CA1249571A - Catalyst composition for ultra high temperature operation - Google Patents
Catalyst composition for ultra high temperature operationInfo
- Publication number
- CA1249571A CA1249571A CA000484228A CA484228A CA1249571A CA 1249571 A CA1249571 A CA 1249571A CA 000484228 A CA000484228 A CA 000484228A CA 484228 A CA484228 A CA 484228A CA 1249571 A CA1249571 A CA 1249571A
- Authority
- CA
- Canada
- Prior art keywords
- base metal
- oxide
- alumina
- catalyst
- particles
- 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
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 84
- 239000000203 mixture Substances 0.000 title claims abstract description 63
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 94
- 239000010953 base metal Substances 0.000 claims abstract description 77
- 239000000843 powder Substances 0.000 claims abstract description 50
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 48
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 43
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 42
- 229910052751 metal Inorganic materials 0.000 claims abstract description 39
- 239000002184 metal Substances 0.000 claims abstract description 39
- 239000011246 composite particle Substances 0.000 claims abstract description 36
- 239000000758 substrate Substances 0.000 claims abstract description 28
- 239000002245 particle Substances 0.000 claims abstract description 25
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims abstract description 23
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims abstract description 20
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims abstract description 12
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 8
- 239000011651 chromium Substances 0.000 claims abstract description 8
- 229910052735 hafnium Inorganic materials 0.000 claims abstract description 8
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 8
- 239000010955 niobium Substances 0.000 claims abstract description 8
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims abstract description 8
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 7
- 239000010419 fine particle Substances 0.000 claims abstract description 7
- 238000002156 mixing Methods 0.000 claims abstract description 7
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical group [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 claims description 61
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Chemical compound [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 claims description 31
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 27
- 238000001354 calcination Methods 0.000 claims description 17
- 239000002131 composite material Substances 0.000 claims description 16
- 239000007787 solid Substances 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 13
- 238000010438 heat treatment Methods 0.000 claims description 7
- 229910001404 rare earth metal oxide Inorganic materials 0.000 claims description 7
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims description 5
- 229910000423 chromium oxide Inorganic materials 0.000 claims description 5
- 229910000449 hafnium oxide Inorganic materials 0.000 claims description 5
- WIHZLLGSGQNAGK-UHFFFAOYSA-N hafnium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Hf+4] WIHZLLGSGQNAGK-UHFFFAOYSA-N 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 5
- 229910000484 niobium oxide Inorganic materials 0.000 claims description 5
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 claims description 5
- 238000005755 formation reaction Methods 0.000 claims 3
- 238000004519 manufacturing process Methods 0.000 claims 2
- 206010037660 Pyrexia Diseases 0.000 claims 1
- 230000003213 activating effect Effects 0.000 claims 1
- 239000011819 refractory material Substances 0.000 claims 1
- 239000012798 spherical particle Substances 0.000 claims 1
- 239000011159 matrix material Substances 0.000 abstract description 2
- 239000000446 fuel Substances 0.000 description 27
- 239000000243 solution Substances 0.000 description 20
- 238000002485 combustion reaction Methods 0.000 description 19
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 18
- -1 platinum group metals Chemical class 0.000 description 16
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 10
- 239000010948 rhodium Substances 0.000 description 10
- 239000002253 acid Substances 0.000 description 9
- 238000000151 deposition Methods 0.000 description 9
- 150000002604 lanthanum compounds Chemical class 0.000 description 9
- 229910000510 noble metal Inorganic materials 0.000 description 9
- 238000002360 preparation method Methods 0.000 description 9
- 229930195733 hydrocarbon Natural products 0.000 description 8
- 150000002430 hydrocarbons Chemical class 0.000 description 8
- 229910052697 platinum Inorganic materials 0.000 description 8
- 229910052703 rhodium Inorganic materials 0.000 description 8
- 150000003839 salts Chemical group 0.000 description 8
- 230000003197 catalytic effect Effects 0.000 description 7
- 239000008367 deionised water Substances 0.000 description 7
- 229910021641 deionized water Inorganic materials 0.000 description 7
- 238000001035 drying Methods 0.000 description 7
- 239000011148 porous material Substances 0.000 description 7
- 241000907788 Cordia gerascanthus Species 0.000 description 6
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 6
- 230000008021 deposition Effects 0.000 description 6
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 229910002091 carbon monoxide Inorganic materials 0.000 description 5
- 150000001785 cerium compounds Chemical class 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- 238000005470 impregnation Methods 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 5
- 239000004215 Carbon black (E152) Substances 0.000 description 4
- 239000003929 acidic solution Substances 0.000 description 4
- 230000004913 activation Effects 0.000 description 4
- 150000001553 barium compounds Chemical class 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 238000002386 leaching Methods 0.000 description 4
- 229910052863 mullite Inorganic materials 0.000 description 4
- 239000002243 precursor Substances 0.000 description 4
- 238000005245 sintering Methods 0.000 description 4
- 230000002459 sustained effect Effects 0.000 description 4
- FQHYQCXMFZHLAE-UHFFFAOYSA-N 25405-85-0 Chemical compound CC1(C)C2(OC(=O)C=3C=CC=CC=3)C1C1C=C(CO)CC(C(C(C)=C3)=O)(O)C3C1(O)C(C)C2OC(=O)C1=CC=CC=C1 FQHYQCXMFZHLAE-UHFFFAOYSA-N 0.000 description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 229910002651 NO3 Inorganic materials 0.000 description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical compound [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 description 3
- 239000010779 crude oil Substances 0.000 description 3
- 238000007865 diluting Methods 0.000 description 3
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- KTUFCUMIWABKDW-UHFFFAOYSA-N oxo(oxolanthaniooxy)lanthanum Chemical compound O=[La]O[La]=O KTUFCUMIWABKDW-UHFFFAOYSA-N 0.000 description 3
- 229910052763 palladium Inorganic materials 0.000 description 3
- 229910052761 rare earth metal Inorganic materials 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 230000006641 stabilisation Effects 0.000 description 3
- 238000011105 stabilization Methods 0.000 description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 2
- 229910000505 Al2TiO5 Inorganic materials 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- 229910001111 Fine metal Inorganic materials 0.000 description 2
- 241000264877 Hippospongia communis Species 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 230000001464 adherent effect Effects 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000000498 ball milling Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000007084 catalytic combustion reaction Methods 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 229910052878 cordierite Inorganic materials 0.000 description 2
- YXVFQADLFFNVDS-UHFFFAOYSA-N diammonium citrate Chemical compound [NH4+].[NH4+].[O-]C(=O)CC(O)(C(=O)O)CC([O-])=O YXVFQADLFFNVDS-UHFFFAOYSA-N 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
- 230000000694 effects Effects 0.000 description 2
- 239000000839 emulsion Substances 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 2
- FYDKNKUEBJQCCN-UHFFFAOYSA-N lanthanum(3+);trinitrate Chemical compound [La+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O FYDKNKUEBJQCCN-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 150000002823 nitrates Chemical class 0.000 description 2
- 229910017464 nitrogen compound Inorganic materials 0.000 description 2
- 150000002830 nitrogen compounds Chemical class 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- AABBHSMFGKYLKE-SNAWJCMRSA-N propan-2-yl (e)-but-2-enoate Chemical compound C\C=C\C(=O)OC(C)C AABBHSMFGKYLKE-SNAWJCMRSA-N 0.000 description 2
- 150000002910 rare earth metals Chemical class 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- SONJTKJMTWTJCT-UHFFFAOYSA-K rhodium(iii) chloride Chemical compound [Cl-].[Cl-].[Cl-].[Rh+3] SONJTKJMTWTJCT-UHFFFAOYSA-K 0.000 description 2
- 238000012216 screening Methods 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 2
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- 229910000873 Beta-alumina solid electrolyte Inorganic materials 0.000 description 1
- 150000000703 Cerium Chemical class 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- DMCMMSCDJUQSIK-UHFFFAOYSA-N N.[Rh+3] Chemical compound N.[Rh+3] DMCMMSCDJUQSIK-UHFFFAOYSA-N 0.000 description 1
- 229910052779 Neodymium Inorganic materials 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
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910021604 Rhodium(III) chloride Inorganic materials 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- GMTXBUZKCHNBCH-UHFFFAOYSA-L [K].[Pt](Cl)Cl Chemical compound [K].[Pt](Cl)Cl GMTXBUZKCHNBCH-UHFFFAOYSA-L 0.000 description 1
- 150000001242 acetic acid derivatives Chemical class 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 229910000323 aluminium silicate Inorganic materials 0.000 description 1
- CNLWCVNCHLKFHK-UHFFFAOYSA-N aluminum;lithium;dioxido(oxo)silane Chemical compound [Li+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O CNLWCVNCHLKFHK-UHFFFAOYSA-N 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 1
- 150000008378 aryl ethers Chemical class 0.000 description 1
- FGEWSWBUAUZSTE-UHFFFAOYSA-L azane platinum(2+) dithiocyanate Chemical compound N.[Pt+2].[S-]C#N.[S-]C#N FGEWSWBUAUZSTE-UHFFFAOYSA-L 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 229910000420 cerium oxide Inorganic materials 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 239000003250 coal slurry Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 239000003085 diluting agent Substances 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012065 filter cake Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 150000002603 lanthanum Chemical class 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- 239000000391 magnesium silicate Substances 0.000 description 1
- 229910052919 magnesium silicate Inorganic materials 0.000 description 1
- 235000019792 magnesium silicate Nutrition 0.000 description 1
- 229910001510 metal chloride Inorganic materials 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 150000002826 nitrites Chemical class 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 150000002894 organic compounds Chemical class 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
- 230000001590 oxidative effect Effects 0.000 description 1
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 1
- SJLOMQIUPFZJAN-UHFFFAOYSA-N oxorhodium Chemical compound [Rh]=O SJLOMQIUPFZJAN-UHFFFAOYSA-N 0.000 description 1
- PIBWKRNGBLPSSY-UHFFFAOYSA-L palladium(II) chloride Chemical compound Cl[Pd]Cl PIBWKRNGBLPSSY-UHFFFAOYSA-L 0.000 description 1
- PUDIUYLPXJFUGB-UHFFFAOYSA-N praseodymium atom Chemical compound [Pr] PUDIUYLPXJFUGB-UHFFFAOYSA-N 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000003870 refractory metal Substances 0.000 description 1
- 229910003450 rhodium oxide Inorganic materials 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
- 230000035939 shock Effects 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 229910052642 spodumene Inorganic materials 0.000 description 1
- 150000004763 sulfides Chemical class 0.000 description 1
- 230000003685 thermal hair damage Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- DANYXEHCMQHDNX-UHFFFAOYSA-K trichloroiridium Chemical compound Cl[Ir](Cl)Cl DANYXEHCMQHDNX-UHFFFAOYSA-K 0.000 description 1
- 150000004684 trihydrates Chemical class 0.000 description 1
- 229910052845 zircon Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/56—Platinum group metals
- B01J23/64—Platinum group metals with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J23/648—Vanadium, niobium or tantalum or polonium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/56—Platinum group metals
- B01J23/63—Platinum group metals with rare earths or actinides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/56—Platinum group metals
- B01J23/64—Platinum group metals with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J23/652—Chromium, molybdenum or tungsten
- B01J23/6522—Chromium
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/04—Mixing
Abstract
Abstract of the Disclosure A high temperature stable catalyst is made with fine particles of a base metal such as chromium, hafnium and niobium or their oxides dispersed throughout a matrix made of composite particles having at least one platinum group metal on a ceria promoted, high temperature chemically stabilized refractory oxide powder. The refractory oxide powder can be either alumina, alumina powder which has been calcined at a temperature near incipient alpha alumina formation, silica-alumina or zirconia. The base metal or base metal oxide comprises about 15% to 90% by weight of the total weight and the platinum group metal comprises 0.05% to 10% by weight of the total weight. The catalyst composition can be applied as a washcoat to conventional substrates or it can be formed into shaped catalysts. The washcoat is made by mixing together one slip containing the composite particles with a second slip containing the base metal or base metal oxide particles.
