JP2005021780A - Method for producing exhaust gas treatment catalyst - Google Patents
Method for producing exhaust gas treatment catalyst Download PDFInfo
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- JP2005021780A JP2005021780A JP2003189044A JP2003189044A JP2005021780A JP 2005021780 A JP2005021780 A JP 2005021780A JP 2003189044 A JP2003189044 A JP 2003189044A JP 2003189044 A JP2003189044 A JP 2003189044A JP 2005021780 A JP2005021780 A JP 2005021780A
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- catalyst
- exhaust gas
- gas treatment
- weight
- titanium dioxide
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- 239000003054 catalyst Substances 0.000 title claims abstract description 114
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 20
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 99
- 239000004408 titanium dioxide Substances 0.000 claims abstract description 40
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 39
- 150000003682 vanadium compounds Chemical class 0.000 claims abstract description 14
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims abstract description 11
- 238000010304 firing Methods 0.000 claims abstract description 4
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical group O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims description 60
- 239000007789 gas Substances 0.000 claims description 42
- 238000000354 decomposition reaction Methods 0.000 claims description 13
- 150000002894 organic compounds Chemical class 0.000 claims description 10
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 9
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 7
- 229910052721 tungsten Inorganic materials 0.000 claims description 7
- 239000010937 tungsten Substances 0.000 claims description 7
- 229910052710 silicon Inorganic materials 0.000 claims description 5
- 239000010703 silicon Substances 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 3
- 238000000465 moulding Methods 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 2
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 abstract description 66
- 238000000926 separation method Methods 0.000 abstract description 14
- 230000003197 catalytic effect Effects 0.000 abstract description 10
- 239000003365 glass fiber Substances 0.000 description 24
- 239000002253 acid Substances 0.000 description 22
- 239000000203 mixture Substances 0.000 description 19
- 239000002994 raw material Substances 0.000 description 19
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 18
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 18
- 239000004927 clay Substances 0.000 description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 15
- 230000000694 effects Effects 0.000 description 12
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 11
- 235000011114 ammonium hydroxide Nutrition 0.000 description 11
- 238000002360 preparation method Methods 0.000 description 11
- 239000000243 solution Substances 0.000 description 11
- 229910010413 TiO 2 Inorganic materials 0.000 description 10
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 description 9
- 238000001125 extrusion Methods 0.000 description 9
- 238000000034 method Methods 0.000 description 9
- 239000000377 silicon dioxide Substances 0.000 description 9
- 239000002002 slurry Substances 0.000 description 9
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 description 8
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 8
- 239000011268 mixed slurry Substances 0.000 description 8
- 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 8
- 238000005192 partition Methods 0.000 description 8
- 229910001930 tungsten oxide Inorganic materials 0.000 description 8
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 4
- 229910052809 inorganic oxide Inorganic materials 0.000 description 4
- 238000004898 kneading Methods 0.000 description 4
- 235000012239 silicon dioxide Nutrition 0.000 description 4
- 229910052720 vanadium Inorganic materials 0.000 description 4
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- 239000004480 active ingredient Substances 0.000 description 3
- 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 3
- 239000011734 sodium Substances 0.000 description 3
- 229910000348 titanium sulfate Inorganic materials 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 229910001593 boehmite Inorganic materials 0.000 description 2
- PASHVRUKOFIRIK-UHFFFAOYSA-L calcium sulfate dihydrate Chemical compound O.O.[Ca+2].[O-]S([O-])(=O)=O PASHVRUKOFIRIK-UHFFFAOYSA-L 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 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 2
- 230000007423 decrease Effects 0.000 description 2
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 2
- 239000002440 industrial waste Substances 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- ZNOKGRXACCSDPY-UHFFFAOYSA-N tungsten trioxide Chemical compound O=[W](=O)=O ZNOKGRXACCSDPY-UHFFFAOYSA-N 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- KVGZZAHHUNAVKZ-UHFFFAOYSA-N 1,4-Dioxin Chemical compound O1C=COC=C1 KVGZZAHHUNAVKZ-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 229910052684 Cerium Inorganic materials 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
- MXRIRQGCELJRSN-UHFFFAOYSA-N O.O.O.[Al] Chemical compound O.O.O.[Al] MXRIRQGCELJRSN-UHFFFAOYSA-N 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
- 238000003915 air pollution Methods 0.000 description 1
- 229910021529 ammonia Inorganic materials 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
- 229910001680 bayerite Inorganic materials 0.000 description 1
- 239000011218 binary composite Substances 0.000 description 1
- 206010006451 bronchitis Diseases 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 235000012438 extruded product Nutrition 0.000 description 1
- -1 for example Chemical compound 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 239000011491 glass wool Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 210000004400 mucous membrane Anatomy 0.000 description 1
- 201000009240 nasopharyngitis Diseases 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 150000002896 organic halogen compounds Chemical class 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- OGUCKKLSDGRKSH-UHFFFAOYSA-N oxalic acid oxovanadium Chemical compound [V].[O].C(C(=O)O)(=O)O OGUCKKLSDGRKSH-UHFFFAOYSA-N 0.000 description 1
- WIWVNQBYNTWQOW-UHFFFAOYSA-L oxovanadium(2+);diacetate Chemical compound [V+2]=O.CC([O-])=O.CC([O-])=O WIWVNQBYNTWQOW-UHFFFAOYSA-L 0.000 description 1
- BQFYGYJPBUKISI-UHFFFAOYSA-N potassium;oxido(dioxo)vanadium Chemical compound [K+].[O-][V](=O)=O BQFYGYJPBUKISI-UHFFFAOYSA-N 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 206010039083 rhinitis Diseases 0.000 description 1
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- CMZUMMUJMWNLFH-UHFFFAOYSA-N sodium metavanadate Chemical compound [Na+].[O-][V](=O)=O CMZUMMUJMWNLFH-UHFFFAOYSA-N 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000004936 stimulating effect Effects 0.000 description 1
- 208000024891 symptom Diseases 0.000 description 1
- 239000011206 ternary composite Substances 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- UUUGYDOQQLOJQA-UHFFFAOYSA-L vanadyl sulfate Chemical compound [V+2]=O.[O-]S([O-])(=O)=O UUUGYDOQQLOJQA-UHFFFAOYSA-L 0.000 description 1
- 229940041260 vanadyl sulfate Drugs 0.000 description 1
- 229910000352 vanadyl sulfate Inorganic materials 0.000 description 1
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- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
【課題】人体に有害な五酸化バナジウムを含有する排ガス処理触媒の高い触媒活性を低下させることなく、活性成分である五酸化バナジウムの分離、飛散を抑制して触媒を製造する方法の提供。
【解決手段】（１）バナジウム化合物、（２）二酸化チタンおよび（３）Ａｌ２Ｏ３として０．５〜１５重量％（触媒基準）範囲のアルミナ水和物、とを混合し、成形、乾燥、焼成することを特徴とする排ガス処理触媒の製造方法。
【選択図】 なしAn object of the present invention is to provide a method for producing a catalyst by suppressing the separation and scattering of vanadium pentoxide, which is an active component, without reducing the high catalytic activity of an exhaust gas treatment catalyst containing vanadium pentoxide which is harmful to the human body.
