JPH0780306A - Waste gas purifying material and waste gas purifying method - Google Patents
Waste gas purifying material and waste gas purifying methodInfo
- Publication number
- JPH0780306A JPH0780306A JP6186606A JP18660694A JPH0780306A JP H0780306 A JPH0780306 A JP H0780306A JP 6186606 A JP6186606 A JP 6186606A JP 18660694 A JP18660694 A JP 18660694A JP H0780306 A JPH0780306 A JP H0780306A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- catalyst
- silver
- nitrogen oxides
- 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
- 239000000463 material Substances 0.000 title claims abstract description 118
- 238000000034 method Methods 0.000 title claims description 37
- 239000002912 waste gas Substances 0.000 title abstract 8
- 239000003054 catalyst Substances 0.000 claims abstract description 159
- 229910052709 silver Inorganic materials 0.000 claims abstract description 68
- 239000004332 silver Substances 0.000 claims abstract description 68
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims abstract description 67
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 47
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 47
- 239000001301 oxygen Substances 0.000 claims abstract description 47
- 238000006243 chemical reaction Methods 0.000 claims abstract description 45
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims abstract description 37
- 239000010931 gold Substances 0.000 claims abstract description 37
- 229910052737 gold Inorganic materials 0.000 claims abstract description 37
- 239000000203 mixture Substances 0.000 claims abstract description 37
- 229930195733 hydrocarbon Natural products 0.000 claims abstract description 22
- 150000002430 hydrocarbons Chemical class 0.000 claims abstract description 22
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 20
- 239000004215 Carbon black (E152) Substances 0.000 claims abstract description 14
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims description 310
- 239000007789 gas Substances 0.000 claims description 149
- 238000000746 purification Methods 0.000 claims description 78
- 229910052809 inorganic oxide Inorganic materials 0.000 claims description 50
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 37
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 34
- 150000002894 organic compounds Chemical class 0.000 claims description 23
- 238000002485 combustion reaction Methods 0.000 claims description 18
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 15
- 239000002131 composite material Substances 0.000 claims description 12
- 229910052697 platinum Inorganic materials 0.000 claims description 11
- 230000001603 reducing effect Effects 0.000 claims description 10
- 229940100890 silver compound Drugs 0.000 claims description 10
- 150000003379 silver compounds Chemical class 0.000 claims description 10
- 229910052703 rhodium Inorganic materials 0.000 claims description 8
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 6
- 229910052763 palladium Inorganic materials 0.000 claims description 6
- 239000008188 pellet Substances 0.000 claims description 6
- 239000011248 coating agent Substances 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 5
- 229910052741 iridium Inorganic materials 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 229910052707 ruthenium Inorganic materials 0.000 claims description 5
- 239000000395 magnesium oxide Substances 0.000 claims description 3
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 3
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 3
- 238000011144 upstream manufacturing Methods 0.000 claims description 3
- 239000011787 zinc oxide Substances 0.000 claims description 3
- 239000000919 ceramic Substances 0.000 claims description 2
- 239000008187 granular material Substances 0.000 claims 1
- 239000000567 combustion gas Substances 0.000 abstract 1
- 238000000151 deposition Methods 0.000 abstract 1
- 239000002699 waste material Substances 0.000 abstract 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 23
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 23
- 239000000758 substrate Substances 0.000 description 21
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 18
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 18
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 18
- 239000007864 aqueous solution Substances 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 12
- 239000002253 acid Substances 0.000 description 11
- 229910052757 nitrogen Inorganic materials 0.000 description 11
- 239000002245 particle Substances 0.000 description 11
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 10
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 10
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 9
- 229910002091 carbon monoxide Inorganic materials 0.000 description 9
- 238000011156 evaluation Methods 0.000 description 9
- 229910001961 silver nitrate Inorganic materials 0.000 description 9
- 239000000243 solution Substances 0.000 description 9
- 229910021607 Silver chloride Inorganic materials 0.000 description 8
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 8
- 238000010304 firing Methods 0.000 description 7
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- 238000005470 impregnation Methods 0.000 description 6
- 229910021529 ammonia Inorganic materials 0.000 description 5
- 229910052878 cordierite Inorganic materials 0.000 description 5
- 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 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 235000019270 ammonium chloride Nutrition 0.000 description 3
- 238000001354 calcination Methods 0.000 description 3
- 238000010531 catalytic reduction reaction Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- -1 etc.) Inorganic materials 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 150000002431 hydrogen Chemical class 0.000 description 3
- 238000011068 loading method Methods 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 229910052761 rare earth metal Inorganic materials 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 238000003980 solgel method Methods 0.000 description 3
- 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 2
- 229910052684 Cerium Inorganic materials 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 2
- 229910002089 NOx Inorganic materials 0.000 description 2
- 239000011865 Pt-based catalyst Substances 0.000 description 2
- 150000001335 aliphatic alkanes Chemical class 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 229910001923 silver oxide Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 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
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 241000416536 Euproctis pseudoconspersa Species 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 150000001345 alkine derivatives Chemical class 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001816 cooling Methods 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
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000003779 heat-resistant material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 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
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- FJOLTQXXWSRAIX-UHFFFAOYSA-K silver phosphate Chemical compound [Ag+].[Ag+].[Ag+].[O-]P([O-])([O-])=O FJOLTQXXWSRAIX-UHFFFAOYSA-K 0.000 description 1
- 229940019931 silver phosphate Drugs 0.000 description 1
- 229910000161 silver phosphate Inorganic materials 0.000 description 1
- YPNVIBVEFVRZPJ-UHFFFAOYSA-L silver sulfate Chemical compound [Ag+].[Ag+].[O-]S([O-])(=O)=O YPNVIBVEFVRZPJ-UHFFFAOYSA-L 0.000 description 1
- 229910000367 silver sulfate Inorganic materials 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
- 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
ことのできる排ガス浄化材及びそれを用いた浄化方法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purification material capable of effectively removing nitrogen oxides from a combustion exhaust gas containing nitrogen oxides and excess oxygen, and a purification method using the same.
【０００２】[0002]
【従来の技術及び発明が解決しようとする課題】自動車
用エンジン等の内燃機関や、工場等に設置された燃焼機
器、家庭用ファンヒーターなどから排出される各種の燃
焼排ガス中には、過剰の酸素とともに一酸化窒素、二酸
化窒素等の窒素酸化物が含まれている。ここで、「過剰
の酸素を含む」とは、その排ガス中に含まれる一酸化炭
素、水素、炭化水素等の未燃焼成分を燃焼するのに必要
な理論酸素量より多い酸素を含むことを意味する。ま
た、以下における窒素酸化物とは一酸化窒素及び／又は
二酸化窒素を指す。2. Description of the Related Art Excessive 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】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 、「触媒」vol.33 No.2 、59ページ、1991年
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, "Catalyst" vol.33 No.2, page 59, 1991 etc.).
【０００８】しかしながら、これらの方法では、窒素酸
化物の除去温度領域が狭く、また、水分を含み、運転条
件によって温度変化の大きい排ガスでは、窒素酸化物の
除去率が著しく低下することがわかった。However, it has been found that these methods have a narrow temperature range for removing nitrogen oxides, and that the exhaust gas containing water and having a large temperature change depending on operating conditions has a significantly low nitrogen oxide removal rate. .
【０００９】したがって、本発明の目的は、固定燃焼装
置および酸素過剰条件で燃焼するガソリンエンジン、デ
ィーゼルエンジン等からの燃焼排ガスのように、窒素酸
化物や、一酸化炭素、水素、炭化水素等の未燃焼分に対
する理論反応量以上の酸素を含有する燃焼排ガスから、
効率良く窒素酸化物を除去することができる排ガス浄化
材及び排ガス浄化方法を提供することである。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 device 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 an exhaust gas purifying method capable of efficiently removing nitrogen oxides.
【００１０】[0010]
【課題を解決するための手段】上記課題に鑑み鋭意研究
の結果、本発明者は、多孔質の無機酸化物に銀成分と金
成分をそれぞれ特定量担持してなる排ガス浄化材、ある
いは多孔質の無機酸化物に銀成分と金成分及びPt等の成
分をそれぞれ担持してなる排ガス浄化材を用い、排ガス
中に有機化合物を添加して特定の温度で上記の触媒に排
ガスを接触させれば、１０％の水分を含む排ガスでも、
広い温度領域で窒素酸化物を効果的に除去することがで
きることを発見し、本発明を完成した。As a result of earnest research in view of the above problems, the present inventor has found that an exhaust gas purifying material or a porous inorganic oxide in which a specific amount of a silver component and a gold component are supported, respectively. Using an exhaust gas purifying material in which a silver component, a gold component, and a component such as Pt are respectively supported on the inorganic oxide, the organic compound is added to the exhaust gas, and the exhaust gas is brought into contact with the catalyst at a specific temperature. Exhaust gas containing 10% moisture,
The present invention has been completed by discovering that nitrogen oxides can be effectively removed in a wide temperature range.
【００１１】すなわち、本発明の第一の排ガス浄化材
は、排ガス流入側に第一の触媒を有し、排ガス流出側に
第二の触媒を有して、前記第一の触媒が多孔質の無機酸
化物に活性種である銀及び／又は銀化合物、又はそれら
の混合物０．２〜１５重量％（銀元素換算値）を担持し
てなり、前記第二の触媒が多孔質の無機酸化物に活性種
である金０．０２〜５重量％を担持してなり、外部から
前記排ガス中に炭化水素及び／又は含酸素有機化合物を
還元剤として添加し、１５０〜６５０℃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 first exhaust gas purifying material of the present invention has the first catalyst on the exhaust gas inflow side and the second catalyst on the exhaust gas outflow side, and the first catalyst is porous. The inorganic oxide carries silver and / or a silver compound, which is an active species, or a mixture thereof in an amount of 0.2 to 15% by weight (converted to a silver element), and the second catalyst is a porous inorganic oxide. 0.02 to 5% by weight of gold, which is an active species, is supported on the exhaust gas, and a hydrocarbon and / or an oxygen-containing organic compound is added to the exhaust gas from the outside as a reducing agent. It is characterized by reducing the nitrogen oxides.
【００１２】また、本発明の第二の排ガス浄化材は、第
一の触媒と第二の触媒を混合して用い、前記第一の触媒
が多孔質の無機酸化物に活性種である銀及び／又は銀化
合物、又はそれらの混合物０．２〜１５重量％（銀元素
換算値）を担持してなり、前記第二の触媒が多孔質の無
機酸化物に活性種である金０．０２〜５重量％を担持し
てなり、外部から前記排ガス中に炭化水素及び／又は含
酸素有機化合物を還元剤として添加し、１５０〜６５０
℃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。The second exhaust gas purifying material of the present invention is a mixture of the first catalyst and the second catalyst, wherein the first catalyst is a porous inorganic oxide containing silver as an active species and silver. And / or a silver compound, or a mixture thereof in an amount of 0.2 to 15% by weight (converted to a silver element), and the second catalyst is a porous inorganic oxide containing 0.02% of gold which is an active species. 5% by weight is supported, and a hydrocarbon and / or an oxygen-containing organic compound is added to the exhaust gas as a reducing agent from the outside to obtain 150 to 650.
