CA2010970A1 - Catalyst for the selective reduction of nitrogen oxides with ammonia - Google Patents
Catalyst for the selective reduction of nitrogen oxides with ammoniaInfo
- Publication number
- CA2010970A1 CA2010970A1 CA002010970A CA2010970A CA2010970A1 CA 2010970 A1 CA2010970 A1 CA 2010970A1 CA 002010970 A CA002010970 A CA 002010970A CA 2010970 A CA2010970 A CA 2010970A CA 2010970 A1 CA2010970 A1 CA 2010970A1
- Authority
- CA
- Canada
- Prior art keywords
- catalyst
- components
- component
- oxide
- paste
- 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.)
- Abandoned
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 75
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 39
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 title claims abstract description 39
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 10
- 230000009467 reduction Effects 0.000 title claims abstract description 10
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 35
- 238000004898 kneading Methods 0.000 claims abstract description 15
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims abstract description 11
- 238000001035 drying Methods 0.000 claims abstract description 8
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 7
- 238000001354 calcination Methods 0.000 claims abstract description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 6
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 5
- 239000002243 precursor Substances 0.000 claims abstract description 5
- 239000000126 substance Substances 0.000 claims abstract description 5
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 4
- 229910052796 boron Inorganic materials 0.000 claims abstract description 4
- 229910052802 copper Inorganic materials 0.000 claims abstract description 4
- 229910052742 iron Inorganic materials 0.000 claims abstract description 4
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 4
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 4
- 229910052727 yttrium Inorganic materials 0.000 claims abstract description 4
- 229910052684 Cerium Inorganic materials 0.000 claims abstract description 3
- 229910052788 barium Inorganic materials 0.000 claims abstract description 3
- 229910052746 lanthanum Inorganic materials 0.000 claims abstract description 3
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 3
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 3
- 239000000203 mixture Substances 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 19
- 230000008569 process Effects 0.000 claims description 13
- 239000002253 acid Substances 0.000 claims description 11
- 150000007513 acids Chemical class 0.000 claims description 10
- 150000003839 salts Chemical class 0.000 claims description 10
- 239000007858 starting material Substances 0.000 claims description 10
- 238000000465 moulding Methods 0.000 claims description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- -1 oxides Chemical class 0.000 claims description 6
- 239000003795 chemical substances by application Substances 0.000 claims description 5
- 239000011964 heteropoly acid Substances 0.000 claims description 5
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 5
- 239000010937 tungsten Substances 0.000 claims description 5
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 4
- 239000000654 additive Substances 0.000 claims description 4
- 238000001125 extrusion Methods 0.000 claims description 4
- 229910052751 metal Inorganic materials 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 4
- 239000011733 molybdenum Substances 0.000 claims description 4
- 239000011574 phosphorus Substances 0.000 claims description 4
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 3
- 239000011230 binding agent Substances 0.000 claims description 3
- 239000012018 catalyst precursor Substances 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- 150000004679 hydroxides Chemical class 0.000 claims description 3
- 150000002739 metals Chemical class 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 239000010955 niobium Substances 0.000 claims description 3
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 3
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical class [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 claims description 3
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 claims description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 2
- 239000003570 air Substances 0.000 claims description 2
- 239000012080 ambient air Substances 0.000 claims description 2
- 150000003863 ammonium salts Chemical class 0.000 claims description 2
- 239000007864 aqueous solution Substances 0.000 claims description 2
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 2
- 238000000748 compression moulding Methods 0.000 claims description 2
- 238000005470 impregnation Methods 0.000 claims description 2
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 2
- 238000012986 modification Methods 0.000 claims description 2
- 230000004048 modification Effects 0.000 claims description 2
- 239000010703 silicon Substances 0.000 claims description 2
- 239000000919 ceramic Substances 0.000 claims 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 claims 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims 1
- 239000006057 Non-nutritive feed additive Substances 0.000 abstract 1
- 239000000306 component Substances 0.000 description 20
- 239000000243 solution Substances 0.000 description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 15
- 239000008367 deionised water Substances 0.000 description 11
- 229910021641 deionized water Inorganic materials 0.000 description 11
- 239000000463 material Substances 0.000 description 10
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 9
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 description 9
- 241000264877 Hippospongia communis Species 0.000 description 8
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 description 8
- XAYGUHUYDMLJJV-UHFFFAOYSA-Z decaazanium;dioxido(dioxo)tungsten;hydron;trioxotungsten Chemical compound [H+].[H+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O XAYGUHUYDMLJJV-UHFFFAOYSA-Z 0.000 description 8
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000006722 reduction reaction Methods 0.000 description 8
- 239000010936 titanium Substances 0.000 description 8
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 description 7
- 239000007789 gas Substances 0.000 description 7
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 7
- 239000011148 porous material Substances 0.000 description 7
- 229960005196 titanium dioxide Drugs 0.000 description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 239000011872 intimate mixture Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 229910052719 titanium Inorganic materials 0.000 description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 5
- 229920002678 cellulose Polymers 0.000 description 5
- 235000010980 cellulose Nutrition 0.000 description 5
- 239000003365 glass fiber Substances 0.000 description 5
- 239000001913 cellulose Substances 0.000 description 4
- 239000004927 clay Substances 0.000 description 4
- 230000000875 corresponding effect Effects 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 239000003546 flue gas Substances 0.000 description 4
- 239000004310 lactic acid Substances 0.000 description 4
- 235000014655 lactic acid Nutrition 0.000 description 4
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 description 4
- 238000007493 shaping process Methods 0.000 description 4
- 239000003381 stabilizer Substances 0.000 description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 3
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 3
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 3
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 3
- 239000004793 Polystyrene Substances 0.000 description 3
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 3
- 239000012190 activator Substances 0.000 description 3
- 235000011114 ammonium hydroxide Nutrition 0.000 description 3
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 description 3
- 229940010552 ammonium molybdate Drugs 0.000 description 3
- 235000018660 ammonium molybdate Nutrition 0.000 description 3
- 239000011609 ammonium molybdate Substances 0.000 description 3
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Chemical compound [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 3
- 230000032823 cell division Effects 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 3
- OPQARKPSCNTWTJ-UHFFFAOYSA-L copper(ii) acetate Chemical compound [Cu+2].CC([O-])=O.CC([O-])=O OPQARKPSCNTWTJ-UHFFFAOYSA-L 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000007774 longterm Effects 0.000 description 3
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000004408 titanium dioxide Substances 0.000 description 3
- 229910001930 tungsten oxide Inorganic materials 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 229910052770 Uranium Inorganic materials 0.000 description 2
- XHCLAFWTIXFWPH-UHFFFAOYSA-N [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] XHCLAFWTIXFWPH-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052810 boron oxide Inorganic materials 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 2
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 2
- 238000010531 catalytic reduction reaction Methods 0.000 description 2
- 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 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 238000000975 co-precipitation Methods 0.000 description 2
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 229910001385 heavy metal Inorganic materials 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- XNHGKSMNCCTMFO-UHFFFAOYSA-D niobium(5+);oxalate Chemical compound [Nb+5].[Nb+5].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O XNHGKSMNCCTMFO-UHFFFAOYSA-D 0.000 description 2
- 229910000510 noble metal Inorganic materials 0.000 description 2
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 231100000572 poisoning Toxicity 0.000 description 2
- 230000000607 poisoning effect Effects 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- DLYUQMMRRRQYAE-UHFFFAOYSA-N tetraphosphorus decaoxide Chemical compound O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 2
- 150000003608 titanium Chemical class 0.000 description 2
- DNYWZCXLKNTFFI-UHFFFAOYSA-N uranium Chemical compound [U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U][U] DNYWZCXLKNTFFI-UHFFFAOYSA-N 0.000 description 2
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 2
- 229910001935 vanadium oxide Inorganic materials 0.000 description 2
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonium chloride Substances [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 1
- 239000004254 Ammonium phosphate Substances 0.000 description 1
- 101100352919 Caenorhabditis elegans ppm-2 gene Proteins 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- IAYPIBMASNFSPL-UHFFFAOYSA-N Ethylene oxide Chemical compound C1CO1 IAYPIBMASNFSPL-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 229920001131 Pulp (paper) Polymers 0.000 description 1
- 102100035115 Testin Human genes 0.000 description 1
- 101710070533 Testin Proteins 0.000 description 1
- 241000030538 Thecla Species 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- LXASOGUHMSNFCR-UHFFFAOYSA-D [V+5].[V+5].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O Chemical compound [V+5].[V+5].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O LXASOGUHMSNFCR-UHFFFAOYSA-D 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229940010556 ammonium phosphate Drugs 0.000 description 1
- 229910000148 ammonium phosphate Inorganic materials 0.000 description 1
- 235000019289 ammonium phosphates Nutrition 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- 238000007630 basic procedure Methods 0.000 description 1
- 235000012216 bentonite Nutrition 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 125000002057 carboxymethyl group Chemical group [H]OC(=O)C([H])([H])[*] 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 description 1
- 229910000420 cerium oxide Inorganic materials 0.000 description 1
- VGBWDOLBWVJTRZ-UHFFFAOYSA-K cerium(3+);triacetate Chemical compound [Ce+3].CC([O-])=O.CC([O-])=O.CC([O-])=O VGBWDOLBWVJTRZ-UHFFFAOYSA-K 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 230000001143 conditioned effect Effects 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- IYRDVAUFQZOLSB-UHFFFAOYSA-N copper iron Chemical compound [Fe].[Cu] IYRDVAUFQZOLSB-UHFFFAOYSA-N 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 description 1
- OHAVYOCBYILSBZ-UHFFFAOYSA-M dihydroxyboron;hydroxy(dioxo)tungsten Chemical compound O[B]O.O[W](=O)=O OHAVYOCBYILSBZ-UHFFFAOYSA-M 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- VEPSWGHMGZQCIN-UHFFFAOYSA-H ferric oxalate Chemical compound [Fe+3].[Fe+3].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O VEPSWGHMGZQCIN-UHFFFAOYSA-H 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000000499 gel Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 235000014413 iron hydroxide Nutrition 0.000 description 1
- 229910000398 iron phosphate Inorganic materials 0.000 description 1
- 159000000014 iron salts Chemical class 0.000 description 1
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 1
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 1
- 238000009533 lab test Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 235000010981 methylcellulose Nutrition 0.000 description 1
- 229910000476 molybdenum oxide Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Inorganic materials O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 description 1
- MAKKVCWGJXNRMD-UHFFFAOYSA-N niobium(5+);oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] MAKKVCWGJXNRMD-UHFFFAOYSA-N 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- OGUCKKLSDGRKSH-UHFFFAOYSA-N oxalic acid oxovanadium Chemical compound [V].[O].C(C(=O)O)(=O)O OGUCKKLSDGRKSH-UHFFFAOYSA-N 0.000 description 1
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 1
- PQQKPALAQIIWST-UHFFFAOYSA-N oxomolybdenum Chemical compound [Mo]=O PQQKPALAQIIWST-UHFFFAOYSA-N 0.000 description 1
- DCKVFVYPWDKYDN-UHFFFAOYSA-L oxygen(2-);titanium(4+);sulfate Chemical compound [O-2].[Ti+4].[O-]S([O-])(=O)=O DCKVFVYPWDKYDN-UHFFFAOYSA-L 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- DHRLEVQXOMLTIM-UHFFFAOYSA-N phosphoric acid;trioxomolybdenum Chemical compound O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.OP(O)(O)=O DHRLEVQXOMLTIM-UHFFFAOYSA-N 0.000 description 1
- IYDGMDWEHDFVQI-UHFFFAOYSA-N phosphoric acid;trioxotungsten Chemical compound O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.OP(O)(O)=O IYDGMDWEHDFVQI-UHFFFAOYSA-N 0.000 description 1
- 229910001392 phosphorus oxide Inorganic materials 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 239000002574 poison Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000011164 primary particle Substances 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- CGFYHILWFSGVJS-UHFFFAOYSA-N silicic acid;trioxotungsten Chemical compound O[Si](O)(O)O.O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1.O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1.O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1.O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 CGFYHILWFSGVJS-UHFFFAOYSA-N 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- VSAISIQCTGDGPU-UHFFFAOYSA-N tetraphosphorus hexaoxide Chemical compound O1P(O2)OP3OP1OP2O3 VSAISIQCTGDGPU-UHFFFAOYSA-N 0.000 description 1
- LLZRNZOLAXHGLL-UHFFFAOYSA-J titanic acid Chemical compound O[Ti](O)(O)O LLZRNZOLAXHGLL-UHFFFAOYSA-J 0.000 description 1
- 229910000349 titanium oxysulfate Inorganic materials 0.000 description 1
- 229910000348 titanium sulfate Inorganic materials 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 239000001993 wax Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 229910000166 zirconium phosphate Inorganic materials 0.000 description 1
- LEHFSLREWWMLPU-UHFFFAOYSA-B zirconium(4+);tetraphosphate Chemical compound [Zr+4].[Zr+4].[Zr+4].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LEHFSLREWWMLPU-UHFFFAOYSA-B 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
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
-
- 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
- B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
- B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
- B01J21/066—Zirconium or hafnium; Oxides or hydroxides thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
- B01D53/8628—Processes characterised by a specific catalyst
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9413—Processes characterised by a specific catalyst
- B01D53/9418—Processes characterised by a specific catalyst for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
-
- 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
- B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
- B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
- B01J21/063—Titanium; Oxides or hydroxides thereof
-
- 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
-
- 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
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
-
- 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
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
- B01J35/61—Surface area
-
- 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
- B01J37/08—Heat treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2062—Ammonia
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/207—Transition metals
- B01D2255/20707—Titanium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/207—Transition metals
- B01D2255/20723—Vanadium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/207—Transition metals
- B01D2255/20776—Tungsten
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/90—Physical characteristics of catalysts
- B01D2255/92—Dimensions
- B01D2255/9207—Specific surface
-
- 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
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
- B01J35/61—Surface area
- B01J35/613—10-100 m2/g
-
- 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
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
- B01J35/61—Surface area
- B01J35/615—100-500 m2/g
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Combustion & Propulsion (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
In addition to titanium oxide as component A), a catalyst for the selective reduction of nitrogen oxides with ammonia contains at least one oxide of W, Si, B, Al, P, Zr, Ba, Y, La, Ce and at least one oxide of V, Nb, Mo, Fe, Cu as component B), the atomic ratio between the elements of components A) and B) being from 1 : 0.001 to 1. The catalysts can be obtained by kneading reactive titanium oxide having a high specific surface of, predominantly, anatase with the substances of component B) or precursors thereof with addition of processing aids to form a homogeneous kneaded paste, extruding this paste, drying the extrudate and calcining it in air at 300 to 800°C..
