JPH07275709A - Material and method for purifying exhaust gas - Google Patents
Material and method for purifying exhaust gasInfo
- Publication number
- JPH07275709A JPH07275709A JP6092962A JP9296294A JPH07275709A JP H07275709 A JPH07275709 A JP H07275709A JP 6092962 A JP6092962 A JP 6092962A JP 9296294 A JP9296294 A JP 9296294A JP H07275709 A JPH07275709 A JP H07275709A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- catalyst
- oxide
- inorganic oxide
- 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
- 239000000463 material Substances 0.000 title claims abstract description 87
- 238000000034 method Methods 0.000 title claims description 31
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims abstract description 250
- 239000007789 gas Substances 0.000 claims abstract description 99
- 239000003054 catalyst Substances 0.000 claims abstract description 85
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 50
- 229910052709 silver Inorganic materials 0.000 claims abstract description 47
- 239000004332 silver Substances 0.000 claims abstract description 47
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 25
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 25
- 229910052707 ruthenium Inorganic materials 0.000 claims abstract description 17
- 238000002485 combustion reaction Methods 0.000 claims abstract description 16
- 229910052741 iridium Inorganic materials 0.000 claims abstract description 16
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 12
- 238000000746 purification Methods 0.000 claims description 62
- 229910052809 inorganic oxide Inorganic materials 0.000 claims description 57
- 238000006243 chemical reaction Methods 0.000 claims description 50
- 229930195733 hydrocarbon Natural products 0.000 claims description 43
- 150000002430 hydrocarbons Chemical class 0.000 claims description 43
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 37
- 229910052760 oxygen Inorganic materials 0.000 claims description 37
- 239000001301 oxygen Substances 0.000 claims description 37
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 31
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 29
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 29
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 24
- 229910052737 gold Inorganic materials 0.000 claims description 18
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 17
- 150000002894 organic compounds Chemical class 0.000 claims description 17
- 229910052763 palladium Inorganic materials 0.000 claims description 17
- 229910052751 metal Inorganic materials 0.000 claims description 16
- 239000002184 metal Substances 0.000 claims description 16
- 229910052703 rhodium Inorganic materials 0.000 claims description 15
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 14
- 239000002131 composite material Substances 0.000 claims description 12
- 239000000446 fuel Substances 0.000 claims description 12
- 229910052750 molybdenum Inorganic materials 0.000 claims description 11
- 229910052758 niobium Inorganic materials 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 10
- 238000007254 oxidation reaction Methods 0.000 claims description 10
- 229910052715 tantalum Inorganic materials 0.000 claims description 10
- 230000003647 oxidation Effects 0.000 claims description 9
- 239000000377 silicon dioxide Substances 0.000 claims description 9
- 239000008188 pellet Substances 0.000 claims description 5
- 229940100890 silver compound Drugs 0.000 claims description 5
- 150000003379 silver compounds Chemical class 0.000 claims description 5
- 238000011144 upstream manufacturing Methods 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
- 229910052799 carbon Inorganic materials 0.000 claims description 2
- 239000000919 ceramic Substances 0.000 claims description 2
- 239000011248 coating agent Substances 0.000 claims description 2
- 238000000576 coating method Methods 0.000 claims description 2
- 239000008187 granular material Substances 0.000 claims description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 abstract description 45
- 238000000151 deposition Methods 0.000 abstract 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 66
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 30
- 239000004215 Carbon black (E152) Substances 0.000 description 22
- 239000003638 chemical reducing agent Substances 0.000 description 19
- 239000000758 substrate Substances 0.000 description 18
- 229910021529 ammonia Inorganic materials 0.000 description 15
- 239000007864 aqueous solution Substances 0.000 description 15
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 12
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- 229910001868 water Inorganic materials 0.000 description 11
- 239000002245 particle Substances 0.000 description 10
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 7
- 238000010304 firing Methods 0.000 description 7
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 6
- 239000002253 acid Substances 0.000 description 5
- 125000004432 carbon atom Chemical group C* 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- 238000006722 reduction reaction Methods 0.000 description 5
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 5
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000011068 loading method Methods 0.000 description 4
- 239000012299 nitrogen atmosphere Substances 0.000 description 4
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- 238000010531 catalytic reduction reaction Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 229910052878 cordierite Inorganic materials 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 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 3
- -1 etc.) Inorganic materials 0.000 description 3
- 239000003502 gasoline Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 150000002431 hydrogen Chemical class 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 235000006408 oxalic acid Nutrition 0.000 description 3
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 3
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 3
- 229910001961 silver nitrate Inorganic materials 0.000 description 3
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 3
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 2
- 150000001335 aliphatic alkanes Chemical class 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 150000001345 alkine derivatives Chemical class 0.000 description 2
- 150000003863 ammonium salts Chemical class 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 239000003350 kerosene Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 150000003891 oxalate salts Chemical class 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000012629 purifying agent Substances 0.000 description 2
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 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
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229910021607 Silver chloride Inorganic materials 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
- 238000009835 boiling Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 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
- 239000000295 fuel oil Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000003779 heat-resistant material Substances 0.000 description 1
- 150000003840 hydrochlorides Chemical class 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 1
- 229910001923 silver oxide Inorganic materials 0.000 description 1
- 238000003980 solgel method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052815 sulfur oxide 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
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 for 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 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、3L422
、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 the 59th Annual Meeting of the Chemical Society of Japan
(1990) 2A526, 60th Autumn Meeting (1990) 3L420, 3L422
, 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ことが
わかった。そこで、本発明者らは、排ガス流入側に銀系
触媒、流出側に白金系触媒を有し、１０％の水分を含む
排ガスでも、効果的に窒素酸化物を除去できるととも
に、一酸化炭素及び炭化水素も除去できる浄化材を先に
提案した（特願平４−３２８８９５号）。しかし、高い
空間速度下での窒素酸化物等の除去率はまだ十分ではな
い。However, it has been found that these methods have a narrow temperature range for removing nitrogen oxides and that the exhaust gas containing water has a significantly low nitrogen oxide removal rate. Therefore, the present inventors have a silver-based catalyst on the exhaust gas inflow side and a platinum-based catalyst on the outflow side, and can effectively remove nitrogen oxides even with exhaust gas containing 10% water, We have previously proposed a purification material that can also remove hydrocarbons (Japanese Patent Application No. 4-328895). However, the removal rate of nitrogen oxides, etc. under high space velocity is not yet sufficient.
【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とともに、残留及び未反
応の一酸化炭素及び炭化水素も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 removing nitrogen oxides and also oxidizing and removing residual and unreacted 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（ａ）銀成
分と（ｂ）Ｗ、Ｖ系成分と（ｃ）白金系成分を担持して
なる触媒上で、エタノールなどの有機化合物が、酸素及
び窒素酸化物を含む排ガスと反応し、窒素酸化物を窒素
ガスに還元するとともに、副生成物としてアンモニアを
生成していることを見出した。上記銀系触媒と、アンモ
ニアを還元剤として窒素酸化物を還元できる（ｄ）Ｗ、
Ｖ系成分と（ｅ）白金系成分を担持してなる触媒とを組
み合わせて形成される排ガス浄化材を用い、排ガス中に
炭化水素及び／又は炭素数２以上の含酸素有機化合物、
又はそれらを含む燃料を添加し、特定の温度及び空間速
度で上記の浄化材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 inventors have found that (a) a silver component, (b) W, a V-based component, and (c) a platinum-based inorganic oxide in a porous inorganic oxide. On the catalyst supporting the components, an organic compound such as ethanol reacts with the exhaust gas containing oxygen and nitrogen oxides to reduce the nitrogen oxides to nitrogen gas, and also to produce ammonia as a by-product. I found that. Nitrogen oxides can be reduced using the above silver-based catalyst and ammonia as a reducing agent (d) W,
An exhaust gas purifying material formed by combining a V-based component and a catalyst supporting (e) a platinum-based component is used, and a hydrocarbon and / or an oxygen-containing organic compound having 2 or more carbon atoms in the exhaust gas,
Alternatively, if a fuel containing them is added and the exhaust gas is brought into contact with the above-mentioned purification material at a specific temperature and space velocity, nitrogen oxides can be effectively removed in a wide temperature range even in the exhaust gas containing 10% water. They have discovered that they can, and have completed the present invention.
