JP4895858B2 - New exhaust gas purification method - Google Patents
New exhaust gas purification method Download PDFInfo
- Publication number
- JP4895858B2 JP4895858B2 JP2007042564A JP2007042564A JP4895858B2 JP 4895858 B2 JP4895858 B2 JP 4895858B2 JP 2007042564 A JP2007042564 A JP 2007042564A JP 2007042564 A JP2007042564 A JP 2007042564A JP 4895858 B2 JP4895858 B2 JP 4895858B2
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- nox
- exhaust gas
- mesoporous
- nitride
- 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.)
- Expired - Fee Related
Links
- 238000000034 method Methods 0.000 title claims description 46
- 238000000746 purification Methods 0.000 title claims description 38
- 239000003054 catalyst Substances 0.000 claims description 155
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 48
- -1 carbon nitride compound Chemical class 0.000 claims description 24
- 239000003463 adsorbent Substances 0.000 claims description 22
- 150000001875 compounds Chemical class 0.000 claims description 19
- 239000013335 mesoporous material Substances 0.000 claims description 19
- 229910052697 platinum Inorganic materials 0.000 claims description 19
- 238000001179 sorption measurement Methods 0.000 claims description 16
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 10
- 229910052796 boron Inorganic materials 0.000 claims description 10
- 238000002485 combustion reaction Methods 0.000 claims description 10
- 230000033116 oxidation-reduction process Effects 0.000 claims description 5
- 239000010936 titanium Substances 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- 239000007789 gas Substances 0.000 description 77
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 49
- 239000011148 porous material Substances 0.000 description 42
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 38
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 38
- 238000004519 manufacturing process Methods 0.000 description 36
- 239000003638 chemical reducing agent Substances 0.000 description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 21
- 229910052757 nitrogen Inorganic materials 0.000 description 20
- 239000000377 silicon dioxide Substances 0.000 description 20
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 17
- 239000001301 oxygen Substances 0.000 description 17
- 229910052760 oxygen Inorganic materials 0.000 description 17
- 239000002245 particle Substances 0.000 description 17
- 239000012298 atmosphere Substances 0.000 description 16
- 239000010457 zeolite Substances 0.000 description 16
- 229910021536 Zeolite Inorganic materials 0.000 description 15
- 238000006243 chemical reaction Methods 0.000 description 15
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 15
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 14
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 14
- 239000000446 fuel Substances 0.000 description 13
- 239000000463 material Substances 0.000 description 12
- 238000002407 reforming Methods 0.000 description 12
- 229910018967 Pt—Rh Inorganic materials 0.000 description 11
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 10
- 238000009826 distribution Methods 0.000 description 10
- 230000009467 reduction Effects 0.000 description 10
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 9
- 230000000694 effects Effects 0.000 description 9
- 229930195733 hydrocarbon Natural products 0.000 description 9
- 150000002430 hydrocarbons Chemical class 0.000 description 9
- 239000000126 substance Substances 0.000 description 9
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 8
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 8
- 230000003197 catalytic effect Effects 0.000 description 8
- 239000001307 helium Substances 0.000 description 8
- 229910052734 helium Inorganic materials 0.000 description 8
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 8
- 239000012153 distilled water Substances 0.000 description 7
- 238000005259 measurement Methods 0.000 description 7
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 6
- 229910002091 carbon monoxide Inorganic materials 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 239000010453 quartz Substances 0.000 description 6
- 239000004094 surface-active agent Substances 0.000 description 6
- 229910052723 transition metal Inorganic materials 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000002243 precursor Substances 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- 238000005406 washing Methods 0.000 description 5
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 4
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 4
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 4
- YRKCREAYFQTBPV-UHFFFAOYSA-N acetylacetone Chemical compound CC(=O)CC(C)=O YRKCREAYFQTBPV-UHFFFAOYSA-N 0.000 description 4
- JRBPAEWTRLWTQC-UHFFFAOYSA-N dodecylamine Chemical compound CCCCCCCCCCCCN JRBPAEWTRLWTQC-UHFFFAOYSA-N 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 150000002431 hydrogen Chemical class 0.000 description 4
- 239000000395 magnesium oxide Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 150000002736 metal compounds Chemical class 0.000 description 4
- 150000004767 nitrides Chemical class 0.000 description 4
- JMANVNJQNLATNU-UHFFFAOYSA-N oxalonitrile Chemical class N#CC#N JMANVNJQNLATNU-UHFFFAOYSA-N 0.000 description 4
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 4
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 239000010948 rhodium Substances 0.000 description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 3
- 229910052582 BN Inorganic materials 0.000 description 3
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 3
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- 229910002651 NO3 Inorganic materials 0.000 description 3
- 239000002202 Polyethylene glycol Substances 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 150000001298 alcohols Chemical class 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 239000000292 calcium oxide Substances 0.000 description 3
- 235000012255 calcium oxide Nutrition 0.000 description 3
- 238000006555 catalytic reaction Methods 0.000 description 3
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 3
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 229910017052 cobalt Inorganic materials 0.000 description 3
- 239000010941 cobalt Substances 0.000 description 3
- 239000008119 colloidal silica Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 238000005342 ion exchange Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 229920001223 polyethylene glycol Polymers 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 239000003381 stabilizer Substances 0.000 description 3
- 239000011232 storage material Substances 0.000 description 3
- 229910052721 tungsten Inorganic materials 0.000 description 3
- 239000010937 tungsten Substances 0.000 description 3
- WTHDKMILWLGDKL-UHFFFAOYSA-N urea;hydrate Chemical compound O.NC(N)=O WTHDKMILWLGDKL-UHFFFAOYSA-N 0.000 description 3
- JYEUMXHLPRZUAT-UHFFFAOYSA-N 1,2,3-triazine Chemical group C1=CN=NN=C1 JYEUMXHLPRZUAT-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 2
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- GQPLMRYTRLFLPF-UHFFFAOYSA-N Nitrous Oxide Chemical compound [O-][N+]#N GQPLMRYTRLFLPF-UHFFFAOYSA-N 0.000 description 2
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 2
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- PPWPWBNSKBDSPK-UHFFFAOYSA-N [B].[C] Chemical compound [B].[C] PPWPWBNSKBDSPK-UHFFFAOYSA-N 0.000 description 2
- 229910000272 alkali metal oxide Inorganic materials 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- 229910000287 alkaline earth metal oxide Inorganic materials 0.000 description 2
- 150000004703 alkoxides Chemical class 0.000 description 2
- 229910001422 barium ion Inorganic materials 0.000 description 2
- IWOUKMZUPDVPGQ-UHFFFAOYSA-N barium nitrate Chemical compound [Ba+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O IWOUKMZUPDVPGQ-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 150000001768 cations Chemical class 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 229910052878 cordierite Inorganic materials 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000003795 desorption Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000000921 elemental analysis Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 150000004679 hydroxides Chemical class 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 229910052741 iridium Inorganic materials 0.000 description 2
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 239000002808 molecular sieve Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 125000004433 nitrogen atom Chemical group N* 0.000 description 2
- 229910000510 noble metal Inorganic materials 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229910052763 palladium Inorganic materials 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- PXXKQOPKNFECSZ-UHFFFAOYSA-N platinum rhodium Chemical compound [Rh].[Pt] PXXKQOPKNFECSZ-UHFFFAOYSA-N 0.000 description 2
- 229920002239 polyacrylonitrile Polymers 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- KIDHWZJUCRJVML-UHFFFAOYSA-N putrescine Chemical compound NCCCCN KIDHWZJUCRJVML-UHFFFAOYSA-N 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 238000001988 small-angle X-ray diffraction Methods 0.000 description 2
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000002336 sorption--desorption measurement Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 229910000314 transition metal oxide Inorganic materials 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- 238000001291 vacuum drying Methods 0.000 description 2
- 238000003828 vacuum filtration Methods 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- LNAZSHAWQACDHT-XIYTZBAFSA-N (2r,3r,4s,5r,6s)-4,5-dimethoxy-2-(methoxymethyl)-3-[(2s,3r,4s,5r,6r)-3,4,5-trimethoxy-6-(methoxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6r)-4,5,6-trimethoxy-2-(methoxymethyl)oxan-3-yl]oxyoxane Chemical compound CO[C@@H]1[C@@H](OC)[C@H](OC)[C@@H](COC)O[C@H]1O[C@H]1[C@H](OC)[C@@H](OC)[C@H](O[C@H]2[C@@H]([C@@H](OC)[C@H](OC)O[C@@H]2COC)OC)O[C@@H]1COC LNAZSHAWQACDHT-XIYTZBAFSA-N 0.000 description 1
- KLFRPGNCEJNEKU-FDGPNNRMSA-L (z)-4-oxopent-2-en-2-olate;platinum(2+) Chemical compound [Pt+2].C\C([O-])=C\C(C)=O.C\C([O-])=C\C(C)=O KLFRPGNCEJNEKU-FDGPNNRMSA-L 0.000 description 1
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 1
- BSKHPKMHTQYZBB-UHFFFAOYSA-N 2-methylpyridine Chemical compound CC1=CC=CC=N1 BSKHPKMHTQYZBB-UHFFFAOYSA-N 0.000 description 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229910052580 B4C Inorganic materials 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical class OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 229920000877 Melamine resin Polymers 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 1
- 206010058667 Oral toxicity Diseases 0.000 description 1
- 101150003085 Pdcl gene Proteins 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000000862 absorption spectrum Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 150000003973 alkyl amines Chemical class 0.000 description 1
- 150000005215 alkyl ethers Chemical class 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000003125 aqueous solvent Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- RRZKHZBOZDIQJG-UHFFFAOYSA-N azane;manganese Chemical compound N.[Mn] RRZKHZBOZDIQJG-UHFFFAOYSA-N 0.000 description 1
- BCZWPKDRLPGFFZ-UHFFFAOYSA-N azanylidynecerium Chemical compound [Ce]#N BCZWPKDRLPGFFZ-UHFFFAOYSA-N 0.000 description 1
- GPBUGPUPKAGMDK-UHFFFAOYSA-N azanylidynemolybdenum Chemical compound [Mo]#N GPBUGPUPKAGMDK-UHFFFAOYSA-N 0.000 description 1
- CFJRGWXELQQLSA-UHFFFAOYSA-N azanylidyneniobium Chemical compound [Nb]#N CFJRGWXELQQLSA-UHFFFAOYSA-N 0.000 description 1
- CUOITRGULIVMPC-UHFFFAOYSA-N azanylidynescandium Chemical compound [Sc]#N CUOITRGULIVMPC-UHFFFAOYSA-N 0.000 description 1
- SKKMWRVAJNPLFY-UHFFFAOYSA-N azanylidynevanadium Chemical compound [V]#N SKKMWRVAJNPLFY-UHFFFAOYSA-N 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- INAHAJYZKVIDIZ-UHFFFAOYSA-N boron carbide Chemical compound B12B3B4C32B41 INAHAJYZKVIDIZ-UHFFFAOYSA-N 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 238000005341 cation exchange Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000009841 combustion method Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 150000002009 diols Chemical class 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 description 1
- 230000008570 general process Effects 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- 229920001519 homopolymer Polymers 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 238000004949 mass spectrometry Methods 0.000 description 1
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 235000010981 methylcellulose Nutrition 0.000 description 1
- 239000000693 micelle Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052680 mordenite Inorganic materials 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 238000005121 nitriding Methods 0.000 description 1
- 229940005654 nitrite ion Drugs 0.000 description 1
- 229960001730 nitrous oxide Drugs 0.000 description 1
- 235000013842 nitrous oxide Nutrition 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 231100000418 oral toxicity Toxicity 0.000 description 1
- 229910052762 osmium Inorganic materials 0.000 description 1
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 231100000572 poisoning Toxicity 0.000 description 1
- 230000000607 poisoning effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 150000003242 quaternary ammonium salts Chemical class 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000006057 reforming reaction Methods 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 229910052702 rhenium Inorganic materials 0.000 description 1
- WUAPFZMCVAUBPE-UHFFFAOYSA-N rhenium atom Chemical compound [Re] WUAPFZMCVAUBPE-UHFFFAOYSA-N 0.000 description 1
- VXNYVYJABGOSBX-UHFFFAOYSA-N rhodium(3+);trinitrate Chemical compound [Rh+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VXNYVYJABGOSBX-UHFFFAOYSA-N 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 238000003980 solgel method Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000000629 steam reforming Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 150000003871 sulfonates Chemical class 0.000 description 1
- 238000006557 surface reaction Methods 0.000 description 1
- 238000010301 surface-oxidation reaction Methods 0.000 description 1
- MZLGASXMSKOWSE-UHFFFAOYSA-N tantalum nitride Chemical compound [Ta]#N MZLGASXMSKOWSE-UHFFFAOYSA-N 0.000 description 1
- OQTSOKXAWXRIAC-UHFFFAOYSA-N tetrabutan-2-yl silicate Chemical compound CCC(C)O[Si](OC(C)CC)(OC(C)CC)OC(C)CC OQTSOKXAWXRIAC-UHFFFAOYSA-N 0.000 description 1
- UQMOLLPKNHFRAC-UHFFFAOYSA-N tetrabutyl silicate Chemical compound CCCCO[Si](OCCCC)(OCCCC)OCCCC UQMOLLPKNHFRAC-UHFFFAOYSA-N 0.000 description 1
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 1
- ZQZCOBSUOFHDEE-UHFFFAOYSA-N tetrapropyl silicate Chemical compound CCCO[Si](OCCC)(OCCC)OCCC ZQZCOBSUOFHDEE-UHFFFAOYSA-N 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 150000003623 transition metal compounds Chemical class 0.000 description 1
- DKZXTOPFCDDGGX-UHFFFAOYSA-N tri-s-triazine Chemical group C1=NC(N23)=NC=NC2=NC=NC3=N1 DKZXTOPFCDDGGX-UHFFFAOYSA-N 0.000 description 1
- FAQYAMRNWDIXMY-UHFFFAOYSA-N trichloroborane Chemical compound ClB(Cl)Cl FAQYAMRNWDIXMY-UHFFFAOYSA-N 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- JLQFVGYYVXALAG-CFEVTAHFSA-N yasmin 28 Chemical compound OC1=CC=C2[C@H]3CC[C@](C)([C@](CC4)(O)C#C)[C@@H]4[C@@H]3CCC2=C1.C([C@]12[C@H]3C[C@H]3[C@H]3[C@H]4[C@@H]([C@]5(CCC(=O)C=C5[C@@H]5C[C@@H]54)C)CC[C@@]31C)CC(=O)O2 JLQFVGYYVXALAG-CFEVTAHFSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
- ZVWKZXLXHLZXLS-UHFFFAOYSA-N zirconium nitride Chemical compound [Zr]#N ZVWKZXLXHLZXLS-UHFFFAOYSA-N 0.000 description 1
Description
本発明は、内燃機関の排ガスに含まれるＮＯｘを浄化するための新規触媒を用いた排ガス浄化方法に関する。 The present invention relates to an exhaust gas purification method using a novel catalyst for purifying NOx contained in exhaust gas of an internal combustion engine.
