JPH06262078A - Exhaust gas purification material and method of exhaust gas purification - Google Patents
Exhaust gas purification material and method of exhaust gas purificationInfo
- Publication number
- JPH06262078A JPH06262078A JP5076294A JP7629493A JPH06262078A JP H06262078 A JPH06262078 A JP H06262078A JP 5076294 A JP5076294 A JP 5076294A JP 7629493 A JP7629493 A JP 7629493A JP H06262078 A JPH06262078 A JP H06262078A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- silver
- oxide
- oxygen
- nitrogen
- 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
- 239000000463 material Substances 0.000 title claims abstract description 41
- 238000000746 purification Methods 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 title claims description 20
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims abstract description 196
- 239000007789 gas Substances 0.000 claims abstract description 71
- 229910052709 silver Inorganic materials 0.000 claims abstract description 40
- 239000004332 silver Substances 0.000 claims abstract description 40
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 claims abstract description 40
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 34
- 239000001301 oxygen Substances 0.000 claims abstract description 34
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 33
- 229930195733 hydrocarbon Natural products 0.000 claims abstract description 30
- 150000002430 hydrocarbons Chemical class 0.000 claims abstract description 30
- 229910052809 inorganic oxide Inorganic materials 0.000 claims abstract description 23
- 239000004215 Carbon black (E152) Substances 0.000 claims abstract description 20
- 229910001923 silver oxide Inorganic materials 0.000 claims abstract description 20
- 150000002894 organic compounds Chemical class 0.000 claims abstract description 18
- 239000002245 particle Substances 0.000 claims abstract description 16
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 7
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 12
- 239000002131 composite material Substances 0.000 claims description 4
- 238000011144 upstream manufacturing Methods 0.000 claims description 4
- 239000000919 ceramic Substances 0.000 claims description 2
- 229910052751 metal Inorganic materials 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 abstract description 37
- 238000006243 chemical reaction Methods 0.000 abstract description 13
- 238000002485 combustion reaction Methods 0.000 abstract description 12
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 abstract description 5
- 229910002091 carbon monoxide Inorganic materials 0.000 abstract description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052739 hydrogen Inorganic materials 0.000 abstract description 3
- 239000001257 hydrogen Substances 0.000 abstract description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 15
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 10
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 8
- 229910052757 nitrogen Inorganic materials 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 229910021529 ammonia Inorganic materials 0.000 description 5
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 5
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 5
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 4
- 238000010304 firing Methods 0.000 description 4
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 4
- 229910001961 silver nitrate Inorganic materials 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910052878 cordierite Inorganic materials 0.000 description 2
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- 229910002089 NOx Inorganic materials 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- -1 oxygen organic compound Chemical class 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 239000012629 purifying agent Substances 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
Landscapes
- Treating Waste Gases (AREA)
- 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
ことのできる浄化材及びそれを用いた排ガス浄化方法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a purification material capable of effectively removing nitrogen oxides from a combustion exhaust gas containing nitrogen oxides and excess oxygen, and an exhaust gas 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 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 such as nitric oxide and nitrogen dioxide are contained together with oxygen. Here, "containing excess oxygen" means containing more oxygen than the theoretical oxygen amount necessary to burn unburned components such as carbon monoxide, hydrogen, and hydrocarbons contained in the exhaust gas. To do. Moreover, the nitrogen oxide in the following 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。This nitrogen oxide is considered to be one of the causes of acid rain and is 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、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, so that unreacted ammonia is discharged so that nitrogen oxides in exhaust gas are not discharged. There are problems that the amount of ammonia injection must be controlled while measuring the concentration and that the apparatus is generally large.
【０００６】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 、「触媒」vol.33 No.2 、59ページ、1991年
等) 。又、銀を担持する触媒を用いる方法が提案された
（特開平4-281844）。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, "Catalyst" vol.33 No.2, page 59, 1991 etc.). In addition, a method using a catalyst supporting silver has been proposed (JP-A-4-218844).
