JPH0857263A - Exhaust gas purifying material and method therefor - Google Patents
Exhaust gas purifying material and method thereforInfo
- Publication number
- JPH0857263A JPH0857263A JP6218176A JP21817694A JPH0857263A JP H0857263 A JPH0857263 A JP H0857263A JP 6218176 A JP6218176 A JP 6218176A JP 21817694 A JP21817694 A JP 21817694A JP H0857263 A JPH0857263 A JP H0857263A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- purifying material
- catalyst
- oxide
- silver
- 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 98
- 238000000034 method Methods 0.000 title claims description 36
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims abstract description 219
- 239000003054 catalyst Substances 0.000 claims abstract description 117
- 239000007789 gas Substances 0.000 claims abstract description 96
- 229910052709 silver Inorganic materials 0.000 claims abstract description 46
- 239000004332 silver Substances 0.000 claims abstract description 46
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims abstract description 45
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 37
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 37
- 239000001301 oxygen Substances 0.000 claims abstract description 37
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 20
- 229910052751 metal Inorganic materials 0.000 claims abstract description 14
- 239000002184 metal Substances 0.000 claims abstract description 12
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 11
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 11
- 229910052737 gold Inorganic materials 0.000 claims abstract description 10
- 239000000203 mixture Substances 0.000 claims abstract description 10
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 9
- 229910052703 rhodium Inorganic materials 0.000 claims abstract description 9
- 229910052707 ruthenium Inorganic materials 0.000 claims abstract description 9
- 229910052741 iridium Inorganic materials 0.000 claims abstract description 8
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 6
- 229910052809 inorganic oxide Inorganic materials 0.000 claims description 51
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 43
- 229930195733 hydrocarbon Natural products 0.000 claims description 39
- 150000002430 hydrocarbons Chemical class 0.000 claims description 39
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 33
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 31
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 28
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 25
- 238000006243 chemical reaction Methods 0.000 claims description 20
- 239000002131 composite material Substances 0.000 claims description 19
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 16
- 150000002894 organic compounds Chemical class 0.000 claims description 16
- 239000000377 silicon dioxide Substances 0.000 claims description 14
- 239000000446 fuel Substances 0.000 claims description 11
- 239000000758 substrate Substances 0.000 claims description 7
- 229910021607 Silver chloride Inorganic materials 0.000 claims description 6
- 230000001590 oxidative effect Effects 0.000 claims description 6
- 229940100890 silver compound Drugs 0.000 claims description 6
- 150000003379 silver compounds Chemical class 0.000 claims description 6
- 239000008188 pellet Substances 0.000 claims description 5
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 claims description 5
- 229910000367 silver sulfate Inorganic materials 0.000 claims description 4
- 238000011144 upstream manufacturing Methods 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000003546 flue gas Substances 0.000 claims description 3
- 239000008187 granular material Substances 0.000 claims description 3
- YPNVIBVEFVRZPJ-UHFFFAOYSA-L silver sulfate Chemical compound [Ag+].[Ag+].[O-]S([O-])(=O)=O YPNVIBVEFVRZPJ-UHFFFAOYSA-L 0.000 claims description 3
- 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
- 229910000161 silver phosphate Inorganic materials 0.000 claims description 2
- FJOLTQXXWSRAIX-UHFFFAOYSA-K silver phosphate Chemical compound [Ag+].[Ag+].[Ag+].[O-]P([O-])([O-])=O FJOLTQXXWSRAIX-UHFFFAOYSA-K 0.000 claims description 2
- 229940019931 silver phosphate Drugs 0.000 claims description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 31
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 22
- 239000002585 base Substances 0.000 description 19
- 239000003638 chemical reducing agent Substances 0.000 description 15
- 238000000746 purification Methods 0.000 description 15
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 12
- 238000002485 combustion reaction Methods 0.000 description 12
- 229910021529 ammonia Inorganic materials 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 229910001868 water Inorganic materials 0.000 description 9
- 230000007423 decrease Effects 0.000 description 8
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 8
- 239000004215 Carbon black (E152) Substances 0.000 description 7
- 238000010304 firing Methods 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- 229910052815 sulfur oxide Inorganic materials 0.000 description 6
- -1 etc.) Inorganic materials 0.000 description 5
- 238000005470 impregnation Methods 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- 238000006722 reduction reaction Methods 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 4
- 239000012299 nitrogen atmosphere Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 229910001961 silver nitrate Inorganic materials 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- 125000004432 carbon atom Chemical group C* 0.000 description 3
- 238000010531 catalytic reduction reaction Methods 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
- 238000007254 oxidation 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
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 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
- 229910021536 Zeolite Inorganic materials 0.000 description 2
- 239000002253 acid Substances 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
- 239000012298 atmosphere Substances 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 229910052878 cordierite Inorganic materials 0.000 description 2
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000003350 kerosene Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 2
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 description 2
- 229910001923 silver oxide Inorganic materials 0.000 description 2
- 238000003980 solgel method Methods 0.000 description 2
- 239000010457 zeolite Substances 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 1
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 235000019270 ammonium chloride Nutrition 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910010293 ceramic material Inorganic materials 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
- TXKMVPPZCYKFAC-UHFFFAOYSA-N disulfur monoxide Inorganic materials O=S=S TXKMVPPZCYKFAC-UHFFFAOYSA-N 0.000 description 1
- 230000007613 environmental effect Effects 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
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- OTCVAHKKMMUFAY-UHFFFAOYSA-N oxosilver Chemical class [Ag]=O OTCVAHKKMMUFAY-UHFFFAOYSA-N 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000012629 purifying agent Substances 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 229910001958 silver carbonate Inorganic materials 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 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
素と、硫黄酸化物と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 purifying material for effectively removing nitrogen oxides from a combustion exhaust gas containing nitrogen oxides, excess oxygen, and sulfur oxides, 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 combustion exhaust gas discharged from internal combustion engines such as automobile engines, combustion equipment installed in factories, household fan heaters, and the like is excessive. It contains nitrogen oxides such as nitric oxide and nitrogen dioxide together with oxygen. Here, "containing excess oxygen" means that the exhaust gas contains more oxygen than the theoretical amount of oxygen necessary to burn unburned components such as carbon monoxide, hydrogen, and hydrocarbons. I do. In the following, nitrogen oxide 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。[0003] This nitrogen oxide is one of the causes of acid rain and is a major environmental problem. Therefore, various methods for removing nitrogen oxides in exhaust gas discharged from various combustion equipments are being 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。[0004] As a method for removing nitrogen oxides from a combustion exhaust gas containing excess oxygen, a selective catalytic reduction method using ammonia is used particularly for a large-scale fixed combustion device (a large-scale combustor in a factory or the like). 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. Therefore, the nitrogen oxides in the exhaust gas must be removed so that unreacted ammonia is not discharged. There are problems that the amount of injected ammonia must be controlled while measuring the concentration, and that the apparatus generally becomes 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。As another method, there is a non-selective catalytic reduction method in which a nitrogen oxide is reduced by using a gas such as hydrogen, carbon monoxide, or a hydrocarbon as a reducing agent. In order to reduce and remove nitrogen oxides, it is necessary to add a reducing agent in an amount equal to or more than a theoretical reaction amount with oxygen in exhaust gas, and there is a disadvantage that a large amount of the reducing agent is consumed. For this reason, the non-selective catalytic reduction method is practically effective only for exhaust gas having a low residual oxygen concentration burned near the stoichiometric air-fuel ratio, and is not practical because of poor versatility.