従来、ガソリン車の排ガスに含まれるＮＯｘ、一酸化炭素、及び炭化水素は、白金族元素から成る三元触媒によって浄化されている（特許文献１参照）。三元触媒は、通常、触媒支持体としてコージェライト製のモノリス成形体を用い、該成形体のガス流路内壁に数μｍ〜数十μｍの大きさの活性アルミナ粒子を塗布し、該塗布層に数１０ｎｍ〜数１００ｎｍの大きさの白金−パラジウム−ロジウム粒子を担持させた構造となっている。三元触媒による浄化方法は、空気：燃料の重量混合比である空燃比を理論空燃比（＝１４．７）近傍に制御することで（この燃焼はリッチバーンと呼ばれている）排ガスに含まれる酸素濃度を１％以下に維持できるので、排ガスに含まれる一酸化炭素及び炭化水素をＮＯｘの還元剤として利用できるという利点を持つが、排ガス中の酸素濃度が数％以上になると触媒の著しい酸化劣化が生じるという問題がある。 Conventionally, NOx, carbon monoxide, and hydrocarbons contained in exhaust gas from gasoline vehicles have been purified by a three-way catalyst composed of a platinum group element (see Patent Document 1). The three-way catalyst usually uses a cordierite monolith molded body as the catalyst support, and the activated alumina particles having a size of several μm to several tens of μm are applied to the inner wall of the gas flow path of the molded body. In this structure, platinum-palladium-rhodium particles having a size of several tens of nanometers to several hundreds of nanometers are supported. The purification method with a three-way catalyst is included in the exhaust gas by controlling the air-fuel ratio, which is the air: fuel weight mixing ratio, close to the theoretical air-fuel ratio (= 14.7) (this combustion is called rich burn). Since the oxygen concentration can be maintained at 1% or less, carbon monoxide and hydrocarbons contained in the exhaust gas can be used as a reducing agent for NOx. However, when the oxygen concentration in the exhaust gas exceeds several percent, the catalyst There is a problem that oxidation deterioration occurs.
また、軽油燃料で走行するトラック、バス等の大型ディーゼル車の排ガス処理は、触媒として遷移金属化合物又は白金族元素を用い還元剤として尿素水を用いる、所謂尿素ＳＣＲ法が検討されている（特許文献２参照）。この方法は、１００℃付近の比較的低温領域から６００℃付近の比較的高温領域に渡ってＮＯｘを効率的に浄化できるという利点を持つが、還元剤として高価な尿素水の搭載が必要であるという問題と、２００℃付近以下の低温排ＮＯｘの多くが硝酸アンモニウムとして排出されるので水質環境汚染を招くという問題がある。 In addition, a so-called urea SCR method using a transition metal compound or a platinum group element as a catalyst and urea water as a reducing agent has been studied for exhaust gas treatment of large diesel vehicles such as trucks and buses that run on light oil fuel (patents). Reference 2). This method has the advantage of being able to efficiently purify NOx from a relatively low temperature region near 100 ° C. to a relatively high temperature region near 600 ° C., but it requires the mounting of expensive urea water as a reducing agent. There is a problem that most of the low temperature exhaust NOx below about 200 ° C. is discharged as ammonium nitrate, which causes water environmental pollution.
尿素水以外の還元剤を用いる方法としては、自動車燃料（燃料に少量含有されるエチレン、プロピレン等の炭化水素が還元性を有する）を還元剤として用いるハイドロカーボンＳＣＲ法が検討されており、この方法はリッチバーン排ＮＯｘに対しては高い浄化率が得られるが、リーンバーン排ＮＯｘに対しては多量の還元剤が必要なので燃費上の問題がある。また、メタノールを還元剤として用いる方法が提案されているが（非特許文献１参照）、反応開始温度が３００℃以上であるという問題がある。さらに、最近では、燃料を改質触媒で改質後に、排ガスに導入して排ガス浄化用触媒によって排ＮＯｘを処理する方法が提案されているが（特許文献４及び非特許文献２参照、）、反応開始温度が３００℃以上であるという問題がある。また、ディーゼル排ガス等の排ＮＯｘ浄化用に研究されているゼオライト担持触媒は、水熱条件下での水分及び酸素によって著しく活性が低下するという問題がある。 As a method using a reducing agent other than urea water, a hydrocarbon SCR method using an automobile fuel (hydrocarbons such as ethylene and propylene contained in a small amount in the fuel) as a reducing agent has been studied. Although the method can obtain a high purification rate for rich burn exhaust NOx, there is a problem in fuel consumption because a large amount of reducing agent is required for lean burn exhaust NOx. Moreover, although the method of using methanol as a reducing agent is proposed (refer nonpatent literature 1), there exists a problem that reaction start temperature is 300 degreeC or more. Furthermore, recently, after reforming fuel with a reforming catalyst, a method for introducing exhaust gas into exhaust gas and treating exhaust NOx with an exhaust gas purifying catalyst has been proposed (see Patent Document 4 and Non-Patent Document 2). There exists a problem that reaction start temperature is 300 degreeC or more. Further, the zeolite-supported catalyst that has been studied for purifying exhaust NOx such as diesel exhaust gas has a problem that the activity is remarkably lowered by moisture and oxygen under hydrothermal conditions.
一方、ディーゼル乗用車等の小型ディーゼル車の排ＮＯｘ処理には三元触媒が使用できない。それは、空燃比がガソリンの空燃比の数倍以上であるので（ディーゼル燃料の燃焼はリーンバーンである）ディーゼル排ガス中の酸素濃度が通常５％以上であり還元性物質がほとんど含まれていないためである。同様の理由でリーンバーンガソリン車の排ガスも三元触媒では浄化が難しい。リーンバーンガソリン車及び小型ディーゼル車の排ＮＯｘ処理には、現在、触媒として白金族触媒にＮＯｘ吸蔵剤を添加した所謂ＮＯｘ吸蔵還元触媒が検討されている（特許文献３参照）。この方法は、内燃機関がリーンバーンとリッチバーンを交互に繰り返す燃焼方式を行い、リーンバーン排ＮＯｘをＮＯｘ吸蔵剤で吸収し、吸収ＮＯｘをリッチバーン雰囲気下で放出させ、放出ＮＯｘをリッチバーン排ガス中に供給した燃料もしくはリッチバーン排ガス中に存在する多量の一酸化炭素、水素、炭化水素等の還元性物質を用い白金族触媒で還元処理するという考えに立脚している。リーンバー
ンとリッチバーンを交互に繰り返す燃焼方式とＮＯｘ吸蔵還元触媒を用いた浄化方法は、ガソリン乗用車の排ガス処理に用いられている三元触媒が使用できないような高濃度の酸素雰囲気中でも２５０℃付近から６００℃付近に渡ってＮＯｘを浄化できるという利点を持つが、２００℃付近以下でのＮＯｘ浄化は非常に困難であるという問題があり、また、排ガス中の水分及び少量のＳＯｘによってＮＯｘ吸蔵剤が著しく劣化するので、定期的な高温処理による触媒再生が必要であるという問題がある。これは、ＮＯｘ吸蔵還元触媒の化学的性質に原因がある。リーンバーン雰囲気でＮＯ２を吸収するためのＮＯｘ吸蔵剤は、強塩基性のアルカリ金属やアルカリ土類金属の酸化物、水酸化物、炭酸塩等であるので、ＮＯ２もしくは硝酸はこれらの金属化合物とマイルドな温度で容易に反応して硝酸塩として吸収される。リッチバーン雰囲気では、これらの硝酸塩が分解して元の金属化合物と遊離のＮＯ２を発生する。そのため排ガスの処理温度はＮＯｘ吸蔵剤である金属化合物の硝酸塩の分解温度に完全に依存している。公知のＮＯｘ吸蔵剤の分解温度は２５０℃以上であり、２００℃以下で作動するような金属化合物は知られていない。また、上記金属化合物は水溶性でありＳＯｘとも容易に反応して不活性な硫酸塩になるからである。
On the other hand, a three-way catalyst cannot be used for exhaust NOx treatment of small diesel vehicles such as diesel passenger cars. Because the air-fuel ratio is more than several times the air-fuel ratio of gasoline (diesel fuel combustion is lean burn), the oxygen concentration in diesel exhaust gas is usually over 5% and contains almost no reducing substances. It is. For the same reason, it is difficult to purify the exhaust gas from lean burn gasoline vehicles with a three-way catalyst. Currently, a so-called NOx occlusion reduction catalyst in which a NOx occlusion agent is added to a platinum group catalyst as a catalyst has been studied for the exhaust NOx treatment of lean burn gasoline vehicles and small diesel vehicles (see Patent Document 3). This method uses a combustion system in which the internal combustion engine alternately repeats lean burn and rich burn, absorbs lean burn exhaust NOx with a NOx storage agent, releases the absorbed NOx in a rich burn atmosphere, and releases the released NOx with rich burn exhaust gas. It is based on the idea of reducing with a platinum group catalyst using a large amount of reducing substances such as carbon monoxide, hydrogen and hydrocarbons present in the fuel or rich burn exhaust gas supplied therein. The combustion method that repeats lean burn and rich burn alternately and the purification method using NOx occlusion reduction catalyst are around 250 ° C even in a high-concentration oxygen atmosphere where the three-way catalyst used for exhaust gas treatment of gasoline passenger cars cannot be used. Has the advantage of being able to purify NOx over about 600 ° C., but there is a problem that NOx purification at about 200 ° C. or lower is very difficult, and the NOx occlusion agent due to moisture in the exhaust gas and a small amount of SOx Has a problem that catalyst regeneration by periodic high-temperature treatment is necessary. This is due to the chemical nature of the NOx storage reduction catalyst. NOx occlusion agents for absorbing NO 2 in a lean burn atmosphere are strongly basic alkali metal or alkaline earth metal oxides, hydroxides, carbonates, etc., so NO 2 or nitric acid is one of these metals. It easily reacts with compounds at mild temperatures and is absorbed as nitrate. In a rich burn atmosphere, these nitrates decompose to generate the original metal compound and free NO 2 . Therefore, the treatment temperature of the exhaust gas completely depends on the decomposition temperature of the nitrate of the metal compound that is the NOx storage agent. The decomposition temperature of the known NOx storage agent is 250 ° C. or higher, and no metal compound that operates at 200 ° C. or lower is known. Further, the metal compound is water-soluble and easily reacts with SOx to become an inactive sulfate.
