JPH06238166A - Cleaning material for exhaust gas and cleaning method for exhaust gas - Google Patents
Cleaning material for exhaust gas and cleaning method for exhaust gasInfo
- Publication number
- JPH06238166A JPH06238166A JP5048613A JP4861393A JPH06238166A JP H06238166 A JPH06238166 A JP H06238166A JP 5048613 A JP5048613 A JP 5048613A JP 4861393 A JP4861393 A JP 4861393A JP H06238166 A JPH06238166 A JP H06238166A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- catalyst
- oxide
- silver
- weight
- 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
- 238000000034 method Methods 0.000 title claims description 30
- 239000011538 cleaning material Substances 0.000 title abstract 3
- 238000004140 cleaning Methods 0.000 title 1
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims abstract description 224
- 239000007789 gas Substances 0.000 claims abstract description 95
- 239000003054 catalyst Substances 0.000 claims abstract description 91
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 33
- 239000001301 oxygen Substances 0.000 claims abstract description 33
- 229910052709 silver Inorganic materials 0.000 claims abstract description 33
- 239000004332 silver Substances 0.000 claims abstract description 33
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 32
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 claims abstract description 23
- 238000002485 combustion reaction Methods 0.000 claims abstract description 19
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 14
- 229910052802 copper Inorganic materials 0.000 claims abstract description 14
- 239000010949 copper Substances 0.000 claims abstract description 14
- 229910001923 silver oxide Inorganic materials 0.000 claims abstract description 13
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 claims abstract description 7
- 239000005751 Copper oxide Substances 0.000 claims abstract description 7
- 229910000431 copper oxide Inorganic materials 0.000 claims abstract description 7
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 6
- 229910052741 iridium Inorganic materials 0.000 claims abstract description 5
- 229910052703 rhodium Inorganic materials 0.000 claims abstract description 5
- 229910052707 ruthenium Inorganic materials 0.000 claims abstract description 5
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 4
- 239000000463 material Substances 0.000 claims description 69
- 229930195733 hydrocarbon Natural products 0.000 claims description 43
- 150000002430 hydrocarbons Chemical class 0.000 claims description 43
- 238000000746 purification Methods 0.000 claims description 41
- 229910052809 inorganic oxide Inorganic materials 0.000 claims description 33
- 238000006243 chemical reaction Methods 0.000 claims description 30
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 27
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 27
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical group [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 23
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 20
- 239000000758 substrate Substances 0.000 claims description 20
- 239000004215 Carbon black (E152) Substances 0.000 claims description 17
- 150000002894 organic compounds Chemical class 0.000 claims description 12
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 11
- 229910052751 metal Inorganic materials 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 9
- 239000002131 composite material Substances 0.000 claims description 8
- 230000001590 oxidative effect Effects 0.000 claims description 6
- 230000003647 oxidation Effects 0.000 claims description 5
- 238000007254 oxidation reaction Methods 0.000 claims description 5
- 238000011144 upstream manufacturing Methods 0.000 claims description 4
- 239000000919 ceramic Substances 0.000 claims description 3
- 239000008188 pellet Substances 0.000 claims description 3
- 239000008187 granular material Substances 0.000 claims 1
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 abstract description 12
- 238000000151 deposition Methods 0.000 abstract 3
- OTCVAHKKMMUFAY-UHFFFAOYSA-N oxosilver Chemical class [Ag]=O OTCVAHKKMMUFAY-UHFFFAOYSA-N 0.000 abstract 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 29
- 239000003638 chemical reducing agent Substances 0.000 description 11
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 10
- 229910052761 rare earth metal Inorganic materials 0.000 description 8
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 8
- 239000007864 aqueous solution Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- -1 Oxygen organic compounds Chemical class 0.000 description 6
- 238000005470 impregnation Methods 0.000 description 6
- 229910052783 alkali metal Inorganic materials 0.000 description 5
- 229910021529 ammonia Inorganic materials 0.000 description 5
- 238000010304 firing Methods 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 150000001340 alkali metals Chemical class 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 4
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 4
- 239000000377 silicon dioxide Substances 0.000 description 4
- 229910001961 silver nitrate Inorganic materials 0.000 description 4
- 238000003980 solgel method Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000010531 catalytic reduction reaction Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 150000002431 hydrogen Chemical class 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 238000006722 reduction reaction 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
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 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
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- 150000001335 aliphatic alkanes Chemical class 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 2
- 229910052878 cordierite Inorganic materials 0.000 description 2
- 230000007423 decrease Effects 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
- 239000000446 fuel Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 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
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 229910001122 Mischmetal Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 239000011865 Pt-based catalyst Substances 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- NEIHULKJZQTQKJ-UHFFFAOYSA-N [Cu].[Ag] Chemical compound [Cu].[Ag] NEIHULKJZQTQKJ-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 150000001345 alkine derivatives Chemical class 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 229910052792 caesium Inorganic materials 0.000 description 1
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 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
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- 238000011049 filling Methods 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
- 239000012535 impurity 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
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000000243 solution Substances 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
- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (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還元除去
するとともに、一酸化炭素及び炭化水素を酸化除去する
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。TECHNICAL FIELD The present invention relates to exhaust gas purification capable of effectively reducing and removing nitrogen oxides and oxidizing and removing carbon monoxide and hydrocarbons from combustion exhaust gas containing nitrogen oxides and excess oxygen. The present invention relates to a material and a purification method using the material.