In addition to titanium oxide as component A), a catalyst for the selective reduction of nitrogen oxides with ammonia contains at least one oxide of W, Si, B, Al, P, Zr, Ba, Y, La, Ce and at least one oxide of V, Nb, Mo, Fe, Cu as component B), the atomic ratio between the elements of components A) and B) being from 1 : 0.001 to 1. The catalysts can be obtained by kneading reactive titanium oxide having a high specific surface of, predominantly, anatase with the substances of component B) or precursors thereof with addition of processing aids to form a homogeneous kneaded paste, extruding this paste, drying the extrudate and calcining it in air at 300 to 800°C..
Description
2~3~0970 The pr~sent invention relates to a catalyst for the selective reduction of nitrogen oxides with ammonia.
Nitrogen oxides which are formed in combustion processes are among the main causes of acid rain or photosmog and the ensuing damage to the environment. Along with fluorochlorocarbons, nitrogen oxides in particular are suspected of being responsible for the observed depletion of the ozone layer above the polar region.
Sources of nitrogen oxide emission are vehicle traffic, stationary combustion engines, power stations, thermal power stations, steam generators for industrial purposes and industrial production plants.
Although, in boiler-fired power stations, a reduction in the nitrogen oxide concentration of the exhaust gases can be obtained by using very pure fuels or by optimizing the combustion systems (primary measures), there are both technical and economic limits to these primary measures. Accordingly, secondary measures also have to be taken to keep to the legally stipulated emission limits. Secondary measures for nitrogen oxide reduction are, typically, catalytic reduction processes in which ammonia is generally used as a selective reducing agent.
Catalysts are know for reducing nitrogen oxide emission 2~ hy catalytic reduction. Thus, DE-AS 12 59 298, 12 53 685 and 11 15 230 describe oxidic catalysts with no noble metal content while DE-OS 22 14 604 describes oxidic catalysts containing noble metals.
Nitrogen oxides which are formed in combustion processes are among the main causes of acid rain or photosmog and the ensuing damage to the environment. Along with fluorochlorocarbons, nitrogen oxides in particular are suspected of being responsible for the observed depletion of the ozone layer above the polar region.
Sources of nitrogen oxide emission are vehicle traffic, stationary combustion engines, power stations, thermal power stations, steam generators for industrial purposes and industrial production plants.
Although, in boiler-fired power stations, a reduction in the nitrogen oxide concentration of the exhaust gases can be obtained by using very pure fuels or by optimizing the combustion systems (primary measures), there are both technical and economic limits to these primary measures. Accordingly, secondary measures also have to be taken to keep to the legally stipulated emission limits. Secondary measures for nitrogen oxide reduction are, typically, catalytic reduction processes in which ammonia is generally used as a selective reducing agent.
Catalysts are know for reducing nitrogen oxide emission 2~ hy catalytic reduction. Thus, DE-AS 12 59 298, 12 53 685 and 11 15 230 describe oxidic catalysts with no noble metal content while DE-OS 22 14 604 describes oxidic catalysts containing noble metals.
3~ DE-PS 24 S8 888 describes another catalyst which consists of an "intimate mixture" of the following components: A) titanium in the form of oxides, B) at least one metal from the group 2~
~-1 iron and vanadium in the form of oxides and/or from the group s-2 molybdenum, tungsten, nickel, cobalt, copper, chromium and uranium in the form of oxides C) tin in the form of oxides D) metals from the group consisting of beryllium, magnesium, zinc, boron, aluminium, yttrium, rare earth elements, silicon, niobium, antimony, bis-lo muth and manganese in the form of oxides.
The components are present in atomic ratios of A : B ~ C :
D of 1 : 0.01 to 10 : 0 to 0.2 0 to 0.15 nltrogen oxlde A catalyst having this composition is used for the-reduction ~ gas mixtures containing oxygen and ammonia at temperatures in the range from 150 to 550C and at space velocities of 300 to 100,000 h-1.
These catalysts may be produced by measures known per se. However, these measures must always guarantee that the components A) and B) and, optionally, C) can be obtained as an intimate mixture in the form of their oxides. The fol-lowing are mentioned as typical examples o~ such production processes:
la: homogeneous dissolving process lb: co-precipitation processes 2 : cGmbinations of the dissolving and precipitation processes 3 : mixed precipitate processes.
Solutions and/or precipitates, such as for example hydroxides or aqueous gels, are used as precursors of components A), B) and C), being intimately mixed and then subjected to calcination. The precursors are pyrolized, giving the desired intimate mixture of the oxides of the components critical to the catalysis process. The calcin-ation temperature has to be in the range from 300 to 800~C.
Below 300C, it is not possible to obtain an intimate 97~
mixture of the oxides and therefore no active catalyst;
above 800 C, sinterilly occurs and results in loss of the acti~e catalyst surface.
Ille starting mate~ials used for titanium as component A) include, for example, various titanium acids, titanium hydroxide and various titanium salts, such as halides, titanium sulfate, titanyl sulfate and the like. Organic compounds of titanium, for example titanium alkoxides, may also be used as starting material for the titanium. Titan-ium oxide in the calcined rutile or anatase form is not suitable.
The catalyst material described in DE-PS 35 31 809 is based on a further development of these catalyst production processes described in DE-AS 24 58 888. Titanium dioxide is used as starting material for the production of this catalyst material and is ground together with vanadium oxide and one or more oxides of the elements tungsten, molybdenum, phosphorus, chromium, copper, iron, uranium and then ~ bc~ed to at least one heat treatment. In ~his le~-$æea$~e~t, the tungsten and molybdPnum are completely or partly replaced by phosphorus in the form of its oxides or phosphates. The mills used are preferably eccentric disc mills and ring chamber mills. The calcination step takes place at a temperature in the range from 200 to 900C.
With all hitherto known catalysts of this type, com-ponents A) and B) (for example A = Ti; B = W, Mo. etc.) must be present in the form of an intimate mixture of their oxides. This mixture is then subjected to a shaping pro-cess from which the catalysts can be obtained in the form of loose material or honeycomb monoliths by compre5sion moulding or extrusion.
This means that shaping of the catalyst, for example by extrusion, has to be preceded by a process of which the object is to form the intimate mixture as starting materi-20~0970 al. Thls procedure, which is widely used at the present time, is attended by the followlng disadvantages:
- elaborate, multlstage, energy-intenslve process steps are necessary - the productlon of the lntlmate mixture ln accordance with DE-AS 24 58 888 is not environment-friendly on account of emission and wastewater problems;
- the operatlon of mills for grIndlng activatlon is energy-o lntenslve and requlres elaborate noise control measures and dust control systems;
- the preliminary process steps for formlng the lntlmate ~mixture are a serious cost factor in the production of the catalyst.
Accordingly the present invention greatly simplifies and, hence, dlstlnctly reduces the cost of catalyst productlon by 2U saving process steps in the productlon of so-called solld type catalysts~whlch conslst throughout of catalytically active materlal) for the selectlve reduction of nltrogen oxides in oxygen-containing exhaust gases in the presence of ammonia. In addltlon, the inventlon enables the~propertles~of the catalyst to be dlrectly and finely controlled through the management of the process.
~:
According to the present inventlon there ls provlded a catalyst for the selective reductlon of nitrogen oxides with ammonia contalning the followlng components: A) titanium oxide, 3U Bl) at least one oxide of tungsten,~sillcon, boron, aluminum, phosphorus, zirconium, barium, yttrium, lanthanum, cerium, and B2) at least one oxide of vanadium, nlobium, molybdenum, iron copper, wlth an atomlc ratlo between the elements of components A) and B) of 1 : 0.001 to 1 obtalned by lntenslvely kneadlng ~ 109~0 component A) in the form of a reactive high-surface titanlum oxide having a BET surface of 40 to 500 m2/g, whlch is completely or predomlnantly present ln the anatase modlfication, together wlth components sl) and s2) or thelr precursors, wlth the addition o of the additlves normally used for the compresslon moulding or extrusion of ceramlc pastes, moistening agents, supporting substances, blnders, mouldlng aids and. to form a homogeneous kneaded paste, extruding the kneaded paste to mouldings, drying the mouldlngs with a gradual increase in temperature to at most 60C and then calcinlng them with a stepwise lncrease in temperature in ambient air at:flnal lU temperatures ln the range from 300 to 800C. Suitably 2. A
catalyst is obtalned by using hydroxides, oxides, salts or heteropoly acids or salts thereof as starting material for components sl) and B2).
l!;
Thus according to the present invention certain titanium oxide materials are processed by kneading and there is.
no longer any need for the already known measures for the formation of on intimate oxlde mlxture.