ところで、国内ではディーゼル乗用車の排出する排ガスの温度は過渡走行時でおよそ１２０℃〜２００℃であり安定走行時でおよそ２００℃〜４００℃であるが、排出されるＮＯｘの約８０％が過渡走行時に排出されている。
以上のことから、ディーゼル乗用車の排ガス処理に要求される触媒は、上記１２０℃〜２００℃の低温領域のリーンバーン排ＮＯｘに対して高活性を有する触媒であることが望まれているが、現在の所、２５０℃以下のリーンバーン排ＮＯｘに対して有効な排ＮＯｘ浄化方法は見出されていない。また、低温から中温領域でのＮＯｘ浄化の大部分が、非常に大きな温暖化係数をもつ一酸化二窒素（Ｎ２Ｏ）の段階で止まっているという問題も解決されていない。
By the way, in Japan, the temperature of exhaust gas discharged from diesel passenger cars is approximately 120 ° C. to 200 ° C. during transient travel and approximately 200 ° C. to 400 ° C. during stable travel, but about 80% of the NOx discharged is transient travel. Sometimes discharged.
From the above, the catalyst required for exhaust gas treatment of diesel passenger cars is desired to be a catalyst having high activity with respect to the lean burn exhaust NOx in the low temperature range of 120 ° C. to 200 ° C. However, no effective exhaust NOx purification method has been found for lean burn exhaust NOx below 250 ° C. Moreover, the problem that most of NOx purification in the low temperature to medium temperature region stops at the stage of dinitrogen monoxide (N 2 O) having a very large warming coefficient has not been solved.
一般に、工業的な触媒は多孔性材料に担持した状態で使用されることが多い。多孔性材料の細孔は、ＩＵＰＡＣ（国際純正及び応用化学連合）によると、細孔直径が２ｎｍ以下のミクロ細孔、２〜５０ｎｍのメソ細孔、及び５０ｎｍ以上のマクロ細孔に分類されている。ミクロからメソの範囲にわたる広い分布をもつような単一の多孔性材料は活性炭以外には知られていない。
近年、細孔径が数ｎｍの細孔が規則的に配列し、比表面積が４００〜１１００ｍ２／ｇという非常に大きな値を有するシリカ、アルミナ、及びシリカアルミナ系のメソポーラス分子篩が開発された。これらは、例えば、特許文献１、２、及び３等に開示されており、細孔の細孔配列があたかも結晶性物質の原子配列に類似していることから結晶性メソポーラス分子篩と命名されている。
In general, industrial catalysts are often used in a state where they are supported on a porous material. The pores of the porous material are classified into micropores with a pore diameter of 2 nm or less, mesopores of 2 to 50 nm, and macropores of 50 nm or more according to IUPAC (International Pure and Applied Chemical Association). Yes. No single porous material other than activated carbon has a wide distribution ranging from the micro to meso range.
In recent years, silica, alumina, and silica-alumina-based mesoporous molecular sieves have been developed in which pores having a pore size of several nm are regularly arranged and the specific surface area has a very large value of 400 to 1100 m 2 / g. These are disclosed in, for example, Patent Documents 1, 2, and 3, and are named crystalline mesoporous molecular sieves because the pore arrangement of pores is similar to the atomic arrangement of crystalline substances. .
触媒反応は表面反応であるので触媒の比表面積が大きいほど触媒活性が高い。また、触媒を担持するための担体は比表面積が大きいほど触媒活性を発現しやすい。このような観点から自動車用三元触媒をみると、支持体としてのモノリス成形体は成形体の断面が網目状で、軸方向に平行に互いに薄い壁によって仕切られたガス流路を設けている成形体であり、比表面積が約０．２ｍ２／ｇ、担体としてのアルミナ粒子の比表面積が１１０〜３４０ｍ２／ｇであり、触媒の比表面積は粒径から２０〜４０ｍ２／ｇ程度であると推定される。したがって、従来の触媒粒子の粒径よりも一桁から二桁小さいナノサイズの触媒粒子を上記のようなメソポーラス材料の細孔内に担持することによって触媒の表面積は従来の三元触媒の１０２〜１０４倍大きくなるので、これをモノリス成形体に塗布することによって自動車排ガスに対する触媒活性の向上を図ることが考えられ、この考えは、例えば、特許文献５〜１０に開示されている。しかし、ディーゼル乗用車等が排出する１２０℃〜２００℃付近の低温排ＮＯｘを効果的に除去することは困難であった。 Since the catalytic reaction is a surface reaction, the larger the specific surface area of the catalyst, the higher the catalytic activity. Further, the carrier for supporting the catalyst is more likely to exhibit the catalytic activity as the specific surface area is larger. From this point of view, when looking at a three-way catalyst for automobiles, the monolith molded body as a support has a mesh-shaped cross section and is provided with gas flow paths partitioned by thin walls parallel to each other in the axial direction. It is a molded body, the specific surface area is about 0.2 m 2 / g, the specific surface area of alumina particles as a support is 110 to 340 m 2 / g, and the specific surface area of the catalyst is about 20 to 40 m 2 / g from the particle size. Presumed to be. Therefore, the surface area of the catalyst is 10 2 of that of the conventional three-way catalyst by supporting the nano-sized catalyst particles that are one to two orders of magnitude smaller than the particle diameter of the conventional catalyst particles in the pores of the mesoporous material. since 10 becomes 4 times larger, which is believed to enhance the catalytic activity for automotive exhaust by applying monolith forming body, this idea, for example, disclosed in Patent Document 5 to 10. However, it has been difficult to effectively remove low-temperature exhaust NOx around 120 ° C. to 200 ° C. discharged by diesel passenger cars and the like.
本発明の目的は、上記の事情に鑑み、従来困難であった低温領域のリーンバーン排ＮＯｘを効率的に浄化するための新規触媒を用いた排ガス浄化方法を提供することである。 In view of the above circumstances, an object of the present invention is to provide an exhaust gas purification method using a novel catalyst for efficiently purifying lean burn exhaust NOx in a low temperature region, which has been difficult in the past.
本発明者らは、上記の目的を達成するために鋭意研究を重ねた結果、ＮＯｘ吸着剤とＮＯｘ酸化還元触媒から成るＮＯｘ吸着酸化還元触媒がリーンバーン排ＮＯｘに対して非常に有効であることを見いだし、この知見に基づいて本発明を完成させるに至った。
すなわち、本発明は、
（１）ＮＯｘ吸着剤とＮＯｘ酸化還元触媒から成るＮＯｘ吸着酸化還元触媒をリーンバーンとリッチバーンを交互に繰り返す内燃機関の排ガス浄化のために用いる排ガス浄化方法において、
該ＮＯｘ吸着剤が、窒化炭素化合物、 炭窒化ホウ素化合物、及びチタンオキシナイトライド化合物から選ばれた少なくとも１種類の化合物であり、
又、 該ＮＯｘ酸化還元触媒がメソポーラス材料に白金主体の触媒を担持したメソポーラス白金触媒である
ことを特徴とする排ガス浄化方法、
に関する。
As a result of intensive studies to achieve the above object, the present inventors have found that a NOx adsorption redox catalyst comprising a NOx adsorbent and a NOx redox catalyst is very effective for lean burn exhaust NOx. As a result, the present invention has been completed based on this finding.
That is, the present invention
(1) In an exhaust gas purification method using an NOx adsorption redox catalyst comprising a NOx adsorbent and a NOx redox catalyst for exhaust gas purification of an internal combustion engine in which lean burn and rich burn are alternately repeated ,
The NOx adsorbent is at least one compound selected from a carbon nitride compound, a boron carbonitride compound, and a titanium oxynitride compound;
The exhaust gas purification method, wherein the NOx oxidation-reduction catalyst is a mesoporous platinum catalyst in which a platinum-based catalyst is supported on a mesoporous material ,
About.
本発明の排ガス浄化方法は、従来達成できなかったリーンバーン排ＮＯｘ処理を低温領域でも極めて効率よく行うことができる。例えば、三元触媒では酸素濃度１０％の雰囲気下におけるＮＯｘはほとんど劣化してしまうため浄化できないが、本発明である炭化窒素と白金触媒から成る排ガス浄化用触媒を用いると、リーンバーンとリッチバーンを交互に繰り返す燃焼方式の排ガスに対してＮＯｘの６０％以上を１８０℃〜５００℃において浄化できる。また、アルコールを還元剤として用いるとＮＯｘ浄化の９０％以上が窒素の段階まで還元されるという特長をもつ。 The exhaust gas purification method of the present invention can perform lean burn exhaust NOx treatment, which could not be achieved conventionally, very efficiently even in a low temperature region. For example, in a three-way catalyst, NOx in an atmosphere with an oxygen concentration of 10% is almost deteriorated and cannot be purified. However, when an exhaust gas purification catalyst comprising nitrogen carbide and a platinum catalyst according to the present invention is used, lean burn and rich burn It is possible to purify 60% or more of NOx at 180 ° C. to 500 ° C. with respect to the exhaust gas of the combustion system that alternately repeats. Further, when alcohol is used as a reducing agent, 90% or more of the NOx purification is reduced to the nitrogen level.
以下、本発明を詳細に説明する。
本発明は、リーンバーンとリッチバーンを交互に繰り返す内燃機関が排出するＮＯｘを浄化するために有効な新規触媒を用いる排ガス浄化方法であり、具体的には、ＮＯｘ吸着剤とＮＯｘ酸化還元触媒から成るＮＯｘ吸着酸化還元触媒を用いる排ガス浄化方法である。該ＮＯｘ吸着剤の役割は、リーンバーン雰囲気でＮＯｘ（主としてＮＯ２）を吸着し、該吸着ＮＯｘをリッチバーン雰囲気で脱着することであり、又、ＮＯｘ酸化還元触媒の役割は、リーンバーン雰囲気でＮＯをＮＯ２に酸化し、リッチバーン雰囲気でＮＯｘを還元
処理することである。ＮＯｘ吸着剤の吸着と脱着の性質は、活性炭などの吸着剤の性質と同様、吸着物質の濃度には依存するが温度にはあまり依存しないので、リーンバーン雰囲気では室温付近からＮＯｘの吸着が始まり、ＮＯｘ酸化還元触媒による処理によってＮＯｘ濃度が低くなっているリッチバーン雰囲気では容易にＮＯｘを脱着することができる。脱着ＮＯｘはリッチバーン雰囲気でＮＯｘ酸化還元触媒によって還元処理される。したがって、本発明浄化方法が有効な排ガス温度は、ＮＯｘ酸化還元触媒の活性温度にほとんど依存しており、その下限温度はおよそ１６０℃である。また、ＮＯｘ吸着剤は、排ガス中に少量含まれるＳＯｘも吸着するがリッチバーン雰囲気で容易に脱着するのでＳＯｘによる触媒被毒はほとんどない。
Hereinafter, the present invention will be described in detail.
The present invention is an exhaust gas purification method using a novel catalyst effective for purifying NOx emitted from an internal combustion engine that alternately repeats lean burn and rich burn. Specifically, the present invention relates to a NOx adsorbent and a NOx redox catalyst. An exhaust gas purification method using the NOx adsorption redox catalyst. The role of the NOx adsorbent is to adsorb NOx (mainly NO 2 ) in a lean burn atmosphere, and to desorb the adsorbed NOx in a rich burn atmosphere, and the role of the NOx redox catalyst is in a lean burn atmosphere. NO is oxidized to NO 2 and NOx is reduced in a rich burn atmosphere. The adsorption and desorption properties of NOx adsorbent, like the properties of adsorbents such as activated carbon, depend on the concentration of the adsorbent but not on the temperature, so NOx adsorption begins near room temperature in a lean burn atmosphere. NOx can be easily desorbed in a rich burn atmosphere in which the NOx concentration is lowered by the treatment with the NOx oxidation-reduction catalyst. Desorbed NOx is reduced by a NOx redox catalyst in a rich burn atmosphere. Therefore, the exhaust gas temperature at which the purification method of the present invention is effective largely depends on the activation temperature of the NOx redox catalyst, and its lower limit temperature is approximately 160 ° C. The NOx adsorbent also adsorbs a small amount of SOx contained in the exhaust gas, but it is easily desorbed in a rich burn atmosphere, so there is almost no catalyst poisoning by SOx.