【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 emitted 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、効果的
な窒素酸化物の除去が狭い温度領域でしか得られず、ま
た、水分を含むような排ガスでは、窒素酸化物の除去率
が著しく低下する。つまり、１０％程度の水分を含み、
運転条件によって温度変化の大きい車等からの排ガスに
対して、窒素酸化物の効果的除去は困難である。However, with these methods, effective removal of nitrogen oxides can be obtained only in a narrow temperature range, and in exhaust gas containing water, the removal rate of nitrogen oxides is significantly reduced. In other words, it contains about 10% of water,
It is difficult to effectively remove nitrogen oxides from exhaust gas from a vehicle or the like whose temperature greatly changes depending on operating conditions.
【０００９】したがって、本発明の目的は、固定燃焼装
置および酸素過剰条件で燃焼するガソリンエンジン、デ
ィーゼルエンジン等からの燃焼排ガスのように、窒素酸
化物や、一酸化炭素、水素、炭化水素等の未燃焼分に対
する理論反応量以上の酸素を含有する燃焼排ガスから、
効率良く窒素酸化物を還元除去するとともに、一酸化炭
素及び炭化水素を酸化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 reducing and removing nitrogen oxides and oxidizing and removing carbon monoxide and hydrocarbons.
【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特定量の銀
成分を担持してなる第一の触媒と、銀成分と銅成分を担
持してなる第二の触媒と、Pt等の成分を担持してなる第
三の触媒とを分離して形成される排ガス浄化材を用い、
排ガス中に炭化水素又は含酸素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
効果的に除去するとともに、一酸化炭素及び炭化水素も
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 inventors have found that a first catalyst comprising a porous inorganic oxide carrying a specific amount of a silver component, a silver component and copper. Using an exhaust gas purifying material formed by separating a second catalyst supporting a component and a third catalyst supporting a component such as Pt,
If hydrocarbon or oxygen-containing organic compound is added to the exhaust gas and the exhaust gas is brought into contact with the above catalyst at a specific temperature, 10%
The present inventors have completed the present invention by discovering that even in exhaust gas containing water, it is possible to effectively remove nitrogen oxides in a wide temperature range and also remove carbon monoxide and hydrocarbons.
【００１１】すなわち、窒素酸化物と、共存する未燃焼
成分に対する理論反応量より多い酸素とを含む燃焼排ガ
スから窒素酸化物を還元除去するとともに、一酸化炭素
及び炭化水素を酸化除去する本発明の排ガス浄化材は、
浄化材の排ガス流入側から流出側に順に第一〜第三の触
媒を有しており、前記第一の触媒が多孔質の無機酸化物
に活性種として銀又は銀酸化物０．２〜１５重量％（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として銀又は銀酸化物０．２〜１５
重量％（元素換算値）と銅又は銅酸化物２重量％以下
（元素換算値）とを担持してなり、前記第三の触媒が多
孔質の無機酸化物に活性種として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２重量％以
下を担持してなることを特徴とする。That is, nitrogen oxides are reduced and removed from combustion exhaust gas containing nitrogen oxides and oxygen in a larger amount than the theoretical reaction amount for coexisting unburned components, and carbon monoxide and hydrocarbons are removed by oxidation. Exhaust gas purification material
The purification material has first to third catalysts in this order from the exhaust gas inflow side to the outflow side, and the first catalyst is a porous inorganic oxide containing silver or silver oxide 0.2 to 15 as an active species. % Of the element (converted value) is carried, and the second catalyst contains 0.2 to 15 silver or silver oxide as an active species in the porous inorganic oxide.
Wt% (elemental conversion value) and copper or copper oxide 2 wt% or less (elemental conversion value) are supported, and the third catalyst is a porous inorganic oxide containing Pt, Pd, Ru as active species. , Rh, Ir at least one element selected from the group consisting of 2% by weight or less.
【００１２】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
ら窒素酸化物を還元除去するとともに、一酸化炭素及び
炭化水素を酸化除去する本発明の排ガス浄化方法は、上
記排ガス浄化材を排ガス導管の途中に設置し、前記浄化
材の上流側で炭化水素又は含酸素有機化合物を添加した
排ガスを、２００〜６００℃において前記浄化材に接触
させ、もって前記排ガス中の炭化水素又は含酸素有機化
合物との反応により前記窒素酸化物、一酸化炭素及び炭
化水素を除去することを特徴とする。In addition, nitrogen oxides are reduced and removed from combustion exhaust gas containing nitrogen oxides and oxygen in a larger amount than the theoretical reaction amount for coexisting unburned components, and carbon monoxide and hydrocarbons are removed by oxidation. The exhaust gas purification method, the exhaust gas purification material is installed in the middle of the exhaust gas conduit, the exhaust gas to which a hydrocarbon or an oxygen-containing organic compound is added on the upstream side of the purification material, contact the purification material at 200 ~ 600 ℃, Therefore, the nitrogen oxides, carbon monoxide and hydrocarbons are removed by reaction with the hydrocarbons or oxygen-containing organic compounds in the exhaust gas.