Suitable titanium oxides are reactive high-surface titanium oxldes having a specific BET surface of from 40 to 500 preferably 50 to 300 and more preferably 75 to 150 m2/g whlch are completely or predominantly present:in anatase form, These 2r materials may be commercial products produced by precipation or ~ by flame hydrolysis. Apart 3U .
.
- - 4a -2~ 3~"3 ~ ~3 from tll~ir higll specific surface, these generally highly disperse products have a very narrow particle siz~ distri-bution witll an averaye primary particle size of the order of 30 ~m.
The individual elements of group B) may be used, for example, in the form of the following starting compounds:
tungsten oxide, ammonium para- or meta-tungstate, silicon dioxide, silicotungstic acid, silica, boron oxide, boric acid, aluminium oxide, phosphorus oxide, ammonium phos-phate, phosphotungstic acid, phosphomolybdic acid, zir-conium dioxide, zirconium phosphate, barium oxide, yttrium oxide, lanthanum oxide, cerium acetate, cerium nitrate, cerium oxide, borotungstic acid, vanadium oxide, vanadyl oxalate, ammonium metavanadate, vanadotungstic acids, vanadomolyhdic acids, vanadophosphomolybdic acids, phospho-vanadic acid, niobium oxide hydrate, niobium oxalate, niobium vanadic acids, ammonium molybdate, molybdenum oxide, iron oxide, iron phosphate, iron hydroxide, organic iron salts, such as iron oxalate, copper acetate, copper-(II) oxide, Cu-, Ce-, La-containing heteropoly acids, etc.
The substances mentioned may be used in the form of solutions or even in the form of solid substances.
Apart from the actual catalyst material, a number of additives known ~er se are required for the production of solld type the whol~ catalysts according to the invention.
Deionized water, aqueous ammonia solution, monoethan-olamine and alcohols may be used as the moistening agent.
Glass fibers of various sizes, for example, may be used as supporting materials.
Suitable binders, which provide the paste to be pro-duced with sufficient stability in the so-called green state after shaping, are cellulose derivatives such as, for example, carboxymethyl cellulose or even unsubstituted celluloses.
Polyethylene, polypropylene, polyvinyl alcoholl poly-~ 3 ethylene oxide, polyacrylamide or polystyrene may also be used as the binder.
To facilitate compression moulding or to improve extrudabillty, mouldlng aids and/or lubricants such as, for example, bentonites, aluminas, organlc acids, paraffin, waxes, ; silicone oils, are added.
Finally, the porosity (pore volume, pore size distribution) of the whole catalyst may be ad~usted as required by the addition of suitable air-~ntraining agents. ~dditives Lu such as these are, for example, finely divided carbons or wood pulp, which burn out at the calcination temperatures applied.
Kneading units are used for intensively kneading the starting materials to a homogeneous kneaded paste. Kneaders with 1~ sigma or masticator blades are preferred. The use of a certain titanium oxide in accordance with the invention in conjunction with an intensive kneading step for preparing the catalyst paste affords considerable advantages over the conventional production 2U process. Thus, there is no longer any need for elaborate environment polluting and, hence, expensive process steps. Co-precipitation and grinding processes for preparing an intimate oxids mixture are no longer necessary. This leads to a distinct reduction in production costs and also eliminates dependence on expensively produced starting materials.
2~
In addition, contraction, a key parameter in regard to the tendency of solid type catalysts to crack and in regard to their breaking strength, can be regulated as required by the use of suitable starting materials and by adaption of the kneading 3~ process in regard to intensity, temperature and time, including intermediate conditioning steps.
Thus according to one embodiment of the present invention the catalyst is obtained by mixing component A) and 3~
;~311Uf~70 component Bl) ln the kneader and subjecting the resulting mixture to dry preliminary kneading at pH 7 to ll to a residual moisture content of 3 to 12% by weight before component B2 is added.
Desirably the catalyst is obtained by precalcining the dry-prekneaded mixture of components A) and Bl) at temperatures of 400 to 700C before component B2) is added. Suitably the catalyst is obtained by precalcining the paste consisting of components A), B1) and B2) at 300 to ~00C before it is kneaded to a homogeneous kneaded paste.
In a further embodiment of the present invention the u catalyst is obtalned by components Bl) and B2) which are used in the form of a heteropoly acid or one of its salts the metals of groups Bl) and B2) present in the heteropoly acid being present in an atomic ratio of 12 : l to l : 12.
l!;
In a still further embodiment of the present invention the salt is the ammonium salt.
In addition, the new catalyst production process, by 2U saving several proces steps, guarantees more direct and, at the same time, more flexlble control of the catalyst 2~
- 6a -~ 139'~'~
prop~rties. Thus, t~le resistance of the catalysts to sintering can be improved by the choice of a suitable stabilizer component from group Bl). This is re~lected in the fact that the high BET surface of the final catalyst remains substantially constant under in-use conditions and in the fact that the temperature-induced phase transition of the titanium dioxide from the anatase to the rutile modification is suppressed. ~i~t-~etl~ -lo~ger--use~ul--~-~e~
~f tho ~ l}cte~ebt-~nablc in accordance with thc cl~
are the dire~t rcsult of thcGc--pro~crtic_.
Figure 1 (for Example 13) illustrates the reduction in activity fall-off during long-term use in flue gases of dry cjofal-burning plants with operating temperatures above 300~C
~crc sio2 is used as stabilizer in the catalyst.
Through the physicochemical properties of the startin~
materials ~Tio2 anatase, stabilizers from group Bl), acti-vators from group B2) and through the choice of the other additives and through processing in a kneader in accordance with the invention, the pore volume and pore radiu3 dis~
tribution of a given kneaded paste can be controlled by empirical variation of its moisture content during the size kneading proc~ss. The pore radiur~ distribution can be varied within wide limits over the mesopore and macropore range, mono- bi- and trimodal pore ra~ZuG distributions and transitional forms in between being adjustable as required.
The correct choice of these parameters leads to a consid-era~le increase in the activity of the catalyst. However, poreVdistribution and pore volume also have a major influ-ence.on resi~an~e to poisoning and hence directly on the statlonary ~ltetlme uroful~ 4-of the catalysts.
In this connection, particular significance is also attributed to the pK value of the solid surface. In the catalyst according to the invention, the pK value may be varied within wide limits through the choice of the stabil-izers or activators. The use of heteropoly acids as *) As a d;rect result of these propert;es catalysts obta;nable ;n accordance with the cla;ms have dist;nctly longer stationary lifetimes~
;~:q~3 ~9'~'~
activators and/or st~bilizers is particular]y mentioned in this re~ard. Interestingly, it has been found that, when used i31 the particularly problematical flue gases of coal-fired sl~g-tap furnaces, catalyst~ made of these materials show a distinctly lower tendency to ~u~-~ arsenic and other catalyst poisons by comparison, for example, with the catalysts according to DE-PS 25 58 888. This is attri-butable to increased poisoning resistance through reduced heavy metal adsorption to the catalyst surface. As a result, catalysts can be used over industrially useful periods in the high-dust operation of coal-fired slag-tap fur~ces. By contrast, known comparison catalysts are rapidly deactivated mainly by heavy metals present in the flue gas.
Figures 2 and 3 show the surprisingly high increase in activity of catalysts according to the invention by com-parison with a catalyst conventionally produced in accord-ance with Comparison Example l.
The invention is further illustrated by the following Examples.
The catalysts were tested both in dust-free model exhaust gases in a laboratory test plant and also in the exhaust gas of an oil-burning plant. In addition, long-term tests were carried out in the flue gas of a dry coal-burning plant.
The catalyst tests were carried out at temperatures in the range from 200 to 500C. The space velocities were between 10,000 and 40,000 h-1. The reducing agent, ammonia, and the nitrogen oxide were used in the particular molar ratio found to bc fa~ h~ of 0.~ to 1.6t~ preferably 0.8 to 1.2t which was found to be favourable.
Comparison Example 20 Litres deionized water, 6 kg 15% by weight aqueous NH3 solution, 1.8 kg monoethanolamine and a solution of 2~
ammollium m~t~lv~nadate corresponding t~ 3~0 g V2o5 were added to 35 k~ of an intimate mixture of the oxides Tio2 and W03 in a r~tio by weight of 9 : 1 prepared in accordance with DE-PS 24 5~ 8~8. The mixture is intensively kneaded with a varying moisture conten-t a~d at temperatures of 70 to 90C. 620 g Sio2, 1.4 kg alkali-free clay and 3.5 kg glass fibres (length 1 to 8 mm) were then successively added.
The mixture is kneaded for 6 to 8 hours to form a homogene-ous kneaded paste, 410 g polyethylene oxide, 410 g carboxy-lo methyl cellulose, 230 g lactic acid and 11~5 kg fully deionized water additionally being added to establish the plasticity required for subsequent shaping.
The catalyst paste is then extruded in an extruder to honeycomb monoliths with passages of square cross-section (cell division: 3.4 mm or 7.4 mm).
The extrudates are dried at an increasing temperature of 20 to 60~C in an air-conditioned drying chamber and, after a stepwise increase in temperature, are finally calcined for 24 hours at 620C.
Examples 1 to 9 The composition of the catalysts is shown in Table 1.
The following basic procedure was adopted to prepare the catalysts:
4.4 kg ammonium paratungstate (APW), 22 litres deion-ized water, 7.5 kg 15% by weight aqueous NH3 solution, 1.8 kg monoethanolamine and a solution of ammonium metavanadate corresponding to 390 g VzOs are added to 35 kg of the Tio2 anatase mentioned in claim 1 with a BET surface of 98 m2/g.
670 g sio2, 2.5 kg glass fibres ~length 1 to 8 m~) and 1.5 kg alkali-free clay are then successively added with inten-sive kneading at a temperature in the range from 60 to 90C. The mixture is kneaded for 5 to 7 hours to form a homogeneous kneaded paste (Werner & Pfleiderer LUK 2.5 kneader), 450 g polyethylene oxide, 450 g carboxymethyl 20~037~
cellulose, 250 g lactic acid and 12.3 litres deionized water being additionally incorporated to establish the necessary plasticity. To fine-tune the moisture content and the plasticity of the kneaded paste, more ammonia water had to be added before the end of the kneading process.
The catalyst paste is then extruded in an extruder to honeycomb monoliths with passages of square cross-section (cell division: 3.4 mm). After drying at an increasing temperature of 20 to 60~C in an air-conditioned drying lo chamber, followed by a stepwise increase in temperature, the mouldings are calcined for 24 hours at 620-C.
In Examples 6 to 9, Tio2-P-25 produced by flame-hydrolysis (Degussa), tungsten oxide or boron oxide and Nb205, the latter in the form of niobium oxalate dissolved in water, were respectively used instead of Tio2 anatase, ammonium paratungstate (APW) and ammonium metavanadate (AMV).
_~ ___ 2 ~ ql .
~C X
p~N
0~
O ~ O O O ~ O O O O U~
'~ ri ~ O
R.~;~
p~X
____ _ _____ _. . __ ~ U~
O ~ N
~a) ~ X ,~ o o ~ o 0~
O u~
o~
_ __ _ __ _ m~
~ ~ ~ :3 3 ~ 0~ 0~ o~
u ~ m _ ._ ._ a u~
P~
3 ~ 3 ~ 3 3 .
