JP4538198B2 - Titanium dioxide powder for honeycomb exhaust gas treatment catalyst and honeycomb exhaust gas treatment catalyst using the titanium dioxide powder - Google Patents
Titanium dioxide powder for honeycomb exhaust gas treatment catalyst and honeycomb exhaust gas treatment catalyst using the titanium dioxide powder Download PDFInfo
- Publication number
- JP4538198B2 JP4538198B2 JP2003102306A JP2003102306A JP4538198B2 JP 4538198 B2 JP4538198 B2 JP 4538198B2 JP 2003102306 A JP2003102306 A JP 2003102306A JP 2003102306 A JP2003102306 A JP 2003102306A JP 4538198 B2 JP4538198 B2 JP 4538198B2
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- titanium dioxide
- honeycomb
- exhaust gas
- gas treatment
- treatment catalyst
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- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims description 586
- 239000004408 titanium dioxide Substances 0.000 title claims description 263
- 239000003054 catalyst Substances 0.000 title claims description 231
- 239000000843 powder Substances 0.000 title claims description 169
- 239000007789 gas Substances 0.000 claims description 169
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical group O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims description 99
- 239000013078 crystal Substances 0.000 claims description 51
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 42
- 239000010936 titanium Substances 0.000 claims description 41
- 229910052719 titanium Inorganic materials 0.000 claims description 41
- 239000002131 composite material Substances 0.000 claims description 34
- 238000000034 method Methods 0.000 claims description 32
- 239000013074 reference sample Substances 0.000 claims description 29
- 239000002245 particle Substances 0.000 claims description 20
- 238000005192 partition Methods 0.000 claims description 20
- 238000000634 powder X-ray diffraction Methods 0.000 claims description 19
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 16
- 239000003153 chemical reaction reagent Substances 0.000 claims description 6
- 229910052721 tungsten Inorganic materials 0.000 claims description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 4
- 229910052750 molybdenum Inorganic materials 0.000 claims description 4
- 229910000480 nickel oxide Inorganic materials 0.000 claims description 4
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 239000010703 silicon Substances 0.000 claims description 4
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 4
- 239000010937 tungsten Substances 0.000 claims description 4
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 3
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 3
- 239000011733 molybdenum Substances 0.000 claims description 3
- 239000004570 mortar (masonry) Substances 0.000 claims description 3
- 229910052726 zirconium Inorganic materials 0.000 claims description 3
- 241000282994 Cervidae Species 0.000 claims description 2
- 229910010413 TiO 2 Inorganic materials 0.000 description 31
- 230000000052 comparative effect Effects 0.000 description 27
- 239000000203 mixture Substances 0.000 description 24
- 238000002360 preparation method Methods 0.000 description 24
- 238000001125 extrusion Methods 0.000 description 19
- 239000003365 glass fiber Substances 0.000 description 19
- 239000002994 raw material Substances 0.000 description 17
- 230000000694 effects Effects 0.000 description 15
- 239000002002 slurry Substances 0.000 description 15
- 229910004298 SiO 2 Inorganic materials 0.000 description 14
- 239000004927 clay Substances 0.000 description 14
- 229910052809 inorganic oxide Inorganic materials 0.000 description 13
- 239000002253 acid Substances 0.000 description 11
- 238000004898 kneading Methods 0.000 description 11
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 10
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 10
- 239000011148 porous material Substances 0.000 description 10
- QAOWNCQODCNURD-UHFFFAOYSA-L sulfate group Chemical group S(=O)(=O)([O-])[O-] QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 10
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 9
- 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 9
- 239000000523 sample Substances 0.000 description 9
- 229910001930 tungsten oxide Inorganic materials 0.000 description 9
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 8
- 235000011114 ammonium hydroxide Nutrition 0.000 description 8
- 239000000428 dust Substances 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- 150000002896 organic halogen compounds Chemical class 0.000 description 7
- 239000010949 copper Substances 0.000 description 6
- 230000018044 dehydration Effects 0.000 description 6
- 238000006297 dehydration reaction Methods 0.000 description 6
- 238000010304 firing Methods 0.000 description 6
- 238000005259 measurement Methods 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 5
- 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 5
- 239000000377 silicon dioxide Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 229910000348 titanium sulfate Inorganic materials 0.000 description 5
- 238000002485 combustion reaction Methods 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- 238000011056 performance test Methods 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 238000006722 reduction reaction Methods 0.000 description 4
- 239000011163 secondary particle Substances 0.000 description 4
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 description 3
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 3
- -1 WO 3 Inorganic materials 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 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 3
- 239000004480 active ingredient Substances 0.000 description 3
- 229910021529 ammonia Inorganic materials 0.000 description 3
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 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 3
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 238000001935 peptisation Methods 0.000 description 3
- 238000010992 reflux Methods 0.000 description 3
- 239000004576 sand Substances 0.000 description 3
- 229910001935 vanadium oxide Inorganic materials 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229910052684 Cerium Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 2
- JJWKPURADFRFRB-UHFFFAOYSA-N carbonyl sulfide Chemical compound O=C=S JJWKPURADFRFRB-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
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- 229910052748 manganese Inorganic materials 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000011268 mixed slurry Substances 0.000 description 2
- 229910000476 molybdenum oxide Inorganic materials 0.000 description 2
- PQQKPALAQIIWST-UHFFFAOYSA-N oxomolybdenum Chemical compound [Mo]=O PQQKPALAQIIWST-UHFFFAOYSA-N 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- 231100000331 toxic Toxicity 0.000 description 2
- 230000002588 toxic effect Effects 0.000 description 2
- KVGZZAHHUNAVKZ-UHFFFAOYSA-N 1,4-Dioxin Chemical compound O1C=COC=C1 KVGZZAHHUNAVKZ-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- HGWOWDFNMKCVLG-UHFFFAOYSA-N [O--].[O--].[Ti+4].[Ti+4] Chemical compound [O--].[O--].[Ti+4].[Ti+4] HGWOWDFNMKCVLG-UHFFFAOYSA-N 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
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- 238000010586 diagram Methods 0.000 description 1
- 150000002013 dioxins Chemical class 0.000 description 1
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- 239000000295 fuel oil Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
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- 229910052741 iridium Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000005078 molybdenum compound Substances 0.000 description 1
- 150000002752 molybdenum compounds Chemical class 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
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- 229910052709 silver Inorganic materials 0.000 description 1
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- 150000003658 tungsten compounds Chemical class 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- 150000003682 vanadium compounds Chemical class 0.000 description 1
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- 229910052727 yttrium Inorganic materials 0.000 description 1