【００１３】以下、本発明を詳細に説明する。本発明で
は、排ガス流入側に、多孔質の無機酸化物に活性種であ
る銀又は銀酸化物０．２〜１５重量％（元素換算値）を
担持してなる第一の触媒を形成し、流出側に多孔質の無
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２重量％以下を担持
してなる第三の触媒を形成し、第一の触媒と第三の触媒
の間に、多孔質の無機酸化物に活性種である銀又は銀酸
化物０．２〜１５重量％（元素換算値）と銅又は銅酸化
物２重量％以下（元素換算値）とを担持してなる第二の
触媒を形成してなる排ガス浄化材を排ガス導管中に設置
し、浄化材の設置位置より上流側で排ガス中に炭化水素
又は含酸素有機化合物を添加して排ガスをこの浄化材に
接触させ、炭化水素、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し、残留または未反応
の一酸化炭素および炭化水素を酸化除去する。The present invention will be described in detail below. In the present invention, on the exhaust gas inflow side, a first catalyst is formed by supporting 0.2 to 15% by weight (element conversion value) of silver or silver oxide, which is an active species, on a porous inorganic oxide, A third catalyst is formed on the outflow side, in which 2% by weight or less of at least one element selected from the group consisting of Pt, Pd, Ru, Rh, and Ir that is an active species is supported by a porous inorganic oxide. Then, between the first catalyst and the third catalyst, 0.2 to 15% by weight (element conversion value) of silver or silver oxide which is an active species in the porous inorganic oxide and copper or copper oxide 2 An exhaust gas purifying material formed by forming a second catalyst having a content of less than or equal to wt% (elemental conversion value) is installed in the exhaust gas conduit, and hydrocarbons or impurities are contained in the exhaust gas upstream from the installation position of the purifying material. Oxygen organic compounds are added to bring the exhaust gas into contact with this purification material, and hydrocarbons and oxygen-containing organic compounds are used as reducing agents to reduce the concentration of nitrogen in the exhaust gas. Elementary oxides are reduced and removed, and residual or unreacted carbon monoxide and hydrocarbons are removed by oxidation.
【００１４】本発明の排ガス浄化材の第一の好ましい形
態は、粉末状の多孔質無機酸化物に触媒活性種を担持し
てなる触媒を浄化材基体にコートしてなる浄化材であ
る。浄化材の基体を形成するセラミックス材料として
は、γ−アルミナ及びその酸化物（γ−アルミナ−チタ
ニア、γ−アルミナ−シリカ、γ−アルミナ−ジルコニ
ア等）、ジルコニア、チタニア−ジルコニアなどの多孔
質で表面積の大きい耐熱性のものが挙げられる。高耐熱
性が要求される場合、コージェライト、ムライト、アル
ミナ及びその複合物等を用いるのが好ましい。また、排
ガス浄化材の基体に公知の金属材料を用いることもでき
る。A first preferred form of the exhaust gas purifying material of the present invention is a purifying material in which a purifying material substrate is coated with a catalyst comprising a powdery porous inorganic oxide carrying a catalytically active species. As the ceramic material forming the substrate of the purification material, γ-alumina and its 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.
【００１５】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、
中間部分、及び出口部分等、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、繊維状耐火物からなる三次元網目構造
型、あるいは顆粒状、ペレット状等が挙げられる。The shape and size of the substrate of the exhaust gas purifying material is
Various changes can be made according to the purpose. Practically, the entrance part,
It is preferably composed of two or more parts such as an intermediate part and an outlet part. Examples of the structure include a honeycomb structure type, a foam type, a three-dimensional network structure type made of fibrous refractory, a granular form, a pellet form and the like.
【００１６】本発明の排ガス浄化材の第二の好ましい形
態は、ペレット状又は顆粒状粉末状の多孔質無機酸化物
に触媒活性種を担持してなる触媒を充填してなる浄化材
である。A second preferred form of the exhaust gas purifying material of the present invention is a purifying material obtained by filling a catalyst in which a catalytically active species is supported on a pellet-like or granular powder-like porous inorganic oxide.
【００１７】本発明の浄化材には以下の三つの触媒が形
成されている。 （１）第一の触媒 第一の触媒は、多孔質無機酸化物に銀成分を担持してな
り、排ガスの流入側に形成され、主に高い温度領域での
窒素酸化物除去に作用する。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、添加した炭化水素、含酸素有機化合物
及び／又は排ガス中の残留炭化水素と排ガス中の窒素酸
化物との反応が効率良く起こる。The following three catalysts are formed in the purifying material of the present invention. (1) First catalyst The first catalyst comprises a porous inorganic oxide carrying a silver component, is formed on the inflow side of exhaust gas, and mainly acts to remove nitrogen oxides in a high temperature region. 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. By using γ-alumina or an alumina-based composite oxide, the reaction between the added hydrocarbon, the oxygen-containing organic compound and / or the residual hydrocarbon in the exhaust gas and the nitrogen oxide in the exhaust gas occurs efficiently.
【００１８】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.
【００１９】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％（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。好ましい銀成分の担持量は０．５〜１
０重量％である。なお、銀成分は、排ガスの温度領域で
は金属又は酸化物の状態にあり、相互に容易に変換し得
る。The amount of the silver component supported on the above-mentioned inorganic oxide such as γ-alumina as the active species is 10
0.2 to 15% by weight (elemental conversion value) relative to 0% by weight. If it is less than 0.2% by weight, the removal rate of nitrogen oxides is lowered. On the other hand, when silver is loaded in an amount of more than 15% by weight, the hydrocarbon itself is easily burned, and the nitrogen oxide removal rate is rather lowered. The preferred amount of silver component supported is 0.5 to 1.
It is 0% by weight. The silver component is in the state of metal or oxide in the temperature range of exhaust gas and can be easily converted into each other.