【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、「触媒」vol.33 No.2 、59ページ、199
1年等) 。In view of the above, a method has been proposed for removing nitrogen oxides by using a zeolite or a catalyst supporting a transition metal on the zeolite and adding a reducing agent having a theoretical reaction amount or less with oxygen in the exhaust gas (for example, Japanese Patent Application Laid-Open Publication No. H11-163873). No.63-100919, 63-28372
No. 7, JP-A No. 1-130735 and the 59th Annual Meeting of the Chemical Society of Japan
(1990) 2A526, `` Catalyst '' vol.33 No.2, p.59, 199
1 year).
【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（特開平６−１４２５２３号）。しかし、硫黄
酸化物の存在する排ガスでは、触媒成分のシンダリング
が起こりやすくなり、触媒活性種の表面積が低下し、窒
素酸化物の除去率が低下することが分かった。However, it has been found that in these methods, the temperature range for removing nitrogen oxides is narrow, and in the case of exhaust gas containing water, the removal rate of nitrogen oxides is significantly reduced. Therefore, the present inventors have provided a silver-based catalyst on the inflow side of the exhaust gas and a platinum-based catalyst on the outflow side. A purifying material that can also remove hydrocarbons has been previously proposed (JP-A-6-142523). However, it has been found that in the exhaust gas containing sulfur oxides, the scintillation of the catalyst component easily occurs, the surface area of the catalytically active species decreases, and the nitrogen oxide removal rate decreases.
【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及び硫黄酸化物を含有する燃
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。Accordingly, it is an object of the present invention to provide a method for producing nitrogen oxides, carbon monoxide, hydrogen, hydrocarbons and the like, such as combustion exhaust gas from a fixed combustion device and a gasoline engine, a diesel engine or the like, which burns under oxygen excess conditions. Exhaust gas that can efficiently remove nitrogen oxides from combustion exhaust gas containing oxygen and sulfur oxides in excess of the theoretical reaction amount with respect to unburned components, and can also oxidize and remove residual and unreacted carbon monoxide and hydrocarbons An object of the present invention is to provide a purification material and an exhaust gas purification method.
【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、特定量のシリカ等の無機酸化物を
含有するアルミナ複合無機酸化物に銀成分を担持してな
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Ｗ系成分担持
してなる触媒と、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
炭化水素と炭素数２以上の含酸素有機化合物のいずれか
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、硫黄酸化物
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。Means for Solving the Problems In view of the above problems, as a result of intensive studies, the present inventor has found that a catalyst comprising a silver component supported on an alumina composite inorganic oxide containing a specific amount of an inorganic oxide such as silica. It has been found that an organic compound such as ethanol reacts with an exhaust gas containing oxygen and nitrogen oxides to reduce nitrogen oxides to nitrogen gas and to produce ammonia as a by-product. Using an exhaust gas purifying material formed by combining the above silver-based catalyst, a catalyst carrying a W-based component capable of reducing nitrogen oxides with ammonia as a reducing agent, and a catalyst carrying a platinum-based component, If any of the hydrocarbons and oxygen-containing organic compounds having 2 or more carbon atoms or a fuel containing them is added, and the exhaust gas is brought into contact with the purifying material at a specific temperature and space velocity, sulfur oxides are contained. The present inventors have found that nitrogen oxides can be effectively removed from exhaust gas in a wide temperature range, 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、多孔質の無機酸化物に前記無機酸化物
の０．２〜１５重量％（銀元素換算値）の銀及び／又は
銀化合物、又はそれらの混合物を担持してなる第一の触
媒と、多孔質の無機酸化物に前記無機酸化物の０．５〜
３０重量％（金属元素換算値）のＷ、Ｖ、Ｍｏ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を担持し
てなる第二の触媒と、多孔質の無機酸化物に前記無機酸
化物の５重量％以下（金属元素換算値）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三の触媒とからなることを特徴
とする。That is, while reducing and removing nitrogen oxides from a flue gas containing nitrogen oxides and oxygen in excess of the theoretical reaction amount for coexisting unburned components, residual and unreacted carbon monoxide and hydrocarbons are also oxidized. The exhaust gas purifying material of the present invention to be removed has a porous inorganic oxide carrying 0.2 to 15% by weight (in terms of silver element) of silver and / or a silver compound of the inorganic oxide or a mixture thereof. The first catalyst, the porous inorganic oxide to the inorganic oxide 0.5 ~
A second catalyst supporting 30% by weight (in terms of metal element) of an oxide of at least one element selected from the group consisting of W, V, and Mo; Of Pt, Pd, Ru,
And a third catalyst supporting at least one element selected from the group consisting of Rh, 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、１５０〜６００℃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。In addition, nitrogen oxides are reduced and removed from a combustion exhaust gas containing nitrogen oxides and oxygen in excess of the theoretical reaction amount for coexisting unburned components, and residual and unreacted carbon monoxide and hydrocarbons are also oxidized. In the exhaust gas purifying method of the present invention, the exhaust gas purifying material is provided in the middle of an exhaust gas conduit, the exhaust gas purifying material is provided in the middle of the exhaust gas conduit, and the hydrocarbon and / or carbon number is upstream of the purifying material. 2
The oxygen-containing organic compound or the exhaust gas to which the fuel containing it is added is brought into contact with the purifying material at 150 to 600 ° C., thereby removing the nitrogen oxides by the reaction with the oxygen-containing organic compound in the exhaust gas. In addition, residual and unreacted carbon monoxide and hydrocarbons are oxidized and removed.
【００１３】以下、本発明を詳細に説明する。本発明で
は、多孔質の無機酸化物に前記無機酸化物の０．２〜１
５重量％（銀元素換算値）の銀及び／又は銀化合物、又
はそれらの混合物を担持してなる第一の触媒と、多孔質
の無機酸化物に前記無機酸化物の０．５〜３０重量％
（金属元素換算値）のＷ、Ｖ、Ｍｏ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を担持してなる第二
の触媒と、多孔質の無機酸化物に前記無機酸化物の５重
量％以下（金属元素換算値）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
持してなる第三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
素と炭素数２以上の含酸素有機化合物のいずれか又はそ
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、第二の触媒及び第三の触媒を組み合わ
せて用いるが、排ガス流入側から流出側へ順に第一の触
媒、第二の触媒、第三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。Hereinafter, the present invention will be described in detail. In the present invention, the porous inorganic oxide may contain the inorganic oxide in an amount of 0.2 to 1%.
5% by weight (in terms of silver element) of a first catalyst supporting silver and / or a silver compound or a mixture thereof, and 0.5 to 30% by weight of the inorganic oxide on a porous inorganic oxide %
A second catalyst supporting an oxide of at least one element selected from the group consisting of W, V, and Mo (in terms of metal elements); Pt, Pd, Ru, Rh, Ir and
An exhaust gas purifying material comprising a third catalyst carrying at least one element selected from the group consisting of Au is installed in an exhaust gas conduit, and hydrocarbons and carbon are located upstream of the purifying material installation position. Exhaust gas to which any one of several or more oxygen-containing organic compounds or a fuel containing the same is added is brought into contact with the purifying material to reduce and remove nitrogen oxides in the exhaust gas. In the present invention, the first catalyst, the second catalyst, and the third catalyst are used in combination, but the first catalyst, the second catalyst, and the third catalyst are arranged in order from the exhaust gas inflow side to the outflow side. Is preferred.