本発明におけるＮＯｘ吸着剤としては、窒化炭素化合物、炭窒化ホウ素化合物、窒化ホウ素、炭窒化ケイ素、炭化ホウ素、窒化物、炭化物、ホウ化物、活性炭、及びゼオライトを挙げることができる。窒化炭素化合物としては、トリアジン環の１，３，５位がＮＨ基で結合した平面構造のカーボンナイトライド、及びトリストリアジン環の１，５，９位がＮＨ基で結合した平面構造のカーボンナイトライドを挙げることができる。炭窒化ホウ素化合物としては、黒鉛類似の構造をもつカーボンボロンナイトライドを挙げることができる。窒化物としては、窒化ケイ素、窒化酸化ケイ素（＝シリコンオキシナイトライド）、窒化アルミニウム、遷移金属窒化物（窒化チタン、窒化酸化チタン、窒化バナジウム、窒化ジルコニウム、窒化クロム、窒化タングステン、窒化モリブデン、窒化鉄、窒化マンガン、窒化コバルト、窒化ニッケルの総称）、窒化スカンジウム、窒化ハフニウム、窒化ニオブ、窒化タンタル、及び窒化セリウム等の希土類元素の窒化物、を挙げることができる。ゼオライトとしては、天然ゼオライト及び合成ゼオライト（ゼオライトＡ、ゼオライトＸ、ゼオライトＹ、ゼオライトＬ、モルデナイト、ＺＳＭ−５、及び他の元素から成るゼオライト様の性質・構造をもつ化合物の総称）を挙げることができる。これらの中で、窒化炭素化合物、炭窒化ホウ素化合物、ゼオライト、及び遷移金属窒化物が好ましい。窒化炭素化合物、及び炭窒化ホウ素化合物を構成する窒素原子は孤立電子対をもつので、これがＮＯｘの吸着サイトであると考えられる。遷移金属窒化物は、結合電子密度が窒素原子のほうに偏っているので、ＮＯｘが吸着しやすいものと考えられる。また、ゼオライトはアンモニア等を吸着する陽イオン交換能を持つので、その陽イオンにＮＯ２が吸着するものと考えられる。また、これらの化合物に配位結合やイオン結合によって陽イオンを導入したものもＮＯｘ吸着性に優れているので好ましい。上記のＮＯｘ吸着剤がＮＯｘを吸着する性質をもつことは、ＮＯｘ存在下での材料の質量増加を測定することによって実証される。またＮＯｘの吸着であってＮＯｘの吸収ではないことは、吸着後の材料の赤外吸収スペクトルがＮＯｘの特性基振動数を示すが硝酸イオンあるいは亜硝酸イオンの特性基振動数を示さないことから実証される。 Examples of the NOx adsorbent in the present invention include carbon nitride compounds, boron carbonitride compounds, boron nitride, silicon carbonitride, boron carbide, nitride, carbide, boride, activated carbon, and zeolite. As the carbon nitride compound, a carbon nitride having a planar structure in which the 1,3,5 positions of the triazine ring are bonded with NH groups, and a carbon nitride having a planar structure in which the 1,5,9 positions of the tristriazine ring are bonded with NH groups are used. Ride can be mentioned. Examples of the boron carbonitride compound include carbon boron nitride having a structure similar to graphite. As nitrides, silicon nitride, silicon nitride oxide (= silicon oxynitride), aluminum nitride, transition metal nitride (titanium nitride, titanium nitride oxide, vanadium nitride, zirconium nitride, chromium nitride, tungsten nitride, molybdenum nitride, nitride) Examples thereof include nitrides of rare earth elements such as iron, manganese nitride, cobalt nitride, nickel nitride), scandium nitride, hafnium nitride, niobium nitride, tantalum nitride, and cerium nitride. Examples of zeolite include natural zeolite and synthetic zeolite (generic name for zeolite A, zeolite X, zeolite Y, zeolite L, mordenite, ZSM-5, and other compounds having zeolite-like properties and structures). it can. Of these, carbon nitride compounds, boron carbonitride compounds, zeolites, and transition metal nitrides are preferred. Since the nitrogen atom which comprises a carbon nitride compound and a boron carbonitride compound has a lone pair, it is thought that this is a NOx adsorption site. The transition metal nitride is considered to easily adsorb NOx because the bond electron density is biased toward nitrogen atoms. Further, since zeolite has a cation exchange ability to adsorb ammonia and the like, it is considered that NO 2 is adsorbed to the cation. In addition, those in which a cation is introduced into these compounds by a coordination bond or an ionic bond are preferable because they are excellent in NOx adsorption. That the NOx adsorbent has the property of adsorbing NOx is demonstrated by measuring the mass increase of the material in the presence of NOx. Also, it is NOx adsorption and not NOx absorption because the infrared absorption spectrum of the adsorbed material shows NOx characteristic group frequency but not nitrate ion or nitrite ion characteristic group frequency. Proven.
本発明におけるＮＯｘ酸化還元触媒としては公知の遷移金属酸化物触媒及び白金族触媒を用いることができる。遷移金属酸化物触媒の遷移元素としては、周期律表における３族〜１１族の元素が挙げられるが、これらの中でバナジウム、クロム、マンガン、鉄、コバルト、ニッケル、銅、亜鉛、モリブデン、タングステン、レニウム、が好ましく、中でも鉄、コバルト、タングステンが最も好ましい。白金族触媒の白金族元素とは、ルテニウム、ロジウム、パラジウム、オスミウム、イリジウム、及び白金の６元素の総称であるが、これらの中で、ロジウム、パラジウム、イリジウム、白金が好ましく、中でも白金が最も好ましい。通常、本発明では、白金主体の触媒を用いるが、その理由は、触媒の主成分である白金が排ＮＯｘの主成分であるＮＯをＮＯ２に酸化する能力が高く、ＮＯ２を還元剤によってＮ２Ｏ及び窒素に還元する能力が高く、高濃度の酸素雰囲気中でも化学的に安定であるからであり、又、白金族元素の中では白金が比較的低温高活性であるからでもある。白金主体の触媒に異なる機能をもつ助触媒的成分を添加することによってシナジー効果による触媒性能の向上をはかることもできる。このような成分として、例えば、１族〜３族の元素を挙げることができ、これらの中で、アルカリ金属、又は、アルカリ土類金属の酸化物、水酸化物、炭酸塩、及び重炭酸塩などは、還元剤としてアルコールを用いる場合、アルコールの改質反応を促進する効果をもつので好ましい。これらの助触媒的成分の添加質量は、通常、白金の０．０１倍から１００倍程度であるが、必要に応じて１００倍以上であってもよい。 As the NOx redox catalyst in the present invention, known transition metal oxide catalysts and platinum group catalysts can be used. Examples of the transition element of the transition metal oxide catalyst include elements of Group 3 to Group 11 in the periodic table. Among these, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, molybdenum, tungsten , Rhenium, and iron, cobalt, and tungsten are most preferable. The platinum group element of the platinum group catalyst is a general term for the six elements of ruthenium, rhodium, palladium, osmium, iridium, and platinum. Of these, rhodium, palladium, iridium, and platinum are preferred, and platinum is the most preferred. preferable. Usually, in the present invention, a platinum-based catalyst is used. The reason is that platinum, which is the main component of the catalyst, has a high ability to oxidize NO, which is the main component of exhaust NOx, into NO 2 , and NO 2 is reduced by a reducing agent. This is because it has a high ability to reduce to N 2 O and nitrogen and is chemically stable even in a high-concentration oxygen atmosphere, and also because platinum is relatively active at a relatively low temperature among platinum group elements. By adding a co-catalytic component having a different function to the platinum-based catalyst, the catalyst performance can be improved by the synergy effect. Examples of such components include Group 1 to Group 3 elements, among which alkali metal or alkaline earth metal oxides, hydroxides, carbonates, and bicarbonates. When alcohol is used as the reducing agent, it is preferable because it has an effect of promoting the alcohol reforming reaction. The added mass of these promoter components is usually about 0.01 to 100 times that of platinum, but may be 100 times or more as required.
本発明におけるＮＯｘ吸着酸化還元触媒は、通常、ＮＯｘ吸着剤とＮＯｘ酸化還元触媒を混合した所謂混合触媒として用いる。ＮＯｘ吸着剤とＮＯｘ酸化還元触媒の混合比はＮＯｘ除去条件に応じて任意に設定することができる。ＮＯｘ吸着剤は、通常、そのまま用いることができるが、ＮＯｘ酸化還元触媒は、メソポーラス材料に触媒を担持した所謂メソポーラス触媒の形態で用いることが好ましい。
メソポーラス触媒の担体として用いるメソポーラス材料は、高比表面積を有し細孔径がナノサイズであるので、そこに担持される触媒の比表面積を飛躍的に高められること、触媒を細孔内に担持することで触媒粒子の再凝集を抑制し触媒の均一高分散を図れること、などの優れた効果がある。メソポーラス材料の比表面積は、特別な事情がない限り高ければ高いほどよい。本発明に用いることのできるメソポーラス材料の比表面積は１００〜３０００ｍ２／ｇであり、好ましくは２００〜２０００ｍ２／ｇ、さらに好ましくは、４００〜２０００ｍ２／ｇである。比表面積が担持触媒の触媒性能を引き出す上で１００ｍ２／ｇ以上であることが好ましい。一方、材料強度上の面からは比表面積が３０００ｍ２／ｇ以下であることが好ましい。また、本発明におけるメソポーラス材料の細孔の大部分は、細孔径（直径表示）が１〜５０ｎｍの範囲にあり、好ましくは２〜２０ｎｍの範囲にあり、より好ましくは２〜１０ｎｍの範囲にある。ここでいう細孔の大部分とは１〜５０ｎｍの細孔が占める細孔容積が全細孔容積の６０％以上であることをいう。細孔径が１ｎｍ未満であっても触媒の担持は可能であるが還元剤の流通や不純物等による汚染の影響を考えると１ｎｍ以上が好ましい。５０ｎｍを越えると分散担持された触媒が水熱高温条件などによるシンタリング（＝燒結）によって巨大粒子に成長しやすくなるので５０ｎｍ以下が好ましい。メソポーラス材料の細孔に担持される触媒の粒径は、細孔径とほぼ同程度ないしそれ以下であるので、前記の細孔径の範囲は、高活性を発現する触媒の粒径範囲とも一致している。一般に、ナノサイズに微粒化された触媒粒子は、活性を示すエッジ、コーナー、ステップなどの高次数の結晶面を多量にもつので、触媒活性が著しく向上するだけでなく、バルクでは触媒活性を示さないような不活性金属でも予期しなかった触媒活性を発現する場合があることが知られている。したがって、触媒能力の観点からは触媒は小さいほど好ましいのであるが、反面、微粒化による表面酸化、副反応などの好ましくない性質もでてくるので、微粒子の粒子径には最適範囲が存在する。本発明における目的のＮＯｘ浄化処理に対して効果的な活性を示す触媒の平均粒径は１〜５０ｎｍの範囲にあり、１〜２０ｎｍの範囲が好ましく、１〜１０ｎｍの範囲が特に好ましい。
The NOx adsorption redox catalyst in the present invention is usually used as a so-called mixed catalyst in which a NOx adsorbent and a NOx redox catalyst are mixed. The mixing ratio of the NOx adsorbent and the NOx redox catalyst can be arbitrarily set according to the NOx removal conditions. The NOx adsorbent can usually be used as it is, but the NOx redox catalyst is preferably used in the form of a so-called mesoporous catalyst in which a catalyst is supported on a mesoporous material.
The mesoporous material used as the support for the mesoporous catalyst has a high specific surface area and a pore size of nano-size, so that the specific surface area of the catalyst supported thereon can be dramatically increased, and the catalyst is supported in the pores. Thus, there are excellent effects such as suppressing reaggregation of the catalyst particles and achieving uniform and high dispersion of the catalyst. The higher the specific surface area of the mesoporous material, the better, unless there are special circumstances. The specific surface area of mesoporous materials that may be used in the present invention is 100~3000m 2 / g, preferably 200-2000 m 2 / g, and more preferably from 400~2000m 2 / g. The specific surface area is preferably 100 m 2 / g or more in order to bring out the catalyst performance of the supported catalyst. On the other hand, in terms of material strength, the specific surface area is preferably 3000 m 2 / g or less. Further, most of the pores of the mesoporous material in the present invention have a pore diameter (diameter display) in the range of 1 to 50 nm, preferably in the range of 2 to 20 nm, more preferably in the range of 2 to 10 nm. . The majority of the pores referred to here means that the pore volume occupied by pores of 1 to 50 nm is 60% or more of the total pore volume. The catalyst can be supported even if the pore diameter is less than 1 nm, but 1 nm or more is preferable in consideration of the influence of contamination due to the flow of the reducing agent and impurities. If it exceeds 50 nm, the dispersion-supported catalyst tends to grow into giant particles by sintering (= sintering) under hydrothermal high temperature conditions and the like. Since the particle size of the catalyst supported in the pores of the mesoporous material is approximately the same as or smaller than the pore size, the above-mentioned pore size range coincides with the particle size range of the catalyst exhibiting high activity. Yes. In general, catalyst particles atomized to nano size have a large number of high-order crystal planes such as edges, corners, and steps showing activity, so that not only catalytic activity is significantly improved but also catalytic activity in the bulk. It is known that even an inert metal such as this may exhibit unexpected catalytic activity. Therefore, the smaller the catalyst, the better from the viewpoint of catalytic ability. However, on the other hand, undesirable properties such as surface oxidation and side reaction due to atomization also appear, so there is an optimum range for the particle size of the fine particles. The average particle diameter of the catalyst exhibiting effective activity for the target NOx purification treatment in the present invention is in the range of 1 to 50 nm, preferably in the range of 1 to 20 nm, and particularly preferably in the range of 1 to 10 nm.