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- Inorganic Compounds Of Heavy Metals (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、ハニカム状排ガス処理触媒用二酸化チタン粉末及びその二酸化チタン粉末を使用したハニカム状排ガス処理触媒に関するものであり、更に詳しくは、重油や石炭焚きボイラ、火力発電所、製鉄所などをはじめ各種工場の燃焼炉やゴミ焼却炉などから排出される排ガス中に含有される窒素酸化物や有機ハロゲン化合物、さらには、アンモニア、硫化カルボニル、揮発性有機化合物などを高効率で除去する二酸化チタン（以下、酸化チタンということがある）および／またはチタン複合酸化物からなるハニカム状排ガス処理触媒用二酸化チタン粉末及びその二酸化チタン粉末を使用したハニカム状排ガス処理触媒に関するものである。
【０００２】
【従来の技術】
火力発電所、製鉄所などをはじめ各種工場の燃焼炉や都市ゴミ、産業廃棄物などを処理する焼却炉などから排出される燃焼排ガス中には窒素酸化物や有機ハロゲン化合物など各種の有害物質が含有されているが、なかでも、窒素酸化物は光化学スモッグの原因物質であるため、また、ダイオキシンなど有機ハロゲン化合物は毒性が強いため、その除去は特に重要である。
【０００３】
燃焼排ガス中の窒素酸化物の除去方法としては、各種の方法が知られているが、触媒によるアンモニア選択還元方式（ＳＣＲ）が主流で、これに用いられる触媒としては、酸化チタン担体に酸化タングステン、酸化バナジウムなどの活性成分を担持した触媒が主流である。例えば、特許文献１には、アナターゼ構造のチタニアを主成分とし、これに活性成分としてバナジウム化合物、またはその他にモリブデン化合物とタングステン化合物のうち一つ以上を担持させた脱硝触媒の製造方法において、チタニア担体中のアナターゼの一部をルチル化させ、高比表面積であるアナターゼにルチル粒子を分散させることにより、粉末Ｘ線回折法によるルチル／アナターゼのピークの積分強度比が０．００１〜０．０５の範囲で、かつ触媒の比表面積が３０ｍ２／ｇ以上になるように焼成すると脱硝活性が高い脱硝触媒が得られることが記載されている。
【０００４】
また、特許文献２には、脱硝などの用途において優れた触媒活性を示す多孔質チタニアとして、アナターゼ型の結晶構造を有し、その結晶子径が３ｎｍ〜１０ｎｍ、アナターゼ結晶化率が６０％以上、ＢＥＴ比表面積が１０ｍ２／ｇ以上、全細孔容積が０．０５ｃｍ３／ｇ以上、１ｎｍ以上の細孔半径を有する細孔の容積が０．０２ｃｍ３／ｇ以上であることを特徴とする多孔質チタニアが開示されている。
【０００５】
特許文献３には、排ガス処理用触媒および排ガス処理方法が提案されているが、該公報には、アモルファス相の酸化チタンを含有する排ガス処理用触媒において、粉末Ｘ線回折の２θ＝２４．７°〜２５．７°の間に存在するアナタース結晶を示すピークの強度が、基準物質である５重量％Ｖ２Ｏ５−９５重量％ＴｉＯ２（ミレニアム社製酸化チタンＤＴ−５１）の粉末Ｘ線回折の２θ＝２４．７°〜２５．７°の間に存在するアナタース結晶を示すピークの強度の７５％以下であることを特徴とする排ガス処理用触媒が開示されており、アナタース結晶を示すピークの強度が小さければ小さいほど、アナタース型の酸化チタンの割合が少なく、アモルファス相の酸化チタンの割合が多い傾向にあり、ダイオキシン類などの毒性有機ハロゲン化合物の分解活性や脱硝活性が高いことが記載されている。
【０００６】
前述のように、従来、酸化チタン担体に酸化タングステン、酸化バナジウムなどの活性成分を担持した脱硝触媒に於いて、脱硝活性はアナターゼ型二酸化チタン結晶の結晶化度の高い方が高活性であるという説と、該結晶化度の低い方が高活性であるという説があり、アナターゼ型二酸化チタン結晶の結晶化度と脱硝活性との関係は明らかになっていなかった。
【０００７】
一方、排ガス処理触媒の形状は、ハニカム状、円柱状、球状、板状などが挙げられるが、工業的に使用される触媒としては触媒層でダストが堆積、目詰まりしにくいハニカム形状が適している。ハニカム形状の触媒を製造する方法としては、（ａ）担体成分をハニカム形状に押出成形した後、活性成分を含浸・担持する方法、または、担体成分と活性成分を成形助材等と共に混練してハニカム形状に押出成形する方法、（ｂ）ハニカム形状の基材上に担体成分および活性成分を含浸・担持する方法などが知られている。（ａ）方法の触媒はソリッドタイプの触媒と言われており脱硝活性が高いので、現在、主流となっている。
【０００８】
従来、発電所等のボイラー排ガス量は、一基当たり１００，０００〜２，０００，０００Ｎｍ３／ｈｒと非常に多いため、該排ガスを処理するために使用される触媒量が増加するという問題があった。この問題を解決するために、排ガス中のダストが少ないガス焚き用の触媒においてはハニカム状触媒の単位体積当たりの幾何学的表面積を増加させ窒素酸化物などの除去効率を高めるためにハニカム構造体の隔壁厚さを薄くし貫通孔の数を増加させた触媒が要求されるようになって来た。しかしながら、酸化チタンおよび／またはチタン複合酸化物の粉末を主成分とするハニカム状排ガス処理触媒用原料は成形性が悪く、前記隔壁厚さが薄く貫通孔の数が増加したハニカム構造体を押出成形することは困難であった。
また、石炭焚きボイラー排ガス中には、硬いガラス状のダストが１０〜２５ｇ／Ｎｍ３程度含まれており、さらに、脱硝反応装置内の排ガスの流速が極めて速いために、触媒の摩耗による減少が多くなるという問題があり、高い耐摩耗強度を有するハニカム状排ガス処理触媒が求められていた。
【０００９】
【特許文献１】
特開平８−２８１１０３号公報
【特許文献２】
特開２００１―１１４５１９号公報
【特許文献３】
特開２００１−１１３１６９号公報
【００１０】
【発明が解決しようとする課題】
本発明は、前述の実情に鑑みなされたものであり、その目的は、ハニカムの隔壁厚さが薄く貫通孔の数が増加したハニカム構造体の押出成形性に優れた二酸化チタンおよび／またはチタン複合酸化物の粉末からなるハニカム状排ガス処理触媒用二酸化チタン粉末およびその二酸化チタン粉末を使用した高脱硝活性を有する触媒や有機ハロゲン化合物の高分解活性を有する触媒を提供することにある。さらには、ダストを多く含む石炭焚きボイラー排ガス処理などに使用して、高い耐摩耗強度を有するハニカム状排ガス処理触媒を提供することにある。
【００１１】
【課題を解決するための手段】
本発明者らは、種々検討を重ねた結果、二酸化チタン担体に酸化タングステン、酸化バナジウムなどの活性成分を担持した脱硝触媒などの排ガス処理触媒に於いて、ハニカム状排ガス処理触媒の原料であるアナターゼ型二酸化チタンの結晶度が低い方が窒素酸化物除去性能などは高くなるが、一方、ハニカム構造体の押出成形性はアナターゼ型二酸化チタンの結晶度が低くなると悪くなり、逆に、アナターゼ型二酸化チタンの結晶度が高い方が押出成形性が良いことを見出して、脱硝活性面とハニカム構造体の押出成形性面の両面から見てアナターゼ型二酸化チタン結晶度に最適な範囲が存在すること、更に、原料の二酸化チタンに含有される硫酸根（ＳＯ４）の量、二酸化チタンの結晶子径の大きさ、二酸化チタン粉末の粒径分布により触媒の押出成形性、耐摩耗強度が影響されるを見出し本発明を完成するに至った。
【００１２】
本発明の第１は、二酸化チタンおよび／またはチタン複合酸化物（本発明でいうチタン複合酸化物とはチタニウム以外の無機酸化物を含有する二酸化チタンを指す）からなるハニカム状排ガス処理触媒用二酸化チタン粉末であって、下記
（ａ）粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面の二酸化チタン粉末の基準試料に対するピーク強度比が下記式（１）
【数２】
０．５９≦Ｘ／Ｙ≦１．２０ （１）
〔ここで、Ｙは、純粋なアナターゼ型二酸化チタン（関東化学製：試薬鹿１級）０．３００ｇと純粋な酸化ニッケル（和光純薬製：試薬１級）１．７００ｇをメノウ乳鉢で粉砕混合した基準試料のアナターゼ型二酸化チタン結晶の（１０１）面のピーク強度（ｍｍ）であり、Ｘは、ハニカム状排ガス処理触媒用二酸化チタン粉末のアナターゼ型二酸化チタン結晶の（１０１）面のピーク強度（ｍｍ）である〕
で表される範囲にある、
（ｂ）アナターゼ型結晶（１０１）面の結晶子径が８〜２２ｎｍの範囲にある、
（ｃ）硫酸根（ＳＯ４）を０．３〜５．０重量％の範囲で含有する、
の性状を有することを特徴とするハニカム状排ガス処理触媒用二酸化チタン粉末に関する。
本発明の第２は、前記チタン複合酸化物がケイ素、タングステン、モリブデン、ジルコニウムから選ばれた少なくとも一種の元素とチタンとの複合酸化物であることを特徴とする請求項１記載のハニカム状排ガス処理触媒用二酸化チタン粉末に関する。
本発明の第３は、前記二酸化チタン粉末は９９．９重量％以上が４５μｍ以下の粒子径であることを特徴とする請求項１または２記載のハニカム状排ガス処理触媒用二酸化チタン粉末に関する。
本発明の第４は、請求項１、２または３記載のハニカム状排ガス処理触媒用二酸化チタン粉末を６０重量％以上含有することを特徴とするハニカム状排ガス処理触媒に関する。
本発明の第５は、前記ハニカム状排ガス処理触媒が、下記（ｉ）〜（ｖ）の形状を有するハニカム構造体であることを特徴とする請求項４記載のハニカム状排ガス処理触媒に関する。
（ｉ）ハニカムの外径が３０〜３００ｍｍ、
（ii）ハニカムの長さが１００〜３０００ｍｍ、
（iii）ハニカムの貫通孔が１〜１５ｍｍ、
（iv）ハニカムの隔壁厚が０．１〜２ｍｍ、
（ｖ）ハニカムの開口率が６０〜８５％
本発明の第６は、前記ハニカム状排ガス処理触媒が窒素酸化物除去触媒であることを特徴とする請求項４または５記載のハニカム状排ガス処理触媒に関する。
【００１３】
【発明の実施の形態】
以下、本発明の好適な実施形態について、詳細に説明する。
【００１４】
本発明におけるハニカム状排ガス処理触媒用二酸化チタン（ＴｉＯ２）またはチタン複合酸化物の粉末は、アナターゼ型の結晶構造を有するものであり、とくに前記チタン複合酸化物は、ハニカム状排ガス処理触媒用の二酸化チタン粉末以外に、例えば、ケイ素（Ｓｉ）、ジルコニウム（Ｚｒ）、タングステン（Ｗ）、モリブデン（Ｍｏ）、バナジウム（Ｖ）、マンガン（Ｍｎ）、銅（Ｃｕ）、スズ（Ｓｎ）、バリウム（Ｂａ）、セリウム（Ｃｅ）などのチタニウム（以下チタンという）以外の元素よりなる無機酸化物を１種以上含有する二酸化チタンと前記無機酸化物よりなる化合物またはその混合物であり、この複合酸化物中の二酸化チタンはアナターゼ型の結晶構造を有する。特に、二酸化チタンおよびシリカ（ＴｉＯ２−ＳｉＯ２）、二酸化チタンおよび酸化タングステン（ＴｉＯ２−ＷＯ３）、二酸化チタンおよび酸化モリブデン（ＴｉＯ２−ＭｏＯ３）、二酸化チタンおよびジルコニア（ＴｉＯ２−ＺｒＯ２）のいわゆる二元系複合酸化物、また二酸化チタンと酸化タングステンおよびシリカ（ＴｉＯ２−ＷＯ３−ＳｉＯ２）、二酸化チタンと酸化モリブデンおよびシリカ（ＴｉＯ２−ＭｏＯ３−ＳｉＯ２）の三元系複合酸化物は、ＴｉＯ２にＳｉＯ２、ＷＯ３、ＭｏＯ３が高分散した構造を有し加熱焼成による結晶化の進行やルチル型ＴｉＯ２への転移を抑制する性質を有するので好適である。
チタン以外の無機酸化物の含有量は、二酸化チタンの量よりも少ないことが好ましく、０．５〜４０重量％の範囲にあることが望ましい。チタン以外の無機酸化物の含有量が二酸化チタンの量よりも多くなると排ガス処理触媒、特に窒素酸化物除去触媒の酸化チタン担体としての優れた効果が得られないことがある。
【００１５】
一般に、ピーク強度の高い二酸化チタンおよび／またはチタン複合酸化物は、押出成形に際しての捏和の段階でニーダーなどによる湿式下での混練による機械的負荷が加わると凝集した二酸化チタンの二次粒子が解膠されて適度な可塑性および流動性を呈するため、押出成形がし易いものとなる。また、二酸化チタン二次粒子の解膠は、粒子間隙が二酸化チタン一次粒子で充填されるため、成形されたハニカム状触媒の機械強度も極めて高いものとなる。
ところが、二酸化チタン二次粒子の解膠は、粒子間隙が二酸化チタン一次粒子で充填されるため細孔容積が小さくなるので細孔内のガス拡散効率が低下し、窒素酸化物除去性能などが低下する。さらには、ピーク強度の高い二酸化チタンおよび／またはチタン複合酸化物は、結晶化が進行しているため結晶子径が大きく比表面積も低下し、担持されたＶ２Ｏ５などの活性金属の凝集が起こり窒素酸化物除去性能などの低下をもたらす。
【００１６】
これに反し、ピーク強度の低い二酸化チタンおよび／またはチタン複合酸化物は、押出成形の段階で捏和物が脱水固化する現象などが生じて流動性が悪くなるため、押出成形が著しく難しいものとなる。
しかし、ピーク強度の低い二酸化チタンおよび／またはチタン複合酸化物は、押出成形に際しての捏和の段階でニーダーなどによる湿式下での混練による機械的負荷による凝集した二酸化チタンの二次粒子の解膠される割合が小さいために粒子間隙の細孔容積の減少が小さく細孔内のガス拡散効率の低下が少なく、高い窒素酸化物除去性能などを示す。さらには、ピーク強度の低い二酸化チタンおよび／またはチタン複合酸化物は、結晶化が進行していないので結晶子径が小さく比表面積も大きいため、担持されたＶ２Ｏ５などの活性金属は高分散しているので高い窒素酸化物除去性能などをもたらす。
【００１７】
本発明においては、ハニカム状排ガス処理触媒の製造原料として好適な二酸化チタン粉末とはどのようなものであるかを追求した結果、粉末Ｘ線回折法で測定した結晶の（ｈ、ｋ、ｌ）面、すなわち（１０１）面における原料二酸化チタン粉末（チタン複合酸化物の場合でも、そこに存在する二酸化チタンを測定の対象とするものである）の結晶が示すピーク強度（ピークハイト）Ｘと基準試料の結晶が示すピーク強度（ピークハイト）Ｙとの比がある一定の範囲にあることが重要であることを見出したものである。すなわち、
【数３】
０．５９≦Ｘ／Ｙ≦１．２０ （１）
を満足するということが本発明の１つの特徴である。
【００１８】
本発明での粉末Ｘ線回折法のアナターゼ型二酸化チタン結晶度の基準は、純粋なアナターゼ型二酸化チタン（関東化学製：試薬鹿１級、純粋なものであれば、当然この商品に限るものではなく、この商品は１つの目安である）０．３００ｇと純粋な酸化ニッケル（和光純薬製：試薬１級、純粋な酸化ニッケルであれば当然この商品に限るものではなく、この商品は１つの目安である）１．７００ｇをメノウ乳鉢で粉砕混合した基準試料のアナターゼ型二酸化チタン結晶の（１０１）面のピーク強度（以下、ピークハイトという）Ｙ（ｍｍ）で表される。
なお、該基準試料を粉末Ｘ線回折装置（理学電機社製：ＲＡＤ−２Ｃ）を使用して、Ｃｕ管球、フィルターＮｉ、電圧３０ＫＶ、電流１５ｍＡ、走査速度１．０００°／ｍｉｎ、フルスケール１０００ｃｐｓの測定条件で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピークハイトは図１に示すとおりである。本装置での実測データにおいては、（１０１）面のピークは２θ＝２５．２８０〔°〕のピークに相当しており、ピークハイトを定規で実測した高さは１５１ｍｍであった。純粋なアナターゼ型二酸化チタン（関東化学製：試薬鹿１級）だけを測定した実測データにおいては、２θ＝２５．２８０〔°〕のピークに相当するピークハイトを定規で実測した高さは４２１ｍｍであった。従って、本発明での基準資料は、純粋なアナターゼ型二酸化チタン結晶の（１０１）面のピーク強度に対して３５．８７％〔（１５１÷４２１）×１００〕のピーク強度に相当する。このピークハイトの数値は測定条件や測定装置が変わることによって変化する数値であるが、式（１）は対象物と基準物のそれぞれのピークハイトの比に関する式であるから、何の問題もない。
【００１９】
本発明におけるピークハイト比を規定する方法では、該基準試料を設けることにより、粉末Ｘ線回折装置や測定条件などの影響を受けることなく原料のアナターゼ型二酸化チタン結晶の（１０１）面のピークハイト（ｍｍ）をもって触媒原料の二酸化チタン粉末を管理することができる。
【００２０】
前述の二酸化チタンおよび／またはチタン以外の無機酸化物を含有する二酸化チタンにおけるアナターゼ型二酸化チタン結晶の（１０１）面の二酸化チタン粉末の基準試料に対するピークハイト比が０．５９未満の場合には、ハニカム構造体の押出成形が極めて困難であり、かつハニカム状触媒の機械強度が著しく低下する。また、該ピークハイト比が１．２０より大きい場合には、脱硝性能などの触媒活性が低下する。
【００２１】
本発明では、前述のハニカム状排ガス処理触媒用二酸化チタン粉末が二酸化チタンだけの（チタン複合酸化物でない）場合には、前述のピークハイト比は下記式（２）で表される範囲にあることが望ましい。
【数４】
０．８０≦Ｘ／Ｙ≦１．２０ （２）
【００２２】
また、前述のハニカム状排ガス処理触媒用二酸化チタン粉末がチタン以外の無機酸化物を含有する二酸化チタン（チタン複合酸化物）である場合には、前述のピークハイト比は好ましくは下記式（３）で表される範囲にあることが望ましい。複合酸化物の場合、まずチタニア以外の金属酸化物が存在することでチタニアが希釈されそれ自体でピークハイトが低下し、また、ケイ素やタングステンなどがチタニア結晶構造中に固溶するため、チタニア単独と比較して熱履歴に対し結晶成長が抑制されやすい。そのため成形性、性能が共に良いチタン複合酸化物粉末の前述のピークハイト比は二酸化チタンだけの（チタン複合酸化物でない）場合と比較し低くなる。
【数５】
０．５９≦Ｘ／Ｙ≦１．０６ （３）
【００２３】
前述の二酸化チタンおよび／またはチタン複合酸化物の粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピークハイトＸ（ｍｍ）には、二酸化チタンおよび／またはチタン複合酸化物中に含まれる不純物としての硫酸根（ＳＯ４）やアルカリ（Ｎａ２Ｏ）量あるいは複合酸化物を構成する物質の種類や量、焼成温度や焼成雰囲気、焼成時間などが相互に作用して影響する。本発明の二酸化チタンおよび／またはチタン以外の無機酸化物を含有する二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末は、前述のピークハイトＸ（ｍｍ）に影響を及ぼす因子を考慮して、前述のピークハイト比が式（１）を満足するように焼成することで得られる。
【００２４】