Description
Background of the Invention 1. Field of the Invention This invention relates to a catalyst composition and methods for making the catalyst which is capable of sustained high temperature operation.
2. Description of the Previously Published Art Catalysts to carry out combustion of crude oil, hydrocarbon fuels, coal derived fuels, coal s]urries as well as hydrogen are being made with the ob~ectives of maximi~ing the heat output of the fuel as well as minimizing carbon monoxide, hydrocarbon and nitrogen oxide emissions. Reducing combustion temperatures to 1500C and below result in reduced nitrogen oxide emissions since the N2 + 2 -~ 2NO reaction is not favorable below that temperature. However, reducing the combustion temperatures by non-catalytic means still presents problems. If the amount of air is decreased to provide rich conditions, then there will be increased emissions of CO and hydrocarbons. If the amount of air is increased to provide lean conditions, then there will be increased NOX emissions as well as inefficient combustion as much of the heat generated during combustion is consumed in heating the diluent gases.
Catalytic combustion has the advantages of simultaneously reducing emission levels of all three components while efficiently combusting the fuel. It also has the advantage of permitting nearly complete combustion closer to the stoichiometric oxygen level. Because operation must be sustained at very high temperatures i.e., about 1200-1300C, for efficient operation, there is a need for ultra stable catalysts. Noble metals are effective catalytic components that have been used in first generation combustor systems. Many of the catalysts . ~
~ 5 ~ ~
are auto exhaust type catalysts which are not designed for very high temperature operation. The Ernest et al U.S.
Patent No. 4,170,573 discloses a catalyst composition comprising a composite of ceria, lanthana, and alumina with a catalytically-effective amount of one or more platinum group metals. At higher temperatures, however, noble metals exhibit increased vapor pressure in air and can result in significant losses of noble metals. For that reason a totally noble metal type system is not seen as a viable candidate for sustained ultra high temperature operation.
Base metal oxides (such as cr2O3) having low vapor pressure would be preferred. However, because of their dense, highly crystalline nature, they inherently do not bond well to ceramic substrates. Good bonding is a necessity due to the very high flow velocities encountered in combustor systems.
Catalytic combustion has the advantages of simultaneously reducing emission levels of all three components while efficiently combusting the fuel. It also has the advantage of permitting nearly complete combustion closer to the stoichiometric oxygen level. Because operation must be sustained at very high temperatures i.e., about 1200-1300C, for efficient operation, there is a need for ultra stable catalysts. Noble metals are effective catalytic components that have been used in first generation combustor systems. Many of the catalysts . ~
~ 5 ~ ~
are auto exhaust type catalysts which are not designed for very high temperature operation. The Ernest et al U.S.
Patent No. 4,170,573 discloses a catalyst composition comprising a composite of ceria, lanthana, and alumina with a catalytically-effective amount of one or more platinum group metals. At higher temperatures, however, noble metals exhibit increased vapor pressure in air and can result in significant losses of noble metals. For that reason a totally noble metal type system is not seen as a viable candidate for sustained ultra high temperature operation.
Base metal oxides (such as cr2O3) having low vapor pressure would be preferred. However, because of their dense, highly crystalline nature, they inherently do not bond well to ceramic substrates. Good bonding is a necessity due to the very high flow velocities encountered in combustor systems.
3. Objects of the Invention It is an object of this invention to produce a catalytic composition which is capable of sustained operation at very high temperature and which will efficiently combust fuel with minimum oxygen present.
It is a further object of this invention to produce a catalytic composition which when used in catalytic combustion will result in low emission levels.
It is a further object of this invention to produce a washcoat composition which can be applied to a substrate to form an efficient combustion catalyst that operates at high temperatures.
It is a further object of this invention to provide a method of forming a washcoat composition which after application to a substrate will firmly bond to the substrate and operate efficiently.
9S'~l These and further objects will become apparent as the description of the invention proceeds.
Summary of the ~nvention In this invention, these various prior art shortcomings have been overcome by forming a catalyst of a base metal or base metal oxide dispersed in a matrix of noble metal bearing bonding vehicle. The bonding vehicle consists of a refractory oxide such as zirconia, silica-alumina or alumina. A more preferred bonding vehicle is a stabilized alumina which has been stabilized with lanthana, a lanthana rich rare earth oxide or barium oxide. This bonding vehicle is itself catalyzed with noble metal, hence, providing not only bonding of the base metal oxide to the substrate, but also providing an active catalyst as well.
The invention provides a high temperature stable catalyst comprising a mixture of:
(a) fine particles of a base metal or base metal oxide selected from the group consisting of chromium, hafnium, niobium, chromium oxide, hafnium oxide, niobium oxide and mixtures thereof; and (b) composite particles of a ceria promoted, high temperature chemically stabilized refractory oxide powder having at least one platinum group metal thereon, said composite particles serving as a bonding vehicle for said base metal or base metal oxide particles whereby said base metal or base metal oxide particles are dispersed throughout the mixture and whereby said base metal or base metal oxide exists in a fine particulate form.
The catalyst material can be either applied as a washcoat to conventional catalyst substrates such as honeycomb monolith structures, particles or fibrous composites or the catalyst material may mixed into a paste 9 S 7 ~
and formed either into spheres or extruded into small individual particles or large, porous monolith bodies.
When making the catalyst to be applied as a washcoat, the washcoat is made by mixing together two slips. The first slip contains composite particles which have at least one platinum group metal on a ceria promoted, high temperature chemically stabilized refractory oxide powder. The second slip contains fine particles of a base metal or base metal oxide which is either chromium, hafnium or niobium or their oxides or mixtures thereof.
The resulting mixed slip is applied as a washcoat to a support and the coated support is heated to remove volatile materials. The preferred refractory oxide powders are alumina, alumina powder which has been
It is a further object of this invention to produce a catalytic composition which when used in catalytic combustion will result in low emission levels.
It is a further object of this invention to produce a washcoat composition which can be applied to a substrate to form an efficient combustion catalyst that operates at high temperatures.
It is a further object of this invention to provide a method of forming a washcoat composition which after application to a substrate will firmly bond to the substrate and operate efficiently.
9S'~l These and further objects will become apparent as the description of the invention proceeds.
Summary of the ~nvention In this invention, these various prior art shortcomings have been overcome by forming a catalyst of a base metal or base metal oxide dispersed in a matrix of noble metal bearing bonding vehicle. The bonding vehicle consists of a refractory oxide such as zirconia, silica-alumina or alumina. A more preferred bonding vehicle is a stabilized alumina which has been stabilized with lanthana, a lanthana rich rare earth oxide or barium oxide. This bonding vehicle is itself catalyzed with noble metal, hence, providing not only bonding of the base metal oxide to the substrate, but also providing an active catalyst as well.
The invention provides a high temperature stable catalyst comprising a mixture of:
(a) fine particles of a base metal or base metal oxide selected from the group consisting of chromium, hafnium, niobium, chromium oxide, hafnium oxide, niobium oxide and mixtures thereof; and (b) composite particles of a ceria promoted, high temperature chemically stabilized refractory oxide powder having at least one platinum group metal thereon, said composite particles serving as a bonding vehicle for said base metal or base metal oxide particles whereby said base metal or base metal oxide particles are dispersed throughout the mixture and whereby said base metal or base metal oxide exists in a fine particulate form.
The catalyst material can be either applied as a washcoat to conventional catalyst substrates such as honeycomb monolith structures, particles or fibrous composites or the catalyst material may mixed into a paste 9 S 7 ~
and formed either into spheres or extruded into small individual particles or large, porous monolith bodies.
When making the catalyst to be applied as a washcoat, the washcoat is made by mixing together two slips. The first slip contains composite particles which have at least one platinum group metal on a ceria promoted, high temperature chemically stabilized refractory oxide powder. The second slip contains fine particles of a base metal or base metal oxide which is either chromium, hafnium or niobium or their oxides or mixtures thereof.
The resulting mixed slip is applied as a washcoat to a support and the coated support is heated to remove volatile materials. The preferred refractory oxide powders are alumina, alumina powder which has been
- 4(a) -~2~95'7~
calcined at a temperature near incipient alpha alumina formation, silica-alumina or zirconia. The preferred high temperature stabilized refractory oxide is either lanthana stabilized alumina, a lanthana rich rare earth oxide stabilized alumina or a barium oxide stabilized alumina.
In the catalyst composition the base metal or metal oxide comprises 15% to 90% by weight of the total solids content of the washcoat. The platinum group metal comprises O.OS%
to 10% by weight of the total solids content of the washcoat. After the washcoat is applied, the catalyst may be further activated in a reducing atmosphere.
The catalyst composition of this invention has been found to be quite effective in catalyzing the combustion of crude oil and other hydrocarbon fuels which have been lS introduced to the catalytic combustor system as an atomized fuel-water emulsion. The crude oil or hydrocarbon fuel is catalytically combusted and the water is converted to superheated steam which is especially useful for down hole injection to remove heavy crudes.
Descri tion of the Preferred Embodiment p The catalysts made according to the present invention are suitable for use in high temperature combustor systems such as the type of boilerless steam generator described by J. A. Latty et al in European Patent 72,67S. In this system superheated steam is produced by burning a fuel in combination with the water. As seen in Figure 4 of the Latty et al patent the monolith catalysts are arranged vertically in series with the fuel and water applied to the top of the series.
By making catalysts according to the present invention from a washcoat formed from the two slip components, these high temperature stable catalysts can be effectively ~9~
employed in t~e combustor of a high temperature steam generator.
A preferred catalyst composition of the present invention comprises a mixture of ceria, lanthana, and a catalytlcally-effective amount of one or more platinum group metals deposited on the refractory oxide alumina to form a composite particle which is then in admixture with particles of a base metal or base metal oxide. The composite particle is prepared by depositing a cerium compound on a calcined admixture of the lanthana and the alumina and calcinirg the composite particle. Based upon the weight of the composite particle, the alumina, expressed as A12O3/ is present in an amount of from about 65 to about 98 weight percent; the lanthana, expressed as La2O3, is present in an amount of from about 1 to about 10 weight percent; and the ceria, expressed as CeO2, is present in an amount of from about 1 to about 25 weight percent. The base metal or base metal oxide particles are admixed with the composite particles in an approximate ratio of from about 1:5 to 10:1 on a weight basis which corresponds to about 15% to 90~ by weight of the total weight.
The catalyst is capable of operating in the combustion of carbonaceous fuel at high temperatures, e.g., greater than 2400F. (1317C), for extended periods of time such as 20 hours with low emissions of carbon monoxide and nitrogen oxides.
A method of preparing a catalyst according to this invention is illustrated using alumina as the refractory oxide powder by (1) forming an admixture of an aluminum compound and a lanthanum compound; (2) calcir.ing the admixture at a temperature of at least about 1800F
(983C); (3) depositing a cerium compound on the calcined admixture to form a composite (~) calcining the composite 9~'7~
at a temperature of at least about 1200F (649C); (5) depositing one or more platinum group metal compounds on the calcined composite; and (6) calcining the resulting composition at a temperature from about 500 to about 1400F (260-761C). The sequence of separate deposition and intermediate calcination employed with each metal compound in forming the composite provides effective stabilization of the alumina by the lanthana and of the platinum group metal by the ceria.