SOLUTION: (1) Vanadium compound, (2) Titanium dioxide, and (3) Alumina hydrate in the range of 0.5 to 15% by weight (catalyst basis) as Al 2 O 3 are mixed, molded and dried. And a method for producing an exhaust gas treatment catalyst, characterized by firing.
[Selection figure] None
Description
【０００１】
【発明の属する技術分野】
本発明は、排ガス中に含まれる窒素酸化物や塩素化有機化合物などを分解除去する排ガス処理触媒の製造方法に関し、さらに詳しくは、使用中もしくは使用して活性劣化した五酸化バナジウムを含有する使用済み触媒を加熱再生処理する際などに、人体に有害（粘膜を刺激する作用があり、鼻カタル、気管支炎などの症状がでる）な五酸化バナジウムの飛散が抑制されると共に、高い触媒活性を有する排ガス処理触媒を製造する方法に関する。
【０００２】
【従来の技術】
従来、ガス焚きタービンなどの火力発電所、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、さらに自動車などから排出される燃焼排ガス中の窒素酸化物や有機ハロゲン化合物を分解する排ガス処理触媒には、五酸化バナジウムを含有する触媒は高い触媒活性を示すことから五酸化バナジウムが活性成分として使用されている。
【０００３】
例えば、特許文献１の実施例１ＮＯ．２１には、酸化チタン１重量部に対し０．０８重量部のアルミナを含有するＡｌ２Ｏ３・ＴｉＯ２担体にＶ２Ｏ５を８ｗｔ％担持した「窒素酸化物と一酸化炭素の同時処理用触媒」が開示されている。
【０００４】
また、特許文献２には、本質的に１０〜５０重量％のアルミナと５０〜９０重量％のチタニアとからなる混合担体に、１〜１０重量％のバナジウム、０．１〜５重量％のニッケル、０．１〜５重量％のモリブデン及び１〜１５重量％のタングステンを含むダイオキシン除去用触媒が開示されている。
前述の担体の製造ではアルミナ源としてγ−アルミナなどの酸化アルミナが使用されている。
【０００５】
【特許文献１】
特開昭６２−２５０９４７号公報
【特許文献２】
特開２００２−２４８３５２号公報
【０００６】
前述の排ガス処理触媒の活性成分として使用される人体に有害な五酸化バナジウムは、融点が６８０℃であり、１５０〜６００℃までの温度範囲においては、通常昇華はあり得ない。しかしながら、反応排ガス中に水蒸気を多量に含む場合には６８０℃以下の温度であっても一部の五酸化バナジウムが触媒から分離、飛散して系外に放出されることがある。飛散量は反応温度が高い程多いが、２５０℃などの低温領域においても反応時間が長期間に亘れば時間とともに増える傾向にある。
また、人体に有害な五酸化バナジウムを含有する使用済み排ガス処理触媒を乾式で熱処理を行って再生処理する場合に、触媒中の一部の五酸化バナジウムが触媒から分離、飛散して系外に放出される問題があった。
【０００７】
【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、人体に有害な五酸化バナジウムを含有する排ガス処理触媒の高い触媒活性を低下させることなく、活性成分である五酸化バナジウムの分離、飛散を抑制して触媒を製造する方法を提供する点にある。
【０００８】
【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、バナジウムはアルミナと親和性が強いこと、しかしアルミナの形で用いるとバナジウム化合物の脱硝活性を低下させることおよびアルミナ水和物の形で用いればバナジウム化合物の脱硝活性を低下させることが少ないことを見出し、本発明を完成するに至った。
【０００９】
本発明の第１は、（１）バナジウム化合物、（２）二酸化チタンおよび（３）Ａｌ２Ｏ３として０．５〜１５重量％（触媒基準）範囲のアルミナ水和物、とを混合し、成形、乾燥、焼成することを特徴とする排ガス処理触媒の製造方法に関する。
本発明の第２は、前記排ガス処理触媒が、さらに（４）タングステンをＷＯ３として３．５〜９．０重量％（触媒基準）範囲で含有するものである請求項１の排ガス処理触媒の製造方法に関する。
本発明の第３は、前記排ガス処理触媒が、さらに（５）珪素をＳｉＯ２として０．１〜３．０重量％（触媒基準）範囲で含有するものである請求項１または２記載の排ガス処理触媒の製造方法に関する。
本発明の第４は、前記排ガス処理触媒が、窒素酸化物分解除去触媒である請求項１〜３いずれか記載の排ガス処理触媒の製造方法に関する。
本発明の第５は、前記排ガス処理触媒が、塩素化有機化合物分解除去触媒である請求項１〜３いずれか記載の排ガス処理触媒の製造方法に関する。
【００１０】
【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。
【００１１】
本発明でのバナジウム化合物としては、例えば五酸化バナジウム、メタバナジン酸アンモン、メタバナジン酸ナトリウム、バナジン酸カリウム、硫酸バナジル、蓚酸バナジル、酢酸バナジルなどの化合物が例示される。これらの化合物は、水に溶解した水溶液の状態で使用することが好ましい。なお、バナジウム化合物の量は、通常の排ガス処理触媒の五酸化バナジウム（Ｖ２Ｏ５）含有量の範囲が採用され、具体的には、触媒基準で０．５〜２０重量％の範囲が好適である。
【００１２】
また、本発明では、二酸化チタンおよびアルミナ水和物が原料として使用される。二酸化チタンとしては、通常、脱硝触媒の製造原料に使用される二酸化チタンを使用する。特に、アナターゼ型の結晶構造を有する二酸化チタンは好適である。また、本発明での二酸化チタンは他の無機酸化物を含有することができる。
二酸化チタン以外に、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）などのチタン以外の元素よりなる無機酸化物が挙げられる。特に、二酸化チタンと酸化タングステン（ＴｉＯ２−ＷＯ３）、二酸化チタンとシリカ（ＴｉＯ２−ＳｉＯ２）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）の三元系複合酸化物は、ＴｉＯ２にＳｉＯ２、ＷＯ３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。二酸化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所望の活性を有する排ガス処理触媒が得られないことがある。
【００１３】
前述の二酸化チタンと酸化タングステン（ＴｉＯ２−ＷＯ３）の二元系複合酸化物では、タングステンの含有量が、触媒基準でＷＯ３として３．５〜９．０重量％範囲となるようにすることが好ましい。排ガス処理触媒が窒素酸化物分解除去触媒または塩素化有機化合物分解除去触媒である場合には、酸化タングステン（ＷＯ３）含有量が触媒基準で３．５重量％より少ないと排ガス処理性能が低下することがあり、また酸化タングステン（ＷＯ３）含有量が９．０重量％より多いと活性成分である五酸化バナジウムの分離、飛散を抑制する効果が低下することがある。前述の二酸化チタンと酸化タングステン（ＴｉＯ２−ＷＯ３）の二元系複合酸化物でのタングステンの含有量は、更に好ましくは、触媒基準でＷＯ３として４．５〜９．０重量％範囲となるようにすることが望ましい。