With this arrangement, 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、第二及び第三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 embodiment of the exhaust gas purifying material of the present invention, first, second and third catalysts each comprising a powdery porous inorganic oxide carrying a catalytically active species are provided on a purifying material substrate. A purifying material formed by coating a purifying material substrate with a coated purifying material or a powdery porous inorganic oxide and then carrying a catalytically active species. As a ceramic material forming the base of the purifying material, γ-alumina and its composite oxide (γ
-Alumina-titania, γ-alumina-silica, γ-alumina-zirconia, etc.), zirconia, titania-zirconia, and other heat-resistant porous materials having a large surface area. When high heat resistance is required, it is preferable to use cordierite, mullite, alumina, a composite thereof, and the like. In addition, a known metal material can be used for the base 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、第二の触媒及び第三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
Various changes can be made according to the purpose. In addition, the base body is the entrance part,
Two or more parts such as an outlet part can be used in combination. Examples of the structure of the substrate include a honeycomb structure type, a foam type, a three-dimensional network structure type formed of a fibrous refractory, a granular shape, a pellet shape, and the like. The first catalyst, the second catalyst, and the third catalyst may be coated on different positions on the same substrate, or may be coated on different substrates and 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てなる触媒、又は触媒活性種を
担持した粉末状多孔質無機酸化物をペレット状又は顆粒
状に成形したもの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 catalyst comprising a porous inorganic oxide in the form of pellets, granules or powder carrying a catalytically active species, or a powder comprising a catalytically active species. It is a purifying material obtained by molding a porous inorganic oxide into pellets or granules into a casing having a desired shape.
【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及び／又は銀化合
物、又はそれらの混合物を担持してなり、排ガスの流入
側に形成される。銀化合物は銀の酸化物、塩化銀、硫酸
銀及び燐酸銀などからなる群より選ばれた少なくとも一
種であり、好ましくは銀の酸化物、塩化銀又は硫酸銀、
更に好ましくは銀の酸化物又は塩化銀である。The following three catalysts are formed in the purifying material of the present invention. (1) First Catalyst The first catalyst is formed by supporting silver and / or a silver compound or a mixture thereof on a porous inorganic oxide, and is formed on the exhaust gas inflow side. The silver compound is at least one selected from the group consisting of oxides of silver, silver chloride, silver sulfate, silver phosphate, and the like, preferably silver oxides, silver chloride or silver sulfate,
More preferably, silver oxide or silver chloride is used.
【００１８】多孔質の無機酸化物としては、アルミナ単
独、又は多孔質のシリカ、チタニア、ジルコニアからな
る群より選ばれた少なくとも一種以上の酸化物と、アル
ミナとからなるアルミナ複合酸化物等を使用することが
できるが、好ましくはアルミナとシリカからなる複合酸
化物を用いる。アルミナ複合酸化物、特にアルミナ・シ
リカ複合酸化物を用いることにより、硫黄酸化物の存在
下で、７００℃のような高い排ガス温度でも、浄化材の
表面積低下や、触媒活性種のシンダリングが起こりにく
くなり、浄化材の耐熱性、耐久性が向上する。As the porous inorganic oxide, alumina alone, or an alumina composite oxide comprising alumina and at least one oxide selected from the group consisting of porous silica, titania and zirconia, and the like are used. Preferably, a composite oxide composed of alumina and silica is used. By using an alumina composite oxide, particularly an alumina-silica composite oxide, even in a high exhaust gas temperature such as 700 ° C. in the presence of a sulfur oxide, a reduction in the surface area of the purifying material and the sintering of the catalytically active species hardly occur. As a result, the heat resistance and durability of the purification material are improved.
【００１９】アルミナ複合酸化物はアルミナ・シリカ複
合酸化物などの市販品、又はアルミナにシリカゾルなど
の無機酸化物ゾルを混合して複合化させたものや、ゾル
−ゲル法によって調製して得られるものを用いる。アル
ミナ複合酸化物におけるアルミナ以外の成分の含有量は
５０重量％以下であり、好ましくは０．１〜４０重量％
である。アルミナ以外の成分の含有量が０．１重量％未
満では、硫黄酸化物の存在下で長時間反応させると窒素
酸化物の除去率が低下し、５０重量％を越えると、反応
初期から全温度範囲における窒素酸化物の除去率が低下
する。The alumina composite oxide is a commercially available product such as an alumina-silica composite oxide, a composite obtained by mixing alumina with an inorganic oxide sol such as a silica sol, or prepared by a sol-gel method. Use something. The content of components other than alumina in the alumina composite oxide is 50% by weight or less, and preferably 0.1 to 40% by weight.
It is. When the content of components other than alumina is less than 0.1% by weight, the removal rate of nitrogen oxides is reduced when the reaction is carried out for a long time in the presence of sulfur oxides. The nitrogen oxide removal rate in the range is reduced.
【００２０】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 for the first catalyst is preferably 10 m 2 / g or more. If 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 carried thereon) becomes small, and good nitrogen oxides cannot be removed. More preferably, the specific surface area of the porous inorganic oxide is 30 m.
2 / g or more.
【００２１】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、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１００重量％に
対して０．２〜１５重量％（銀元素換算値）とする。
０．２重量％未満では窒素酸化物の除去率が低下する。
また、１５重量％を超す量の銀を担持すると含酸素有機
化合物自身の燃焼が起きやすく、窒素酸化物の除去率は
かえって低下する。好ましい銀成分の担持量は０．５〜
１２重量％である。The amount of the silver component supported as an active species on the inorganic oxide such as γ-alumina varies somewhat depending on the type of the organic compound and the fuel added to the exhaust gas, the contact time with the exhaust gas, and the like. The content is 0.2 to 15% by weight (in terms of silver element) based on 100% by weight of the inorganic oxide.
If the amount is less than 0.2% by weight, the removal rate of nitrogen oxides decreases.
In addition, when the silver content exceeds 15% by weight, the oxygen-containing organic compound itself tends to burn, and the nitrogen oxide removal rate is rather lowered. The preferred amount of the silver component is 0.5 to
It is 12% by weight.
【００２２】多孔質無機酸化物に担持された銀成分は粒
状を呈しているが、本発明の浄化材では、銀成分の粒子
の平均直径が１０〜１０００ｎｍとする。一般的には、
銀成分の粒子径が小さいほど、反応特性が高いが、平均
粒径が１０ｎｍ未満であると、還元剤である炭化水素及
び／又は含酸素有機化合物の酸化反応のみが進み、窒素
酸化物の除去率が低下する。一方、平均粒径が１０００
ｎｍを越えると、銀成分の反応特性が低減し、窒素酸化
物の除去率が下がる。好ましい平均粒径は１０〜５００
ｎｍ、更に好ましくは１０〜２００ｎｍとする。なお、
ここで言う平均とは算術平均のことを意味する。The silver component carried on the porous inorganic oxide is granular, but in the purifying material of the present invention, the silver component particles have an average diameter of 10 to 1000 nm. In general,
The smaller the particle diameter of the silver component, the higher the reaction characteristics. However, if the average particle diameter is less than 10 nm, only the oxidation reaction of the hydrocarbon and / or the oxygen-containing organic compound as the reducing agent proceeds to remove nitrogen oxides. The rate drops. On the other hand, when the average particle size is 1000
If it exceeds nm, the reaction characteristics of the silver component are reduced, and the nitrogen oxide removal rate is reduced. Preferred average particle size is 10 to 500
nm, more preferably 10 to 200 nm. In addition,
The average here means an arithmetic average.