【００２０】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、沈澱法、ゾル−ゲル法
等を用いることができる。含浸法を用いる際、硝酸銀水
溶液等の銀成分を有する溶液に多孔質無機酸化物を浸漬
し、７０℃程度で乾燥後、１００〜６００℃で段階的に
昇温して焼成するのが好ましい。この焼成は酸素雰囲気
下、窒素雰囲気下、又は水素ガス流下で行うことができ
る。窒素雰囲気下、又は水素ガス流下で焼成した場合、
最後に酸化処理するのが好ましく、少量の窒素酸化物が
存在すると、さらに効果的である。As a method for supporting a silver component on an inorganic oxide such as alumina, a known impregnation method, precipitation method, sol-gel method or the like can be used. When the impregnation method is used, it is preferable to immerse the porous inorganic oxide in a solution having a silver component such as an aqueous solution of silver nitrate, dry it at about 70 ° C., and then gradually raise the temperature at 100 to 600 ° C. to bake. This firing can be performed in an oxygen atmosphere, a nitrogen atmosphere, or a hydrogen gas flow. When firing in a nitrogen atmosphere or under a flow of hydrogen gas,
A final oxidative treatment is preferred, and the presence of small amounts of nitrogen oxides is more effective.
【００２１】なお、浄化材の形態を上述した第一の好ま
しい形態とする場合、浄化材基体上に設ける第一の触媒
の厚さは、一般に、基体材と、この触媒との熱膨張特性
の違いから制限される場合が多い。浄化材基体上に設け
る触媒の厚さを２００μｍ以下とするのがよい。このよ
うな厚さとすれば、使用中に熱衝撃等で浄化材が破損す
ることを防ぐことができる。浄化材基体の表面に触媒を
形成する方法は公知のウォシュコート法、ゾル−ゲル法
等によって行われる。When the form of the purifying material is the above-mentioned first preferred form, the thickness of the first catalyst provided on the purifying material base is generally determined by the thermal expansion characteristics of the base material and this catalyst. Often limited by differences. 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 the purification material from being damaged by thermal shock during use. The catalyst is formed on the surface of the purification material substrate by a known washcoat method, sol-gel method, or the like.
【００２２】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５〜７０重量％とするのが好ま
しい。触媒の量が５重量％未満では良好なNOx の除去が
行えない。一方、触媒の量が７０重量％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１０〜７０重量％とする。The amount of the first catalyst provided on the surface of the purification material substrate is preferably 5 to 70% by weight of the purification material substrate. If the amount of the catalyst is less than 5% by weight, good NOx cannot be removed. On the other hand, when the amount of the catalyst exceeds 70% by weight, 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 10 to 70% by weight of the purification material substrate.
【００２３】（２）第二の触媒 第二の触媒は、多孔質無機酸化物に銀成分と銅成分を担
持してなり、排ガスの流出側に面する除去材基体に形成
され、低い温度領域での窒素酸化物の除去に作用する。
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３０ｍ2 ／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 silver component and a copper component and is formed on a removing material substrate facing the outflow side of exhaust gas. It acts on the removal of nitrogen oxides.
As the porous inorganic oxide, γ-alumina and its oxide (γ-alumina-titania, γ-alumina-silica,
γ-alumina-zirconia, etc.), zirconia, titania-zirconia, and other heat-resistant ceramics having a large surface area. Preferably, γ-alumina, titania, zirconia and a composite oxide containing them are used. Similar to the first catalyst, the specific surface area of the porous inorganic oxide is preferably 30 m 2 / g or more.
【００２４】上記の第二触媒の活性種としては、（ａ）
銀又は銀酸化物と銅又は銅酸化物を混合し、あるいはさ
らに、（ｂ）アルカリ金属元素と希土類元素とからなる
群より選ばれた少なくとも１種の元素とを混合して用い
る。アルカリ金属元素としては、特にセシウム、ナトリ
ウム及びカリウムを用いるのが好ましい。また、希土類
元素としては、ランタン、セリウム、ネオジウムを用い
るのが好ましいが、希土類の混合物であるミッシュメタ
ルを用いることもできる。The active species of the above second catalyst include (a)
Silver or silver oxide and copper or copper oxide are mixed, or further, (b) at least one element selected from the group consisting of alkali metal elements and rare earth elements is mixed and used. As the alkali metal element, it is particularly preferable to use cesium, sodium and potassium. As the rare earth element, lanthanum, cerium or neodymium is preferably used, but a misch metal which is a mixture of rare earth elements can also be used.
【００２５】多孔質無機酸化物を１００重量％として、
銀又は銀酸化物の担持量は０．２〜１５重量％（金属元
素換算値）で、銅又は銅酸化物の担持量は２重量％以下
（金属元素換算値）である。また銀成分と銅成分の合計
担持量は１７重量％以下（金属元素換算値）である。銀
又は銀酸化物の好ましい担持量が０．５重量％未満又は
１０重量％であり、銅の好ましい担持量は１．５重量％
以下とする。With the porous inorganic oxide as 100% by weight,
The amount of silver or silver oxide supported is 0.2 to 15% by weight (metal element conversion value), and the amount of copper or copper oxide supported is 2% by weight or less (metal element conversion value). The total amount of silver and copper components supported is 17% by weight or less (metal element conversion value). The preferred loading of silver or silver oxide is less than 0.5% by weight or 10% by weight, and the preferred loading of copper is 1.5% by weight.
