylene was mixed instead of ethanol in the gas component shown in (1). Here, the amount of propylene in the gas was 500 ppm, which is the amount of the gas excluding water. The test results are shown in Table 2.
【００３１】比較例２ 実施例１と同様にして浄化材基材を得た。この浄化材基
材（SO2 に接触させないもの）を用い、他は実施例２と
同様にして窒素酸化物の除去試験を行った。試験結果を
表２に示す。 Comparative Example 2 A purifying material substrate was obtained in the same manner as in Example 1. A nitrogen oxide removal test was performed in the same manner as in Example 2 except that this purification material base material (one that was not brought into contact with SO 2 ) was used. The test results are shown in Table 2.
【００３２】 表２ 窒素酸化物除去率（％） 例No. 250℃ 300℃ 350℃ 400℃ 450℃ 500℃ 550℃ 実施例１(1) 82.9 96.6 96.5 92.0 79.9 62.5 44.2 実施例２(2) − 16.0 29.7 60.7 66.9 64.1 43.2 比較例１(1) 76.0 92.0 92.0 87.0 78.0 63.0 45.0 比較例２(2) − 0 2.3 17.2 57.3 56.7 37.8 表２注（1)：エタノールを添加した。 （2)：プロピレンを添加した。Table 2 Nitrogen oxide removal rate (%) Example No. 250 ° C 300 ° C 350 ° C 400 ° C 450 ° C 500 ° C 550 ° C Example 1 (1) 82.9 96.6 96.5 92.0 79.9 62.5 44.2 Example 2 (2) - 16.0 29.7 60.7 66.9 64.1 43.2 Comparative Example 1 (1) 76.0 92.0 92.0 87.0 78.0 63.0 45.0 Comparative Example 2 (2) -0 2.3 17.2 57.3 56.7 37.8 Table 2 Note (1): Ethanol was added. (2): Propylene was added.
【００３３】表２からわかるように、同様の浄化材基材
を用い、同種の添加物質を用いた場合（実施例１と比較
例１、実施例２と比較例２がそれぞれ対応する）、SO2
に接触して処理した浄化材を用いたものが、SO2 による
処理を施していない浄化材（基材）を用いたものより特
に低温域で高い窒素酸化物除去率を示す。すなわち、実
施例１と比較例１とを比較すると、低温域で実施例１の
ほうが良好な窒素酸化物の除去率を示し、また、実施例
２と比較例２とを比較すると、実施例２のほうが良好な
窒素酸化物の除去率を示す。この場合も、特に低温域で
の窒素酸化物除去率が高い。As can be seen from Table 2, when the same purifying material substrate was used and the same kind of additive material was used (Example 1 corresponds to Comparative Example 1 and Example 2 corresponds to Comparative Example 2, respectively), SO 2
The one using the purification material that has been treated by contacting the substrate shows a higher nitrogen oxide removal rate at a particularly low temperature range than the one using the purification material (base material) that has not been treated with SO 2 . That is, comparing Example 1 with Comparative Example 1, Example 1 shows a better nitrogen oxide removal rate in the low temperature region, and comparing Example 2 with Comparative Example 2, Example 2 shows Shows a better removal rate of nitrogen oxides. Also in this case, the nitrogen oxide removal rate is particularly high in the low temperature range.
【００３４】実施例３ 実施例１と同様の方法で粉末状γ−Al2 Ｏ3 （平均粒径
４０μｍ、比表面積２００ｍ2 ／ｇ）に２重量％の銀
（元素換算値）を担持させた。得られた銀担持γ−Al2
Ｏ3 粉末を、市販のコージェライト製ハニカム成形体
（直径３０mm、長さ３５mm、セル数４００／平方イン
チ）の表面にウォッシュコート法によりコートした。コ
ート量は約３ｇであった。 Example 3 In the same manner as in Example 1, powdery γ-Al 2 O 3 (average particle size 40 μm, specific surface area 200 m 2 / g) was loaded with 2% by weight of silver (elemental conversion value). . The obtained silver-supported γ-Al 2
The surface of a commercially available cordierite honeycomb molded body (diameter 30 mm, length 35 mm, cell number 400 / square inch) was coated with O 3 powder by the washcoat method. The coating amount was about 3 g.