以上のような比表面積と細孔分布を併せ持ったメソポーラス材料としては、シリカ、アルミナ、チタニア、ジルコニア、マグネシア、カルシア、セリア、ニオビア、活性炭、多孔質黒鉛などを挙げることができ、シリカ、アルミナ、チタニア、ジルコニア、マグネシア、カルシア、セリア、活性炭、及びこれらの複合材料が好ましく、シリカ、アルミナ、マグネシア、活性炭、及びこれらの複合材料がさらに好ましい。また、場合によっては多孔質のＮＯｘ吸着剤にＮＯｘ酸化還元触媒を担持した触媒形態であることが好ましく、あるいは多孔質のＮＯｘ吸着剤でＮＯｘ酸化還元触媒をマイクロカプセル化することも好ましい触媒の形態である。 Examples of the mesoporous material having both the specific surface area and the pore distribution as described above include silica, alumina, titania, zirconia, magnesia, calcia, ceria, niobia, activated carbon, porous graphite, and the like. Titania, zirconia, magnesia, calcia, ceria, activated carbon, and a composite material thereof are preferable, and silica, alumina, magnesia, activated carbon, and a composite material thereof are more preferable. In some cases, the catalyst is preferably in the form of a catalyst in which a NOx redox catalyst is supported on a porous NOx adsorbent, or the NOx redox catalyst is preferably microencapsulated with a porous NOx adsorbent. It is.
なお、上記メソポーラス材料の比表面積は、吸脱着の気体として窒素を用いたＢＥＴ窒素吸着法によって測定される値であり、細孔径は、吸脱着の気体として窒素を用いた窒素吸着法によって測定される値でありＢＪＨ法によって求められる１〜２００ｎｍの範囲の細孔分布（微分分布表示）で示される。
メソポーラス材料に白金主体の触媒を担持する時の白金の担持量は０．０１〜２０質量
％であり、好ましくは０．１〜１０質量％であるが、量的な問題がなければ、通常は、１ないし数質量％の担持量で用いる。担持量は２０質量％以上でも可能であるが、担持量が過剰になると反応にほとんど寄与しない細孔深部の触媒が増えるので２０質量％以下が好ましい。触媒活性の観点から０．０１質量％以上が好ましい
The specific surface area of the mesoporous material is a value measured by a BET nitrogen adsorption method using nitrogen as an adsorption / desorption gas, and the pore diameter is measured by a nitrogen adsorption method using nitrogen as an adsorption / desorption gas. This is a pore distribution (differential distribution display) in the range of 1 to 200 nm determined by the BJH method.
When the platinum-based catalyst is supported on the mesoporous material, the supported amount of platinum is 0.01 to 20% by mass, preferably 0.1 to 10% by mass. It is used in a loading amount of 1 to several mass%. The supported amount can be 20% by mass or more, but if the supported amount is excessive, the catalyst in the deep pores that hardly contributes to the reaction increases, so 20% by mass or less is preferable. From the viewpoint of catalytic activity, 0.01% by mass or more is preferable.
本発明の浄化方法では、ＮＯｘの還元剤として一酸化炭素、水素、炭化水素、水蒸気、炭化水素由来の改質ガス、アルコール及びアルコール由来の改質ガス、等の還元性物質を用いることができ、還元剤の供給方法としては、リッチバーンの排ガスに含まれる水素、一酸化炭素、炭化水素、水蒸気を増加する方法、燃料を改質触媒を通して改質後にリッチバーンの排ガスに供給する方法、アルコールを直接的に排ガスに供給する方法、アルコールを改質触媒を通して改質後に排ガスに供給する方法、等を用いることができる。アルコールはガソリンの代替燃料として近年注目されているが、アルデヒド、一酸化炭素、水素等の還元性物質の原料としても用いられている物質であるので、ＮＯｘの還元剤としても利用できる。本発明者等の研究によれば、適切なアルコール用の改質触媒を用いれば、ハイドロカーボンＳＣＲ法で還元剤として機能する低級オレフィンと違って、酸化雰囲気の排ＮＯｘに対して高活性を示すことが見出されている。また、２００℃付近以下から３００℃付近の低温〜中温領域でも還元が窒素の段階まで進むという特長を持つことが見出されている。アルコールとしては、メタノール、エタノール、プロパノール、ブタノール、等の低級アルコールと炭素数５以上のアルコールが有効であるが、これらの中でメタノール、エタノール、プロパノール、ブタノールが還元性に優れているので好ましく、中でもエタノールは、引火性が低く経口毒性も低いのでさらに好ましい。上記のアルコールは、含水アルコールでも有効である。含水アルコールでは、アルコールの水蒸気改質反応を起こすことができる。含水率は、アルコールの改質温度に影響を与えない程度であることが好ましく、通常は１０％程度以内である。還元剤としてアルコール由来の改質ガスを用いる場合には、改質触媒を通して供給されるアルコールの供給量は、排ガス中の酸素濃度にも多少影響されるが、酸素濃度が２０％以下の範囲ではＮＯｘと同程度のモル数から数１０倍程度のモル数であれば特に限定するものではない。また、酸化剤として少量の空気をアルコールに混合してもよい。空気量は、アルコールの部分酸化を起こさせる程度の量であれば特に限定するものではないが、通常は、数倍モル程度以下である。アルコールの改質温度は、アルコールの種類や改質触媒の種類によって適切な温度に設定する。本発明では、通常、１００℃〜５００℃の範囲で行う。改質触媒の加熱は、排熱回収、直接加熱、等の方法によって行うことができる。 In the purification method of the present invention, reducing substances such as carbon monoxide, hydrogen, hydrocarbons, steam, hydrocarbon-derived reformed gas, alcohol and alcohol-derived reformed gas can be used as the NOx reducing agent. As a method of supplying the reducing agent, a method of increasing hydrogen, carbon monoxide, hydrocarbons, and steam contained in the exhaust gas of rich burn, a method of supplying fuel to the exhaust gas of rich burn after reforming through a reforming catalyst, alcohol A method of directly supplying to the exhaust gas, a method of supplying alcohol to the exhaust gas after reforming through a reforming catalyst, and the like can be used. Alcohol has recently attracted attention as an alternative fuel for gasoline. However, since it is a substance that is also used as a raw material for reducing substances such as aldehyde, carbon monoxide, and hydrogen, it can also be used as a reducing agent for NOx. According to the study by the present inventors, when an appropriate reforming catalyst for alcohol is used, it exhibits high activity against exhaust NOx in an oxidizing atmosphere, unlike a lower olefin that functions as a reducing agent in the hydrocarbon SCR method. It has been found. It has also been found that the reduction proceeds to the nitrogen stage even in the low to medium temperature range from about 200 ° C. or lower to about 300 ° C. As the alcohol, lower alcohols such as methanol, ethanol, propanol, and butanol and alcohols having 5 or more carbon atoms are effective. Among these, methanol, ethanol, propanol, and butanol are preferable because of their excellent reducibility, Of these, ethanol is more preferred because of its low flammability and low oral toxicity. The above alcohol is also effective as a hydrous alcohol. Hydrous alcohol can cause a steam reforming reaction of alcohol. The water content is preferably such that it does not affect the reforming temperature of the alcohol, and is usually within about 10%. When alcohol-derived reformed gas is used as the reducing agent, the amount of alcohol supplied through the reforming catalyst is somewhat affected by the oxygen concentration in the exhaust gas, but the oxygen concentration is within a range of 20% or less. The number of moles is not particularly limited as long as it is from the same number of moles as NOx to several tens of moles. Moreover, you may mix a small amount of air with alcohol as an oxidizing agent. The amount of air is not particularly limited as long as it is an amount that causes partial oxidation of alcohol, but is usually about several moles or less. The reforming temperature of the alcohol is set to an appropriate temperature depending on the type of alcohol and the type of reforming catalyst. In the present invention, it is usually carried out in the range of 100 ° C to 500 ° C. The reforming catalyst can be heated by a method such as exhaust heat recovery or direct heating.
本発明で用いるメソポーラス材料の製造は、従来の方法である界面活性剤のミセルをテンプレートとして用いるゾル−ゲル法を応用することによって所用の材料を製造することができる。メソポーラス材料の前駆物質には、メソポーラスシリカの場合、通常、テトラメトキシシラン、テトラエトキシシラン、テトラ−ｉ−プロポキシシラン、テトラ−ｎ−プロポキシシラン、テトラ−ｉ−ブトキシシラン、テトラ−ｎ−ブトキシシラン、テトラ−ｓｅｃ−ブトキシシラン、テトラ−ｔ−ブトキシシラン等のアルコキシドを用いる。メソポーラスアルミナ、チタニア、ジルコニア、マグネシア、カルシア、セリア、ニオビアについても、通常、アルコキシドを用いて製造することができる。ミセル形成の界面活性剤は、例えば、長鎖のアルキルアミン、長鎖の４級アンモニウム塩、長鎖のアルキルアミンＮ−オキシド、長鎖のスルホン酸塩、ポリエチレングリコールアルキルエーテル、ポリエチレングリコール脂肪酸エステル等のいずれであってもよい。溶媒として、通常、水、アルコール類、ジオールの１種以上が用いられるが、水系溶媒が好ましい。反応系に金属への配位能を有する化合物を少量添加すると反応系の安定性を著しく高めることができる。このような安定剤としては、アセチルアセトン、テトラメチレンジアミン、エチレンジアミン四酢酸、ピリジン、ピコリンなどの金属配位能を有する化合物が好ましい。前駆物質、界面活性剤、溶媒及び安定剤からなる反応系の組成は、前駆物質のモル比が０．０１〜０．６０、好ましくは０．０２〜０．５０、前駆物質／界面活性剤のモル比が１〜３０、好ましくは１〜１０、溶媒／界面活性剤のモル比が１〜１０００、好ましくは５〜５００、安定化剤／前駆物質のモル比が０．０１〜１．０、好ましくは０．２〜０．６である。反応温度は、２０〜１８０℃、好ましくは２０〜１００℃の範囲である。反応時間は５〜１００時間、好ましくは１０〜５０時間の範囲である。反応生成物は通常、濾過により分離し、十分に水洗、乾燥後、５００〜１０００℃の高温焼成によってテンプレートを熱分解除去し、メソポーラス材料を得ることができる。必要に応じて、焼成前に界面活性剤をアルコールなどで抽出することもできる。 The mesoporous material used in the present invention can be produced by applying a sol-gel method using a surfactant micelle as a template, which is a conventional method. In the case of mesoporous silica, the precursor of mesoporous material is usually tetramethoxysilane, tetraethoxysilane, tetra-i-propoxysilane, tetra-n-propoxysilane, tetra-i-butoxysilane, tetra-n-butoxysilane. An alkoxide such as tetra-sec-butoxysilane or tetra-t-butoxysilane is used. Mesoporous alumina, titania, zirconia, magnesia, calcia, ceria and niobia can also be usually produced using an alkoxide. Examples of micelle-forming surfactants include long-chain alkylamines, long-chain quaternary ammonium salts, long-chain alkylamine N-oxides, long-chain sulfonates, polyethylene glycol alkyl ethers, polyethylene glycol fatty acid esters, etc. Any of these may be used. As the solvent, one or more of water, alcohols, and diols are usually used, and an aqueous solvent is preferable. When a small amount of a compound having a coordination ability to metal is added to the reaction system, the stability of the reaction system can be remarkably enhanced. As such a stabilizer, compounds having metal coordination ability such as acetylacetone, tetramethylenediamine, ethylenediaminetetraacetic acid, pyridine, and picoline are preferable. The composition of the reaction system comprising the precursor, surfactant, solvent and stabilizer is such that the molar ratio of the precursor is 0.01 to 0.60, preferably 0.02 to 0.50, and the precursor / surfactant The molar ratio is 1-30, preferably 1-10, the solvent / surfactant molar ratio is 1-1000, preferably 5-500, the stabilizer / precursor molar ratio is 0.01-1.0, Preferably it is 0.2-0.6. The reaction temperature is in the range of 20 to 180 ° C, preferably 20 to 100 ° C. The reaction time is 5 to 100 hours, preferably 10 to 50 hours. The reaction product is usually separated by filtration, sufficiently washed with water, dried, and then thermally decomposed and removed from the template by high-temperature baking at 500 to 1000 ° C. to obtain a mesoporous material. If necessary, the surfactant can be extracted with alcohol or the like before firing.
本発明で用いるメソポーラス触媒は、例えば、イオン交換法又は含浸法によって製造することができる。これらの二つの方法は、担体への触媒の沈着化について、イオン交換法が担体表面のイオン交換能を利用し、含浸法が担体のもつ毛管作用を利用しているという違いはあるが、基本的なプロセスはほとんど同じである。すなわち、強塩基性のメソポーラス材料を触媒原料の水溶液に浸した後、濾過、乾燥し、必要に応じて水洗を行い、還元剤で還元処理することによって製造することができる。 The mesoporous catalyst used in the present invention can be produced, for example, by an ion exchange method or an impregnation method. These two methods are different in that the catalyst is deposited on the support, although the ion exchange method uses the ion exchange capacity of the support surface and the impregnation method uses the capillary action of the support. The general process is almost the same. That is, it can be produced by immersing a strongly basic mesoporous material in an aqueous solution of the catalyst raw material, followed by filtration, drying, washing with water as necessary, and reduction treatment with a reducing agent.