【０００７】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は狭い温度範囲でしか得られず、ま
た、水分を含むような排ガスでは高い効率で窒素酸化物
を除去することができない。よって、水分を１０％程度
含有し、運転条件によって排ガス温度が変化する実際の
排ガスでは、窒素酸化物の効果的な除去が困難である。However, these methods can effectively remove nitrogen oxides only in a narrow temperature range, and cannot remove nitrogen oxides with high efficiency in exhaust gas containing water. Therefore, it is difficult to effectively remove nitrogen oxides in an actual exhaust gas that contains about 10% of water and the exhaust gas temperature changes depending on operating conditions.
【０００８】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、
効果的に窒素酸化物を除去することができる排ガス浄化
材、及び浄化方法を提供することである。Therefore, an object of the present invention is to remove nitrogen oxides, carbon monoxide, hydrogen, hydrocarbons, etc., such as combustion exhaust gas from a fixed combustion apparatus and a gasoline engine, a diesel engine, etc. that burn under an excess oxygen condition. From the combustion exhaust gas that contains more than the theoretical reaction amount of oxygen for unburned components,
An exhaust gas purifying material and a purifying method capable of effectively removing nitrogen oxides.
【０００９】[0009]
【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特定量の銀
または銀酸化物を、特定の形状で担持してなる浄化材を
用い、この浄化材に特定の温度及び接触時間で排ガスを
接触させると、水分を１０％程度含有する排ガスの場合
でも、排ガスに含まれる窒素酸化物の量に見合うように
排ガス中に添加された炭化水素又は含酸素有機化合物に
より、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 the present invention is a purification material in which a specific amount of silver or silver oxide is supported in a specific shape on a porous inorganic oxide. When the exhaust gas is contacted with this purification material at a specific temperature and contact time, even if the exhaust gas contains about 10% of water, it is added to the exhaust gas so as to be commensurate with the amount of nitrogen oxides contained in the exhaust gas. It was discovered that nitrogen oxides can be effectively removed by such hydrocarbons or oxygen-containing organic compounds, and the present invention has been completed.
【００１０】すなわち、窒素酸化物を除去する本発明の
排ガス浄化材は、多孔質の無機酸化物１００重量％に銀
または銀酸化物を銀元素に換算して０．２〜１５重量％
担持してなり、前記多孔質無機酸化物上の銀または銀酸
化物が平均で直径２０〜１００ｎｍの粒子であり、外部
から前記排ガス中に添加された炭化水素又は含酸素有機
化合物を還元剤として、２００〜６００℃で、前記排ガ
ス中の窒素酸化物を還元することを特徴とする。That is, the exhaust gas purifying material of the present invention for removing nitrogen oxides has a porous inorganic oxide content of 100% by weight and silver or silver oxide in terms of silver element of 0.2 to 15% by weight.
The particles of silver or silver oxide supported on the porous inorganic oxide have an average diameter of 20 to 100 nm, and the hydrocarbon or oxygen-containing organic compound externally added to the exhaust gas is used as a reducing agent. The nitrogen oxide in the exhaust gas is reduced at 200 to 600 ° C.
【００１１】また、窒素酸化物を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前記排ガス中に炭化水素
又は含酸素有機化合物を添加し、２００〜６００℃で前
記排ガスを前記浄化材に接触させ、前記炭化水素又は含
酸素有機化合物と前記窒素酸化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, in the exhaust gas purifying method of the present invention for removing nitrogen oxides, the exhaust gas purifying material is installed in the middle of the exhaust gas conduit, and hydrocarbons or oxygen-containing organic compounds are contained in the exhaust gas on the upstream side of the purifying material. Is added, the exhaust gas is brought into contact with the purifying material at 200 to 600 ° C., and the hydrocarbon or the oxygen-containing organic compound is reacted with the nitrogen oxide to remove the nitrogen oxide.
【００１２】以下、本発明を詳細に説明する。本発明で
は、以下に示す浄化材を用い、この浄化材に排ガスを接
触させることにより、排ガス中の残留炭化水素及び／又
は浄化材の設置部位より上流側で排ガスに添加された炭
化水素又は含酸素有機化合物を還元剤として排ガス中の
窒素酸化物を還元除去する。The present invention will be described in detail below. In the present invention, the purifying material shown below is used, and by contacting the purifying material with the exhaust gas, the residual hydrocarbons in the exhaust gas and / or the hydrocarbons or the hydrocarbons added to the exhaust gas on the upstream side of the installation site of the purifying material are Nitrogen oxides in exhaust gas are reduced and removed using an oxygen organic compound as a reducing agent.