【００１４】
また、前述の二酸化チタンとシリカ（ＴｉＯ２−ＳｉＯ２）の二元系複合酸化物では、珪素の含有量が、触媒基準でＳｉＯ２として０．１〜３．０重量％範囲となるようにすることが好ましい。排ガス処理触媒中の二酸化珪素含有量が３．０重量％より多くなると、混合物を成形する場合に成形性が悪くなることがあり、また、二酸化珪素含有量が０．１重量％より少ない場合には活性成分である五酸化バナジウムの分離、飛散の抑制効果が低下することがある。
【００１５】
更に、前述の二酸化チタンと酸化タングステンおよびシリカ（ＴｉＯ２−ＷＯ３−ＳｉＯ２）の三元系複合酸化物では、タングステンの含有量が触媒基準でＷＯ３として３．５〜９．０重量％範囲となるように、また、珪素の含有量が触媒基準でＳｉＯ２として０．１〜３．０重量％範囲となるようにすることが好ましい。
【００１６】
本発明でのアルミナ水和物は、焼成により活性アルミナに相転移するアルミナ水和物である。具体的には、ジプサイト、バイアライト、ノルストランダイト、ベーマイト、ベーマイトゲル、無定形アルミナゲルなどが挙げられる。特にジプサイトは好適である。
本発明では、前記アルミナ水和物を触媒基準でＡｌ２Ｏ３として０．５〜１５重量％範囲となるように、前記バナジウム化合物および前記二酸化チタンと混合し、成形する。アルミナ水和物の量が、触媒基準でＡｌ２Ｏ３として０．５重量％より少ない場合には、五酸化バナジウムが触媒から分離、飛散するのを抑制する効果が得られない。また、アルミナ水和物の量が、触媒基準でＡｌ２Ｏ３として１５重量％より多い場合には、窒素酸化物分解除去能や塩素化有機化合物分解除去能などの触媒活性が低下する。アルミナ水和物の量は、好ましくは、触媒基準でＡｌ２Ｏ３として１〜１０重量％範囲にあることが望ましい。
【００１７】
前述の（１）バナジウム化合物、前述の（２）二酸化チタンおよび前述の（３）アルミナ水和物、とを混合し、成形する方法としては、通常の窒素酸化物分解除去触媒や塩素化有機化合物分解除去触媒などの排ガス処理触媒の製造における混合、成形方法が採用可能である。例えば、二酸化チタン粉末とアルミナ水和物とをニーダに所定の量を入れ、更に、所定量のバナジウム化合物の水溶液を加えて混合し、必要に応じて粘土などを加えて混練、捏和して押出成形に適した捏和物を調製し、所望の形状に押出成形する方法が挙げられる。
押出成形された成形物は、通常の方法で乾燥、焼成される。例えば、該成形物を５０〜２００℃で１〜５０時間乾燥し、次いで４００〜８００℃で０．５〜１０時間焼成して排ガス処理触媒を得る。
【００１８】
本発明の方法で得られる排ガス処理触媒は、バナジウム化合物とアルミナ水和物とを混合して乾燥、焼成するとき、アルミナ水和物が結晶水を失って活性アルミナに相転移する際に五酸化バナジウムとの相互作用により適度に結合することで、本来の窒素酸化物分解除去能や塩素化有機化合物分解除去能などの触媒活性を失うことなく、触媒から五酸化バナジウムが分離、飛散しにくくなるものと思われる。しかし、アルミナ水和物の代わりに活性アルミナを使用した場合は、五酸化バナジウムの分離、飛散を抑制する効果はあるが、排ガス処理性能が低下するので好ましくない。さらに触媒中に二酸化珪素および酸化タングステンを所定量含有させることで、本来の窒素酸化物分解除去能や塩素化有機化合物分解除去能などの触媒活性を失うことなく、触媒からの五酸化バナジウムの分離、飛散を抑制する効果がさらに増すものと思われる。
【００１９】
本発明の方法で得られる排ガス処理触媒は、触媒基準で二酸化チタン（ＴｉＯ２）含有量が好ましくは６０重量％以上、更に好ましくは６５重量％以上となるように調製することが望ましい。二酸化チタン含有量が６０重量％未満では窒素酸化物分解除去能や塩素化有機化合物分解除去能などの触媒活性が低下することがある。
【００２０】
本発明の方法で得られる排ガス処理触媒は、通常の排ガス処理条件で使用可能であり、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都市ゴミ、産業廃棄物などを処理する焼却炉、さらに自動車などから排出される燃焼排ガス中の窒素酸化物分解除去や塩素化有機化合物分解除去、アンモニア分解除去などに適用される。
【００２１】
【実施例】
以下、本発明を実施例により具体的に説明するが、本発明はこれらにより限定されるものではない。
【００２２】
参考例１＜二酸化チタン原料（ａ）の調製＞
硫酸法による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酸化チタンとして２５．０ｋｇに相当する量だけ取り出し、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、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３．０重量％（Ｄｒｙ Ｂａｓｉｓ）、Ｎａ２Ｏが０．０３重量％（Ｄｒｙ Ｂａｓｉｓ）の洗浄ケ−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時間焼成して酸化チタンからなる二酸化チタン原料（ａ）を調製した。
【００２３】
参考例２＜二酸化チタン原料（ｂ）の調製＞
硫酸法による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酸化チタンとして２２．５ｋｇに相当する量だけ取り出し、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、その後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３．０重量％（Ｄｒｙ Ｂａｓｉｓ）、Ｎａ２Ｏが０．０３重量％（Ｄｒｙ Ｂａｓｉｓ）の洗浄ケ−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時間焼成して酸化チタンと酸化タングステンとの複合酸化物（重量比でＴｉＯ２／ＷＯ３＝９０／１０）からなる二酸化チタン原料（ｂ）を調製した。
【００２４】
参考例３＜二酸化チタン原料（ｃ）の調製＞
硫酸法による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酸化チタンとして２１．２５ｋｇに相当する量だけ取り出し、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、その後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−を取り出し、濾過、脱水、洗浄して、ＳＯ４が３．０重量％（Ｄｒｙ Ｂａｓｉｓ）、Ｎａ２Ｏが０．０３重量％（Ｄｒｙ Ｂａｓｉｓ）の洗浄ケ−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（重量比でＴｉＯ２／ＳｉＯ２／ＷＯ３＝８５／５／１０）からなる二酸化チタン原料（ｃ）を調製した。