Below.
【００２６】アルカリ金属元素と希土類元素とを併用す
る場合、合計担持量（ｂ）は２重量％以下とし、好まし
くは０．５〜１．５重量％とする。また、アルカリ金属
元素の担持量を１重量％以下とし、希土類元素の担持量
を１重量％以下とするのが好ましい。いずれの元素も１
重量％を越えると、窒素酸化物の除去率が低下する。好
ましいアルカリ金属の担持量は０．１〜０．５重量％で
ある。また好ましい希土類元素の担持量は０．１〜０．
５重量％である。When the alkali metal element and the rare earth element are used in combination, the total supported amount (b) is 2% by weight or less, preferably 0.5 to 1.5% by weight. Further, it is preferable that the supported amount of the alkali metal element is 1% by weight or less and the supported amount of the rare earth element is 1% by weight or less. All elements are 1
If it exceeds 5% by weight, the removal rate of nitrogen oxides decreases. The preferred amount of alkali metal supported is 0.1 to 0.5% by weight. The preferable amount of the rare earth element supported is 0.1 to 0.
It is 5% by weight.
【００２７】第二の触媒で無機酸化物に担持する活性種
の合計（（ａ）＋（ｂ））は、上述の多孔質の無機酸化
物を基準(100重量％) として０．１〜１９重量％とし、
好ましくは０．５〜１５重量％とする。触媒活性種の量
が前記基体に対して０．１重量％未満では触媒を担持し
た効果が顕著ではなく、NOx 低減特性は低下する。一
方、１９重量％を超す触媒担持量とすると炭化水素の酸
化燃焼のみ進み、窒素酸化物の低減特性は低下すること
になる。The total amount of active species ((a) + (b)) supported on the inorganic oxide by the second catalyst is 0.1 to 19 based on the above-mentioned porous inorganic oxide (100% by weight). % By weight,
It is preferably 0.5 to 15% by weight. If the amount of the catalytically active species is less than 0.1% by weight with respect to the substrate, the effect of supporting the catalyst is not remarkable, and the NOx reduction property deteriorates. On the other hand, if the amount of catalyst supported exceeds 19% by weight, only the oxidative combustion of hydrocarbons will proceed, and the nitrogen oxide reduction characteristics will deteriorate.
【００２８】第二の触媒における活性種の担持は、公知
の含浸法、沈殿法、ゾル−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、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、乾燥後、第一の触媒と同様の条件で焼成するこ
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、通常の除去材の使用温度条件では担持
成分は金属または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 using the impregnation method, the porous inorganic oxide should be immersed in an aqueous solution of a carbonate, nitrate, acetate, hydroxide, etc. of the catalytically active element, dried and then calcined under the same conditions as the first catalyst. Done by Although the supported component is shown as a metal element, the supported component exists in the state of metal or oxide under the normal use temperature condition of the removing material.
【００２９】なお、浄化材の形態を上述した第一の好ま
しい形態とする場合、浄化材基体上に設ける第二の触媒
の厚さを１００μｍ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
５〜７０重量％とするのが好ましい。When the form of the purification material is the above-mentioned first preferred form, the thickness of the second catalyst provided on the purification material substrate is preferably 100 μm or less. Further, the amount of the second catalyst provided on the surface of the purification material substrate is preferably 5 to 70% by weight of the purification material substrate.
【００３０】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.
【００３１】（３）第三の触媒 第三の触媒は、多孔質無機酸化物に触媒活性種を担持し
てなり、排ガスの流出側に形成され、低い温度領域にお
ける窒素酸化物の除去に作用するとともに、一酸化炭素
や炭化水素の酸化除去を行う。多孔質無機酸化物として
は、アルミナ及びその酸化物（アルミナ−チタニア、ア
ルミナ−シリカ、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, is formed on the outflow side of exhaust gas, and acts to remove nitrogen oxides in a low temperature region. In addition, carbon monoxide and hydrocarbons are removed by oxidation. Examples of the porous inorganic oxide include heat resistant ceramics having a large surface area such as alumina and oxides thereof (alumina-titania, alumina-silica, alumina-zirconia, etc.), zirconia, titania-zirconia, and the like. Preferably γ-
Alumina, titania, zirconia and a composite oxide containing them are used. Similar to the first catalyst, the specific surface area of the porous inorganic oxide is preferably 10 m 2 / g or more.
【００３２】上記の第三触媒の活性種としては、Pt、P
d、Ru、Rh、Ir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。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２重量％以下とし、好ましくは０．１〜
１．５重量％とする。触媒活性種の量が前記基体に対し
て、２重量％を超す触媒担持量とすると炭化水素の酸化
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。As the active species of the above-mentioned third catalyst, Pt, P
At least one element selected from the group consisting of d, Ru, Rh, and Ir is used. The total amount of active species supported on the inorganic oxide by the third catalyst is 2% by weight or less based on the above-mentioned porous inorganic oxide (100% by weight), preferably 0.1 to
1.5% by weight. If the amount of the catalytically active species exceeds 2% by weight with respect to the above-mentioned substrate, only the oxidative combustion of hydrocarbons will proceed and the nitrogen oxide reduction characteristics will deteriorate.
【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−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、浄化材の形態を上述した第一の好ま
しい形態とする場合、浄化材基体上に設ける第三の触媒
の厚さを１００μｍ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
５〜７０重量％とするのが好ましい。When the form of the purification material is the above-mentioned first preferred form, the thickness of the third catalyst provided on the purification material substrate is preferably 100 μm or less. The amount of the third catalyst provided on the surface of the purification material substrate is preferably 5 to 70% by weight of the purification material substrate.