N X ,1 ~ ~ ~ ~) ~D 1~ 0~ a~
E~
~3~
Examples 10 to 13 ~.4 kg ammonium paratungstate (APW) and 10 kg 15% by weight aqueolls N~l3 solution are added to 35 kg of the Ti anatase mentioned in claim 1, BET surface 75 m2/g, in a kneader which has been switched on. The suspension obtain-ed is kneaded for 3 hours at 80C to dryness (residual moisture 5 to 10~ by weight). 22 Lltres deionized water, 75 kg 15% by weight aqueous NH3 solution, 1.8 kg monoethan-olamine and a solution of ammonium metaYanadate (AMV) cor-responding to 390 g V2Os are then added to the mixture thus obtained. The resulting paste is further processed as described in Examples 1 to 9 and extruded to form the same honeycomb monoliths. Th ~ monoliths are also dried and calcined by the method described in Examples 1 to 9.
In Example 11, the ammonium metavanadate was replaced by ammonium molybdate (AM) and, in Examples 12 and 13, the ammonium paratungstate was replaced by BaO or sioz, as shown in Table 2.
__-_ _ ____ ~ 7~3 OXN~ -~ ~ o o o c~
~o ,i ~
~ X
~ m^' ~ '' '' R ~ .. .. .. ..
~ O u~
~; ~ a~
m- _ ~ ~ ~ O O
u ~
u~
U ~
a O
, (3~'-3'~
Exam~lP _ 1~ to 17 4.0 kg aluminium oxide and 12.5 kg 50% by weight aqueous Nll3 solution are added to 3S kg of the Tioz anatase mentioned in claim 1 with BET surface of 40 m2/g. The paste is kneaded for 2 to 3 hours at 80C to a residual moisture content of 5 to 10~ by weight. The powder is then precal-cined for ~ hours at 400C.
22 Litres deionized water, 75 kg ~4% by weight aqueous NH3 solution, 2 . O kg monoethanolamine, 210 g pulp (coarse-fibre cellulose~ and then a solution of ammonium metavana-date corresponding to 390 g V2O5 are added to the precal-cined oxide mixture in the kneader. 2.3 kg alkali-free clay, 2.2 kg glass fibres (length 1 to 8 mm), 200 g poly-ethylene oxidde~jt200 ~lcarboxymethyl cellulose and 250 y lactic acid are ~he~ added with intensive kneading at 60 to 90C. The mixture is kneaded for 5 to 7 hours to form a homogeneous kneaded paste, more ammonia water being added to establish the necessary plasticity. Finally, the cata-lyst paste is extruded in an extruder to honeycombs having square passages (cell division: 7.4 mm). After drying at an increasing temperature (20 to 60C) in an air-condi-tioned drying chamber, followed by a stepwise increase in temperature, the mouldings are calcined for 24 hours at 700C.
In Examples 15 to 17, the aluminium oxide was replaced by ammonium paratungstate or lanthanum oxide and, in Example 16, the ammonium metavanadate was replaced by copper(II) acetate dissolved in water, as shown in Table 3.
a ~ 2Q3 5~97'~3 o o ul o r~ O
~-X N
a~
U~ - __ æ~"~ ,1 ,1 o o ~ o ~ ~
. ._ m U N ~ ~ N
__ _ _ __ __ Ul U~
~ @ ~ i I r~ r 3~ 3 Exam~les 18 to 21 4.0 kg zirconiun- oxide, 390 g V2O5 and 15 kg 15% by weight aqueous Nl13 solution are added to 35 kg of the Tio2 anatase mentioned in claim 1 with a BET surface of 280 m2/g.
The thinly liquid paste i5 kneaded for 2 to 4 hours at 80C
to a residual moisture content of 5 to 10% by weight. The dry powder is then precalcined for 2 hours at 700C.
25 kg ~*~ deionized water, 75 kg 15% by weight NH3 solution and 2.0 kg monoethanolamine are added to the pre-calcined mixture, followed by further processing as in Examples 1 to 9. The final catalyst paste is extruded to honeycombs as in Examples 14 to 17.
In Examples 19 to 21, zirconium dioxide was replaced by ammonium paratungstate or phosphorus pentoxide and, in Example 20, V205 was replaced by iron(III) oxide, as shown in Table 4.
'x x ~ J ~
m^
m ~ ~ o o o o p, ~ x m~
U N 9 ~ ..
~Q~
~-x ~
.. .. .. ..
x O a) o~
U 0 ~5: 3 0 a) o o o .
~ ~ ~) ~ ~
~1 -' N¦ ~ O ~
Exam~les 22 to 26 422 g ammonium-2-hydrogen-12-vanadophosphate and 2~
litres deionized water are added to 35 kg of the Tio2 anatase mentioned in claim 1 with a BET surface of 98 mZ/g.
The paste is intensively kneaded at temperatures of 40 to 70OC, 670 g Sio2, 2.S kg glass fibres (length 1 to 8 mm) and 6.0 kg alkali-free clay being additionally introducPd.
In addition, 450 g polyethylene oxide, 900 g carboxymethyl cellulose, 250 g lactic acid and 15 litres deionized water are added to establish the necessary plasticity.
The. mixture is kneaded for 5 to 7 hours to a homogene-ous kneaded paste which is then processed as in Examples 1 to 9 to honeycomb monoliths.
In Examples 23 to 26, the ammonium-2-hydroxy-12-vanadophosphate was replaced by heteropoly acids, as shown in Table 5:
Table 5 __ ~
Example Comp. A Comp. Bl + B2 Ratio by weight A oxide/B2 oxide __ _ _ 22 Anatase (NH4)sH2[P(vl2o36] 9.99 : 0.01 23 Anatase (NH4)s[V6w6037] 9.9 : 0.1 24 Anatase H4[P(Mllv04o)] 9.99 : 0.01 Anatase H6~P(MogV3040)J 9.99 : 0.01 26 Anatase (NH4~6H~P(Mollcuo4o)] 9.99 : 0.01 . ~
Examples 27 to 31 4.3 kg ammonium paratungstate, 22 litres deionized water, 7.5 ky 15% hy weight aqueous NH3 solution and 1.8 kg monoethanolamine are added to 35 kg of the Tio2 anatase )9 ~ ~
mentionecl in Example 1 Wit}l a BET surface of 9~ m2/g. As in Examples 1 to 9, tlle paste is provided with additives ~plasticizers, supporting materials, etc.), intensively kneaded (2 to 7 hours at 60 to 90OC) and extruded to holleycomb monoliths which, in this case, count as catalyst precursors. The monoliths are dried and calcined as in Examples 1 to 9 and, after cooling ~ , 1.0 g vanadium pentoxide per 100 g titanium dioxide/tungsten oxide mixture is applied by impregnation with a solution of ammonium-2-hydrogen~12-vanadophosphate in a quantity of water corrdes~o~din~ to the water absorption capacity of the ~as mentlone 1 c alm honeycomb monolith~. The monoliths are dried at 150-C w~1~o 9 air ~Lows_~c~g~ and are subsequently conditioned for 2 hours at 400'C.
In Examples 28 to 31, the ammonium paratungstate and ammonium-2-hydrogen-12-vanadophosphate are respectively replaced by the quantities shown in Table 6 of ammonium metatungstate, yttrium oxide, zirconium dioxide or silicon dioxide and V2O5 (in the form of aqueous solutions of vanadium oxalate), ammonium-6-tungstato-6-vanadate or 11-molybdo-l-vanadophosphoric acid.
_ lq _ ~xx o ,~ ~ R ~
0~
ooooo ~
._ .
P~ ~ 0~
O ~u~
~ X N
. O ~ o ~
~ .. .. .. .. .
O ~,1 a:
~ X ~
P~ ~
m- _ '¢ ~ N h ~1 .) :~ N Ul ~ .. _ C~ 0 0 ,~ 0 ~
, ~ r~ o Q ~
~Z~3~Q9~
Testin~ of the c~talysts roduced The catalysts prepared in accordance with Examples 1 to 31 were tested in the exhaust gas of an oil-burning plant WhiC}l was adjusted to meet the following test condi-tions by the introduction of additional pollutants (NO~ and SO2) and ammonia required for nitrogen oxide reduction.
Test conditions:
Exhaust gas composition: N0~ 800 ppm NH3 800 ppm S02 500 ppm 2 5.0 % by vol.
HzO 11.0 % by vol.
C02 12.0 % by vol.
N2 balance The catalyst tests were carried out at a temperature in the range from 250 to 500C and at a space velocity of 20,000 hl~ Selected results of the measurements and long-term tests in dry coal-burning plants under the conditions already described are shown in the form of graphs in Figures 1, 2 and 3. The basic measured data are shown in Tables 7 and 8.
-----~
. ~ ~o o tn t~ o t~
~i ~X ~ U) ~D 1~ CO OD 1 t~ c~ 0 ~ ~ ~ ~ ~ ~ ~r oo ~ co ~a - -- ----I
I~ O ~
~ ~ co -- - -- -- - ------ u ~ n o ,~ ~ o ~ ,i co ---- - -- o~
o In ~ In ~ In ~ ~ ~ ,1 ~ 1~
- ---- ~l ~ ~ O U) S~ .
~1 OOt~ ~I N 00 a~ ~
~ m ~ oo co co __ _ UX
o u~ In ~ ~ ~ ~ z;
~1 a~ 0 m ~ c~ co I co . _ _ S~
~ oo ,i r~ D ~ .
O ~ ~ O ~ ~D
co ~: ~
_~ O o ~1 o,1 1` o ~ r~ ~:r S
~o ~ In ~ ~ ~r o ~
1::
'`¦ 1~ / o o o o o c, O _ ~D oX
~X / E~ m a~ r~l w o m o E~ Z
Q ~/ ~ ~ f~ r In E~ ~ *
;~Q~3976~
Table_~*
. . . _ . _ _ Dry coal-burning plant (T=450C) t[}l~ Examples Comparison 1 6 13 Example .. .. ._ ._ . ..
Zero measurement 95 92 89 83 500 gl.5 86 84.5 75.5 1000 89.5 ~5 84 73.5 2000 88 85 83.5 73 3000 88 84.5 83.5 72.5 4000 87.5 84.5 83.5 71.5 . _ _ values * The figure~ shown represent NOX conversions (~NO ) in percent, based on the starting NOX concentration ~3
~-1 iron and vanadium in the form of oxides and/or from the group s-2 molybdenum, tungsten, nickel, cobalt, copper, chromium and uranium in the form of oxides C) tin in the form of oxides D) metals from the group consisting of beryllium, magnesium, zinc, boron, aluminium, yttrium, rare earth elements, silicon, niobium, antimony, bis-lo muth and manganese in the form of oxides.
The components are present in atomic ratios of A : B ~ C :
D of 1 : 0.01 to 10 : 0 to 0.2 0 to 0.15 nltrogen oxlde A catalyst having this composition is used for the-reduction ~ gas mixtures containing oxygen and ammonia at temperatures in the range from 150 to 550C and at space velocities of 300 to 100,000 h-1.
These catalysts may be produced by measures known per se. However, these measures must always guarantee that the components A) and B) and, optionally, C) can be obtained as an intimate mixture in the form of their oxides. The fol-lowing are mentioned as typical examples o~ such production processes:
la: homogeneous dissolving process lb: co-precipitation processes 2 : cGmbinations of the dissolving and precipitation processes 3 : mixed precipitate processes.
Solutions and/or precipitates, such as for example hydroxides or aqueous gels, are used as precursors of components A), B) and C), being intimately mixed and then subjected to calcination. The precursors are pyrolized, giving the desired intimate mixture of the oxides of the components critical to the catalysis process. The calcin-ation temperature has to be in the range from 300 to 800~C.
Below 300C, it is not possible to obtain an intimate 97~
mixture of the oxides and therefore no active catalyst;
above 800 C, sinterilly occurs and results in loss of the acti~e catalyst surface.
Ille starting mate~ials used for titanium as component A) include, for example, various titanium acids, titanium hydroxide and various titanium salts, such as halides, titanium sulfate, titanyl sulfate and the like. Organic compounds of titanium, for example titanium alkoxides, may also be used as starting material for the titanium. Titan-ium oxide in the calcined rutile or anatase form is not suitable.