【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、残留及び未
反応の一酸化炭素及び炭化水素も酸化除去する本発明の
排ガス浄化材は、（１）多孔質の無機酸化物に（ａ）前
記無機酸化物の０．２〜１５重量％（元素換算値）の銀
及び／又は銀化合物、又はそれらの混合物と、（ｂ）前
記無機酸化物の５重量％以下（元素換算値）のＷ、Ｖ、
Ｍｎ、Ｍｏ、Ｎｂ及びＴａからなる群より選ばれた少な
くとも１種の元素と、（ｃ）前記無機酸化物の１重量％
以下（元素換算値）のPt、Pd、Ru、Rh、Ir及びAuからな
る群より選ばれた少なくとも１種の元素とを担持してな
る第一の触媒と、（２）多孔質の無機酸化物に（ｄ）前
記無機酸化物の１０重量％以下（金属元素換算値）の
Ｗ、Ｖ、Ｍｎ、Ｍｏ、Ｎｂ及びＴａからなる群より選ば
れた少なくとも一種の元素の酸化物と、（ｅ）前記無機
酸化物の５重量％以下（元素換算値）のPt、Pd、Ru、R
h、Ir及びAuからなる群より選ばれた少なくとも１種の
元素とを担持してなる第二の触媒とからなることを特徴
とする。That is, the nitrogen oxides are reduced and removed from the combustion exhaust gas containing the nitrogen oxides and oxygen in a larger amount than the theoretical reaction amount with respect to the coexisting unburned components, and residual and unreacted carbon monoxide and hydrocarbons are also oxidized. The exhaust gas purifying material of the present invention to be removed is (1) a porous inorganic oxide, and (a) 0.2 to 15% by weight (elemental conversion value) of silver and / or a silver compound of the inorganic oxide, or those. And (b) 5% by weight or less (elemental conversion value) of W and V of the inorganic oxide,
At least one element selected from the group consisting of Mn, Mo, Nb and Ta, and (c) 1% by weight of the inorganic oxide
A first catalyst supporting at least one element selected from the group consisting of Pt, Pd, Ru, Rh, Ir, and Au below (elemental conversion value), and (2) porous inorganic oxidation (D) an oxide of at least one element selected from the group consisting of W, V, Mn, Mo, Nb, and Ta of 10% by weight or less (metal element conversion value) of the inorganic oxide, and (e) ) Pt, Pd, Ru, R of 5% by weight or less (elemental conversion value) of the inorganic oxide
It is characterized by comprising a second catalyst carrying at least one element selected from the group consisting of h, Ir and Au.
【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、残留及び未反応
の一酸化炭素及び炭化水素も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／又は炭素数２
以上の含酸素有機化合物、又はそれを含む燃料を添加し
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含酸素有機化合物との反
応により前記窒素酸化物を除去するとともに、残留及び
未反応の一酸化炭素及び炭化水素も酸化除去することを
特徴とする。Further, the nitrogen oxides are reduced and removed from the combustion exhaust gas containing nitrogen oxides and oxygen in a larger amount than the theoretical reaction amount for coexisting unburned components, and residual and unreacted carbon monoxide and hydrocarbons are also oxidized. The exhaust gas purification method of the present invention to remove, the exhaust gas purification material is installed in the middle of the exhaust gas conduit, the exhaust gas purification material is installed in the middle of the exhaust gas conduit, hydrocarbons and / or carbon number upstream of the purification material Two
Exhaust gas added with the oxygen-containing organic compound or the fuel containing the oxygen-containing organic compound is brought into contact with the purification material at 150 to 650 ° C., thereby removing the nitrogen oxides by reaction with the oxygen-containing organic compound in the exhaust gas. In addition, residual and unreacted carbon monoxide and hydrocarbons are also oxidized and removed.
【００１３】以下、本発明を詳細に説明する。本発明で
は、（１）多孔質の無機酸化物に（ａ）前記無機酸化物
の０．２〜１５重量％（元素換算値）の銀及び／又は銀
化合物、又はそれらの混合物と、（ｂ）前記無機酸化物
の５重量％以下（元素換算値）のＷ、Ｖ、Ｍｎ、Ｍｏ、
Ｎｂ及びＴａからなる群より選ばれた少なくとも１種の
元素と、（ｃ）前記無機酸化物の１重量％以下（元素換
算値）のPt、Pd、Ru、Rh、Ir及びAuからなる群より選ば
れた少なくとも１種の元素とを担持してなる第一の触媒
と、（２）多孔質の無機酸化物に（ｄ）前記無機酸化物
の１０重量％以下（金属元素換算値）のＷ、Ｖ、Ｍｎ、
Ｍｏ、Ｎｂ及びＴａからなる群より選ばれた少なくとも
一種の元素の酸化物と、（ｅ）前記無機酸化物の５重量
％以下（元素換算値）のPt、Pd、Ru、Rh、Ir及びAuから
なる群より選ばれた少なくとも１種の元素とを担持して
なる第二の触媒とから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炭化水素及び
／又は炭素数２以上の含酸素有機化合物、又はそれを含
む燃料を添加した排ガスをこの浄化材に接触させて、排
ガス中の窒素酸化物を還元除去する。本発明では、第一
の触媒と第二の触媒を組み合わせて用いるが、排ガス流
入側に第一の触媒を、流出側に第二の触媒を配置するの
が好ましい。このように配置することによって、広い排
ガス温度領域で窒素酸化物を効果的に還元除去すること
ができる。The present invention will be described in detail below. In the present invention, (1) a porous inorganic oxide, (a) 0.2 to 15% by weight (elemental conversion value) of silver and / or a silver compound of the inorganic oxide, or a mixture thereof, and (b) ) W, V, Mn, Mo of 5% by weight or less (elemental conversion value) of the inorganic oxide,
From at least one element selected from the group consisting of Nb and Ta, and (c) from the group consisting of Pt, Pd, Ru, Rh, Ir and Au in an amount of 1% by weight or less (elemental conversion value) of the inorganic oxide. A first catalyst supporting at least one selected element, and (2) a porous inorganic oxide, and (d) W of 10% by weight or less (metal element conversion value) of the inorganic oxide. , V, Mn,
An oxide of at least one element selected from the group consisting of Mo, Nb and Ta, and (e) 5 wt% or less (elemental conversion value) of Pt, Pd, Ru, Rh, Ir and Au of the inorganic oxide. An exhaust gas purification material comprising a second catalyst carrying at least one element selected from the group consisting of: is installed in the exhaust gas conduit, and hydrocarbons and / or hydrocarbons are provided upstream of the installation position of the purification material. Exhaust gas to which an oxygen-containing organic compound having 2 or more carbon atoms or a fuel containing the same is added is brought into contact with this purifying material to reduce and remove nitrogen oxides in the exhaust gas. In the present invention, the first catalyst and the second catalyst are used in combination, but it is preferable to dispose the first catalyst on the exhaust gas inflow side and the second catalyst on the outflow side. By arranging in this way, nitrogen oxides can be effectively reduced and removed in a wide exhaust gas temperature range.
【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
てなる第一及び第二の触媒をそれぞれ浄化材基体にコー
トしてなる浄化材、又は粉末状の多孔質無機酸化物を浄
化材基体にコートした後、触媒活性種を担持してなる浄
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、アルミナ及びそれら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。In a first preferred form of the exhaust gas purifying material of the present invention, the purifying material base is coated with the first and second catalysts, each of which is a powdery porous inorganic oxide carrying a catalytically active species. Or a powdery porous inorganic oxide coated on a purifying material base, and then carrying a catalytically active species. 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, cordierite, mullite, alumina and their composites are preferably used. 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。また、基体は入口部分、
出口部分など二つ又は二つ以上の部分を組み合わせて用
いることもできる。基体の構造としては、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。上記
第一の触媒及び第二の触媒は同じ基体の異なる位置にコ
ートしてもよいし、異なる基体にコートしてから組み合
わせて用いてもよい。The shape and size of the substrate of the exhaust gas purifying material is
Various changes can be made according to the purpose. Also, the base body is the inlet portion,
It is also possible to use two or more parts such as an outlet part in combination. Examples of the structure of the substrate 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. The first catalyst and the second catalyst may be coated on different positions of the same substrate, or may be coated on different substrates and then used in combination.
【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、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し、又は触媒活性種を担持した多
孔質無機酸化物をペレット状、顆粒状又は粉末状に成型
してなる触媒を所望形状のケーシングに充填してなる浄
化材である。A second preferred embodiment of the exhaust gas purifying material of the present invention is a pellet-like, granular-like or powder-like porous inorganic oxide carrying a catalytically active species, or a porous inorganic oxide carrying a catalytically active species. It is a purifying material obtained by filling a casing having a desired shape with a catalyst formed by molding an article into a pellet, granule or powder.