【００２５】
比較例１＜触媒の調製（ａ―１）＞（アルミナが無いケース）
メタバナジン酸アンモニウム１．２８ｋｇをモノエタノールアミン０．６４ｋｇで溶解した溶液を、参考例１の二酸化チタン原料（ａ）２１．５ｋｇに加え、次いでアンモニア水を加え、この混合スラリーのｐＨを９とし、さらに水を加えて水分３８％とし、ニーダにて２５分加熱混練捏和した。その後グラスファイバー（ＧＦ）１．２５ｋｇ、酸性白土１．２５ｋｇ、ポリエチレンオキサイド０．５ｋｇを添加し、さらに３０分混練捏和して捏和物を調製した。次いで該捏和物を真空押し出し成形機で、外径７９ｍｍ□、目開き４．２８ｍｍ、隔壁厚０．８８ｍｍ、長さ４００ｍｍのハニカム状に押出し成形し、成形物を６０℃で４８時間乾燥後、５３０℃で３時間焼成して、重量比でＴｉＯ２／Ｖ２Ｏ５／ＧＦ／酸性白土が８６／４／５／５の組成をもつ触媒（ａ―１）を調製した。触媒（ａ―１）の性状を表１に示す。
【００２６】
実施例１＜触媒の調製（ａ―２）＞
メタバナジン酸アンモニウム１．２８ｋｇをモノエタノールアミン０．６４ｋｇで溶解した溶液を、参考例１の二酸化チタン原料（ａ）２１．４ｋｇとジプサイト形アルミナ水和物０．１９ｋｇに加え、次いでアンモニア水を加え、この混合スラリーのｐＨを９とし、さらに水を加えて水分３８％とし、ニーダにて２５分加熱混練捏和した。その後グラスファイバー（ＧＦ）１．２５ｋｇ、酸性白土１．２５ｋｇ、ポリエチレンオキサイド０．５ｋｇを添加し、さらに３０分混練捏和して捏和物を調製した。次いで該捏和物を真空押し出し成形機で、外径７９ｍｍ□、目開き４．２８ｍｍ、隔壁厚０．８８ｍｍ、長さ４００ｍｍのハニカム状に押出し成形し、成形物を６０℃で４８時間乾燥後、５３０℃で３時間焼成して、重量比でＴｉＯ２／Ａｌ２Ｏ３／Ｖ２Ｏ５／ＧＦ／酸性白土が８５．５／０．５／４／５／５の組成をもつ触媒（ａ―２）を調製した。触媒（ａ―２）の性状を表１に示す。
【００２７】
実施例２＜触媒の調製（ａ―３）＞
メタバナジン酸アンモニウム１．２８ｋｇをモノエタノールアミン０．６４ｋｇで溶解した溶液を、参考例１の二酸化チタン原料（ａ）２０．２５ｋｇとジプサイト形アルミナ水和物１．９２ｋｇに加え、次いでアンモニア水を加え、この混合スラリーのｐＨを９とし、さらに水を加えて水分３８％とし、ニーダにて２５分加熱混練捏和した。その後グラスファイバー（ＧＦ）１．２５ｋｇ、酸性白土１．２５ｋｇ、ポリエチレンオキサイド０．５ｋｇを添加し、さらに３０分混練捏和して捏和物を調製した。次いで該捏和物を真空押し出し成形機で、外径７９ｍｍ□、目開き４．２８ｍｍ、隔壁厚０．８８ｍｍ、長さ４００ｍｍのハニカム状に押出し成形し、成形物を６０℃で４８時間乾燥後、５３０℃で３時間焼成して、重量比でＴｉＯ２／Ａｌ２Ｏ３／Ｖ２Ｏ５／ＧＦ／酸性白土が８１／５／４／５／５の組成をもつ触媒（ａ―３）を調製した。触媒（ａ―３）の性状を表１に示す。
【００２８】
実施例３＜触媒の調製（ａ―４）＞
メタバナジン酸アンモニウム１．２８ｋｇをモノエタノールアミン０．６４ｋｇで溶解した溶液を、参考例１の二酸化チタン原料（ａ）１９．００ｋｇとジプサイト形アルミナ水和物３．８４ｋｇに加え、次いでアンモニア水を加え、この混合スラリーのｐＨを９とし、さらに水を加えて水分３８％とし、ニーダにて２５分加熱混練捏和した。その後グラスファイバー（ＧＦ）１．２５ｋｇ、酸性白土１．２５ｋｇ、ポリエチレンオキサイド０．５ｋｇを添加し、さらに３０分混練捏和して捏和物を調製した。次いで該捏和物を真空押し出し成形機で、外径７９ｍｍ□、目開き４．２８ｍｍ、隔壁厚０．８８ｍｍ、長さ４００ｍｍのハニカム状に押出し成形し、成形物を６０℃で４８時間乾燥後、５３０℃で３時間焼成して、重量比でＴｉＯ２／Ａｌ２Ｏ３／Ｖ２Ｏ５／ＧＦ／酸性白土が７６／１０／４／５／５の組成をもつ触媒（ａ―４）を調製した。触媒（ａ―４）の性状を表１に示す。
【００２９】
比較例２＜触媒の調製（ａ―５）＞（アルミナ量が多すぎるケース）
メタバナジン酸アンモニウム１．２８ｋｇをモノエタノールアミン０．６４ｋｇで溶解した溶液を、参考例１の二酸化チタン原料（ａ）１６．５０ｋｇと、ジプサイト形アルミナ水和物７．６７ｋｇに加え、次いでアンモニア水を加え、この混合スラリーのｐＨを９とし、さらに水を加えて水分３８％とし、ニーダにて２５分加熱混練捏和した。その後グラスファイバー（ＧＦ）１．２５ｋｇ、酸性白土１．２５ｋｇ、ポリエチレンオキサイド０．５ｋｇを添加し、さらに３０分混練捏和して捏和物を調製した。次いで該捏和物を真空押し出し成形機で、外径７９ｍｍ□、目開き４．２８ｍｍ、隔壁厚０．８８ｍｍ、長さ４００ｍｍのハニカム状に押出し成形し、成形物を６０℃で４８時間乾燥後、５３０℃で３時間焼成して、重量比でＴｉＯ２／Ａｌ２Ｏ３／Ｖ２Ｏ５／ＧＦ／酸性白土が６６／２０／４／５／５の組成をもつ触媒（ａ―５）を調製した。触媒（ａ―５）の性状を表１に示す。
【００３０】
比較例３＜触媒の調製（ａ―６）＞（アルミナ源としてアルミナ水和物を使用しないケース）
メタバナジン酸アンモニウム１．２８ｋｇをモノエタノールアミン０．６４ｋｇで溶解した溶液を参考例１の二酸化チタン原料（ａ）２０．２５ｋｇと活性アルミナ（Ａｌ２Ｏ３）１．２５ｋｇに、加え、次いでアンモニア水を加えこの混合スラリーのｐＨを９とし、さらに水を加えて水分３８％とし、ニーダにて２５分加熱混練捏和した。その後グラスファイバー（ＧＦ）１．２５ｋｇ、酸性白土１．２５ｋｇ、ポリエチレンオキサイド０．５ｋｇを添加し、さらに３０分混練捏和して捏和物を調製した。次いで該捏和物を真空押し出し成形機で、外径７９ｍｍ□、目開き４．２８ｍｍ、隔壁厚０．８８ｍｍ、長さ４００ｍｍのハニカム状に押出し成形し、成形物を６０℃で４８時間乾燥後、５３０℃で３時間焼成して、重量比でＴｉＯ２／Ａｌ２Ｏ３／Ｖ２Ｏ５／ＧＦ／酸性白土が８１／５／４／５／５の組成をもつ触媒（ａ―６）を調製した。触媒（ａ―６）の性状を表１に示す。
【００３１】
実施例４＜触媒の調製（ｂ―１）＞
メタバナジン酸アンモニウム１．２８ｋｇをモノエタノールアミン０．６４ｋｇで溶解した溶液を参考例２の二酸化チタン原料（ｂ）２０．２５ｋｇとジプサイト形アルミナ水和物１．９２ｋｇに加え、次いでアンモニア水を加えこの混合スラリーのｐＨを９とし、さらに水を加えて水分３８％とし、ニーダにて２５分加熱混練捏和した。その後グラスファイバー（ＧＦ）１．２５ｋｇ、酸性白土１．２５ｋｇ、ポリエチレンオキサイド０．５ｋｇを添加しさらに３０分混練捏和して捏和物を調製した。次いで該捏和物を真空押し出し成形機で、外径７９ｍｍ□、目開き４．２８ｍｍ、隔壁厚０．８８ｍｍ、長さ４００ｍｍのハニカム状に押出し成形し、成形物を６０℃で４８時間乾燥後、５３０℃で３時間焼成して、重量比でＴｉＯ２／ＷＯ３／Ａｌ２Ｏ３／Ｖ２Ｏ５／ＧＦ／酸性白土が７２．９／８．１／５／４／５／５の組成をもつ触媒（ｂ―１）を調製した。触媒（ｂ―１）の性状を表１に示す。
【００３２】
実施例５＜触媒の調製（ｂｃ―１）＞