【００３６】本発明においては、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、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ず、また、一酸化炭素や炭化
水素の除去率が低下する。より好ましい第一の触媒と第
三の触媒の重量比は４：１〜１：４である。In the present invention, the weight ratio of the first catalyst to the third 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 become large, and the removal rate of carbon monoxide and hydrocarbons decreases. A more preferable weight ratio of the first catalyst to the third catalyst is 4: 1 to 1: 4.
【００３７】上述した構成の浄化材を用いれば、２００
〜６００℃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 constitution is used,
In a wide temperature range of up to 600 ° C., good nitrogen oxides can be removed even with exhaust gas containing about 10% of water.
【００３８】次に、本発明の方法について説明する。ま
ず、排ガス浄化材を、第一の触媒が排ガスの入口に面
し、第三の触媒が排ガスの出口に面し、第二の触媒が第
一の触媒と第二の触媒の間に位置するように、排ガス導
管の途中に設置する。Next, the method of the present invention will be described. First, in the exhaust gas purifying material, the first catalyst faces the exhaust gas inlet, the third catalyst faces the exhaust gas outlet, and the second catalyst is located between the first catalyst and the second catalyst. Install in the middle of the exhaust gas pipe.
【００３９】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。Although the exhaust gas contains ethylene, propylene and the like as residual hydrocarbons to some extent, it is generally not sufficient to reduce NOx in the exhaust gas, and therefore hydrocarbons or oxygen-containing organic compounds are externally added. The reducing agent is introduced into the exhaust gas. The introduction position of the reducing agent is upstream of the position where the purification material is installed.
【００４０】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、アセチレン、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、エタノール等のアルコー
ル類を用いることができる。As the hydrocarbon introduced from the outside, a gas 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. Specific examples of the liquid hydrocarbon in the standard state include hydrocarbons such as acetylene, light oil, cetane, heptane, and kerosene. As the oxygen-containing organic compound, alcohols such as ethanol can be used.
【００４１】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、重量比（添加する還元剤の重量／排ガス
中の窒素酸化物の重量）が０．１〜５となるようにする
のが好ましい。この重量比が０．１未満であると、窒素
酸化物の除去率が大きくならない。一方、５を超える
と、燃費悪化につながる。The amount of the hydrocarbon or oxygen-containing organic compound introduced from the outside should be such that the weight ratio (weight of reducing agent added / weight of nitrogen oxide in exhaust gas) is 0.1 to 5. preferable. 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.
【００４２】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℃未満であると還元剤と窒素
酸化物との反応が進行せず、良好な窒素酸化物の除去を
行うことができない。一方、６００℃を超す温度とする
と炭化水素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、３００〜５００℃である。Further, in the present invention, the temperature of the exhaust gas at the purification material installation site, which is the 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 reaction between the reducing agent and the nitrogen oxide does not proceed, and the nitrogen oxide cannot be removed satisfactorily. On the other hand, when the temperature exceeds 600 ° C, the combustion of the hydrocarbon or oxygen-containing organic compound itself starts,
Nitrogen oxide cannot be reduced and removed. A preferable exhaust gas temperature is 300 to 500 ° C.
【００４３】[0043]
【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、同様のペレ
ット状アルミナ５ｇに硝酸銀、硝酸銅水溶液を用いて、
銀を２重量％、銅を０．０７重量％担持し、乾燥後、６
００℃まで焼成し、第二の触媒を調製した。さらに、同
様のペレット状アルミナ２ｇに塩化白金酸水溶液を用い
て、Ptを０．２重量％担持し、乾燥後、７００℃まで焼
成し、第三の触媒を調製した。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
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. In addition, the same pellet-shaped alumina 5g, using silver nitrate, copper nitrate aqueous solution,
After supporting 2% by weight of silver and 0.07% by weight of copper, after drying, 6
The second catalyst was prepared by firing to 00 ° C. Further, 2 g of the same pellet-shaped alumina was loaded with 0.2% by weight of Pt by using an aqueous solution of chloroplatinic acid, dried and calcined to 700 ° C. to prepare a third catalyst.
【００４４】浄化材を、排ガスの流入側から順に、銀系
第一の触媒３．７５ｇ、銀、銅系第二の触媒３．７５
ｇ、Pt系第三の触媒１．８ｇを組み合わせて浄化材と
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１２，０００ｈ-1、銀系触
媒とPt系触媒の接触時間はそれぞれ０．０５、０．０２
５秒・ｇ／ml）、反応管内の排ガス温度を２００〜６０
０℃の範囲に保ち、プロピレンと窒素酸化物とを反応さ
せた。The purifying materials, in order from the exhaust gas inflow side, were 3.75 g of a silver-based first catalyst, 3.75 g of silver and a copper-based second catalyst.
g, and 1.8 g of a Pt-based third catalyst were combined to form a purifying 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 12 1,000 h -1 , the contact time between the silver-based catalyst and the Pt-based catalyst is 0.05 and 0.02, respectively.
5 seconds ・ g / ml), the exhaust gas temperature in the reaction tube is 200-60
Maintaining the temperature in the range of 0 ° C., propylene was reacted with nitrogen oxide.