The catalyst material described in DE-PS 35 31 809 is based on a further development of these catalyst production processes described in DE-AS 24 58 888. Titanium dioxide is used as starting material for the production of this catalyst material and is ground together with vanadium oxide and one or more oxides of the elements tungsten, molybdenum, phosphorus, chromium, copper, iron, uranium and then ~ bc~ed to at least one heat treatment. In ~his le~-$æea$~e~t, the tungsten and molybdPnum are completely or partly replaced by phosphorus in the form of its oxides or phosphates. The mills used are preferably eccentric disc mills and ring chamber mills. The calcination step takes place at a temperature in the range from 200 to 900C.
With all hitherto known catalysts of this type, com-ponents A) and B) (for example A = Ti; B = W, Mo. etc.) must be present in the form of an intimate mixture of their oxides. This mixture is then subjected to a shaping pro-cess from which the catalysts can be obtained in the form of loose material or honeycomb monoliths by compre5sion moulding or extrusion.
This means that shaping of the catalyst, for example by extrusion, has to be preceded by a process of which the object is to form the intimate mixture as starting materi-20~0970 al. Thls procedure, which is widely used at the present time, is attended by the followlng disadvantages:
- elaborate, multlstage, energy-intenslve process steps are necessary - the productlon of the lntlmate mixture ln accordance with DE-AS 24 58 888 is not environment-friendly on account of emission and wastewater problems;
- the operatlon of mills for grIndlng activatlon is energy-o lntenslve and requlres elaborate noise control measures and dust control systems;
- the preliminary process steps for formlng the lntlmate ~mixture are a serious cost factor in the production of the catalyst.
Accordingly the present invention greatly simplifies and, hence, dlstlnctly reduces the cost of catalyst productlon by 2U saving process steps in the productlon of so-called solld type catalysts~whlch conslst throughout of catalytically active materlal) for the selectlve reduction of nltrogen oxides in oxygen-containing exhaust gases in the presence of ammonia. In addltlon, the inventlon enables the~propertles~of the catalyst to be dlrectly and finely controlled through the management of the process.
~:
According to the present inventlon there ls provlded a catalyst for the selective reductlon of nitrogen oxides with ammonia contalning the followlng components: A) titanium oxide, 3U Bl) at least one oxide of tungsten,~sillcon, boron, aluminum, phosphorus, zirconium, barium, yttrium, lanthanum, cerium, and B2) at least one oxide of vanadium, nlobium, molybdenum, iron copper, wlth an atomlc ratlo between the elements of components A) and B) of 1 : 0.001 to 1 obtalned by lntenslvely kneadlng ~ 109~0 component A) in the form of a reactive high-surface titanlum oxide having a BET surface of 40 to 500 m2/g, whlch is completely or predomlnantly present ln the anatase modlfication, together wlth components sl) and s2) or thelr precursors, wlth the addition o of the additlves normally used for the compresslon moulding or extrusion of ceramlc pastes, moistening agents, supporting substances, blnders, mouldlng aids and. to form a homogeneous kneaded paste, extruding the kneaded paste to mouldings, drying the mouldlngs with a gradual increase in temperature to at most 60C and then calcinlng them with a stepwise lncrease in temperature in ambient air at:flnal lU temperatures ln the range from 300 to 800C. Suitably 2. A
catalyst is obtalned by using hydroxides, oxides, salts or heteropoly acids or salts thereof as starting material for components sl) and B2).
l!;
Thus according to the present invention certain titanium oxide materials are processed by kneading and there is.
no longer any need for the already known measures for the formation of on intimate oxlde mlxture.
Suitable titanium oxides are reactive high-surface titanium oxldes having a specific BET surface of from 40 to 500 preferably 50 to 300 and more preferably 75 to 150 m2/g whlch are completely or predominantly present:in anatase form, These 2r materials may be commercial products produced by precipation or ~ by flame hydrolysis. Apart 3U .
.
- - 4a -2~ 3~"3 ~ ~3 from tll~ir higll specific surface, these generally highly disperse products have a very narrow particle siz~ distri-bution witll an averaye primary particle size of the order of 30 ~m.
The individual elements of group B) may be used, for example, in the form of the following starting compounds:
tungsten oxide, ammonium para- or meta-tungstate, silicon dioxide, silicotungstic acid, silica, boron oxide, boric acid, aluminium oxide, phosphorus oxide, ammonium phos-phate, phosphotungstic acid, phosphomolybdic acid, zir-conium dioxide, zirconium phosphate, barium oxide, yttrium oxide, lanthanum oxide, cerium acetate, cerium nitrate, cerium oxide, borotungstic acid, vanadium oxide, vanadyl oxalate, ammonium metavanadate, vanadotungstic acids, vanadomolyhdic acids, vanadophosphomolybdic acids, phospho-vanadic acid, niobium oxide hydrate, niobium oxalate, niobium vanadic acids, ammonium molybdate, molybdenum oxide, iron oxide, iron phosphate, iron hydroxide, organic iron salts, such as iron oxalate, copper acetate, copper-(II) oxide, Cu-, Ce-, La-containing heteropoly acids, etc.
The substances mentioned may be used in the form of solutions or even in the form of solid substances.
Apart from the actual catalyst material, a number of additives known ~er se are required for the production of solld type the whol~ catalysts according to the invention.
Deionized water, aqueous ammonia solution, monoethan-olamine and alcohols may be used as the moistening agent.
Glass fibers of various sizes, for example, may be used as supporting materials.
Suitable binders, which provide the paste to be pro-duced with sufficient stability in the so-called green state after shaping, are cellulose derivatives such as, for example, carboxymethyl cellulose or even unsubstituted celluloses.
Polyethylene, polypropylene, polyvinyl alcoholl poly-~ 3 ethylene oxide, polyacrylamide or polystyrene may also be used as the binder.
To facilitate compression moulding or to improve extrudabillty, mouldlng aids and/or lubricants such as, for example, bentonites, aluminas, organlc acids, paraffin, waxes, ; silicone oils, are added.
Finally, the porosity (pore volume, pore size distribution) of the whole catalyst may be ad~usted as required by the addition of suitable air-~ntraining agents. ~dditives Lu such as these are, for example, finely divided carbons or wood pulp, which burn out at the calcination temperatures applied.
Kneading units are used for intensively kneading the starting materials to a homogeneous kneaded paste. Kneaders with 1~ sigma or masticator blades are preferred. The use of a certain titanium oxide in accordance with the invention in conjunction with an intensive kneading step for preparing the catalyst paste affords considerable advantages over the conventional production 2U process. Thus, there is no longer any need for elaborate environment polluting and, hence, expensive process steps. Co-precipitation and grinding processes for preparing an intimate oxids mixture are no longer necessary. This leads to a distinct reduction in production costs and also eliminates dependence on expensively produced starting materials.
2~
In addition, contraction, a key parameter in regard to the tendency of solid type catalysts to crack and in regard to their breaking strength, can be regulated as required by the use of suitable starting materials and by adaption of the kneading 3~ process in regard to intensity, temperature and time, including intermediate conditioning steps.
Thus according to one embodiment of the present invention the catalyst is obtained by mixing component A) and 3~
;~311Uf~70 component Bl) ln the kneader and subjecting the resulting mixture to dry preliminary kneading at pH 7 to ll to a residual moisture content of 3 to 12% by weight before component B2 is added.
Desirably the catalyst is obtained by precalcining the dry-prekneaded mixture of components A) and Bl) at temperatures of 400 to 700C before component B2) is added. Suitably the catalyst is obtained by precalcining the paste consisting of components A), B1) and B2) at 300 to ~00C before it is kneaded to a homogeneous kneaded paste.
In a further embodiment of the present invention the u catalyst is obtalned by components Bl) and B2) which are used in the form of a heteropoly acid or one of its salts the metals of groups Bl) and B2) present in the heteropoly acid being present in an atomic ratio of 12 : l to l : 12.
l!;
In a still further embodiment of the present invention the salt is the ammonium salt.
In addition, the new catalyst production process, by 2U saving several proces steps, guarantees more direct and, at the same time, more flexlble control of the catalyst 2~
- 6a -~ 139'~'~
prop~rties. Thus, t~le resistance of the catalysts to sintering can be improved by the choice of a suitable stabilizer component from group Bl). This is re~lected in the fact that the high BET surface of the final catalyst remains substantially constant under in-use conditions and in the fact that the temperature-induced phase transition of the titanium dioxide from the anatase to the rutile modification is suppressed. ~i~t-~etl~ -lo~ger--use~ul--~-~e~
~f tho ~ l}cte~ebt-~nablc in accordance with thc cl~
are the dire~t rcsult of thcGc--pro~crtic_.
Figure 1 (for Example 13) illustrates the reduction in activity fall-off during long-term use in flue gases of dry cjofal-burning plants with operating temperatures above 300~C
~crc sio2 is used as stabilizer in the catalyst.
Through the physicochemical properties of the startin~
materials ~Tio2 anatase, stabilizers from group Bl), acti-vators from group B2) and through the choice of the other additives and through processing in a kneader in accordance with the invention, the pore volume and pore radiu3 dis~
tribution of a given kneaded paste can be controlled by empirical variation of its moisture content during the size kneading proc~ss. The pore radiur~ distribution can be varied within wide limits over the mesopore and macropore range, mono- bi- and trimodal pore ra~ZuG distributions and transitional forms in between being adjustable as required.
The correct choice of these parameters leads to a consid-era~le increase in the activity of the catalyst. However, poreVdistribution and pore volume also have a major influ-ence.on resi~an~e to poisoning and hence directly on the statlonary ~ltetlme uroful~ 4-of the catalysts.
In this connection, particular significance is also attributed to the pK value of the solid surface. In the catalyst according to the invention, the pK value may be varied within wide limits through the choice of the stabil-izers or activators. The use of heteropoly acids as *) As a d;rect result of these propert;es catalysts obta;nable ;n accordance with the cla;ms have dist;nctly longer stationary lifetimes~
;~:q~3 ~9'~'~
activators and/or st~bilizers is particular]y mentioned in this re~ard. Interestingly, it has been found that, when used i31 the particularly problematical flue gases of coal-fired sl~g-tap furnaces, catalyst~ made of these materials show a distinctly lower tendency to ~u~-~ arsenic and other catalyst poisons by comparison, for example, with the catalysts according to DE-PS 25 58 888. This is attri-butable to increased poisoning resistance through reduced heavy metal adsorption to the catalyst surface. As a result, catalysts can be used over industrially useful periods in the high-dust operation of coal-fired slag-tap fur~ces. By contrast, known comparison catalysts are rapidly deactivated mainly by heavy metals present in the flue gas.
Figures 2 and 3 show the surprisingly high increase in activity of catalysts according to the invention by com-parison with a catalyst conventionally produced in accord-ance with Comparison Example l.
The invention is further illustrated by the following Examples.
The catalysts were tested both in dust-free model exhaust gases in a laboratory test plant and also in the exhaust gas of an oil-burning plant. In addition, long-term tests were carried out in the flue gas of a dry coal-burning plant.
The catalyst tests were carried out at temperatures in the range from 200 to 500C. The space velocities were between 10,000 and 40,000 h-1. The reducing agent, ammonia, and the nitrogen oxide were used in the particular molar ratio found to bc fa~ h~ of 0.~ to 1.6t~ preferably 0.8 to 1.2t which was found to be favourable.