また、本発明のハニカム状排ガス処理触媒用二酸化チタン粉末は、アナターゼ型結晶（１０１）面の結晶子径が８〜２２ｎｍの範囲にあることをもう１つの特徴とするものである。なお、該結晶子径はシェラー（Ｓｃｈｅｒｒｅｒ）の式から求めた値である。一般に、純粋な二酸化チタンの結晶子径の大きさとＸ線回折図のピークハイトとは相関関係にあるが、硫酸根などの不純物やチタン以外の無機酸化物を含有する二酸化チタンでは、Ｘ線回折図のピークハイトが同じであっても結晶子径の大きさは異なり、また、含有される無機酸化物の種類、量によっても異なる。従って、本発明のハニカム状排ガス処理触媒用二酸化チタン粉末を前述のピークハイト比だけで規定するのは十分ではない。該結晶子径が８ｎｍより小さい場合には、二酸化チタン粉末の捏和物をハニカム構造体に押出成形する際に脱水現象が生じて押出成形性が悪くなり、隔壁厚さの薄いハニカム構造体が得られない。また、該結晶子径が２２ｎｍより大きい場合には脱硝性能など触媒活性が低下するので好ましくない。
【００２５】
本発明では、前述のハニカム状排ガス処理触媒用二酸化チタン粉末が二酸化チタンだけの（チタン複合酸化物でない）場合には、該結晶子径は好ましくは１５〜２２ｎｍの範囲にあることが望ましく、また、該二酸化チタン粉末がチタン以外の無機酸化物を含有する二酸化チタン（チタン複合酸化物）である場合には、該結晶子径は好ましくは１０〜１９ｎｍの範囲にあることが望ましい。
【００２６】
さらに、本発明のハニカム状排ガス処理触媒用二酸化チタン粉末は、硫酸根（ＳＯ４）をチタン粉末中に乾燥基準でＳＯ４として０．３〜５．０重量％の範囲で含有することを特徴とする。硫酸根（ＳＯ４）の含有量が０．３重量％より少ない場合には、押出成型されたハニカム状触媒の乾燥、焼成時における収縮率が大きくなるため、得られた触媒にひび割れ等が生じ強度が弱くなる。また、触媒の細孔容積、特に細孔直径５００Å以下の細孔容積が小さくなるため窒素酸化物除去性能などが低下するので好ましくない。また、硫酸根（ＳＯ４）の含有量が５．０重量％より多い場合には、二酸化チタン粉末の捏和物をハニカム構造体に押出成形する際に脱水固化する現象などが生じて流動性が悪く、また成形助剤として使用した有機可塑剤などの粘性が低下するため、押出成形が著しく難しいものとなる。該硫酸根（ＳＯ４）の含有量は、好ましくは０．４〜３．５重量％の範囲が望ましい。
【００２７】
また、本発明のハニカム状排ガス処理触媒用二酸化チタン粉末は、９９．９重量％以上が４５μｍ以下の粒子径であることが好ましい。該二酸化チタン粉末の粒子径の４５μｍ以下が９９．９重量％より少ない場合、即ち、４５μｍより大きい粒子径の二酸化チタン粉末が０．１重量％より多い場合には、押出成形した際に隔壁が欠落したハニカム構造体が得られることがある。
【００２８】
本発明のハニカム状排ガス処理触媒は、前述のハニカム状排ガス処理触媒用二酸化チタン粉末を６０重量％以上含有することが好ましい。前述のハニカム状排ガス処理触媒用二酸化チタン粉末が６０重量％より少ない場合には、所望の脱硝活性や有機ハロゲン化合物の分解活性が得られないことがある。本発明のハニカム状排ガス処理触媒は、好ましくは前述のハニカム状排ガス処理触媒用二酸化チタン粉末を７０〜９９．９重量％の範囲で含有することが望ましい。なお、本発明のハニカム状排ガス処理触媒は、前述のハニカム状排ガス処理触媒用二酸化チタン粉末を６０重量％以上含有していれば、本発明の範囲外の酸化チタン粉末を４０重量％未満含有していてもよい。
【００２９】
また、本発明のハニカム状排ガス処理触媒は、通常の窒素酸化物除去用触媒に使用される活性成分を含有する。該活性成分としては、例えば、Ｖ、Ｗ、Ｍｏ、Ｃｒ、Ｍｎ、Ｆｅ、Ｎｉ、Ｃｕ、Ａｇ、Ａｕ、Ｐｄ、Ｙ、Ｃｅ、Ｎｄ、Ｉｎ、Ｉｒなどの金属成分が挙げられる。特に、バナジウム（Ｖ）酸化物は、安価であり且つ窒素酸化物の除去率が高いために好適に使用される。また、活性成分の含有量は、通常の窒素酸化物除去用触媒に使用される活性成分量が使用され、通常、酸化物として触媒中０．１〜３０重量％の範囲である。
【００３０】
前述のハニカム状排ガス処理触媒は、（ａ）前述の二酸化チタンおよび／またはチタン以外の無機酸化物を含有する二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末と活性成分またはその前駆物質を、成形助材等と共に混練して捏和物とした後に、所望のハニカム形状に押出成形し、乾燥、焼成する方法、（ｂ）前述の二酸化チタンおよび／またはチタン以外の無機酸化物を含有する二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末を、成形助材等と共に混練して捏和物とした後に、所望のハニカム形状に押出成形し、乾燥、焼成した担体に、活性成分を含有する水溶液を含浸し、乾燥、焼成する方法などにより製造される。なお、ハニカム状排ガス処理触媒を製造するための条件等は、通常の製造条件が採用可能である。本発明のハニカム構造体を押出成形における押出方向に対して直角の方向に切断したときの断面図の１例を図２に示す。
【００３１】
本発明のハニカム状排ガス処理触媒はハニカム構造体の形状が、（ｉ）ハニカムの外径が好ましくは３０〜３００ｍｍ、更に好ましくは５０〜２００ｍｍ、（ii）ハニカムの長さが１００〜３０００ｍｍ、更に好ましくは３００〜１５００ｍｍ、（iii）ハニカムの貫通孔（以下、目開きということがある）が好ましくは１〜１５ｍｍ、更に好ましくは２〜１０ｍｍ、（iv）ハニカムの隔壁厚が好ましくは０．１〜２ｍｍ、更に好ましくは０．１〜１．５ｍｍ、（ｖ）ハニカムの開口率が好ましくは６０〜８５％、更に好ましくは７０〜８５％の範囲であることが望ましい。該ハニカム構造体の形状が前記形状の範囲を外れる場合には、成形が困難になる、ハニカム構造体の強度が弱くなる、単位体積当たりの脱硝活性や有機ハロゲン化合物の分解活性等が低くなることなどがある。
【００３２】
本発明のハニカム状排ガス処理触媒は、ＮＯｘを含有する排ガス、特にボイラー排ガスなどのようにＮＯｘ、ＳＯｘを含有するほか重金属、ダストを含有する排ガスに、アンモニアなどの還元剤を添加して接触還元するＮＯｘ除去法に好適に使用される。また、該触媒の使用条件は、通常の脱硝処理条件が採用され、具体的には、反応温度は１５０〜６００℃、空間速度１０００〜１０００００ｈｒ―１の範囲などが例示される。
【００３３】
【実施例】
以下、本発明を実施例により詳細に説明するが、本発明はその要旨を超えない限り、以下の実施例により限定されるものではない。
【００３４】
実施例１＜ハニカム状排ガス処理触媒用二酸化チタン粉末の調製（ａ）＞
硫酸法による二酸化チタンの製造工程より得られる硫酸チタン溶液を熱加水分解してメタチタン酸スラリーを得た。このメタチタン酸スラリーを二酸化チタンとして２５．０ｋｇ取り出し、還流器付攪拌槽に仕込み、これに１５重量％アンモニア水３０．５ｋｇを加えてｐＨを９．５に調整した後、９５℃で１時間に亘り十分な攪拌を行いつつ加熱熟成した。その後、冷却して該スラリ−を取り出し、濾過、脱水、洗浄して、ＳＯ４が４．１ｗｔ％（Ｄｒｙ Ｂａｓｉｓ）、Ｎａ２Ｏが０．０３ｗｔ％（Ｄｒｙ Ｂａｓｉｓ）の洗浄ケーキを得た。該洗浄ケーキを１１０℃で２０時間乾燥した後、これを５０９℃で５時間焼成して二酸化チタン粉末を得た。該二酸化チタン粉末をさらに粉砕して二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ａ）を調製した。該二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ａ）を、粉末Ｘ線回折装置（理学電機社製：ＲＡＤ−２Ｃ）を使用して、Ｃｕ管球、フィルターＮｉ、電圧３０ＫＶ、電流１５ｍＡ、走査速度１．０００°／ｍｉｎ、フルスケール１０００ｃｐｓの測定条件で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピークハイトＸは１４０ｍｍで、基準試料のアナターゼ型二酸化チタン結晶の（１０１）面のピークハイトＹは１５１ｍｍであった。そこで、二酸化チタン粉末（ａ）の基準試料に対するピーク強度比は、
【数６】
Ｘ／Ｙ＝１４０／１５１＝０．９３
となり、式（１）の条件を満す。
また、該二酸化チタン粉末（ａ）は、アナターゼ型結晶（１０１）面のシェラー（Ｓｃｈｅｒｒｅｒ）の式から求めた結晶子径は１７．３ｎｍで、硫酸根（ＳＯ４）の含有量は３．５ｗｔ％であり、該二酸化チタン粉末（ａ）の粒子径は９９．９８重量％が４５μｍ以下であった。
【００３５】
実施例２＜ハニカム状排ガス処理触媒用二酸化チタン粉末の調製（ｂ）＞
実施例１と同様にして調製した洗浄ケーキを１１０℃で２０時間乾燥した後、これを４５９℃で５時間焼成して二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末を得た。該二酸化チタン粉末を粉砕して二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｂ）を調製した。該二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｂ）の粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピ−クハイトＸは１２１ｍｍで、基準試料に対するピーク強度比（Ｘ／Ｙ）は０．８０であった。
また、該二酸化チタン粉末（ｂ）は、アナターゼ型結晶（１０１）面のシェラー（Ｓｃｈｅｒｒｅｒ）の式から求めた結晶子径は１５．２ｎｍで、硫酸根（ＳＯ４）の含有量は３．７ｗｔ％であり、該二酸化チタン粉末（ｂ）の粒子径は９９．９８重量％が４５μｍ以下であった。
【００３６】
実施例３＜ハニカム状排ガス処理触媒用二酸化チタン粉末の調製（ｃ）＞
実施例１と同様にして調製した洗浄ケーキを１１０℃で２０時間乾燥した後、これを６０１℃で５時間焼成して二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末を得た。該二酸化チタン粉末を粉砕して二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｃ）を調製した。該二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｃ）の粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピ−クハイトＸは１７７ｍｍで、基準試料に対するピーク強度比（Ｘ／Ｙ）は１．１７であった。
また、該二酸化チタン粉末（ｃ）は、アナターゼ型結晶（１０１）面のシェラー（Ｓｃｈｅｒｒｅｒ）の式から求めた結晶子径は２１．２ｎｍで、硫酸根（ＳＯ４）の含有量は２．１ｗｔ％であり、該二酸化チタン粉末（ｃ）の粒子径は９９．９８重量％が４５μｍ以下であった。
【００３７】
比較例１＜ハニカム状排ガス処理触媒用二酸化チタン粉末の調製（ｄ）＞
実施例１と同様にして調製した洗浄ケーキを１１０℃で２０時間乾燥した後、これを３０８℃で５時間焼成して二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末を得た。該二酸化チタン粉末を粉砕して二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｄ）を調製した。該二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｄ）の粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピ−クハイトＸは６０ｍｍで、基準試料に対するピーク強度比（Ｘ／Ｙ）は０．４０であった。
また、該二酸化チタン粉末（ｄ）は、アナターゼ型結晶（１０１）面のシェラー（Ｓｃｈｅｒｒｅｒ）の式から求めた結晶子径は１０．２ｎｍで、硫酸根（ＳＯ４）の含有量は３．９ｗｔ％であり、該二酸化チタン粉末（ｄ）の粒子径は９９．９８重量％が４５μｍ以下であった。
【００３８】
比較例２＜ハニカム状排ガス処理触媒用二酸化チタン粉末の調製（ｅ）＞
実施例１と同様にして調製した洗浄ケーキを１１０℃で２０時間乾燥した後、これを６８５℃で５時間焼成して二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｅ）を調製した。該二酸化チタン粉末をさらに粉砕して二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｅ）を調製した。該二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｅ）の粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピ−クハイトＸは２１０ｍｍで、基準試料に対するピーク強度比（Ｘ／Ｙ）は１．３９であった。
また、該二酸化チタン粉末（ｅ）は、アナターゼ型結晶（１０１）面のシェラー（Ｓｃｈｅｒｒｅｒ）の式から求めた結晶子径は２４．５ｎｍで、硫酸根（ＳＯ４）の含有量は０．４ｗｔ％であり、該二酸化チタン粉末（ｅ）の粒子径は９９．９８重量％が４５μｍ以下であった。
【００３９】
比較例３＜ハニカム状排ガス処理触媒用二酸化チタン粉末の調製（ｆ）＞
硫酸法による二酸化チタンの製造工程より得られる硫酸チタン溶液を熱加水分解してメタチタン酸スラリーを得た。このメタチタン酸スラリーを二酸化チタンとして２５．０ｋｇ取り出し、これを１１０°Ｃで２０時間乾燥して、ＳＯ４が８．０ｗｔ％（Ｄｒｙ Ｂａｓｉｓ）、Ｎａ２Ｏが０．０３ｗｔ％（Ｄｒｙ Ｂａｓｉｓ）の乾燥品を得た。該乾燥品を５０９℃で５時間焼成して二酸化チタン粉末を得た。該二酸化チタン粉末を粉砕して二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｆ）を調製した。該二酸化チタンからなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｆ）の粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピ−クハイトＸは１１５ｍｍで、基準試料に対するピーク強度比（Ｘ／Ｙ）は０．７６であった。
また、該二酸化チタン粉末（ｆ）は、アナターゼ型結晶（１０１）面のシェラー（Ｓｃｈｅｒｒｅｒ）の式から求めた結晶子径は１４．７ｎｍで、硫酸根（ＳＯ４）の含有量は５．５ｗｔ％であり、該二酸化チタン粉末（ｆ）の粒子径は９９．９８重量％が４５μｍ以下であった。
【００４０】
実施例４＜ハニカム状排ガス処理触媒用二酸化チタンの調製（ｇ）＞
硫酸法による二酸化チタンの製造工程より得られる硫酸チタン溶液を熱加水分解してメタチタン酸スラリーを得た。このメタチタン酸スラリーを二酸化チタンとして２２．５ｋｇ取り出し、還流器付攪拌槽に仕込み、これにパラタングステン酸アンモニウム２．８２ｋｇを添加混合した後、１５重量％アンモニア水３０．５ｋｇを加えてｐＨを９．５に調整し、次いで、９５℃で１時間に亘り十分な攪拌を行いつつ加熱熟成した。その後、冷却して該スラリ−を取り出し、濾過、脱水、洗浄して、ＳＯ４が３．０ｗｔ％（Ｄｒｙ Ｂａｓｉｓ）、Ｎａ２Ｏが０．０３ｗｔ％（Ｄｒｙ Ｂａｓｉｓ）の洗浄ケーキを得た。該洗浄ケーキを１１０℃で２０時間乾燥した後、これを５５０℃で５時間焼成して二酸化チタンと酸化タングステンの複合酸化物（ＴｉＯ２−ＷＯ３）からなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｇ）を調製した。該ＴｉＯ２−ＷＯ３複合酸化物粉末をさらに粉砕してハニカム状排ガス処理用二酸化チタン粉末（ｇ）を調製した。ＴｉＯ２−ＷＯ３からなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｇ）のＴｉＯ２／ＷＯ３重量比は９０／１０で、粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピークハイトＸは１４０ｍｍで、基準試料に対するピーク強度比（Ｘ／Ｙ）は０．９３であった。
また、該二酸化チタン粉末（ｇ）は、アナターゼ型結晶（１０１）面のシェラー（Ｓｃｈｅｒｒｅｒ）の式から求めた結晶子径は１６．３ｎｍで、硫酸根（ＳＯ４）の含有量は１．７ｗｔ％であり、該二酸化チタン粉末（ｇ）の粒子径は９９．９８重量％が４５μｍ以下であった。
【００４１】
比較例４＜ハニカム状排ガス処理触媒用二酸化チタンの調製（ｈ）＞
硫酸法による二酸化チタンの製造工程より得られる硫酸チタン溶液を熱加水分解してメタチタン酸スラリーを得た。このメタチタン酸スラリーを二酸化チタンとして２２．５ｋｇ取り出し、還流器付攪拌槽に仕込み、これにパラタングステン酸アンモニウム２．８２ｋｇを添加混合した後、１５重量％アンモニア水６１．０ｋｇを加えてｐＨを９．５に調整し、次いで、９５℃で１時間に亘り十分な攪拌を行いつつ加熱熟成した。その後、冷却して該スラリ−を取り出した後、濾過、脱水、１５重量％のアンモニア水による洗浄の工程を３回繰り返して、ＳＯ４が０．３ｗｔ％（Ｄｒｙ Ｂａｓｉｓ）、Ｎａ２Ｏが０．０１ｗｔ％（ＤｒｙＢａｓｉｓ）の洗浄ケーキを得た。該洗浄ケーキを１１０℃で２０時間乾燥した後、これを５５０℃で５時間焼成し、さらに粉砕して二酸化チタンと酸化タングステンの複合酸化物（ＴｉＯ２−ＷＯ３）からなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｈ）を調製した。ＴｉＯ２−ＷＯ３からなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｈ）のＴｉＯ２／ＷＯ３重量比は９０／１０で、粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピークハイトＸは１５２ｍｍで、基準試料に対するピーク強度比（Ｘ／Ｙ）は１．０１であった。
また、該二酸化チタン粉末（ｈ）は、アナターゼ型結晶（１０１）面のシェラー（Ｓｃｈｅｒｒｅｒ）の式から求めた結晶子径は１７．７ｎｍで、硫酸根（ＳＯ４）の含有量は０．２ｗｔ％であり、該二酸化チタン粉末（ｈ）の粒子径は９９．９８重量％が４５μｍ以下であった。
【００４２】
実施例５＜ハニカム状排ガス処理触媒用二酸化チタン粉末の調製（ｉ）＞
硫酸法による二酸化チタンの製造工程より得られる硫酸チタン溶液を熱加水分解してメタチタン酸スラリーを得た。このメタチタン酸スラリーを二酸化チタンとして２１．２５ｋｇ取り出し、還流器付攪拌槽に仕込み、これにシリカゾル〔ＳｉＯ２濃度２０ｗｔ％、商品名“カタロイドＳ−２０Ｌ”触媒化成工業（株）製〕６．２５ｋｇを添加混合した後、１５重量％アンモニア水３０．５ｋｇを加えてｐＨを９．５に調整した後、９５℃で１時間に亘り十分な攪拌を行いつつ加熱熟成した。次いで、パラタングステン酸アンモニウム２．８２ｋｇを添加し、更に、９５℃で１時間加熱熟成を行った。その後、冷却して該スラリーを取り出し、濾過、脱水、洗浄して、ＳＯ４が３．５ｗｔ％（Ｄｒｙ Ｂａｓｉｓ）、Ｎａ２Ｏが０．０３ｗｔ％（Ｄｒｙ Ｂａｓｉｓ）の洗浄ケーキを得た。該洗浄ケーキを１１０℃で２０時間乾燥した後、これを５７８℃で５時間焼成し、さらに粉砕して二酸化チタンとシリカと酸化タングステンとの複合酸化物（ＴｉＯ２−ＳｉＯ２−ＷＯ３）からなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｉ）を調製した。ＴｉＯ２−ＳｉＯ２−ＷＯ３からなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｉ）のＴｉＯ２／ＳｉＯ２／ＷＯ３重量比は８５／５／１０で、粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピ−クハイトＸは９５ｍｍで、基準試料に対するピーク強度比（Ｘ／Ｙ）は０．６３であった。