【００２３】アルミナ等の無機酸化物に銀を担持する方
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。含浸法を用いる際、硝酸銀のような硝酸塩、塩化
物、硫酸塩、炭酸塩等の水溶液に多孔質無機酸化物を浸
漬する。沈澱法では硝酸銀とハロゲン化アンモニウムと
を反応させて、ハロゲン化銀として多孔質無機酸化物に
沈澱させる。これを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３００〜６５０℃で酸化
処理するのが好ましい。As a method of supporting silver on an inorganic oxide such as alumina, a known impregnation method, precipitation method, or the like can be used. When using the impregnation method, the porous inorganic oxide is immersed in an aqueous solution of a nitrate such as silver nitrate, chloride, sulfate, carbonate or the like. In the precipitation method, silver nitrate and ammonium halide are reacted to precipitate silver halide on a porous inorganic oxide. After drying at 50 to 150 ° C., particularly at about 70 ° C., it is preferable to raise the temperature stepwise at 100 to 600 ° C. for firing. The firing is preferably performed in an oxygen atmosphere, a nitrogen atmosphere, or a hydrogen gas flow. In the case of performing in a nitrogen atmosphere or a flow of hydrogen gas, it is preferable to perform the oxidation treatment at 300 to 650 ° C. at last.
【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 purifying material, the thickness of the first catalyst provided on the purifying material base is generally limited by the difference in thermal expansion characteristics between the base material and this catalyst. Often. The thickness of the catalyst provided on the purifying material base is preferably 300 μm or less. With such a thickness, it is possible to prevent the purifying material from being damaged by thermal shock or the like during use. A method for forming a catalyst on the surface of the purifying material base is performed by a known wash coat method, a 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。The amount of the first catalyst provided on the surface of the purifying material base is preferably 20 to 300 g / liter of the purifying material base. If the amount of the catalyst is less than 20 g / liter, good NOx removal cannot be performed. On the other hand, when the amount of the catalyst is 300
When the amount exceeds g / liter, the removal characteristics do not increase so much.
Pressure loss increases. More preferably, the first catalyst provided on the surface of the purifying material base is 50 to 250
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
Ｗ、Ｖ、Ｍｏからなる群より選ばれた少なくとも一種の
元素の酸化物を担持してなる。多孔質無機酸化物として
は、チタニア単独、又は他の多孔質無機酸化物を含むチ
タニア複合無機酸化物が挙げられる。好ましくはチタニ
ア単独、又はアルミナ、シリカ、ジルコニアからなる群
より選ばれた一種以上の酸化物を含有するチタニア複合
酸化物を用いる。チタニア複合酸化物を用いる場合、チ
タニア以外の成分の含有量は５０重量％以下とし、好ま
しくは０．１〜４０重量％とする。(2) Second Catalyst The second catalyst comprises a porous inorganic oxide carrying an oxide of at least one element selected from the group consisting of W, V, and Mo, which are catalytically active species. Become. Examples of the porous inorganic oxide include titania alone or a titania composite inorganic oxide containing another porous inorganic oxide. Preferably, titania alone or a titania composite oxide containing one or more oxides selected from the group consisting of alumina, silica, and zirconia is used. When using a titania composite oxide, the content of components other than titania is set to 50% by weight or less, preferably 0.1 to 40% by weight.
【００２７】Ｗ、Ｖ、Ｍｏのうち、Ｗ及び／又はＶを用
いるのが好ましい。第二の触媒で無機酸化物に担持する
Ｗ系酸化物の量は、上述の多孔質の無機酸化物を基準
（１００重量％）として０．５〜３０重量％（金属元素
換算値）とし、好ましくは１〜２０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、３０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。It is preferable to use W and / or V among W, V and Mo. The amount of the W-based oxide supported on the inorganic oxide by the second catalyst is 0.5 to 30% by weight (in terms of a metal element) based on the above-mentioned porous inorganic oxide (100% by weight), Preferably, it is 1 to 20% by weight (value in terms of metal element). Even if the amount of the W-based oxide exceeds 30% by weight based on the weight of the inorganic oxide, the effect is not changed. By using a W-based oxide, it is possible to remove nitrogen oxides using ammonia as a reducing agent. In the present invention, any catalyst that promotes the reduction reaction of nitrogen oxides by ammonia can be used without being limited to W-based oxides.
【００２８】第二の触媒におけるＷ系酸化物を担持する
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、しゅう酸塩等の水溶液に多孔質無機酸化物
を浸漬し、５０〜１５０℃、特に７０℃で乾燥後、１０
０〜６００℃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。As a method for supporting the W-based oxide in the second catalyst, known impregnation methods, precipitation methods, sol-gel methods,
A powder method or the like can be used. At that time, the porous inorganic oxide is immersed in an aqueous solution of an ammonium salt, an oxalate or the like of each element, dried at 50 to 150 ° C., particularly 70 ° C., and then dried.
It is carried out by raising the temperature stepwise at 0 to 600 ° C. and firing. This firing is performed in air, under an oxygen atmosphere, under a nitrogen atmosphere, or under a hydrogen gas flow. When firing is performed under a nitrogen atmosphere or a hydrogen gas flow, it is effective to perform an oxidation treatment at 300 to 650 ° C. at last. .
【００２９】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、Ｖ及び／又はＭｏ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、Ｖ及び／又は
Ｍｏ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 purifying material, the thickness of the second catalyst provided on the purifying material base is 300 μm.
m or less. The amount of the second catalyst provided on the surface of the purifying material base is 20 to 300 g / p of the purifying material base.
It is preferably liter. When the purifying material base is made of a porous inorganic oxide such as titania, a predetermined amount of an oxide of W, V and / or Mo can be carried thereon and used as a purifying agent. In addition, a porous inorganic oxide such as titania carrying a predetermined amount of an oxide of W, V and / or Mo can be used after being formed into a formed body such as a honeycomb.
【００３０】（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である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を担持してなる。多孔質無機酸
化物としては、アルミナ、チタニア、ジルコニア及びシ
リカからなる群より選ばれた少なくとも一種の酸化物な
ど、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−アルミナを用いる。(3) Third catalyst The third catalyst comprises a porous inorganic oxide and a catalytically active species of 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 oxide include a heat-resistant ceramic having a large surface area, such as at least one oxide selected from the group consisting of alumina, titania, zirconia, and silica. Preferably, γ-alumina is used.
【００３１】Pt、Pd、Ru、Rh、Ir及びAuのうち、Pt、P
d、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。P
t、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（金属
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０．０１〜４重量％である。Of Pt, Pd, Ru, Rh, Ir and Au, Pt, P
It is preferable to use at least one of d, Ru, Rh and Au, and particularly preferable to use at least one of Pt, Pd and Au. P
The loading amount of at least one of t, Pd, Ru, Rh, Ir, and Au is set to 5% by weight or less (in terms of a metal element) based on 100% by weight of the inorganic oxide. If the supported amount exceeds 5% by weight of the inorganic oxide, the removal effect of the silver component is greatly reduced. In addition, it is preferable to set the lower limit of the supported amount to 0.01% by weight. A more preferred loading is from 0.01 to 4% by weight.
【００３２】また、第三の触媒の活性種として、さら
に、アルカリ金属元素、アルカリ土類金属元素、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。これらの元素を担持す
ることにより、白金系の触媒の耐熱性を向上させること
ができる。It is preferable that at least one element selected from the group consisting of an alkali metal element, an alkaline earth metal element and a rare earth element is supported by 10% by weight or less as an active species of the third catalyst. By supporting these elements, the heat resistance of the platinum-based catalyst can be improved.
【００３３】第三の触媒における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、塩化物、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。As a method for supporting one or more of Pt, Pd, Ru, Rh, Ir and Au in the third catalyst, a known impregnation method, precipitation method and the like can be used. When using the impregnation method, the porous inorganic oxide is immersed in an aqueous solution of a carbonate, chloride, nitrate, acetate, hydroxide, or the like of a catalytically active species element,
After drying at 70 ° C., the temperature is raised stepwise at 100 to 700 ° C. and firing is performed.