白金の触媒原料としては、例えば、Ｈ２ＰｔＣｌ４、（ＮＨ４）２ＰｔＣｌ４、Ｈ２ＰｔＣｌ６、（ＮＨ４）２ＰｔＣｌ６、Ｐｔ（ＮＨ３）４（ＮＯ３）２、Ｐｔ（ＮＨ３）４（ＯＨ）２、ＰｔＣｌ４、白金のアセチルアセトナート、等を用いることができる。必要に応じて助触媒的成分を添加した触媒は、例えば、助触媒的成分の硝酸塩、硫酸塩、炭酸塩、酢酸塩などの水溶性塩類を白金触媒原料に混合して同様にして製造することができる。触媒活性成分の還元剤としては、水素、ヒドラジン水溶液、ホルマリン、等を用いることができる。還元は、それぞれの還元剤について知られている通常の条件で行なえばよい。例えば、水素還元は、ヘリウムなどの不活性ガスで希釈した水素ガス気流下にサンプルを置き、通常、３００〜５００℃で数時間処理することによって行なうことができる。還元後、必要に応じて、不活性ガス気流下５００〜１０００℃で数時間熱処理してもよい。 Examples of the platinum catalyst material include H 2 PtCl 4 , (NH 4 ) 2 PtCl 4 , H 2 PtCl 6 , (NH 4 ) 2 PtCl 6 , Pt (NH 3 ) 4 (NO 3 ) 2 , Pt (NH 3 ) 4 (OH) 2 , PtCl 4 , platinum acetylacetonate, and the like can be used. A catalyst to which a co-catalytic component is added as necessary is manufactured in the same manner by mixing water-soluble salts such as nitrate, sulfate, carbonate, and acetate of the co-catalytic component with the platinum catalyst raw material. Can do. As the reducing agent for the catalytically active component, hydrogen, an aqueous hydrazine solution, formalin, or the like can be used. The reduction may be performed under normal conditions known for each reducing agent. For example, hydrogen reduction can be performed by placing a sample in a hydrogen gas stream diluted with an inert gas such as helium and treating the sample at 300 to 500 ° C. for several hours. After reduction, if necessary, heat treatment may be performed at 500 to 1000 ° C. for several hours under an inert gas stream.
本発明で用いるＮＯｘ吸着酸化還元触媒は、通常、自動車用触媒の支持体として用いられているモノリス成形体に付着させて用いる。モノリス成形体とは、成形体の断面が網目状で、軸方向に平行に互いに薄い壁によって仕切られたガス流路を設けている成形体のことであり、モノリス成形体に触媒を付着させて成る触媒を以下ではモノリス触媒という。成形体の外形は、特に限定するものではないが、通常は、円柱形である。ＮＯｘ吸着酸化還元触媒をモノリス成形体のガス流路内壁に付着させる時の触媒の付着量は、３〜３０質量％が好ましい。担体内部に存在する触媒へのガス拡散の面から３０％未満が好ましい。また、十分な触媒性能を引き出す上で３％以上が好ましい。モノリス成形体への触媒の塗布量相当の付着量は、成形体の０．０３〜３質量％が好ましい。 The NOx adsorption redox catalyst used in the present invention is usually used by adhering to a monolith molded article used as a support for automobile catalysts. A monolith molded body is a molded body in which the molded body has a mesh-like cross section and is provided with gas flow paths partitioned by thin walls parallel to each other in the axial direction. A catalyst is attached to the monolith molded body. Such a catalyst is hereinafter referred to as a monolith catalyst. Although the external shape of a molded object is not specifically limited, Usually, it is a cylindrical shape. The adhesion amount of the catalyst when the NOx adsorption redox catalyst is adhered to the gas flow path inner wall of the monolith molded body is preferably 3 to 30% by mass. It is preferably less than 30% from the viewpoint of gas diffusion to the catalyst existing inside the support. Moreover, 3% or more is preferable in order to draw out sufficient catalyst performance. The adhesion amount corresponding to the coating amount of the catalyst on the monolith molded body is preferably 0.03 to 3% by mass of the molded body.
上記のモノリス触媒は、自動車用三元触媒を付着したモノリス成形体の製造方法に準じて製造することができる。例えば、ＮＯｘ吸着酸化還元触媒とバインダーとしてのコロイダルシリカを、通常、１：（０．０１〜０．２）の質量割合で混合した混合物をつくり、これを水分散することによって通常１０〜５０質量％のスラリーを調整した後、該スラリーにモノリス成形体を浸漬してモノリス成形体のガス流路の内壁にスラリーを付着させ、乾燥後、窒素、ヘリウム、アルゴンなどの不活性雰囲気下５００〜１０００℃で数時間熱処理することによって製造することがきる。コロイダルシリカ以外のバインダーとしては、メチルセルロース、アクリル樹脂、ポリエチレングリコールなどを適宜用いることもできる。あるいは、モノリス成形体にメソポーラス材料を塗布したのち、触媒原料を該メソポーラス材料に含浸し、還元処理、熱処理を行う方法によっても製造することができる。モノリス成形体に付着させるＮＯｘ吸着酸化還元触媒層の厚みは、前記のスラリーを付着させる方法では、通常、１μｍ〜１００μｍであるのが好ましく、１０μｍ〜５０μｍの範囲が特に好ましい。反応ガスの観点から１００μｍ以下が好ましい。触媒性能の劣化を抑制する点から１μｍ以上が好ましい。 Said monolith catalyst can be manufactured according to the manufacturing method of the monolith molded object which adhered the three-way catalyst for motor vehicles. For example, a mixture in which a NOx adsorption redox catalyst and colloidal silica as a binder are usually mixed at a mass ratio of 1: (0.01 to 0.2) is prepared, and this is usually 10 to 50 mass by dispersing in water. % Slurry, the monolith molded body is immersed in the slurry to adhere the slurry to the inner wall of the gas flow path of the monolith molded body, and after drying, under an inert atmosphere such as nitrogen, helium, argon, etc. It can be produced by heat treatment at a temperature of several hours. As a binder other than colloidal silica, methyl cellulose, acrylic resin, polyethylene glycol, or the like can be used as appropriate. Alternatively, it can also be produced by a method in which a mesoporous material is applied to a monolith molded body, and then a catalyst raw material is impregnated in the mesoporous material, followed by reduction treatment and heat treatment. The thickness of the NOx adsorption oxidation-reduction catalyst layer to be adhered to the monolith molded body is usually preferably 1 μm to 100 μm, and particularly preferably 10 μm to 50 μm, in the method for adhering the slurry. 100 μm or less is preferable from the viewpoint of the reaction gas. From the viewpoint of suppressing deterioration of the catalyst performance, 1 μm or more is preferable.
本発明の排ＮＯｘ浄化方法は、自動車、特にディーゼル自動車及びリーンバーンガソリン自動車に搭載することによって、自動車が排出するリーンバーン排ＮＯｘを１６０℃〜３００℃の低温領域において極めて効果的に除去することができ、また、酸素濃度が低い時でも有効であるので、排ガス中の酸素濃度が高いリッチバーンと酸素濃度が低いリーンバーンを交互に行うことができる小型ディーゼルの排ガス浄化処理に用いると、１６０℃〜６００℃の広い温度範囲において効率よく排ＮＯｘを浄化処理できる。また、トラックなどの大型車用の排ＮＯｘ浄化方法としても用いることができる。 The exhaust NOx purification method according to the present invention is mounted on automobiles, particularly diesel automobiles and lean burn gasoline automobiles, and thereby removes lean burn exhaust NOx discharged by automobiles extremely effectively in a low temperature range of 160 ° C to 300 ° C. In addition, since it is effective even when the oxygen concentration is low, when it is used for exhaust gas purification treatment of a small diesel engine that can alternately perform rich burn with high oxygen concentration and lean burn with low oxygen concentration in the exhaust gas, 160 Exhaust NOx can be purified efficiently in a wide temperature range of from ℃ to 600 ℃. It can also be used as a method for purifying exhaust NOx for large vehicles such as trucks.
以下に実施例などを挙げて本発明を具体的に説明する。
比表面積及び細孔分布は、脱吸着の気体として窒素を用い、カルロエルバ社製ソープトマチック１８００型装置によって測定した。比表面積はＢＥＴ法によって求めた。細孔分布は１〜２００ｎｍの範囲を測定し、ＢＪＨ法で求められる微分分布で示した。製造したメソポーラス材料の多くは指数関数的に左肩上がりの分布における特定の細孔直径の位置にピークを示した。このピークを与える細孔直径が細孔径である。
The present invention will be specifically described below with reference to examples.
The specific surface area and pore distribution were measured with a Sorpmatic 1800 type apparatus manufactured by Carlo Elba using nitrogen as a desorption gas. The specific surface area was determined by the BET method. The pore distribution was measured in the range of 1 to 200 nm and indicated by a differential distribution obtained by the BJH method. Many of the produced mesoporous materials peaked at specific pore diameter positions in an exponentially increasing distribution. The pore diameter that gives this peak is the pore diameter.
自動車排ＮＯｘのモデルガスとして、ヘリウム希釈一酸化窒素と酸素の混合ガスを用いた。減圧式化学発光法ＮＯｘ分析計（日本サーモ株式会社製造：モデル４２ｉ−ＨＬ及び４６Ｃ−Ｈ）によって処理前と処理後のガスに含まれるＮＯｘ（ＮＯとＮＯ２の合計）とＮ２Ｏ（ＮＯｘの仲間ではない）の濃度を測定し、ＮＯｘ浄化率と窒素の選択率を、それぞれ式（１）及び式（２）によって算出した。 As a model gas for automobile exhaust NOx, a mixed gas of helium diluted nitric oxide and oxygen was used. The reduced pressure chemiluminescence NOx analyzer (Nippon Thermo Co. preparation: Model 42i-HL and 46C-H) (total of NO and NO 2) NOx contained in the gas before and after treatment by the N 2 O (NOx The NOx purification rate and the nitrogen selectivity were calculated by Equation (1) and Equation (2), respectively.
「製造例１」排ガス浄化用触媒としての三元触媒類似の触媒の合成
０．２１５ｇのＰｔＣｌ４・５Ｈ２Ｏ、０．１０６ｇのＰｄＣｌ２・２Ｈ２Ｏ、及び０．１６２ｇのＲｈ（ＮＯ３）３・２Ｈ２Ｏを２０ｍｌの蒸留水に溶解した水溶液を蒸発皿に入れ、これに１０ｇの活性アルミナ（日揮化学株式会社製造：比表面積２５０ｍ２／ｇ、平均細孔径６．２ｎｍ、粒径２〜３μｍの微粒子）を加え、スチームバスで蒸発乾固した後、真空乾燥機に入れ１００℃で３時間真空乾燥を行った。この試料を石英管に入れヘリウム希釈水素ガス（１０％ｖ／ｖ）気流下５００℃で３時間還元し、貴金属の含有量が約２重量％の触媒を合成した。これを、三元触媒を模した貴金属触媒として比較実験に用いた。
“Production Example 1” Synthesis of a catalyst similar to a three-way catalyst as an exhaust gas purification catalyst 0.215 g of PtCl 4 .5H 2 O, 0.106 g of PdCl 2 .2H 2 O, and 0.162 g of Rh (NO 3 ) 3 · 2H 2 O were placed an aqueous solution prepared by dissolving in distilled water of 20ml evaporation dish, to which 10g of active alumina (Nikki chemical Co., Ltd. producing specific surface area: 250 meters 2 / g, average pore diameter 6.2 nm, particle size 2 to 3 μm fine particles) were added and evaporated to dryness in a steam bath, and then placed in a vacuum dryer and vacuum dried at 100 ° C. for 3 hours. This sample was put in a quartz tube and reduced at 500 ° C. for 3 hours under a helium-diluted hydrogen gas (10% v / v) stream to synthesize a catalyst having a noble metal content of about 2% by weight. This was used in a comparative experiment as a noble metal catalyst simulating a three-way catalyst.
「製造例２」ＮＯｘ吸着剤としての窒化炭素化合物の製造
メラミン１００ｇと塩化亜鉛１００ｇを混合し、磁性皿に入れ、電気炉で６５０℃−１ｈ加熱した。室温に放冷後に取り出した固形物を粉砕し、濃塩酸に入れ１時間沸騰処理し
た。室温に放冷後、減圧濾過、水洗、０．１Ｎ水酸化ナトリウムによる洗浄、水洗、２００℃で真空乾燥を行い、窒化炭素化合物を製造した。元素分析、ＩＲ測定、Ｘ線回折測定、質量分析、等によって、トリアジン環の１，３，５位がＮＨ基で結合した平面構造の窒化炭素化合物であることが同定された。
“Production Example 2” Production of carbon nitride compound as NOx adsorbent 100 g of melamine and 100 g of zinc chloride were mixed, placed in a magnetic dish, and heated at 650 ° C. for 1 h in an electric furnace. The solid matter taken out after cooling to room temperature was pulverized, placed in concentrated hydrochloric acid and boiled for 1 hour. After allowing to cool to room temperature, vacuum filtration, washing with water, washing with 0.1N sodium hydroxide, washing with water, and vacuum drying at 200 ° C. were performed to produce a carbon nitride compound. Elemental analysis, IR measurement, X-ray diffraction measurement, mass spectrometry, and the like identified the carbon nitride compound having a planar structure in which the 1,3,5 position of the triazine ring was bonded with an NH group.