It is characterized in that the nitrogen oxides in the exhaust gas are reduced at 0 ° C.
【００１３】そして、本発明の第三の排ガス浄化材は、
排ガス流入側から流出側に順に第一、第二、第三の触媒
を有して、前記第一の触媒が多孔質の無機酸化物に活性
種である銀及び／又は銀化合物、又はそれらの混合物
０．２〜１５重量％（銀元素換算値）を担持してなり、
前記第二の触媒が多孔質の無機酸化物に活性種である金
０．０２〜５重量％を担持してなり、前記第三の触媒が
多孔質の無機酸化物に活性種であるPt、Pd、Ru、Rh、Ir
からなる群より選ばれた少なくとも１種の元素０．０２
〜５重量％を担持してなり、外部から前記排ガス中に炭
化水素及び／又は含酸素有機化合物を還元剤として添加
し、１５０〜６５０℃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。The third exhaust gas purifying material of the present invention is
From the exhaust gas inflow side to the outflow side, the first, second, and third catalysts are sequentially provided, and the first catalyst is silver and / or a silver compound which is an active species in a porous inorganic oxide, or a combination thereof. The mixture is loaded with 0.2 to 15% by weight (converted to silver element),
The second catalyst comprises 0.02 to 5% by weight of gold which is an active species in a porous inorganic oxide, and the third catalyst is Pt which is an active species in a porous inorganic oxide, Pd, Ru, Rh, Ir
0.02 of at least one element selected from the group consisting of
˜5 wt% is supported, and a hydrocarbon and / or an oxygen-containing organic compound is externally added to the exhaust gas as a reducing agent to reduce nitrogen oxides in the exhaust gas at 150 to 650 ° C. Characterize.
【００１４】さらに、本発明の第四の排ガス浄化材は、
第一の触媒、第二の触媒及び第三の触媒を混合して用
い、前記第一の触媒が多孔質の無機酸化物に活性種であ
る銀及び／又は銀化合物、又はそれらの混合物０．２〜
１５重量％（銀元素換算値）を担持してなり、前記第二
の触媒が多孔質の無機酸化物に活性種である金０．０２
〜５重量％を担持してなり、前記第三の触媒が多孔質の
無機酸化物に活性種であるPt、Pd、Ru、Rh、Irからなる
群より選ばれた少なくとも１種の元素０．０２〜５重量
％を担持してなり、外部から前記排ガス中に炭化水素及
び／又は含酸素有機化合物を還元剤として添加し、１５
０〜６５０℃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。Further, the fourth exhaust gas purifying material of the present invention is
A mixture of a first catalyst, a second catalyst and a third catalyst, wherein the first catalyst is silver and / or a silver compound in which a porous inorganic oxide is an active species, or a mixture thereof. 2 to
15% by weight (silver element conversion value) is supported, and the second catalyst is 0.02 gold which is an active species in the porous inorganic oxide.
.About.5% by weight, and the third catalyst contains at least one element selected from the group consisting of Pt, Pd, Ru, Rh, and Ir, which is an active species, in a porous inorganic oxide. 02 to 5 wt% is supported, and a hydrocarbon and / or an oxygen-containing organic compound is added to the exhaust gas as a reducing agent from the outside.
It is characterized by reducing nitrogen oxides in the exhaust gas at 0 to 650 ° C.
【００１５】さらにまた、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排ガス浄化方法は、前記
排ガス浄化材を排ガス導管の途中に設置し、前記浄化材
の上流側で炭化水素及び／又は含酸素有機化合物を添加
した排ガスを、１５０〜６００℃において前記浄化材に
接触させ、もって前記排ガス中の有機化合物との反応に
より前記窒素酸化物を除去することを特徴とする。Furthermore, in an exhaust gas purification method for removing nitrogen oxides from a combustion exhaust gas containing nitrogen oxides and oxygen in an amount larger than the theoretical reaction amount for coexisting unburned components, the exhaust gas purification material is provided in the middle of the exhaust gas conduit. The exhaust gas, which is installed and added with a hydrocarbon and / or an oxygen-containing organic compound on the upstream side of the purification material, is brought into contact with the purification material at 150 to 600 ° C., and thus the nitrogen is produced by a reaction with the organic compound in the exhaust gas. It is characterized by removing oxides.
【００１６】以下、本発明を詳細に説明する。本発明の
排ガス浄化材は下記二つの形態をとることが可能であ
る。第一の好ましい形態は、後述の粉末状多孔質無機酸
化物に触媒活性種を担持してなる触媒を浄化材基体にコ
ートしてなる浄化材である。浄化材の基体を形成するセ
ラミックス材料としては、γ−アルミナ及びその複合酸
化物（γ−アルミナ−チタニア、γ−アルミナ−シリ
カ、γ−アルミナ−ジルコニア等）、ジルコニア、チタ
ニア−ジルコニアなどの多孔質で表面積の大きい耐熱性
のものが挙げられる。高耐熱性が要求される場合、コー
ジェライト、ムライト、アルミナ及びその複合物等を用
いるのが好ましい。また、排ガス浄化材の基体に公知の
金属材料を用いることもできる。The present invention will be described in detail below. The exhaust gas purifying material of the present invention can take the following two forms. The first preferred form is a purifying material obtained by coating a purifying material base with a catalyst, which will be described later, carrying a catalytically active species on a powdery porous inorganic oxide. As the ceramic material forming the substrate of the purification material, γ-alumina and its composite oxides (γ-alumina-titania, γ-alumina-silica, γ-alumina-zirconia, etc.), zirconia, titania-zirconia, etc. are porous. A heat-resistant material having a large surface area can be used. When high heat resistance is required, it is preferable to use cordierite, mullite, alumina and their composites. Also, a known metal material can be used for the substrate of the exhaust gas purifying material.
【００１７】排ガス浄化材の基体の形状及び大きさは、
目的に応じて種々変更できる。実用的には、入口部分と
出口部分とからなる二つ又は二つ以上の部分からなるこ
とが好ましい。またその構造としては、ハニカム構造
型、フォーム型、板状、又は繊維状耐火物等の三次元網
目構造型、あるいは顆粒状、ペレット状等が挙げられ
る。The shape and size of the substrate of the exhaust gas purifying material are
Various changes can be made according to the purpose. Practically, it is preferable to have two or more parts including an inlet part and an outlet part. Examples of the structure include a honeycomb structure type, a foam type, a plate type, a three-dimensional network structure type such as a fibrous refractory, a granular type, a pellet type and the like.
【００１８】第二の好ましい形態は、ペレット状、顆粒
状、又は粉末状の多孔質無機酸化物に後述の触媒活性種
を担持してなる触媒を充填してなる浄化材であり、後述
の順序で配置する。ペレット状、顆粒状、又は粉末状の
多孔質無機酸化物に触媒活性種を担持する方法として、
含浸法などが挙げられる。A second preferred form is a purifying material obtained by filling a catalyst in which a pellet-like, granule-like, or powder-like porous inorganic oxide is loaded with a catalytically active species described below, in the order described below. To place. As a method of supporting a catalytically active species on a pellet-like, granular, or powdery porous inorganic oxide,
An impregnation method and the like can be mentioned.
【００１９】本発明の浄化材を構成する触媒として以下
の三つの触媒がある。 （１）第一の触媒 第一の触媒は、多孔質無機酸化物に銀及び／又は銀化合
物、又はそれらの混合物を担持してなり、排ガスの流入
側に形成される。多孔質の無機酸化物としては、多孔質
のアルミナ、シリカ、チタニア、ジルコニア、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、添加した含酸素有機化合物及び／又は排ガス中の残
留炭化水素と排ガス中の窒素酸化物との反応が効率良く
起こる。There are the following three catalysts as catalysts constituting the purifying material of the present invention. (1) First catalyst The first catalyst is formed by supporting silver and / or a silver compound or a mixture thereof on a porous inorganic oxide, and is formed on the inflow side of exhaust gas. As the porous inorganic oxide, porous alumina, silica, titania, zirconia, and their composite oxides can be used, but γ-alumina or alumina-based composite oxide is preferably used. γ
-By using the alumina or the alumina-based composite oxide, the reaction between the added oxygen-containing organic compound and / or the residual hydrocarbon in the exhaust gas and the nitrogen oxide in the exhaust gas occurs efficiently.
【００２０】多孔質の無機酸化物の比表面積は１０ｍ2
／ｇ以上であるのが好ましい。比表面積が１０ｍ2 ／ｇ
未満であると、排ガスと無機酸化物（及びこれに担持し
た銀成分）との接触面積が小さくなり、良好な窒素酸化
物の除去が行えない。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 contact area between the exhaust gas and the inorganic oxide (and the silver component carried on the exhaust gas) becomes small, and the nitrogen oxide cannot be removed well.
【００２１】多孔質無機酸化物に担持する銀及び／又は
銀化合物として、銀、銀の酸化物、銀のハロゲン化物、
硫酸銀、燐酸銀など、又はそれらの混合物が挙げられ
る。好ましい銀成分は銀の酸化物、塩化銀、又はそれら
の混合物である。担持された銀成分は微細な粒子状であ
って、10〜1000nmの平均粒径を有するのが好ましい。一
般的に、銀成分粒子の平均粒径が小さい程反応特性が良
いが、平均粒径が１０ｎｍ未満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が進みすぎるの
で、窒素酸化物の除去率が低い。一方、銀成分粒子の平
均粒径が１０００ｎｍを超えると、触媒としての反応特
性が低下し、窒素酸化物の除去率が低くなる。好ましい
銀成分粒子の平均粒径は２０〜２００ｎｍである。ここ
で、平均粒径は各粒子の直径の算術平均により求めたも
のである。As the silver and / or silver compound supported on the porous inorganic oxide, silver, silver oxide, silver halide,
Examples thereof include silver sulfate, silver phosphate, and the like, or a mixture thereof. The preferred silver component is silver oxide, silver chloride, or a mixture thereof. The supported silver component is preferably in the form of fine particles and has an average particle size of 10 to 1000 nm. Generally, the smaller the average particle size of the silver component particles is, the better the reaction characteristics are. However, if the average particle size is less than 10 nm, the oxidation reaction of the reducing agent hydrocarbon or the oxygen-containing organic compound proceeds too much. The removal rate is low. On the other hand, when the average particle diameter of the silver component particles exceeds 1000 nm, the reaction characteristics as a catalyst deteriorate, and the nitrogen oxide removal rate decreases. The average particle diameter of the silver component particles is preferably 20 to 200 nm. Here, the average particle diameter is obtained by the arithmetic mean of the diameters of the particles.