【００１７】本発明の浄化材には以下の二つの触媒が形
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(a) 銀及び／又は銀
化合物、又はそれらの混合物と、(b) Ｗ、Ｖ、Ｍｎ、Ｍ
ｏ、Ｎｂ及びＴａとからなる群より選ばれた少なくとも
一種の金属元素と、（ｃ）Pt、Pd、Ru、Rh、Ir及びAuか
らなる群より選ばれた少なくとも１種の元素とを担持し
てなる。多孔質の無機酸化物としては、多孔質のアルミ
ナ、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
ミナ単独、又はシリカ、チタニア及びジルコニアからな
る群より選ばれた少なくとも一種を含むアルミナ系複合
酸化物を用いる。多孔質の無機酸化物にアルミナ系複合
酸化物を用いる場合、アルミナの含有率が５０重量％以
上であるのが好ましい。アルミナの含有率が５０重量％
未満であると、浄化材の初期除去特性が大きく低下す
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又はそれを含有す
る燃料と排ガス中の窒素酸化物との反応が効率良く起こ
る。特にアルミナ系複合酸化物を用いることにより、Ｓ
Ｏ2 ガスの存在下でも、浄化材の耐久性、耐熱性は向上
するとともに、ＳＯ2 の酸化を抑制することができる。The following two catalysts are formed on the purification material of the present invention. (1) First catalyst The first catalyst comprises a porous inorganic oxide (a) silver and / or a silver compound, or a mixture thereof, and (b) W, V, Mn, M.
supporting at least one metal element selected from the group consisting of o, Nb and Ta, and (c) at least one element selected from the group consisting of Pt, Pd, Ru, Rh, Ir and Au. It becomes. As the porous inorganic oxide, it is possible to use porous alumina, silica, titania, zirconia and their composite oxides, preferably γ-alumina alone, or a group consisting of silica, titania and zirconia. An alumina-based composite oxide containing at least one selected from the above is used. When the alumina-based composite oxide is used as the porous inorganic oxide, the content of alumina is preferably 50% by weight or more. Alumina content of 50% by weight
If it is less than the above range, the initial removal characteristics of the purifying material are significantly deteriorated. By using γ-alumina or an alumina-based composite oxide, the reaction between the added oxygen-containing organic compound or the fuel containing the same and the nitrogen oxide in the exhaust gas occurs efficiently. In particular, by using an alumina-based composite oxide, S
Even in the presence of O 2 gas, the durability and heat resistance of the purification material are improved, and the oxidation of SO 2 can be suppressed.
【００１８】第一の触媒で用いるアルミナなどの多孔質
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。より好ましい多孔質無機酸化物の比表面積は３０ｍ
2 ／ｇ以上である。The specific surface area of the porous inorganic oxide such as alumina used in the first catalyst is preferably 10 m 2 / g or more. When the specific surface area is less than 10 m 2 / g, the contact area between the exhaust gas and the inorganic oxide (and the silver component supported on it) becomes small, and the nitrogen oxide cannot be removed well. More preferable specific surface area of the porous inorganic oxide is 30 m
2 / g or more.
【００１９】多孔質無機酸化物に担持する銀及び／又は
銀化合物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、銀成分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２０〜２
００ｎｍ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。The silver and / or silver compound supported on the porous inorganic oxide 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, the better the reaction characteristics, but the average particle size is 10 nm.
If it is less than the above range, the oxidation reaction of the reducing agent hydrocarbon or the oxygen-containing organic compound proceeds too much, and the nitrogen oxide removal rate is low. On the other hand, when the average particle size of the silver component particles exceeds 1000 nm, the reaction characteristics of the silver component deteriorate, and the nitrogen oxide removal rate decreases. The preferable average particle size of silver component particles is 20 to 2
00 nm. Here, the average particle diameter is obtained by the arithmetic mean of the diameters of the particles.
【００２０】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として、銀、銀酸化物、銀の
ハロゲン化物などが挙げられる。好ましい銀成分は銀及
び／又は塩化銀である。銀成分（ａ）の担持量は、排ガ
ス中に添加する有機化合物及び燃料の種類、排ガスとの
接触時間などによって多少変化するが、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％を超す量の銀成分を担持する
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０．５〜１２重量％である。Examples of the silver component supported on the above-mentioned inorganic oxide such as γ-alumina as an active species include silver, silver oxide and silver halide. The preferred silver component is silver and / or silver chloride. The amount of the silver component (a) supported varies slightly depending on the type of organic compound and fuel added to the exhaust gas, the contact time with the exhaust gas, and the like.
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, when a silver component in an amount exceeding 15% by weight is carried, the oxygen-containing organic compound itself is easily burned, and the nitrogen oxide removal rate is rather lowered. The amount of the silver component supported is preferably 0.5 to 12% by weight.
【００２１】Ｗ、Ｖ、Ｍｎ、Ｍｏ、Ｎｂ及びＴａのう
ち、Ｗ、Ｖ、Ｍｏ及び／又はＭｎを用いるのが好まし
く、Ｗ及び／又はＶを用いるのがより好ましい。第一の
触媒で無機酸化物に担持するＷ系酸化物（ｂ）の量は、
上述の多孔質の無機酸化物を基準（１００重量％）とし
て５重量％以下（金属元素換算値）とし、好ましくは
０．０１〜３重量％（金属元素換算値）とする。Ｗ系酸
化物の担持量が前記無機酸化物に対して、５重量％を超
しても効果に変化がない。Ｗ系酸化物を用いることによ
り、アンモニアを還元剤とする窒素酸化物の除去が可能
になる。また、本発明では、アンモニアによる窒素酸化
物の還元反応を促進する触媒であれば、Ｗ系酸化物に限
らず用いることが可能である。Of W, V, Mn, Mo, Nb and Ta, W, V, Mo and / or Mn are preferably used, and W and / or V are more preferably used. The amount of the W-based oxide (b) supported on the inorganic oxide by the first catalyst is
It is 5% by weight or less (metal element conversion value), preferably 0.01 to 3% by weight (metal element conversion value) based on the above-mentioned porous inorganic oxide (100% by weight). Even if the amount of the W-based oxide supported exceeds 5% by weight with respect to the inorganic oxide, the effect does not change. By using a W-based oxide, it becomes possible to remove nitrogen oxides using ammonia as a reducing agent. Further, in the present invention, any catalyst that promotes the reduction reaction of nitrogen oxides with ammonia can be used without being limited to W-based oxides.
【００２２】また、Pt、Pd、Ru、Rh、Ir及びAuのうち、
Pt、Pd、Ru、Rh及びAuの少なくとも一種を用いるのが好
ましく、特にPt、Pd及びAuの少なくとも一種が好まし
い。Pt、Pd、Ru、Rh、Ir及びAuの少なくとも一種の担持
量は無機酸化物を１００重量％として、１重量％以下
（元素換算値）とする。担持量が無機酸化物の１重量％
を超えると銀成分による除去効果が大きく低下する。な
お、担持量の下限値を０．０００１重量％とするのが好
ましい。より好ましい担持量は０．００５〜０．５重量
％である。Of Pt, Pd, Ru, Rh, Ir and Au,
It is preferable to use at least one of Pt, Pd, Ru, Rh, and Au, and particularly preferable is at least one of Pt, Pd, and Au. The loading amount of at least one of Pt, Pd, Ru, Rh, Ir and Au is 1% by weight or less (elemental conversion value) with 100% by weight of the inorganic oxide. Carrying amount is 1% by weight of inorganic oxide
If it exceeds, the removal effect by the silver component is greatly reduced. The lower limit of the supported amount is preferably 0.0001% by weight. A more preferable loading amount is 0.005 to 0.5% by weight.
【００２３】γ−アルミナ等の無機酸化物に銀成分、
Ｗ、Ｖ、Ｍｎ、Ｍｏ、Ｎｂ及びＴａの一種以上、Pt、P
d、Ru、Rh、Ir及びAuの一種以上を担持する方法として
は、公知の含浸法、沈澱法等を用いることができる。そ
の際、各元素のアンモニウム塩、しゅう酸塩、硫酸塩、
炭酸塩、硝酸塩又は塩酸塩等の混合水溶液に多孔質の無
機酸化物を浸漬するか、それぞれの元素化合物の水溶液
に順番に多孔質の無機酸化物を浸漬し、５０〜１５０
℃、特に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。焼成は、酸素雰囲
気、窒素雰囲気下や水素ガス流下で行うのが好ましい。
窒素雰囲気下や水素ガス流下で行う場合には、最後に３
００〜６５０℃で酸化処理するのが好ましい。Inorganic oxide such as γ-alumina, silver component,
One or more of W, V, Mn, Mo, Nb and Ta, Pt, P
As a method for supporting one or more of d, Ru, Rh, Ir and Au, a known impregnation method, a precipitation method or the like can be used. At that time, ammonium salts, oxalates, sulfates of each element,
50 to 150 by immersing the porous inorganic oxide in a mixed aqueous solution of carbonate, nitrate or hydrochloride, or by immersing the porous inorganic oxide in an aqueous solution of each elemental compound in order.
After drying at a temperature of about 70 ° C., it is preferable to raise the temperature step by step at 100 to 600 ° C. for firing. The firing is preferably performed in an oxygen atmosphere, a nitrogen atmosphere or a hydrogen gas flow.