【００１３】まず、本発明の浄化材は多孔質の無機酸化
物に銀または銀酸化物を担持してなる。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。γ−アルミナ又はアルミナ系複合酸化物を用
いることにより、添加した炭化水素又は含酸素有機化合
物と排ガス中の窒素酸化物との反応が効率良く起こる。First, the purification material of the present invention comprises silver or silver oxide supported on a porous inorganic oxide. As the porous inorganic oxide, porous alumina, titania, zirconia, and their composite oxides can be used, but γ-alumina or alumina-based composite oxide is preferably used. By using γ-alumina or an alumina-based composite oxide, the reaction between the added hydrocarbon or oxygen-containing organic compound and the nitrogen oxide in the exhaust gas occurs efficiently.
【００１４】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、無機酸化物への銀成分（銀活性種）の分
散が悪くなり、良好な窒素酸化物の除去が行えない。好
ましい多孔質無機酸化物の比表面積は３０ｍ2 ／ｇ以上
とする。The specific surface area of the porous inorganic oxide is 10 m 2
/ G or more is preferable. Specific surface area of 10 m 2 / g
If it is less than the above range, the dispersion of the silver component (silver active species) in the inorganic oxide becomes poor, and the nitrogen oxide cannot be removed well. The specific surface area of the porous inorganic oxide is preferably 30 m 2 / g or more.
【００１５】本発明の浄化材はペレット状、粉末状、ハ
ニカム状、フォーム状、板状等の形態で用いることがで
きる。本発明の浄化材の好ましい形態は多孔質無機酸化
物に銀または銀酸化物を担持した触媒を、セラミック製
又は金属製でハニカム状、発泡状等の三次元構造体の表
面にコートするか、上記三次元構造体に無機酸化物をコ
ートしたあと、銀または銀酸化物を担持して調製する。
セラミック材として耐熱性の優れたコージェライト、ム
ライトなどが挙げられる。三次元構造体への無機酸化物
のコートは公知のウォッシュコート法などにより行な
う。本発明の浄化材のもう一つの好ましい形態はペレッ
ト状の多孔質無機酸化物に銀または銀酸化物を担持して
用いる。The purifying material of the present invention can be used in the form of pellets, powder, honeycomb, foam, plate or the like. A preferred form of the purifying material of the present invention is a catalyst in which silver or a silver oxide is supported on a porous inorganic oxide, a honeycomb made of a ceramic or a metal, or the surface of a foamed three-dimensional structure is coated, After the inorganic oxide is coated on the three-dimensional structure, silver or silver oxide is supported to prepare the three-dimensional structure.
Examples of the ceramic material include cordierite and mullite, which have excellent heat resistance. The inorganic oxide is coated on the three-dimensional structure by a known wash coating method or the like. Another preferred form of the purifying material of the present invention is used by supporting silver or silver oxide on a pellet-shaped porous inorganic oxide.
【００１６】上記したγ−アルミナ等の無機酸化物に銀
または銀酸化物を担持する場合の担持量は、無機酸化物
を１００重量％として、その０．２〜１５重量％（銀元
素換算値）とする。銀または銀酸化物が０．２重量％
（銀元素換算値）未満では低温側での窒素酸化物の除去
率が低下する。また、１５重量％（銀元素換算値）を超
す量の銀成分を担持すると炭化水素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
くは、銀成分の担持量を無機酸化物１００重量％に対し
て、５重量％を越えて１５重量％以下（銀元素換算値）
とする。When silver or silver oxide is loaded on the above-mentioned inorganic oxide such as γ-alumina, the loading amount is 0.2 to 15% by weight (converted to silver element), with 100% by weight of the inorganic oxide. ). 0.2% by weight of silver or silver oxide
If it is less than the (converted value of silver element), the removal rate of nitrogen oxides on the low temperature side decreases. Further, when a silver component in an amount exceeding 15% by weight (converted into silver element) is carried, the hydrocarbon itself is easily burned, and the nitrogen oxide removal rate is rather lowered. Preferably, the supported amount of the silver component is more than 5% by weight and 15% by weight or less with respect to 100% by weight of the inorganic oxide (silver element conversion value).