また、該二酸化チタン粉末（ｉ）は、アナターゼ型結晶（１０１）面のシェラー（Ｓｃｈｅｒｒｅｒ）の式から求めた結晶子径は１３．１ｎｍで、硫酸根（ＳＯ４）の含有量は１．８ｗｔ％であり、該二酸化チタン粉末（ｉ）の粒子径は９９．９８重量％が４５μｍ以下であった。
【００４３】
比較例５＜ハニカム状排ガス処理触媒用二酸化チタン粉末の調製（ｊ）＞
実施例５と同様にして調製した洗浄ケーキを１１０℃で２０時間乾燥した後、これを５０３℃で５時間焼成し、さらに粉砕して二酸化チタンとシリカと酸化タングステンとの複合酸化物（ＴｉＯ２−ＳｉＯ２−ＷＯ３）からなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｊ）を調製した。ＴｉＯ２−ＳｉＯ２−ＷＯ３からなるハニカム状排ガス処理触媒用二酸化チタン粉末（ｊ）のＴｉＯ２／ＳｉＯ２／ＷＯ３重量比は８５／５／１０で、粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピ−クハイトＸは６５ｍｍで、基準試料に対するピーク強度比（Ｘ／Ｙ）は０．４３であった。
また、該二酸化チタン粉末（ｊ）は、アナターゼ型結晶（１０１）面のシェラー（Ｓｃｈｅｒｒｅｒ）の式から求めた結晶子径は９．８ｎｍで、硫酸根（ＳＯ４）の含有量は３．１ｗｔ％であり、該二酸化チタン粉末（ｊ）の粒子径は９９．９８重量％が４５μｍ以下であった。
【００４４】
実施例６＜ハニカム状排ガス処理触媒の調製（ａ−１）＞
実施例１のハニカム状排ガス処理触媒用二酸化チタン粉末（ａ）２１．２５ｋｇに、メタバナジン酸アンモニウム１．６１ｋｇをモノエタノールアミン０．８１ｋｇに溶解した溶液に加え、次いでアンモニア水と水を加えこの混合スラリーのｐＨを９とし、さらにグラスファイバー（ＧＦ）1．２５ｋｇ、酸性白土（粘土）１．２５ｋｇおよびポリエチレンオキサイド０．５ｋｇを加えてニーダーにて加熱、混練捏和して押出成形に適した捏和物を調製した。次いで該捏和物を真空押出成形機で、ハニカム外径８０ｍｍ□（四角形状を意味する）、目開き（貫通孔径）２．５５ｍｍ（一辺の孔径が２．５５ｍｍの四角形状の貫通孔径）、隔壁厚０．４５ｍｍ、開口率６８．７％、長さ３００ｍｍのハニカム状に押出し成形し、成型物を６０℃で２４ｈｒ乾燥後、５００℃で３ｈｒ焼成して、重量比でＴｉＯ２粉末（ａ）／Ｖ２Ｏ５／ＧＦ／粘土が８５／５／５／５の組成をもつハニカム状排ガス処理触媒（ａ−１）を調製した。触媒（ａ−１）の性状を表１に示す。
【００４５】
実施例７＜ハニカム状排ガス処理触媒の調製（ｂ−１）＞
実施例６において、実施例２のハニカム状排ガス処理触媒用二酸化チタン粉末（ｂ）を使用した以外は、実施例６と全く同様にして、重量比でＴｉＯ２粉末（ｂ）／Ｖ２Ｏ５／ＧＦ／粘土が８５／５／５／５の組成をもつハニカム状排ガス処理触媒（ｂ−１）を調製した。触媒（ｂ−１）の性状を表１に示す。
【００４６】
実施例８＜ハニカム状排ガス処理触媒の調製（ｃ−１）＞
実施例６において、実施例３のハニカム状排ガス処理触媒用二酸化チタン粉末（ｃ）を使用した以外は、実施例６と全く同様にして、重量比でＴｉＯ２粉末（ｃ）／Ｖ２Ｏ５／ＧＦ／粘土が８５／５／５／５の組成をもつハニカム状排ガス処理触媒（ｃ−１）を調製した。触媒（ｃ−１）の性状を表１に示す。
【００４７】
比較例６＜ハニカム状排ガス処理触媒の調製（ｄ−１）＞
実施例６において、比較例１のハニカム状排ガス処理触媒用二酸化チタン粉末（ｄ）を使用した以外は、実施例６と全く同様にしてニーダーにて混練捏和して押出成形に適した捏和物を調製した。次いで該捏和物を真空押出成形機で、ハニカム外径８０ｍｍ□、目開き２．５５ｍｍ、隔壁厚０．４５ｍｍ、開口率６８．７％、長さ３００ｍｍのハニカム状に押出成形したところ、捏和物が真空押出成形機の中で脱水現象を起こし、ハニカム状に押出成形することが出来ず、ハニカム状排ガス処理触媒（ｄ−１）のサンプルを採取することが出来なかった。なお、該触媒（ｄ−１）の組成は、ＴｉＯ２粉末（ｄ）／Ｖ２Ｏ５／ＧＦ／粘土が８５／５／５／５重量比である。触媒（ｄ−１）の性状を表１に示す。
【００４８】
比較例７＜ハニカム状排ガス処理触媒の調製（ｅ−１）＞
実施例６において、比較例２のハニカム状排ガス処理触媒用二酸化チタン粉末（ｅ）を使用した以外は、実施例６と全く同様にして重量比でＴｉＯ２粉末（ｅ）／Ｖ２Ｏ５／ＧＦ／粘土が８５／５／５／５の組成をもつハニカム状排ガス処理触媒（ｅ−１）を調製した。触媒（ｅ−１）の性状を表１に示す。
【００４９】
比較例８＜ハニカム状排ガス処理触媒の調製（ｆ−１）＞
実施例６において、比較例３のハニカム状排ガス処理触媒用二酸化チタン粉末（ｆ）を使用した以外は、実施例６と全く同様にしてニーダーにて混練捏和して押出成形に適した捏和物を調製した。次いで該捏和物を真空押出成形機で、ハニカム外径８０ｍｍ□、目開き２．５５ｍｍ、隔壁厚０．４５ｍｍ、開口率６８．７％、長さ３００ｍｍのハニカム状に押出成形したところ、捏和物が真空押出成形機の中で脱水現象を起こし、ハニカム状に押出成形することが出来ず、ハニカム状排ガス処理触媒（ｆ−１）のサンプルを採取することが出来なかった。なお、該触媒（ｆ−１）の組成は、ＴｉＯ２粉末（ｆ）／Ｖ２Ｏ５／ＧＦ／粘土が８５／５／５／５重量比である。触媒（ｆ−１）の性状を表１に示す。
【００５０】
実施例９＜ハニカム状排ガス処理触媒の調製（ｇ−１）＞
実施例６において、実施例４のハニカム状排ガス処理触媒用二酸化チタン粉末（ｇ）を使用した以外は、実施例６と全く同様にして重量比でＴｉＯ２−ＷＯ３粉末（ｇ）／Ｖ２Ｏ５／ＧＦ／粘土が８５／５／５／５の組成をもつハニカム状排ガス処理触媒（ｇ−１）を調製した。触媒（ｇ−１）の性状を表１に示す。
【００５１】
比較例９＜ハニカム状排ガス処理触媒の調製（ｈ−１）＞
実施例６において、比較例４のハニカム状排ガス処理触媒用二酸化チタン粉末（ｈ）を使用した以外は、実施例６と全く同様にして重量比でＴｉＯ２−ＷＯ３粉末（ｈ）／Ｖ２Ｏ５／ＧＦ／粘土が８５／５／５／５の組成をもつハニカム状排ガス処理触媒（ｈ−１）を調製した。触媒（ｈ−１）の性状を表１に示す。
【００５２】
実施例１０＜ハニカム状排ガス処理触媒の調製（ｇｉ−１）＞
実施例４のハニカム状排ガス処理触媒用二酸化チタン粉末（ｇ）１６．２５ｋｇと実施例５のハニカム状排ガス処理触媒用二酸化チタン粉末（ｉ）５．０ｋｇの混合物に、メタバナジン酸アンモニウム１．６１ｋｇをモノエタノールアミン０．８１ｋｇに溶解して得た溶液を加え、次いでアンモニア水と水を加えこの混合スラリーのｐＨを９とし、さらにグラスファイバー１．２５ｋｇ、酸性白土１．２５ｋｇおよびポリエチレンオキサイド０．５ｋｇを加えてニーダーにて加熱、混練捏和して押出成形に適した捏和物を調製した。次いで該捏和物を真空押出成形機で、ハニカム外径８０ｍｍ□、目開き２．５５ｍｍ、隔壁厚０．４５ｍｍ、開口率６８．７％、長さ３００ｍｍのハニカム状に押出成形し、成型物を６０℃で２４ｈｒ乾燥後、５００℃で３ｈｒ焼成して、重量比でＴｉＯ２−ＷＯ３粉末（ｇ）／ＴｉＯ２−ＳｉＯ２−ＷＯ３粉末（ｉ）／Ｖ２Ｏ５／ＧＦ／粘土が６５／２０／５／５／５の組成をもつハニカム状排ガス処理触媒（ｇｉ−１）を調製した。触媒（ｇｉ−１）の性状を表１に示す。
【００５３】
実施例１１＜ハニカム状排ガス処理触媒の調製（ｇｊ−１）＞
実施例１０において、実施例５のハニカム状排ガス処理触媒用二酸化チタン粉末（ｉ）の代わりに比較例５のハニカム状排ガス処理触媒用二酸化チタン粉末（ｊ）５．０ｋｇを使用した以外は、実施例１０と全く同様にして、重量比でＴｉＯ２−ＷＯ３粉末（ｇ）／ＴｉＯ２−ＳｉＯ２−ＷＯ３粉末（ｊ）／Ｖ２Ｏ５／ＧＦ／粘土が６５／２０／５／５／５の組成をもつハニカム状排ガス処理触媒（ｇｊ−１）を調製した。この触媒は、比較例５の二酸化チタン粉末（ｊ）を含有するが、実施例４の二酸化チタン粉末（ｇ）を６０重量％以上含有しているので成形性は良好であった。触媒（ｇｊ−１）の性状を表１に示す。
【００５４】
比較例１０＜ハニカム状排ガス処理触媒の調製（ｊｇ−１）＞
実施例１０において、比較例５のハニカム状排ガス処理触媒用二酸化チタン粉末（ｊ）１６．２５ｋｇと実施例４のハニカム状排ガス処理触媒用二酸化チタン粉末（ｇ）５．０ｋｇの混合物を使用した以外は、実施例１０と全く同様にしてニーダーで加熱、混練捏和して押出成形に適した捏和物を調製した。次いで該捏和物を真空押出成形機で、ハニカム外径８０ｍｍ□、目開き２．５５ｍｍ、隔壁厚０．４５ｍｍ、開口率６８．７％、長さ３００ｍｍのハニカム状に押出成形したところ、捏和物が真空押出成形機の中で脱水現象を起こし、ハニカム状に押出成形することが困難で、ハニカム状排ガス処理触媒（ｊｇ−１）のサンプルを採取することが出来なかった。なお、該触媒（ｊｇ−１）の組成は、重量比でＴｉＯ２−ＷＯ３粉末（ｇ）／ＴｉＯ２−ＳｉＯ２−ＷＯ３粉末（ｊ）／Ｖ２Ｏ５／ＧＦ／粘土が２０／６５／５／５／５である。触媒（ｊｇ−１）の性状を表１に示す。
【００５５】
実施例１２＜窒素酸化物除去性能試験＞
実施例６〜１１の触媒（ａ−１）、（ｂ−１）、（ｃ−１）、（ｇ−１）、（ｇｉ―１）、（ｇｊ−１）および比較例６〜１０の触媒（ｄ−１）、（ｅ−１）、（ｆ−１）、（ｈ−１）、（ｊｇ―１）を使用して窒素酸化物除去性能試験を行った。
各ハニカム触媒から２５０ｍｍの長さで貫通孔の数を８×８目（１目は１貫通孔を表わす）に切り出した試験試料を流通式反応器に充填し、下記条件で脱硝率を測定した。脱硝率は触媒接触前後のガス中の窒素酸化物（ＮＯｘ）の濃度をケミルミ式窒素酸化物分析計にて測定し次式により求めた。
【数７】
【００５６】
【表１】
表１から明らかな様に、同組成である実施例６〜８の触媒（ａ−１）、（ｂ−１）、（ｃ−１）および比較例６〜８の触媒（ｄ−１）、（ｅ−１）、（ｆ−１）を比較した場合、一般に使用した二酸化チタン粉末原料の粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面の基準試料に対するピーク強度比が低い実施例の触媒（ａ−１）、（ｂ−１）、（ｃ−１）は脱硝性能が高く、二酸化チタン粉末の基準試料に対するピーク強度比が１．２０を越える比較例７の（ｅ−１）触媒は性能低下が顕著に観られる。また、二酸化チタン粉末の基準試料に対するピーク強度比が０．５９を下回る比較例の（ｄ−１）触媒に関しては成形が極めて困難でハニカム状サンプルを採取できなかった。更に、二酸化チタン粉末の基準試料に対するピーク強度比が式（１）の条件を満たしているが、二酸化チタン粉末中に硫酸根（ＳＯ４）を多量に含有する比較例８の（ｆ−１）触媒は成形性が悪くハニカム状サンプルを採取することができなかった。なお、ハニカム構造体の隔壁の厚さが薄いハニカム状排ガス処理触媒は、ダストなどを含まない排ガスを対象とするものであり、この場合は摩耗率は問題とならない。
【００５８】
触媒（ｇｉ−１）および（ｇｊ−１）は主原料として原料（ｇ）を６５重量％含有していることは同じであるが、副原料である二酸化チタン粉末の基準試料に対するピーク強度比が異なる。この場合、二酸化チタン粉末の基準試料に対するピーク強度比の低い原料（ｊ）を用いた触媒（ｇｊ−１）の方が、高い脱硝性能を有することが分かる。ここで、二酸化チタン粉末（ｊ）は基準試料に対するピーク強度比が０．４３であるため、成形性が悪化することが懸念されるが、基準試料に対するピーク強度比が０．９３の二酸化チタン粉末（ｇ）を６０重量％以上含有しているため、成形性には問題なかった。しかしながら、二酸化チタン粉末（ｊ）が６５％で二酸化チタン粉末（ｇ）が２０重量％である触媒（ｊｇ−１）は、成形性が悪く、ハニカム状サンプルを採取することは不可能であった。
【００５９】
実施例１３＜ハニカム状排ガス処理触媒の調製（ａ−２）＞
実施例１３、１４および比較例１１は、反応ガス中にハニカム構造体の隔壁を摩耗させる砂を混在させることにより、隔壁の摩耗率を測定している。そのため隔壁の当初の厚みも、実施例１〜１２のものに較べて厚くなっている。
実施例１のハニカム状排ガス処理触媒用二酸化チタン粉末（ａ）２３．５０ｋｇに、メタバナジン酸アンモニウム０．３２ｋｇをモノエタノールアミン０．１６ｋｇに溶解して得た溶液を加え、次いでアンモニア水と水を加えこの混合スラリーのｐＨを９とし、さらにガラスファイバー（ＧＦ）１．２５ｋｇとポリエチレンオキサイド０．５ｋｇを加えてニーダーで加熱、混練捏和して押出成形に適した捏和物を調製した。次いで該捏和物を真空押出成形機で、ハニカム外径８２ｍｍ□、目開き６．７０ｍｍ、隔壁厚１．２０ｍｍ、開口率６６．８％、長さ３００ｍｍのハニカム状に押出成形し、成型物を６０℃で２４ｈｒ乾燥後、６００℃で３ｈｒ焼成して、ＴｉＯ２／Ｖ２Ｏ５／ＧＦが９４／１／５重量％の組成をもつハニカム状排ガス処理触媒（ａ−２）を調製した。触媒（ａ−２）の性状を表２に示す。
【００６０】
比較例１１＜ハニカム状排ガス処理触媒の調製（ｄ−２）＞
実施例１３において、比較例１のハニカム状排ガス処理触媒用二酸化チタン粉末（ｄ）を使用した以外は、実施例１３と全く同様にしてＴｉＯ２／Ｖ２Ｏ５／ＧＦが９４／１／５重量％の組成および形状をもつハニカム状排ガス処理触媒（ｄ−２）を調製した。該ハニカム状触媒は、ハニカム外径８２ｍｍ□、目開き６．７０ｍｍ、隔壁厚１．２０ｍｍとハニカムの目開きが大きく、隔壁厚が厚いためなんとかハニカム状に成形することができた。触媒（ｄ−２）の性状を表２に示す。
【００６１】
実施例１４＜ハニカム状排ガス処理触媒の調製（ａｉ−２）＞
実施例１３において、実施例１のハニカム状排ガス処理触媒用二酸化チタン粉末（ａ）１７．２５ｋｇと実施例５のハニカム状排ガス処理触媒用二酸化チタン粉末（ｉ）６．２５ｋｇの混合物を使用した以外は、実施例１３と全く同様にして、ＴｉＯ２／ＴｉＯ２−ＷＯ３−ＳｉＯ２／Ｖ２Ｏ５／ＧＦ＝６９／２５／１／５重量％の組成もつ触媒（ａｉ−２）を調製した。触媒（ａｉ−２）の性状を表２に示す。
【００６２】
実施例１５
実施例１３、１４の触媒（ａ−２）、（ａｉ−２）および比較例１１の触媒（ｄ−２）を使用して窒素酸化物除去性能試験および触媒の摩耗試験を行った。
＜窒素酸化物除去性能試験＞
各ハニカム触媒から３００ｍｍの長さで３×３目に切り出した試験試料を流通式反応器に充填し、下記条件で脱硝率を測定した。脱硝率は触媒接触前後のガス中の窒素酸化物（ＮＯｘ）の濃度をケミルミ式窒素酸化物分析計にて測定し次式により求めた。
【数８】
各ハニカム触媒から１００ｍｍの長さで９×９目に切り出した試験試料を流通式反応器に充填し、砂を含むガスを下記条件で流して触媒の減少重量から摩耗率を測定した。なお、通砂量はサイクロンで捕集して測定終了後、重量を測定して求める。
【表２】
表２より、主原料を二酸化チタン粉末の基準試料に対するピーク強度比が０．４０である二酸化チタン粉末（ｄ）を用いた触媒（ｄ−２）は、脱硝性能は高いが摩耗率が極めて高い。比較例１１の触媒（ｄ−２）は石炭焚きボイラ排ガスなどのダストを含む排ガス処理用触媒としては使用中に排ガス中のダストなどにより触媒が摩耗して減少するので不適当である。一方、原料二酸化チタン粉末の基準試料に対するピーク強度比が０．９３である二酸化チタン粉末（ａ）を用いた触媒（ａ−２）は摩耗率が極めて低く、摩耗強度が強い。また、二酸化チタン粉末原料の一部を原料（ｉ）に置き換えた触媒（ａｉ−２）は、適度な摩耗強度を有しつつも、（ａ−２）よりもさらに性能が向上しているのが分かる。
【００６５】
【発明の効果】
本発明の二酸化チタンおよび／またはチタン複合酸化物からなるハニカム状排ガス処理触媒用二酸化チタン粉末は、粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面のピーク強度比Ｘ／Ｙが式（１）において０．５９〜１．２０の範囲にあり、かつ、結晶子径が８〜２２ｎｍの範囲にあり、該二酸化チタン粉末中の硫酸根（ＳＯ４）含有量が０．３〜５．０重量％の範囲にあるので、ハニカム状触媒に押出成形が容易である。本発明の原料を６０重量％以上使用したハニカム状排ガス処理触媒は高い窒素酸化物除去性能を有し、かつ、多孔薄壁のハニカム状触媒が容易に製造できる。そのため、必要な触媒量を少なくすることができ、排ガス処理触媒装置をコンパクトにすることが可能である。さらには該ハニカム状排ガス処理触媒は、耐摩耗強度が高いため触媒の寿命も長くなる。
【図面の簡単な説明】
【図１】本文記載の測定装置と測定条件に基づいて画かれたＸ線回折図の縮小図面であり、実物のピークハイトは１５１ｍｍである。
【図２】本発明の１例を示すハニカム構造体を押出方向に直角に切断したときの断面図である。[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a titanium dioxide powder for a honeycomb-shaped exhaust gas treatment catalyst and a honeycomb-like exhaust gas treatment catalyst using the titanium dioxide powder, and more specifically, includes heavy oil, a coal fired boiler, a thermal power plant, a steel mill, and the like. Titanium dioxide that efficiently removes nitrogen oxides and organic halogen compounds, ammonia, carbonyl sulfide, volatile organic compounds, etc. contained in exhaust gas discharged from combustion furnaces and garbage incinerators at various factories. The present invention relates to a titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst comprising titanium oxide and / or a titanium composite oxide, and a honeycomb-shaped exhaust gas treatment catalyst using the titanium dioxide powder.