「製造例３」ＮＯｘ吸着剤としての炭窒化ホウ素化合物の製造
ポリアクリロニトリル（旭化成株式会社製造：ＰＡＮホモポリマー）の微粉末１００ｇを約７０℃に加熱し、これに三塩化ホウ素ガスを１時間流通させ反応させた後、窒素気流下５００℃−１ｈ加熱、続いて窒素気流下１０００℃−２時間加熱し揮発性物質を取り除いた。室温に放冷後に取り出した固形物を粉砕し、電気炉に入れ窒素気流下１５００℃−１０時間焼成することによって炭窒化ホウ素を製造した。元素分析、ＩＲ測定、Ｘ線回折測定、Ｘ線光電子分光スペクトル測定、等によって、黒鉛類似構造のカーボンボロンナイトライドＢＣ３Ｎであることが同定された。
“Production Example 3” Production of boron carbonitride compound as NOx adsorbent 100g of fine powder of polyacrylonitrile (manufactured by Asahi Kasei Corporation: PAN homopolymer) is heated to about 70 ° C, and boron trichloride gas is circulated through it for 1 hour. After the reaction, the mixture was heated at 500 ° C. for 1 hour under a nitrogen stream, and then heated at 1000 ° C. for 2 hours under a nitrogen stream to remove volatile substances. Boron carbonitride was produced by pulverizing the solid matter taken out after cooling to room temperature and placing it in an electric furnace and firing at 1500 ° C. for 10 hours in a nitrogen stream. Elemental analysis, IR measurement, X-ray diffraction measurement, X-ray photoelectron spectroscopy measurement, etc. identified the carbon boron nitride BC 3 N having a graphite-like structure.
「製造例４」ＮＯｘ吸着剤としてのゼオライトの製造
ゼオライト（東ソー株式会社製造：ＺＳＭ−５）１００ｇを２Ｌの蒸留水に入れ、これに１モル濃度の硝酸バリウム１０ｇを加え、室温で一昼夜攪拌した。減圧濾過、１００ｍＬの蒸留水で洗浄後、１００℃で真空乾燥することによって、バリウムイオン交換のＺＳＭ−５を製造した。
[Production Example 4] Production of zeolite as NOx adsorbent Zeolite (manufactured by Tosoh Corporation: ZSM-5) 100 g was placed in 2 L of distilled water, 10 g of 1 molar barium nitrate was added thereto, and the mixture was stirred at room temperature overnight. . Barium ion exchanged ZSM-5 was produced by vacuum filtration, washing with 100 mL of distilled water, and vacuum drying at 100 ° C.
「製造例５」ＮＯｘ吸着剤としてのメソポーラス遷移金属窒化物の製造
１リットルのビーカーに、蒸留水３００ｇ、エタノール２４０ｇ、アセチルアセトン１０ｇ、及びドデシルアミン３０ｇを入れ、溶解させた。攪拌下でテトラ−ｔ−ブトキシチタン２０４ｇを滴加して室温で２２時間攪拌した。生成物を濾過、水洗し、１１０℃で５時間温風乾燥した後、空気中で５５０℃−５時間焼成して含有するドデシルアミンを分解除去し、メソポーラスチタニア材料を得た。該メソポーラスチタニア材料を小角Ｘ線回折測定した結果、１本のブロードな回折ピークを示した。また、透過型電気顕微鏡観察の結果、細孔の配列には規則的な配列が観測されず無秩序に分散している状態が観測された。これらの結果から、製造したメソポーラスチタニア材料は非晶性であることが確認された。また、細孔分布及び比表面積測定の結果、約３．０ｎｍの位置に細孔ピークがあり、比表面積が４００ｍ２／ｇ、細孔容積が１．２１ｃｍ３／ｇ、２〜５０ｎｍの細孔が占める容積は１．２０ｃｍ３／ｇであった。次に、上記のメソポーラスチタニア材料１０ｇを石英管に入れ１０００℃に加熱し、アンモニアガス気流下で５時間処理することによってメソポーラスのチタンオキシナイトライド化合物を得た。窒化率は約２０％であった。
[Production Example 5] Production of mesoporous transition metal nitride as NOx adsorbent 300 g of distilled water, 240 g of ethanol, 10 g of acetylacetone, and 30 g of dodecylamine were dissolved in a 1 liter beaker. Under stirring, 204 g of tetra-t-butoxy titanium was added dropwise and stirred at room temperature for 22 hours. The product was filtered, washed with water, dried in warm air at 110 ° C. for 5 hours, and then calcined in air at 550 ° C. for 5 hours to decompose and remove the contained dodecylamine to obtain a mesoporous titania material. As a result of small angle X-ray diffraction measurement of the mesoporous titania material, one broad diffraction peak was shown. Further, as a result of observation with a transmission electric microscope, a regular arrangement was not observed in the arrangement of the pores, and a disordered state was observed. From these results, it was confirmed that the produced mesoporous titania material was amorphous. Moreover, as a result of the pore distribution and specific surface area measurement, there is a pore peak at a position of about 3.0 nm, the specific surface area is 400 m 2 / g, the pore volume is 1.21 cm 3 / g, and the pores are 2 to 50 nm. The volume occupied by was 1.20 cm 3 / g. Next, 10 g of the above mesoporous titania material was put in a quartz tube, heated to 1000 ° C., and treated under an ammonia gas stream for 5 hours to obtain a mesoporous titanium oxynitride compound. The nitriding rate was about 20%.
「製造例６」ＮＯｘ酸化還元触媒としてのメソポーラスシリカに担持した白金触媒の製造
１リットルのビーカーに、蒸留水３００ｇ、エタノール２４０ｇ、及びドデシルアミン３０ｇを入れ、溶解させた。攪拌下でテトラエトキシシラン１２５ｇを加えて室温で２２時間攪拌した。生成物を濾過、水洗し、１１０℃で５時間温風乾燥した後、空気中で５５０℃−５時間焼成して含有するドデシルアミンを分解除去し、メソポーラスシリカ材料を得た。該メソポーラスシリカ材料を小角Ｘ線回折測定した結果、１本のブロードな回折ピークを示した。また、透過型電気顕微鏡観察の結果、細孔の配列には規則的な配列が観測されず無秩序に分散している状態が観測された。これらの結果から、製造したメソポーラスシリカ材料は非晶性であることが確認された。また、細孔分布及び比表面積測定の結果、約３．２ｎｍの位置に細孔ピークがあり、比表面積が９３３ｍ２／ｇ、細孔容積が１．３５ｃｍ３／ｇ、１〜５０ｎｍの細孔が占める容積は１．３４ｃｍ３／ｇであった。蒸留水２０ｇに塩化白金酸Ｈ２ＰｔＣｌ６・６Ｈ２Ｏを０．２６７ｇと硝酸ロジウムＲｈ（ＮＯ３）３・２Ｈ２Ｏを０．００１６ｇ溶解した水溶液を蒸発皿に入れ、これに上記のメソポーラスシリカ材料５ｇを加え、スチームバスで蒸発乾固した後、真空乾燥機に入れ１００℃−３時間真空乾燥を行った。この試料を石英管に入れ、ヘリウム希釈水素ガス（１０
ｖ／ｖ％）気流下５００℃で３時間還元し、白金−ロジウムの担持量が約２質量％の［Ｐｔ−Ｒｈ／メソポーラスシリカ］触媒を合成した。メソポーラス触媒に坦持された白金−ロジウム粒子の平均粒径は約３．０ｎｍであった。
[Production Example 6] Production of platinum catalyst supported on mesoporous silica as NOx oxidation-reduction catalyst In a 1 liter beaker, 300 g of distilled water, 240 g of ethanol, and 30 g of dodecylamine were added and dissolved. While stirring, 125 g of tetraethoxysilane was added and stirred at room temperature for 22 hours. The product was filtered, washed with water, dried with warm air at 110 ° C. for 5 hours, and then calcined in air at 550 ° C. for 5 hours to decompose and remove contained dodecylamine to obtain a mesoporous silica material. As a result of small angle X-ray diffraction measurement of the mesoporous silica material, one broad diffraction peak was shown. Further, as a result of observation with a transmission electric microscope, a regular arrangement was not observed in the arrangement of the pores, and a disordered state was observed. From these results, it was confirmed that the produced mesoporous silica material was amorphous. Moreover, as a result of pore distribution and specific surface area measurement, there was a pore peak at a position of about 3.2 nm, a specific surface area of 933 m 2 / g, a pore volume of 1.35 cm 3 / g, and a pore of 1 to 50 nm. The volume occupied by was 1.34 cm 3 / g. An aqueous solution of chloroplatinic acid H 2 PtCl 6 · 6H 2 O and 0.267g and rhodium nitrate Rh (NO 3) 3 · 2H 2 O were dissolved 0.0016g in distilled water 20g were placed in an evaporating dish, to which the above mesoporous After adding 5 g of a silica material and evaporating to dryness in a steam bath, it was put in a vacuum dryer and vacuum dried at 100 ° C. for 3 hours. This sample is put in a quartz tube and diluted with helium diluted hydrogen gas (10
(v / v%) Reduction was performed at 500 ° C. for 3 hours under an air stream to synthesize a [Pt—Rh / mesoporous silica] catalyst having a platinum-rhodium loading of about 2 mass%. The average particle diameter of the platinum-rhodium particles supported on the mesoporous catalyst was about 3.0 nm.
「製造例７」窒化炭素化合物と［Ｐｔ−Ｒｈ／メソポーラスシリカ］触媒の混合触媒の製造
製造例２の窒化炭素化合物１０ｇと製造例６の［Ｐｔ−Ｒｈ／メソポーラスシリカ］触媒１０ｇを均一に混合することによって、排ガス浄化用触媒を製造した。
「製造例８」炭窒化ホウ素化合物と［Ｐｔ−Ｒｈ／メソポーラスシリカ］触媒の混合触媒の製造
製造例３の炭窒化ホウ素化合物１０ｇと製造例６の［Ｐｔ−Ｒｈ／メソポーラスシリカ］触媒１０ｇを均一に混合することによって、排ガス浄化用触媒を製造した。
[Production Example 7] Production of mixed catalyst of carbon nitride compound and [Pt-Rh / mesoporous silica] catalyst 10 g of carbon nitride compound of Production Example 2 and 10 g of [Pt-Rh / mesoporous silica] catalyst of Production Example 6 were uniformly mixed. Thus, an exhaust gas purification catalyst was produced.
[Production Example 8] Production of mixed catalyst of boron carbonitride compound and [Pt-Rh / mesoporous silica] catalyst 10 g of boron carbonitride compound of Production Example 3 and 10 g of [Pt-Rh / mesoporous silica] catalyst of Production Example 6 The exhaust gas-purifying catalyst was produced by mixing with the above.
「製造例９」ゼオライトと［Ｐｔ−Ｒｈ／メソポーラスシリカ］触媒の混合触媒の製造
製造例４で製造したバリウムイオン交換ゼオライト１０ｇと製造例６の［Ｐｔ−Ｒｈ／メソポーラスシリカ］触媒１０ｇを均一に混合することによって、排ガス浄化用触媒を製造した。
「製造例１０」メソポーラス遷移金属窒化物と［Ｐｔ−Ｒｈ／メソポーラスシリカ］触媒の混合触媒の製造
製造例５で製造したメソポーラス遷移金属窒化物１０ｇと製造例６の［Ｐｔ−Ｒｈ／メソポーラスシリカ］触媒１０ｇを均一に混合することによって、排ガス浄化用触媒を製造した。
[Production Example 9] Production of mixed catalyst of zeolite and [Pt-Rh / mesoporous silica] catalyst 10 g of barium ion-exchanged zeolite produced in Production Example 4 and 10 g of [Pt-Rh / mesoporous silica] catalyst of Production Example 6 were evenly mixed. By mixing, an exhaust gas purification catalyst was produced.
[Production Example 10] Production of mixed catalyst of mesoporous transition metal nitride and [Pt-Rh / mesoporous silica] catalyst 10 g of mesoporous transition metal nitride produced in Production Example 5 and [Pt-Rh / mesoporous silica] of Production Example 6 An exhaust gas purifying catalyst was produced by uniformly mixing 10 g of the catalyst.