【００２２】上記したγ−アルミナ等の無機酸化物に活
性種として担持する銀成分の担持量は、無機酸化物１０
０重量％に対して０．２〜１５重量％（銀元素換算値）
とする。０．２重量％未満では窒素酸化物の除去率が低
下する。また、１５重量％を超す量の銀を担持すると含
酸素有機化合物自身の燃焼が起きやすく、窒素酸化物の
除去率はかえって低下する。好ましい銀成分の担持量は
０．５〜１０重量％である。The amount of the silver component supported on the above-mentioned inorganic oxide such as γ-alumina as an active species is the same as that of the inorganic oxide 10.
0.2 to 15% by weight with respect to 0% by weight (silver element conversion value)
And If it is less than 0.2% by weight, the removal rate of nitrogen oxides is lowered. On the other hand, if silver is loaded in an amount of more than 15% by weight, the oxygen-containing organic compound itself is easily burned, and the nitrogen oxide removal rate is rather lowered. A preferable amount of the silver component supported is 0.5 to 10% by weight.
【００２３】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５
００℃で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, a known impregnation method, a kneading method or 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, the purification material burned under the flow of nitrogen gas or hydrogen gas is 5
It is preferable to perform the oxidation treatment at 00 ° C.
【００２４】なお、上記浄化材の第一の好ましい形態で
は、浄化材基体上に設ける第一の触媒の厚さは、一般
に、基体材と、この触媒との熱膨張特性の違いから制限
される場合が多い。浄化材基体上に設ける触媒の厚さを
２００μｍ以下とするのがよい。このような厚さとすれ
ば、圧力損失を大きくせず、使用中に熱衝撃等で浄化材
が破損することを防ぐことができる。浄化材基体の表面
に触媒を形成する方法は公知のウォシュコート法、ゾル
ーゲル法、粉末法等によって行われる。In the first preferred embodiment of the purification material, the thickness of the first catalyst provided on the purification material substrate is generally limited due to the difference in thermal expansion characteristics between the substrate material and this catalyst. In many cases. The thickness of the catalyst provided on the purification material substrate is preferably 200 μm or less. With such a thickness, it is possible to prevent damage to the purification material due to thermal shock during use without increasing pressure loss. The method of forming the catalyst on the surface of the purifying material substrate is a known washcoat method, sol-gel method, powder method or the like.
【００２５】また、浄化材基体の表面上に設ける第一触
媒の量は、浄化材基体の２０〜２５０ｇ／ｌとするのが
好ましい。触媒の量が２０ｇ／ｌ未満では良好なNOx の
除去が行えない。一方、触媒の量が２５０ｇ／ｌを超え
ると除去特性はそれほど上がらず、圧力損失が大きくな
る。より好ましくは、浄化材基体の表面上に設ける第一
の触媒を浄化材基体の５０〜２００ｇ／ｌとする。Further, the amount of the first catalyst provided on the surface of the purification material substrate is preferably 20 to 250 g / l of the purification material substrate. If the amount of catalyst is less than 20 g / l, good NOx cannot be removed. On the other hand, when the amount of the catalyst exceeds 250 g / l, the removal characteristics do not improve so much and the pressure loss increases. More preferably, the first catalyst provided on the surface of the purification material substrate is 50 to 200 g / l of the purification material substrate.
【００２６】（２）第二の触媒 第二の触媒は、多孔質無機酸化物に金成分を担持してな
り、排ガスの流出側に形成される。多孔質無機酸化物と
しては、チタニア、酸化亜鉛、酸化マグネシウム、アル
ミナなどの多孔質で表面積の大きい耐熱性の無機酸化物
又はそれらを含む複合無機酸化物が挙げられる。好まし
くはチタニア及びチタニアを含む複合酸化物を用いる。
第一の触媒と同様に、多孔質の無機酸化物の比表面積は
１０ｍ2／ｇ以上であることが好ましい。(2) Second catalyst The second catalyst comprises a porous inorganic oxide carrying a gold component and is formed on the exhaust gas outflow side. Examples of the porous inorganic oxide include porous and large heat-resistant inorganic oxides such as titania, zinc oxide, magnesium oxide, and alumina, or composite inorganic oxides containing them. Preferably, titania and a composite oxide containing titania are used.
Similar to the first catalyst, the specific surface area of the porous inorganic oxide is preferably 10 m 2 / g or more.
【００２７】第二の触媒で無機酸化物に担持する金成分
の合計は、上述の多孔質の無機酸化物を基準(100重量
％) として０．０２〜５重量％（元素換算値）とする。
触媒活性種の量が前記基体に対して、５重量％を超す触
媒担持量とすると有機化合物の酸化燃焼のみが進み、窒
素酸化物の低減特性は低下することになる。また、０．
０２重量％未満では効果が十分に現れない。The total amount of gold components supported on the inorganic oxide by the second catalyst is 0.02 to 5% by weight (elemental conversion value) based on the above-mentioned porous inorganic oxide (100% by weight). .
When the amount of the catalytically active species exceeds 5% by weight with respect to the substrate, the amount of the catalyst supported will be such that only the oxidative combustion of the organic compound proceeds, and the nitrogen oxide reducing property deteriorates. Also, 0.
If it is less than 02% by weight, the effect is not sufficiently exhibited.
【００２８】また、第二の触媒の活性種として、さら
に、La、Ce等の希土類元素から選ばれた少なくとも一つ
以上の元素を２重量％以下担持することが好ましい。ま
た、Ca、Mgなどのアルカリ土類金属から選ばれた少なく
とも一つ以上の元素を２重量％以下担持することが好ま
しい。これらの元素を担持することにより、白金系の触
媒の耐熱性を向上させることができる。Further, as the active species of the second catalyst, it is preferable to further carry 2% by weight or less of at least one element selected from rare earth elements such as La and Ce. Further, it is preferable to support 2% by weight or less of at least one element selected from alkaline earth metals such as Ca and Mg. By supporting these elements, the heat resistance of the platinum-based catalyst can be improved.
【００２９】第二の触媒における活性種の担持は、公知
の含浸法、沈澱法、ゾルーゲル法等を用いることができ
る。含浸法を用いる際、塩化金酸などの水溶液に多孔質
無機酸化物を浸漬し、７０℃で乾燥後、１００〜６００
℃で段階的に昇温して焼成することによって行われる。
なお、担持成分は金属元素として表示しているが、通常
の浄化材の使用温度条件では担持成分は金属と酸化物の
状態で存在する。For supporting the active species on the second catalyst, a known impregnation method, precipitation method, sol-gel method or the like can be used. When the impregnation method is used, the porous inorganic oxide is dipped in an aqueous solution of chloroauric acid and dried at 70 ° C.
It is carried out by gradually raising the temperature at ℃ and firing.
Although the supported component is shown as a metal element, the supported component exists in the state of a metal and an oxide under normal use temperature conditions of the purification material.
【００３０】なお、上記浄化材の第一の好ましい形態で
は、浄化材基体上に設ける第二の触媒の厚さを１００μ
ｍ以下とするのがよい。また、浄化材基体の表面上に設
ける第二の触媒の量は、浄化材基体の２５〜２５０ｇ／
ｌとするのが好ましい。第二の触媒を浄化材基体にコー
トする方法は既述した第一の触媒の方法と同じである。In the first preferred embodiment of the purification material, the thickness of the second catalyst provided on the purification material substrate is 100 μm.
It is preferably m or less. Further, the amount of the second catalyst provided on the surface of the purification material substrate is 25 to 250 g / of the purification material substrate.
It is preferable that it is 1. The method of coating the purifying material substrate with the second catalyst is the same as the method of the first catalyst described above.
【００３１】（３）第三の触媒 第三の触媒は、多孔質無機酸化物に触媒活性種を担持し
てなり、排ガスの流出側に形成される。多孔質無機酸化
物としては、γ−アルミナ及びその酸化物（γ−アルミ
ナ−チタニア、γ−アルミナ−シリカ、γ−アルミナ−
ジルコニア等）、ジルコニア、チタニア−ジルコニアな
どの多孔質で表面積の大きい耐熱性のセラミックスが挙
げられる。好ましくはγ−アルミナ、チタニア、ジルコ
ニア及びそれらを含む複合酸化物を用いる。第一の触媒
と同様に、多孔質の無機酸化物の比表面積は１０ｍ2 ／
ｇ以上であることが好ましい。(3) Third Catalyst The third catalyst comprises a porous inorganic oxide carrying a catalytically active species and is formed on the exhaust gas outflow side. As the porous inorganic oxide, γ-alumina and its oxide (γ-alumina-titania, γ-alumina-silica, γ-alumina-
Examples thereof include heat-resistant ceramics having a large surface area such as zirconia), zirconia, and titania-zirconia. Preferably, γ-alumina, titania, zirconia and a composite oxide containing them are used. Like the first catalyst, the porous inorganic oxide has a specific surface area of 10 m 2 /
It is preferably at least g.
【００３２】上記第三の触媒の活性種としては、Pt、P
d、Ru、Rh、Irからなる群より選ばれた少なくとも１種
の元素を用いる。特に、ＰｔとＲｈ；ＰｄとＲｈ；Ｐ
ｔ、ＰｄとＲｈの組み合わせは効果的である。第三の触
媒で無機酸化物に担持する活性種の合計は、上述の多孔
質の無機酸化物を基準(100重量％) として０．０２〜５
重量％とする。触媒活性種の量が前記基体に対して、５
重量％を超す触媒担持量とすると含酸素有機化合物の酸
化燃焼のみが進み、窒素酸化物の低減特性は低下するこ
とになる。また、０．０２重量％未満では効果が十分に
現れない。The active species of the third catalyst are Pt, P
At least one element selected from the group consisting of d, Ru, Rh, and Ir is used. In particular, Pt and Rh; Pd and Rh; P
The combination of t, Pd and Rh is effective. The total amount of active species supported on the inorganic oxide by the third catalyst is 0.02 to 5 based on the above-mentioned porous inorganic oxide (100% by weight).
Weight% The amount of catalytically active species is 5 with respect to the substrate.
When the amount of the catalyst supported exceeds 5% by weight, only the oxidative combustion of the oxygen-containing organic compound proceeds, and the nitrogen oxide reducing property deteriorates. Further, if it is less than 0.02% by weight, the effect is not sufficiently exhibited.
【００３３】また、第三の触媒の活性種として、さら
に、La、Ce等の希土類元素から選ばれた少なくとも一つ
以上の元素を１０重量％以下担持することが好ましい。
希土類元素を担持することにより、白金系の触媒の耐熱
性を向上させることができる。Further, as the active species of the third catalyst, it is preferable that 10% by weight or less of at least one element selected from rare earth elements such as La and Ce is further supported.
By supporting the rare earth element, the heat resistance of the platinum-based catalyst can be improved.