メタバナジン酸アンモニウム１．２８ｋｇをモノエタノールアミン０．６４ｋｇで溶解した溶液を参考例１の二酸化チタン原料（ｂ）１２．７５ｋｇと参考例２の二酸化チタン原料（ｃ）７．５０ｋｇおよびジプサイト形アルミナ水和物１．９２ｋｇに加え、次いでアンモニア水を加えこの混合スラリーのｐＨを９とし、さらに水を加えて水分３８％とし、ニーダにて２５分加熱混練捏和した。その後グラスファイバー（ＧＦ）１．２５ｋｇ、酸性白土１．２５ｋｇ、ポリエチレンオキサイド０．５ｋｇを添加しさらに３０分混練捏和して捏和物を調製した。次いで該捏和物を真空押し出し成形機で、外径７９ｍｍ□、目開き４．２８ｍｍ、隔壁厚０．８８ｍｍ、長さ４００ｍｍのハニカム状に押出し成形し、成形物を６０℃で４８時間乾燥後、５３０℃で３時間焼成して、重量比でＴｉＯ２／ＷＯ３／ＳｉＯ２／Ａｌ２Ｏ３／Ｖ２Ｏ５／ＧＦ／酸性白土が７１．４／８．１／１．５／５／４／５／５の組成をもつ触媒（ｂｃ―１）を調製した。触媒（ｂｃ―１）の性状を表１に示す。
【００３３】
応用例１
実施例１〜５の触媒（ａ−２）、（ａ−３）、（ａ−４）、（ｂ−１）（ｂｃ−１）および比較例１〜３の触媒（ａ−１）、（ａ−５）、（ａ−６）をそれぞれ使用して、窒素酸化物除去能試験および五酸化バナジウム分離、飛散試験を行った。
＜窒素酸化物分解除去能試験＞
各ハニカム触媒から３００ｍｍの長さで５×５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。
脱硝率（％）＝〔｛未接触ガス中のＮＯｘ（ｐｐｍ）−接触後のガス中のＮＯｘ（ｐｐｍ）｝／未接触ガス中のＮＯｘ（ｐｐｍ）〕×１００
【００３４】
＜五酸化バナジウム分離、飛散試験＞
各ハニカム触媒から２５０ｍｍの長さで４×５目に切り出した試験試料を流通式反応器に充填し、下記条件で五酸化バナジウムの分離、飛散量を測定した。五酸化バナジウムの分離、飛散量測定法は、試験終了後、流通式反応器の内壁および流通式反応器出口に充填したガラスウールに付着した五酸化バナジウムを１規定のシュウ酸で洗い流し容量５００ｍＬとした。これをバナジウムとしてＩＣＰにて定量し五酸化バナジウムとして換算して分離、飛散量とした。
【００３５】
【表１】
比較例１の触媒（ａ−１）は五酸化バナジウムの分離、飛散量が極めて多いのに対し、アルミナ水和物をＡｌ２Ｏ３として０．５〜１０重量％含有する実施例の触媒は五酸化バナジウムの分離、飛散量が少なくなるが、窒素酸化物除去（脱硝）性能に関しては、実用に支障が出る程の低下は生じなかった。しかしながら、アルミナ水和物をＡｌ２Ｏ３として２０重量％含有する比較例２の触媒（ａ−５）は五酸化バナジウムの分離、飛散量が殆どなくなるが、脱硝性能に関しては極端に性能低下した。なお、工業的に使用される触媒の脱硝性能は、前記試験条件での脱硝率が７５％以上であることが望ましい。
【００３７】
触媒製造時にアルミナ水和物を使用せず活性アルミナ（Ａｌ２Ｏ３）を５重量％使用した比較例３の触媒（ａ−６）は五酸化バナジウムの分離、飛散を抑制する効果は（ａ−３）と同等であるが、脱硝性能が極端に低下した。
【００３８】
二酸化チタン原料（ｂ）を用いた実施例４の触媒（ｂ−１）は、ＷＯ３を８．１重量％含有しているため、アルミナ水和物をＡｌ２Ｏ３として５重量％含有する実施例２の触媒（ａ−３）に比べ、脱硝性能がさらに高かった。
また、二酸化チタン原料（ｃ）を３０重量％添加した実施例５の触媒（ｂｃ−１）は、触媒中の二酸化珪素含量が１．５重量％と適度であるため、比較例１の触媒（ａ−１）に比べ、五酸化バナジウムの分離、飛散量が約７割程度減少し、また高い脱硝性能を維持しているのが判る。
【００３９】
【発明の効果】
本発明の触媒は、窒素酸化物分解除去能や塩素化有機化合物分解除去能などの高い触媒活性を維持しつつも、触媒中の五酸化バナジウムの分離、飛散を抑制する効果を有するので、人体に有害な五酸化バナジウムによる大気汚染が防止される。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an exhaust gas treatment catalyst that decomposes and removes nitrogen oxides, chlorinated organic compounds, etc. contained in exhaust gas, and more specifically, uses that contain vanadium pentoxide that has been used or has been actively degraded. When the used catalyst is heated and regenerated, the scattering of vanadium pentoxide, which is harmful to the human body (having an effect of stimulating the mucous membrane and causing symptoms such as nasal catarrh and bronchitis), is suppressed, and high catalytic activity is achieved. The present invention relates to a method for producing an exhaust gas treatment catalyst.
[0002]
[Prior art]
Conventionally, combustion furnaces at various plants such as gas-fired turbines, thermal power plants such as steel mills, incinerators for treating municipal waste and industrial waste, and nitrogen oxides in combustion exhaust gas emitted from automobiles, etc. As an exhaust gas treatment catalyst for decomposing an organic halogen compound, vanadium pentoxide is used as an active component because a catalyst containing vanadium pentoxide exhibits high catalytic activity.
[0003]
For example, Example 1 of Patent Document 1 NO. 21 contains Al containing 0.08 part by weight of alumina with respect to 1 part by weight of titanium oxide. 2 O 3 ・ TiO 2 V on carrier 2 O 5 Is disclosed as “a catalyst for simultaneous treatment of nitrogen oxides and carbon monoxide”.