The base metal component is obtained commercially as fine metal powders. Alternatively, larger forms of the metal can be ground to produce the fine powder. The base metal oxide component is prepared by heating a salt form of the base metal such as chromic acetate to decompose it into the metal oxide form and then screening the powder to select the fine size. The powder is mixed with water to form a slip which is mixed with another slip made of the previously formed composite particles. The slips are mixed in appropriate ratios so that the ratio of the base metal (or metal oxide) to composite particles is from about 1:5 to 10:1 on a solids basis. The platinum group metal concentration is preferably about 4.5% of the total weight of the dried slip. To obtain this desired level, the amount of platinum group metal deposited on the composite particle will be varied depending on the ratio of the base metal particles to the composite particles used in forming the slip. For example, for a ratio of one part base metal or base metal oxide to three parts composite, then the preferred final 4.5~ platinum group metal content can be obtained by loading the composite particles with 6% platinum group metal. The resulting slip can be applied to a support and activated to form the final catalyst.
calcined at a temperature near incipient alpha alumina formation, silica-alumina or zirconia. The preferred high temperature stabilized refractory oxide is either lanthana stabilized alumina, a lanthana rich rare earth oxide stabilized alumina or a barium oxide stabilized alumina.
In the catalyst composition the base metal or metal oxide comprises 15% to 90% by weight of the total solids content of the washcoat. The platinum group metal comprises O.OS%
to 10% by weight of the total solids content of the washcoat. After the washcoat is applied, the catalyst may be further activated in a reducing atmosphere.
The catalyst composition of this invention has been found to be quite effective in catalyzing the combustion of crude oil and other hydrocarbon fuels which have been lS introduced to the catalytic combustor system as an atomized fuel-water emulsion. The crude oil or hydrocarbon fuel is catalytically combusted and the water is converted to superheated steam which is especially useful for down hole injection to remove heavy crudes.
Descri tion of the Preferred Embodiment p The catalysts made according to the present invention are suitable for use in high temperature combustor systems such as the type of boilerless steam generator described by J. A. Latty et al in European Patent 72,67S. In this system superheated steam is produced by burning a fuel in combination with the water. As seen in Figure 4 of the Latty et al patent the monolith catalysts are arranged vertically in series with the fuel and water applied to the top of the series.
By making catalysts according to the present invention from a washcoat formed from the two slip components, these high temperature stable catalysts can be effectively ~9~
employed in t~e combustor of a high temperature steam generator.
A preferred catalyst composition of the present invention comprises a mixture of ceria, lanthana, and a catalytlcally-effective amount of one or more platinum group metals deposited on the refractory oxide alumina to form a composite particle which is then in admixture with particles of a base metal or base metal oxide. The composite particle is prepared by depositing a cerium compound on a calcined admixture of the lanthana and the alumina and calcinirg the composite particle. Based upon the weight of the composite particle, the alumina, expressed as A12O3/ is present in an amount of from about 65 to about 98 weight percent; the lanthana, expressed as La2O3, is present in an amount of from about 1 to about 10 weight percent; and the ceria, expressed as CeO2, is present in an amount of from about 1 to about 25 weight percent. The base metal or base metal oxide particles are admixed with the composite particles in an approximate ratio of from about 1:5 to 10:1 on a weight basis which corresponds to about 15% to 90~ by weight of the total weight.
The catalyst is capable of operating in the combustion of carbonaceous fuel at high temperatures, e.g., greater than 2400F. (1317C), for extended periods of time such as 20 hours with low emissions of carbon monoxide and nitrogen oxides.
A method of preparing a catalyst according to this invention is illustrated using alumina as the refractory oxide powder by (1) forming an admixture of an aluminum compound and a lanthanum compound; (2) calcir.ing the admixture at a temperature of at least about 1800F
(983C); (3) depositing a cerium compound on the calcined admixture to form a composite (~) calcining the composite 9~'7~
at a temperature of at least about 1200F (649C); (5) depositing one or more platinum group metal compounds on the calcined composite; and (6) calcining the resulting composition at a temperature from about 500 to about 1400F (260-761C). The sequence of separate deposition and intermediate calcination employed with each metal compound in forming the composite provides effective stabilization of the alumina by the lanthana and of the platinum group metal by the ceria.
The base metal component is obtained commercially as fine metal powders. Alternatively, larger forms of the metal can be ground to produce the fine powder. The base metal oxide component is prepared by heating a salt form of the base metal such as chromic acetate to decompose it into the metal oxide form and then screening the powder to select the fine size. The powder is mixed with water to form a slip which is mixed with another slip made of the previously formed composite particles. The slips are mixed in appropriate ratios so that the ratio of the base metal (or metal oxide) to composite particles is from about 1:5 to 10:1 on a solids basis. The platinum group metal concentration is preferably about 4.5% of the total weight of the dried slip. To obtain this desired level, the amount of platinum group metal deposited on the composite particle will be varied depending on the ratio of the base metal particles to the composite particles used in forming the slip. For example, for a ratio of one part base metal or base metal oxide to three parts composite, then the preferred final 4.5~ platinum group metal content can be obtained by loading the composite particles with 6% platinum group metal. The resulting slip can be applied to a support and activated to form the final catalyst.
5'7~
When solutions of a lanthanum compound and a cerium compound are used to incorporate lanthana and ceria, then it is preferred to separately introduce each solution on the alumina to form a composite particle. The impregnation of each solution is followed by drying and calcination to deposit the metal oxide and the calcined composite particle is impregnated with a solution of one or more platinum group metal compounds.
Alumina forms the major portion of the preferred composite particles employed in the present invention.
Alumina or aluminum compounds, that are thermally decomposed to alumina by the calcination performed in preparing the admixture of either lanthana or baria and alumina, may be used as the starting material in the preparation o~ the composite particle. The lanthanum compound or the barium compound can be incorporated along with alumina which may be in the transitional alumina precursor form or in the activated or transitional alumina form. Activated or transitional aluminas include chi, rho, kappa, gamma, delta, eta, and theta aluminas.
Transitional aluminas are commercially available and are produced, Eor example, by heating alumina precursors such as aluminum halides, aluminum nitrate, alpha- or beta-alumina trihydrates, or alpha-alumina monohydrate.
Generally, transitional aluminas are formed by a calcination of the precursor at a temperature of at least about 750F (399C) for at least about 1 hour, preferably at a temperature from about 750 to about 1400F
(399-761C) for about 1 to about 4 hours. The activated alumina generally has a surface area of at least about 100 square meters per gram, preferably at least about 150 square meters per gram, and a total pore volume of at least about 0.4 cubic centimeters per gram, preferably from about 0.45 to about 1.5 cubic centimeters per gram.
~Z~9S'~
The surface areas referred to throughout the specification are those determined by the nitrogen BET method or equivalent methods. The pore volumes are determined by adding water to a powder sample to the point where incipient wetness just occurs.
Optionally, the activated alumina can be chemically treated to enhance the stability of the final catalyst composition. Such treatment can include leaching the alumina by contacting it with an acid such as nitric acid, acetic acid, or hydrochloric acid for a sufficient time to increase its surface area and to remove adsorbed impurities such as sodium ions which reduce high temperature stability. The length of time required for leaching will be influenced by numerous factors, including the pore volume of the alumina being leached, the concentration of acid in the leaching solution, the temperature at which leaching is carried out, and the extent to which improved stability and catalyst performance is desired. Generally, in order to avoid loss of alumina by conversion to water-soluble salts and to provide enhanced stability, the alumina may be contacted at ambient temperatures of about 65 to abou~ 80F
(18-27C) with an aqueous acidic solution having a pH of from about 3.0 to about 4.5 and maintained in contact with the solution for a period of at least about 2 hours, preferably from about 16 to about 72 hours. The alumina may be contacted with an amount of the aqueous acidic solution sufficient to provide between about 5 to about S0 parts by weight of acid per part by weight of alumina.
The leached alumina is then separated from the acidic solution and washed with the acidic solution and then water. Completion of the washing can be conveniently determined by measuring the pH of the wash water after it -~L~ ~ 9 5 ~
has contacted the leached alumina. Ordinarily the washing is complete when the wash water pH is above 4.5 or slightly higher. The alumina is then dried at about 200 to about 3509F (93-177C). The dried alumina generally s has a water pore volume of at least about 0.4 cubic centimeters per gram and a surface area of about 160 square meters per gram.
An admixture of alumina or other aluminum compound, and a lanthanum compound such as a lanthanum salt or a lanthanum rich rare earth compound (i.e. Ce-depleted rare earth mixture), or a barium compound is formed and calcined. For example, alumina may be impregnated with a solution of a thermally decomposable lanthanum compound and the impregnated alumina dried to remove the solvent and deposit the lanthanum compound on the alumina.
Compounds of other rare earth metals, such as praseodymium and neodymium, and the mixture with lanthanum compounds may be used to form admixtures of one or more rare earth metal oxides and alumina on calcination. However, such admixtures generally are more susceptible to the phase transformation to alpha-alumina than occurs at high temperatures than lanthana-alumina admixtures.
The usual thermally decomposable lanthanum compound or barium compound is a commercially available water soluble salt, of which the nitrate and acetate are preferred. The salt is dissolved to form an aqueous solution which is incorporated with the alumina either in the transitional alumina precursor form or in the activated or transitional form.
The solution contains sufficient amounts of the lanthanum or barium compound to provide the desired amount of lanthana or barium oxide in the admixture. The amount of lanthana or barium oxide employed for stabilization 9~
depends upon the degree of stability desired. As lanthana or barium oxide are very efficient inhibitors of the transition to alpha-alumina, excessive concentrations of lanthana or barium oxide of the order of 10 weight percent may not be cost effective. If an excessive proportion of alumina is present, it may not be stabilized sufficiently and will lose surface area in the transition to the alpha form Generally, the admixture of alumina and lanthana or baria comprises about 75-99 weight percent alumina, expressed as A12O3, and about 1-25 weight percent lanthana, expressed as La2O3 or baria (BaO). The preferred amount of stabilizing oxide is about 2 to about 10 weight percent to provide optimum stabilization against thermal damage and optimum catalyst performance.
The admixture may be dried at a temperature of from about 200 to about 400F (93-205C) for about 2 to about 20 hours. The admixture is then calcined at a temperature of at least about 1800F (983C), preferably from about 1800 to about 2400F (983-1317C) for about 1 to about 24 hours. Preferablyl the calcination is conducted in air or other oxidizing atmosphere. The temperature and time of the calcination are such as to provide an alumina/stabilizing oxide admixture having a relatively high surface area of at least about 25 square meters per gram, and preferably at least about 40 square meters per gram.
Calcination results in formation of the metal oxides, if the oxide forms are not used as the starting materials, and stabilizes the alumina. The admixture is calcined before any further steps in the method are performed.
In order to enhance the oxidation performance of the catalyst composition, ceria or another cerium compound is '7~
deposited on the calcined admixture of the lanthana or baria and the alumina prior to the deposition of the platinum group metal component and the resulting composite is calcined. The ceria enhances the dispersion and stability of the platinum group metal in the catalyst composition. It is preferred to incorporate the cerium component in intimate association with finely divided lanthana-alumina or baria-alumina by impregnatins the admixture with a solution of a cerium compound and calcining the resulting composite before it is coated on a substrate. An aqueous solution of cerium nitrate, chloride, acetate or any other suitable water-soluble salt that will decompose to the oxide on calcination may be employed. The stabilized-alumina may be impregnated to incipient wetness with a solution containing sufficient cerium salt to provide a ceria/lanthana or baria/alumina calcined composite that contains from about 1 to about 25 percent and preferably from about 3 to about 10 percent, by weight of cerium oxide expressed as CeO2.
The composite may be dried at a temperature of from about 200 to about 400C (93-205C) for about 2 to about 20 hours. The time and temperature of calcination are selected to avoid undue sintering and to provide a lanthana or baria/ceria/alumina composite having a surface area of at least about 25 square meters per gram.
Suitable conditions include a calcination in air at a temperature of at least about 1200F (649C), preferably from about 1800 to about 2400F (983-1317C) for about 1 to about 24 hours. The calcination before the deposition of the platinum group metal component prevents its occlusion by sintering.