And
【００１７】多孔質無機酸化物に担持された銀又は銀酸
化物は粒状を呈しているが、本発明の浄化材では、銀ま
たは銀酸化物の粒子の直径が平均で２０〜１００ｎｍと
する。一般的には、銀成分の粒子径が小さいほど、反応
特性が高いが、平均粒径が２０ｎｍであると、還元剤で
ある炭化水素や、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、平均粒径が
１００ｎｍ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。好ましい平均粒径は３０〜
８０ｎｍ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。また、粒子状銀成分は金属銀または銀
酸化物の形で存在するが、粒子表面では銀酸化物の形で
存在する。The silver or silver oxide supported on the porous inorganic oxide has a granular shape, but in the purifying material of the present invention, the diameter of the silver or silver oxide particles is 20 to 100 nm on average. Generally, the smaller the particle size of the silver component, the higher the reaction characteristics. However, when the average particle size is 20 nm, only the oxidation reaction of the reducing agent hydrocarbon or the oxygen-containing organic compound proceeds, and the nitrogen oxidation occurs. The removal rate of the object is reduced. On the other hand, when the average particle size exceeds 100 nm, the reaction characteristics of the silver component are reduced and the nitrogen oxide removal rate is reduced. A preferred average particle size is 30-
80 nm. In addition, the average here means an arithmetic mean. Further, the particulate silver component exists in the form of metallic silver or silver oxide, but exists in the form of silver oxide on the surface of the particles.
【００１８】γ−アルミナ等の無機酸化物に銀成分を担
持する方法としては、公知の含浸法や、混練法等を用い
ることができる。担持後の浄化材の調整は、５０〜１５
０℃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、空気中又は窒素流通
下、あるいは水素ガス流通下、もしくは真空排気しなが
ら行うのが好ましい。酸化雰囲気下、６００℃で一時間
以上焼成することにより、担持された銀成分の粒子径を
所望の大きさにすることができる。この時、窒素酸化物
が存在すれば、より効果的に焼成できる。なお、窒素ガ
スまたは水素ガス流通下で焼成した浄化材は、最後に酸
化処理を行うことが好ましい。As a method for supporting the silver component on the inorganic oxide such as γ-alumina, known impregnation method, kneading method and the like can be used. Adjustment of the purifying material after loading is 50 to 15
After drying at about 0 ° C., it is preferable to raise the temperature stepwise at 100 to 600 ° C. and bake. The firing is preferably performed in air or under nitrogen flow, or under hydrogen gas flow, or while evacuating. By calcining at 600 ° C. for one hour or more in an oxidizing atmosphere, the particle size of the supported silver component can be set to a desired size. At this time, if nitrogen oxide is present, the firing can be performed more effectively. In addition, it is preferable that the purification material fired under the flow of nitrogen gas or hydrogen gas is finally oxidized.
【００１９】次に、本発明の方法について説明する。ま
ず、上述した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, the above-mentioned purification material is installed in the middle of the exhaust gas conduit.
【００２０】排ガス中には、残留炭化水素としてアセチ
レン、メタン、エタン、プロピレン等が含まれるが、排
ガス中のNOx を還元するのに十分な量の残留炭化水素が
含まれていない場合には、外部から炭化水素又は含酸素
有機化合物を排ガス中に導入する。炭化水素又は含酸素
有機化合物の導入位置は、浄化材を設置した位置より上
流側である。The exhaust gas contains acetylene, methane, ethane, propylene and the like as residual hydrocarbons, but when the residual hydrocarbons are not contained in an amount sufficient to reduce NOx in the exhaust gas, A hydrocarbon or an oxygen-containing organic compound is introduced into the exhaust gas from the outside. The introduction position of the hydrocarbon or the oxygen-containing organic compound is upstream of the position where the purification material is installed.