[0002]
[Prior art]
Various harmful substances such as nitrogen oxides and organic halogen compounds are contained in the combustion exhaust gas emitted from combustion furnaces of various factories such as thermal power plants and ironworks, incinerators that process municipal waste, industrial waste, etc. Among them, nitrogen oxide is a causative substance of photochemical smog, and removal of organic halogen compounds such as dioxin is particularly important since it is highly toxic.
[0003]
Various methods are known for removing nitrogen oxides from combustion exhaust gas. However, a selective ammonia reduction system (SCR) using a catalyst is the mainstream, and the catalyst used for this is a titanium oxide carrier and tungsten oxide. Catalysts carrying active components such as vanadium oxide are the mainstream. For example, Patent Document 1 discloses a method for producing a denitration catalyst comprising titania having an anatase structure as a main component and supporting one or more of a vanadium compound or a molybdenum compound and a tungsten compound as an active component. A part of anatase in the carrier is rutiled, and rutile particles are dispersed in anatase having a high specific surface area, whereby the integrated intensity ratio of rutile / anatase peak by powder X-ray diffraction method is 0.001 to 0.05. And the specific surface area of the catalyst is 30 m. 2 It is described that a denitration catalyst having a high denitration activity can be obtained by calcining so as to be at least 1 g / g.
[0004]
Patent Document 2 discloses a porous titania exhibiting excellent catalytic activity in applications such as denitration, which has an anatase type crystal structure, a crystallite diameter of 3 nm to 10 nm, and an anatase crystallization rate of 60% or more. , BET specific surface area is 10m 2 / G or more, total pore volume is 0.05 cm 3 / G or more and a pore volume having a pore radius of 1 nm or more is 0.02 cm 3 Disclosed is a porous titania characterized by being / g or more.
[0005]
Patent Document 3 proposes an exhaust gas treatment catalyst and an exhaust gas treatment method. In this publication, in an exhaust gas treatment catalyst containing amorphous phase titanium oxide, 2θ = 24.7 of powder X-ray diffraction is disclosed. The intensity of the peak showing anatase crystals existing between 0 ° and 25.7 ° is 5% by weight V as a reference substance. 2 O 5 -95 wt% TiO 2 It is characterized in that it is 75% or less of the intensity of the peak showing anatase crystal existing between 2θ = 24.7 ° to 25.7 ° of powder X-ray diffraction of (Titanium oxide DT-51 manufactured by Millennium). An exhaust gas treatment catalyst has been disclosed, and the smaller the intensity of the peak showing anatase crystals, the smaller the proportion of anatase-type titanium oxide and the greater the proportion of amorphous-phase titanium oxide, such as dioxins It describes that the decomposition activity and denitration activity of toxic organic halogen compounds are high.
[0006]
As described above, in a conventional denitration catalyst in which an active component such as tungsten oxide or vanadium oxide is supported on a titanium oxide carrier, the denitration activity is higher when the crystallinity of the anatase-type titanium dioxide crystal is higher. There is a theory that the lower the crystallinity, the higher the activity, and the relationship between the crystallinity of anatase-type titanium dioxide crystals and the denitration activity has not been clarified.
[0007]
On the other hand, the shape of the exhaust gas treatment catalyst includes a honeycomb shape, a cylindrical shape, a spherical shape, a plate shape, etc., but as a catalyst used industrially, a honeycomb shape in which dust is not easily accumulated and clogged in a catalyst layer is suitable. Yes. As a method for producing a honeycomb-shaped catalyst, (a) a method in which a carrier component is extruded into a honeycomb shape and then impregnated / supported with an active component, or a carrier component and an active component are kneaded together with a molding aid or the like. A method of extruding into a honeycomb shape, (b) a method of impregnating and supporting a carrier component and an active component on a honeycomb-shaped base material are known. The catalyst of the method (a) is said to be a solid type catalyst and has a high denitration activity, and is currently mainstream.
[0008]
Conventionally, the amount of boiler exhaust gas from power plants has been 100,000 to 2,000,000 Nm per unit. 3 The amount of catalyst used for treating the exhaust gas is increased because the amount is very large as / hr. In order to solve this problem, in order to increase the geometric surface area per unit volume of the honeycomb-shaped catalyst and increase the removal efficiency of nitrogen oxides and the like in the catalyst for gas burning with less dust in the exhaust gas, the honeycomb structure Catalysts with a reduced partition wall thickness and an increased number of through holes have been required. However, the honeycomb-shaped exhaust gas treatment catalyst raw material mainly composed of titanium oxide and / or titanium composite oxide powder has poor moldability, and the honeycomb structure having a small partition wall thickness and an increased number of through holes is extruded. It was difficult to do.
In addition, hard glassy dust is 10 to 25 g / Nm in coal-fired boiler exhaust gas. 3 Furthermore, since the flow rate of exhaust gas in the denitration reactor is extremely fast, there is a problem that the reduction due to catalyst wear increases, and there is a need for a honeycomb exhaust gas treatment catalyst having high wear resistance. It was.
[0009]
[Patent Document 1]
JP-A-8-281103
[Patent Document 2]
JP 2001-114519 A
[Patent Document 3]
JP 2001-113169 A
[0010]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described circumstances, and an object thereof is titanium dioxide and / or a titanium composite having excellent extrudability of a honeycomb structure in which the honeycomb partition wall thickness is thin and the number of through holes is increased. An object of the present invention is to provide a honeycomb-shaped exhaust gas treatment catalyst titanium dioxide powder comprising an oxide powder, a catalyst having high denitration activity using the titanium dioxide powder, and a catalyst having high decomposition activity of an organic halogen compound. Another object of the present invention is to provide a honeycomb-shaped exhaust gas treatment catalyst having a high wear resistance when used in coal-fired boiler exhaust gas treatment containing a large amount of dust.
[0011]
[Means for Solving the Problems]
As a result of various studies, the present inventors have found that anatase, which is a raw material of a honeycomb-shaped exhaust gas treatment catalyst, in an exhaust gas treatment catalyst such as a denitration catalyst in which an active component such as tungsten oxide or vanadium oxide is supported on a titanium dioxide support. The lower the crystallinity of the type titanium dioxide, the higher the nitrogen oxide removal performance and the like. On the other hand, the extrudability of the honeycomb structure deteriorates when the crystallinity of the anatase type titanium dioxide is low. Finding that the higher the crystallinity of titanium, the better the extrudability, and that there is an optimum range of anatase-type titanium dioxide crystallinity from both the denitration active surface and the extrudability surface of the honeycomb structure, Furthermore, the sulfate radical (SO) contained in the raw material titanium dioxide. 4 ), The crystallite size of titanium dioxide, and the particle size distribution of the titanium dioxide powder have been found to affect the extrudability and wear resistance of the catalyst, and the present invention has been completed.
[0012]
The first aspect of the present invention is a honeycomb-shaped exhaust gas treatment catalyst dioxide comprising titanium dioxide and / or titanium composite oxide (the titanium composite oxide in the present invention refers to titanium dioxide containing an inorganic oxide other than titanium). Titanium powder
(A) The peak intensity ratio of the (101) plane titanium dioxide powder to the reference sample of the anatase-type titanium dioxide crystal measured by powder X-ray diffraction is expressed by the following formula (1)
[Expression 2]
0.59 ≦ X / Y ≦ 1.20 (1)
[Where Y is 0.300 g of pure anatase type titanium dioxide (Kanto Chemical Co., Ltd .: reagent deer grade 1) and 1.700 g of pure nickel oxide (manufactured by Wako Pure Chemicals: reagent grade 1) are ground and mixed in an agate mortar. Is the peak intensity (mm) of the (101) plane of the anatase-type titanium dioxide crystal of the reference sample, and X is the peak intensity of the (101) plane of the anatase-type titanium dioxide crystal of the titanium dioxide powder for honeycomb exhaust gas treatment catalyst ( mm)]
In the range represented by
(B) The crystallite diameter of the anatase crystal (101) plane is in the range of 8 to 22 nm.
(C) Sulfate radical (SO 4 ) In the range of 0.3 to 5.0% by weight,
The present invention relates to a titanium dioxide powder for a honeycomb-shaped exhaust gas treatment catalyst characterized by having the following properties:
2. The honeycomb-shaped exhaust gas according to claim 1, wherein the titanium composite oxide is a composite oxide of titanium and at least one element selected from silicon, tungsten, molybdenum, and zirconium. The present invention relates to titanium dioxide powder for treatment catalyst.
A third aspect of the present invention relates to the titanium dioxide powder for a honeycomb-shaped exhaust gas treatment catalyst according to claim 1 or 2, wherein the titanium dioxide powder has a particle size of 99.9 wt% or more and 45 µm or less.
A fourth aspect of the present invention relates to a honeycomb-shaped exhaust gas treatment catalyst comprising 60% by weight or more of the titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst according to claim 1, 2 or 3.
The fifth of the present invention relates to the honeycomb-shaped exhaust gas treatment catalyst according to claim 4, wherein the honeycomb-shaped exhaust gas treatment catalyst is a honeycomb structure having the following shapes (i) to (v).
(I) the outer diameter of the honeycomb is 30 to 300 mm,
(Ii) The honeycomb has a length of 100 to 3000 mm,
(Iii) 1 to 15 mm of through-holes in the honeycomb,
(Iv) The partition wall thickness of the honeycomb is 0.1 to 2 mm,
(V) The honeycomb aperture ratio is 60 to 85%.
The sixth aspect of the present invention relates to the honeycomb-shaped exhaust gas treatment catalyst according to claim 4 or 5, wherein the honeycomb-shaped exhaust gas treatment catalyst is a nitrogen oxide removing catalyst.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail.
[0014]
Titanium dioxide (TiO2) for honeycomb-shaped exhaust gas treatment catalyst in the present invention 2 ) Or titanium composite oxide powder has an anatase type crystal structure, and in particular, the titanium composite oxide is, for example, silicon (Si), zirconium other than titanium dioxide powder for honeycomb exhaust gas treatment catalyst. (Zr), tungsten (W), molybdenum (Mo), vanadium (V), manganese (Mn), copper (Cu), tin (Sn), barium (Ba), cerium (Ce) and other titanium (hereinafter referred to as titanium) ) Is a compound comprising at least one inorganic oxide composed of an element other than) and a compound composed of the inorganic oxide or a mixture thereof, and the titanium dioxide in the composite oxide has an anatase type crystal structure. In particular, titanium dioxide and silica (TiO 2 -SiO 2 ), Titanium dioxide and tungsten oxide (TiO 2 -WO 3 ), Titanium dioxide and molybdenum oxide (TiO) 2 -MoO 3 ), Titanium dioxide and zirconia (TiO) 2 -ZrO 2 ) So-called binary complex oxides, as well as titanium dioxide, tungsten oxide and silica (TiO 2 -WO 3 -SiO 2 ), Titanium dioxide and molybdenum oxide and silica (TiO 2 -MoO 3 -SiO 2 ) Ternary complex oxide is TiO 2 And SiO 2 , WO 3 , MoO 3 Has a highly dispersed structure and progress of crystallization by heating and baking, or rutile TiO 2 This is preferable because it has the property of suppressing the transition to the.
The content of inorganic oxides other than titanium is preferably less than the amount of titanium dioxide, and is desirably in the range of 0.5 to 40% by weight. If the content of inorganic oxides other than titanium is larger than the amount of titanium dioxide, an excellent effect as a titanium oxide carrier of an exhaust gas treatment catalyst, particularly a nitrogen oxide removal catalyst may not be obtained.
[0015]
In general, titanium dioxide and / or titanium composite oxide with high peak strength has agglomerated secondary particles of titanium dioxide when a mechanical load is applied by kneading under wet conditions with a kneader or the like in the kneading stage during extrusion molding. Since it is peptized and exhibits appropriate plasticity and fluidity, it is easy to be extruded. Further, in the peptization of the titanium dioxide secondary particles, since the particle gap is filled with the titanium dioxide primary particles, the mechanical strength of the formed honeycomb catalyst becomes extremely high.
However, in the peptization of titanium dioxide secondary particles, the pore volume is reduced because the particle gaps are filled with the titanium dioxide primary particles, so the gas diffusion efficiency in the pores is reduced and the nitrogen oxide removal performance is reduced. To do. Furthermore, titanium dioxide and / or titanium composite oxide having a high peak intensity has a large crystallite size and a reduced specific surface area due to progress of crystallization. 2 O 5 Agglomeration of active metals such as the above occurs, resulting in a decrease in nitrogen oxide removal performance and the like.
[0016]
On the other hand, titanium dioxide and / or titanium composite oxide with low peak strength has a phenomenon that the kneaded product is dehydrated and solidified at the stage of extrusion molding, resulting in poor fluidity. Become.
However, titanium dioxide and / or titanium composite oxide having a low peak strength is used for the peptization of secondary particles of agglomerated titanium dioxide due to mechanical loading by kneading under wet conditions with a kneader or the like in the kneading stage during extrusion molding. Therefore, the reduction of the pore volume between the particles is small and the reduction of the gas diffusion efficiency in the pores is small, and the nitrogen oxide removal performance is high. Furthermore, since titanium dioxide and / or titanium composite oxide having a low peak intensity has not been crystallized, the crystallite diameter is small and the specific surface area is large. 2 O 5 Since active metals such as these are highly dispersed, high nitrogen oxide removal performance and the like are brought about.
[0017]
In the present invention, as a result of pursuing what is suitable titanium dioxide powder as a raw material for producing a honeycomb-shaped exhaust gas treatment catalyst, crystals (h, k, l) measured by a powder X-ray diffraction method are investigated. Peak intensity (peak height) X and standard of crystal of raw material titanium dioxide powder on the plane, that is, (101) plane (even in the case of titanium composite oxide, the titanium dioxide existing there is the object of measurement) It has been found that it is important that the ratio with the peak intensity (peak height) Y indicated by the crystal of the sample is in a certain range. That is,
[Equation 3]
0.59 ≦ X / Y ≦ 1.20 (1)
It is one feature of the present invention that the above is satisfied.