The platinum group metal component may be platinum, palladium, rhodium, ruthenium, iridium, osmium, and - 12 ~
..
9~7~
mixtures thereof, with the preferred metals being Pt and Rh either alone or in any combination.
Various compounds, complexes, or fine metal dispersions of any of the platinum group metals in an aqueous or an organic medium may be used to achieve deposition of the platinum group metal component on the composite. A suitable liquid medium will not react with the platinum group metal component and is removable on drying which can be accomplished as part of the preparation or in use of the catalyst. Water soluble platinum group metal compounds or complexes may conveniently be used. Suitable platinum group metal compounds include chloroplatinic acid, potassium platinum chloride, ammonium platinum thiocyanate, platinum tetrammine hydroxide, platinum group metal chlorides, oxides, sulfides, nitrites and nitrates, platinum tetrammine chloride, palladium tetrammine chloridel sodium palladium chloride, hexammine rhodium chloride and hexammine iridium chloride.
In a preferred embodiment of this invention, the impregnation solution contains sulfito complexes of platinum group metals. For platinum either an acid or an ammonium sul~ito complex can be used. The most preferred platinum source is the ammonium sulfito complex prepared according to the methods described in U.S. Patent No~
3,932,309 (Graham et al). The use of these complexes provides excellent dispersion of the platinum group metal. Preferably, rhodium is incorporated in the catalyst by impregnation with either an acid or ammonium rhodium sulfito complex prepared by reacting rhodium trichloride or hydrous rhodium oxide with sulfurous acid or by impregnation with rhodium nitrate.
~L9~
In a preferred embodiment of this invention the composite particles are held preferably for at least about one hour at room temperature after each impregnation is completed with the metal or metals. The composition may then be dried, for example, at a temperature of from about 100C to about 150C for about 2 to about 20 hours. The salt composition may be decomposed and the catalyst activated under conditions which provide a composition having characteristics that promote the desired reaction.
The activation of the composite particles is done at a temperature which is at least high enough to decompose the platinum group metal bearing compounds. The compounds are decomposed to immobilize the metals before the composite particles are placed in the ball mill for mixing with the base metal particles. If the composite particles are air activated, then after the catalyst composition is finally produced the catalyst can be reduced. The temperature of this activation is low enough to permit neither noble metal sintering nor sintering of the support. The final activation of the formed catalyst is preferably done in a reducing atmosphere, e.g., by about a 1 hour reduction in flowing nitrogen containing 5 volume percent hydrogen at about 250-550C and more preferably at about 400C.
In the catalyst of this invention, the platinum group metals provide part of the catalytically active surfaces for oxidation, reduction and decomposition reactions and are present in amounts sufficient to provide catalytic compositions having significant activity for catalyzing these reactions. Generally, the amount of platinum group metal used is a minor portion of the catalyst composition and typically does not exceed about 10 weight peecent of the calcined washcoat composition. The amount may be about 0.05 to 10 percent and is preferably about 0.1 to 6 ~2'~5'7~
percent based on the weight of the calcined catalyst composition to maintain good activity with prolonged use.
The base metal component can be either commercially obtained fine powders or ground metal. The base metal oxide component is prepared by heating a salt form of the base metal such as chromic acetate to decompose it or by precipitating a hydrous form and then calcining it. The preferred base metals are chromium, hafnium and niobium.
They may be used in combination. The preferred salts are the chlorides, acetates and nitrates. The powder is then screened to select the fine size. The preferred powder size is less than about 10 microns. The powder is mixed with water to form a slip which is mixed with another slip made of the previously formed composite particles. The slips are mixed in appropriate ratios so that the ratio of the base metal (or metal oxide) to composite particles is from about 1:5 to 10:1 on a solids basis. The platinum group metal concentration is about 0.05 to about 10% and preferably about 4.5% of the total weight of the dried slip. To obtain this desired level, the amount of platinum group metal deposited on the composite particle will be varied depending on the ratio of the base metal particles to the composite particles used in forming the slip. The resulting slip is preferably ball milled to further reduce the particle size and to activate the surfaces to promote bonding. An acid may be added to peptize the solids. The ball milling can be done for any period of time up to 48 hours. The milled slip can be applied to a support and activated to form the final catalyst.
The catalyst composition of this invention is suitable for deposition on a substrate or for use without such deposition in either finely divided form or macrosize L95~7~
forms prepared by pelleting, extruding, and the like.
Preferably, the catalyst compositions are deposited on a rigid substrate capable of maintaining its shape and strength at high temperatures, for example up to about 3200F (1761C). The substrate typically is relatively catalytically inert and has a low thermal coefficient of expansion, good thermal shock resistance, and low thermal conductivity. Preferably, the structure has considerable excessible porosity, such as a water pore volume of at least about 5%. The substrate may be metallic or ceramic in nature or a combination thereof. Preferred substrate materials include refractory metal oxides such as alpha-alumina, aluminosilicates, zircon, magnesium silicate, cordierite, cordierite/alpha-alumina, si~icon nitrite, silicon carbide, zircon-mullite, spodumene, alumina-silica--magnesia, and zirconium silicate or refractory oxide composites such as mullite aluminum titanate. The preferred substrates for certain high temperature reactions are either monoliths or fibrous composites in the form of honeycombs and have a monolithic, skeletal structure having gas flow channels extending therethrough.
In preparing substrates coated with the catalyst compositions of this invention, an aqueous slurry or slip of the essentially water insoluble catalyst composition made of the composite particles and the base metal oxide particles is contacted with the substrate as by dipping the substrate into the slip. After drying, the solid content of the slurry forms an adherent deposit on the substrate. For example, using any suitable grinding means, such as acid ball milling, the composition is reduced to a particle size of about 1 to about 10 microns and homogenized with acid to form the slip. The coated '7~
substrate is then dried at a temperature of from about 200 to about 400F (95-205C) for about 1 to about 4 hours to remove, the solvent and deposit the solids in an adherent film on the substrate. The dried monolith may be calcined at from about 500 to about 1400F (~60-761C) for about 1 to about 4 hours. The base metal or base metal oxide exists in a discrete particulate form and not as a monolayer coating or monolayer deposit on the surface of the refractory oxide particles.
The amount of the composition that is coated on the substrate depends on economics, size limitations, an design characteristics. Generally, the composition comprises about 1 to about 20 weight percent based upon the weight of the substrate.
Monolithic catalytic compositions prepared in accordance with this invention are particularly useful when employed in the high temperature combustion of carbonaceous fuels. Flammable mixtures of most fuels are normally constituted to burn with relatively high flame temperatures, i.e., about 3300F (1817C) and above, at which substantial amounts of nitrogen oxides are formed.
However, there is little or no formation of nitrogen oxides from nitrogen in the air in a system which burns the fuel catalytically at lower temperatures. There may be some nitrogen oxides formed when the nitrogen compounds in the fuel are oxidized.
The catalyst composition of this invention may be used for the combustion of carbonaceous fuel by contacting a fuel/air admixture with the composition on the monolithic substrate at a temperature sufficient to combust the admixture. The proportions of fuel and air in the admixture charged to the combustion zone are typically such that there is a stoichiometric excess of oxygen based on the complete conversion of the fuel to carbon dioxide and water.
~ 2 ~
Suitable g~seous or liquid fuels include, for example, low molecular weight aliphatic hydrocarbons, aromatic hydrocarbons, middle distillate fuels, hydrotreated heavier fuels, alcohols, ethers, aromatic ethers, coal slurries, carbon monoxide, and hydrogen.
The fuel-air mixture is generally passed to the catalyst in the combustion zone at a linear gas velocity of above about 3 feet per second, but considerably higher velocities may be required depending upon such factors as temperature, pressure and fuel composition, The catalyst composition generally operates at temperatures from about 1700 to about 3200F
(927-1761C) preferably about 2000 to about 3000F
(1094-1650C). The temperature of the catalyst zone may be controlled by controlling the fuel-air ratio. The total residence time in the combustion system should be sufficient to provide essentially complete combustion of the fuel.
The catalyst of this invention can also be used to promote the oxidation of hydrocarbons, oxygen-containing organic compounds such as aldehydes and organic acids, carbon monoxide and other products of incomplete combustion. The catalysts of the present invention are especially useful in the conversion of carbon monoxide and partially combusted hydrocarbons that are present in the exhaust gases from the combustion of carbonaceous fuels.
Under reducing conditions, which are deficient in oxygen, the catalyst can reduce NOX levels where rhodium is pre~ent or palladium is present~
Having described the basic aspects of our inventionr the following examples are given to illustrate specific embodiments thereof.
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Example 1 This example illustrates the preparation of an active lanthana alumina powder.
A lanthanum nitrate solution was prepared by dissolving 5433 grams of lanthanum nitrate crystals (37.6%
La2O3) in 56.77 liters of water and adding ln2.96 kilograms of an alumina filter cake having a solids content of 31% made by the procedure described in U.S.
Patent No. 4,371,513 to Sanchez et al. The resulting slurry was then spray dried using a vane wheel revolving at 18,000 rpm with an inlet temperature of 800F (427C) and an outlet temperature of 300F (149C). The spray dried powder has a TV of 8.24~ and a total rare earth oxide content of 6.06%.
This resulting lanthana containing powder was calcined for one hour at 2300F (1260C) to produce a powder having a water pore volume of 0.905 cc/g, a BET (N2) surface area of 44 m /g, and an alpha-alumina content of 4.5~.
Example 2 This example illustrates the preparation of a ceria activated lanthana alumina powder.
The lanthana alumina powder of Example 1 in an amount of 2825 grams was impregnated to full incipient wetness (2555 ml.) with a solution prepared by diluting 355.2 grams of a cerous nitrate solution (24.6% CeO2) with deionized water. The nominal CeO2 level was 3~. This was dried at 275F (135C) and subsequently activated for one hour at 2200F (1204C). The resulting activated powder had a water pore volume of 0.95 cc/g, a TV of 0.34~, an alpha-alumina content of 4.9% and a RET (N2) surface area of 37 m /g.
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Example 3 This example illustrates the preparation of washcoat powder containing 6% platinum/rhodium (weight ratio of 19/1) to be identified as Powder A.
The lanthana-ceria alumina powder of Example 2 in an amount of 600 grams (dry basis) was impregnated to full incipient wetness (572 ml.) with a solution prepared by mixing 379.07 grams of (NH4)6 Pt(SO3)~ solution (9.598~ Pt), 43.77 grams of Rh(NO3)3 solution (4.375%
Rh), 6 grams of dibasic ammonium citrate and then diluting with deionized water. The impregnated powder was allowed to stand in a sealed polyethylene bag for one hour prior to drying at 275F (135C). The dried powder was activated in air at 1000F (538C) for one hour and it will be referred to hereafter as Powder A.
Example 4 This example illustrates the preparation of a washcoat powder containing 4% platinum/rhodium (weight ratio of 19/1) to be identified as Powder B .
The lanthana-ceria alumina powder of Example 2 in an amount of 200 grams was impregnated to full incipient wetness (191 ml.) with a solution prepared by mixing 82.48 grams of (NH4)6 Pt(SO3)4 solution (9.598~ Pt), 9.524 grams of Rh(NO3)3 solution (4.375% Rh), 2 grams of dibasic ammonium citrate and then diluting with deionized water. The impreganted powder was allowed to stand in a sealed polyethylene bag for one hour prior to drying at 275F (135C). The dried powder was activated in air at 1000F (538C) for one hour and it will be referred to hereafter as Powder B.
Example 5 This example illustrates the preparation o~ the Cr2O3 component of the catalyst composition of this invention to be identified as Powder C.