【００４５】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、一酸化炭素及び炭化水素の除去率を求めた。結果を
表２に示す。The concentration of nitrogen oxides in the gas after passing through the reaction tube was measured by a chemiluminescence type nitrogen oxides analyzer to determine the removal rates of nitrogen oxides, carbon monoxide and hydrocarbons. The results are shown in Table 2.
【００４６】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 1714 ppm （窒素酸化物の重量の３倍） 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 1714 ppm (3 times the weight of nitrogen oxides) Balance of nitrogen
【００４７】実施例２ 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（直
径20mm、長さ約１２．６mm）に硝酸銀、硝酸銅水溶液を
用いて、粉末状γ−アルミナに銀が２重量％、銅が０．
０７重量％担持されている触媒１ｇをコートし、乾燥
後、６００℃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（直径20mm、長さ約６mm）に、
粉末状γ−アルミナにPtが０．２重量％、Rhが０．２重
量％担持されている触媒０．５ｇ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、銀銅系浄化材、Pt系浄化材の順に
組み合わせて、反応管内にセットし、プロピレンの代わ
りに窒素酸化物の３倍重量の軽油を用いるほかは、表１
と同組成のガスで評価した（全体の見かけ空間速度約１
２，０００ｈ-1）。実験結果を表２に示す。 Example 2 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. Further, silver nitrate and copper nitrate aqueous solution were used for the same honeycomb shaped body (diameter 20 mm, length about 12.6 mm), and powdery γ-alumina contained 2% by weight of silver and 0.1% of copper.
1 g of the catalyst supported by 07% by weight was coated, dried, and calcined to 600 ° C. to prepare a purification material. further,
In the same honeycomb shaped body (diameter 20 mm, length about 6 mm),
0.5 g of a catalyst supporting 0.2% by weight of Pt and 0.2% by weight of Rh was coated on powdery γ-alumina, and after drying,
A purification material was prepared by firing to 700 ° C. From the inflow side of the exhaust gas, a silver-based purification material, a silver-copper-based purification material, and a Pt-based purification material are combined in this order, set in the reaction tube, and gas oil with a weight three times that of nitrogen oxide is used instead of propylene. Table 1
Was evaluated with a gas of the same composition as (total apparent space velocity of about 1
2,000 h -1 ). The experimental results are shown in Table 2.
【００４８】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％担持してなる浄化材７．５０ｇ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
果を表２に示す。 Comparative Example 1 In the same manner as in Example 1, 10 g of γ-alumina pellets
7.50 g of a purifying material having 2% by weight of silver loaded therein was set in a reaction tube, and the gas having the composition shown in Table 1 was evaluated. The experimental results are shown in Table 2.
【００４９】 表２ 窒素酸化物（ＮＯｘ）、一酸化炭素（ＣＯ）、炭化水素（ＨＣ）の除去率 反応温度 除去成分 除去率（％） （℃） 実施例１ 実施例２ 比較例１ ２５０ ＮＯｘ ３０ ２５ ０ ＣＯ ７５ ７８ ４０ ＨＣ ５０ ５２ ３５ ３００ ＮＯｘ ５２ ４５ ８ ＣＯ ９０ ９０ ５０ ＨＣ ６５ ７０ ４０ ４００ ＮＯｘ ６７ ５７ ４７ ＣＯ ９８ １００ ６０ ＨＣ ９５ ９５ ６５ ５００ ＮＯｘ ７０ ７０ ７２ ＣＯ １００ １００ ７０ ＨＣ １００ １００ ７５ ５５０ ＮＯｘ ６８ ７２ ６８ ＣＯ １００ １００ ７５ ＨＣ １００ １００ ８０ Table 2 Nitrogen oxide (NOx), carbon monoxide (CO), and hydrocarbon (HC) removal rates Reaction temperature Removal components Removal rate (%) (° C) Example 1 Example 2 Comparative Example 1 250 NOx 30 25 0 CO 75 75 78 40 HC 50 52 35 35 300 NOx 52 45 8 CO 90 90 50 50 HC 65 70 40 400 NOx 67 57 47 47 CO 98 100 60 60 HC 95 95 65 500 500 NOx 70 70 72 CO 75 100 100 100 70 550 NOx 68 72 68 CO 100 100 100 75 HC 100 100 80
【００５０】以上からわかるように、実施例１、２にお
いては、広い排ガス温度で窒素酸化物の良好な除去がみ
られた上、一酸化炭素及び炭化水素も効果的に除去され
た。一方、銀成分のみを担持した比較例１においては、
窒素酸化物除去の温度範囲が狭い。As can be seen from the above, in Examples 1 and 2, good removal of nitrogen oxides was observed over a wide range of exhaust gas temperatures, and carbon monoxide and hydrocarbons were also effectively removed. On the other hand, in Comparative Example 1 supporting only the silver component,
The temperature range for removing nitrogen oxides is narrow.
【００５１】[0051]
【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とともに、
一酸化炭素及び炭化水素も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, when the exhaust gas purifying material of the present invention is used, nitrogen oxides in exhaust gas containing excess oxygen can be efficiently removed in a wide temperature range, and
Carbon monoxide and hydrocarbons can also be removed. 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.