[0004]
Patent Document 2 discloses that a mixed carrier consisting essentially of 10 to 50% by weight of alumina and 50 to 90% by weight of titania is mixed with 1 to 10% by weight of vanadium and 0.1 to 5% by weight of nickel. , A dioxin removal catalyst comprising 0.1 to 5 wt% molybdenum and 1 to 15 wt% tungsten is disclosed.
In the production of the carrier, alumina oxide such as γ-alumina is used as the alumina source.
[0005]
[Patent Document 1]
JP 62-250947 A
[Patent Document 2]
JP 2002-248352 A
[0006]
Vanadium pentoxide which is harmful to the human body used as an active component of the above-described exhaust gas treatment catalyst has a melting point of 680 ° C. and usually cannot sublime in the temperature range of 150 to 600 ° C. However, when the reaction exhaust gas contains a large amount of water vapor, some vanadium pentoxide may be separated from the catalyst and scattered and released out of the system even at a temperature of 680 ° C. or lower. The amount of scattering increases as the reaction temperature increases. However, even in a low temperature region such as 250 ° C., the amount of scattering tends to increase with time if the reaction time is long.
In addition, when used exhaust gas treatment catalyst containing vanadium pentoxide, which is harmful to human body, is subjected to regeneration treatment by dry heat treatment, some vanadium pentoxide in the catalyst is separated from the catalyst and scattered to the outside of the system. There was a problem that was released.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and its purpose is to reduce the high catalytic activity of an exhaust gas treatment catalyst containing vanadium pentoxide that is harmful to the human body, without reducing the high catalytic activity of vanadium pentoxide, which is an active ingredient. The object is to provide a method for producing a catalyst while suppressing separation and scattering.
[0008]
[Means for Solving the Problems]
As a result of various investigations, the present inventors have found that vanadium has a strong affinity for alumina, but when used in the form of alumina, it reduces the denitration activity of vanadium compounds, and when used in the form of alumina hydrate, vanadium compounds The present inventors have found that there is little reduction in the denitration activity of the present invention and have completed the present invention.
[0009]
The first of the present invention is (1) a vanadium compound, (2) titanium dioxide, and (3) Al. 2 O 3 And an alumina hydrate in the range of 0.5 to 15% by weight (catalyst reference), and molding, drying, and firing.
In the second aspect of the present invention, the exhaust gas treatment catalyst further comprises (4) tungsten as WO. 3 The present invention relates to a method for producing an exhaust gas treatment catalyst according to claim 1, which is contained in the range of 3.5 to 9.0% by weight (catalyst reference).
According to a third aspect of the present invention, the exhaust gas treatment catalyst further comprises (5) silicon as SiO. 2 The present invention relates to a method for producing an exhaust gas treatment catalyst according to claim 1 or 2, wherein the content is 0.1 to 3.0% by weight (based on catalyst).
A fourth aspect of the present invention relates to the method for producing an exhaust gas treatment catalyst according to any one of claims 1 to 3, wherein the exhaust gas treatment catalyst is a nitrogen oxide decomposition removal catalyst.
The fifth aspect of the present invention relates to the method for producing an exhaust gas treatment catalyst according to any one of claims 1 to 3, wherein the exhaust gas treatment catalyst is a chlorinated organic compound decomposition removal catalyst.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail.
[0011]
Examples of the vanadium compound in the present invention include compounds such as vanadium pentoxide, ammonium metavanadate, sodium metavanadate, potassium vanadate, vanadyl sulfate, vanadyl oxalate, and vanadyl acetate. These compounds are preferably used in the form of an aqueous solution dissolved in water. The amount of the vanadium compound is determined by the amount of vanadium pentoxide (V 2 O 5 ) The range of the content is employed, and specifically, the range of 0.5 to 20% by weight based on the catalyst is suitable.
[0012]
In the present invention, titanium dioxide and alumina hydrate are used as raw materials. As titanium dioxide, titanium dioxide which is usually used as a raw material for producing a denitration catalyst is used. In particular, titanium dioxide having an anatase type crystal structure is suitable. Moreover, the titanium dioxide in this invention can contain another inorganic oxide.
In addition to titanium dioxide, for example, silicon (Si), zirconium (Zr), tungsten (W), molybdenum (Mo), vanadium (V), manganese (Mn), copper (Cu), tin (Sn), barium (Ba ) And inorganic oxides made of elements other than titanium such as cerium (Ce). In particular, titanium dioxide and tungsten oxide (TiO 2 -WO 3 ), Titanium dioxide and silica (TiO 2 -SiO 2 ) So-called binary complex oxides, as well as titanium dioxide, tungsten oxide and silica (TiO 2 -WO 3 -SiO 2 ) Ternary complex oxide is TiO 2 And SiO 2 , WO 3 Has a highly dispersed structure, the progress of crystallization by heating and baking, and 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 dioxide is preferably smaller than the amount of titanium dioxide. If the content of inorganic oxides other than titanium exceeds the amount of titanium dioxide, an exhaust gas treatment catalyst having desired activity may not be obtained.
[0013]
Titanium dioxide and tungsten oxide (TiO2) 2 -WO 3 )), The tungsten content is WO on a catalyst basis. 3 Is preferably in the range of 3.5 to 9.0% by weight. When the exhaust gas treatment catalyst is a nitrogen oxide decomposition removal catalyst or a chlorinated organic compound decomposition removal catalyst, tungsten oxide (WO 3 ) If the content is less than 3.5% by weight based on the catalyst, the exhaust gas treatment performance may be reduced, and tungsten oxide (WO 3 ) When the content is more than 9.0% by weight, the effect of suppressing the separation and scattering of vanadium pentoxide which is an active ingredient may be lowered. Titanium dioxide and tungsten oxide (TiO2) 2 -WO 3 More preferably, the content of tungsten in the binary composite oxide is WO on a catalyst basis. 3 As a result, it is desirable to be in the range of 4.5 to 9.0 wt%.
[0014]
In addition, the aforementioned titanium dioxide and silica (TiO 2 -SiO 2 ), The silicon content is SiO on a catalyst basis. 2 Is preferably in the range of 0.1 to 3.0% by weight. When the silicon dioxide content in the exhaust gas treatment catalyst is more than 3.0% by weight, the moldability may be deteriorated when the mixture is molded, and when the silicon dioxide content is less than 0.1% by weight. May reduce the effect of suppressing the separation and scattering of the active ingredient vanadium pentoxide.
[0015]
Further, the above-mentioned titanium dioxide, tungsten oxide and silica (TiO 2 -WO 3 -SiO 2 ) Ternary composite oxide, the tungsten content is WO on a catalyst basis. 3 As a range of 3.5 to 9.0 wt%, the silicon content is SiO on a catalyst basis. 2 Is preferably in the range of 0.1 to 3.0% by weight.
[0016]
The alumina hydrate in the present invention is an alumina hydrate that undergoes phase transition to activated alumina upon firing. Specific examples include gypsite, bayerite, norstrandite, boehmite, boehmite gel, and amorphous alumina gel. Gypsite is particularly suitable.