, - 20 -~ 9 S~
Chromic acetate in an amount of 1000 grams was decomposed by heating to 1200F (649C) in air and then screening to a particle siæe of less than or equal to 250 microns followed by activation at 2000F (1093C) for one hour. This Cr2O3 powder has a BET (N2) surface area of 5 m /g and will be referred to hereafter as Powder C.
Example 6 This example illustrates the preparation of a monolithic combustion catalyst utilizing washcoat Powders A and C.
Powder A as prepared in Example 3 in an amount of 120 grams was ball milled with 255 grams of deionized water for 18 hours. The resulting slip had a pH of 4.54. A
second slip was made with 32 grams of Powder C as prepared in Example 5 which was ball milled with 106 grams of deionized water for 18 hours. The resulting slip had a pH
of 6.5. The two slips were mixed in a 3 to 1 ratio (on a solids basis) such that the resulting noble metal concentration of the dried slip when applied to a monolith would be 4.5~. The mixed slip had a pH of 4.59 and a viscosity of 700 centipoise at a solids content of 3.18%.
Mullite aluminum titanate (MAT) monoliths of 3.17"
diameter and 1/2~ thickness (obtained from Corning Glass) having nominally 16 cells per square inch were double coated with drying at 350F (177C) between coats. The coated units were finally activated in a flow of 5~
hydrogen balance nitrogen at 725-750F (385-399C) for 2 hours. The washcoat thickness was calculated to be 53 microns.
Example 7 This example illustrates the preparation of a monolithic combustion catalyst utilizing washcoat Powders B and C.
~z~3S~7~
Powder B as prepared in Example 4 in an amount of 75 grams was ball milled with 159 grams of deionized water for 18 hours. A second slip was made with 30 grams of Powder C as prepared in Example 5 which was ball milled with 64 grams of deionized water for 18 hours. The resulting second slip had a pH of 6. 57 ~ The two slips were mixed in a 3 to 1 ratio (on a solids basis) such that the resulting noble metal concentration of the dried slip when applied to a monolith would be 3~ The mixed slip had a pH of 4~45 at a solids content of 30~6~o Mullite alumina titanate (MAT) monoliths of 3~17~ diameter and 1/2~ thickness (obtained from Corning Glass) having nominally 64 cells per square inch were double coated with drying at 350F (177C) between coats. The coated units were finally activated in a flow of 5% hydrogen balance nitrogen at 725-750F (385-399C) for 2 hours. The washcoat thickness was calculated to be 49 microns.
Example 8 A test unit was employed having 10 monolith catalyst sections each having a diameter of 8 ~ 05 cm and a thickness of 1~27 cm. The first four monolith sections had 16 cells per square inch and the remaining 6 sections downstream had 64 cells per square inch. The monolith sections were arranged in pairs with reaction space provided between each pair. The 16 cell monolith catalysts were prepared according to Example 6 and the 64 cell monolith catalyst was prepared according to Example 7. The first four and last two monolith sections had been previously run in the device for about 8-1/2 hours. The fifth through eighth units had been used for about 23-1/2 hours.
During the period of the test the air fuel ratio was varied around the stoichiometric point and especially into the slightly lean region. After the system reached a ~ 22 ~
~ Z~ 5~7~
steady-state temperature the temperature in the reaction zone following the first four monoliths was about 2400F
(1316C) and in the reaction zone before the last two monoliths it was about 2050F (1121C). Thus the catalysts were experiencing temperatures of at least 2000F (1093C) throughout the test. The air flow rate was approximately 150 SCFM, the fuel emulsion was supplied at 0.36-0.38 gallon/minute and the system pressure was approximately 500 psi. The results are set forth in Table 1.
Table 1 Time CO 2 UHC Nx Equivalence Hr:min ~ ppm p~ Ratio 1:23 60 0.1 6 90 1.057 2:45 0 2 0.5 118 0.99 1 UHC is unburned hydrocarbons 2 Equivalence ratio relates to the amount of air used compared to the theoretical, stoichiometric amount which is 1Ø For values greater than 1.0, the mixture is rich and for values less than 1.0, the mixture is lean. The target is to operate at 1Ø
The results show that after 2 hours and ~5 minutes on stream the catalysts were still effective since the final CO was a low 0 ppm, the UHC was only 0.5 ppm and the NOX
was 118 ppm. This amount of NOX cannot be totally eliminated since there is always some nitrogen present as nitrogen compounds in the fuel.
The catalysts used in this system are also advantageous since they are capable of being lit off after repeated usage.
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It is understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of this invention.
. . - 24 -
When solutions of a lanthanum compound and a cerium compound are used to incorporate lanthana and ceria, then it is preferred to separately introduce each solution on the alumina to form a composite particle. The impregnation of each solution is followed by drying and calcination to deposit the metal oxide and the calcined composite particle is impregnated with a solution of one or more platinum group metal compounds.
Alumina forms the major portion of the preferred composite particles employed in the present invention.
Alumina or aluminum compounds, that are thermally decomposed to alumina by the calcination performed in preparing the admixture of either lanthana or baria and alumina, may be used as the starting material in the preparation o~ the composite particle. The lanthanum compound or the barium compound can be incorporated along with alumina which may be in the transitional alumina precursor form or in the activated or transitional alumina form. Activated or transitional aluminas include chi, rho, kappa, gamma, delta, eta, and theta aluminas.
Transitional aluminas are commercially available and are produced, Eor example, by heating alumina precursors such as aluminum halides, aluminum nitrate, alpha- or beta-alumina trihydrates, or alpha-alumina monohydrate.
Generally, transitional aluminas are formed by a calcination of the precursor at a temperature of at least about 750F (399C) for at least about 1 hour, preferably at a temperature from about 750 to about 1400F
(399-761C) for about 1 to about 4 hours. The activated alumina generally has a surface area of at least about 100 square meters per gram, preferably at least about 150 square meters per gram, and a total pore volume of at least about 0.4 cubic centimeters per gram, preferably from about 0.45 to about 1.5 cubic centimeters per gram.
~Z~9S'~
The surface areas referred to throughout the specification are those determined by the nitrogen BET method or equivalent methods. The pore volumes are determined by adding water to a powder sample to the point where incipient wetness just occurs.
Optionally, the activated alumina can be chemically treated to enhance the stability of the final catalyst composition. Such treatment can include leaching the alumina by contacting it with an acid such as nitric acid, acetic acid, or hydrochloric acid for a sufficient time to increase its surface area and to remove adsorbed impurities such as sodium ions which reduce high temperature stability. The length of time required for leaching will be influenced by numerous factors, including the pore volume of the alumina being leached, the concentration of acid in the leaching solution, the temperature at which leaching is carried out, and the extent to which improved stability and catalyst performance is desired. Generally, in order to avoid loss of alumina by conversion to water-soluble salts and to provide enhanced stability, the alumina may be contacted at ambient temperatures of about 65 to abou~ 80F
(18-27C) with an aqueous acidic solution having a pH of from about 3.0 to about 4.5 and maintained in contact with the solution for a period of at least about 2 hours, preferably from about 16 to about 72 hours. The alumina may be contacted with an amount of the aqueous acidic solution sufficient to provide between about 5 to about S0 parts by weight of acid per part by weight of alumina.
The leached alumina is then separated from the acidic solution and washed with the acidic solution and then water. Completion of the washing can be conveniently determined by measuring the pH of the wash water after it -~L~ ~ 9 5 ~
has contacted the leached alumina. Ordinarily the washing is complete when the wash water pH is above 4.5 or slightly higher. The alumina is then dried at about 200 to about 3509F (93-177C). The dried alumina generally s has a water pore volume of at least about 0.4 cubic centimeters per gram and a surface area of about 160 square meters per gram.
An admixture of alumina or other aluminum compound, and a lanthanum compound such as a lanthanum salt or a lanthanum rich rare earth compound (i.e. Ce-depleted rare earth mixture), or a barium compound is formed and calcined. For example, alumina may be impregnated with a solution of a thermally decomposable lanthanum compound and the impregnated alumina dried to remove the solvent and deposit the lanthanum compound on the alumina.
Compounds of other rare earth metals, such as praseodymium and neodymium, and the mixture with lanthanum compounds may be used to form admixtures of one or more rare earth metal oxides and alumina on calcination. However, such admixtures generally are more susceptible to the phase transformation to alpha-alumina than occurs at high temperatures than lanthana-alumina admixtures.
The usual thermally decomposable lanthanum compound or barium compound is a commercially available water soluble salt, of which the nitrate and acetate are preferred. The salt is dissolved to form an aqueous solution which is incorporated with the alumina either in the transitional alumina precursor form or in the activated or transitional form.
The solution contains sufficient amounts of the lanthanum or barium compound to provide the desired amount of lanthana or barium oxide in the admixture. The amount of lanthana or barium oxide employed for stabilization 9~
depends upon the degree of stability desired. As lanthana or barium oxide are very efficient inhibitors of the transition to alpha-alumina, excessive concentrations of lanthana or barium oxide of the order of 10 weight percent may not be cost effective. If an excessive proportion of alumina is present, it may not be stabilized sufficiently and will lose surface area in the transition to the alpha form Generally, the admixture of alumina and lanthana or baria comprises about 75-99 weight percent alumina, expressed as A12O3, and about 1-25 weight percent lanthana, expressed as La2O3 or baria (BaO). The preferred amount of stabilizing oxide is about 2 to about 10 weight percent to provide optimum stabilization against thermal damage and optimum catalyst performance.
The admixture may be dried at a temperature of from about 200 to about 400F (93-205C) for about 2 to about 20 hours. The admixture is then calcined at a temperature of at least about 1800F (983C), preferably from about 1800 to about 2400F (983-1317C) for about 1 to about 24 hours. Preferablyl the calcination is conducted in air or other oxidizing atmosphere. The temperature and time of the calcination are such as to provide an alumina/stabilizing oxide admixture having a relatively high surface area of at least about 25 square meters per gram, and preferably at least about 40 square meters per gram.
Calcination results in formation of the metal oxides, if the oxide forms are not used as the starting materials, and stabilizes the alumina. The admixture is calcined before any further steps in the method are performed.
In order to enhance the oxidation performance of the catalyst composition, ceria or another cerium compound is '7~
deposited on the calcined admixture of the lanthana or baria and the alumina prior to the deposition of the platinum group metal component and the resulting composite is calcined. The ceria enhances the dispersion and stability of the platinum group metal in the catalyst composition. It is preferred to incorporate the cerium component in intimate association with finely divided lanthana-alumina or baria-alumina by impregnatins the admixture with a solution of a cerium compound and calcining the resulting composite before it is coated on a substrate. An aqueous solution of cerium nitrate, chloride, acetate or any other suitable water-soluble salt that will decompose to the oxide on calcination may be employed. The stabilized-alumina may be impregnated to incipient wetness with a solution containing sufficient cerium salt to provide a ceria/lanthana or baria/alumina calcined composite that contains from about 1 to about 25 percent and preferably from about 3 to about 10 percent, by weight of cerium oxide expressed as CeO2.
The composite may be dried at a temperature of from about 200 to about 400C (93-205C) for about 2 to about 20 hours. The time and temperature of calcination are selected to avoid undue sintering and to provide a lanthana or baria/ceria/alumina composite having a surface area of at least about 25 square meters per gram.
Suitable conditions include a calcination in air at a temperature of at least about 1200F (649C), preferably from about 1800 to about 2400F (983-1317C) for about 1 to about 24 hours. The calcination before the deposition of the platinum group metal component prevents its occlusion by sintering.
The platinum group metal component may be platinum, palladium, rhodium, ruthenium, iridium, osmium, and - 12 ~
..
9~7~
mixtures thereof, with the preferred metals being Pt and Rh either alone or in any combination.