[0018]
The standard of anatase-type titanium dioxide crystallinity in the powder X-ray diffraction method according to the present invention is pure anatase-type titanium dioxide (manufactured by Kanto Chemical Co., Inc. However, this product is one standard) 0.300g and pure nickel oxide (Wako Pure Chemicals: grade 1 reagent, naturally pure nickel oxide is not limited to this product, this product is one It is represented by the peak intensity (hereinafter referred to as peak height) Y (mm) of the (101) plane of the anatase-type titanium dioxide crystal of a reference sample obtained by grinding and mixing 1.700 g in an agate mortar.
The reference sample was a Cu X-ray diffractometer (RAD-2C, manufactured by Rigaku Corporation), Cu tube, filter Ni, voltage 30 KV, current 15 mA, scanning speed 1.000 ° / min, full scale. The peak height of the (101) plane of the anatase-type titanium dioxide crystal measured under the measurement condition of 1000 cps is as shown in FIG. In the measured data with this apparatus, the peak on the (101) plane corresponds to the peak of 2θ = 25.280 [°], and the height measured with a ruler of the peak height was 151 mm. In actual measurement data obtained by measuring only pure anatase type titanium dioxide (manufactured by Kanto Chemical Co., Ltd .: reagent grade 1), the height measured with a ruler at a peak height corresponding to a peak of 2θ = 25.280 [°] is 421 mm. there were. Therefore, the reference material in the present invention corresponds to a peak intensity of 35.87% [(151 ÷ 421) × 100] with respect to the peak intensity of the (101) plane of pure anatase type titanium dioxide crystal. The numerical value of the peak height is a numerical value that changes as the measurement conditions and the measuring device change. However, since the equation (1) is an expression relating to the ratio of the peak heights of the object and the reference object, there is no problem. .
[0019]
In the method for defining the peak height ratio in the present invention, by providing the reference sample, the peak height of the (101) plane of the raw material anatase-type titanium dioxide crystal without being affected by the powder X-ray diffractometer or the measurement conditions (Mm) can be used to control the titanium dioxide powder as the catalyst raw material.
[0020]
When the peak height ratio of the titanium dioxide powder on the (101) face of the anatase-type titanium dioxide crystal in the titanium dioxide containing the above-described titanium dioxide and / or titanium dioxide containing an inorganic oxide other than titanium to the reference sample is less than 0.59, Extrusion of the honeycomb structure is extremely difficult, and the mechanical strength of the honeycomb catalyst is significantly reduced. On the other hand, when the peak height ratio is greater than 1.20, catalytic activity such as denitration performance is lowered.
[0021]
In the present invention, when the above-mentioned titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst is only titanium dioxide (not a titanium composite oxide), the above-described peak height ratio is in the range represented by the following formula (2). Is desirable.
[Expression 4]
0.80 ≦ X / Y ≦ 1.20 (2)
[0022]
Moreover, when the above-mentioned titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst is titanium dioxide containing an inorganic oxide other than titanium (titanium composite oxide), the above-mentioned peak height ratio is preferably the following formula (3) It is desirable to be in the range represented by In the case of complex oxides, titania is diluted by the presence of metal oxides other than titania, and the peak height is lowered by itself. In addition, silicon and tungsten are dissolved in the titania crystal structure, so titania alone. Compared to, thermal growth tends to suppress crystal growth. Therefore, the above-described peak height ratio of the titanium composite oxide powder having good moldability and performance is lower than that of the case of titanium dioxide alone (not titanium composite oxide).
[Equation 5]
0.59 ≦ X / Y ≦ 1.06 (3)
[0023]
The peak height X (mm) of the (101) plane of the anatase-type titanium dioxide crystal measured by the aforementioned powder X-ray diffraction method of titanium dioxide and / or titanium composite oxide shows that in the titanium dioxide and / or titanium composite oxide. Sulfate radicals (SO) as impurities 4 ) Or alkali (Na 2 The amount of O) or the type and amount of substances constituting the composite oxide, the firing temperature, the firing atmosphere, the firing time, etc. interact and affect each other. The titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst comprising titanium dioxide and / or titanium dioxide containing an inorganic oxide other than titanium according to the present invention, considering the factors affecting the peak height X (mm), It can be obtained by firing so that the aforementioned peak height ratio satisfies the formula (1).
[0024]
Moreover, the titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst of the present invention has another feature that the crystallite diameter of the anatase crystal (101) plane is in the range of 8 to 22 nm. The crystallite diameter is a value obtained from the Scherrer equation. Generally, there is a correlation between the crystallite size of pure titanium dioxide and the peak height of the X-ray diffraction pattern. However, in the case of titanium dioxide containing impurities such as sulfate radicals and inorganic oxides other than titanium, X-ray diffraction Even if the peak heights in the figure are the same, the size of the crystallite size is different, and also depends on the type and amount of the inorganic oxide contained. Therefore, it is not sufficient to define the titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst of the present invention only by the above peak height ratio. When the crystallite diameter is smaller than 8 nm, a dehydration phenomenon occurs when a kneaded product of titanium dioxide powder is extruded into a honeycomb structure, resulting in poor extrudability and a honeycomb structure with a thin partition wall thickness. I can't get it. On the other hand, when the crystallite size is larger than 22 nm, the catalytic activity such as denitration performance is lowered, which is not preferable.
[0025]
In the present invention, when the above-mentioned titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst is composed of only titanium dioxide (not a titanium composite oxide), the crystallite diameter is preferably in the range of 15 to 22 nm. When the titanium dioxide powder is titanium dioxide (titanium composite oxide) containing an inorganic oxide other than titanium, the crystallite diameter is preferably in the range of 10 to 19 nm.
[0026]
Further, the titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst of the present invention has sulfate radical (SO 4 ) SO in titanium powder on a dry basis 4 As 0.3 to 5.0% by weight. Sulfate radical (SO 4 When the content of) is less than 0.3% by weight, the shrinkage rate during drying and firing of the extruded honeycomb catalyst is increased, so that the obtained catalyst is cracked and the strength is weakened. Further, since the pore volume of the catalyst, particularly the pore volume having a pore diameter of 500 mm or less is small, the nitrogen oxide removal performance is lowered, which is not preferable. In addition, sulfate radical (SO 4 ) Content of more than 5.0% by weight, a phenomenon of dehydration and solidification occurs when a kneaded product of titanium dioxide powder is extruded into a honeycomb structure, resulting in poor fluidity and a molding aid. Since the viscosity of the organic plasticizer and the like used as a lowering, the extrusion molding becomes extremely difficult. The sulfate radical (SO 4 ) Is preferably in the range of 0.4 to 3.5% by weight.
[0027]
In addition, the titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst of the present invention preferably has a particle diameter of 99.9% by weight or more and 45 μm or less. When the particle diameter of the titanium dioxide powder is 45 μm or less is less than 99.9% by weight, that is, when the amount of titanium dioxide powder having a particle diameter of more than 45 μm is more than 0.1% by weight, the partition walls are formed during extrusion. A missing honeycomb structure may be obtained.
[0028]
The honeycomb-shaped exhaust gas treatment catalyst of the present invention preferably contains 60% by weight or more of the above-mentioned titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst. If the above-mentioned titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst is less than 60% by weight, desired denitration activity and organic halogen compound decomposition activity may not be obtained. The honeycomb-shaped exhaust gas treatment catalyst of the present invention preferably contains the above-mentioned titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst in the range of 70 to 99.9% by weight. The honeycomb-shaped exhaust gas treatment catalyst of the present invention contains less than 40% by weight of titanium oxide powder outside the scope of the present invention as long as it contains 60% by weight or more of the above-mentioned titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst. It may be.
[0029]
Moreover, the honeycomb-shaped exhaust gas treatment catalyst of the present invention contains an active component used for a usual catalyst for removing nitrogen oxides. Examples of the active component include metal components such as V, W, Mo, Cr, Mn, Fe, Ni, Cu, Ag, Au, Pd, Y, Ce, Nd, In, and Ir. In particular, vanadium (V) oxide is preferably used because it is inexpensive and has a high nitrogen oxide removal rate. In addition, the content of the active ingredient is the amount of the active ingredient used in a usual catalyst for removing nitrogen oxides, and is usually in the range of 0.1 to 30% by weight in the catalyst as an oxide.
[0030]
The above-mentioned honeycomb-shaped exhaust gas treatment catalyst comprises (a) the above-mentioned titanium dioxide and / or titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst comprising titanium dioxide containing an inorganic oxide other than titanium and an active component or a precursor thereof. A method of extruding into a desired honeycomb shape, drying and firing after kneading with a forming aid or the like to form a kneaded product, (b) the above-mentioned titanium dioxide and / or a dioxide containing an inorganic oxide other than titanium Titanium dioxide powder for honeycomb exhaust gas treatment catalyst made of titanium is kneaded with a molding aid or the like to obtain a kneaded product, then extruded into a desired honeycomb shape, dried and fired, containing an active ingredient It is manufactured by a method of impregnating with an aqueous solution, drying and baking. Note that normal manufacturing conditions can be adopted as conditions for manufacturing the honeycomb-shaped exhaust gas treatment catalyst. FIG. 2 shows an example of a cross-sectional view when the honeycomb structure of the present invention is cut in a direction perpendicular to the extrusion direction in extrusion molding.
[0031]
The honeycomb-shaped exhaust gas treatment catalyst of the present invention has a honeycomb structure in which (i) the honeycomb outer diameter is preferably 30 to 300 mm, more preferably 50 to 200 mm, and (ii) the honeycomb length is 100 to 3000 mm. Preferably, 300 to 1500 mm, (iii) honeycomb through-holes (hereinafter sometimes referred to as openings) are preferably 1 to 15 mm, more preferably 2 to 10 mm, and (iv) honeycomb partition wall thickness is preferably 0.1. It is desirable that the opening ratio of the honeycomb is preferably 60 to 85%, more preferably 70 to 85%. When the shape of the honeycomb structure is out of the range of the shape, it becomes difficult to form, the strength of the honeycomb structure becomes weak, the denitration activity per unit volume, the decomposition activity of the organic halogen compound, etc. become low. and so on.
[0032]
The honeycomb-shaped exhaust gas treatment catalyst of the present invention is a catalytic reduction by adding a reducing agent such as ammonia to exhaust gas containing NOx, particularly NOx and SOx, as well as heavy metal and dust, such as boiler exhaust gas. It is preferably used for the NOx removal method. The catalyst is used under normal denitration treatment conditions. Specifically, the reaction temperature is 150 to 600 ° C., and the space velocity is 1000 to 100,000 hours. ―1 This range is exemplified.
[0033]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by a following example, unless the summary is exceeded.
[0034]
Example 1 <Preparation of Titanium Dioxide Powder for Honeycomb Exhaust Gas Treatment Catalyst (a)>
The titanium sulfate solution obtained from the manufacturing process of titanium dioxide by the sulfuric acid method was hydrolyzed to obtain a metatitanic acid slurry. 25.0 kg of this metatitanic acid slurry was taken out as titanium dioxide, charged into a stirring tank equipped with a reflux condenser, and 30.5 kg of 15 wt% aqueous ammonia was added thereto to adjust the pH to 9.5, and then at 95 ° C. for 1 hour. The mixture was aged by heating with sufficient stirring. Thereafter, the slurry is cooled and taken out, filtered, dehydrated, washed, and SO. 4 4.1 wt% (Dry Basis), Na 2 A washed cake having O of 0.03 wt% (Dry Basis) was obtained. The washed cake was dried at 110 ° C. for 20 hours and then calcined at 509 ° C. for 5 hours to obtain titanium dioxide powder. The titanium dioxide powder was further pulverized to prepare titanium dioxide powder (a) for honeycomb-shaped exhaust gas treatment catalyst comprising titanium dioxide. The titanium dioxide powder (a) for honeycomb-shaped exhaust gas treatment catalyst made of titanium dioxide, using a powder X-ray diffractometer (manufactured by Rigaku Corporation: RAD-2C), Cu tube, filter Ni, voltage 30 KV, current The peak height X of the (101) plane of the anatase-type titanium dioxide crystal measured at 15 mA, the scanning speed of 1.000 ° / min, and the full scale of 1000 cps was 140 mm, and the (101) of the anatase-type titanium dioxide crystal of the reference sample was The peak height Y of the surface was 151 mm. Therefore, the peak intensity ratio of the titanium dioxide powder (a) to the reference sample is
[Formula 6]
X / Y = 140/151 = 0.93
Thus, the condition of formula (1) is satisfied.
The titanium dioxide powder (a) has a crystallite diameter of 17.3 nm determined from the Scherrer equation of the anatase crystal (101) plane, and a sulfate group (SO 4 ) Was 3.5 wt%, and the titanium dioxide powder (a) had a particle size of 99.98 wt% of 45 μm or less.
[0035]
Example 2 <Preparation of titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst (b)>
The washed cake prepared in the same manner as in Example 1 was dried at 110 ° C. for 20 hours, and then fired at 459 ° C. for 5 hours to obtain titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst made of titanium dioxide. The titanium dioxide powder was pulverized to prepare a titanium dioxide powder (b) for honeycomb-shaped exhaust gas treatment catalyst comprising titanium dioxide. The peak height X of the (101) plane of the anatase-type titanium dioxide crystal measured by the powder X-ray diffraction method of the titanium dioxide powder (b) for honeycomb-shaped exhaust gas treatment catalyst made of titanium dioxide is 121 mm, and the peak intensity with respect to the reference sample The ratio (X / Y) was 0.80.
The titanium dioxide powder (b) has a crystallite diameter of 15.2 nm determined from the Scherrer formula of the anatase crystal (101) plane, and a sulfate group (SO 4 ) Was 3.7 wt%, and the titanium dioxide powder (b) had a particle size of 99.98 wt% of 45 μm or less.
[0036]
Example 3 <Preparation of titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst (c)>
The washed cake prepared in the same manner as in Example 1 was dried at 110 ° C. for 20 hours and then calcined at 601 ° C. for 5 hours to obtain titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst made of titanium dioxide. The titanium dioxide powder was pulverized to prepare a titanium dioxide powder (c) for honeycomb-shaped exhaust gas treatment catalyst comprising titanium dioxide. The peak height X of the (101) plane of the anatase-type titanium dioxide crystal measured by the powder X-ray diffraction method of the titanium dioxide powder (c) for honeycomb-shaped exhaust gas treatment catalyst made of titanium dioxide is 177 mm, and the peak intensity with respect to the reference sample The ratio (X / Y) was 1.17.
Further, the titanium dioxide powder (c) has a crystallite diameter of 21.2 nm determined from the Scherrer formula of the anatase crystal (101) plane, and a sulfate group (SO 4 ) Was 2.1 wt%, and the titanium dioxide powder (c) had a particle diameter of 99.98 wt% of 45 μm or less.
[0037]
Comparative Example 1 <Preparation of Titanium Dioxide Powder for Honeycomb Exhaust Gas Treatment Catalyst (d)>
The washed cake prepared in the same manner as in Example 1 was dried at 110 ° C. for 20 hours and then fired at 308 ° C. for 5 hours to obtain titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst made of titanium dioxide. The titanium dioxide powder was pulverized to prepare a titanium dioxide powder (d) for honeycomb-shaped exhaust gas treatment catalyst comprising titanium dioxide. The peak height X of the (101) plane of the anatase-type titanium dioxide crystal measured by the powder X-ray diffraction method of the titanium dioxide powder (d) for honeycomb exhaust gas treatment catalyst made of titanium dioxide is 60 mm, and the peak intensity with respect to the reference sample The ratio (X / Y) was 0.40.
The titanium dioxide powder (d) has a crystallite diameter of 10.2 nm determined from the Scherrer equation of the anatase crystal (101) plane, and a sulfate group (SO 4 ) Was 3.9 wt%, and the titanium dioxide powder (d) had a particle size of 99.98 wt% of 45 μm or less.
[0038]
Comparative Example 2 <Preparation of Titanium Dioxide Powder for Honeycomb Exhaust Gas Treatment Catalyst (e)>
The washed cake prepared in the same manner as in Example 1 was dried at 110 ° C. for 20 hours and then calcined at 685 ° C. for 5 hours to prepare titanium dioxide powder (e) for honeycomb exhaust gas treatment catalyst comprising titanium dioxide. . The titanium dioxide powder was further pulverized to prepare titanium dioxide powder (e) for honeycomb-shaped exhaust gas treatment catalyst comprising titanium dioxide. The peak height X of the (101) plane of the anatase-type titanium dioxide crystal measured by the powder X-ray diffraction method of the titanium dioxide powder (e) for honeycomb-shaped exhaust gas treatment catalyst made of titanium dioxide is 210 mm, and the peak intensity with respect to the reference sample The ratio (X / Y) was 1.39.