When performing under a nitrogen atmosphere or under a flow of hydrogen gas, the last step is 3
It is preferable to perform the oxidation treatment at 00 to 650 ° 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
３００μｍ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、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 purifying material substrate is preferably 300 μm or less. With such a thickness, it is possible to prevent the purification material from being damaged by thermal shock during use. The method of forming the catalyst on the surface of the purification material substrate is performed by a known wash coat 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２０〜３００ｇ／リットルとす
るのが好ましい。触媒の量が２０ｇ／リットル未満では
良好なNOx の除去が行えない。一方、触媒の量が３００
ｇ／リットル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５０〜２５０
ｇ／リットルとする。Further, the amount of the first catalyst provided on the surface of the purification material substrate is preferably 20 to 300 g / liter of the purification material substrate. If the amount of catalyst is less than 20 g / liter, good NOx cannot be removed. On the other hand, the amount of catalyst is 300
If it exceeds g / liter, the removal property does not improve so much,
Pressure loss increases. More preferably, the first catalyst provided on the surface of the purification material substrate is 50 to 250 of the purification material substrate.
g / liter.
【００２６】（２）第二の触媒 第二の触媒は、多孔質無機酸化物に触媒活性種である
（ｄ）Ｗ、Ｖ、Ｍｎ、Ｍｏ、Ｎｂ及びＴａからなる群よ
り選ばれた少なくとも一種の元素の酸化物と、（ｅ）P
t、Pd、Ru、Rh、Ir及びAuとからなる群より選ばれた少
なくとも一種の金属元素とを担持してなる。多孔質無機
酸化物としては、チタニア、アルミナ、ジルコニア及び
シリカのいずれか又はそれらの複合酸化物などの多孔質
で表面積の大きい耐熱性のセラミックスが挙げられる。
好ましくはチタニア又はチタニアを含む複合酸化物を用
いる。(2) Second catalyst The second catalyst is at least one selected from the group consisting of (d) W, V, Mn, Mo, Nb and Ta which are catalytically active species in the porous inorganic oxide. Elemental oxides of (e) P
It carries at least one metal element selected from the group consisting of t, Pd, Ru, Rh, Ir and Au. Examples of the porous inorganic oxides include porous and large surface area heat-resistant ceramics such as titania, alumina, zirconia and silica, or composite oxides thereof.
Preferably, titania or a composite oxide containing titania is used.
【００２７】Ｗ、Ｖ、Ｍｏ、Ｍｎ、Ｎｂ及びＴａのう
ち、Ｗ、Ｖ、Ｍｏ及び／又はＭｎを用いるのが好まし
く、Ｗ及び／又はＶを用いるのがより好ましい。第二の
触媒で無機酸化物に担持するＷ系酸化物（ｄ）の量は、
上述の多孔質の無機酸化物を基準（１００重量％）とし
て１０重量％以下（金属元素換算値）とし、好ましくは
０．０１〜１０重量％、より好ましくは０．２〜８重量
％、さらに好ましくは０．５〜５重量％（金属元素換算
値）とする。Ｗ系酸化物の担持量が前記無機酸化物に対
して、１０重量％を超しても効果に変化がない。Ｗ系酸
化物を用いることにより、アンモニアを還元剤とする窒
素酸化物の除去が可能になる。また、本発明では、アン
モニアによる窒素酸化物の還元反応を促進する触媒であ
れば、Ｗ系酸化物に限らず用いることが可能である。Of W, V, Mo, Mn, Nb and Ta, W, V, Mo and / or Mn are preferably used, and W and / or V are more preferably used. The amount of the W-based oxide (d) supported on the inorganic oxide by the second catalyst is
Based on the above-mentioned porous inorganic oxide (100% by weight), 10% by weight or less (metal element conversion value), preferably 0.01 to 10% by weight, more preferably 0.2 to 8% by weight, further It is preferably 0.5 to 5% by weight (metal element conversion value). Even if the amount of the W-based oxide supported exceeds 10% by weight with respect to the inorganic oxide, the effect does not change. By using a W-based oxide, it becomes possible to remove nitrogen oxides using ammonia as a reducing agent. Further, in the present invention, any catalyst that promotes the reduction reaction of nitrogen oxides with ammonia can be used without being limited to W-based oxides.
【００２８】また、Pt、Pd、Ru、Rh、Ir及びAuのうち、
Pt、Pd、Ru、Rh及びAuの少なくとも一種を用いるのが好
ましく、特にPt、Pd及びAuの少なくとも一種が好まし
い。Pt、Pd、Ru、Rh、Ir及びAuの少なくとも一種の担持
量は無機酸化物を１００重量％として、５重量％以下
（元素換算値）とする。担持量が無機酸化物の５重量％
を超えると銀成分による除去効果が大きく低下する。な
お、担持量の下限値を０．０１重量％とするのが好まし
い。より好ましい担持量は０．１〜４重量％である。Of Pt, Pd, Ru, Rh, Ir and Au,
It is preferable to use at least one of Pt, Pd, Ru, Rh, and Au, and particularly preferable is at least one of Pt, Pd, and Au. The supported amount of at least one of Pt, Pd, Ru, Rh, Ir and Au is 5% by weight or less (elemental conversion value) with 100% by weight of the inorganic oxide. 5% by weight of inorganic oxide
If it exceeds, the removal effect by the silver component is greatly reduced. The lower limit of the supported amount is preferably 0.01% by weight. A more preferable loading amount is 0.1 to 4% by weight.
【００２９】第二の触媒におけるＷ系酸化物とPt、Pd、
Ru、Rh、Ir及びAuの一種以上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、粉末法等を用い
ることができる。その際、各元素のアンモニウム塩、し
ゅう酸塩、硫酸塩、炭酸塩、硝酸塩又は塩酸塩等の混合
水溶液に多孔質無機酸化物を浸漬するか、それぞれの元
素化合物水溶液に多孔質の無機酸化物を順番に浸漬し、
５０〜１５０℃、特に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。
この焼成は空気中、酸素雰囲気下、窒素雰囲気下、又は
水素ガス流下で行うが、窒素雰囲気下又は水素ガス流下
焼成したときは、最後に３００〜６５０℃で酸化処理を
行うと効果的である。The W-based oxide and Pt, Pd, and
As a method of supporting one or more of Ru, Rh, Ir and Au,
Known impregnation method, precipitation method, sol-gel method, powder method and the like can be used. At that time, the porous inorganic oxide is immersed in a mixed aqueous solution of ammonium salts, oxalates, sulfates, carbonates, nitrates or hydrochlorides of the respective elements, or the porous inorganic oxide is added to the aqueous solution of each element compound. Dip in order,
100-600 after drying at 50-150 ° C, especially 70 ° C
It is carried out by gradually raising the temperature at ℃ and firing.
This firing is performed in air, under an oxygen atmosphere, under a nitrogen atmosphere, or under a flow of hydrogen gas, but when firing under a nitrogen atmosphere or under a flow of hydrogen gas, it is effective to finally perform an oxidation treatment at 300 to 650 ° C. .
【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３００μ
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２０〜３００ｇ／
リットルとするのが好ましい。また、浄化材基体がチタ
ニアなどの多孔質無機酸化物からなるときは、それらに
Ｗ及び／又はＶの酸化物を所定量担持して浄化剤として
用いることができる。その他にＷ及び／又はＶの酸化物
を所定量担持したチタニア等の多孔質無機酸化物をハニ
カム等の成形体に成形して用いることができる。In the first preferred embodiment of the purification material, the thickness of the second catalyst provided on the purification material substrate is 300 μm.
It is preferably m or less. Further, the amount of the second catalyst provided on the surface of the purification material substrate is 20 to 300 g / of the purification material substrate.
It is preferably liter. Further, when the purifying material substrate is made of a porous inorganic oxide such as titania, a predetermined amount of W and / or V oxide can be supported on them to be used as a purifying agent. In addition, a porous inorganic oxide such as titania carrying a predetermined amount of W and / or V oxide may be molded into a molded body such as a honeycomb and used.
【００３１】本発明においては、第一の触媒と、第二の
触媒との重量比（多孔質無機酸化物と触媒活性種との合
計重量の比）は、１０：１〜１：２とするのが好まし
い。比率が１：２未満である（第一の触媒が少ない）
と、１５０〜６５０℃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１０：１を超
え、第二の触媒が少ないと、第一の触媒上でできたアン
モニアが反応せず、そのまま排出され、排出するガス中
のアンモニア濃度が増す。より好ましい第一触媒と第二
触媒の重量比は９：１〜１：１である。In the present invention, the weight ratio of the first catalyst and the second catalyst (the ratio of the total weight of the porous inorganic oxide and the catalytically active species) is 10: 1 to 1: 2. Is preferred. The ratio is less than 1: 2 (less first catalyst)
Then, in a wide temperature range of 150 to 650 ° C., the purification rate of nitrogen oxides is lowered overall. On the other hand, when the ratio exceeds 10: 1 and the amount of the second catalyst is small, the ammonia produced on the first catalyst does not react and is discharged as it is, and the ammonia concentration in the discharged gas increases. A more preferable weight ratio of the first catalyst to the second catalyst is 9: 1 to 1: 1.