【００３４】なお、上記浄化材の第一の好ましい形態で
は、浄化材基体上に設ける第三の触媒の厚さを３００μ
ｍ以下とするのがよい。また、浄化材基体の表面上に設
ける第三の触媒の量は、浄化材基体の２０〜３００ｇ／
リットルとするのが好ましい。In the first preferred embodiment of the purifying material, the thickness of the third catalyst provided on the purifying material base is 300 μm.
m or less. Further, the amount of the third catalyst provided on the surface of the purification material base is 20 to 300 g / p of the purification material base.
It is preferably liter.
【００３５】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、１０：１〜１：５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、１５０〜６００℃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１０：１を超
え、第二の触媒が少ないと、残留一酸化炭素、炭化水
素、アンモニアの酸化除去率が低下する。より好ましい
第一触媒と第二触媒の重量比は５：１〜１：４である。In the present invention, the weight ratio of the first catalyst to the second catalyst (the ratio of the total weight of the porous inorganic oxide to the catalytically active species) is from 10: 1 to 1: 5. Is preferred. The ratio is less than 1: 5 (less first catalyst)
As a result, the purification rate of nitrogen oxides as a whole decreases over a wide temperature range of 150 to 600 ° C. On the other hand, when the ratio exceeds 10: 1 and the amount of the second catalyst is small, the oxidative removal rates of residual carbon monoxide, hydrocarbons, and ammonia decrease. A more preferred weight ratio of the first catalyst to the second catalyst is 5: 1 to 1: 4.
【００３６】一方、第一の触媒と、第三の触媒との重量
比（多孔質無機酸化物と触媒活性種との合計重量の比）
は、２０：１〜１：５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、１５０〜６０
０℃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２０：１を超え、第三の触媒が少
ないと、炭化水素、一酸化炭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１５：１
〜１：１である。On the other hand, the weight ratio of the first catalyst to the third catalyst (ratio of the total weight of the porous inorganic oxide and the catalytically active species)
Is preferably 20: 1 to 1: 5. The ratio is 1:
If it is less than 5 (the amount of the first catalyst is small), 150 to 60
In a wide temperature range of 0 ° C., the purification rate of nitrogen oxides is reduced overall. On the other hand, if the ratio exceeds 20: 1 and the amount of the third catalyst is small, the removal rate of hydrocarbons and carbon monoxide decreases. More preferably, the weight ratio of the first catalyst to the third catalyst is 15: 1.
１1: 1.
【００３７】上述した構成の浄化材を用いれば、１５０
〜６００℃の広い温度領域において、硫黄酸化物を含む
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-described structure is used, 150
In a wide temperature range of up to 600 ° C., good removal of nitrogen oxides can be performed even with exhaust gas containing sulfur oxides.
【００３８】次に、本発明の方法について説明する。ま
ず、第一の触媒、第二の触媒及び第三の触媒を有する排
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三の触
媒の間にあるように配置する。Next, the method of the present invention will be described. First, an exhaust gas purifying material having a first catalyst, a second catalyst, and a third catalyst is provided in the middle of an exhaust gas conduit. Preferably, 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 third catalyst.
【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。Although the exhaust gas contains ethylene, propylene and the like to some extent as residual hydrocarbons, it is generally not enough to reduce NOx in the exhaust gas. The above oxygen-containing organic compound or a reducing agent comprising a mixed fuel containing them is introduced into exhaust gas. The position where the reducing agent is introduced is upstream of the position where the purifying 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。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 hydrocarbons introduced from the outside, gaseous or liquid alkanes, alkenes and / or alkynes can be used under standard conditions. As the gaseous hydrocarbon in the standard state, an alkane, alkene or alkyne having 2 or more carbon atoms is preferable. Specific examples of the hydrocarbon in a liquid state in a 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.
【００４１】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 fuels containing them can be used. The amount of the reducing agent introduced from the outside is determined by the weight ratio (weight of the reducing agent to be added / nitrogen oxide (N
O) is preferably from 0.1 to 5. If the weight ratio is less than 0.1, the removal rate of nitrogen oxides does not increase. On the other hand, if the weight ratio exceeds 5,
This leads to poor fuel economy.
【００４２】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 such that the weight ratio (the weight of the reducing agent to be added / the weight of the nitrogen oxide in the exhaust gas) is 0.1 to 5 in the same manner as described above.
【００４３】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、第一の触媒（銀系触媒）における
空間速度は 150,000ｈ-1以下、好ましくは 100,000ｈ-1
以下とする。第一の触媒の空間速度が 150,000ｈ-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。第二の触媒（Ｗ系触媒）に
おける空間速度は 200,000ｈ-1以下、好ましくは 150,0
00ｈ-1以下とする。第二の触媒の空間速度が 200,000ｈ
-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。第三の触媒（白金系触媒）における空間
速度は 200,000ｈ-1以下、好ましくは 150,000ｈ-1以下
とする。第三の触媒の空間速度が 200,000ｈ-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。In the present invention, the space velocity of the first catalyst (silver-based catalyst) is 150,000 h -1 in order to efficiently reduce and remove nitrogen oxides with an oxygen-containing organic compound, hydrocarbon or ammonia. Or less, preferably 100,000h -1
The following is assumed. When the space velocity of the first catalyst exceeds 150,000 h -1 , the reduction reaction of nitrogen oxides does not sufficiently occur, and the nitrogen oxide removal rate decreases. The space velocity of the second catalyst (W-based catalyst) is 200,000 h -1 or less, preferably 150,0 h
00h -1 or less. Space velocity of the second catalyst is 200,000h
If it exceeds -1 , the oxidizing and removing properties of hydrocarbons, carbon monoxide, etc., deteriorate. The space velocity in the third catalyst (platinum catalyst) is 200,000 -1 or less, preferably 150,000H -1 or less. When the space velocity of the third catalyst exceeds 200,000 h -1 , the oxidizing and removing properties of hydrocarbons, carbon monoxide and the like deteriorate.
【００４４】また、本発明では、含酸素有機化合物と窒
素酸化物とが反応する部位である浄化材設置部位におけ
る排ガスの温度を１５０〜６００℃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、６００℃を超す温度とすると、含酸素有機
化合物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 is maintained at 150 to 600 ° C. at the purification material installation site where the oxygen-containing organic compound reacts with the nitrogen oxide. If the temperature of the exhaust gas is lower than 150 ° C., the reaction between the reducing agent and the nitrogen oxide does not proceed, and it is not possible to remove the nitrogen oxide satisfactorily. On the other hand, when the temperature exceeds 600 ° C., the combustion of the oxygen-containing organic compound itself takes precedence, and the reduction and removal rate of nitrogen oxides decreases. The preferred exhaust gas temperature is between 250 and 600C.
【００４５】[0045]
【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・アルミナ複合酸化物（シリカ含有
量５重量％、比表面積３５０ｍ2 ／ｇ）１０ｇに、硝酸
銀水溶液を用いてシリカ・アルミナに対して４重量％
（銀元素換算値）の銀を担持し、乾燥後、空気中で段階
的に６００℃まで焼成し、これを直径１．５ｍｍ、長さ
２〜３ｍｍのペレットに成形して、銀系触媒（第一の触
媒）を調製した。The present invention will be described in more detail with reference to the following specific examples. Example 1 To 10 g of a commercially available powdered silica-alumina composite oxide (silica content: 5% by weight, specific surface area: 350 m 2 / g), 4% by weight based on silica-alumina using an aqueous silver nitrate solution
After carrying silver (in terms of silver element), drying, and calcination in air in a stepwise manner to 600 ° C., this is formed into pellets having a diameter of 1.5 mm and a length of 2 to 3 mm, and a silver catalyst ( First catalyst) was prepared.