Further, the titanium dioxide powder (e) has a crystallite diameter of 24.5 nm determined from the Scherrer equation of the anatase crystal (101) plane, and a sulfate group (SO 4 ) Content was 0.4 wt%, and the titanium dioxide powder (e) had a particle size of 99.98 wt% of 45 μm or less.
[0039]
Comparative Example 3 <Preparation of Titanium Dioxide Powder for Honeycomb Exhaust Gas Treatment Catalyst (f)>
The titanium sulfate solution obtained from the manufacturing process of titanium dioxide by the sulfuric acid method was hydrolyzed to obtain a metatitanic acid slurry. Take 25.0 kg of this metatitanic acid slurry as titanium dioxide and dry it at 110 ° C. for 20 hours to obtain SO 4 Is 8.0 wt% (Dry Basis), Na 2 A dried product having an O content of 0.03 wt% (Dry Basis) was obtained. The dried product was fired at 509 ° C. for 5 hours to obtain titanium dioxide powder. The titanium dioxide powder was pulverized to prepare a titanium dioxide powder (f) for honeycomb-shaped exhaust gas treatment catalyst comprising titanium dioxide. The peak height X of the (101) plane of the anatase-type titanium dioxide crystal measured by the powder X-ray diffraction method of the titanium dioxide powder (f) for honeycomb exhaust gas treatment catalyst made of titanium dioxide is 115 mm, and the peak intensity with respect to the reference sample The ratio (X / Y) was 0.76.
The titanium dioxide powder (f) has a crystallite diameter of 14.7 nm determined from the Scherrer equation of the anatase crystal (101) plane, and a sulfate group (SO 4 ) Content of 5.5 wt%, and the particle diameter of the titanium dioxide powder (f) was 99.98% by weight of 45 μm or less.
[0040]
Example 4 <Preparation of titanium dioxide for honeycomb-shaped exhaust gas treatment catalyst (g)>
The titanium sulfate solution obtained from the manufacturing process of titanium dioxide by the sulfuric acid method was hydrolyzed to obtain a metatitanic acid slurry. 22.5 kg of this metatitanic acid slurry was taken out as titanium dioxide, charged into a stirring tank equipped with a reflux condenser, and 2.82 kg of ammonium paratungstate was added thereto and mixed, and then 30.5 kg of 15 wt% aqueous ammonia was added to adjust the pH to 9 And then aged by heating with sufficient stirring at 95 ° C. for 1 hour. Thereafter, the slurry is cooled and taken out, filtered, dehydrated, washed, and SO. 4 Is 3.0 wt% (Dry Basis), Na 2 A washed cake having O of 0.03 wt% (Dry Basis) was obtained. The washed cake was dried at 110 ° C. for 20 hours, and then calcined at 550 ° C. for 5 hours to obtain a composite oxide (TiO 2) of titanium dioxide and tungsten oxide. 2 -WO 3 The titanium dioxide powder (g) for honeycomb-shaped exhaust gas treatment catalyst was prepared. TiO 2 -WO 3 The composite oxide powder was further pulverized to prepare a honeycomb-shaped exhaust gas treatment titanium dioxide powder (g). TiO 2 -WO 3 TiO 2 powder of titanium dioxide powder (g) for honeycomb-shaped exhaust gas treatment catalyst 2 / WO 3 The weight ratio is 90/10, the peak height X of the (101) plane of the anatase-type titanium dioxide crystal measured by powder X-ray diffraction method is 140 mm, and the peak intensity ratio (X / Y) with respect to the reference sample is 0.93. there were.
The titanium dioxide powder (g) has a crystallite diameter of 16.3 nm determined from the Scherrer equation of the anatase crystal (101) plane, and a sulfate group (SO 4 ) Was 1.7 wt%, and the titanium dioxide powder (g) had a particle size of 99.98 wt% of 45 μm or less.
[0041]
Comparative Example 4 <Preparation of titanium dioxide for honeycomb-shaped exhaust gas treatment catalyst (h)>
The titanium sulfate solution obtained from the manufacturing process of titanium dioxide by the sulfuric acid method was hydrolyzed to obtain a metatitanic acid slurry. Take 22.5 kg of this titanium titanate slurry as titanium dioxide, put it in a stirring tank equipped with a refluxer, add 2.82 kg of ammonium paratungstate, mix, and then add 61.0 kg of 15 wt% aqueous ammonia to adjust the pH to 9 And then aged by heating with sufficient stirring at 95 ° C. for 1 hour. Then, after cooling and taking out the slurry, the steps of filtration, dehydration, and washing with 15% by weight ammonia water were repeated three times to obtain SO. 4 Is 0.3 wt% (Dry Basis), Na 2 A washed cake having O of 0.01 wt% (DryBasis) was obtained. The washed cake was dried at 110 ° C. for 20 hours, then calcined at 550 ° C. for 5 hours, and further pulverized to obtain a composite oxide of titanium dioxide and tungsten oxide (TiO 2). 2 -WO 3 The titanium dioxide powder (h) for honeycomb-shaped exhaust gas treatment catalyst was prepared. TiO 2 -WO 3 TiO 2 of titanium dioxide powder (h) for honeycomb-shaped exhaust gas treatment catalyst comprising 2 / WO 3 The weight ratio is 90/10, the peak height X of the (101) plane of the anatase-type titanium dioxide crystal measured by powder X-ray diffraction method is 152 mm, and the peak intensity ratio (X / Y) with respect to the reference sample is 1.01. there were.
The titanium dioxide powder (h) has a crystallite diameter of 17.7 nm determined from the Scherrer equation of the anatase crystal (101) plane, and a sulfate group (SO 4 ) Content was 0.2 wt%, and the titanium dioxide powder (h) had a particle size of 99.98 wt% of 45 μm or less.
[0042]
Example 5 <Preparation of Titanium Dioxide Powder for Honeycomb Exhaust Gas Treatment Catalyst (i)>
The titanium sulfate solution obtained from the manufacturing process of titanium dioxide by the sulfuric acid method was hydrolyzed to obtain a metatitanic acid slurry. 21.25 kg of this metatitanic acid slurry as titanium dioxide is taken out and charged into a stirring tank equipped with a reflux condenser. 2 After adding and mixing 6.25 kg, the concentration was adjusted to pH 9.5 by adding 30.5 kg of 15 wt% aqueous ammonia, The mixture was aged by heating with sufficient stirring at 95 ° C. for 1 hour. Next, 2.82 kg of ammonium paratungstate was added, and further heat aging was performed at 95 ° C. for 1 hour. Thereafter, the slurry is cooled and taken out, filtered, dehydrated, washed, and SO. 4 Is 3.5 wt% (Dry Basis), Na 2 A washed cake having O of 0.03 wt% (Dry Basis) was obtained. The washed cake was dried at 110 ° C. for 20 hours, calcined at 578 ° C. for 5 hours, and further pulverized to obtain a composite oxide (TiO 2) of titanium dioxide, silica, and tungsten oxide. 2 -SiO 2 -WO 3 The titanium dioxide powder (i) for honeycomb-shaped exhaust gas treatment catalyst was prepared. TiO 2 -SiO 2 -WO 3 TiO 2 of titanium dioxide powder (i) for honeycomb-shaped exhaust gas treatment catalyst comprising 2 / SiO 2 / WO 3 The weight ratio is 85/5/10, the peak height X of the (101) plane of the anatase-type titanium dioxide crystal measured by powder X-ray diffraction method is 95 mm, and the peak intensity ratio (X / Y) with respect to the reference sample is 0 .63.
The titanium dioxide powder (i) has a crystallite diameter of 13.1 nm determined from the Scherrer equation of the anatase crystal (101) plane, and a sulfate group (SO 4 ) Was 1.8 wt%, and the titanium dioxide powder (i) had a particle diameter of 99.98 wt% of 45 μm or less.
[0043]
Comparative Example 5 <Preparation of titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst (j)>
The washed cake prepared in the same manner as in Example 5 was dried at 110 ° C. for 20 hours, then calcined at 503 ° C. for 5 hours, further pulverized, and a composite oxide (TiO 2) of titanium dioxide, silica and tungsten oxide. 2 -SiO 2 -WO 3 The titanium dioxide powder (j) for honeycomb-shaped exhaust gas treatment catalyst was prepared. TiO 2 -SiO 2 -WO 3 TiO 2 of titanium dioxide powder (j) for honeycomb-shaped exhaust gas treatment catalyst comprising 2 / SiO 2 / WO 3 The weight ratio is 85/5/10, the peak height X of the (101) plane of the anatase-type titanium dioxide crystal measured by powder X-ray diffraction method is 65 mm, and the peak intensity ratio (X / Y) with respect to the reference sample is 0 .43.
The titanium dioxide powder (j) has a crystallite diameter of 9.8 nm determined from the Scherrer equation of the anatase type crystal (101) plane, and has a sulfate group (SO 4 ) Content was 3.1 wt%, and the particle diameter of the titanium dioxide powder (j) was 99.98% by weight of 45 μm or less.
[0044]
Example 6 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (a-1)>
To 21.25 kg of the titanium dioxide powder (a) for honeycomb-shaped exhaust gas treatment catalyst of Example 1 was added to a solution obtained by dissolving 1.61 kg of ammonium metavanadate in 0.81 kg of monoethanolamine, and then mixed with ammonia water and water. The pH of the slurry was set to 9, and 1.25 kg of glass fiber (GF), 1.25 kg of acid clay (clay) and 0.5 kg of polyethylene oxide were added, and the mixture was heated and kneaded and kneaded in a kneader. A Japanese product was prepared. Next, the kneaded product was vacuum-extruded with a honeycomb outer diameter of 80 mm □ (meaning a square shape), an opening (through-hole diameter) of 2.55 mm (a square-shaped through-hole diameter of 2.55 mm on one side), It was extruded into a honeycomb shape having a partition wall thickness of 0.45 mm, an aperture ratio of 68.7%, and a length of 300 mm. The molded product was dried at 60 ° C. for 24 hours and then fired at 500 ° C. for 3 hours, and TiO 2 by weight ratio 2 Powder (a) / V 2 O 5 A honeycomb-shaped exhaust gas treatment catalyst (a-1) having a composition of / GF / clay of 85/5/5/5 was prepared. The properties of the catalyst (a-1) are shown in Table 1.
[0045]
Example 7 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (b-1)>
In Example 6, except that the titanium dioxide powder (b) for honeycomb-shaped exhaust gas treatment catalyst of Example 2 was used, TiO2 by weight ratio was exactly the same as Example 6. 2 Powder (b) / V 2 O 5 A honeycomb-shaped exhaust gas treatment catalyst (b-1) having a composition of / GF / clay of 85/5/5/5 was prepared. The properties of the catalyst (b-1) are shown in Table 1.
[0046]
Example 8 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (c-1)>
In Example 6, except that the titanium dioxide powder (c) for honeycomb-shaped exhaust gas treatment catalyst of Example 3 was used, TiO2 by weight ratio was exactly the same as Example 6. 2 Powder (c) / V 2 O 5 A honeycomb-shaped exhaust gas treatment catalyst (c-1) having a composition of / GF / clay of 85/5/5/5 was prepared. Table 1 shows the properties of the catalyst (c-1).
[0047]
Comparative Example 6 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (d-1)>
In Example 6, except that the titanium dioxide powder (d) for honeycomb-shaped exhaust gas treatment catalyst of Comparative Example 1 was used, kneading and kneading were performed in a kneader in the same manner as in Example 6, and kneading suitable for extrusion molding A product was prepared. Next, the kneaded product was extruded and formed into a honeycomb shape having a honeycomb outer diameter of 80 mm □, an opening of 2.55 mm, a partition wall thickness of 0.45 mm, an aperture ratio of 68.7%, and a length of 300 mm using a vacuum extruder. The Japanese product caused a dehydration phenomenon in the vacuum extrusion molding machine and could not be extruded into a honeycomb shape, and a sample of the honeycomb-shaped exhaust gas treatment catalyst (d-1) could not be collected. The composition of the catalyst (d-1) is TiO 2 Powder (d) / V 2 O 5 / GF / clay is in a 85/5/5/5 weight ratio. Table 1 shows the properties of the catalyst (d-1).
[0048]
Comparative Example 7 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (e-1)>
In Example 6, except that the honeycomb-shaped exhaust gas treatment catalyst titanium dioxide powder (e) of Comparative Example 2 was used, the weight ratio of TiO was exactly the same as in Example 6. 2 Powder (e) / V 2 O 5 A honeycomb-shaped exhaust gas treatment catalyst (e-1) having a composition of / GF / clay of 85/5/5/5 was prepared. The properties of the catalyst (e-1) are shown in Table 1.
[0049]
Comparative Example 8 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (f-1)>
In Example 6, except for using the titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst of Comparative Example 3 (f), kneading and kneading was carried out in a kneader in the same manner as in Example 6, and kneading suitable for extrusion molding. A product was prepared. Next, the kneaded product was extruded with a vacuum extruder into a honeycomb shape having a honeycomb outer diameter of 80 mm □, an opening of 2.55 mm, a partition wall thickness of 0.45 mm, an aperture ratio of 68.7%, and a length of 300 mm. The Japanese product caused a dehydration phenomenon in a vacuum extrusion molding machine and could not be extruded into a honeycomb shape, and a sample of the honeycomb-shaped exhaust gas treatment catalyst (f-1) could not be collected. The composition of the catalyst (f-1) is TiO 2 Powder (f) / V 2 O 5 / GF / clay is in a 85/5/5/5 weight ratio. The properties of the catalyst (f-1) are shown in Table 1.
[0050]
Example 9 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (g-1)>
In Example 6, except that the titanium dioxide powder (g) for honeycomb-shaped exhaust gas treatment catalyst of Example 4 was used, TiO2 by weight ratio was exactly the same as Example 6. 2 -WO 3 Powder (g) / V 2 O 5 A honeycomb-shaped exhaust gas treatment catalyst (g-1) having a composition of / GF / clay of 85/5/5/5 was prepared. The properties of the catalyst (g-1) are shown in Table 1.
[0051]
Comparative Example 9 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (h-1)>
In Example 6, except that the honeycomb-shaped exhaust gas treatment catalyst titanium dioxide powder (h) of Comparative Example 4 was used, TiO2 by weight ratio was exactly the same as Example 6. 2 -WO 3 Powder (h) / V 2 O 5 A honeycomb-shaped exhaust gas treatment catalyst (h-1) having a composition of / GF / clay of 85/5/5/5 was prepared. The properties of the catalyst (h-1) are shown in Table 1.
[0052]
Example 10 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (gi-1)>
1.61 kg of ammonium metavanadate was added to a mixture of 16.25 kg of the titanium dioxide powder (g) for honeycomb-shaped exhaust gas treatment catalyst of Example 4 and 5.0 kg of titanium dioxide powder (i) for honeycomb-shaped exhaust gas treatment catalyst of Example 5. A solution obtained by dissolving in 0.81 kg of monoethanolamine was added, then ammonia water and water were added to adjust the pH of this mixed slurry to 9, and glass fiber 1.25 kg, acid clay 1.25 kg and polyethylene oxide 0.5 kg And kneaded and kneaded to prepare a kneaded product suitable for extrusion molding. Next, the kneaded product was extruded into a honeycomb shape having a honeycomb outer diameter of 80 mm □, an opening of 2.55 mm, a partition wall thickness of 0.45 mm, an aperture ratio of 68.7%, and a length of 300 mm using a vacuum extrusion molding machine. Was dried at 60 ° C. for 24 hours and then calcined at 500 ° C. for 3 hours. 2 -WO 3 Powder (g) / TiO 2 -SiO 2 -WO 3 Powder (i) / V 2 O 5 A honeycomb-shaped exhaust gas treatment catalyst (gi-1) having a composition of / GF / clay of 65/20/5/5/5 was prepared. The properties of the catalyst (gi-1) are shown in Table 1.