【００３５】得られたハニカム成形体を、実施例１と同
様に乾燥、焼成し、実施例１と同様にSO2 処理し、窒素
酸化物除去材を得た。The obtained honeycomb molded body was dried and fired in the same manner as in Example 1, and treated with SO 2 in the same manner as in Example 1 to obtain a nitrogen oxide removing material.
【００３６】得られた除去材について、実施例１と同様
にして窒素酸化物の除去率を求めた。結果を表３に示
す。 表３ 窒素酸化物除去率（％） 例No. 250℃ 300℃ 350℃ 400℃ 450℃ 500℃ 550℃ 実施例３ 82.0 95.0 96.0 92.3 80.0 63.0 45.0 For the obtained removing material, the removal rate of nitrogen oxide was determined in the same manner as in Example 1. The results are shown in Table 3. Table 3 Nitrogen oxide removal rate (%) Example No. 250 ℃ 300 ℃ 350 ℃ 400 ℃ 450 ℃ 500 ℃ 550 ℃ Example 3 82.0 95.0 96.0 92.3 80.0 63.0 45.0
【００３７】この窒素酸化物除去材も、実施例１の除去
材と同等の窒素酸化物除去率を与えることがわかる。It can be seen that this nitrogen oxide removing material also gives a nitrogen oxide removing rate equivalent to that of the removing material of Example 1.
【００３８】[0038]
【発明の効果】以上詳述したように、本発明による窒素
酸化物除去材を用いれば、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。また、本
発明の方法では、排ガス中に水分が１０％程度含まれて
いた場合でも窒素酸化物の除去を効率良く行うことがで
きる。As described above in detail, by using the nitrogen oxide removing material according to the present invention, nitrogen oxides in exhaust gas containing excess oxygen can be efficiently removed. Further, according to the method of the present invention, nitrogen oxides can be efficiently removed even when the exhaust gas contains about 10% of water.
【００３９】本発明の窒素酸化物除去材、及び除去方法
は、各種燃焼機、自動車等の排ガスに含まれる窒素酸化
物の除去に広く利用することができる。The nitrogen oxide removing material and the removing method of the present invention can be widely used for removing nitrogen oxides contained in exhaust gas from various combustors, automobiles and the like.
───────────────────────────────────────────────────── フロントページの続き (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 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kiyohide Yoshida 4-14-1, Suehiro, Kumagaya-shi, Saitama Stock company Riken Kumagaya Works
Claims (5)
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
素酸化物を除去するための除去材であって、多孔質の無
機酸化物に銀又は銀酸化物を担持した浄化材基材を、SO
2 に接触させて処理したことを特徴とする窒素酸化物除
去材。1. A removal material for removing nitrogen oxides from a combustion exhaust gas containing nitrogen oxides and oxygen in a larger amount than the theoretical reaction amount for coexisting unburned components, wherein silver is used as a porous inorganic oxide. Alternatively, the purification material substrate supporting silver oxide is
A nitrogen oxide removing material characterized by being treated by contacting with 2 .
いて、前記多孔質の無機酸化物がアルミナ又はアルミナ
系複合酸化物であることを特徴とする窒素酸化物除去
材。2. The nitrogen oxide removing material according to claim 1, wherein the porous inorganic oxide is alumina or an alumina-based composite oxide.
材において、前記銀又は銀酸化物の担持量が、前記多孔
質の無機酸化物に対して０．１〜１５重量％（元素換算
値）であることを特徴とする窒素酸化物除去材。3. The nitrogen oxide removing material according to claim 1 or 2, wherein the amount of the silver or silver oxide supported is 0.1 to 15% by weight (elemental) with respect to the porous inorganic oxide. Nitrogen oxide removing material, which is a converted value).
酸化物除去材において、前記浄化材基材１ｇあたり、
０．０２〜１mmolのSO2 に接触させてなることを特徴と
する窒素酸化物除去材。4. The nitrogen oxide removing material according to claim 1, wherein 1 g of the purification material base material,
A nitrogen oxide removing material characterized by being brought into contact with 0.02 to 1 mmol of SO 2 .
酸化物除去材を用いて、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除去する方法であって、炭素数が２
以上の炭化水素の１種以上、又は炭素原子を２個以上、
酸素原子を１個以上有する脂肪族含酸素有機化合物の１
種以上を前記排ガスに添加し、前記炭化水素又は前記脂
肪族含酸素有機化合物を添加した排ガスを前記窒素酸化
物除去材に２００〜６００℃で接触させることにより、
前記窒素酸化物と、前記炭化水素又は前記脂肪族含酸素
有機化合物とを反応させて前記窒素酸化物を除去するこ
とを特徴とする窒素酸化物除去方法。5. A nitrogen oxide is removed from a combustion exhaust gas containing the nitrogen oxide and the oxygen larger than the theoretical reaction amount for coexisting unburned components by using the nitrogen oxide removing material according to any one of claims 1 to 4. It is a method of removing things, and has 2 carbon atoms.