【００４６】次に、タングステン酸アンモニウムパラ五
水和物１．８ｇ、しゅう酸１．０ｇに水６．２mlを加
え、水浴上で加熱して溶解させた後、冷却した水溶液
に、チタニア（粒径０．５〜２．０mm、比表面積３５ｍ
2 ／ｇ）１０ｇを投入し、３０分間浸漬した。その後、
溶液からチタニア粒子を分離し、空気中で、８０℃、１
００℃、１２０℃で各２時間乾燥した。続いて、酸素２
０％を含む窒素気流下で１２０℃から５００℃まで５時
間かけで昇温し、５００℃で４時間焼成して、チタニア
に対してＷを９重量％（金属元素換算値）担持したＷ系
浄化材（第二の触媒）を調製した。Next, water (6.2 ml) was added to 1.8 g of ammonium tungstate parapentapentahydrate and 1.0 g of oxalic acid, and dissolved by heating on a water bath, and then titania (particles) was added to the cooled aqueous solution. Diameter 0.5-2.0mm, specific surface area 35m
2 / g) 10 g was added and immersed for 30 minutes. afterwards,
Separate the titania particles from the solution and in air at 80 ° C, 1
It dried at 00 degreeC and 120 degreeC for 2 hours each. Then, oxygen 2
A temperature of 120 ° C. to 500 ° C. in 5 hours under a nitrogen gas stream containing 0%, and calcined at 500 ° C. for 4 hours to carry 9% by weight of W to titania (converted to metal element). A purifying material (second catalyst) was prepared.
【００４７】さらに、ペレット状γ−アルミナ（直径
１．５ｍｍ、長さ約２〜３ｍｍ、比表面積２６０ｍ2 ／
ｇ）に塩化白金酸水溶液を用いて、γ−アルミナに対し
て０．２重量％（金属元素換算値）の白金を担持し、乾
燥後、７００℃まで焼成し、白金系触媒（第三の触媒）
を調製した。Further, pelletized γ-alumina (diameter: 1.5 mm, length: about 2 to 3 mm, specific surface area: 260 m 2 /
g) using an aqueous chloroplatinic acid solution, carrying 0.2% by weight (in terms of metal element) of platinum with respect to γ-alumina, drying and calcining to 700 ° C. to form a platinum-based catalyst (third catalyst). catalyst)
Was prepared.
【００４８】排ガスの流入側から流出側へ順番に銀系触
媒約３．６ｇ、Ｗ系触媒約３．６ｇ、白金系触媒約１．
２ｇを反応管内にセットした。次に、表１に示す組成の
模擬排ガス（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、４５０℃、１０
０時間流した後（銀系触媒の空間速度約３０，０００ｈ
-1、Ｗ系触媒の空間速度約３０，０００ｈ-1、白金系触
媒の空間速度は約９０，０００ｈ-1）、反応管内の排ガ
ス温度を３００℃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。In order from the inflow side to the outflow side of the exhaust gas, about 3.6 g of a silver-based catalyst, about 3.6 g of a W-based catalyst, and about 1.
2 g was set in the reaction tube. Next, simulated exhaust gas (nitrogen monoxide, carbon monoxide, oxygen, ethanol, propylene, sulfur dioxide, nitrogen, and water) having the composition shown in Table 1 was flowed at a flow rate of 4.4 liters per minute (standard state) at 450 ° C. , 10
After flowing for 0 hours (space velocity of the silver-based catalyst is about 30,000 h
-1 , the space velocity of the W-based catalyst is about 30,000 h -1 , the space velocity of the platinum-based catalyst is about 90,000 h -1 ), and the exhaust gas temperature in the reaction tube is changed from 300 ° C. to 600 ° C. every 50 ° C. At each temperature, ethanol and nitrogen oxide were reacted.
【００４９】 表１ 成分 濃度 一酸化窒素 800 ppm （乾燥ベース） 一酸化炭素 100 ppm （乾燥ベース） 酸素 10 容量％ （乾燥ベース） エタノール 1250 ppm （乾燥ベース） （一酸化窒素の重量の３倍） 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 concentrations Nitric oxide 800 ppm (dry basis) Carbon monoxide 100 ppm (dry basis) Oxygen 10% by volume (dry basis) Ethanol 1250 ppm (dry basis) (3 times the weight of nitric oxide) Propylene 100 ppm (dry basis) Sulfur dioxide 80 ppm (dry basis) Nitrogen Residual moisture 10% by volume (based on the total volume of the above components)
【００５０】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。一酸化炭素及び炭
化水素の濃度はそれぞれＣＯ計、ＨＣ計により測定し、
排ガス中にエタノールを添加しない条件で一酸化炭素及
び炭化水素の除去率を求めた。結果を表２に示す。The nitrogen oxides (NO +
The concentration of NO 2 ) was measured with a chemiluminescent nitrogen oxide analyzer to determine the nitrogen oxide removal rate. The concentrations of carbon monoxide and hydrocarbons were measured with a CO meter and a HC meter, respectively.
The removal rates of carbon monoxide and hydrocarbons were determined under the condition that ethanol was not added to the exhaust gas. Table 2 shows the results.
【００５１】実施例２ 実施例１と同様の粉末状シリカ・アルミナ（比表面積３
５０ｍ2 ／ｇ）に硝酸銀水溶液と塩化アンモニウムを用
いて沈澱法で塩化銀を４重量％（銀元素換算値）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１２．５ｍｍ、４０
０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 The same powdery silica-alumina as in Example 1 (specific surface area: 3
About 1.0 g of a catalyst in which 4 wt% of silver chloride (in terms of silver element) was supported by a precipitation method using an aqueous solution of silver nitrate and ammonium chloride in 50 m 2 / g), and a commercially available cordierite honeycomb molded body (diameter: 30mm, length about 12.5mm, 40
0 cells / inch 2 ), dried and baked stepwise to 600 ° C. to prepare a silver-based purifying material (a purifying material coated with a first catalyst).
【００５２】次に、水３０mlにＶ2 Ｏ 5を２０ｇ懸濁さ
せて、水浴上で約９０℃に保ちながら１時間攪拌した。
放冷した後、水を加えて８０mlにした。この水溶液を４
ml採取し、水を２．８ml加えて６．８mlとした後、粉末
チタニア（比表面積５０ｍ2／ｇ）１０ｇを投入し、３
０分間浸漬し、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にスラリーを１．０ｇ（乾燥ベー
ス）コートした。チタニアに対してＶ2 Ｏ 5の含有量は
５重量％（金属元素換算値）であった。実施例１のＷＯ
3 ／チタニア触媒と同様の条件で乾燥、焼成を行い、Ｖ
系浄化材（第二の触媒をコートした浄化材）を調製し
た。Next, 20 g of V 2 O 5 was suspended in 30 ml of water, and the mixture was stirred on a water bath at about 90 ° C. for 1 hour.
After allowing to cool, water was added to make up to 80 ml. This aqueous solution
After sampling 2.8 ml of water and adding 2.8 ml of water to make 6.8 ml, 10 g of powdered titania (specific surface area: 50 m 2 / g) was added, and
It was immersed for 0 minutes to form a slurry. 1.0 g (dry base) of a slurry was coated on a honeycomb-shaped formed body similar to the silver-based purifying material. The content of V 2 O 5 relative to titania was 5% by weight (in terms of metal element). WO of Example 1
3 / Dried and calcined under the same conditions as for the titania catalyst.
A system purification material (a purification material coated with a second catalyst) was prepared.