Various compounds, complexes, or fine metal dispersions of any of the platinum group metals in an aqueous or an organic medium may be used to achieve deposition of the platinum group metal component on the composite. A suitable liquid medium will not react with the platinum group metal component and is removable on drying which can be accomplished as part of the preparation or in use of the catalyst. Water soluble platinum group metal compounds or complexes may conveniently be used. Suitable platinum group metal compounds include chloroplatinic acid, potassium platinum chloride, ammonium platinum thiocyanate, platinum tetrammine hydroxide, platinum group metal chlorides, oxides, sulfides, nitrites and nitrates, platinum tetrammine chloride, palladium tetrammine chloridel sodium palladium chloride, hexammine rhodium chloride and hexammine iridium chloride.
In a preferred embodiment of this invention, the impregnation solution contains sulfito complexes of platinum group metals. For platinum either an acid or an ammonium sul~ito complex can be used. The most preferred platinum source is the ammonium sulfito complex prepared according to the methods described in U.S. Patent No~
3,932,309 (Graham et al). The use of these complexes provides excellent dispersion of the platinum group metal. Preferably, rhodium is incorporated in the catalyst by impregnation with either an acid or ammonium rhodium sulfito complex prepared by reacting rhodium trichloride or hydrous rhodium oxide with sulfurous acid or by impregnation with rhodium nitrate.
~L9~
In a preferred embodiment of this invention the composite particles are held preferably for at least about one hour at room temperature after each impregnation is completed with the metal or metals. The composition may then be dried, for example, at a temperature of from about 100C to about 150C for about 2 to about 20 hours. The salt composition may be decomposed and the catalyst activated under conditions which provide a composition having characteristics that promote the desired reaction.
The activation of the composite particles is done at a temperature which is at least high enough to decompose the platinum group metal bearing compounds. The compounds are decomposed to immobilize the metals before the composite particles are placed in the ball mill for mixing with the base metal particles. If the composite particles are air activated, then after the catalyst composition is finally produced the catalyst can be reduced. The temperature of this activation is low enough to permit neither noble metal sintering nor sintering of the support. The final activation of the formed catalyst is preferably done in a reducing atmosphere, e.g., by about a 1 hour reduction in flowing nitrogen containing 5 volume percent hydrogen at about 250-550C and more preferably at about 400C.
In the catalyst of this invention, the platinum group metals provide part of the catalytically active surfaces for oxidation, reduction and decomposition reactions and are present in amounts sufficient to provide catalytic compositions having significant activity for catalyzing these reactions. Generally, the amount of platinum group metal used is a minor portion of the catalyst composition and typically does not exceed about 10 weight peecent of the calcined washcoat composition. The amount may be about 0.05 to 10 percent and is preferably about 0.1 to 6 ~2'~5'7~
percent based on the weight of the calcined catalyst composition to maintain good activity with prolonged use.
The base metal component can be either commercially obtained fine powders or ground metal. The base metal oxide component is prepared by heating a salt form of the base metal such as chromic acetate to decompose it or by precipitating a hydrous form and then calcining it. The preferred base metals are chromium, hafnium and niobium.
They may be used in combination. The preferred salts are the chlorides, acetates and nitrates. The powder is then screened to select the fine size. The preferred powder size is less than about 10 microns. The powder is mixed with water to form a slip which is mixed with another slip made of the previously formed composite particles. The slips are mixed in appropriate ratios so that the ratio of the base metal (or metal oxide) to composite particles is from about 1:5 to 10:1 on a solids basis. The platinum group metal concentration is about 0.05 to about 10% and preferably about 4.5% of the total weight of the dried slip. To obtain this desired level, the amount of platinum group metal deposited on the composite particle will be varied depending on the ratio of the base metal particles to the composite particles used in forming the slip. The resulting slip is preferably ball milled to further reduce the particle size and to activate the surfaces to promote bonding. An acid may be added to peptize the solids. The ball milling can be done for any period of time up to 48 hours. The milled slip can be applied to a support and activated to form the final catalyst.
The catalyst composition of this invention is suitable for deposition on a substrate or for use without such deposition in either finely divided form or macrosize L95~7~
forms prepared by pelleting, extruding, and the like.
Preferably, the catalyst compositions are deposited on a rigid substrate capable of maintaining its shape and strength at high temperatures, for example up to about 3200F (1761C). The substrate typically is relatively catalytically inert and has a low thermal coefficient of expansion, good thermal shock resistance, and low thermal conductivity. Preferably, the structure has considerable excessible porosity, such as a water pore volume of at least about 5%. The substrate may be metallic or ceramic in nature or a combination thereof. Preferred substrate materials include refractory metal oxides such as alpha-alumina, aluminosilicates, zircon, magnesium silicate, cordierite, cordierite/alpha-alumina, si~icon nitrite, silicon carbide, zircon-mullite, spodumene, alumina-silica--magnesia, and zirconium silicate or refractory oxide composites such as mullite aluminum titanate. The preferred substrates for certain high temperature reactions are either monoliths or fibrous composites in the form of honeycombs and have a monolithic, skeletal structure having gas flow channels extending therethrough.
In preparing substrates coated with the catalyst compositions of this invention, an aqueous slurry or slip of the essentially water insoluble catalyst composition made of the composite particles and the base metal oxide particles is contacted with the substrate as by dipping the substrate into the slip. After drying, the solid content of the slurry forms an adherent deposit on the substrate. For example, using any suitable grinding means, such as acid ball milling, the composition is reduced to a particle size of about 1 to about 10 microns and homogenized with acid to form the slip. The coated '7~
substrate is then dried at a temperature of from about 200 to about 400F (95-205C) for about 1 to about 4 hours to remove, the solvent and deposit the solids in an adherent film on the substrate. The dried monolith may be calcined at from about 500 to about 1400F (~60-761C) for about 1 to about 4 hours. The base metal or base metal oxide exists in a discrete particulate form and not as a monolayer coating or monolayer deposit on the surface of the refractory oxide particles.
The amount of the composition that is coated on the substrate depends on economics, size limitations, an design characteristics. Generally, the composition comprises about 1 to about 20 weight percent based upon the weight of the substrate.
Monolithic catalytic compositions prepared in accordance with this invention are particularly useful when employed in the high temperature combustion of carbonaceous fuels. Flammable mixtures of most fuels are normally constituted to burn with relatively high flame temperatures, i.e., about 3300F (1817C) and above, at which substantial amounts of nitrogen oxides are formed.
However, there is little or no formation of nitrogen oxides from nitrogen in the air in a system which burns the fuel catalytically at lower temperatures. There may be some nitrogen oxides formed when the nitrogen compounds in the fuel are oxidized.
The catalyst composition of this invention may be used for the combustion of carbonaceous fuel by contacting a fuel/air admixture with the composition on the monolithic substrate at a temperature sufficient to combust the admixture. The proportions of fuel and air in the admixture charged to the combustion zone are typically such that there is a stoichiometric excess of oxygen based on the complete conversion of the fuel to carbon dioxide and water.
~ 2 ~
Suitable g~seous or liquid fuels include, for example, low molecular weight aliphatic hydrocarbons, aromatic hydrocarbons, middle distillate fuels, hydrotreated heavier fuels, alcohols, ethers, aromatic ethers, coal slurries, carbon monoxide, and hydrogen.
The fuel-air mixture is generally passed to the catalyst in the combustion zone at a linear gas velocity of above about 3 feet per second, but considerably higher velocities may be required depending upon such factors as temperature, pressure and fuel composition, The catalyst composition generally operates at temperatures from about 1700 to about 3200F
(927-1761C) preferably about 2000 to about 3000F
(1094-1650C). The temperature of the catalyst zone may be controlled by controlling the fuel-air ratio. The total residence time in the combustion system should be sufficient to provide essentially complete combustion of the fuel.
The catalyst of this invention can also be used to promote the oxidation of hydrocarbons, oxygen-containing organic compounds such as aldehydes and organic acids, carbon monoxide and other products of incomplete combustion. The catalysts of the present invention are especially useful in the conversion of carbon monoxide and partially combusted hydrocarbons that are present in the exhaust gases from the combustion of carbonaceous fuels.
Under reducing conditions, which are deficient in oxygen, the catalyst can reduce NOX levels where rhodium is pre~ent or palladium is present~
Having described the basic aspects of our inventionr the following examples are given to illustrate specific embodiments thereof.
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Example 1 This example illustrates the preparation of an active lanthana alumina powder.
A lanthanum nitrate solution was prepared by dissolving 5433 grams of lanthanum nitrate crystals (37.6%
La2O3) in 56.77 liters of water and adding ln2.96 kilograms of an alumina filter cake having a solids content of 31% made by the procedure described in U.S.
Patent No. 4,371,513 to Sanchez et al. The resulting slurry was then spray dried using a vane wheel revolving at 18,000 rpm with an inlet temperature of 800F (427C) and an outlet temperature of 300F (149C). The spray dried powder has a TV of 8.24~ and a total rare earth oxide content of 6.06%.
This resulting lanthana containing powder was calcined for one hour at 2300F (1260C) to produce a powder having a water pore volume of 0.905 cc/g, a BET (N2) surface area of 44 m /g, and an alpha-alumina content of 4.5~.
Example 2 This example illustrates the preparation of a ceria activated lanthana alumina powder.
The lanthana alumina powder of Example 1 in an amount of 2825 grams was impregnated to full incipient wetness (2555 ml.) with a solution prepared by diluting 355.2 grams of a cerous nitrate solution (24.6% CeO2) with deionized water. The nominal CeO2 level was 3~. This was dried at 275F (135C) and subsequently activated for one hour at 2200F (1204C). The resulting activated powder had a water pore volume of 0.95 cc/g, a TV of 0.34~, an alpha-alumina content of 4.9% and a RET (N2) surface area of 37 m /g.
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Example 3 This example illustrates the preparation of washcoat powder containing 6% platinum/rhodium (weight ratio of 19/1) to be identified as Powder A.
The lanthana-ceria alumina powder of Example 2 in an amount of 600 grams (dry basis) was impregnated to full incipient wetness (572 ml.) with a solution prepared by mixing 379.07 grams of (NH4)6 Pt(SO3)~ solution (9.598~ Pt), 43.77 grams of Rh(NO3)3 solution (4.375%
Rh), 6 grams of dibasic ammonium citrate and then diluting with deionized water. The impregnated powder was allowed to stand in a sealed polyethylene bag for one hour prior to drying at 275F (135C). The dried powder was activated in air at 1000F (538C) for one hour and it will be referred to hereafter as Powder A.
Example 4 This example illustrates the preparation of a washcoat powder containing 4% platinum/rhodium (weight ratio of 19/1) to be identified as Powder B .
The lanthana-ceria alumina powder of Example 2 in an amount of 200 grams was impregnated to full incipient wetness (191 ml.) with a solution prepared by mixing 82.48 grams of (NH4)6 Pt(SO3)4 solution (9.598~ Pt), 9.524 grams of Rh(NO3)3 solution (4.375% Rh), 2 grams of dibasic ammonium citrate and then diluting with deionized water. The impreganted powder was allowed to stand in a sealed polyethylene bag for one hour prior to drying at 275F (135C). The dried powder was activated in air at 1000F (538C) for one hour and it will be referred to hereafter as Powder B.
Example 5 This example illustrates the preparation o~ the Cr2O3 component of the catalyst composition of this invention to be identified as Powder C.
, - 20 -~ 9 S~
Chromic acetate in an amount of 1000 grams was decomposed by heating to 1200F (649C) in air and then screening to a particle siæe of less than or equal to 250 microns followed by activation at 2000F (1093C) for one hour. This Cr2O3 powder has a BET (N2) surface area of 5 m /g and will be referred to hereafter as Powder C.
Example 6 This example illustrates the preparation of a monolithic combustion catalyst utilizing washcoat Powders A and C.