【００３４】第三の触媒における活性種の担持は、公知
の含浸法、沈澱法、ゾルーゲル法等を用いることができ
る。含浸法を用いる際、触媒活性種元素の炭酸塩、塩酸
塩、硝酸塩、酢酸塩、水酸化物等の水溶液に多孔質無機
酸化物を浸漬し、７０℃で乾燥後、１００〜７００℃で
段階的に昇温して焼成することによって行われる。な
お、担持成分は金属元素として表示しているが、通常の
浄化材の使用温度条件では担持成分は金属と酸化物の状
態で存在する。For supporting the active species on the third catalyst, a known impregnation method, precipitation method, sol-gel method or the like can be used. When using the impregnation method, the porous inorganic oxide is immersed in an aqueous solution of a carbonate, a hydrochloride, a nitrate, an acetate, or a hydroxide of a catalytically active element, dried at 70 ° C., and then staged at 100 to 700 ° C. The temperature is increased and the firing is performed. Although the supported component is shown as a metal element, the supported component exists in the state of a metal and an oxide under normal use temperature conditions of the purification material.
【００３５】なお、上記浄化材の第一の好ましい形態で
は、浄化材基体上に設ける第三の触媒の厚さを１００μ
ｍ以下とするのがよい。また、浄化材基体の表面上に設
ける第三の触媒の量は、浄化材基体の２５〜２５０ｇ／
ｌとするのが好ましい。第三の触媒を浄化材基体にコー
トする方法は既述した第一の触媒の方法と同じである。In the first preferred embodiment of the purification material, the thickness of the third catalyst provided on the purification material substrate is 100 μm.
It is preferably m or less. Further, the amount of the third catalyst provided on the surface of the purification material substrate is 25 to 250 g / of the purification material substrate.
It is preferable that it is 1. The method for coating the purifying material substrate with the third catalyst is the same as the method for the first catalyst described above.
【００３６】本発明の浄化材は上記触媒を配置して用い
る。具体的には、本発明の第一の浄化材は、排ガス流入
側に第一の触媒、排ガス流出側に第二の触媒を設置して
なる。本発明の第二の浄化材は、第一の触媒と第二の触
媒を混合してなる。本発明の第三の浄化材は、排ガス流
入側から流出側に順に第一の触媒、第二の触媒、第三の
触媒を設置してなる。本発明の第四の浄化材は、第一の
触媒、第二の触媒、及び第三の触媒を混合してなる。In the purifying material of the present invention, the above catalyst is arranged and used. Specifically, the first purification material of the present invention comprises a first catalyst on the exhaust gas inflow side and a second catalyst on the exhaust gas outflow side. The second purifying material of the present invention is a mixture of the first catalyst and the second catalyst. The third purification material of the present invention comprises a first catalyst, a second catalyst, and a third catalyst which are installed in this order from the exhaust gas inflow side to the outflow side. The fourth purifying material of the present invention is a mixture of the first catalyst, the second catalyst, and the third catalyst.
【００３７】本発明においては、第一の触媒と、第二の
触媒との重量比は、５：１〜１：５とするのが好まし
い。比率が１：５未満である（第一の触媒が少ない）
と、２５０〜６００℃の広い温度範囲で全体的に窒素酸
化物の浄化率が低下する。一方、比率が５：１を超える
（第一の触媒が多い）と、４００℃以下における窒素酸
化物の浄化能が大きくならない。すなわち、比較的低温
での還元剤と窒素酸化物との反応が十分に進行しない。
より好ましい第一触媒と第二触媒の重量比は４：１〜
１：４である。In the present invention, the weight ratio of the first catalyst to the second catalyst is preferably 5: 1 to 1: 5. The ratio is less than 1: 5 (less first catalyst)
Then, the purification rate of nitrogen oxides is generally lowered in a wide temperature range of 250 to 600 ° C. On the other hand, when the ratio exceeds 5: 1 (the amount of the first catalyst is large), the purifying ability of nitrogen oxides at 400 ° C or lower does not increase. That is, the reaction between the reducing agent and the nitrogen oxide does not proceed sufficiently at a relatively low temperature.
More preferable weight ratio of the first catalyst to the second catalyst is from 4: 1 to
It is 1: 4.
【００３８】また、第一の触媒と、第三の触媒との重量
比は、５：１〜１：５とするのが好ましい。比率が１：
５未満である（第一の触媒が少ない）と、窒素酸化物の
浄化率が低下する。一方、比率が５：１を超える（第一
の触媒が多い）と、４００℃以下における窒素酸化物の
浄化能が大きくならない。より好ましい第一触媒と第三
触媒の重量比は４：１〜１：４である。The weight ratio of the first catalyst to the third catalyst is preferably 5: 1 to 1: 5. Ratio is 1:
When it is less than 5 (the amount of the first catalyst is small), the purification rate of nitrogen oxides decreases. On the other hand, when the ratio exceeds 5: 1 (the amount of the first catalyst is large), the purifying ability of nitrogen oxides at 400 ° C or lower does not increase. A more preferable weight ratio of the first catalyst to the third catalyst is 4: 1 to 1: 4.
【００３９】上述した構成の浄化材を用いれば、１５０
〜６５０℃の広い温度領域において、水分を１０％程度
を含む排ガスでも、良好な窒素酸化物の除去を行うこと
ができる。If the purifying material having the above-mentioned structure is used,
In a wide temperature range of up to 650 ° C., good nitrogen oxides can be removed even with exhaust gas containing about 10% of water.
【００４０】次に、本発明の方法について説明する。ま
ず、上記本発明の排ガス浄化材を排ガス導管の途中に設
置する。Next, the method of the present invention will be described. First, the exhaust gas purifying material of the present invention is installed in the middle of an exhaust gas conduit.
【００４１】排ガス中には、残留炭化水素としてエチレ
ン、プロピレン等がある程度は含まれるが、一般に排ガ
ス中のNOx を還元するのに十分な量ではないので、外部
から炭化水素及び／又は含酸素有機化合物からなる還元
剤を排ガス中に導入する。還元剤の導入位置は、浄化材
を設置した位置より上流側である。The exhaust gas contains ethylene, propylene and the like as residual hydrocarbons to some extent, but since it is generally not sufficient to reduce NOx in the exhaust gas, hydrocarbons and / or oxygen-containing organic substances are externally added. A reducing agent consisting of a compound is introduced into the exhaust gas. The introduction position of the reducing agent is upstream of the position where the purification material is installed.
【００４２】外部から導入する炭化水素としては、標準
状態でガス状又は液体状のアルカン、アルケン及び／又
はアルキンを用いることができる。特にアルカン又はア
ルケンの場合では炭素数３以上が好ましい。標準状態で
液体状の炭化水素としては、具体的に、軽油、セタン、
ヘプタン、灯油等の炭化水素が挙げられる。含酸素有機
化合物として、エタノール等の炭素数２以上のアルコー
ル類を用いることができる。As the hydrocarbon introduced from the outside, a gaseous or liquid alkane, alkene and / or alkyne in a standard state can be used. Particularly in the case of alkane or alkene, the number of carbon atoms is preferably 3 or more. As the liquid hydrocarbon in the standard state, specifically, light oil, cetane,
Examples include hydrocarbons such as heptane and kerosene. As the oxygen-containing organic compound, alcohols having 2 or more carbon atoms such as ethanol can be used.
【００４３】外部から導入する含酸素有機化合物の量
は、重量比（添加する還元剤の重量／排ガス中の窒素酸
化物の重量）が０．１〜５となるようにするのが好まし
い。この重量比が０．１未満であると、窒素酸化物の除
去率が大きくならない。一方、５を超えると、燃費悪化
につながる。The amount of the oxygen-containing organic compound introduced from the outside is preferably such that the weight ratio (weight of reducing agent added / weight of nitrogen oxide in exhaust gas) is 0.1 to 5. If this weight ratio is less than 0.1, the nitrogen oxide removal rate does not increase. On the other hand, when it exceeds 5, fuel consumption is deteriorated.
【００４４】本発明では、炭化水素、含酸素有機化合物
等による窒素酸化物の還元除去を効率的に進行させるた
めに排ガスと浄化材中の各触媒との接触時間は０．００
５ｇ・秒／ml以上とする。触媒との接触時間が０．００
５ｇ・秒／ml未満であると、窒素酸化物の還元反応が十
分に起こらず、窒素酸化物の除去率が低下する。好まし
くは接触時間が０．００６ｇ・秒／ml以上とする。In the present invention, the contact time between the exhaust gas and each catalyst in the purifying material is 0.00 in order to efficiently reduce and remove nitrogen oxides by hydrocarbons, oxygen-containing organic compounds and the like.
5g · sec / ml or more. Contact time with catalyst 0.00
If it is less than 5 g · sec / ml, the reduction reaction of nitrogen oxides does not sufficiently occur, and the removal rate of nitrogen oxides decreases. The contact time is preferably 0.006 g · sec / ml or more.
【００４５】また、本発明では、含酸素有機化合物と窒
素酸化物とが反応する部位である浄化材設置部位におけ
る排ガスの温度を１５０〜６５０℃に保つ。排ガスの温
度が１５０℃未満であると還元剤と窒素酸化物との反応
が進行せず、良好な窒素酸化物の除去を行うことができ
ない。一方、６５０℃を超す温度とすると含酸素有機化
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、３００〜６００℃であ
る。Further, in the present invention, the temperature of the exhaust gas at the site where the purifying material is installed, which is the site where the oxygen-containing organic compound reacts with the nitrogen oxide, is maintained at 150 to 650 ° C. If the temperature of the exhaust gas is less than 150 ° C., the reaction between the reducing agent and the nitrogen oxide does not proceed, and the nitrogen oxide cannot be removed satisfactorily. On the other hand, if the temperature exceeds 650 ° C., the oxygen-containing organic compound itself starts to burn, and the nitrogen oxide cannot be reduced and removed. A preferable exhaust gas temperature is 300 to 600 ° C.
【００４６】[0046]
【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
６mm、比表面積２００ｍ2 ／ｇ）５ｇに、硝酸銀水溶液
を用いて銀を２重量％担持し、乾燥後、空気中で６００
℃まで段階的に焼成し、触媒１を調製した。同様に、ペ
レット状チタニア（直径１．５mm、長さ約６mm、比表面
積２０ｍ2 ／ｇ）５ｇに塩化金酸水溶液を用いて、金を
１重量％担持し、乾燥後、空気中で７００℃まで焼成
し、触媒２を調製した。The present invention will be described in more detail by the following specific examples. Example 1 5 g of commercially available pelletized γ-alumina (diameter: 1.5 mm, length: about 6 mm, specific surface area: 200 m 2 / g) was loaded with 2% by weight of silver using an aqueous solution of silver nitrate, dried, and then dried in air. 600
Catalyst 1 was prepared by calcining stepwise to ℃. Similarly, 5 g of pelletized titania (diameter 1.5 mm, length about 6 mm, specific surface area 20 m 2 / g) was loaded with 1% by weight of gold using an aqueous solution of chloroauric acid, dried, and then dried at 700 ° C. in air. And was calcined to prepare catalyst 2.