In the present invention, the alumina hydrate is Al on a catalyst basis. 2 O 3 And mixed with the vanadium compound and the titanium dioxide so as to be in the range of 0.5 to 15% by weight. The amount of alumina hydrate is Al on a catalyst basis. 2 O 3 If the amount is less than 0.5% by weight, the effect of preventing vanadium pentoxide from separating and scattering from the catalyst cannot be obtained. Also, the amount of alumina hydrate is Al on a catalyst basis. 2 O 3 When the amount is more than 15% by weight, the catalytic activity such as the ability to decompose and remove nitrogen oxides and the ability to decompose and remove chlorinated organic compounds decreases. The amount of alumina hydrate is preferably Al on a catalyst basis. 2 O 3 Is preferably in the range of 1 to 10% by weight.
[0017]
The above-mentioned (1) vanadium compound, the above-mentioned (2) titanium dioxide, and the above-mentioned (3) alumina hydrate are mixed and molded. Mixing and molding methods in the production of exhaust gas treatment catalysts such as decomposition removal catalysts can be employed. For example, a predetermined amount of titanium dioxide powder and alumina hydrate are put into a kneader, and an aqueous solution of a predetermined amount of vanadium compound is added and mixed, and if necessary, kneaded and kneaded with clay. A method of preparing a kneaded product suitable for extrusion molding and extruding it into a desired shape is mentioned.
The extruded product is dried and fired by a usual method. For example, the molded product is dried at 50 to 200 ° C. for 1 to 50 hours and then calcined at 400 to 800 ° C. for 0.5 to 10 hours to obtain an exhaust gas treatment catalyst.
[0018]
The exhaust gas treatment catalyst obtained by the method of the present invention is a pentoxide when the vanadium compound and alumina hydrate are mixed and dried and calcined, and when the alumina hydrate loses crystal water and undergoes phase transition to activated alumina. By moderately binding with the interaction with vanadium, vanadium pentoxide is difficult to separate and scatter from the catalyst without losing the catalytic activity such as the ability to decompose and remove nitrogen oxides and chlorinated organic compounds. It seems to be. However, the use of activated alumina instead of alumina hydrate is not preferable because it has an effect of suppressing separation and scattering of vanadium pentoxide, but the exhaust gas treatment performance is lowered. Furthermore, by containing a predetermined amount of silicon dioxide and tungsten oxide in the catalyst, separation of vanadium pentoxide from the catalyst without losing the catalytic activity such as the ability to decompose and remove nitrogen oxides and chlorinated organic compounds. It seems that the effect of suppressing scattering is further increased.
[0019]
The exhaust gas treatment catalyst obtained by the method of the present invention is titanium dioxide (TiO 2) on a catalyst basis. 2 ) The content is preferably adjusted to 60% by weight or more, more preferably 65% by weight or more. When the titanium dioxide content is less than 60% by weight, the catalytic activity such as the ability to decompose and remove nitrogen oxides and the ability to decompose and remove chlorinated organic compounds may decrease.
[0020]
The exhaust gas treatment catalyst obtained by the method of the present invention can be used under normal exhaust gas treatment conditions, and is used in combustion furnaces, municipal waste, industrial waste from various factories such as heavy oil, coal-fired boilers, thermal power plants, steelworks, etc. It is applied to incinerators that treat the above, and nitrogen oxide decomposition removal, chlorinated organic compound decomposition removal, ammonia decomposition removal, etc. from combustion exhaust gas discharged from automobiles and the like.
[0021]
【Example】
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
[0022]
Reference Example 1 <Preparation of Titanium Dioxide Raw Material (a)>
The titanium sulfate solution obtained from the manufacturing process of titanium oxide by the sulfuric acid method was hydrolyzed to obtain a metatitanic acid slurry. This metatitanic acid slurry was taken out as titanium oxide in an amount corresponding to 25.0 kg, charged into a stirring tank equipped with a reflux condenser, and 30.5 kg of 15 wt% aqueous ammonia was added to adjust the pH to 9.5. The mixture was aged by heating with sufficient stirring at 1 ° C. for 1 hour. Thereafter, the slurry is cooled and taken out, filtered, dehydrated, washed, and SO. 4 Is 3.0% by weight (Dry Basis), Na 2 A washing cake with O of 0.03% by weight (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 prepare a titanium dioxide raw material (a) comprising titanium oxide.
[0023]
Reference Example 2 <Preparation of Titanium Dioxide Raw Material (b)>
The titanium sulfate solution obtained from the manufacturing process of titanium oxide by the sulfuric acid method was hydrolyzed to obtain a metatitanic acid slurry. This metatitanic acid slurry is taken out as titanium oxide in an amount corresponding to 22.5 kg, charged in a stirring tank equipped with a refluxer, and added with 2.82 kg of ammonium paratungstate, and then mixed with 30.5 kg of 15 wt% aqueous ammonia. In addition, the pH was adjusted to 9.5, followed by heat aging at 95 ° C. for 1 hour with sufficient stirring. Thereafter, the slurry is cooled and taken out, filtered, dehydrated, washed, and SO. 4 Is 3.0% by weight (Dry Basis), Na 2 A washing cake with O of 0.03% by weight (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 of titanium oxide and tungsten oxide (TiO 2 by weight ratio). 2 / WO 3 = 90/10) A titanium dioxide raw material (b) was prepared.
[0024]
Reference Example 3 <Preparation of Titanium Dioxide Raw Material (c)>
The titanium sulfate solution obtained from the manufacturing process of titanium oxide by the sulfuric acid method was hydrolyzed to obtain a metatitanic acid slurry. This metatitanic acid slurry is taken out as titanium oxide in an amount corresponding to 21.25 kg, charged into a stirring tank equipped with a reflux, and silica sol [SiO 2 2 After adding and mixing 6.25 kg, the pH was adjusted to 9.5 by adding 30.5 kg of 15 wt% aqueous ammonia, and then the pH was adjusted to 9.5. 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 3.0% by weight (Dry Basis), Na 2 A washing cake with O of 0.03% by weight (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 of titanium oxide, silica and tungsten oxide (TiO 2 by weight ratio). 2 / SiO 2 / WO 3 = 85/5/10) A titanium dioxide raw material (c) was prepared.
[0025]
Comparative Example 1 <Catalyst Preparation (a-1)> (Case without Alumina)
A solution in which 1.28 kg of ammonium metavanadate was dissolved in 0.64 kg of monoethanolamine was added to 21.5 kg of the titanium dioxide raw material (a) in Reference Example 1, then ammonia water was added to adjust the pH of the mixed slurry to 9, Further, water was added to a moisture content of 38%, and the mixture was kneaded and kneaded with a kneader for 25 minutes. Thereafter, 1.25 kg of glass fiber (GF), 1.25 kg of acid clay, and 0.5 kg of polyethylene oxide were added, and the mixture was further kneaded and kneaded for 30 minutes to prepare a kneaded product. Next, the kneaded product was extruded into a honeycomb shape having an outer diameter of 79 mm □, an opening of 4.28 mm, a partition wall thickness of 0.88 mm, and a length of 400 mm with a vacuum extrusion molding machine, and the molded product was dried at 60 ° C. for 48 hours. Baked at 530 ° C. for 3 hours and TiO in weight ratio 2 / V 2 O 5 A catalyst (a-1) having a composition of / GF / acid clay of 86/4/5/5 was prepared. Table 1 shows the properties of the catalyst (a-1).