【００３２】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。また、アンモニアはより優先的に二酸化窒素
と反応するため、窒素酸化物中の有害な二酸化窒素の割
合を減らすことができる。If the purifying material having the above 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. Also, ammonia reacts with nitrogen dioxide more preferentially, thus reducing the proportion of harmful nitrogen dioxide in the nitrogen oxides.
【００３３】次に、本発明の方法について説明する。ま
ず、第一の触媒と第二の触媒を有する排ガス浄化材を排
ガス導管の途中に設置する。好ましくは、第一の触媒が
排ガスの入口に面し、第二の触媒が排ガスの出口に面す
るように配置する。Next, the method of the present invention will be described. First, an exhaust gas purification material having a first catalyst and a second catalyst is installed in the middle of an exhaust gas conduit. Preferably, the first catalyst faces the exhaust gas inlet and the second catalyst faces the exhaust gas outlet.
【００３４】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／又は炭素数２以上の含酸素有機化合
物、又はそれらを含む混合燃料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 carbon atoms of 2 are externally added. The oxygen-containing organic compound or a reducing agent composed of a mixed fuel containing them is introduced into the exhaust gas. The introduction position of the reducing agent is upstream of the position where the purification material is installed.
【００３５】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。標準状態でガス状の
炭化水素としては、炭素数２以上のアルカン、アルケ
ン、又はアルキンが好ましい。標準状態で液体状の炭化
水素としては、具体的に、ヘプタン、セタン、灯油、軽
油、ガソリン及び重油等の炭化水素が挙げられる。その
中でも、沸点５０〜３５０℃の炭化水素が特に好まし
い。As the hydrocarbon introduced from the outside, gaseous or liquid alkane, alkene and / or alkyne in a standard state can be used. The gaseous hydrocarbon in the standard state is preferably an alkane, alkene, or alkyne having 2 or more carbon atoms. Specific examples of the liquid hydrocarbon in the standard state include hydrocarbons such as heptane, cetane, kerosene, light oil, gasoline and heavy oil. Among them, hydrocarbons having a boiling point of 50 to 350 ° C. are particularly preferable.
【００３６】外部から導入する含酸素有機化合物とし
て、炭素数２以上のエタノール、イソプロピルアルコー
ル等のアルコール類、又はそれらを含む燃料を用いるこ
とができる。外部から導入する還元剤の量は、重量比
（添加する還元剤の重量／排ガス中の窒素酸化物（Ｎ
Ｏ）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、重量比が５を超えると、
燃費悪化につながる。As the oxygen-containing organic compound introduced from the outside, alcohols having 2 or more carbon atoms such as ethanol and isopropyl alcohol, or fuel containing them can be used. The amount of the reducing agent introduced from the outside is the weight ratio (weight of the reducing agent to be added / nitrogen oxide (N
The weight of O) is preferably 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, if the weight ratio exceeds 5,
It leads to deterioration of fuel efficiency.
【００３７】また、炭化水素又は含酸素有機化合物を含
有する燃料を添加する場合、燃料としてガソリン、軽
油、灯油などを用いるのが好ましい。この場合、還元剤
の量は上記と同様に重量比（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
設定する。When a fuel containing a hydrocarbon or an oxygen-containing organic compound is added, it is preferable to use gasoline, light oil, kerosene or the like as the fuel. In this case, the amount of the reducing agent is set so that the weight ratio (weight of reducing agent to be added / weight of nitrogen oxide in exhaust gas) is 0.1 to 5 similarly to the above.
【００３８】本発明では、含酸素有機化合物、炭化水素
又はアンモニア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、浄化材の全体見かけ空間速度は 5
00,000ｈ-1以下とする。空間速度が 500,000ｈ-1を越え
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。好ましい空間速度は 450,000
ｈ-1以下、より好ましい空間速度は 300,000ｈ-1以下と
する。そのうち、第一の触媒における空間速度は 200,0
00ｈ-1以下、好ましくは 150,000ｈ-1以下とする。第一
の触媒の空間速度が 200,000ｈ-1を越えると、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。また、第二の触媒における空間速度は 250,0
00ｈ-1以下、好ましくは 200,000ｈ-1以下とする。第二
の触媒の空間速度が 250,000ｈ-1を越えると、炭化水
素、一酸化炭素などの酸化除去特性は低下する。なお、
排ガス中にＳＯ2 が存在する場合、第二の触媒における
空間速度は10,000〜 250,000ｈ-1とする。第二の触媒の
空間速度が10,000ｈ-1未満であると、ＳＯ2 が酸化され
やすくなるため好ましくない。In the present invention, the total apparent space velocity of the purifying material is 5 in order to efficiently reduce and remove nitrogen oxides by the oxygen-containing organic compound, hydrocarbon or ammonia.
It shall be 00,000h -1 or less. When the space velocity exceeds 500,000 h -1 , the reduction reaction of nitrogen oxides does not sufficiently occur and the removal rate of nitrogen oxides decreases. Preferred space velocity is 450,000
h -1 or less, more preferably space velocity and 300,000H -1 or less. Among them, the space velocity in the first catalyst is 200,0
It is set to 00h -1 or less, preferably 150,000h -1 or less. When the space velocity of the first catalyst exceeds 200,000 h -1 , the reduction reaction of nitrogen oxides does not sufficiently occur, and the removal rate of nitrogen oxides decreases. The space velocity in the second catalyst is 250,0
It is set to 00h -1 or less, preferably 200,000h -1 or less. When the space velocity of the second catalyst exceeds 250,000 h -1 , the oxidative removal characteristics of hydrocarbons, carbon monoxide, etc. deteriorate. In addition,
When SO 2 is present in the exhaust gas, the space velocity in the second catalyst is 10,000 to 250,000 h −1 . When the space velocity of the second catalyst is less than 10,000 h -1 , SO 2 is easily oxidized, which is not preferable.
【００３９】また、本発明では、還元剤と窒素酸化物と
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、還元剤自身の燃焼が
優先し、窒素酸化物の還元除去率が低下する。好ましい
排ガス温度は２５０〜６００℃である。Further, in the present invention, the temperature of the exhaust gas at the site where the reducing agent is reacted, where the reducing agent reacts with the nitrogen oxide, is maintained at 150 to 650 ° C. Exhaust gas temperature is 150
If the temperature is lower than ° 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 650 ° C., the reducing agent itself is preferentially burned and the reduction rate of nitrogen oxides is reduced. A preferable exhaust gas temperature is 250 to 600 ° C.
【００４０】[0040]
【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 市販の粉末状シリカ・アルミナ（ＳｉＯ2 含有量５重量
％、比表面積３５０ｍ2 ／ｇ）１０ｇに、硝酸銀水溶
液、塩化白金酸水溶液を用いて、銀を４重量％、白金を
０．０１重量％（元素換算値）担持し、乾燥後空気中で
６００℃まで段階的に焼成した後、水にバナジウム酸ア
ンモニウムとしゅう酸を加え、水浴上で加熱溶解させて
放冷した水溶液に投入し、３０分間浸漬し、シリカ・ア
ルミナ粉末に対してバナジウムを０．６重量％（金属元
素換算値）担持し、これを直径１．５ｍｍ、長さ２〜３
ｍｍのペレットにし、乾燥後空気中で６００℃まで段階
的に焼成し、銀、白金、Ｖ系触媒（第一の触媒）を調製
した。The present invention will be described in more detail by the following specific examples. Example 1 To 10 g of commercially available powdery silica-alumina (SiO 2 content 5% by weight, specific surface area 350 m 2 / g), an aqueous silver nitrate solution and an aqueous chloroplatinic acid solution were used, and 4% by weight of silver and 0. After loading 01% by weight (elemental conversion value), after drying and gradually calcining in air to 600 ° C., ammonium vanadate and oxalic acid were added to water, and the mixture was heated and dissolved in a water bath and allowed to stand for cooling. Then, soak for 30 minutes, and carry 0.6% by weight (metal element conversion value) of vanadium with respect to the silica / alumina powder, which has a diameter of 1.5 mm and a length of 2 to 3
mm pellets, dried and calcined stepwise in air to 600 ° C. to prepare silver, platinum, and V-based catalyst (first catalyst).