【００２１】外部から導入する炭化水素としては、プロ
ピレン、アセチレン、プロパン等の標準状態でガス状の
炭化水素の他に、標準状態で液体状の炭化水素も用いる
ことができる。標準状態で液体状の炭化水素としては、
具体的には、軽油、セタン、ヘプタン、灯油等が挙げら
れる。含酸素有機化合物として、エタノール等のアルコ
ール類が好ましい。これらの添加物は、噴霧等の方法で
排ガス中に導入することができる。As the hydrocarbon introduced from the outside, in addition to the gaseous hydrocarbon in the standard state such as propylene, acetylene, propane, etc., a hydrocarbon in the liquid state in the standard state can be used. As a liquid hydrocarbon in the standard state,
Specific examples include light oil, cetane, heptane, and kerosene. As the oxygen-containing organic compound, alcohols such as ethanol are preferable. These additives can be introduced into the exhaust gas by a method such as spraying.
【００２２】外部から導入する炭化水素又は含酸素有機
化合物の量は、排ガス中の窒素酸化物の重量の５倍以下
とするのが好ましい。添加量が５倍を超えると、燃費の
悪化を招く。より好ましくは０．２〜４倍とする。The amount of hydrocarbon or oxygen-containing organic compound introduced from the outside is preferably not more than 5 times the weight of nitrogen oxide in the exhaust gas. If the addition amount exceeds 5 times, the fuel efficiency is deteriorated. It is more preferably 0.2 to 4 times.
【００２３】本発明では、炭化水素または含酸素有機化
合物を含む排ガスが上記した浄化材と接触する時間を調
節し、添加物と窒素酸化物との反応を効率良く進行させ
る。実用的な立場で考えて、炭化水素又は含酸素有機化
合物を含む排ガスと浄化材との接触時間は０．００６ｇ
・秒／ml以上とする。好ましい接触時間は０．００７ｇ
・秒／ml以上とする。In the present invention, the time during which the exhaust gas containing a hydrocarbon or an oxygen-containing organic compound is in contact with the above-mentioned purification material is adjusted so that the reaction between the additive and the nitrogen oxides proceeds efficiently. From a practical standpoint, the contact time between the exhaust gas containing hydrocarbon or oxygen-containing organic compound and the purification material is 0.006g.
・ Seconds / ml or more. Preferred contact time is 0.007g
・ Seconds / ml or more.
【００２４】また、本発明では、炭化水素又は含酸素有
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２００〜６００℃に保
つ。排ガスの温度が２００℃未満であると窒素酸化物の
還元反応が進行せず、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３０
０〜５５０℃である。Further, in the present invention, the temperature of the exhaust gas at the purification material installation site where the hydrocarbon or oxygen-containing organic compound reacts with the nitrogen oxide is maintained at 200 to 600 ° C. If the temperature of the exhaust gas is less than 200 ° C., the reduction reaction of nitrogen oxides does not proceed, and good removal of nitrogen oxides cannot be performed. On the other hand, if the temperature exceeds 600 ° C., the combustion of the hydrocarbon or the oxygen-containing organic compound itself starts, and the nitrogen oxide cannot be reduced and removed. Preferred exhaust gas temperature is 30
It is 0-550 degreeC.
【００２５】[0025]
【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γ−アルミナ（直径1.5mm 、長さ約６
mm、比表面積２００ｍ2 ／ｇ）５ｇに硝酸銀水溶液を用
いて、銀成分を５重量％担持した。次に、８０℃で２時
間乾燥後、空気中段階的に６００℃まで昇温したあと、
５時間焼成し、銀又は銀酸化物の平均粒径が５０ｎｍで
ある浄化材を調製した。なお、粒子径は電子顕微鏡を用
いて計測した。The present invention will be described in more detail by the following specific examples. Example 1 Commercially available pelletized γ-alumina (diameter 1.5 mm, length about 6
mm, specific surface area 200 m 2 / g) 5 g of an aqueous silver nitrate solution was used to carry 5% by weight of a silver component. Next, after drying at 80 ° C. for 2 hours, the temperature was gradually raised to 600 ° C. in air,
Firing was performed for 5 hours to prepare a purifying material having an average particle diameter of silver or silver oxide of 50 nm. The particle size was measured using an electron microscope.