Claims (5)
する理論反応量より多い酸素とを含む燃焼排ガスから窒
素酸化物を還元除去するとともに、一酸化炭素及び炭化
水素を酸化除去する排ガス浄化材において、浄化材の排
ガス流入側から流出側に順に第一〜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として銀
又は銀酸化物０．２〜１５重量％（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
種として銀又は銀酸化物０．２〜１５重量％（元素換算
値）と銅又は銅酸化物２重量％以下（元素換算値）とを
担持してなり、前記第三の触媒が多孔質の無機酸化物に
活性種として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２重量％以下を担持してなるこ
とを特徴とする排ガス浄化材。1. An exhaust gas purifying material for reducing and removing nitrogen oxides and oxidizing and removing carbon monoxide and hydrocarbons from a combustion exhaust gas containing nitrogen oxides and oxygen in a larger amount than the theoretical reaction amount for coexisting unburned components. In, having a first to third catalyst in order from the exhaust gas inflow side of the purification material to the outflow side,
The first catalyst comprises silver or silver oxide 0.2 to 15% by weight (element conversion value) as an active species supported on a porous inorganic oxide, and the second catalyst is a porous inorganic oxide. As the active species, 0.2 to 15% by weight of silver or silver oxide (elemental conversion value) and 2% by weight or less of copper or copper oxide (elemental conversion value) are supported, and the third catalyst is An exhaust gas purifying material, comprising 2% by weight or less of an element selected from the group consisting of Pt, Pd, Ru, Rh, and Ir as an active species on a porous inorganic oxide.
て、前記第一、第二、及び第三の触媒の内の一つ以上が
セラッミクス製又は金属製の基体の表面にコートされた
ものであることを特徴とする排ガス浄化材。2. The exhaust gas purifying material according to claim 1, wherein one or more of the first, second and third catalysts are coated on the surface of a ceramic or metal substrate. Exhaust gas purification material characterized by being present.
て、前記第一、第二、及び第三の触媒の内の一つ以上が
ペレット状又は顆粒状であることを特徴とする排ガス浄
化材。3. The exhaust gas purifying material according to claim 1, wherein at least one of the first, second, and third catalysts is in the form of pellets or granules. .
浄化材において、前記多孔質無機酸化物が、第一及び第
二の触媒ではγ−アルミナ又はアルミナ系複合酸化物
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。4. The exhaust gas purifying material according to claim 1, wherein the porous inorganic oxide is γ-alumina or an alumina-based composite oxide in the first and second catalysts, 2. The exhaust gas purifying material, wherein the catalyst of (1) is any one of alumina, titania, and zirconia, or a composite oxide composed of two or more thereof.
浄化材を用い、窒素酸化物と、共存する未燃焼成分に対
する理論反応量より多い酸素とを含む燃焼排ガスから窒
素酸化物を還元除去するとともに、一酸化炭素及び炭化
水素を酸化除去する排ガス浄化方法において、前記排ガ
ス浄化材を排ガス導管の途中に設置し、前記浄化材の上
流側で炭化水素又は含酸素有機化合物を添加した排ガス
を、２００〜６００℃において前記浄化材に接触させ、
もって前記排ガス中の炭化水素又は含酸素有機化合物と
の反応により前記窒素酸化物、一酸化炭素及び炭化水素
を除去することを特徴とする排ガス浄化方法。5. The exhaust gas purifying material according to claim 1, which is used to remove nitrogen oxides from combustion exhaust gas containing nitrogen oxides and oxygen in an amount larger than a theoretical reaction amount for coexisting unburned components. In the exhaust gas purification method of reducing and removing carbon monoxide and hydrocarbons by oxidation, the exhaust gas purifying material is installed in the middle of an exhaust gas conduit, and a hydrocarbon or an oxygen-containing organic compound is added on the upstream side of the purifying material. Exhaust gas is contacted with the purification material at 200 to 600 ° C.,
Therefore, the exhaust gas purification method characterized in that the nitrogen oxides, carbon monoxide and hydrocarbons are removed by a reaction with the hydrocarbons or oxygen-containing organic compounds in the exhaust gas.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5048613A JPH06238166A (en) | 1993-02-15 | 1993-02-15 | Cleaning material for exhaust gas and cleaning method for exhaust gas |
| EP93310608A EP0605251A1 (en) | 1992-12-28 | 1993-12-29 | Exhaust gas cleaner |
| US08/434,915 US5589432A (en) | 1992-12-28 | 1995-05-04 | Exhaust gas cleaner and method for cleaning same |
| US08/532,260 US5658543A (en) | 1992-12-28 | 1995-09-22 | Exhaust gas cleaner and method for cleaning same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5048613A JPH06238166A (en) | 1993-02-15 | 1993-02-15 | Cleaning material for exhaust gas and cleaning method for exhaust gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06238166A true JPH06238166A (en) | 1994-08-30 |
Family
ID=12808268
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5048613A Pending JPH06238166A (en) | 1992-12-28 | 1993-02-15 | Cleaning material for exhaust gas and cleaning method for exhaust gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06238166A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08182920A (en) * | 1994-11-04 | 1996-07-16 | Agency Of Ind Science & Technol | Waste gas purifying material and purification of waste gas |
| JP2017029914A (en) * | 2015-07-31 | 2017-02-09 | ダイハツ工業株式会社 | Catalyst for exhaust purification |
-
1993
- 1993-02-15 JP JP5048613A patent/JPH06238166A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08182920A (en) * | 1994-11-04 | 1996-07-16 | Agency Of Ind Science & Technol | Waste gas purifying material and purification of waste gas |
| JP2017029914A (en) * | 2015-07-31 | 2017-02-09 | ダイハツ工業株式会社 | Catalyst for exhaust purification |
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