【００４１】次に、ペレット状チタニア（直径１．５ｍ
ｍ、長さ２〜３ｍｍ、比表面積３５ｍ2 ／ｇ）２ｇに塩
化白金酸水溶液を用いて白金を１重量％（元素換算値）
担持させたあと、水にバナジウム酸アンモニウムとしゅ
う酸を加え、水浴上で加熱溶解させて放冷した水溶液に
投入し、３０分間浸漬し、チタニアペレットに対してバ
ナジウムを３重量％（金属元素換算値）担持し、上記同
様に乾燥、焼成を行い、８０℃、１００℃、１２０℃で
各２時間乾燥し、そのあと、酸素２０％を含む窒素気流
下、１２０℃から５００℃まで５時間かけを昇温して、
Ｐｔ、Ｖ系浄化材（第二の触媒）を調製した。Next, pelletized titania (diameter 1.5 m
m, length 2 to 3 mm, specific surface area 35 m 2 / g) 2 g of chloroplatinic acid aqueous solution and 1% by weight of platinum (elemental conversion value)
After supporting it, ammonium vanadate and oxalic acid were added to water, and the mixture was heated and dissolved in a water bath, poured into an aqueous solution that had been allowed to cool, and immersed for 30 minutes. Vanadium was added to the titania pellets in an amount of 3% by weight (metal element conversion). Value) supported, dried and baked in the same manner as above, dried at 80 ° C., 100 ° C. and 120 ° C. for 2 hours each, and then in a nitrogen stream containing 20% oxygen for 5 hours from 120 ° C. to 500 ° C. To raise
A Pt, V-based purification material (second catalyst) was prepared.
【００４２】第一の触媒（銀、白金、Ｖ系触媒）約３．
６ｇ及び第二の触媒（Ｐｔ、Ｖ系触媒）約１．２ｇから
なる浄化材を、排ガスの流入側に銀、白金、Ｖ系触媒
が、また流出側にＰｔ、Ｖ系触媒がそれぞれ位置するよ
うに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、エタノール、プロ
ピレン、二酸化硫黄、窒素及び水分）を毎分４．４リッ
トル（標準状態）の流量で流して（第一の触媒の見かけ
空間速度は約３０，０００ｈ-1、第二の触媒の見かけ空
間速度は約１００，０００ｈ-1である。）、反応管内の
排ガス温度を２５０℃から６００℃まで５０℃ごとに変
化させ、それぞれの温度でエタノールと窒素酸化物とを
反応させた。First catalyst (silver, platinum, V-based catalyst) About 3.
A purifying agent composed of 6 g and about 1.2 g of the second catalyst (Pt, V-based catalyst), silver, platinum, and V-based catalysts are located on the inflow side of the exhaust gas, and Pt and V-based catalysts are on the outflow side. Was set in the reaction tube. Next, a gas having the composition shown in Table 1 (nitrogen monoxide, carbon monoxide, oxygen, ethanol, propylene, sulfur dioxide, nitrogen and water) was flowed at a flow rate of 4.4 liters per minute (standard state) (first). the apparent space velocity of one catalyst is about 30,000 h -1, apparent space velocity of the second catalyst is about 100,000h -1.), 50 per ° C. the exhaust gas temperature in the reaction tube to 600 ° C. from 250 ° C. And ethanol was reacted with nitrogen oxide at each temperature.
【００４３】 表１ 成分 濃度 一酸化窒素 800 ppm （乾燥ベース） 酸素 10 容量％ （乾燥ベース） 一酸化炭素 100 ppm （乾燥ベース） エタノール 一酸化窒素の３倍の質量（乾燥ベース） プロピレン 100 ppm （乾燥ベース） 二酸化硫黄 80 ppm （乾燥ベース） 窒素 残部 水分 10 容量％（上記成分の総体積に対して）Table 1 Component Concentration Nitric oxide 800 ppm (dry basis) Oxygen 10% by volume (dry basis) Carbon monoxide 100 ppm (dry basis) Ethanol 3 times the mass of nitric oxide (dry basis) Propylene 100 ppm ( Dry basis) Sulfur dioxide 80 ppm (dry basis) Nitrogen Residual water 10% by volume (based on total volume of the above ingredients)
【００４４】反応管通過後のガスの窒素酸化物（ＮＯ＋
ＮＯ2 ）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。また、一酸化炭
素、二酸化硫黄及び炭化水素（プロピレン）の濃度はそ
れぞれＣＯ計、ＳＯｘ計、ＨＣ計により測定し、一酸化
炭素、炭化水素の除去率及び二酸化硫黄の酸化率を求め
た。ただし、一酸化炭素、炭化水素の除去率は、エタノ
ールを添加しない条件で求めた。結果を表２に示す。Nitrogen oxide (NO +) of the gas after passing through the reaction tube
The concentration of NO 2 ) was measured by a chemiluminescence type nitrogen oxide analyzer to determine the nitrogen oxide removal rate. Further, the concentrations of carbon monoxide, sulfur dioxide and hydrocarbon (propylene) were measured with a CO meter, SOx meter and HC meter, respectively, and the carbon monoxide and hydrocarbon removal rates and the sulfur dioxide oxidation rate were determined. However, the removal rates of carbon monoxide and hydrocarbons were obtained under the condition that ethanol was not added. The results are shown in Table 2.
【００４５】実施例２ 実施例１と同様な方法で、粉末状シリカ・アルミナに硝
酸銀水溶液、塩化白金酸水溶液及びバナジウム酸アンモ
ニウム水溶液を用いて、銀を４重量％、白金を０．０１
重量％、バナジウムを０．６重量％（金属元素換算値）
担持させた触媒約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、長さ約１２．５ｍ
ｍ、４００セル／インチ2 ）にコートし、乾燥後６００
℃まで段階的に焼成し、銀、白金、Ｖ系浄化材（第一の
触媒をコートした浄化材）を調製した。 Example 2 In the same manner as in Example 1, silver silica aqueous solution, silver nitrate aqueous solution, chloroplatinic acid aqueous solution and ammonium vanadate aqueous solution were used in powdery silica / alumina to obtain 4% by weight of silver and 0.01% of platinum.
Wt%, vanadium 0.6 wt% (metal element conversion value)
About 1.0 g of the supported catalyst was put into a commercially available cordierite honeycomb molded body (diameter 30 mm, length about 12.5 m).
m, 400 cells / inch 2 ) and dried 600
The silver, platinum, and V-based purification material (purification material coated with the first catalyst) was prepared by firing in stages to 0 ° C.
【００４６】次に、チタニア粉末（比表面積５０ｍ2 ／
ｇ）に塩化白金酸水溶液を用いて白金を１重量％（チタ
ニア基準）担持させたあと、タングステン酸アンモニウ
ムパラ五水和物、しゅう酸に水を加えて水浴上で加熱し
て溶解させた水溶液に投入し、３０分間浸漬し、チタニ
アに対してタングステンを３重量％（金属元素換算値）
担持し、スラリー状にした。上記銀系浄化材と同様のハ
ニカム状成形体（直径３０ｍｍ、長さ約４．２ｍｍ）に
スラリーを０．４ｇ（乾燥ベース）コートした。実施例
１と同様の条件で乾燥、焼成を行い、Ｐｔ、Ｗ系浄化材
（第二の触媒をコートした浄化材）を調製した。Next, titania powder (specific surface area 50 m 2 /
An aqueous solution prepared by supporting 1% by weight of platinum (based on titania) with an aqueous solution of chloroplatinic acid (g) and then adding ammonium tungstate parapentahydrate and oxalic acid and heating them in a water bath to dissolve them. 3 minutes by weight of tungsten with respect to titania (metal element conversion value)
Supported and made into a slurry. 0.4 g (dry basis) of the slurry was coated on the same honeycomb-shaped molded body (diameter 30 mm, length about 4.2 mm) as the above silver-based purification material. Drying and firing were performed under the same conditions as in Example 1 to prepare a Pt, W-based purification material (purification material coated with the second catalyst).
【００４７】反応管内の排ガスの流入側に銀、白金、Ｖ
系浄化材、流出側にＰｔ、Ｗ系浄化材をそれぞれセット
し、表１に示す組成のガスで実施例１と同様に評価した
（銀、白金、Ｖ系浄化材の見かけ空間速度は約３０，０
００ｈ-1、Ｐｔ、Ｗ系浄化材の見かけ空間速度は約９
０，０００ｈ-1である。）。実験結果を表２に示す。On the inflow side of the exhaust gas in the reaction tube, silver, platinum, V
A system purification material and Pt and W purification materials were respectively set on the outflow side, and the gases having the compositions shown in Table 1 were evaluated in the same manner as in Example 1 (the apparent space velocity of the silver, platinum, and V purification materials was about 30). , 0
The apparent space velocity of the 00h -1 , Pt, W-based purification material is about 9
It is 10,000 h -1 . ). The experimental results are shown in Table 2.