One or more of the above hydrocarbons, or two or more carbon atoms,
1 of an aliphatic oxygen-containing organic compound having one or more oxygen atoms
By adding at least one species to the exhaust gas, and contacting the exhaust gas added with the hydrocarbon or the aliphatic oxygen-containing organic compound to the nitrogen oxide removing material at 200 to 600 ° C.,
A method for removing nitrogen oxide, which comprises removing the nitrogen oxide by reacting the nitrogen oxide with the hydrocarbon or the aliphatic oxygen-containing organic compound.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5021788A JPH067641A (en) | 1992-04-30 | 1993-01-14 | Material for removing nitrogen oxide and method for removing nitrogen oxide |
| US08/428,635 US5534237A (en) | 1991-07-23 | 1995-04-25 | Method of cleaning an exhaust gas and exhaust gas cleaner therefor |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13795992 | 1992-04-30 | ||
| JP4-137959 | 1992-04-30 | ||
| JP5021788A JPH067641A (en) | 1992-04-30 | 1993-01-14 | Material for removing nitrogen oxide and method for removing nitrogen oxide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH067641A true JPH067641A (en) | 1994-01-18 |
Family
ID=26358887
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5021788A Pending JPH067641A (en) | 1991-07-23 | 1993-01-14 | Material for removing nitrogen oxide and method for removing nitrogen oxide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH067641A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5658543A (en) * | 1992-12-28 | 1997-08-19 | Kabushiki Kaisha Riken | Exhaust gas cleaner and method for cleaning same |
-
1993
- 1993-01-14 JP JP5021788A patent/JPH067641A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5658543A (en) * | 1992-12-28 | 1997-08-19 | Kabushiki Kaisha Riken | Exhaust gas cleaner and method for cleaning same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3440290B2 (en) | Exhaust gas purification method | |
| JPS63100919A (en) | Purifying method for exhaust gas and catalyst | |
| JP2631814B2 (en) | Exhaust gas purifying material and exhaust gas purifying method | |
| JPH067641A (en) | Material for removing nitrogen oxide and method for removing nitrogen oxide | |
| JP2516145B2 (en) | Nitrogen oxide removal method | |
| JPH06154607A (en) | Catalyst for removal of nitrogen oxide and method for removing nitrogen oxide | |
| JPH06178937A (en) | Catalyst for removing nitrogen oxides and method of removing the same | |
| JP3371127B2 (en) | Exhaust gas purification method | |
| JPH06198172A (en) | Nitrogen oxide removal catalsyt and removing method | |
| JPH06198131A (en) | Material for removing nitrogen oxide and method for removing nitrogen oxide | |
| JPH07163878A (en) | Nitrogen oxide removing catalyst and method | |
| JPH06154609A (en) | Catalyst for removal of nitrogen oxide and method for removing nitrogen oxide | |
| JPH06142523A (en) | Waste gas purifying material and waste gas purifying method | |
| JP3520311B2 (en) | Nitrogen oxide removal method | |
| JP3530214B2 (en) | Exhaust gas purification material and exhaust gas purification method | |
| JPH07275709A (en) | Material and method for purifying exhaust gas | |
| JPH06262078A (en) | Exhaust gas purification material and method of exhaust gas purification | |
| JPH06198195A (en) | Purifying material for exhaust gas and purifying method thereof | |
| JP3509152B2 (en) | Exhaust gas purification material and exhaust gas purification method | |
| JP3508066B2 (en) | Nitrogen oxide removing material and nitrogen oxide removing method | |
| JPH06238164A (en) | Catalyst and method for removing nitrogen oxides | |
| JPH06198176A (en) | Nitrogen oxide removal catalyst and removing method | |
| JPH08999A (en) | Exhaust gas purifying material and exhaust gas purifying method | |
| JPH06142522A (en) | Catalyst for removing nitrogen oxide and method of removing nitrogen oxide | |
| JPH06327974A (en) | Material for purifying waste gas and purifying method of waste gas |