【００４７】銀系触媒３．７ｇと金系触媒１．８ｇを混
合した浄化材を反応管内にセットした。次に、表１に示
す組成のガス（一酸化窒素、一酸化炭素、酸素、プロピ
レン、及び窒素）を毎分４．４リットル（標準状態）の
流量で流して（全体の見かけ空間速度約２０，０００ｈ
-1、銀系触媒と金触媒の接触時間はそれぞれ０．０５、
０．０２５秒・ｇ／ml）、反応管内の排ガス温度を２０
０〜７００℃の範囲に保ち、プロピレンと窒素酸化物と
を反応させた。A purification material in which 3.7 g of a silver catalyst and 1.8 g of a gold catalyst were mixed was set in the reaction tube. Next, a gas having a composition shown in Table 1 (nitrogen monoxide, carbon monoxide, oxygen, propylene, and nitrogen) was flowed at a flow rate of 4.4 liters per minute (standard state) (total apparent space velocity of about 20). 1,000 h
-1 , the contact time of silver catalyst and gold catalyst is 0.05,
0.025 seconds ・ g / ml), the exhaust gas temperature in the reaction tube is set to 20
The temperature was kept in the range of 0 to 700 ° C., and propylene was reacted with nitrogen oxide.
【００４８】反応管通過後のガスの窒素酸化物の濃度を
化学発光式窒素酸化物分析計により測定し、窒素酸化物
の除去率を求めた。結果を図１に示す。The nitrogen oxide concentration of the gas after passing through the reaction tube was measured by a chemiluminescence type nitrogen oxide analyzer to determine the nitrogen oxide removal rate. The results are shown in Fig. 1.
【００４９】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％ 水分 10 容量％ プロピレン 1600 ppm 窒素 残部Table 1 Component Concentration Nitric oxide 800 ppm Carbon monoxide 100 ppm Oxygen 10% by volume Moisture 10% by volume Propylene 1600 ppm Nitrogen balance
【００５０】実施例２ 硝酸銀水溶液を用いて粉末状γ−アルミナ（比表面積２
００ｍ2 ／ｇ）に銀が２重量％担持されている触媒作成
し、この触媒約１．０ｇを市販のコージェライト製ハニ
カム状成形体（直径３０mm、長さ１２．６mm、４００セ
ル／平方インチ）に、コートし、乾燥後、６００℃まで
段階的に焼成し、浄化材を調製した。また、同様のハニ
カム状成形体（長さ６mm）に塩化金酸溶液を用いて、粉
末状チタニア（比表面積５０ｍ2 ／ｇ）に金が１重量％
担持されている触媒０．４ｇをコートし、乾燥後、７０
０℃まで焼成し、浄化材を調製した。排ガスの流入側に
銀系浄化材、流出側に金浄化材になるように、反応管内
にセットした。表１に示す成分のガスを用い、実施例１
と同様の条件でこの浄化材を評価した（全体の見かけ空
間速度２０，０００ｈ-1）。実験結果を図１に示す。 Example 2 Powdery γ-alumina (specific surface area 2
A catalyst having 2% by weight of silver supported on 00 m 2 / g) was prepared, and about 1.0 g of this catalyst was used as a commercially available cordierite honeycomb molded body (diameter 30 mm, length 12.6 mm, 400 cells / square inch). ) Was coated, dried and then fired stepwise to 600 ° C. to prepare a purification material. In addition, using a chloroauric acid solution for the same honeycomb-shaped compact (length 6 mm), 1% by weight of gold was added to powdery titania (specific surface area 50 m 2 / g).
After coating 0.4 g of the supported catalyst and drying, 70
The purification material was prepared by firing to 0 ° C. It was set in the reaction tube so that the inflow side of the exhaust gas was a silver-based purification material and the outflow side was a gold purification material. Example 1 using the gases of the components shown in Table 1
This purification material was evaluated under the same conditions as in (total apparent space velocity 20,000 h −1 ). The experimental results are shown in FIG.
【００５１】実施例３ 実施例２で作成した浄化材を用いて、表１に示すガス組
成の内プロピレンに換えて軽油（添加量は窒素酸化物の
質量の３倍）を用いて、実施例２と同様な方法で評価し
た。実験結果を図１に示す。 Example 3 Using the purification material prepared in Example 2, light oil (addition amount was 3 times the mass of nitrogen oxide) was used instead of propylene in the gas composition shown in Table 1. Evaluation was performed in the same manner as in 2. The experimental results are shown in FIG.
【００５２】比較例１ 実施例１と同様な方法で、γ−アルミナペレット１０ｇ
に銀を２重量％担持した浄化材を作成した。この浄化材
３．６ｇを反応管にセットし、表１に示す組成のガスで
評価した。実験結果を図１に示す。 Comparative Example 1 In the same manner as in Example 1, 10 g of γ-alumina pellets
As a result, a purifying material carrying 2% by weight of silver was prepared. 3.6 g of this purification material was set in a reaction tube, and the gas having the composition shown in Table 1 was evaluated. The experimental results are shown in FIG.
【００５３】以上からわかるように、実施例１〜３にお
いては、広い排ガス温度範囲で窒素酸化物の良好な除去
がみられた。一方、比較例１においては、窒素酸化物除
去の温度範囲が狭かった。As can be seen from the above, in Examples 1 to 3, good removal of nitrogen oxides was observed in a wide exhaust gas temperature range. On the other hand, in Comparative Example 1, the temperature range for removing nitrogen oxides was narrow.
【００５４】実施例４ 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
用いて銀を２重量％担持し、乾燥後、６００℃まで段階
的に焼成し、第一の触媒を調製した。また、ペレット状
チタニア（直径1.5mm 、長さ約6 mm、比表面積２０ｍ2
／ｇ）５ｇに塩化金酸水溶液を用いて、金を１重量％担
持し、乾燥後、空気中で７００℃まで焼成し、第二の触
媒を調製した。さらに、第一の触媒と同様のペレット状
γ−アルミナ（直径1.5mm 、長さ約6 mm、比表面積２０
０ｍ2 ／ｇ）５ｇに塩化白金酸水溶液を用いて、Ptを２
重量％担持し、乾燥後、空気中で７００℃まで焼成し、
第三の触媒を調製した。 Example 4 Commercially available pelletized γ-alumina (diameter 1.5 mm, length about 6)
2% by weight of silver was supported on 5 g of a glass plate (mm, specific surface area: 200 m 2 / g) using an aqueous solution of silver nitrate, dried and calcined stepwise to 600 ° C. to prepare a first catalyst. Also, pelletized titania (diameter 1.5 mm, length about 6 mm, specific surface area 20 m 2
/ G) 5 g of a chloroauric acid aqueous solution was used to support 1% by weight of gold, and after drying, calcination was performed in air to 700 ° C. to prepare a second catalyst. Furthermore, the same pelletized γ-alumina as the first catalyst (diameter 1.5 mm, length about 6 mm, specific surface area 20
0m 2 / g) 5g of chloroplatinic acid aqueous solution, Pt 2
Wt% loading, dried, then baked in air to 700 ℃,
A third catalyst was prepared.
【００５５】銀系第一の触媒３．７ｇ、金系第二の触媒
１．８ｇ、Pt系第三の触媒１．８ｇを混合して浄化材と
し、反応管内にセットした。次に、表１に示す組成のガ
ス（一酸化炭素、一酸化窒素、酸素、プロピレン、及び
窒素）を毎分４．４リットル（標準状態）の流量で流し
て（全体の見かけ空間速度約１５，０００ｈ-1、銀系触
媒、金系触媒とPt系触媒の接触時間はそれぞれ０．０
５、０．０２５、０．０２５秒・ｇ／ml）、反応管内の
排ガス温度を２００〜７００℃の範囲に保ち、プロピレ
ンと窒素酸化物とを反応させた。A silver-based first catalyst (3.7 g), a gold-based second catalyst (1.8 g) and a Pt-based third catalyst (1.8 g) were mixed to prepare a purification material, which was set in the reaction tube. Next, a gas having the composition shown in Table 1 (carbon monoxide, nitric oxide, oxygen, propylene, and nitrogen) was flowed at a flow rate of 4.4 liters per minute (standard state) (total apparent space velocity of about 15 2,000h -1 , contact time of silver-based catalyst, gold-based catalyst and Pt-based catalyst is 0.0
5, 0.025, 0.025 sec.g / ml), the exhaust gas temperature in the reaction tube was kept in the range of 200 to 700 ° C., and propylene was reacted with nitrogen oxides.
【００５６】反応管通過後のガスの窒素酸化物の濃度を
化学発光式窒素酸化物分析計により測定し、窒素酸化物
の除去率を求めた。結果を図２に示す。The nitrogen oxide concentration of the gas after passing through the reaction tube was measured by a chemiluminescence type nitrogen oxide analyzer to determine the nitrogen oxide removal rate. The results are shown in Figure 2.
【００５７】実施例５ 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、４００セル／平方インチ）に、
硝酸銀水溶液を用いて粉末状γ−アルミナ（比表面積２
００ｍ2 ／ｇ）に銀が２重量％担持されている触媒約１
ｇをコートし、乾燥後、６００℃まで段階的に焼成し、
浄化材を調製した。また、同様のハニカム状成形体（長
さ６mm）に、粉末状γ−アルミナにPtが１重量％担持さ
れている触媒０．４ｇをコートし、乾燥後、７００℃ま
で焼成し、浄化材を調製した。さらに、同様のハニカム
状成形体（長さ６mm）に塩化金酸水溶液を用いて、粉末
状チタニア（比表面積５０ｍ2 ／ｇ）に金が１重量％担
持されている触媒０．４ｇをコートし、乾燥後、７００
℃まで焼成し、浄化材を調製した。排ガスの流入側か
ら、銀系浄化材、金系浄化材、Pt系浄化材の順に組み合
わせて、反応管内にセットし、表１と同組成のガスで実
施例４と同じ方法で評価した（全体の見かけ空間速度約
１５，０００ｈ-1）。実験結果を図２に示す。 Example 5 Commercially available cordierite honeycomb-shaped molded product (diameter: 30 m)
m, length about 12.6 mm, 400 cells / square inch),
Powdery γ-alumina (specific surface area 2
About 1 catalyst with 2% by weight of silver loaded on 00 m 2 / g)
g, dried, and fired stepwise to 600 ° C.,
A purification material was prepared. In addition, a similar honeycomb shaped body (length 6 mm) was coated with 0.4 g of a catalyst in which 1 wt% of Pt was supported on powdery γ-alumina, dried, and fired to 700 ° C to obtain a purification material. Prepared. Further, 0.4 g of a catalyst in which 1% by weight of gold was supported on powdery titania (specific surface area 50 m 2 / g) was coated on the same honeycomb-shaped molded body (length 6 mm) using an aqueous chloroauric acid solution. , After drying, 700
The purification material was prepared by firing to ℃. From the inflow side of the exhaust gas, a silver-based purification material, a gold-based purification material, and a Pt-based purification material were combined in this order, set in a reaction tube, and evaluated with the same composition as in Table 1 by the same method as in Example 4 (total). Apparent space velocity of about 15,000 h -1 ). The experimental results are shown in FIG.