Powder A as prepared in Example 3 in an amount of 120 grams was ball milled with 255 grams of deionized water for 18 hours. The resulting slip had a pH of 4.54. A
second slip was made with 32 grams of Powder C as prepared in Example 5 which was ball milled with 106 grams of deionized water for 18 hours. The resulting slip had a pH
of 6.5. The two slips were mixed in a 3 to 1 ratio (on a solids basis) such that the resulting noble metal concentration of the dried slip when applied to a monolith would be 4.5~. The mixed slip had a pH of 4.59 and a viscosity of 700 centipoise at a solids content of 3.18%.
Mullite aluminum titanate (MAT) monoliths of 3.17"
diameter and 1/2~ thickness (obtained from Corning Glass) having nominally 16 cells per square inch were double coated with drying at 350F (177C) between coats. The coated units were finally activated in a flow of 5~
hydrogen balance nitrogen at 725-750F (385-399C) for 2 hours. The washcoat thickness was calculated to be 53 microns.
Example 7 This example illustrates the preparation of a monolithic combustion catalyst utilizing washcoat Powders B and C.
~z~3S~7~
Powder B as prepared in Example 4 in an amount of 75 grams was ball milled with 159 grams of deionized water for 18 hours. A second slip was made with 30 grams of Powder C as prepared in Example 5 which was ball milled with 64 grams of deionized water for 18 hours. The resulting second slip had a pH of 6. 57 ~ The two slips were mixed in a 3 to 1 ratio (on a solids basis) such that the resulting noble metal concentration of the dried slip when applied to a monolith would be 3~ The mixed slip had a pH of 4~45 at a solids content of 30~6~o Mullite alumina titanate (MAT) monoliths of 3~17~ diameter and 1/2~ thickness (obtained from Corning Glass) having nominally 64 cells per square inch were double coated with drying at 350F (177C) between coats. The coated units were finally activated in a flow of 5% hydrogen balance nitrogen at 725-750F (385-399C) for 2 hours. The washcoat thickness was calculated to be 49 microns.
Example 8 A test unit was employed having 10 monolith catalyst sections each having a diameter of 8 ~ 05 cm and a thickness of 1~27 cm. The first four monolith sections had 16 cells per square inch and the remaining 6 sections downstream had 64 cells per square inch. The monolith sections were arranged in pairs with reaction space provided between each pair. The 16 cell monolith catalysts were prepared according to Example 6 and the 64 cell monolith catalyst was prepared according to Example 7. The first four and last two monolith sections had been previously run in the device for about 8-1/2 hours. The fifth through eighth units had been used for about 23-1/2 hours.
During the period of the test the air fuel ratio was varied around the stoichiometric point and especially into the slightly lean region. After the system reached a ~ 22 ~
~ Z~ 5~7~
steady-state temperature the temperature in the reaction zone following the first four monoliths was about 2400F
(1316C) and in the reaction zone before the last two monoliths it was about 2050F (1121C). Thus the catalysts were experiencing temperatures of at least 2000F (1093C) throughout the test. The air flow rate was approximately 150 SCFM, the fuel emulsion was supplied at 0.36-0.38 gallon/minute and the system pressure was approximately 500 psi. The results are set forth in Table 1.
Table 1 Time CO 2 UHC Nx Equivalence Hr:min ~ ppm p~ Ratio 1:23 60 0.1 6 90 1.057 2:45 0 2 0.5 118 0.99 1 UHC is unburned hydrocarbons 2 Equivalence ratio relates to the amount of air used compared to the theoretical, stoichiometric amount which is 1Ø For values greater than 1.0, the mixture is rich and for values less than 1.0, the mixture is lean. The target is to operate at 1Ø
The results show that after 2 hours and ~5 minutes on stream the catalysts were still effective since the final CO was a low 0 ppm, the UHC was only 0.5 ppm and the NOX
was 118 ppm. This amount of NOX cannot be totally eliminated since there is always some nitrogen present as nitrogen compounds in the fuel.
The catalysts used in this system are also advantageous since they are capable of being lit off after repeated usage.
9S'~ ~
It is understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of this invention.
. . - 24 -
Claims (22)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A high temperature stable catalyst comprising a mixture of:
(a) fine particles of a base metal or base metal oxide selected from the group consisting of chromium, hafnium, niobium, chromium oxide, hafnium oxide, niobium oxide and mixtures thereof; and (b) composite particles of a ceria promoted, high temperature chemically stabilized refractory oxide powder having at least one platinum group metal thereon, said composite particles serving as a bonding vehicle for said base metal or base metal oxide particles whereby said base metal or base metal oxide particles are dispersed throughout the mixture and whereby said base metal or base metal oxide exists in a fine particulate form.
(a) fine particles of a base metal or base metal oxide selected from the group consisting of chromium, hafnium, niobium, chromium oxide, hafnium oxide, niobium oxide and mixtures thereof; and (b) composite particles of a ceria promoted, high temperature chemically stabilized refractory oxide powder having at least one platinum group metal thereon, said composite particles serving as a bonding vehicle for said base metal or base metal oxide particles whereby said base metal or base metal oxide particles are dispersed throughout the mixture and whereby said base metal or base metal oxide exists in a fine particulate form.
2. A catalyst according to claim 1, wherein the refrac-tory oxide powder is alumina, alumina powder which has been calcined at a temperature near incipient alpha alumina forma-tion, silica-alumina or zirconia.
3. A catalyst according to claim 1, wherein the high temperature stable refractory oxide powder is a lanthana stabilized alumina, a lanthana rich rare earth oxide stabilized alumina or a barium oxide stabilized alumina.
4. A catalyst according to claim 1, wherein the base metal or base metal oxide comprise about 15% to 90% by weight of the total weight.
5. A catalyst according to claim 1, wherein the platinum group metal comprises 0.05% to 10% by weight of the total weight.
6. A catalyst according to claim 1, further comprising a substrate on which said catalyst composition is coated.
7. A catalyst according to claim 6, wherein the substrate is a honeycomb.
8. A catalyst according to claim 6, wherein the substrate is in particulate form.
9. A catalyst according to claim 6, wherein the substrate is a fibrous composite.
10. A catalyst according to claim 1, wherein said particles of a base metal or base metal oxide have a particle size of less than 10 microns.
11. A method of making a high temperature stable catalyst comprising:
forming a catalyst washcoat by mixing together (a) a first slip containing composite particles comprising at least one platinum group metal on a ceria promoted, high temperature chemically stabilized refractory oxide powder, and (b) a second slip containing fine particles of a base metal or base metal oxide selected from the group consisting of chromium, hafnium, niobium, chromium oxide, hafnium oxide, niobium oxide and mixtures thereof;
applying the washcoat to a rigid catalyst support substrate capable of maintaining its shape and strength at high tempera-tures; and heating the coated support to remove volatile materials wherein said composite particles serve as a bonding vehicle for said base metal or base metal oxide particles and wherein said base metal or base metal oxide exists in a fine particulate form.
forming a catalyst washcoat by mixing together (a) a first slip containing composite particles comprising at least one platinum group metal on a ceria promoted, high temperature chemically stabilized refractory oxide powder, and (b) a second slip containing fine particles of a base metal or base metal oxide selected from the group consisting of chromium, hafnium, niobium, chromium oxide, hafnium oxide, niobium oxide and mixtures thereof;
applying the washcoat to a rigid catalyst support substrate capable of maintaining its shape and strength at high tempera-tures; and heating the coated support to remove volatile materials wherein said composite particles serve as a bonding vehicle for said base metal or base metal oxide particles and wherein said base metal or base metal oxide exists in a fine particulate form.
12. A method according to claim 11, wherein the refractory oxide powder is alumina, alumina powder which has been calcined at a temperature near incipient alpha alumina formation, silica-alumina or zirconia.
13. A method according to claim 11, wherein the high temperature stable refractory oxide is a lanthana stabilized alumina, a lanthana rich rare earth oxide stabilized alumina or a barium oxide stabilized alumina.
14. A method according to claim 11, wherein the base metal or metal oxide comprise about 15% to 90% by weight of the total solids content of the washcoat and the platinum group metal comprises 0.05% to 10% by weight of the total solids content of the washcoat.
15. A method according to claim 11, further comprising activating the catalyst in a reducing atmosphere.
16. A method of making a high temperature stable catalyst comprising:
forming a paste mixture by mixing together (a) composite particles comprising at least one platinum group metal on a ceria promoted, high temperature chemically stabilized refractory oxide powder;
(b) fine particles of a base metal or base metal oxide selected from the group consisting of chromium, hafnium, niobium, chromium oxide, hafnium oxide, niobium oxide and mixtures thereof; and (c) water;
forming the paste into a catalyst shape; and calcining the shaped catalyst whereby said composite particles serve as a bonding vehicle for said base metal or base metal oxide particles and said base metal or base metal oxide particles are dispersed throughout the mixture and whereby said base metal or base metal oxide exists in a fine particulate form.
forming a paste mixture by mixing together (a) composite particles comprising at least one platinum group metal on a ceria promoted, high temperature chemically stabilized refractory oxide powder;
(b) fine particles of a base metal or base metal oxide selected from the group consisting of chromium, hafnium, niobium, chromium oxide, hafnium oxide, niobium oxide and mixtures thereof; and (c) water;
forming the paste into a catalyst shape; and calcining the shaped catalyst whereby said composite particles serve as a bonding vehicle for said base metal or base metal oxide particles and said base metal or base metal oxide particles are dispersed throughout the mixture and whereby said base metal or base metal oxide exists in a fine particulate form.
17. A method according to claim 16, wherein the paste is extruded to form either small individual extrudate particles or large, porous monolith bodies.
18. A method according to claim 16, wherein the paste is formed into spherical particles.
19. A washcoat composition for application to a support to produce a high temperature stable catalyst comprising a slip mixture of (a) composite particles comprising at least one platinum group metal on a ceria promoted, high temperature chemically stabilized refractory oxide powder, and (b) fine particles of a base metal or base metal oxide selected from the group consisting of chromium, hafnium, niobium, chromium oxide, hafnium oxide, niobium oxide, and mixtures thereof, said composite particles being capable upon heating of serving as a bonding vehicle for said base metal or base metal oxide particles whereby said base metal or base metal oxide particles are dispersed throughout the mixture and whereby said base metal or base metal oxide exists in a fine particulate form.
20. A washcoat composition according to claim 19, wherein the refractory oxide powder is alumina, alumina powder which has been calcined at a temperature near incipient alpha alumina formation, silica-alumina or zirconia.
21. A washcoat composition according to claim 19, wherein the high temperature stable refractory oxide powder is a lanthana stabilized alumina, a lanthana rich rare earth oxide stabilized alumina or a barium oxide stabilized alumina.