Comparison Example 20 Litres deionized water, 6 kg 15% by weight aqueous NH3 solution, 1.8 kg monoethanolamine and a solution of 2~
ammollium m~t~lv~nadate corresponding t~ 3~0 g V2o5 were added to 35 k~ of an intimate mixture of the oxides Tio2 and W03 in a r~tio by weight of 9 : 1 prepared in accordance with DE-PS 24 5~ 8~8. The mixture is intensively kneaded with a varying moisture conten-t a~d at temperatures of 70 to 90C. 620 g Sio2, 1.4 kg alkali-free clay and 3.5 kg glass fibres (length 1 to 8 mm) were then successively added.
The mixture is kneaded for 6 to 8 hours to form a homogene-ous kneaded paste, 410 g polyethylene oxide, 410 g carboxy-lo methyl cellulose, 230 g lactic acid and 11~5 kg fully deionized water additionally being added to establish the plasticity required for subsequent shaping.
The catalyst paste is then extruded in an extruder to honeycomb monoliths with passages of square cross-section (cell division: 3.4 mm or 7.4 mm).
The extrudates are dried at an increasing temperature of 20 to 60~C in an air-conditioned drying chamber and, after a stepwise increase in temperature, are finally calcined for 24 hours at 620C.
Examples 1 to 9 The composition of the catalysts is shown in Table 1.
The following basic procedure was adopted to prepare the catalysts:
4.4 kg ammonium paratungstate (APW), 22 litres deion-ized water, 7.5 kg 15% by weight aqueous NH3 solution, 1.8 kg monoethanolamine and a solution of ammonium metavanadate corresponding to 390 g VzOs are added to 35 kg of the Tio2 anatase mentioned in claim 1 with a BET surface of 98 m2/g.
670 g sio2, 2.5 kg glass fibres ~length 1 to 8 m~) and 1.5 kg alkali-free clay are then successively added with inten-sive kneading at a temperature in the range from 60 to 90C. The mixture is kneaded for 5 to 7 hours to form a homogeneous kneaded paste (Werner & Pfleiderer LUK 2.5 kneader), 450 g polyethylene oxide, 450 g carboxymethyl 20~037~
cellulose, 250 g lactic acid and 12.3 litres deionized water being additionally incorporated to establish the necessary plasticity. To fine-tune the moisture content and the plasticity of the kneaded paste, more ammonia water had to be added before the end of the kneading process.
The catalyst paste is then extruded in an extruder to honeycomb monoliths with passages of square cross-section (cell division: 3.4 mm). After drying at an increasing temperature of 20 to 60~C in an air-conditioned drying lo chamber, followed by a stepwise increase in temperature, the mouldings are calcined for 24 hours at 620-C.
In Examples 6 to 9, Tio2-P-25 produced by flame-hydrolysis (Degussa), tungsten oxide or boron oxide and Nb205, the latter in the form of niobium oxalate dissolved in water, were respectively used instead of Tio2 anatase, ammonium paratungstate (APW) and ammonium metavanadate (AMV).
_~ ___ 2 ~ ql .
~C X
p~N
0~
O ~ O O O ~ O O O O U~
'~ ri ~ O
R.~;~
p~X
____ _ _____ _. . __ ~ U~
O ~ N
~a) ~ X ,~ o o ~ o 0~
O u~
o~
_ __ _ __ _ m~
~ ~ ~ :3 3 ~ 0~ 0~ o~
u ~ m _ ._ ._ a u~
P~
3 ~ 3 ~ 3 3 .
N X ,1 ~ ~ ~ ~) ~D 1~ 0~ a~
E~
~3~
Examples 10 to 13 ~.4 kg ammonium paratungstate (APW) and 10 kg 15% by weight aqueolls N~l3 solution are added to 35 kg of the Ti anatase mentioned in claim 1, BET surface 75 m2/g, in a kneader which has been switched on. The suspension obtain-ed is kneaded for 3 hours at 80C to dryness (residual moisture 5 to 10~ by weight). 22 Lltres deionized water, 75 kg 15% by weight aqueous NH3 solution, 1.8 kg monoethan-olamine and a solution of ammonium metaYanadate (AMV) cor-responding to 390 g V2Os are then added to the mixture thus obtained. The resulting paste is further processed as described in Examples 1 to 9 and extruded to form the same honeycomb monoliths. Th ~ monoliths are also dried and calcined by the method described in Examples 1 to 9.
In Example 11, the ammonium metavanadate was replaced by ammonium molybdate (AM) and, in Examples 12 and 13, the ammonium paratungstate was replaced by BaO or sioz, as shown in Table 2.
__-_ _ ____ ~ 7~3 OXN~ -~ ~ o o o c~
~o ,i ~
~ X
~ m^' ~ '' '' R ~ .. .. .. ..
~ O u~
~; ~ a~
m- _ ~ ~ ~ O O
u ~
u~
U ~
a O
, (3~'-3'~
Exam~lP _ 1~ to 17 4.0 kg aluminium oxide and 12.5 kg 50% by weight aqueous Nll3 solution are added to 3S kg of the Tioz anatase mentioned in claim 1 with BET surface of 40 m2/g. The paste is kneaded for 2 to 3 hours at 80C to a residual moisture content of 5 to 10~ by weight. The powder is then precal-cined for ~ hours at 400C.
22 Litres deionized water, 75 kg ~4% by weight aqueous NH3 solution, 2 . O kg monoethanolamine, 210 g pulp (coarse-fibre cellulose~ and then a solution of ammonium metavana-date corresponding to 390 g V2O5 are added to the precal-cined oxide mixture in the kneader. 2.3 kg alkali-free clay, 2.2 kg glass fibres (length 1 to 8 mm), 200 g poly-ethylene oxidde~jt200 ~lcarboxymethyl cellulose and 250 y lactic acid are ~he~ added with intensive kneading at 60 to 90C. The mixture is kneaded for 5 to 7 hours to form a homogeneous kneaded paste, more ammonia water being added to establish the necessary plasticity. Finally, the cata-lyst paste is extruded in an extruder to honeycombs having square passages (cell division: 7.4 mm). After drying at an increasing temperature (20 to 60C) in an air-condi-tioned drying chamber, followed by a stepwise increase in temperature, the mouldings are calcined for 24 hours at 700C.
In Examples 15 to 17, the aluminium oxide was replaced by ammonium paratungstate or lanthanum oxide and, in Example 16, the ammonium metavanadate was replaced by copper(II) acetate dissolved in water, as shown in Table 3.
a ~ 2Q3 5~97'~3 o o ul o r~ O
~-X N
a~
U~ - __ æ~"~ ,1 ,1 o o ~ o ~ ~
. ._ m U N ~ ~ N
__ _ _ __ __ Ul U~
~ @ ~ i I r~ r 3~ 3 Exam~les 18 to 21 4.0 kg zirconiun- oxide, 390 g V2O5 and 15 kg 15% by weight aqueous Nl13 solution are added to 35 kg of the Tio2 anatase mentioned in claim 1 with a BET surface of 280 m2/g.
The thinly liquid paste i5 kneaded for 2 to 4 hours at 80C
to a residual moisture content of 5 to 10% by weight. The dry powder is then precalcined for 2 hours at 700C.
25 kg ~*~ deionized water, 75 kg 15% by weight NH3 solution and 2.0 kg monoethanolamine are added to the pre-calcined mixture, followed by further processing as in Examples 1 to 9. The final catalyst paste is extruded to honeycombs as in Examples 14 to 17.
In Examples 19 to 21, zirconium dioxide was replaced by ammonium paratungstate or phosphorus pentoxide and, in Example 20, V205 was replaced by iron(III) oxide, as shown in Table 4.
'x x ~ J ~
m^
m ~ ~ o o o o p, ~ x m~
U N 9 ~ ..
~Q~
~-x ~
.. .. .. ..
x O a) o~
U 0 ~5: 3 0 a) o o o .
~ ~ ~) ~ ~
~1 -' N¦ ~ O ~
Exam~les 22 to 26 422 g ammonium-2-hydrogen-12-vanadophosphate and 2~
litres deionized water are added to 35 kg of the Tio2 anatase mentioned in claim 1 with a BET surface of 98 mZ/g.
The paste is intensively kneaded at temperatures of 40 to 70OC, 670 g Sio2, 2.S kg glass fibres (length 1 to 8 mm) and 6.0 kg alkali-free clay being additionally introducPd.
In addition, 450 g polyethylene oxide, 900 g carboxymethyl cellulose, 250 g lactic acid and 15 litres deionized water are added to establish the necessary plasticity.
The. mixture is kneaded for 5 to 7 hours to a homogene-ous kneaded paste which is then processed as in Examples 1 to 9 to honeycomb monoliths.
In Examples 23 to 26, the ammonium-2-hydroxy-12-vanadophosphate was replaced by heteropoly acids, as shown in Table 5:
Table 5 __ ~
Example Comp. A Comp. Bl + B2 Ratio by weight A oxide/B2 oxide __ _ _ 22 Anatase (NH4)sH2[P(vl2o36] 9.99 : 0.01 23 Anatase (NH4)s[V6w6037] 9.9 : 0.1 24 Anatase H4[P(Mllv04o)] 9.99 : 0.01 Anatase H6~P(MogV3040)J 9.99 : 0.01 26 Anatase (NH4~6H~P(Mollcuo4o)] 9.99 : 0.01 . ~
Examples 27 to 31 4.3 kg ammonium paratungstate, 22 litres deionized water, 7.5 ky 15% hy weight aqueous NH3 solution and 1.8 kg monoethanolamine are added to 35 kg of the Tio2 anatase )9 ~ ~
mentionecl in Example 1 Wit}l a BET surface of 9~ m2/g. As in Examples 1 to 9, tlle paste is provided with additives ~plasticizers, supporting materials, etc.), intensively kneaded (2 to 7 hours at 60 to 90OC) and extruded to holleycomb monoliths which, in this case, count as catalyst precursors. The monoliths are dried and calcined as in Examples 1 to 9 and, after cooling ~ , 1.0 g vanadium pentoxide per 100 g titanium dioxide/tungsten oxide mixture is applied by impregnation with a solution of ammonium-2-hydrogen~12-vanadophosphate in a quantity of water corrdes~o~din~ to the water absorption capacity of the ~as mentlone 1 c alm honeycomb monolith~. The monoliths are dried at 150-C w~1~o 9 air ~Lows_~c~g~ and are subsequently conditioned for 2 hours at 400'C.
In Examples 28 to 31, the ammonium paratungstate and ammonium-2-hydrogen-12-vanadophosphate are respectively replaced by the quantities shown in Table 6 of ammonium metatungstate, yttrium oxide, zirconium dioxide or silicon dioxide and V2O5 (in the form of aqueous solutions of vanadium oxalate), ammonium-6-tungstato-6-vanadate or 11-molybdo-l-vanadophosphoric acid.
_ lq _ ~xx o ,~ ~ R ~
0~
ooooo ~
._ .
P~ ~ 0~
O ~u~
~ X N
. O ~ o ~
~ .. .. .. .. .
O ~,1 a:
~ X ~
P~ ~
m- _ '¢ ~ N h ~1 .) :~ N Ul ~ .. _ C~ 0 0 ,~ 0 ~
, ~ r~ o Q ~
~Z~3~Q9~
Testin~ of the c~talysts roduced The catalysts prepared in accordance with Examples 1 to 31 were tested in the exhaust gas of an oil-burning plant WhiC}l was adjusted to meet the following test condi-tions by the introduction of additional pollutants (NO~ and SO2) and ammonia required for nitrogen oxide reduction.
Test conditions:
Exhaust gas composition: N0~ 800 ppm NH3 800 ppm S02 500 ppm 2 5.0 % by vol.
HzO 11.0 % by vol.
C02 12.0 % by vol.