【００５３】また、粉末状γ−アルミナ（比表面積２０
０ｍ2 ／ｇ）に塩化白金酸溶液を用いてPtが０．２重量
％担持したあとスラリー状にし、同様のハニカム状成形
体（長さ４．２mm）に０．４ｇ（乾燥重量）コートし、
乾燥後、７００℃まで焼成し、白金系浄化材（第三の触
媒をコートした浄化材）を調製した。Further, powdery γ-alumina (specific surface area 20
0 m 2 / g), 0.2% by weight of Pt was supported using a chloroplatinic acid solution, and then slurried. A similar honeycomb-shaped formed body (4.2 mm in length) was coated with 0.4 g (dry weight). ,
After drying, it was fired to 700 ° C. to prepare a platinum-based purifying material (a purifying material coated with a third catalyst).
【００５４】排ガスの流入側から流出側へ順番に銀系浄
化材、Ｖ系浄化材、白金系浄化材を反応管内にセット
し、表１に示す組成のガスで実施例１と同様に評価した
（銀系浄化材の空間速度約３０，０００ｈ-1、Ｖ系浄化
材の空間速度約３０，０００ｈ-1、白金系浄化材の空間
速度は約９０，０００ｈ-1）。実験結果を表２に示す。A silver-based purifying material, a V-based purifying material, and a platinum-based purifying material were set in a reaction tube in order from the inflow side to the outflow side of the exhaust gas, and evaluated in the same manner as in Example 1 using gases having the compositions shown in Table 1. (The space velocity of the silver-based purifying material is about 30,000 h -1 , the space velocity of the V-based purifying material is about 30,000 h -1 , and the space velocity of the platinum-based purifying material is about 90,000 h -1 ). Table 2 shows the experimental results.
【００５５】実施例３ 実施例２と同様に粉末チタニア（比表面積５０ｍ2 ／
ｇ）にＷ、Ｖの酸化物をそれぞれ４重量％、２重量％
（金属元素換算値）担持した触媒１．０ｇ（乾燥ベー
ス）をスラリー状にした。実施例２と同様のハニカム状
成形体（直径３０mm、長さ１２．５mm、４００セル／平
方インチ）にこのスラリーをコートした。実施例２と同
様の条件で乾燥、焼成を行い、Ｗ、Ｖ系浄化材を調製し
た。 Example 3 In the same manner as in Example 2, powdered titania (specific surface area: 50 m 2 /
g) containing 4% by weight and 2% by weight of oxides of W and V, respectively.
(Value in terms of metal element) 1.0 g (dry base) of the supported catalyst was made into a slurry. This slurry was coated on a honeycomb formed body (diameter 30 mm, length 12.5 mm, 400 cells / square inch) similar to that in Example 2. Drying and firing were performed under the same conditions as in Example 2 to prepare W and V-based purifying materials.
【００５６】排ガスの流入側から流出側へ順番に実施例
２の銀系浄化材、上記Ｗ、Ｖ系浄化材及び実施例２の白
金系浄化材を反応管内にセットし、表１に示す組成のガ
スで実施例２と同じ条件で評価した（銀系浄化材の空間
速度約３０，０００ｈ-1、Ｗ、Ｖ系浄化材の空間速度は
約３０，０００ｈ-1、白金系浄化材の空間速度は約９
０，０００ｈ-1）。実験結果を表２に示す。The silver-based purifying material of Example 2, the W and V-based purifying materials and the platinum-based purifying material of Example 2 were set in the reaction tube in order from the inflow side to the outflow side of the exhaust gas. was evaluated under the same conditions as in example 2 with the gas (space velocity of about 30,000 h -1 of silver-based purification material, W, space velocity of about 30,000 h -1 of the V-based purification material, spatial platinum-based purification material Speed is about 9
000h- 1 ). Table 2 shows the experimental results.
【００５７】比較例１ 実施例１と同様な方法で市販のペレット状γ−アルミナ
（直径１．５ｍｍ、長さ約２〜３ｍｍ、比表面積２６０
ｍ2 ／ｇ）に銀を４重量％担持して銀系浄化材を作成し
た。３．６ｇの銀系浄化材を反応管にセットし、表１に
示す組成のガスを用いて実施例１と同じ条件で（空間速
度は約３０，０００ｈ-1）評価した。実験結果を表２に
示す。 Comparative Example 1 A commercially available pelletized γ-alumina (1.5 mm in diameter, about 2-3 mm in length, specific surface area of 260) was prepared in the same manner as in Example 1.
m 2 / g) to support 4% by weight of silver to prepare a silver-based purifying material. 3.6 g of a silver-based purifying material was set in a reaction tube, and evaluated using a gas having a composition shown in Table 1 under the same conditions as in Example 1 (space velocity: about 30,000 h -1 ). Table 2 shows the experimental results.
【００５８】比較例２ 比較例１と同様な方法で作成した銀系浄化材を７．２ｇ
反応管にセットし、表１に示す組成のガスを用いて実施
例１と同じ条件で（空間速度は約１５，０００ｈ-1）評
価した。実験結果を表２に示す。 Comparative Example 2 7.2 g of a silver-based purifying material prepared in the same manner as in Comparative Example 1
The sample was set in a reaction tube, and evaluated using the gas having the composition shown in Table 1 under the same conditions as in Example 1 (space velocity: about 15,000 h -1 ). Table 2 shows the experimental results.
【００５９】 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 実施例３ 比較例１ 比較例２ ３００ ＮＯｘ ７０ ７２ ６８ ２６ ５０ ＣＯ ８２ ８４ ８０ ３１ ４５ ＨＣ ６１ ６３ ６０ ２５ ３０ ３５０ ＮＯｘ ７９ ８３ ７８ ４２ ６５ ＣＯ ８６ ８８ ８２ ５２ ６１ ＨＣ ６５ ６７ ６３ ２７ ３８ ４００ ＮＯｘ ９０ ９５ ９４ ５２ ８０ ＣＯ ９１ ９５ ９３ ５８ ６５ ＨＣ ７８ ８０ ８２ ３４ ４１ ４５０ ＮＯｘ ９４ ９８ ９７ ６０ ８４ ＣＯ ９８ １００ ９８ ６８ ７５ ＨＣ ８２ ８４ ８５ ５８ ６１ ５００ ＮＯｘ ７６ ７３ ７５ ５０ ７５ ＣＯ １００ １００ １００ ７６ ８２ ＨＣ ９６ ９８ ９８ ６５ ７２ ５５０ ＮＯｘ ５０ ４８ ５２ ３８ ４７ ＣＯ １００ １００ １００ ８２ ９２ ＨＣ １００ １００ １００ ７１ ８２ ６００ ＮＯｘ ４０ ３８ ４０ ２６ ３８ ＣＯ １００ １００ １００ ８８ ９６ ＨＣ １００ １００ １００ ７８ ８４ Table 2 Removal rates of nitrogen oxides (NOx), carbon monoxide (CO), and hydrocarbons (HC) Reaction temperature Removal components Removal rate (%) (° C.) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 300 NOx 70 72 68 26 50 CO 82 84 80 3 145 HC 61 63 60 25 30 350 NOx 79 83 78 78 42 65 CO 86 88 82 52 61 HC 65 67 63 27 38 38 400 NOx 90 95 9552 91 95 93 58 65 HC 78 80 82 34 34 450 450 NOx 94 98 97 60 84 CO 98 100 98 68 75 HC 82 84 85 85 58 61 500 NOx 76 73 75 50 75 75 CO 100 100 100 76 82 50 96 96 98 98 98 NOx 50 48 52 38 47 CO 100 100 100 82 82 HC 100 100 100 71 71 82 600 NOx 40 38 40 26 38 CO 100 100 100 100 88 96 HC 100 100 100 78 84
【００６０】表２に示すように、比較例１及び２に比べ
て、実施例１〜３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、第一の触媒の多孔質
無機酸化物にシリカ・アルミナ複合酸化物を用いること
により、二酸化硫黄による除去率の低下は小さかった。As shown in Table 2, as compared with Comparative Examples 1 and 2, Examples 1 to 3 show more effective removal of nitrogen oxides over a wide temperature range, and have higher carbon monoxide and hydrocarbons even in a low temperature range. Was obtained. Further, by using the silica / alumina composite oxide as the porous inorganic oxide of the first catalyst, the reduction in the removal rate by sulfur dioxide was small.