「製造例１１」モノリスに担持した［ゼオライト＋Ｐｔ−Ｒｈ／メソポーラスシリカ］触媒の合成
製造例４のバリウムイオン交換ゼオライト１ｇ、製造例６の［Ｐｔ−Ｒｈ／メソポーラスシリカ］触媒１ｇ、及びコロイダルシリカ０．１ｇを蒸留水１０ｍｌに加え、攪拌して、スラリーを調整した。これに、市販のコージェライトモノリス成形体（４００ｃｅｌｌｓ／ｉｎ２、直径１１８ｍｍ×長さ５０ｍｍ、重量２４３ｇ）から切り出したミニ成形体（２１ｃｅｌｌｓ、直径８ｍｍ×長さ９ｍｍ、重量０．１５ｇ）を５個浸漬し、試料をとりだし風乾した後、窒素気流下で５００℃−３時間熱処理した。混合触媒の付着量は、ミニ成形体の約１０質量％であり、ミニ成形体当たりの白金の担持量は約０．２質量％であった。
Production Example 11 Synthesis of [Zeolite + Pt—Rh / Mesoporous Silica] Catalyst Supported on Monolith 1 g of Barium Ion Exchanged Zeolite of Production Example 4, 1 g of [Pt—Rh / Mesoporous Silica] Catalyst of Production Example 6, and Colloidal Silica 0 0.1 g was added to 10 ml of distilled water and stirred to prepare a slurry. Five mini-molded bodies (21 cells, diameter 8 mm × length 9 mm, weight 0.15 g) cut from a commercially available cordierite monolith molded body (400 cells / in 2 , diameter 118 mm × length 50 mm, weight 243 g) After immersion, the sample was taken out and air-dried, and then heat-treated at 500 ° C. for 3 hours under a nitrogen stream. The adhesion amount of the mixed catalyst was about 10% by mass of the mini-molded body, and the supported amount of platinum per mini-molded body was about 0.2% by mass.
「実施例１、２、４、及び参考実施例３、５」、「比較例１」
還元剤としてプロピレンを用いたＮＯｘ処理
製造例１の三元触媒類似の触媒及び製造例７から１０の排ガス浄化用触媒をそれぞれ石英製の流通式反応管に０．３ｇ充填した。また、製造例１１のモノリス触媒である触媒担持のミニ成形体は石英製の連続流通式反応管に５個充填した。それぞれの反応管を外部ヒーターによって１５０℃〜５００℃までの任意の温度に調整した。次に、それぞれの反応管に、リーンバーンの模擬ガスとリッチバーンの模擬ガスを交互に１分間隔で流通し、ＮＯｘ処理を行った。リーンバーンの模擬ガスは、ヘリウムで濃度調整した一酸化窒素２５０ｐｐｍ、酸素１０％、水蒸気１０％，プロピレン４００ｐｐｍ含有ガスであり流量は毎分１００ｍＬとした。リッチバーンの模擬ガスは、ヘリウムで濃度調整した一酸化窒素２５０ｐｐｍ、酸素１％、水蒸気１０％，プロピレン４０００ｐｐｍ含有ガスであり流量は毎分１００ｍＬとした。排ガスをサンプリングし、ＮＯｘ浄化率と窒素の選択率を測定した。結果を表１に示した。
"Examples 1 , 2, 4 and Reference Examples 3 , 5 ", "Comparative Example 1"
NOx treatment using propylene as a reducing agent 0.3 g of a catalyst similar to the three-way catalyst of Production Example 1 and the exhaust gas purification catalyst of Production Examples 7 to 10 was charged in a quartz flow reaction tube. In addition, five catalyst-supported mini-molded bodies, which are monolith catalysts of Production Example 11, were filled in a quartz continuous flow reaction tube. Each reaction tube was adjusted to an arbitrary temperature of 150 ° C. to 500 ° C. by an external heater. Next, a simulated lean burn gas and a rich burn simulated gas were alternately passed through each reaction tube at 1-minute intervals to perform NOx treatment. The lean burn simulated gas was a gas containing 250 ppm of nitrogen monoxide, 10% of oxygen, 10% of water vapor, and 400 ppm of propylene adjusted in concentration with helium, and the flow rate was 100 mL per minute. The simulated gas of rich burn was a gas containing 250 ppm of nitrogen monoxide, 1% of oxygen, 10% of water vapor, and 4000 ppm of propylene adjusted in concentration with helium, and the flow rate was 100 mL per minute. The exhaust gas was sampled, and the NOx purification rate and nitrogen selectivity were measured. The results are shown in Table 1.
「実施例６」、「比較例２」
還元剤としてエタノールを用いたＮＯｘ処理
製造例１の三元触媒類似の触媒及び製造例７の排ガス浄化用触媒をそれぞれ石英製の連続流通式反応管に０．３ｇ充填した。それぞれの反応管を外部ヒーターによって１５０℃〜５００℃までの任意の温度に調整した。次に、それぞれの反応管に、リーンバーンの模擬ガスとリッチバーンの模擬ガスを交互に１分間隔で流通し、ＮＯｘ処理を行った。リーンバーンの模擬ガスは、ヘリウムで濃度調整した一酸化窒素２５０ｐｐｍ、酸素１０％、水蒸気１０％，エタノール４０００ｐｐｍ含有ガスであり流量は毎分１００ｍＬとした。リッチバーンの模擬ガスは、ヘリウムで濃度調整した一酸化窒素２５０ｐｐｍ、酸素１％、水蒸気１０％，エタノール１０００ｐｐｍ含有ガスであり流量は毎分１００ｍＬとした。排ガスをサンプリングし、ＮＯｘ浄化率と窒素の選択率を測定した。結果を表２に示した。
"Example 6", "Comparative example 2"
NOx treatment using ethanol as reducing agent 0.3 g of a catalyst similar to the three-way catalyst of Production Example 1 and the exhaust gas purification catalyst of Production Example 7 was charged in a quartz continuous flow reaction tube. Each reaction tube was adjusted to an arbitrary temperature of 150 ° C. to 500 ° C. by an external heater. Next, a simulated lean burn gas and a rich burn simulated gas were alternately passed through each reaction tube at 1-minute intervals to perform NOx treatment. The lean burn simulated gas was a gas containing 250 ppm of nitric oxide, 10% oxygen, 10% water vapor, and 4000 ppm ethanol adjusted in concentration with helium, and the flow rate was 100 mL per minute. The simulated gas for rich burn was a gas containing 250 ppm of nitric oxide, 1% of oxygen, 10% of water vapor, and 1000 ppm of ethanol adjusted in concentration with helium, and the flow rate was 100 mL per minute. The exhaust gas was sampled, and the NOx purification rate and nitrogen selectivity were measured. The results are shown in Table 2.
表１に示すように１８０℃から５００℃に渡って、６０％以上の高いＮＯｘ浄化率が得られた。また、窒素の選択率は、１８０〜２００℃で約１０％、２５０〜５００℃で約９０
％であった。
As shown in Table 1, a high NOx purification rate of 60% or more was obtained from 180 ° C. to 500 ° C. Further, the selectivity of nitrogen is about 10% at 180 to 200 ° C. and about 90 at 250 to 500 ° C.
%Met.
表２に示すように１８０℃から５００℃に渡って、８０％以上の高いＮＯｘ浄化率が得られた。また、窒素の選択率は、１８０℃〜５００℃で約９０％であった。
以上のことから、本発明の排ガス浄化方法は、リーンバーンとリッチバーンを交互に繰り返す内燃機関の排ガスを低温領域から高温領域に渡って効率よく浄化できることがわかる。
As shown in Table 2, a high NOx purification rate of 80% or more was obtained from 180 ° C. to 500 ° C. Moreover, the selectivity of nitrogen was about 90% at 180 ° C. to 500 ° C.
From the above, it can be seen that the exhaust gas purification method of the present invention can efficiently purify exhaust gas from an internal combustion engine that repeats lean burn and rich burn alternately from a low temperature region to a high temperature region.
本発明の排ガス浄化方法は、ディーゼル排ＮＯｘ浄化方法として有用である。 The exhaust gas purification method of the present invention is useful as a diesel exhaust NOx purification method.
Claims (1)
該ＮＯｘ吸着剤が、窒化炭素化合物、 炭窒化ホウ素化合物、及びチタンオキシナイトライド化合物から選ばれた少なくとも１種類の化合物であり、
又、 該ＮＯｘ酸化還元触媒がメソポーラス材料に白金主体の触媒を担持したメソポーラス白金触媒である
ことを特徴とする排ガス浄化方法。 In an exhaust gas purification method using an NOx adsorption redox catalyst comprising a NOx adsorbent and a NOx redox catalyst for exhaust gas purification of an internal combustion engine in which lean burn and rich burn are alternately repeated ,
The NOx adsorbent is at least one compound selected from a carbon nitride compound, a boron carbonitride compound, and a titanium oxynitride compound;
The exhaust gas purification method is characterized in that the NOx oxidation-reduction catalyst is a mesoporous platinum catalyst in which a platinum-based catalyst is supported on a mesoporous material .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007042564A JP4895858B2 (en) | 2007-02-22 | 2007-02-22 | New exhaust gas purification method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007042564A JP4895858B2 (en) | 2007-02-22 | 2007-02-22 | New exhaust gas purification method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2008200653A JP2008200653A (en) | 2008-09-04 |
| JP4895858B2 true JP4895858B2 (en) | 2012-03-14 |
Family
ID=39778677
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2007042564A Expired - Fee Related JP4895858B2 (en) | 2007-02-22 | 2007-02-22 | New exhaust gas purification method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4895858B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011052611A (en) * | 2009-09-02 | 2011-03-17 | Toyota Industries Corp | Device for controlling exhaust emission |
| WO2011049085A1 (en) * | 2009-10-20 | 2011-04-28 | 独立行政法人産業技術総合研究所 | Photocatalyst containing carbon nitride, method for producing same, and air purification method using the photocatalyst |
| CN108745404B (en) * | 2018-06-14 | 2020-12-04 | 苏州大学 | Carbon nitride film composite material based on black phosphorus/metal organic framework modification, preparation method thereof and application thereof in waste gas treatment |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3244370A1 (en) * | 1982-12-01 | 1984-06-07 | Basf Ag, 6700 Ludwigshafen | METHOD FOR THE REMOVAL OF DISTROXIDE OXIDE FROM HYDROGEN, NITROGEN MONOXIDE AND GASES CONTAINING DISTICKOXIDE |
| JP4063807B2 (en) * | 2004-09-14 | 2008-03-19 | 旭化成株式会社 | Exhaust gas purification catalyst |
| JP4712406B2 (en) * | 2005-02-08 | 2011-06-29 | 旭化成株式会社 | NOx purification catalyst |
| JP2006297348A (en) * | 2005-04-25 | 2006-11-02 | Asahi Kasei Corp | Catalyst for clarifying exhaust gas |
| JP2006305406A (en) * | 2005-04-26 | 2006-11-09 | Asahi Kasei Corp | CATALYST FOR REMOVING NOx IN EXHAUST GAS |
-
2007
- 2007-02-22 JP JP2007042564A patent/JP4895858B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2008200653A (en) | 2008-09-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7838461B2 (en) | Catalyst for exhaust gas purification | |
| EP1832345A1 (en) | Catalyst for exhaust gas purification | |
| JP6160005B2 (en) | CO selective methanation catalyst | |
| KR102320340B1 (en) | Low temperature DeNOx catalyst containing hierarchically structured porous TiO2 catalyst support and method for preparing the same | |
| JP4063807B2 (en) | Exhaust gas purification catalyst | |
| CN101733111B (en) | Perovskite/cerium dioxide composite catalyst and preparation method thereof and catalytic combustion on soot | |
| JP5116377B2 (en) | Exhaust NOx purification method | |
| JP2006305406A (en) | CATALYST FOR REMOVING NOx IN EXHAUST GAS | |
| JP2006297348A (en) | Catalyst for clarifying exhaust gas | |
| JP2008279352A (en) | Catalyst for removing nitrogen oxide discharged from lean burn automobile | |
| JP4749093B2 (en) | NOx purification catalyst carrier | |
| WO2011052676A1 (en) | Exhaust cleaner for internal combustion engine | |
| JP4895858B2 (en) | New exhaust gas purification method | |
| JP2008215253A (en) | NOx EMISSION CONTROL METHOD AND NOx EMISSION CONTROL DEVICE | |
| JP5112966B2 (en) | Lean burn exhaust gas purification catalyst | |
| JP5025148B2 (en) | Exhaust gas purification catalyst | |
| JP4233572B2 (en) | Honeycomb catalyst for exhaust gas purification | |
| JP4823100B2 (en) | New exhaust gas purification catalyst | |
| JP5036300B2 (en) | Automobile exhaust NOx purification catalyst and exhaust NOx purification method | |
| JP5758228B2 (en) | Supported catalysts containing rhodium and gold | |
| JP4712406B2 (en) | NOx purification catalyst | |
| JP4753613B2 (en) | NOx purification catalyst | |
| JP2011092852A (en) | Composite monolithic catalyst for cleaning exhaust gas | |
| JP5264316B2 (en) | Lean burn automobile exhaust gas purification catalyst | |
| JP2011177647A (en) | Compound monolithic catalyst for nox removal in lean burn automobile exhaust gas |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20100218 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20111013 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20111018 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20111129 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20111220 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20111220 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 4895858 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20150106 Year of fee payment: 3 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| LAPS | Cancellation because of no payment of annual fees |