【００２６】この浄化材３．７５ｇを反応管内に設置
し、表１に示す組成のガス（一酸化窒素、二酸化炭素、
酸素、プロピレン、及び窒素からなる乾燥成分の合計１
００容量％に、さらに水分１０容量％を添加したもの）
を毎分４．４リットル（標準状態）の流量で流して（接
触時間０．０５ｇ・秒／ml、空間速度３００００ｈ
ｒ-1）、反応管内の排ガス温度を２５０〜５５０℃の範
囲の保ち、プロピレンと窒素酸化物とを反応させた。3.75 g of this purification material was placed in a reaction tube, and a gas having the composition shown in Table 1 (nitrogen monoxide, carbon dioxide,
A total of 1 dry ingredients consisting of oxygen, propylene, and nitrogen
(00% by volume added with 10% by volume of water)
At a flow rate of 4.4 liters per minute (standard condition) (contact time 0.05 g · sec / ml, space velocity 30,000 h
r −1 ), the exhaust gas temperature in the reaction tube was maintained in the range of 250 to 550 ° C., and propylene and nitrogen oxide were reacted.
【００２７】反応管通過後のガスの窒素酸化物（一酸化
窒素、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。結果を図１に示す。The concentration of nitrogen oxides (total amount of nitric oxide and nitrogen dioxide) of 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 Fig. 1.
【００２８】 表１ 成分 濃度 一酸化窒素 800 ppm 一酸化炭素 100 ppm 酸素 10 容量％ プロピレン 1714 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容量％Table 1 Concentration of components Nitric oxide 800 ppm Carbon monoxide 100 ppm Oxygen 10% by volume Propylene 1714 ppm Nitrogen balance Moisture 10% by volume with respect to the amount of gas composed of the above components
【００２９】実施例２ 硝酸銀水溶液を用いて銀成分を３重量％担持した粉末状
γ−アルミナ（比表面積２００ｍ2 ／ｇ）１．５ｇを、
市販のコージェライト製ハニカム状成形体（直径３０m
m、長さ約１２．６mm）にコートーし、８０℃で２時間
乾燥後、空気中段階的に６００℃まで昇温したあと、５
時間焼成し、銀又は銀酸化物の平均粒径が４５ｎｍであ
る浄化材を調製した。 Example 2 1.5 g of powdery γ-alumina (specific surface area 200 m 2 / g) carrying 3% by weight of silver component using an aqueous solution of silver nitrate,
Commercially available cordierite honeycomb shaped body (diameter 30 m
m, length about 12.6 mm), dried at 80 ° C for 2 hours, and then stepwise heated to 600 ° C in air, then 5
Firing was performed for a period of time to prepare a purifying material having an average particle diameter of silver or silver oxide of 45 nm.
【００３０】この浄化材を反応管内に設置し、表２に示
す組成のガス（一酸化窒素、二酸化炭素、酸素、軽油、
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）を用い、実施例１と
同様な条件で窒素酸化物の除去実験を行った。This purifying material was placed in a reaction tube, and a gas having the composition shown in Table 2 (nitrogen monoxide, carbon dioxide, oxygen, light oil,
A nitrogen oxide removal experiment was performed under the same conditions as in Example 1 using 100% by volume of the total dry components consisting of nitrogen and nitrogen, to which 10% by volume of water was further added.
【００３１】反応管通過後のガスの窒素酸化物（一酸化
窒素、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。結果を図１に示す。The concentration of nitrogen oxides (total amount of nitric oxide and nitrogen dioxide) of 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 Fig. 1.