【００５８】実施例６ 実施例５で作成した浄化材を用いて、表１に示すガス組
成の内プロピレンに換えて軽油（添加量は窒素酸化物の
質量の３倍）を用いて、実施例５と同様な方法で評価し
た。実験結果を図２に示す。 Example 6 Using the purification material prepared in Example 5, light oil (addition amount was 3 times the mass of nitrogen oxide) was used instead of propylene in the gas composition shown in Table 1. Evaluation was made in the same manner as in 5. The experimental results are shown in FIG.
【００５９】比較例２ 実施例４と同様な方法で、γ−アルミナペレット１０ｇ
に銀を５重量％担持してなる浄化材３．６ｇを反応管に
セットし、表１に示す組成のガスで評価した。実験結果
を図２に示す。 Comparative Example 2 In the same manner as in Example 4, 10 g of γ-alumina pellets
3.6 g of a purifying material containing 5% by weight of silver was set in a reaction tube, and the gas having the composition shown in Table 1 was evaluated. The experimental results are shown in FIG.
【００６０】以上からわかるように、実施例４〜６にお
いては、広い排ガス温度範囲で窒素酸化物の良好な除去
がみられた。一方、比較例２においては、窒素酸化物除
去の温度範囲が狭かった。As can be seen from the above, in Examples 4 to 6, good removal of nitrogen oxides was observed in a wide exhaust gas temperature range. On the other hand, in Comparative Example 2, the nitrogen oxide removal temperature range was narrow.
【００６１】実施例７ 市販のペレット状γ−アルミナ（直径１．５mm、長さ約
６mm、比表面積２００ｍ2 ／ｇ）５ｇを２０分間硝酸銀
水溶液（水２０ｍｌに硝酸銀０．６７ｇを溶かした溶
液）に浸漬したあと、空気中、８０℃で２時間と、乾燥
窒素気流下、１８０℃で２時間乾燥し、硝酸銀を成形体
に担持した。次に、乾燥窒素気流下、室温まで冷却した
あと、上記γ−アルミナ成形体を塩化アンモニウム水溶
液（水２０ｍｌに塩化アンモニウム０．５ｇを溶かした
溶液）に１２時間浸漬し、硝酸銀を塩化銀に変換した。
そして、上記γ−アルミナ成形体を塩化アンモニウム溶
液から取り出し、空気中、８０℃で２時間乾燥後、酸素
１０％を含む窒素気流下、毎分２．５℃で５５０℃まで
昇温したあと、５５０℃で５時間焼成し、γ−アルミナ
成形体に対して４重量％（銀元素換算値）の銀を塩化銀
の形で担持し、銀系触媒を調製した。次に、ペレット状
チタニア（直径１．５mm、長さ約６mm、比表面積２０ｍ
2 ／ｇ）５ｇに塩化金酸水溶液を用いて、金を１重量％
担持し、乾燥後、空気中で７００℃まで焼成し、金系触
媒を調製した。 Example 7 5 g of commercially available pelletized γ-alumina (diameter: 1.5 mm, length: about 6 mm, specific surface area: 200 m 2 / g) was added for 20 minutes in an aqueous silver nitrate solution (solution in which 0.67 g of silver nitrate was dissolved in 20 ml of water). After that, it was dried in air at 80 ° C. for 2 hours and in a dry nitrogen stream at 180 ° C. for 2 hours to support silver nitrate on the molded body. Next, after cooling to room temperature under a dry nitrogen stream, the γ-alumina molded body was immersed in an ammonium chloride aqueous solution (a solution of 0.5 g of ammonium chloride dissolved in 20 ml of water) for 12 hours to convert silver nitrate into silver chloride. did.
Then, the γ-alumina molded body was taken out from the ammonium chloride solution, dried in air at 80 ° C. for 2 hours, and then heated to 550 ° C. at 2.5 ° C./min under a nitrogen stream containing 10% oxygen, The mixture was calcined at 550 ° C. for 5 hours, and 4% by weight (silver element conversion value) of silver was supported in the form of silver chloride on the γ-alumina compact to prepare a silver-based catalyst. Next, pelletized titania (diameter 1.5mm, length about 6mm, specific surface area 20m
2 / g) 5 g of an aqueous solution of chloroauric acid is used, and 1 wt% of gold
After being supported, dried and calcined in air to 700 ° C., a gold-based catalyst was prepared.
【００６２】銀系触媒３．７ｇと金系触媒１．８ｇを混
合した浄化材を反応管内にセットした。次に、表２に示
す組成のガス（一酸化窒素、一酸化炭素、酸素、プロピ
レン、及び窒素）を毎分４．４リットル（標準状態）の
流量で流して（全体の見かけ空間速度約２０，０００ｈ
-1、銀系触媒と金触媒の接触時間はそれぞれ０．０５、
０．０２５秒・ｇ／ml）、反応管内の排ガス温度を２０
０〜７００℃の範囲に保ち、プロピレンと窒素酸化物と
を反応させた。A purification material in which 3.7 g of a silver catalyst and 1.8 g of a gold catalyst were mixed was set in the reaction tube. Next, a gas having the composition shown in Table 2 (nitrogen monoxide, carbon monoxide, oxygen, propylene, and nitrogen) was caused to flow at a flow rate of 4.4 liters per minute (standard state) (total apparent space velocity of about 20). 1,000 h
-1 , the contact time of silver catalyst and gold catalyst is 0.05,
0.025 seconds ・ g / ml), the exhaust gas temperature in the reaction tube is set to 20
The temperature was kept in the range of 0 to 700 ° C., and propylene was reacted with nitrogen oxide.
【００６３】反応管通過後のガスの窒素酸化物の濃度を
化学発光式窒素酸化物分析計により測定し、窒素酸化物
の除去率を求めた。結果を図３に示す。The nitrogen oxide concentration of the gas after passing through the reaction tube was measured by a chemiluminescence type nitrogen oxide analyzer to determine the nitrogen oxide removal rate. The results are shown in Fig. 3.
【００６４】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％ 水分 10 容量％ プロピレン 1600 ppm 窒素 残部Table 2 Concentration of constituents Nitric oxide 800 ppm Carbon monoxide 100 ppm Oxygen 10% by volume Moisture 10% by volume Propylene 1600 ppm Nitrogen balance
【００６５】実施例８ 実施例７で作成した浄化材を用いて、表２に示すガス組
成の内プロピレンに換えてエタノール（添加量は窒素酸
化物の質量の３倍）を用いて、実施例７と同様な方法で
評価した。実験結果を図３に示す。 Example 8 Using the purification material prepared in Example 7, ethanol was used instead of propylene in the gas composition shown in Table 2 (the addition amount was 3 times the mass of nitrogen oxide). Evaluation was performed in the same manner as in 7. The experimental results are shown in FIG.
【００６６】実施例９ 実施例７と同じ方法で硝酸銀水溶液を用いて粉末状γ−
アルミナ（比表面積２００ｍ2 ／ｇ）に塩化銀が４重量
％（銀元素換算値）担持されている触媒作成し、この触
媒約１．０ｇを市販のコージェライト製ハニカム状成形
体（直径３０mm、長さ１２．６mm、４００セル／平方イ
ンチ）に、コートし、乾燥後、６００℃まで段階的に焼
成し、銀系浄化材を調製した。また、同様のハニカム状
成形体（長さ６mm）に塩化金酸溶液を用いて、粉末状チ
タニア（比表面積５０ｍ2 ／ｇ）に金が１重量％担持さ
れている触媒０．４ｇをコートし、乾燥後、７００℃ま
で焼成し、金系浄化材を調製した。排ガスの流入側に銀
系浄化材、流出側に金浄化材になるように、反応管内に
セットした。表２に示す成分のガスを用い、実施例７と
同様の条件でこの浄化材を評価した（全体の見かけ空間
速度２０，０００ｈ-1）。実験結果を図３に示す。 Example 9 In the same manner as in Example 7, an aqueous silver nitrate solution was used to obtain powdery γ-.
A catalyst was prepared by supporting 4% by weight of silver chloride on silver (specific surface area 200 m 2 / g) (converted into silver element), and about 1.0 g of this catalyst was commercially available and made into a cordierite honeycomb molded body (diameter 30 mm, A length of 12.6 mm, 400 cells / in 2) was coated, dried, and fired stepwise to 600 ° C. to prepare a silver-based purification material. Further, a similar honeycomb shaped body (length 6 mm) was coated with 0.4 g of a catalyst in which 1 wt% of gold was supported on powdery titania (specific surface area 50 m 2 / g) using a chloroauric acid solution. After drying, it was baked to 700 ° C. to prepare a gold-based purification material. It was set in the reaction tube so that the inflow side of the exhaust gas was a silver-based purification material and the outflow side was a gold purification material. This purification material was evaluated under the same conditions as in Example 7 using the gases having the components shown in Table 2 (total apparent space velocity 20,000 h −1 ). The experimental results are shown in FIG.
【００６７】実施例１０ 実施例９で作成した浄化材を用いて、表２に示すガス組
成の内プロピレンに換えて軽油（添加量は窒素酸化物の
質量の３倍）を用いて、実施例９と同様な方法で評価し
た。実験結果を図３に示す。 Example 10 Using the purifying material prepared in Example 9, light oil (addition amount was 3 times the mass of nitrogen oxide) was used instead of propylene in the gas composition shown in Table 2. Evaluation was carried out in the same manner as in No. 9. The experimental results are shown in FIG.
【００６８】実施例１１ 実施例９で作成した浄化材を用いて、表２に示すガス組
成の内プロピレンに換えてエタノール（添加量は窒素酸
化物の質量の３倍）を用いて、実施例９と同様な方法で
評価した。実験結果を図３に示す。 Example 11 Using the purifying material prepared in Example 9, ethanol was used instead of propylene in the gas composition shown in Table 2 (the addition amount was 3 times the mass of nitrogen oxide). Evaluation was carried out in the same manner as in No. 9. The experimental results are shown in FIG.
【００６９】比較例３ 実施例７と同様な方法で、γ−アルミナペレット１０ｇ
に塩化銀を２重量％担持した浄化材を作成した。この浄
化材３．６ｇを反応管にセットし、表２に示す組成のガ
スで評価した。実験結果を図３に示す。 Comparative Example 3 In the same manner as in Example 7, 10 g of γ-alumina pellets
A purifying material carrying 2% by weight of silver chloride was prepared. 3.6 g of this purification material was set in a reaction tube, and the gas having the composition shown in Table 2 was evaluated. The experimental results are shown in FIG.