N2 balance The catalyst tests were carried out at a temperature in the range from 250 to 500C and at a space velocity of 20,000 hl~ Selected results of the measurements and long-term tests in dry coal-burning plants under the conditions already described are shown in the form of graphs in Figures 1, 2 and 3. The basic measured data are shown in Tables 7 and 8.
-----~
. ~ ~o o tn t~ o t~
~i ~X ~ U) ~D 1~ CO OD 1 t~ c~ 0 ~ ~ ~ ~ ~ ~ ~r oo ~ co ~a - -- ----I
I~ O ~
~ ~ co -- - -- -- - ------ u ~ n o ,~ ~ o ~ ,i co ---- - -- o~
o In ~ In ~ In ~ ~ ~ ,1 ~ 1~
- ---- ~l ~ ~ O U) S~ .
~1 OOt~ ~I N 00 a~ ~
~ m ~ oo co co __ _ UX
o u~ In ~ ~ ~ ~ z;
~1 a~ 0 m ~ c~ co I co . _ _ S~
~ oo ,i r~ D ~ .
O ~ ~ O ~ ~D
co ~: ~
_~ O o ~1 o,1 1` o ~ r~ ~:r S
~o ~ In ~ ~ ~r o ~
1::
'`¦ 1~ / o o o o o c, O _ ~D oX
~X / E~ m a~ r~l w o m o E~ Z
Q ~/ ~ ~ f~ r In E~ ~ *
;~Q~3976~
Table_~*
. . . _ . _ _ Dry coal-burning plant (T=450C) t[}l~ Examples Comparison 1 6 13 Example .. .. ._ ._ . ..
Zero measurement 95 92 89 83 500 gl.5 86 84.5 75.5 1000 89.5 ~5 84 73.5 2000 88 85 83.5 73 3000 88 84.5 83.5 72.5 4000 87.5 84.5 83.5 71.5 . _ _ values * The figure~ shown represent NOX conversions (~NO ) in percent, based on the starting NOX concentration ~3
Claims (15)
1. A catalyst for the selective reduction of nitrogen oxides with ammonia containing the following components: A) titanium oxide, B1) at least one oxide of tungsten, silicon, boron, aluminum, phosphorus, zirconium, barium, yttrium, lanthanum, cerium, and B2) at least one oxide of vanadium, niobium, molybdenum, iron, copper, with an atomic ratio between the elements of components A) and B) of 1 : 0.001 to 1 obtained by intensively kneading component A) in the form of a reactive high-surface titanium oxide having a BET surface of 40 to 500 m2/g, which is completely or predominantly present in the anatase modification, together with components B1) and B2) or their precursors, with the addition of the additives normally used for the compression moulding or extrusion of ceramic pastes, moistening agents, supporting substances, binders, moulding aids and to form a homogeneous kneaded paste, extruding the kneaded paste to mouldings, drying the mouldings with a gradual increase in temperature to at most 60°C and then calcining them with a stepwise increase in temperature in ambient air at final temperatures in the range from 300 to 800°C.
2. A catalyst as claimed in claim 1, obtained by using hydroxides, oxides, salts or heteropoly acids or salts thereof as starting material for components B1) and B2).
3. A catalyst as claimed in claim 2 in which the starting material is the ammonia salt.
4. A catalyst as claimed in claim 1 obtained by mixing component A) and component B1) in the kneader and subjecting the resulting mixture to dry preliminary kneading at pH 7 to 11 to a residual moisture content of 3 to 12% by weight before component B2 is added.
5. A catalyst as claimed in claim 1 obtained by mixing component A) and component B1) in the kneader and subjecting the resulting mixture to dry preliminary kneading at pH 8 to 10 to a residual moisture content of s to 10% by weight before component B2 is added.
6. A catalyst as claimed in claim 4 or 5 obtained by precalcining the dry-prekneaded mixture of components A) and B1) at temperatures of 400 to 700°C before component B1) is added.
7. A catalyst as claimed in claim 1, 2, 3, 4 or 5 obtained by precalcining the paste consisting of components A), B1) and B2) at 300 to 800°C before it is kneaded to a homogeneous kneaded paste.
8. A catalyst as claimed in claim 1, 2, 3, 4 or 5 obtained by precalcining the paste consisting of components A), B1) and B2) at 400 to 700°C before it is kneaded to a homogeneous kneaded paste.
9. A catalyst as claimed in claim 1, in which components B1) and B2) are used in the form of a heteropoly acid or one of its salts the metals of groups B1) and B2) present in the heteropoly acid being present in an atomic ratio of 12 : 1 to 1 : 12.
10. A catalyst as claimed in claim 9 in which the salt is the ammonium salt.
11. A catalyst as claimed in claim 1, obtained by leaving the starting material for component B2) out of the kneading process and applying it by impregnation in the form of a salt or a heteropoly acid or one of its salts, in aqueous solution to the catalyst precursor consisting of components A) and B1).
12. A catalyst as claimed in claim 11, in which the catalyst precursor is calcined.
13. A catalyst as claimed in claim 1, 2, 3, 4 or 5 in which the titanium oxides have a BET surface of 50 to 300 m2/g.
14. A catalyst as claimed in claim 1, 2, 3, 4 or 5 in which the titanium oxides have a BET surface of 75 to 150 m2/g.
15. A catalyst as claimed in claim 1, 2, 3, 4 or 5 in which the kneaded paste also contains an air destroying agent.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEP3906136.1 | 1989-02-28 | ||
DE3906136A DE3906136C1 (en) | 1989-02-28 | 1989-02-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2010970A1 true CA2010970A1 (en) | 1990-08-31 |
Family
ID=6375060
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002010970A Abandoned CA2010970A1 (en) | 1989-02-28 | 1990-02-27 | Catalyst for the selective reduction of nitrogen oxides with ammonia |
Country Status (12)
Country | Link |
---|---|
EP (1) | EP0385164B1 (en) |
JP (1) | JPH02290250A (en) |
KR (1) | KR900012674A (en) |
AT (1) | ATE95443T1 (en) |
AU (1) | AU615375B2 (en) |
BR (1) | BR9000900A (en) |
CA (1) | CA2010970A1 (en) |
DD (1) | DD296854A5 (en) |
DE (2) | DE3906136C1 (en) |
DK (1) | DK0385164T3 (en) |
ES (1) | ES2046549T3 (en) |
RU (1) | RU2058814C1 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5120695A (en) * | 1989-07-28 | 1992-06-09 | Degusaa Aktiengesellschaft (Degussa Ag) | Catalyst for purifying exhaust gases from internal combustion engines and gas turbines operated at above the stoichiometric ratio |
US8863507B2 (en) | 2008-04-11 | 2014-10-21 | Umicore Ag & Co. Kg | Exhaust gas purification system for the treatment of engine exhaust gases by means of SCR catalyst |
US9242211B2 (en) | 2011-05-30 | 2016-01-26 | The Babcock & Wilcox Company | Catalysts possessing an improved resistance to poisoning |
US11229901B2 (en) | 2016-12-20 | 2022-01-25 | Umicore Ag & Co. Kg | SCR catalyst device containing vanadium oxide and molecular sieve containing iron |
US11300029B2 (en) | 2016-12-20 | 2022-04-12 | Umicore Ag & Co, Kg | SCR catalyst device containing vanadium oxide and molecular sieve containing iron |
WO2022093803A1 (en) * | 2020-10-27 | 2022-05-05 | Hasbro Inc. | Stretch compound and method of making the same |
Families Citing this family (46)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4215481A1 (en) * | 1992-05-11 | 1993-11-18 | Siemens Ag | Fine honeycomb ceramic catalyst for nitrogen oxide(s) redn. in waste gas - contg. e.g. one or more of titanium di:oxide, tungsten oxide, molybdenum oxide and vanadium oxide |
JPH0768172A (en) * | 1993-07-20 | 1995-03-14 | Sakai Chem Ind Co Ltd | Catalyst for catalyst production of nox and method thereof |
CN1091637C (en) * | 1994-05-30 | 2002-10-02 | 西门子公司 | Denox catalyst for reducing the NOx concentration in a stream of fluid, and method of mfg. the catalyst |
DE69619327T2 (en) * | 1995-10-09 | 2002-07-18 | Shell Internationale Research Maatschappij B.V., Den Haag/S'gravenhage | Catalyst and process for converting nitrogen oxides |
JP3379627B2 (en) * | 1996-08-30 | 2003-02-24 | 株式会社キャタラー | Exhaust gas purification catalyst |
DE19844758C1 (en) * | 1998-09-29 | 2000-07-06 | Siemens Ag | Process for the production of a catalyst body |
DE19903533A1 (en) | 1999-01-29 | 2000-08-10 | Degussa | Process for the selective catalytic reduction of nitrogen oxides in oxygen-containing exhaust gases |
DE10021071C1 (en) | 2000-04-29 | 2002-03-07 | Omg Ag & Co Kg | Process for removing nitrogen oxides from a flue gas stream containing oxygen |
DE10103771A1 (en) | 2001-01-27 | 2002-08-14 | Omg Ag & Co Kg | Method for restoring the catalytic activity of a catalyst which is arranged in the exhaust tract of a diesel engine and has at least one oxidation function |
DE10124549A1 (en) | 2001-05-19 | 2002-11-28 | Degussa | Reduction of nitrogen oxides in vehicle exhaust gases involves selective catalytic reduction with ammonia produced by contacting rich fuel/air mixture containing nitric oxide with three-way catalyst |
DE102005044494B3 (en) * | 2005-09-16 | 2007-03-08 | Wenzel, Lothar | Device for removing harmful components from exhaust gases of internal combustion engines |
KR101362685B1 (en) | 2006-07-08 | 2014-02-13 | 우미코레 아게 운트 코 카게 | Textured SCR catalyst for the reduction of nitrogen oxides from the exhaust gases of a lean-mixture engine with the use of ammonia as reducing agent |
DE102006031724B3 (en) * | 2006-07-08 | 2008-04-30 | Umicore Ag & Co. Kg | Structured selective catalytic reduction-catalyst, useful for removing nitrogen oxide in exhaust gas, comprises catalytically active material zones of iron-exchanged zeolite and transition metal-exchanged zeolite |
KR101434936B1 (en) | 2006-10-23 | 2014-08-27 | 우미코레 아게 운트 코 카게 | Vanadium-free catalyst for selective catalytic reduction and process for its preparation |
WO2008096413A1 (en) * | 2007-02-06 | 2008-08-14 | Ibiden Co., Ltd. | Honeycomb structure |
EP2112339A1 (en) | 2008-04-24 | 2009-10-28 | Umicore AG & Co. KG | Method and device for cleaning exhaust gases of a combustion motor |
JP5886042B2 (en) | 2008-05-07 | 2016-03-16 | ユミコア・アクチエンゲゼルシャフト・ウント・コムパニー・コマンディットゲゼルシャフトUmicore AG & Co.KG | Method for reducing nitrogen oxides in exhaust gases containing hydrocarbons using SCR catalysts based on molecular sieves |
EP2138681B1 (en) | 2008-06-27 | 2019-03-27 | Umicore AG & Co. KG | Method and device for cleaning diesel exhaust gases |
US8246923B2 (en) | 2009-05-18 | 2012-08-21 | Umicore Ag & Co. Kg | High Pd content diesel oxidation catalysts with improved hydrothermal durability |
US8557203B2 (en) | 2009-11-03 | 2013-10-15 | Umicore Ag & Co. Kg | Architectural diesel oxidation catalyst for enhanced NO2 generator |