【００４８】実施例３ 実施例２と同様な方法で、銀、白金、Ｖ系浄化材を調製
した。また、同様な方法で、粉末状チタニアに白金を１
重量％、タングステンを２重量％、バナジウムを１重量
％（それぞれ金属元素換算値）を担持した後、ハニカム
状成形体にコートしてＰｔ、Ｗ、Ｖ系浄化材を調製し
た。 Example 3 In the same manner as in Example 2, silver, platinum and V-based purification materials were prepared. In addition, platinum is added to powdered titania by the same method.
Wt%, 2 wt% of tungsten, and 1 wt% of vanadium (each converted to a metal element) were carried, and then coated on a honeycomb formed body to prepare a Pt, W, and V-based purification material.
【００４９】反応管内の排ガスの流入側に銀、白金、Ｖ
系浄化材、流出側にＰｔ、Ｗ、Ｖ系浄化材をそれぞれセ
ットし、表１に示す組成のガスで実施例１と同様に評価
した（銀、白金、Ｖ系浄化材の見かけ空間速度は約３
０，０００ｈ-1、Ｐｔ、Ｗ、Ｖ系浄化材の見かけ空間速
度は約９０，０００ｈ-1である。）。実験結果を表２に
示す。On the inflow side of the exhaust gas in the reaction tube, silver, platinum, V
A system purification material and Pt, W, and V purification materials were respectively set on the outflow side, and the gases having the compositions shown in Table 1 were evaluated in the same manner as in Example 1 (the apparent space velocities of silver, platinum, and V purification materials are About 3
0,000h -1, Pt, W, apparent space velocity V based purification material is about 90,000h -1. ). The experimental results are shown in Table 2.
【００５０】実施例４ 実施例２と同様な方法で、市販の粉末状アルミナ（比表
面積２００ｍ2 ／ｇ）に硝酸銀水溶液、塩化白金酸水溶
液及びバナジウム酸アンモニウム水溶液を用いて、銀を
４重量％、白金を０．０１重量％、バナジウムを０．６
重量％（金属元素換算値）担持させた触媒約１．０ｇ
を、市販のコージェライト製ハニカム状成形体（直径３
０ｍｍ、長さ約１２．５ｍｍ、４００セル／インチ2 ）
にコートし、乾燥後６００℃まで段階的に焼成し、銀、
白金、Ｖ系浄化材（第一の触媒をコートした浄化材）を
調製した。また、実施例２と同様な方法で、Ｐｔ、Ｗ系
浄化材（第二の触媒をコートした浄化材）を調製した。 Example 4 In the same manner as in Example 2, 4 wt% of silver was added to commercially available powdered alumina (specific surface area 200 m 2 / g) using an aqueous solution of silver nitrate, an aqueous solution of chloroplatinic acid and an aqueous solution of ammonium vanadate. 0.01% by weight of platinum and 0.6 of vanadium
Weight% (metal element conversion value) About 1.0g of supported catalyst
A commercially available cordierite honeycomb-shaped molded body (diameter 3
0 mm, length about 12.5 mm, 400 cells / inch 2 )
Coating, and after drying, calcining stepwise up to 600 ℃, silver,
A platinum / V-based purification material (purification material coated with the first catalyst) was prepared. In addition, a Pt, W-based purification material (purification material coated with the second catalyst) was prepared in the same manner as in Example 2.
【００５１】反応管内の排ガスの流入側に銀、白金、Ｖ
系浄化材、流出側にＰｔ、Ｗ系浄化材をそれぞれセット
し、表１に示す組成のガスで実施例２と同様に評価した
（銀、白金、Ｖ系浄化材の見かけ空間速度は約３０，０
００ｈ-1、Ｐｔ、Ｗ系浄化材の見かけ空間速度は約９
０，０００ｈ-1である。）。実験結果を表２に示す。Silver, platinum, V is provided on the inflow side of the exhaust gas in the reaction tube.
A system purification material and Pt and W purification materials were respectively set on the outflow side and evaluated with the gas having the composition shown in Table 1 in the same manner as in Example 2 (the apparent space velocity of the silver, platinum and V purification materials was about 30). , 0
The apparent space velocity of the 00h -1 , Pt, W-based purification material is about 9
It is 10,000 h -1 . ). The experimental results are shown in Table 2.
【００５２】比較例１ 実施例１と同様な方法で、ペレット状アルミナに銀を４
重量％担持して作成した銀系触媒３．６ｇを反応管にセ
ットし、表１に示す組成のガスを毎分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
３０，０００ｈ-1）、実施例１と同じ条件で評価した。
実験結果を合わせて表２に示す。 Comparative Example 1 By the same method as in Example 1, silver was added to pelletized alumina.
3.6 g of a silver-based catalyst prepared by supporting it by weight% was set in a reaction tube, and a gas having a composition shown in Table 1 was flowed at a flow rate of 4.4 liters per minute (standard state) (total apparent space velocity was about 30,000 h -1), were evaluated under the same conditions as in example 1.
The experimental results are also shown in Table 2.
【００５３】 表２ 窒素酸化物（ＮＯｘ）、一酸化炭素（ＣＯ）、炭化水素（ＨＣ）の除去率 及び二酸化硫黄（ＳＯ2 ）の酸化率 反応温度 除去成分 除去率（NOx 、CO、HC）及び酸化率（SO2 ）（％） （℃） 実施例１ 実施例２ 実施例３ 実施例４ 比較例１ ２５０ ＮＯｘ ３２ ３０ ３５ ３５ １２ ＣＯ ８２ ７７ ７２ ７８ １５ ＨＣ ５２ ４８ ５２ ４９ １０ ＳＯ2 − − − − − ３００ ＮＯｘ ６０ ５５ ６３ ５８ ３０ ＣＯ ９２ ９１ ９０ ９３ ４０ ＨＣ ６７ ６７ ７０ ６８ ３２ ＳＯ2 − − − − − ３５０ ＮＯｘ ８２ ７５ ８５ ７８ ５０ ＣＯ ９８ ９６ ９６ ９８ ６０ ＨＣ ７２ ７２ ７２ ７５ ３２ ＳＯ2 − − − − − ４００ ＮＯｘ ８０ ７８ ７８ ８０ ６０ ＣＯ １００ １００ １００ １００ ７０ ＨＣ ９５ ９５ ９５ ９６ ４０ ＳＯ2 ５ ５ ５ ５ − ４５０ ＮＯｘ ６８ ６８ ６５ ６５ ７０ ＣＯ １００ １００ １００ １００ ７０ ＨＣ ９８ ９８ ９６ ９９ ６５ ＳＯ2 ７ ７ ７ ７．２ − ５００ ＮＯｘ ５２ ５３ ５０ ５０ ６０ ＣＯ １００ １００ １００ １００ ８０ ＨＣ １００ １００ １００ １００ ７０ ＳＯ2 １２ １２ １２ １２．５ − ５５０ ＮＯｘ ３０ ３０ ３０ ２５ ５２ ＣＯ １００ １００ １００ １００ ９０ ＨＣ １００ １００ １００ １００ ８５ ＳＯ2 １５ １５ １５ １６ − ６００ ＮＯｘ １０ １０ １０ ８ ２０ ＣＯ １００ １００ １００ １００ ９８ ＨＣ １００ １００ １００ １００ ９０ ＳＯ2 ２０ ２０ ２０ ２１ − Table 2 Nitrogen oxide (NOx), carbon monoxide (CO), hydrocarbon (HC) removal rate and sulfur dioxide (SO 2 ) oxidation rate Reaction temperature Removal component removal rate (NOx, CO, HC) And oxidation rate (SO 2 ) (%) (° C.) Example 1 Example 2 Example 3 Example 4 Comparative Example 1 250 NOx 32 30 30 35 35 12 CO 82 77 72 72 78 15 HC 52 48 52 52 49 10 SO 2 − − − − − 300 NOx 60 55 63 63 58 30 CO 92 91 91 90 93 40 HC 67 67 70 70 68 32 SO 2 − − − − 350 NOx 82 75 75 85 78 50 CO 98 96 96 96 98 60 HC 72 72 72 72 75 32 32 SO 2 - - - - - 400 NOx 80 78 78 80 60 CO 100 100 100 100 70 HC 95 95 95 96 40 S 2 5 5 5 5 - 450 NOx 68 68 65 65 70 CO 100 100 100 100 70 HC 98 98 96 99 65 SO 2 7 7 7 7.2 - 500 NOx 52 53 50 50 60 CO 100 100 100 100 80 HC 100 100 100 100 70 SO 2 12 12 12 12.5-550 NOx 30 30 30 30 25 52 CO 100 100 100 100 100 90 HC 100 100 100 100 100 85 SO 2 15 15 15 15 16-600 NOx 10 10 10 10 8 20 CO 100 100 100 100 98 HC 100 100 100 100 90 SO 2 20 20 20 21 -
【００５４】表２に示すように、比較例１に比べて、実
施例１〜４が広い温度範囲で効果的な窒素酸化物除去を
示すとともに、低温領域でも高い一酸化炭素、炭化水素
の除去が得られた。さらに、多孔質無機酸化物にアルミ
ナ複合酸化物を用いることにより、二酸化硫黄の酸化特
性も低かった。As shown in Table 2, as compared with Comparative Example 1, Examples 1 to 4 show effective removal of nitrogen oxides over a wider temperature range, and higher removal of carbon monoxide and hydrocarbons even in a low temperature region. was gotten. Furthermore, the oxidation characteristics of sulfur dioxide were low by using the alumina composite oxide as the porous inorganic oxide.