22. A washcoat composition according to claim 19, wherein the base metal or metal oxide comprise about 15% to 90% by weight of the total solids content of the washcoat and the platinum group metal comprises 0.05% to 10% by weight of the total solids content of the washcoat.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US06/640,874 US4585752A (en) | 1984-08-15 | 1984-08-15 | Catalyst composition for ultra high temperature operation |
US640,874 | 1984-08-15 |
Publications (1)
Publication Number | Publication Date |
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CA1249571A true CA1249571A (en) | 1989-01-31 |
Family
ID=24570028
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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CA000484228A Expired CA1249571A (en) | 1984-08-15 | 1985-06-17 | Catalyst composition for ultra high temperature operation |
Country Status (5)
Country | Link |
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US (1) | US4585752A (en) |
EP (1) | EP0171640A3 (en) |
JP (1) | JPS6154240A (en) |
AU (1) | AU572060B2 (en) |
CA (1) | CA1249571A (en) |
Families Citing this family (44)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0130835B1 (en) * | 1983-07-01 | 1990-05-02 | Hitachi, Ltd. | High temperature stable catalyst, process for preparing same and process for conducting chemical reaction using same |
FR2584388B1 (en) * | 1985-07-03 | 1991-02-15 | Rhone Poulenc Spec Chim | COMPOSITION BASED ON CERIC OXIDE, ITS PREPARATION AND USES THEREOF |
US4714694A (en) * | 1986-06-30 | 1987-12-22 | Engelhard Corporation | Aluminum-stabilized ceria catalyst compositions, and methods of making the same |
JPH0626672B2 (en) * | 1987-03-05 | 1994-04-13 | 株式会社豊田中央研究所 | Exhaust purification catalyst and method of manufacturing the same |
US4977128A (en) * | 1987-12-29 | 1990-12-11 | Babcock-Hitachi Kabushiki Kaisha | Catalyst for combustion and process for producing same |
EP0495534A3 (en) * | 1988-03-12 | 1992-10-07 | Akira C/O Kohgakuin University Igarashi | Catalyst for steam reforming of hydrocarbon |
EP0383636A1 (en) * | 1989-02-17 | 1990-08-22 | Nippon Shokubai Co., Ltd. | Carrier for catalyst and method for production thereof |
US5741596A (en) * | 1989-02-21 | 1998-04-21 | Boeing North American, Inc. | Coating for oxidation protection of metal surfaces |
GB2234450A (en) * | 1989-07-25 | 1991-02-06 | Uop Ltd | Low temperature oxidation catalysts |
US4977130A (en) * | 1989-09-05 | 1990-12-11 | Texaco Inc. | Compositions involving V2 O3 -Al2 O3 -TiO2 |
JP2692382B2 (en) * | 1990-12-21 | 1997-12-17 | 松下電器産業株式会社 | Speech recognition method |
JP2879989B2 (en) * | 1991-03-22 | 1999-04-05 | 松下電器産業株式会社 | Voice recognition method |
GB9226434D0 (en) * | 1992-12-18 | 1993-02-10 | Johnson Matthey Plc | Catalyst |
US5565399A (en) * | 1994-06-29 | 1996-10-15 | Engelhard Corp | Co oxidation promoter and use thereof for catalytic cracking |
KR100416735B1 (en) * | 1995-10-09 | 2004-03-26 | 삼성전기주식회사 | Catalyst for purifying exhaust gas from car and method for preparing thereof |
US6335305B1 (en) * | 1999-01-18 | 2002-01-01 | Kabushiki Kaisha Toyota Chuo Kenkyusho | Catalyst for purifying exhaust gas |
US20030039826A1 (en) * | 2000-03-20 | 2003-02-27 | Sun Edward I. | Conformable and die-cuttable biaxially oriented films and labelstocks |
US7641875B1 (en) * | 2000-11-15 | 2010-01-05 | Catalytic Solutions, Inc. | Mixed-phase ceramic oxide three-way catalyst formulations and methods for preparing the catalysts |
US6455182B1 (en) * | 2001-05-09 | 2002-09-24 | Utc Fuel Cells, Llc | Shift converter having an improved catalyst composition, and method for its use |
US20030065235A1 (en) * | 2001-09-24 | 2003-04-03 | Allison Joe D. | Oxidative dehydrogenation of alkanes to olefins using an oxide surface |
US20030186805A1 (en) * | 2002-03-28 | 2003-10-02 | Vanderspurt Thomas Henry | Ceria-based mixed-metal oxide structure, including method of making and use |
JP4019357B2 (en) * | 2002-05-02 | 2007-12-12 | 日産自動車株式会社 | Method for producing exhaust gas purification catalyst powder and method for producing exhaust gas purification catalyst |
US7001867B2 (en) * | 2002-05-21 | 2006-02-21 | Conocophillips Company | Rare earth aluminates and gallates supported rhodium catalysts for catalytic partial oxidation of hydrocarbons |
AU2003295465A1 (en) * | 2002-11-11 | 2004-06-03 | Conocophillips Company | Stabilized alumina supports, catalysts made therefrom, and their use in partial oxidation |
US20050265920A1 (en) * | 2002-11-11 | 2005-12-01 | Conocophillips Company | Supports and catalysts comprising rare earth aluminates, and their use in partial oxidation |
US6932848B2 (en) * | 2003-03-28 | 2005-08-23 | Utc Fuel Cells, Llc | High performance fuel processing system for fuel cell power plant |
US8277773B2 (en) | 2004-02-13 | 2012-10-02 | Velocys Corp. | Steam reforming method |
US7722854B2 (en) * | 2003-06-25 | 2010-05-25 | Velocy's | Steam reforming methods and catalysts |
JP2005185969A (en) * | 2003-12-25 | 2005-07-14 | Nissan Motor Co Ltd | High heat-resistant catalyst and production method therefor |
JP3912377B2 (en) * | 2003-12-25 | 2007-05-09 | 日産自動車株式会社 | Method for producing exhaust gas purification catalyst powder |
JP4547930B2 (en) * | 2004-02-17 | 2010-09-22 | 日産自動車株式会社 | Catalyst, catalyst preparation method and exhaust gas purification catalyst |
JP4547935B2 (en) * | 2004-02-24 | 2010-09-22 | 日産自動車株式会社 | Exhaust gas purification catalyst, exhaust gas purification catalyst, and catalyst manufacturing method |
JP4513384B2 (en) * | 2004-03-31 | 2010-07-28 | 日産自動車株式会社 | High heat-resistant exhaust gas purification catalyst and method for producing the same |
JP5200315B2 (en) * | 2004-12-22 | 2013-06-05 | 日産自動車株式会社 | Exhaust gas purification catalyst and method for producing exhaust gas purification catalyst |
US8648006B2 (en) * | 2005-10-13 | 2014-02-11 | Velocys, Inc. | Electroless plating in microchannels |
US20070184974A1 (en) * | 2006-02-06 | 2007-08-09 | Bates Stephen C | High temperature metal-on-oxide-ceramic catalysts |
US20100190640A1 (en) * | 2007-06-27 | 2010-07-29 | Takeshi Nobukawa | Catalytic support and exhaust-gas converting catalyst (as amended) |
US8114354B2 (en) * | 2007-12-18 | 2012-02-14 | Basf Corporation | Catalyzed soot filter manufacture and systems |
US8038954B2 (en) * | 2008-02-14 | 2011-10-18 | Basf Corporation | CSF with low platinum/palladium ratios |
US20110003085A1 (en) * | 2008-04-04 | 2011-01-06 | Carrier Corporation | Production Of Tailored Metal Oxide Materials Using A Reaction Sol-Gel Approach |
WO2010114561A1 (en) * | 2009-04-03 | 2010-10-07 | Carrier Corporation | Production of tailored metal oxide materials using a reaction sol-gel approach |
US10792647B2 (en) | 2009-04-21 | 2020-10-06 | Johnson Matthey Public Limited Company | Base metal catalysts for the oxidation of carbon monoxide and volatile organic compounds |
IN2013MU04120A (en) | 2013-12-30 | 2015-08-07 | Indian Oil Corp Ltd | |
US20200055030A1 (en) * | 2016-11-17 | 2020-02-20 | The Regents Of The University Of California | HIGH TAR CONVERSION PERFORMANCE OF A Nl-FE-MGO CATALYST |
Family Cites Families (24)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3940923A (en) * | 1971-05-13 | 1976-03-02 | Engelhard Minerals & Chemicals Corporation | Method of operating catalytically supported thermal combustion system |
US3928961A (en) * | 1971-05-13 | 1975-12-30 | Engelhard Min & Chem | Catalytically-supported thermal combustion |
US3789022A (en) * | 1971-08-19 | 1974-01-29 | Diamond Shamrock Corp | Catalyst for oxidation of hydrocarbons and carbon monoxide |
US3846979A (en) * | 1971-12-17 | 1974-11-12 | Engelhard Min & Chem | Two stage combustion process |
US4029602A (en) * | 1973-05-22 | 1977-06-14 | Societe Lyonnaise Des Applications Catalytiques | Catalyst system for catalytic heaters |
US4056489A (en) * | 1973-12-10 | 1977-11-01 | Engelhard Minerals & Chemicals Corporation | High temperature stable catalyst composition and method for its preparation |
US3966391A (en) * | 1973-12-10 | 1976-06-29 | Engelhard Minerals & Chemicals Corporation | Method of combustion using high temperature stable catalysts |
US4021185A (en) * | 1973-12-10 | 1977-05-03 | Engelhard Minerals & Chemicals Corporation | Compositions and methods for high temperature stable catalysts |
US3945946A (en) * | 1973-12-10 | 1976-03-23 | Engelhard Minerals & Chemicals Corporation | Compositions and methods for high temperature stable catalysts |
US3966790A (en) * | 1973-12-10 | 1976-06-29 | Engelhard Minerals & Chemicals Corporation | Compositions and methods for high temperature stable catalysts |
US3956188A (en) * | 1973-12-10 | 1976-05-11 | Engelhard Minerals & Chemicals Corporation | Compositions and methods for high temperature stable catalysts |
US3932309A (en) * | 1974-06-05 | 1976-01-13 | W. R. Grace & Co. | Auto exhaust catalysts prepared from sulfite treated platinum and palladium salt solutions |
GB1604246A (en) * | 1977-06-08 | 1981-12-02 | Johnson Matthey Co Ltd | Catalysts for oxidation and reduction processes |
US4220559A (en) * | 1978-02-14 | 1980-09-02 | Engelhard Minerals & Chemicals Corporation | High temperature-stable catalyst composition |
US4170573A (en) * | 1978-04-07 | 1979-10-09 | W. R. Grace & Co. | Rare earth and platinum group metal catalyst compositions |
GB2027358B (en) * | 1978-07-12 | 1983-04-27 | Nippon Catalytic Chem Ind | Exhaust gas purification catalysts |
DE2853547C2 (en) * | 1978-12-12 | 1983-11-03 | Degussa Ag, 6000 Frankfurt | Carrier for catalysts with cross-flow effect and use, traversed by flow channels |
DE2907106C2 (en) * | 1979-02-23 | 1985-12-19 | Degussa Ag, 6000 Frankfurt | Catalytic converter and its use for cleaning exhaust gases from internal combustion engines |
JPS56124442A (en) * | 1980-03-06 | 1981-09-30 | Toyota Central Res & Dev Lab Inc | Catalyst for cleaning of exhaust gas |
US4303552A (en) * | 1980-05-27 | 1981-12-01 | W. R. Grace & Co. | Diesel exhaust catalyst |
FR2483804A2 (en) * | 1980-06-04 | 1981-12-11 | Applic Catalytiques Ste Ly | NEW CONTACT MASS FOR HETEROGENEOUS CATALYSIS |
US4426320A (en) * | 1981-01-27 | 1984-01-17 | W. R. Grace & Co. | Catalyst composition for exhaust gas treatment |
US4930454A (en) * | 1981-08-14 | 1990-06-05 | Dresser Industries, Inc. | Steam generating system |
US4438219A (en) * | 1981-10-28 | 1984-03-20 | Texaco Inc. | Alumina catalyst stable at high temperatures |
-
1984
- 1984-08-15 US US06/640,874 patent/US4585752A/en not_active Expired - Fee Related
-
1985
- 1985-06-17 CA CA000484228A patent/CA1249571A/en not_active Expired
- 1985-07-18 EP EP85108985A patent/EP0171640A3/en not_active Withdrawn
- 1985-07-18 AU AU45146/85A patent/AU572060B2/en not_active Ceased
- 1985-08-09 JP JP60174398A patent/JPS6154240A/en active Pending
Also Published As
Publication number | Publication date |
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EP0171640A2 (en) | 1986-02-19 |
AU4514685A (en) | 1986-02-20 |
EP0171640A3 (en) | 1987-03-18 |
US4585752A (en) | 1986-04-29 |
JPS6154240A (en) | 1986-03-18 |
AU572060B2 (en) | 1988-04-28 |
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