[0053]
Example 11 <Preparation of Honeycomb Exhaust Gas Treatment Catalyst (gj-1)>
In Example 10, except that 5.0 kg of the titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst (j) of Comparative Example 5 was used instead of the titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst of Example 5 (i). Just as in Example 10, TiO in weight ratio. 2 -WO 3 Powder (g) / TiO 2 -SiO 2 -WO 3 Powder (j) / V 2 O 5 A honeycomb-shaped exhaust gas treatment catalyst (gj-1) having a composition of / GF / clay of 65/20/5/5/5 was prepared. This catalyst contained the titanium dioxide powder (j) of Comparative Example 5, but had good moldability because it contained 60% by weight or more of the titanium dioxide powder (g) of Example 4. The properties of the catalyst (gj-1) are shown in Table 1.
[0054]
Comparative Example 10 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (jg-1)>
In Example 10, a mixture of 16.25 kg of the honeycomb-shaped exhaust gas treatment catalyst titanium dioxide powder (j) of Comparative Example 5 and 5.0 kg of the honeycomb-shaped exhaust gas treatment catalyst titanium dioxide powder (g) of Example 4 was used. In the same manner as in Example 10, a kneader was heated and kneaded and kneaded to prepare a kneaded product suitable for extrusion molding. Next, the kneaded product was extruded and formed into a honeycomb shape having a honeycomb outer diameter of 80 mm □, an opening of 2.55 mm, a partition wall thickness of 0.45 mm, an aperture ratio of 68.7%, and a length of 300 mm using a vacuum extruder. The Japanese product caused a dehydration phenomenon in a vacuum extrusion molding machine, and it was difficult to extrude into a honeycomb shape, and a sample of the honeycomb-shaped exhaust gas treatment catalyst (jg-1) could not be collected. The composition of the catalyst (jg-1) is TiO 2 by weight ratio. 2 -WO 3 Powder (g) / TiO 2 -SiO 2 -WO 3 Powder (j) / V 2 O 5 / GF / clay is 20/65/5/5/5. Properties of the catalyst (jg-1) are shown in Table 1.
[0055]
Example 12 <Nitrogen oxide removal performance test>
Catalysts of Examples 6 to 11 (a-1), (b-1), (c-1), (g-1), (gi-1), (gj-1) and Comparative Examples 6 to 10 A nitrogen oxide removal performance test was performed using (d-1), (e-1), (f-1), (h-1), and (jg-1).
Each of the honeycomb catalysts was 250 mm long and the number of through-holes was cut into 8 × 8 pieces (one representing one through-hole) and filled in a flow reactor, and the denitration rate was measured under the following conditions. . The NOx removal rate was determined by the following equation by measuring the nitrogen oxide (NOx) concentration in the gas before and after contact with the catalyst with a chemirmi-type nitrogen oxide analyzer.
[Expression 7]
[0056]
[Table 1]
As is apparent from Table 1, the catalysts (a-1), (b-1) and (c-1) of Examples 6 to 8 and the catalysts (d-1) of Comparative Examples 6 to 8 having the same composition, When (e-1) and (f-1) are compared, the peak intensity ratio with respect to the reference sample of the (101) plane of the anatase-type titanium dioxide crystal measured by the powder X-ray diffraction method of the commonly used titanium dioxide powder raw material is The catalysts (a-1), (b-1), and (c-1) of the low examples have high denitration performance, and the peak intensity ratio of the titanium dioxide powder to the reference sample of Comparative Example 7 (e) -1) The catalyst is markedly degraded in performance. Further, regarding the catalyst (d-1) of the comparative example in which the peak intensity ratio of the titanium dioxide powder to the reference sample was less than 0.59, it was extremely difficult to form a honeycomb sample. Furthermore, the peak intensity ratio of the titanium dioxide powder with respect to the reference sample satisfies the condition of the formula (1), but sulfate radical (SO 4 The catalyst (f-1) of Comparative Example 8 containing a large amount of) has a poor moldability and a honeycomb sample could not be collected. Note that the honeycomb-shaped exhaust gas treatment catalyst in which the partition wall of the honeycomb structure is thin is intended for exhaust gas that does not contain dust, and in this case, the wear rate does not matter.
[0058]
The catalysts (gi-1) and (gj-1) are the same in that they contain 65% by weight of the raw material (g) as the main raw material, but the peak intensity ratio of the titanium dioxide powder as the auxiliary raw material to the reference sample is Different. In this case, it can be seen that the catalyst (gj-1) using the raw material (j) having a lower peak intensity ratio with respect to the reference sample of titanium dioxide powder has higher denitration performance. Here, since the titanium dioxide powder (j) has a peak intensity ratio of 0.43 with respect to the reference sample, there is a concern that the moldability deteriorates, but the titanium dioxide powder with a peak intensity ratio of 0.93 with respect to the reference sample. Since 60g% or more of (g) was contained, there was no problem in moldability. However, the catalyst (jg-1) in which the titanium dioxide powder (j) is 65% and the titanium dioxide powder (g) is 20% by weight has poor moldability and it was impossible to collect a honeycomb sample. .
[0059]
Example 13 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (a-2)>
In Examples 13 and 14 and Comparative Example 11, the wear rate of the partition walls is measured by mixing sand that wears the partition walls of the honeycomb structure into the reaction gas. Therefore, the initial thickness of the partition is also thicker than those of Examples 1-12.
A solution obtained by dissolving 0.32 kg of ammonium metavanadate in 0.16 kg of monoethanolamine was added to 23.50 kg of the titanium dioxide powder (a) for honeycomb-shaped exhaust gas treatment catalyst of Example 1, and then ammonia water and water were added. In addition, the mixed slurry was adjusted to pH 9, and 1.25 kg of glass fiber (GF) and 0.5 kg of polyethylene oxide were further added, and the mixture was heated and kneaded and kneaded to prepare a kneaded product suitable for extrusion molding. Next, the kneaded product was extruded into a honeycomb shape having a honeycomb outer diameter of 82 mm □, a mesh opening of 6.70 mm, a partition wall thickness of 1.20 mm, an aperture ratio of 66.8%, and a length of 300 mm using a vacuum extrusion molding machine. Was dried at 60 ° C. for 24 hours and then calcined at 600 ° C. for 3 hours to obtain TiO 2. 2 / V 2 O 5 A honeycomb-shaped exhaust gas treatment catalyst (a-2) having a composition of / GF of 94/1/5% by weight was prepared. Table 2 shows the properties of the catalyst (a-2).
[0060]
Comparative Example 11 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (d-2)>
In Example 13, TiO 2 was exactly the same as Example 13 except that the titanium dioxide powder (d) for honeycomb-shaped exhaust gas treatment catalyst of Comparative Example 1 was used. 2 / V 2 O 5 A honeycomb-shaped exhaust gas treatment catalyst (d-2) having a composition and shape with / GF of 94/1/5% by weight was prepared. The honeycomb-shaped catalyst had a honeycomb outer diameter of 82 mm □, an opening of 6.70 mm, a partition wall thickness of 1.20 mm, a large honeycomb opening, and the partition wall was thick. Table 2 shows the properties of the catalyst (d-2).
[0061]
Example 14 <Preparation of honeycomb-shaped exhaust gas treatment catalyst (ai-2)>
In Example 13, a mixture of 17.25 kg of the titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst (a) of Example 1 and 6.25 kg of the titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst of Example 5 (i) was used. Is exactly the same as in Example 13 except that TiO 2 / TiO 2 -WO 3 -SiO 2 / V 2 O 5 A catalyst (ai-2) having a composition of / GF = 69/25/1/5% by weight was prepared. Properties of the catalyst (ai-2) are shown in Table 2.
[0062]
Example 15
Using the catalysts (a-2) and (ai-2) of Examples 13 and 14, and the catalyst (d-2) of Comparative Example 11, a nitrogen oxide removal performance test and a catalyst abrasion test were performed.
<Nitrogen oxide removal performance test>
A test sample cut out from each honeycomb catalyst at a length of 300 mm and 3 × 3 was filled into a flow reactor, and the denitration rate was measured under the following conditions. The NOx removal rate was determined by the following equation by measuring the nitrogen oxide (NOx) concentration in the gas before and after contact with the catalyst with a chemirmi-type nitrogen oxide analyzer.
[Equation 8]
A test sample cut from each honeycomb catalyst with a length of 100 mm and 9 × 9 was filled in a flow reactor, and a gas containing sand was flowed under the following conditions, and the wear rate was measured from the reduced weight of the catalyst. The amount of sand passed is determined by collecting the weight with a cyclone and measuring the weight after measurement.
[Table 2]
From Table 2, the catalyst (d-2) using the titanium dioxide powder (d) having a peak intensity ratio of 0.40 with respect to the reference sample of the titanium dioxide powder as the main raw material has high denitration performance but extremely high wear rate. . The catalyst (d-2) of Comparative Example 11 is unsuitable as an exhaust gas treatment catalyst containing dust such as coal-fired boiler exhaust gas, because the catalyst wears and decreases due to dust in the exhaust gas during use. On the other hand, the catalyst (a-2) using the titanium dioxide powder (a) having a peak intensity ratio of 0.93 relative to the reference sample of the raw material titanium dioxide powder has an extremely low wear rate and high wear strength. Further, the catalyst (ai-2) in which a part of the titanium dioxide powder raw material is replaced with the raw material (i) has a further improved performance than (a-2) while having an appropriate wear strength. I understand.
[0065]
【The invention's effect】
The titanium dioxide powder for honeycomb exhaust gas treatment catalyst comprising titanium dioxide and / or titanium composite oxide of the present invention has a peak intensity ratio X / Y of (101) plane of anatase type titanium dioxide crystal measured by powder X-ray diffraction method. Is in the range of 0.59 to 1.20 in the formula (1) and the crystallite diameter is in the range of 8 to 22 nm, and the sulfate radical (SO 4 ) Since the content is in the range of 0.3 to 5.0% by weight, the honeycomb catalyst can be easily extruded. The honeycomb-shaped exhaust gas treatment catalyst using 60% by weight or more of the raw material of the present invention has high nitrogen oxide removal performance, and a porous thin-walled honeycomb-shaped catalyst can be easily produced. Therefore, the required amount of catalyst can be reduced, and the exhaust gas treatment catalyst device can be made compact. Furthermore, since the honeycomb-shaped exhaust gas treatment catalyst has high wear resistance, the life of the catalyst is extended.
[Brief description of the drawings]
FIG. 1 is a reduced drawing of an X-ray diffraction diagram drawn based on a measuring apparatus and measuring conditions described in the text, and the actual peak height is 151 mm.
Fig. 2 is a cross-sectional view of a honeycomb structure according to an example of the present invention cut at right angles to the extrusion direction.
Claims (6)
（ａ）粉末Ｘ線回折法で測定したアナターゼ型二酸化チタン結晶の（１０１）面の二酸化チタン粉末の基準試料に対するピーク強度比が下記式（１）
【数１】
０．５９≦Ｘ／Ｙ≦１．２０ （１）
〔ここで、Ｙは、純粋なアナターゼ型二酸化チタン（関東化学製：試薬鹿１級）０．３００ｇと純粋な酸化ニッケル（和光純薬製：試薬１級）１．７００ｇをメノウ乳鉢で粉砕混合した基準試料のアナターゼ型二酸化チタン結晶の（１０１）面のピーク強度（ｍｍ）であり、Ｘは、ハニカム状排ガス処理触媒用二酸化チタン粉末のアナターゼ型二酸化チタン結晶の（１０１）面のピーク強度（ｍｍ）である〕
で表される範囲にある、
（ｂ）アナターゼ型結晶（１０１）面の結晶子径が８〜２２ｎｍの範囲にある、
（ｃ）硫酸根（ＳＯ４）を０．３〜５．０重量％の範囲で含有する、
の性状を有することを特徴とするハニカム状排ガス処理触媒用二酸化チタン粉末。Titanium dioxide powder for honeycomb-shaped exhaust gas treatment catalyst comprising titanium dioxide and / or titanium composite oxide, wherein (a) titanium dioxide powder of (101) face of anatase type titanium dioxide crystal measured by powder X-ray diffraction method The peak intensity ratio with respect to the reference sample is the following formula (1)
[Expression 1]
0.59 ≦ X / Y ≦ 1.20 (1)
[Where Y is 0.300 g of pure anatase type titanium dioxide (Kanto Chemical Co., Ltd .: reagent deer grade 1) and 1.700 g of pure nickel oxide (Wako Pure Chemicals Co., Ltd .: reagent grade 1) are ground and mixed in an agate mortar. Is the peak intensity (mm) of the (101) plane of the anatase-type titanium dioxide crystal of the reference sample, and X is the peak intensity of the (101) plane of the anatase-type titanium dioxide crystal of the titanium dioxide powder for honeycomb exhaust gas treatment catalyst ( mm)]
In the range represented by
(B) The crystallite diameter of the anatase crystal (101) plane is in the range of 8 to 22 nm.
(C) containing sulfate radical (SO 4 ) in the range of 0.3 to 5.0% by weight,
A titanium dioxide powder for a honeycomb-shaped exhaust gas treatment catalyst characterized by having the following properties:
（ｉ）ハニカムの外径が３０〜３００ｍｍ、
（ii）ハニカムの長さが１００〜３０００ｍｍ、
（iii）ハニカムの貫通孔が１〜１５ｍｍ、
（iv）ハニカムの隔壁厚が０．１〜２ｍｍ、
（ｖ）ハニカムの開口率が６０〜８５％The honeycomb-shaped exhaust gas treatment catalyst according to claim 4, wherein the honeycomb-shaped exhaust gas treatment catalyst is a honeycomb structure having the following shapes (i) to (v).
(I) the outer diameter of the honeycomb is 30 to 300 mm,
(Ii) The honeycomb has a length of 100 to 3000 mm,
(Iii) 1 to 15 mm of through-holes in the honeycomb,
(Iv) The partition wall thickness of the honeycomb is 0.1 to 2 mm,
(V) The aperture ratio of the honeycomb is 60 to 85%
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| US7491676B2 (en) * | 2004-10-19 | 2009-02-17 | Millennium Inorganic Chemicals | High activity titania supported metal oxide DeNOx catalysts |
| JPWO2006132097A1 (en) | 2005-06-09 | 2009-01-08 | 株式会社日本触媒 | Titanium oxide, exhaust gas treatment catalyst, and exhaust gas purification method |
| KR100710204B1 (en) | 2005-09-08 | 2007-04-20 | 동부일렉트로닉스 주식회사 | CMOS image sensor and method for manufacturing the same |
| DE102006020158B4 (en) * | 2006-05-02 | 2009-04-09 | Argillon Gmbh | Extruded full catalyst and process for its preparation |
| JP5266766B2 (en) * | 2008-01-16 | 2013-08-21 | トヨタ自動車株式会社 | Resin film structure |
| US7879759B2 (en) * | 2009-02-16 | 2011-02-01 | Augustine Steve M | Mobile DeNOx catalyst |
| JP2012139625A (en) * | 2010-12-28 | 2012-07-26 | Jgc Catalysts & Chemicals Ltd | Titanium containing powder, exhaust gas treatment catalyst, and method of manufacturing titanium containing powder |
| JP6132498B2 (en) * | 2012-09-21 | 2017-05-24 | 株式会社日本触媒 | Titanium / silicon / tungsten oxide, denitration catalyst using the same, method for preparing the oxide, and denitration method |
| 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 |
| CN104797333A (en) * | 2012-11-08 | 2015-07-22 | 揖斐电株式会社 | Honeycomb structure |
| JP2014180645A (en) * | 2013-03-21 | 2014-09-29 | Nippon Shokubai Co Ltd | Denitration catalyst and denitration method |
| JP5947939B2 (en) * | 2015-03-10 | 2016-07-06 | 日揮触媒化成株式会社 | Titanium-containing powder, exhaust gas treatment catalyst, and method for producing titanium-containing powder |
| CN110694640B (en) * | 2019-10-22 | 2023-01-17 | 邢台旭阳科技有限公司 | Water-resistant sulfur-resistant denitration catalyst and preparation method thereof |
| CN113735164A (en) * | 2021-08-18 | 2021-12-03 | 安徽迪诺环保新材料科技有限公司 | Nano titanium dioxide for high-sulfur and high-plasticity denitration and preparation method thereof |
| CN114433069A (en) * | 2022-01-26 | 2022-05-06 | 浙江科卓环保科技有限公司 | Production process of high-ash flue gas honeycomb denitration catalyst |
| CN115739081B (en) * | 2022-12-28 | 2024-02-09 | 大唐(江苏)环保装备公司 | Denitration catalyst and preparation method thereof |
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