CN101757937B (en) * | 2009-11-24 | 2012-08-29 | 江苏工业学院 | Titanium dioxide intercalation photocatalysed composite material and preparation method thereof |
KR20130097076A (en) | 2010-04-20 | 2013-09-02 | 우미코레 아게 운트 코 카게 | Novel mixed oxide materials for the selective catalytic reduction of nitrogen oxides in exhaust gases |
US8758711B2 (en) * | 2010-12-20 | 2014-06-24 | Mitsubishi Heavy Industries, Ltd. | Carrier for NOx reduction catalyst |
FR2972366B1 (en) * | 2011-03-08 | 2016-01-15 | Rhodia Operations | PROCESS FOR TREATING A GAS CONTAINING NITROGEN OXIDES (NOX) USING AS A CATALYST A COMPOSITION BASED ON ZIRCONIUM, CERIUM AND NIOBIUM |
WO2012168277A1 (en) | 2011-06-07 | 2012-12-13 | Umicore Ag & Co. Kg | Catalytic converter for the selective catalytic reduction of nitrogen oxides in the exhaust gas of diesel engines |
DE102012013288A1 (en) * | 2012-07-05 | 2014-01-09 | Man Truck & Bus Ag | Catalyst, process for the preparation of the catalyst, use of the catalyst |
CN104797333A (en) * | 2012-11-08 | 2015-07-22 | 揖斐电株式会社 | Honeycomb structure |
WO2014073065A1 (en) * | 2012-11-08 | 2014-05-15 | イビデン株式会社 | Honeycomb structure and manufacturing method thereof |
WO2014073066A1 (en) * | 2012-11-08 | 2014-05-15 | イビデン株式会社 | Honeycomb structure and manufacturing method thereof |
EP2772302A1 (en) | 2013-02-27 | 2014-09-03 | Umicore AG & Co. KG | Hexagonal oxidation catalyst |
EP2875863A1 (en) * | 2013-11-25 | 2015-05-27 | Umicore AG & Co. KG | SCR catalytic converter |
JP2015147165A (en) * | 2014-02-05 | 2015-08-20 | イビデン株式会社 | Honeycomb catalyst and production method of honeycomb catalyst |
DE102014113784A1 (en) | 2014-09-24 | 2016-03-24 | Umicore Ag & Co. Kg | Process for the preparation of a vanadium-containing catalyst |
DE102014113786A1 (en) | 2014-09-24 | 2016-03-24 | Umicore Ag & Co. Kg | Process for the preparation of a tungsten-containing catalyst |
US10737258B2 (en) * | 2015-10-28 | 2020-08-11 | Umicore Ag & Co. Kg | Honeycomb catalyst for removal of nitrogen oxides in flue and exhaust gasses and method of preparation thereof |
CN108136372B (en) * | 2015-10-28 | 2021-08-31 | 托普索公司 | Monolithic honeycomb oxidation catalyst and preparation method thereof |
WO2018069199A1 (en) | 2016-10-10 | 2018-04-19 | Umicore Ag & Co. Kg | Catalytic converter arrangement |
CN108283921A (en) * | 2018-01-10 | 2018-07-17 | 北京国电龙源环保工程有限公司 | 60 hole SCR denitration modules and preparation method thereof |
KR102067668B1 (en) * | 2018-03-02 | 2020-01-17 | 한국과학기술연구원 | Catalyst for selectively reducing nitric oxide and nitric oxide reduction system using the same |
CN108927142A (en) * | 2018-06-29 | 2018-12-04 | 凯龙高科技股份有限公司 | A kind of monoblock type SCR catalyst and its preparation method and application |
WO2021194043A1 (en) | 2020-03-25 | 2021-09-30 | 한국과학기술연구원 | Catalyst for fenton reaction system comprising metal oxide containing functional group on surface thereof, and fenton reaction system using same |
KR102327831B1 (en) | 2020-03-25 | 2021-11-18 | 한국과학기술연구원 | Catalysts containing sulfate-functionalized metal oxide for electro-fenton reaction system, electrode comprising the same and electro-fenton reaction system using the same |
KR102327832B1 (en) | 2020-03-25 | 2021-11-18 | 한국과학기술연구원 | Nitrate-functionalized transition metal oxide catalysts for the degradation of recalcitrant contaminants and degradation reaction system using the same |
WO2022058404A1 (en) | 2020-09-18 | 2022-03-24 | Umicore Ag & Co. Kg | Scr catalyst compositions and scr catalytic articles comprising said catalyst compositions |
KR102438438B1 (en) * | 2020-11-25 | 2022-09-01 | 한서대학교 산학협력단 | Low Temperature SCR Catalyst for Treating of the Exhaust Gas from a Fixed Source and Preparation Method Thereof |
EP4063003A1 (en) | 2021-03-23 | 2022-09-28 | UMICORE AG & Co. KG | Filter for the aftertreatment of exhaust gases of internal combustion engines |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4048112A (en) * | 1973-09-10 | 1977-09-13 | Mitsubishi Chemical Industries Ltd. | Catalyst for selective reduction of nitrogen oxides |
US4085193A (en) * | 1973-12-12 | 1978-04-18 | Mitsubishi Petrochemical Co. Ltd. | Catalytic process for reducing nitrogen oxides to nitrogen |
DE2846476C3 (en) * | 1977-10-26 | 1982-01-21 | Babcock-Hitachi K.K., Tokyo | Sintered product containing titanium dioxide and method for sintering powdered titanium dioxide |
JPS56168835A (en) * | 1980-05-31 | 1981-12-25 | Mitsubishi Petrochem Co Ltd | Denitrating catalyst and denitrating method |
JPH064126B2 (en) * | 1985-06-10 | 1994-01-19 | 株式会社日本触媒 | Exhaust gas purification method |
DE3531809A1 (en) * | 1985-09-06 | 1987-03-26 | Kraftwerk Union Ag | CATALYST MATERIAL FOR REDUCING NITROGEN OXIDES |
DE3531810A1 (en) * | 1985-09-06 | 1987-03-19 | Kraftwerk Union Ag | CATALYST MATERIAL FOR REDUCING NITROGEN OXIDES |
JP2548754B2 (en) * | 1987-12-02 | 1996-10-30 | 三菱重工業株式会社 | Nitrogen oxide removal catalyst |
-
1989
- 1989-02-28 DE DE3906136A patent/DE3906136C1/de not_active Expired - Lifetime
-
1990
- 1990-02-12 DK DK90102664.1T patent/DK0385164T3/en active
- 1990-02-12 ES ES199090102664T patent/ES2046549T3/en not_active Expired - Lifetime
- 1990-02-12 EP EP90102664A patent/EP0385164B1/en not_active Revoked
- 1990-02-12 AT AT90102664T patent/ATE95443T1/en not_active IP Right Cessation
- 1990-02-12 DE DE90102664T patent/DE59002961D1/en not_active Revoked
- 1990-02-21 AU AU50026/90A patent/AU615375B2/en not_active Ceased
- 1990-02-23 BR BR909000900A patent/BR9000900A/en active Search and Examination
- 1990-02-27 DD DD90338193A patent/DD296854A5/en not_active IP Right Cessation
- 1990-02-27 KR KR1019900002491A patent/KR900012674A/en not_active Application Discontinuation
- 1990-02-27 RU SU904743365A patent/RU2058814C1/en active
- 1990-02-27 CA CA002010970A patent/CA2010970A1/en not_active Abandoned
- 1990-02-28 JP JP2046018A patent/JPH02290250A/en active Pending
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5120695A (en) * | 1989-07-28 | 1992-06-09 | Degusaa Aktiengesellschaft (Degussa Ag) | Catalyst for purifying exhaust gases from internal combustion engines and gas turbines operated at above the stoichiometric ratio |
US8863507B2 (en) | 2008-04-11 | 2014-10-21 | Umicore Ag & Co. Kg | Exhaust gas purification system for the treatment of engine exhaust gases by means of SCR catalyst |
US9242211B2 (en) | 2011-05-30 | 2016-01-26 | The Babcock & Wilcox Company | Catalysts possessing an improved resistance to poisoning |
US11229901B2 (en) | 2016-12-20 | 2022-01-25 | Umicore Ag & Co. Kg | SCR catalyst device containing vanadium oxide and molecular sieve containing iron |
US11300029B2 (en) | 2016-12-20 | 2022-04-12 | Umicore Ag & Co, Kg | SCR catalyst device containing vanadium oxide and molecular sieve containing iron |
WO2022093803A1 (en) * | 2020-10-27 | 2022-05-05 | Hasbro Inc. | Stretch compound and method of making the same |
Also Published As
Publication number | Publication date |
---|---|
KR900012674A (en) | 1990-09-01 |
AU5002690A (en) | 1990-09-06 |
DE3906136C1 (en) | 1990-08-09 |
RU2058814C1 (en) | 1996-04-27 |
ATE95443T1 (en) | 1993-10-15 |
EP0385164A3 (en) | 1990-11-28 |
DD296854A5 (en) | 1991-12-19 |
EP0385164A2 (en) | 1990-09-05 |
JPH02290250A (en) | 1990-11-30 |
DK0385164T3 (en) | 1994-02-28 |
AU615375B2 (en) | 1991-09-26 |
DE59002961D1 (en) | 1993-11-11 |
BR9000900A (en) | 1991-02-13 |
ES2046549T3 (en) | 1994-02-01 |
EP0385164B1 (en) | 1993-10-06 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CA2010970A1 (en) | Catalyst for the selective reduction of nitrogen oxides with ammonia | |
US5300472A (en) | Catalyst for selective reduction of nitrous oxides with ammonia | |
US4916107A (en) | Catalyst for the selective reduction of nitrogen oxides with ammonia | |
US4113660A (en) | Production of shaped catalysts or carriers comprising titanium oxides | |
US4720476A (en) | Catalyst for decreasing the content of nitrogen oxides in flue gases | |
US4857296A (en) | CeO catalytic desulfurization of industrial gases | |
US5010052A (en) | Zirconium dioxide gas desulfurization catalyst | |
US5106607A (en) | Multilobar catalysts for the conversion of sulfur containing gaseous effluents | |
CA1265119A (en) | Catalyst for combustion and process for producing same | |
EP3714974A1 (en) | Lanthanum-based perovskite-type catalyst compositions stable to ageing in three-way catalysis | |
CN109967069A (en) | A kind of low-temperature SCR catalyst and preparation method thereof for cement kiln flue gas denitration | |
CN111841526B (en) | Modified Ce-Ti medium-low temperature flue gas denitration catalyst powder and preparation method thereof | |
US4946661A (en) | Process for removing nitrogen oxides | |
CN114011400A (en) | Preparation method of acid system waste incineration SCR denitration catalyst and prepared denitration catalyst | |
CN110694612A (en) | Rare earth-based low-vanadium medium-low temperature flue gas denitration catalyst and preparation method thereof | |
CN110354837B (en) | Alpha-alumina carrier and preparation method and application thereof | |
EP1192991B1 (en) | A method for preparing a catalyst for selective catalytic reduction of nitrogen oxides | |
EP0257307B1 (en) | A method for denitrizing nitrogen oxides contained in waste gas | |
US3976745A (en) | Process for reducing nitrogen oxides to nitrogen | |
US3962138A (en) | Cobalt-oxide-based catalytic substances for the oxidation of ammonia | |
RU2368417C1 (en) | Catalyst and method of converting ammonia | |
JPH0256245A (en) | Catalyst for removing nitrogen oxide | |
CN118304874A (en) | Alpha-alumina carrier, preparation method thereof, silver catalyst and method for producing ethylene oxide by ethylene epoxidation | |
JPH02241543A (en) | Preparation of catalyst for reducing nitrogen oxide | |
RU2026111C1 (en) | Method for manufacture of catalyst for oil fraction hydrorefining |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
EEER | Examination request | ||
FZDE | Discontinued |