【００６１】[0061]
【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, the use of the exhaust gas purifying material of the present invention makes it possible to efficiently remove nitrogen oxides in exhaust gas containing excess oxygen in a wide temperature range. INDUSTRIAL APPLICABILITY The exhaust gas purifying material and the purification method of the present invention can be widely used for purifying exhaust gas of various types of 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 23/28 ＺＡＢ Ａ 23/30 ＺＡＢ Ａ 23/42 ＺＡＢ Ａ 23/44 ＺＡＢ Ａ 23/46 ＺＡＢ Ａ ３０１ Ａ ３１１ Ａ 23/50 ＺＡＢ Ａ 23/52 ＺＡＢ Ａ 27/10 ＺＡＢ Ａ Ｂ０１Ｄ 53/36 １０４ Ａ ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 6 Identification number Agency reference number FI Technical indication B01J 23/28 ZAB A 23/30 ZAB A 23/42 ZAB A 23/44 ZAB A 23/46 ZAB A 301 A 311 A 23/50 ZAB A 23/52 ZAB A 27/10 ZAB A B01D 53/36 104 A
Claims (8)
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、多孔質の無機酸化物に前記無機酸化物の０．２〜
１５重量％（銀元素換算値）の銀及び／又は銀化合物、
又はそれらの混合物を担持してなる第一の触媒と、多孔
質の無機酸化物に前記無機酸化物の０．５〜３０重量％
（金属元素換算値）のＷ、Ｖ、Ｍｏ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を担持してなる第二
の触媒と、多孔質の無機酸化物に前記無機酸化物の５重
量％以下（金属元素換算値）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
持してなる第三の触媒とからなることを特徴とする排ガ
ス浄化材。1. A method for reducing and removing nitrogen oxides from a flue gas containing nitrogen oxides and oxygen in excess of a theoretical reaction amount for coexisting unburned components, and also oxidizing residual and unreacted carbon monoxide and hydrocarbons. In the exhaust gas purifying material to be removed, the porous inorganic oxide is added to the inorganic oxide in an amount of 0.2 to 0.2%.
15% by weight (in terms of silver element) of silver and / or a silver compound,
Or a first catalyst carrying a mixture thereof, and 0.5 to 30% by weight of the inorganic oxide in the porous inorganic oxide.
A second catalyst supporting an oxide of at least one element selected from the group consisting of W, V, and Mo (in terms of metal elements); Pt, Pd, Ru, Rh, Ir and
An exhaust gas purifying material comprising: a third catalyst supporting at least one element selected from the group consisting of Au.
て、前記浄化材は排ガス流入側から流出側へ順に前記第
一の触媒、前記第二の触媒、前記第三の触媒を有するこ
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 includes the first catalyst, the second catalyst, and the third catalyst in order from an exhaust gas inflow side to an outflow side. Exhaust gas 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の酸化物を５０重量％
以下含有するアルミナ複合酸化物で、第二の触媒ではチ
タニア単独、又はアルミナ、ジルコニア、シリカからな
る群より選ばれた少なくとも一種の酸化物を含有するチ
タニア複合酸化物で、第三の触媒ではアルミナ、チタニ
ア、ジルコニア、シリカからなる群より選ばれた少なく
とも一種の酸化物であることを特徴とする排ガス浄化
材。3. The exhaust gas purifying material according to claim 1, wherein the porous inorganic oxide is at least one selected from the group consisting of alumina alone or silica, titania and zirconia in the first catalyst. 50% by weight of oxide
The following contains alumina composite oxide, the second catalyst is titania alone, or alumina, zirconia, a titania composite oxide containing at least one oxide selected from the group consisting of silica, the third catalyst is alumina An exhaust gas purifying material, which is at least one oxide selected from the group consisting of, titania, zirconia, and silica.
浄化材において、前記浄化材は前記第一、第二及び第三
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 formed by coating the first, second, and third catalysts on the surface of a ceramic or metal substrate. An exhaust gas purifying material comprising:
浄化材において、前記第一、第二及び第三の触媒の多孔
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, second and third catalysts are each in the form of pellets or granules. Exhaust gas purifying material.
浄化材において、前記銀化合物は銀の酸化物、塩化銀、
硫酸銀及び燐酸銀からなる群より選ばれた少なくとも一
種であることを特徴とする排ガス浄化材。6. The exhaust gas purifying material according to claim 1, wherein the silver compound is an oxide of silver, silver chloride,
An exhaust gas purifying material, which is at least one selected from the group consisting of silver sulfate and silver phosphate.
浄化材において、前記第一の触媒の多孔質無機酸化物は
アルミナとシリカからなるアルミナ複合酸化物であるこ
とを特徴とする排ガス浄化材。7. The exhaust gas purifying material according to claim 1, wherein the porous inorganic oxide of the first catalyst is an alumina composite oxide comprising alumina and silica. 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１〜７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、１５０〜６００℃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。8. A method for reducing and removing nitrogen oxides from a flue gas containing nitrogen oxides and oxygen in excess of a theoretical reaction amount for coexisting unburned components, and also oxidizing residual and unreacted carbon monoxide and hydrocarbons. In the exhaust gas purifying method for removing, using the exhaust gas purifying material according to any one of claims 1 to 7, the exhaust gas purifying material is installed in the middle of an exhaust gas conduit, and hydrocarbons and / or carbon are disposed upstream of the purifying material. Number 2
The oxygen-containing organic compound or the exhaust gas to which the fuel containing it is added is brought into contact with the purifying material at 150 to 600 ° C., thereby removing the nitrogen oxides by the reaction with the oxygen-containing organic compound in the exhaust gas. A method for purifying exhaust gas, comprising oxidizing and removing residual and unreacted carbon monoxide and hydrocarbons.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6218176A JPH0857263A (en) | 1994-08-19 | 1994-08-19 | Exhaust gas purifying material and method therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6218176A JPH0857263A (en) | 1994-08-19 | 1994-08-19 | Exhaust gas purifying material and method therefor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0857263A true JPH0857263A (en) | 1996-03-05 |
Family
ID=16715811
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6218176A Pending JPH0857263A (en) | 1994-08-19 | 1994-08-19 | Exhaust gas purifying material and method therefor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0857263A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100382051B1 (en) * | 2000-12-29 | 2003-05-09 | 한국전력기술 주식회사 | Catalyst for Selective Catalytic Reduction of Nitrogen Oxides Including Sulfur Dioxide at Low Temperature |
| JP2010504206A (en) * | 2006-09-20 | 2010-02-12 | ビーエーエスエフ、カタリスツ、エルエルシー | Catalyst and production method for reducing NOx in exhaust gas stream |
-
1994
- 1994-08-19 JP JP6218176A patent/JPH0857263A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100382051B1 (en) * | 2000-12-29 | 2003-05-09 | 한국전력기술 주식회사 | Catalyst for Selective Catalytic Reduction of Nitrogen Oxides Including Sulfur Dioxide at Low Temperature |
| JP2010504206A (en) * | 2006-09-20 | 2010-02-12 | ビーエーエスエフ、カタリスツ、エルエルシー | Catalyst and production method for reducing NOx in exhaust gas stream |
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