【００３２】 表２ 成分 濃度 一酸化窒素 800 ppm 一酸化炭素 100 ppm 酸素 10 容量％ 軽油 窒素酸化物の質量の３倍 窒素 残部 水分 上記した成分からなるガス量に対して10容量％Table 2 Concentration of components Nitrogen monoxide 800 ppm Carbon monoxide 100 ppm Oxygen 10% by volume Light oil 3 times the mass of nitrogen oxides Nitrogen balance Water content 10% by volume with respect to the amount of gas composed of the above components
【００３３】比較例１ 実施例１で用いたγ−アルミナペレットと同一のものに
硝酸銀水溶液を用いて硝酸銀を５重量％（銀元素換算）
担持して、実施例１と同様の方法で３００℃まで焼成
し、銀または銀酸化物の平均粒径が１５ｎｍの浄化剤を
調製した。実施例１と同様な条件で窒素酸化物の除去試
験を行った。結果を図１に示す。COMPARATIVE EXAMPLE 1 Silver nitrate solution was added to the same γ-alumina pellets used in Example 1 to prepare silver nitrate of 5 wt% (converted to silver element).
It was carried and calcined to 300 ° C. in the same manner as in Example 1 to prepare a purifying agent having an average particle diameter of silver or silver oxide of 15 nm. A nitrogen oxide removal test was conducted under the same conditions as in Example 1. The results are shown in Fig. 1.
【００３４】図１からわかるように、銀成分の平均粒径
が５０ｎｍ前後の実施例１、２では、広い温度範囲にわ
たって窒素酸化物の良好な除去がみられた。一方、平均
粒径が２０ｎｍ以下の比較例１では、全温度範囲にわた
って窒素酸化物除去率の低下がみられた。As can be seen from FIG. 1, in Examples 1 and 2 in which the average particle diameter of the silver component was around 50 nm, good removal of nitrogen oxides was observed over a wide temperature range. On the other hand, in Comparative Example 1 having an average particle size of 20 nm or less, the nitrogen oxide removal rate was decreased over the entire temperature range.
【００３５】[0035]
【発明の効果】以上詳述したように、本発明によれば、
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％程度含まれている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 in detail above, according to the present invention,
The nitrogen oxides in the 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.
【００３６】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 exhaust gas purifying material and the purifying method of the present invention can be widely used for removing nitrogen oxides contained in exhaust gas of various combustors, automobiles and the like.
【図１】実施例１、２及び比較例１における窒素酸化物
の除去率と排ガス温度との関係を示すグラフである。FIG. 1 is a graph showing a relationship between a nitrogen oxide removal rate and an exhaust gas temperature in Examples 1 and 2 and Comparative Example 1.
───────────────────────────────────────────────────── 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 (72)発明者 宮寺 達雄 茨城県つくば市小野川16番３ 工業技術院 資源環境技術総合研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyohide Yoshida 4-14-1, Suehiro, Kumagaya-shi, Saitama Stock company Riken Kumagaya Plant (72) Inventor Tatsuo Miyadera 16-3 Onogawa, Tsukuba, Ibaraki Industrial Technology Institute for Natural Resources and Environment Technology
Claims (4)
は銀酸化物を銀元素に換算して０．２〜１５重量％担持
してなる窒素酸化物を除去する浄化材において、前記多
孔質無機酸化物上の銀または銀酸化物が平均で直径２０
〜１００ｎｍの粒子であり、外部から前記排ガス中に添
加された炭化水素又は含酸素有機化合物を還元剤とし
て、２００〜６００℃で、前記排ガス中の窒素酸化物を
還元することを特徴とする排ガス浄化材。1. A purifying material for removing nitrogen oxides, which comprises 0.2 to 15% by weight of silver or silver oxide converted to elemental silver on 100% by weight of a porous inorganic oxide, wherein Of silver or silver oxide on porous inorganic oxide has an average diameter of 20
~ 100 nm particles, the exhaust gas characterized by reducing the nitrogen oxides in the exhaust gas at 200 ~ 600 ℃, using a hydrocarbon or oxygen-containing organic compound externally added to the exhaust gas as a reducing agent Purifying material.
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排ガス浄化材。2. The exhaust gas purifying material according to claim 1, wherein the porous inorganic oxide is alumina or an alumina-based composite oxide.