【００７０】以上からわかるように、実施例７〜１１に
おいては、広い排ガス温度範囲で窒素酸化物の良好な除
去がみられた。一方、比較例３においては、窒素酸化物
除去の温度範囲が狭かった。As can be seen from the above, in Examples 7 to 11, good removal of nitrogen oxides was observed in a wide exhaust gas temperature range. On the other hand, in Comparative Example 3, the nitrogen oxide removal temperature range was narrow.
【００７１】実施例１２ 実施例７と同様な方法で市販のペレット状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塩化銀を４重量％（銀元
素換算値）担持し、銀系触媒を調製した。また、ペレッ
ト状チタニア（直径1.5mm 、長さ約6 mm、比表面積２０
ｍ2 ／ｇ）５ｇに塩化金酸水溶液を用いて、金を１重量
％担持し、乾燥後、空気中で７００℃まで焼成し、金系
触媒を調製した。さらに、銀系触媒と同様のペレット状
γ−アルミナ（直径1.5mm 、長さ約6 mm、比表面積２０
０ｍ2 ／ｇ）５ｇに塩化白金酸水溶液を用いて、Ptを２
重量％担持し、乾燥後、空気中で７００℃まで焼成し、
白金系触媒を調製した。 Example 12 Commercially available pelletized γ-alumina (diameter: 1.5 mm, length: about 6 mm, specific surface area: 200 m 2 / g) was prepared in the same manner as in Example 7.
A silver-based catalyst was prepared by supporting 4% by weight (silver element conversion value) of silver chloride on 5 g using an aqueous solution of silver nitrate. Also, pelletized titania (diameter 1.5 mm, length about 6 mm, specific surface area 20
5% of m 2 / g) was loaded with 1% by weight of gold using an aqueous solution of chloroauric acid, dried and calcined in air to 700 ° C. to prepare a gold-based catalyst. Furthermore, the same pelletized γ-alumina as the silver-based catalyst (diameter 1.5 mm, length about 6 mm, specific surface area 20
0m 2 / g) 5g of chloroplatinic acid aqueous solution, Pt 2
Wt% loading, dried, then baked in air to 700 ℃,
A platinum-based catalyst was prepared.
【００７２】銀系第一の触媒３．７ｇ、金系第二の触媒
１．８ｇ、白金系第三の触媒１．８ｇを混合して浄化材
とし、反応管内にセットした。次に、表２に示す組成の
ガス（一酸化炭素、一酸化窒素、酸素、プロピレン、及
び窒素）を毎分４．４リットル（標準状態）の流量で流
して（全体の見かけ空間速度約１５，０００ｈ-1、銀系
触媒、金系触媒とPt系触媒の接触時間はそれぞれ０．０
５、０．０２５、０．０２５秒・ｇ／ml）、反応管内の
排ガス温度を２００〜７００℃の範囲に保ち、プロピレ
ンと窒素酸化物とを反応させた。A silver-based first catalyst (3.7 g), a gold-based second catalyst (1.8 g) and a platinum-based third catalyst (1.8 g) were mixed to prepare a purification material, which was set in the reaction tube. Next, a gas having the composition shown in Table 2 (carbon monoxide, nitric oxide, oxygen, propylene, and nitrogen) was caused to flow at a flow rate of 4.4 liters per minute (standard state) (total apparent space velocity of about 15 2,000h -1 , contact time of silver-based catalyst, gold-based catalyst and Pt-based catalyst is 0.0
5, 0.025, 0.025 sec.g / ml), the exhaust gas temperature in the reaction tube was kept in the range of 200 to 700 ° C., and propylene was reacted with nitrogen oxides.
【００７３】反応管通過後のガスの窒素酸化物の濃度を
化学発光式窒素酸化物分析計により測定し、窒素酸化物
の除去率を求めた。結果を図４に示す。The nitrogen oxide concentration of the gas after passing through the reaction tube was measured by a chemiluminescence type nitrogen oxide analyzer to determine the nitrogen oxide removal rate. The results are shown in Fig. 4.
【００７４】実施例１３ 実施例１２で作成した浄化材を用いて、表２に示すガス
組成の内プロピレンに換えてエタノール（添加量は窒素
酸化物の質量の３倍）を用いて、実施例１２と同様な方
法で評価した。実験結果を図４に示す。 Example 13 Using the purification material prepared in Example 12, ethanol was used instead of propylene in the gas composition shown in Table 2 (the addition amount was 3 times the mass of nitrogen oxide). Evaluation was made in the same manner as 12. The experimental results are shown in FIG.
【００７５】実施例１４ 実施例１２と同様な方法で、市販のコージェライト製ハ
ニカム状成形体（直径３０mm、長さ約１２．６mm、４０
０セル／平方インチ）に、硝酸銀水溶液を用いて粉末状
γ−アルミナ（比表面積２００ｍ2 ／ｇ）に塩化銀が２
重量％（銀元素換算値）担持されている触媒約１ｇをコ
ートし、乾燥後、６００℃まで段階的に焼成し、銀系浄
化材を調製した。また、同様のハニカム状成形体（長さ
６mm）に、粉末状γ−アルミナにPtが１重量％担持され
ている触媒０．４ｇをコートし、乾燥後、７００℃まで
焼成し、白金系浄化材を調製した。さらに、同様のハニ
カム状成形体（長さ６mm）に塩化金酸水溶液を用いて、
粉末状チタニア（比表面積５０ｍ2 ／ｇ）に金が１重量
％担持されている触媒０．４ｇをコートし、乾燥後、７
００℃まで焼成し、金系浄化材を調製した。排ガスの流
入側から、銀系浄化材、金系浄化材、白金系浄化材の順
に組み合わせて、反応管内にセットし、表２と同組成の
ガスで実施例１２と同じ方法で評価した（全体の見かけ
空間速度約１５，０００ｈ-1）。実験結果を図４に示
す。 Example 14 In the same manner as in Example 12, a commercially available cordierite honeycomb molded body (diameter 30 mm, length about 12.6 mm, 40 mm
0 cells / square inch) and 2 parts of silver chloride were added to powdery γ-alumina (specific surface area 200 m 2 / g) using an aqueous solution of silver nitrate.
About 1 g of the catalyst supported by weight% (converted to silver element) was coated, dried, and then calcined stepwise to 600 ° C. to prepare a silver-based purification material. A similar honeycomb shaped body (length 6 mm) was coated with 0.4 g of a catalyst in which 1 wt% of Pt was supported on powdery γ-alumina, dried, and fired to 700 ° C to purify the platinum system. The material was prepared. Furthermore, using a similar honeycomb shaped body (length 6 mm) with an aqueous chloroauric acid solution,
The powdery titania (specific surface area 50 m 2 / g) was coated with 0.4 g of a catalyst supporting 1% by weight of gold, and after drying, 7
The gold-based purification material was prepared by firing to 00 ° C. From the inflow side of the exhaust gas, a silver-based purification material, a gold-based purification material, and a platinum-based purification material were combined in this order, set in a reaction tube, and evaluated with the same composition as in Table 2 in the same manner as in Example 12 (total). Apparent space velocity of about 15,000 h -1 ). The experimental results are shown in FIG.
【００７６】実施例１５ 実施例１４で作成した浄化材を用いて、表２に示すガス
組成の内プロピレンに換えて軽油（添加量は窒素酸化物
の質量の３倍）を用いて、実施例１４と同様な方法で評
価した。実験結果を図４に示す。 Example 15 Using the purification material prepared in Example 14, light oil (addition amount was 3 times the mass of nitrogen oxide) was used instead of propylene in the gas composition shown in Table 2. Evaluation was performed in the same manner as in 14. The experimental results are shown in FIG.
【００７７】実施例１６ 実施例１４で作成した浄化材を用いて、表２に示すガス
組成の内プロピレンに換えてエタノール（添加量は窒素
酸化物の質量の３倍）を用いて、実施例１４と同様な方
法で評価した。実験結果を図４に示す。 Example 16 Using the purification material prepared in Example 14, ethanol was used instead of propylene in the gas composition shown in Table 2 (the addition amount was 3 times the mass of nitrogen oxide). Evaluation was performed in the same manner as in 14. The experimental results are shown in FIG.
【００７８】比較例４ 実施例１２と同様な方法で、γ−アルミナペレット１０
ｇに塩化銀を５重量％（銀元素換算値）担持してなる浄
化材３．６ｇを反応管にセットし、表２に示す組成のガ
スで評価した。実験結果を図４に示す。 Comparative Example 4 In the same manner as in Example 12, γ-alumina pellets 10
3.6 g of a purification material in which 5% by weight of silver chloride (converted to a silver element) was loaded in g was set in a reaction tube, and the gas having the composition shown in Table 2 was used for evaluation. The experimental results are shown in FIG.
【００７９】以上からわかるように、実施例１２〜１６
においては、広い排ガス温度範囲で窒素酸化物の良好な
除去がみられた。一方、比較例４においては、窒素酸化
物除去の温度範囲が狭かった。As can be seen from the above, Examples 12 to 16
, The nitrogen oxides were removed well in a wide exhaust gas temperature range. On the other hand, in Comparative Example 4, the temperature range for removing nitrogen oxides was narrow.
【００８０】[0080]
【発明の効果】以上詳述したように、本発明の排ガス浄
化材を用いれば、広い温度領域において過剰の酸素を含
む排ガス中の窒素酸化物を効率良く除去することができ
る。本発明の排ガス浄化材及び浄化方法は、各種燃焼
機、自動車等の排ガス浄化に広く利用することができ
る。As described above in detail, by using the exhaust gas purifying material of the present invention, nitrogen oxides in exhaust gas containing excess oxygen can be efficiently removed in a wide temperature range. INDUSTRIAL APPLICABILITY The exhaust gas purifying material and the purifying method of the present invention can be widely used for purifying exhaust gas of various combustors, automobiles and the like.
【図１】実施例１〜３及び比較例１における排ガス温度
と排ガス中の窒素酸化物の除去率の関係を示すグラフで
ある。FIG. 1 is a graph showing the relationship between the exhaust gas temperature and the removal rate of nitrogen oxides in the exhaust gas in Examples 1 to 3 and Comparative Example 1.
【図２】実施例４〜６及び比較例２における排ガス温度
と排ガス中の窒素酸化物の除去率の関係を示すグラフで
ある。FIG. 2 is a graph showing the relationship between exhaust gas temperature and nitrogen oxide removal rate in exhaust gas in Examples 4 to 6 and Comparative Example 2.
【図３】実施例７〜１１及び比較例３における排ガス温
度と排ガス中の窒素酸化物の除去率の関係を示すグラフ
である。FIG. 3 is a graph showing the relationship between the exhaust gas temperature and the removal rate of nitrogen oxides in the exhaust gas in Examples 7 to 11 and Comparative Example 3.