【００５５】[0055]
【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.
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 35/02 ＺＡＢ Ｐ Ｂ０１Ｄ 53/36 １０４ Ａ Continuation of the front page (51) Int.Cl. 6 Identification number Office reference number FI technical display location B01J 35/02 ZAB P B01D 53/36 104 A
Claims (6)
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、残留及び未反応の一
酸化炭素及び炭化水素も酸化除去する排ガス浄化材にお
いて、（１）多孔質の無機酸化物に（ａ）前記無機酸化
物の０．２〜１５重量％（元素換算値）の銀及び／又は
銀化合物、又はそれらの混合物と、（ｂ）前記無機酸化
物の５重量％以下（元素換算値）のＷ、Ｖ、Ｍｎ、Ｍ
ｏ、Ｎｂ及びＴａからなる群より選ばれた少なくとも１
種の元素と、（ｃ）前記無機酸化物の１重量％以下（元
素換算値）のPt、Pd、Ru、Rh、Ir及びAuからなる群より
選ばれた少なくとも１種の元素とを担持してなる第一の
触媒と、（２）多孔質の無機酸化物に（ｄ）前記無機酸
化物の１０重量％以下（金属元素換算値）のＷ、Ｖ、Ｍ
ｎ、Ｍｏ、Ｎｂ及びＴａからなる群より選ばれた少なく
とも一種の元素の酸化物と、（ｅ）前記無機酸化物の５
重量％以下（元素換算値）のPt、Pd、Ru、Rh、Ir及びAu
からなる群より選ばれた少なくとも１種の元素とを担持
してなる第二の触媒とからなることを特徴とする排ガス
浄化材。1. Nitrogen oxides are reduced and removed from a combustion exhaust gas containing nitrogen oxides and oxygen in a larger amount than the theoretical reaction amount for coexisting unburned components, and residual and unreacted carbon monoxide and hydrocarbons are also oxidized. In the exhaust gas purifying material to be removed, (1) a porous inorganic oxide, and (a) 0.2 to 15% by weight of the inorganic oxide (elemental conversion value) of silver and / or a silver compound, or a mixture thereof. , (B) W, V, Mn, M of 5% by weight or less (elemental conversion value) of the inorganic oxide
at least 1 selected from the group consisting of o, Nb and Ta
And (c) at least one element selected from the group consisting of Pt, Pd, Ru, Rh, Ir, and Au in an amount of 1% by weight or less (elemental conversion value) of the inorganic oxide. And (2) a porous inorganic oxide, and (d) 10% by weight or less (metal element conversion value) of W, V, and M of the inorganic oxide.
an oxide of at least one element selected from the group consisting of n, Mo, Nb and Ta, and (e) 5 of the above inorganic oxide
Pt, Pd, Ru, Rh, Ir and Au of less than weight% (elemental conversion value)
An exhaust gas purification material, comprising a second catalyst carrying at least one element selected from the group consisting of:
て、前記浄化材の排ガス流入側に前記第一の触媒を有
し、排ガス流出側に前記第二の触媒を有することを特徴
とする排ガス浄化材。2. The exhaust gas purifying material according to claim 1, wherein the purifying material has the first catalyst on an exhaust gas inflow side and the second catalyst on an exhaust gas outflow side. Purifying material.
おいて、前記多孔質無機酸化物が、第一の触媒ではアル
ミナ単独、又はシリカ、チタニア及びジルコニアからな
る群より選ばれた少なくとも一種を含むアルミナ系複合
酸化物で、第二の触媒ではチタニア、アルミナ、ジルコ
ニア、シリカ及びそれらの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 or 2, wherein the porous inorganic oxide in the first catalyst is alumina alone or at least one selected from the group consisting of silica, titania and zirconia. An exhaust gas purification material comprising an alumina-based composite oxide containing titania, alumina, zirconia, silica and a composite oxide thereof as the second catalyst.
浄化材において、前記浄化材は前記第一及び第二の触媒
をセラッミクス製又は金属製の基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。4. The exhaust gas purifying material according to claim 1, wherein the purifying material is obtained by coating the surface of a ceramic or metal base with the first and second catalysts. Characteristic exhaust gas purification material.
浄化材において、前記第一及び第二の触媒の多孔質無機
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。5. The exhaust gas purifying material according to claim 1, wherein the porous inorganic oxides of the first and second catalysts are in the form of pellets or granules, respectively. Purifying material.
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、残留及び未反応の一
酸化炭素及び炭化水素も酸化除去する排ガス浄化方法に
おいて、請求項１〜５のいず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／又は炭素数２
以上の含酸素有機化合物、又はそれを含む燃料を添加し
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含酸素有機化合物との反
応により前記窒素酸化物を除去するとともに、残留及び
未反応の一酸化炭素及び炭化水素も酸化除去することを
特徴とする排ガス浄化方法。6. Nitrogen oxides are reduced and removed from a combustion exhaust gas containing nitrogen oxides and oxygen in a larger amount than the theoretical reaction amount for coexisting unburned components, and residual and unreacted carbon monoxide and hydrocarbons are also oxidized. In an exhaust gas purification method for removing, the exhaust gas purification material according to any one of claims 1 to 5 is used, the exhaust gas purification material is installed in the middle of an exhaust gas conduit, and hydrocarbons and / or carbon are provided upstream of the purification material. Number 2
Exhaust gas added with the oxygen-containing organic compound or the fuel containing the oxygen-containing organic compound is brought into contact with the purification material at 150 to 650 ° C., thereby removing the nitrogen oxides by reaction with the oxygen-containing organic compound in the exhaust gas. At the same time, residual and unreacted carbon monoxide and hydrocarbons are also removed by oxidation, and an exhaust gas purification method.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6092962A JPH07275709A (en) | 1994-04-06 | 1994-04-06 | Material and method for purifying exhaust gas |
| EP95300809A EP0667182A3 (en) | 1994-02-10 | 1995-02-09 | Exhaust gas cleaner and method for cleaning exhaust gas. |
| US08/444,050 US5670443A (en) | 1994-02-10 | 1995-05-18 | Exhaust gas cleaner and method for cleaning exhaust gas |
| US08/647,259 US5744112A (en) | 1994-02-10 | 1996-05-13 | Method for cleaning exhaust gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6092962A JPH07275709A (en) | 1994-04-06 | 1994-04-06 | Material and method for purifying exhaust gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07275709A true JPH07275709A (en) | 1995-10-24 |
Family
ID=14069064
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6092962A Pending JPH07275709A (en) | 1994-02-10 | 1994-04-06 | Material and method for purifying exhaust gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07275709A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015059904A1 (en) * | 2013-10-23 | 2015-04-30 | マツダ株式会社 | Exhaust gas purifying catalyst device and method for purifying exhaust gas |
| JP2015107479A (en) * | 2013-10-23 | 2015-06-11 | マツダ株式会社 | Exhaust gas purification catalyst device and exhaust gas purification method |
| JP2015137604A (en) * | 2014-01-23 | 2015-07-30 | マツダ株式会社 | Exhaust emission control catalyst device and exhaust emission control method |
| US9732648B2 (en) | 2013-10-23 | 2017-08-15 | Mazda Motor Corporation | Catalyst device for exhaust gas purification and method for exhaust gas purification |
-
1994
- 1994-04-06 JP JP6092962A patent/JPH07275709A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015059904A1 (en) * | 2013-10-23 | 2015-04-30 | マツダ株式会社 | Exhaust gas purifying catalyst device and method for purifying exhaust gas |
| JP2015107479A (en) * | 2013-10-23 | 2015-06-11 | マツダ株式会社 | Exhaust gas purification catalyst device and exhaust gas purification method |
| US9732648B2 (en) | 2013-10-23 | 2017-08-15 | Mazda Motor Corporation | Catalyst device for exhaust gas purification and method for exhaust gas purification |
| JP2015137604A (en) * | 2014-01-23 | 2015-07-30 | マツダ株式会社 | Exhaust emission control catalyst device and exhaust emission control method |
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