おいて、前記浄化材はさらにセラミック製又は金属製三
次元構造体を含有し、前記多孔質無機酸化物が前記三次
元構造体にコートされていることを特徴とする排ガス浄
化材。3. The exhaust gas purification material according to claim 1 or 2, wherein the purification material further contains a ceramic or metal three-dimensional structure, and the porous inorganic oxide coats the three-dimensional structure. Exhaust gas purification material characterized by being
求項１〜３のいずれかに記載の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前記排ガス中
に炭化水素又は含酸素有機化合物を添加し、２００〜６
００℃で前記排ガスを前記浄化材に接触させ、前記炭化
水素又は含酸素有機化合物と前記窒素酸化物とを反応さ
せて前記窒素酸化物を除去することを特徴とする排ガス
浄化方法。4. A method for removing nitrogen oxides, wherein the exhaust gas purifying material according to any one of claims 1 to 3 is installed in the middle of an exhaust gas conduit, and hydrocarbons are contained in the exhaust gas upstream of the purifying material. Alternatively, an oxygen-containing organic compound is added to add 200 to 6
An exhaust gas purification method comprising contacting the exhaust gas with the purification material at 00 ° C. to react the hydrocarbon or the oxygen-containing organic compound with the nitrogen oxide to remove the nitrogen oxide.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5076294A JPH06262078A (en) | 1993-03-10 | 1993-03-10 | Exhaust gas purification material and method of exhaust gas purification |
| EP19930310560 EP0605237B1 (en) | 1992-12-28 | 1993-12-24 | Exhaust gas cleaner |
| DE1993609245 DE69309245T2 (en) | 1992-12-28 | 1993-12-24 | Exhaust gas cleaner |
| US08/434,918 US5714432A (en) | 1992-12-28 | 1995-05-04 | Exhaust gas cleaner comprising supported silver or silver oxide particles |
| US08/601,495 US5656249A (en) | 1992-12-28 | 1996-02-14 | Exhaust gas cleaner and method for removing nitrogen oxides |
| US08/805,234 US5772973A (en) | 1992-12-28 | 1997-02-24 | Exhaust gas cleaner and method for removing nitrogen oxides |
| US08/917,144 US5801117A (en) | 1992-12-28 | 1997-08-25 | Comprising supported silver sulfate or silver chloride or silver with sulfuric acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5076294A JPH06262078A (en) | 1993-03-10 | 1993-03-10 | Exhaust gas purification material and method of exhaust gas purification |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06262078A true JPH06262078A (en) | 1994-09-20 |
Family
ID=13601334
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5076294A Pending JPH06262078A (en) | 1992-12-28 | 1993-03-10 | Exhaust gas purification material and method of exhaust gas purification |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06262078A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5780002A (en) * | 1994-11-04 | 1998-07-14 | Jiro Hiraishi, Director-General Of Agency Of Industrial Science And Technology | Exhaust gas cleaner and method for cleaning exhaust gas |
| JP2010504206A (en) * | 2006-09-20 | 2010-02-12 | ビーエーエスエフ、カタリスツ、エルエルシー | Catalyst and production method for reducing NOx in exhaust gas stream |
| JP2010284648A (en) * | 2002-11-27 | 2010-12-24 | Volvo Technology Corp | Catalyst unit for reduction of nox compound |
-
1993
- 1993-03-10 JP JP5076294A patent/JPH06262078A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5780002A (en) * | 1994-11-04 | 1998-07-14 | Jiro Hiraishi, Director-General Of Agency Of Industrial Science And Technology | Exhaust gas cleaner and method for cleaning exhaust gas |
| US5882607A (en) * | 1994-11-04 | 1999-03-16 | Agency Of Industrial Science And Technology | Exhaust gas cleaner and method for cleaning exhaust gas |
| JP2010284648A (en) * | 2002-11-27 | 2010-12-24 | Volvo Technology Corp | Catalyst unit for reduction of nox compound |
| JP2010504206A (en) * | 2006-09-20 | 2010-02-12 | ビーエーエスエフ、カタリスツ、エルエルシー | Catalyst and production method for reducing NOx in exhaust gas stream |
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