【図４】実施例１２〜１６及び比較例４における排ガス
温度と排ガス中の窒素酸化物の除去率の関係を示すグラ
フである。FIG. 4 is a graph showing the relationship between exhaust gas temperature and nitrogen oxide removal rate in exhaust gas in Examples 12 to 16 and Comparative Example 4.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｂ０１Ｊ 23/66 ＺＡＢ Ａ 8017−4Ｇ 35/02 ＺＡＢ Ｐ 8017−4Ｇ Ｂ０１Ｄ 53/36 １０２ Ｈ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Office reference number FI Technical display location B01J 23/66 ZAB A 8017-4G 35/02 ZAB P 8017-4G B01D 53/36 102 H
Claims (9)
する理論反応量より多い酸素とを含む燃焼排ガスから窒
素酸化物を還元除去する排ガス浄化材において、排ガス
流入側に第一の触媒を有し、排ガス流出側に第二の触媒
を有し、前記第一の触媒が多孔質の無機酸化物に活性種
である銀及び／又は銀化合物、又はそれらの混合物０．
２〜１５重量％（銀元素換算値）を担持してなり、前記
第二の触媒が多孔質の無機酸化物に活性種である金０．
０２〜５重量％を担持してなり、外部から前記排ガス中
に炭化水素及び／又は含酸素有機化合物を還元剤として
添加し、１５０〜６５０℃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. An exhaust gas purification material for reducing and 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 a first catalyst is provided on the exhaust gas inflow side. However, it has a second catalyst on the exhaust gas outflow side, and the first catalyst is silver and / or a silver compound which is an active species for the porous inorganic oxide, or a mixture thereof.
2 to 15% by weight (converted to a silver element) is supported, and the second catalyst is a porous inorganic oxide in which gold, which is an active species, is added.
Carrying 02 to 5% by weight, externally adding a hydrocarbon and / or an oxygen-containing organic compound to the exhaust gas as a reducing agent to reduce nitrogen oxides in the exhaust gas at 150 to 650 ° C. Exhaust gas purification material characterized by
する理論反応量より多い酸素とを含む燃焼排ガスから窒
素酸化物を還元除去する排ガス浄化材において、第一の
触媒と第二の触媒を混合して用い、前記第一の触媒が多
孔質の無機酸化物に活性種である銀及び／又は銀化合
物、又はそれらの混合物０．２〜１５重量％（銀元素換
算値）を担持してなり、前記第二の触媒が多孔質の無機
酸化物に活性種である金０．０２〜５重量％を担持して
なり、外部から前記排ガス中に炭化水素及び／又は含酸
素有機化合物を還元剤として添加し、１５０〜６５０℃
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。2. An exhaust gas purification material for reducing and 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 a first catalyst and a second catalyst are used. Used as a mixture, the first catalyst carries 0.2 to 15% by weight (silver element conversion value) of silver and / or a silver compound which is an active species or a mixture thereof in a porous inorganic oxide. The second catalyst comprises a porous inorganic oxide carrying 0.02 to 5% by weight of gold, which is an active species, and externally reduces hydrocarbons and / or oxygen-containing organic compounds in the exhaust gas. 150 to 650 ℃
The exhaust gas purifying material is characterized by reducing nitrogen oxides in the exhaust gas.
おいて、前記多孔質無機酸化物が、第一の触媒ではγ−
アルミナ又はアルミナ系複合酸化物で、第二の触媒では
アルミナ、チタニア、酸化亜鉛、酸化マグネシウムのい
ずれか又はその内の二つ以上からなる複合酸化物である
ことを特徴とする排ガス浄化材。3. The exhaust gas purifying material according to claim 1, wherein the porous inorganic oxide is γ-in the first catalyst.
An exhaust gas purifying material, characterized in that it is an alumina or an alumina-based composite oxide, and the second catalyst is any one of alumina, titania, zinc oxide, magnesium oxide, or a composite oxide composed of two or more thereof.
する理論反応量より多い酸素とを含む燃焼排ガスから窒
素酸化物を還元除去する排ガス浄化材において、排ガス
流入側から流出側に順に第一、第二、第三の触媒を有
し、前記第一の触媒が多孔質の無機酸化物に活性種であ
る銀及び／又は銀化合物、又はそれらの混合物０．２〜
１５重量％（銀元素換算値）を担持してなり、前記第二
の触媒が多孔質の無機酸化物に活性種である金０．０２
〜５重量％を担持してなり、前記第三の触媒が多孔質の
無機酸化物に活性種であるPt、Pd、Ru、Rh、Irからなる
群より選ばれた少なくとも１種の元素０．０２〜５重量
％を担持してなり、外部から前記排ガス中に炭化水素及
び／又は含酸素有機化合物を還元剤として添加し、１５
０〜６５０℃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。4. An exhaust gas purification material for reducing and 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. , A second and a third catalyst, wherein the first catalyst is an active species for a porous inorganic oxide, and / or a silver compound, or a mixture thereof.
15% by weight (silver element conversion value) is supported, and the second catalyst is 0.02 gold which is an active species in the porous inorganic oxide.
.About.5% by weight, and the third catalyst contains at least one element selected from the group consisting of Pt, Pd, Ru, Rh, and Ir, which is an active species, in a porous inorganic oxide. 02 to 5 wt% is supported, and a hydrocarbon and / or an oxygen-containing organic compound is added to the exhaust gas as a reducing agent from the outside.
An exhaust gas purifying material, which reduces nitrogen oxides in the exhaust gas at 0 to 650 ° C.
する理論反応量より多い酸素とを含む燃焼排ガスから窒
素酸化物を還元除去する排ガス浄化材において、第一の
触媒、第二の触媒及び第三の触媒を混合して用い、前記
第一の触媒が多孔質の無機酸化物に活性種である銀及び
／又は銀化合物、又はそれらの混合物０．２〜１５重量
％（銀元素換算値）を担持してなり、前記第二の触媒が
多孔質の無機酸化物に活性種である金０．０２〜５重量
％を担持してなり、前記第三の触媒が多孔質の無機酸化
物に活性種であるPt、Pd、Ru、Rh、Irからなる群より選
ばれた少なくとも１種の元素０．０２〜５重量％を担持
してなり、外部から前記排ガス中に炭化水素及び／又は
含酸素有機化合物を還元剤として添加し、１５０〜６５
０℃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。5. An exhaust gas purifying material for reducing and 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 a first catalyst, a second catalyst and The third catalyst is mixed and used, and the first catalyst is silver and / or a silver compound which is an active species in a porous inorganic oxide, or a mixture thereof 0.2 to 15% by weight (silver element conversion value) ), The second catalyst carries 0.02 to 5% by weight of gold, which is an active species, on a porous inorganic oxide, and the third catalyst comprises a porous inorganic oxide. Is loaded with 0.02 to 5% by weight of at least one element selected from the group consisting of Pt, Pd, Ru, Rh, and Ir which are active species, and hydrocarbons and / or externally contained in the exhaust gas. Add an oxygen-containing organic compound as a reducing agent,
An exhaust gas purification material, which reduces nitrogen oxides in the exhaust gas at 0 ° C.
おいて、前記多孔質無機酸化物が、第一の触媒ではγ−
アルミナ又はアルミナ系複合酸化物で、第二の触媒では
アルミナ、チタニア、酸化亜鉛、酸化マグネシウムのい
ずれか又はその内の二つ以上からなる複合酸化物で、第
三の触媒ではアルミナ、チタニア、ジルコニアのいずれ
か又はその内の二つ以上の複合酸化物であることを特徴
とする排ガス浄化材。6. The exhaust gas purifying material according to claim 4, wherein the porous inorganic oxide is γ-in the first catalyst.
Alumina or an alumina-based composite oxide, the second catalyst is any one of alumina, titania, zinc oxide, magnesium oxide or a composite oxide composed of two or more thereof, and the third catalyst is alumina, titania, zirconia. 2. An exhaust gas purification material, characterized in that it is any one of the above or two or more complex oxides therein.
浄化材において、前記浄化材は前記各触媒をセラミック
ス製又は金属製の３次元構造体の表面にコートしてなる
ことを特徴とする排ガス浄化材。7. The exhaust gas purifying material according to claim 1, wherein the purifying material is formed by coating the surface of a ceramic or metal three-dimensional structure with each of the catalysts. Exhaust gas purification material.
浄化材において、前記各触媒の多孔質無機酸化物はそれ
ぞれペレット状又は顆粒状であることを特徴とする排ガ
ス浄化材。8. The exhaust gas purifying material according to any one of claims 1 to 6, wherein the porous inorganic oxide of each catalyst is in the form of pellets or granules.
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排ガス浄化方法において、請求項１
〜８のいすれかに記載の排ガス浄化材を用い、前記排ガ
ス浄化材を排ガス導管の途中に設置し、前記浄化材の上
流側で炭化水素及び／又は含酸素有機化合物を添加した
排ガスを、１５０〜６５０℃において前記浄化材に接触
させ、もって前記排ガス中の有機化合物との反応により
前記窒素酸化物を除去することを特徴とする排ガス浄化
方法。9. An exhaust gas purification method 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.
~ 8 using the exhaust gas purification material according to any one of, the exhaust gas purification material is installed in the middle of the exhaust gas conduit, the exhaust gas to which the hydrocarbon and / or oxygen-containing organic compound is added upstream of the purification material, An exhaust gas purification method, which comprises contacting the purification material at 150 to 650 ° C., thereby removing the nitrogen oxides by a reaction with an organic compound in the exhaust gas.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6186606A JPH0780306A (en) | 1993-07-20 | 1994-07-15 | Waste gas purifying material and waste gas purifying method |
| US08/340,329 US5658542A (en) | 1994-07-15 | 1994-11-14 | Exhaust gas cleaner and method for cleaning same |
| EP95301815A EP0692300B1 (en) | 1994-07-15 | 1995-03-17 | Exhaust gas cleaner and method for cleaning same |
| DE69503986T DE69503986T2 (en) | 1994-07-15 | 1995-03-17 | Exhaust gas purifier and method for cleaning it |
| US08/531,904 US5670444A (en) | 1994-07-15 | 1995-09-21 | Exhaust gas cleaner and method for cleaning same |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20039193 | 1993-07-20 | ||
| JP5-200391 | 1993-07-20 | ||
| JP6186606A JPH0780306A (en) | 1993-07-20 | 1994-07-15 | Waste gas purifying material and waste gas purifying method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0780306A true JPH0780306A (en) | 1995-03-28 |
Family
ID=26503868
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6186606A Pending JPH0780306A (en) | 1993-07-20 | 1994-07-15 | Waste gas purifying material and waste gas purifying method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0780306A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010284648A (en) * | 2002-11-27 | 2010-12-24 | Volvo Technology Corp | Catalyst unit for reduction of nox compound |
-
1994
- 1994-07-15 JP JP6186606A patent/JPH0780306A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010284648A (en) * | 2002-11-27 | 2010-12-24 | Volvo Technology Corp | Catalyst unit for reduction of nox compound |
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