[0026]
Example 1 <Preparation of Catalyst (a-2)>
A solution prepared by dissolving 1.28 kg of ammonium metavanadate with 0.64 kg of monoethanolamine was added to 21.4 kg of the titanium dioxide raw material (a) in Reference Example 1 and 0.19 kg of dipsite alumina hydrate, and then ammonia water was added. Then, the pH of this mixed slurry was set to 9, and water was further added to make the water content 38%. Thereafter, 1.25 kg of glass fiber (GF), 1.25 kg of acid clay, and 0.5 kg of polyethylene oxide were added, and the mixture was further kneaded and kneaded for 30 minutes to prepare a kneaded product. Next, the kneaded product was extruded into a honeycomb shape having an outer diameter of 79 mm □, an opening of 4.28 mm, a partition wall thickness of 0.88 mm, and a length of 400 mm with a vacuum extrusion molding machine, and the molded product was dried at 60 ° C. for 48 hours. Baked at 530 ° C. for 3 hours and TiO in weight ratio 2 / Al 2 O 3 / V 2 O 5 A catalyst (a-2) having a composition of / GF / acid clay was 85.5 / 0.5 / 4/5/5 was prepared. The properties of the catalyst (a-2) are shown in Table 1.
[0027]
Example 2 <Preparation of catalyst (a-3)>
A solution obtained by dissolving 1.28 kg of ammonium metavanadate with 0.64 kg of monoethanolamine was added to 20.25 kg of the titanium dioxide raw material (a) of Reference Example 1 and 1.92 kg of dipsite alumina hydrate, and then ammonia water was added. Then, the pH of this mixed slurry was set to 9, and water was further added to make the water content 38%. Thereafter, 1.25 kg of glass fiber (GF), 1.25 kg of acid clay, and 0.5 kg of polyethylene oxide were added, and the mixture was further kneaded and kneaded for 30 minutes to prepare a kneaded product. Next, the kneaded product was extruded into a honeycomb shape having an outer diameter of 79 mm □, an opening of 4.28 mm, a partition wall thickness of 0.88 mm, and a length of 400 mm with a vacuum extrusion molding machine, and the molded product was dried at 60 ° C. for 48 hours. Baked at 530 ° C. for 3 hours and TiO in weight ratio 2 / Al 2 O 3 / V 2 O 5 A catalyst (a-3) having a composition of / GF / acid clay of 81/5/4/5/5 was prepared. The properties of the catalyst (a-3) are shown in Table 1.
[0028]
Example 3 <Preparation of catalyst (a-4)>
A solution obtained by dissolving 1.28 kg of ammonium metavanadate with 0.64 kg of monoethanolamine was added to 19.00 kg of titanium dioxide raw material (a) in Reference Example 1 and 3.84 kg of dipsite alumina hydrate, and then ammonia water was added. Then, the pH of this mixed slurry was set to 9, and water was further added to make the water content 38%. Thereafter, 1.25 kg of glass fiber (GF), 1.25 kg of acid clay, and 0.5 kg of polyethylene oxide were added, and the mixture was further kneaded and kneaded for 30 minutes to prepare a kneaded product. Next, the kneaded product was extruded into a honeycomb shape having an outer diameter of 79 mm □, an opening of 4.28 mm, a partition wall thickness of 0.88 mm, and a length of 400 mm with a vacuum extrusion molding machine, and the molded product was dried at 60 ° C. for 48 hours. Baked at 530 ° C. for 3 hours and TiO in weight ratio 2 / Al 2 O 3 / V 2 O 5 A catalyst (a-4) having a composition of / GF / acid clay was 76/10/4/5/5 was prepared. Table 1 shows the properties of the catalyst (a-4).
[0029]
Comparative Example 2 <Catalyst Preparation (a-5)> (Case where the amount of alumina is too large)
A solution prepared by dissolving 1.28 kg of ammonium metavanadate with 0.64 kg of monoethanolamine was added to 16.50 kg of the titanium dioxide raw material (a) of Reference Example 1 and 7.67 kg of dipsite alumina hydrate, and then aqueous ammonia was added. In addition, the pH of the mixed slurry was adjusted to 9, and water was further added to a moisture content of 38%, followed by heating and kneading with a kneader for 25 minutes. Thereafter, 1.25 kg of glass fiber (GF), 1.25 kg of acid clay, and 0.5 kg of polyethylene oxide were added, and the mixture was further kneaded and kneaded for 30 minutes to prepare a kneaded product. Next, the kneaded product was extruded into a honeycomb shape having an outer diameter of 79 mm □, an opening of 4.28 mm, a partition wall thickness of 0.88 mm, and a length of 400 mm with a vacuum extrusion molding machine, and the molded product was dried at 60 ° C. for 48 hours. Baked at 530 ° C. for 3 hours and TiO in weight ratio 2 / Al 2 O 3 / V 2 O 5 A catalyst (a-5) having a composition of / GF / acid clay of 66/20/4/5/5 was prepared. The properties of the catalyst (a-5) are shown in Table 1.
[0030]
Comparative Example 3 <Catalyst Preparation (a-6)> (Alumina Hydrate not Used as Alumina Source)
A solution prepared by dissolving 1.28 kg of ammonium metavanadate with 0.64 kg of monoethanolamine was used to prepare 20.25 kg of titanium dioxide raw material (a) of Reference Example 1 and activated alumina (Al 2 O 3 ) Added to 1.25 kg, then ammonia water was added to adjust the pH of the mixed slurry to 9, and water was further added to a moisture content of 38%, followed by heating and kneading with a kneader for 25 minutes. Thereafter, 1.25 kg of glass fiber (GF), 1.25 kg of acid clay, and 0.5 kg of polyethylene oxide were added, and the mixture was further kneaded and kneaded for 30 minutes to prepare a kneaded product. Next, the kneaded product was extruded into a honeycomb shape having an outer diameter of 79 mm □, an opening of 4.28 mm, a partition wall thickness of 0.88 mm, and a length of 400 mm with a vacuum extrusion molding machine, and the molded product was dried at 60 ° C. for 48 hours. Baked at 530 ° C. for 3 hours and TiO in weight ratio 2 / Al 2 O 3 / V 2 O 5 A catalyst (a-6) having a composition of / GF / acid clay was 81/5/4/5/5 was prepared. The properties of the catalyst (a-6) are shown in Table 1.
[0031]
Example 4 <Preparation of Catalyst (b-1)>
A solution prepared by dissolving 1.28 kg of ammonium metavanadate with 0.64 kg of monoethanolamine was added to 20.25 kg of the titanium dioxide raw material (b) of Reference Example 2 and 1.92 kg of dipsite alumina hydrate, and then ammonia water was added thereto. The pH of the mixed slurry was adjusted to 9, and water was further added to a moisture content of 38%, followed by heating and kneading with a kneader for 25 minutes. Thereafter, 1.25 kg of glass fiber (GF), 1.25 kg of acid clay, and 0.5 kg of polyethylene oxide were added, and kneaded and further kneaded for 30 minutes to prepare a kneaded product. Next, the kneaded product was extruded into a honeycomb shape having an outer diameter of 79 mm □, an opening of 4.28 mm, a partition wall thickness of 0.88 mm, and a length of 400 mm with a vacuum extrusion molding machine, and the molded product was dried at 60 ° C. for 48 hours. Baked at 530 ° C. for 3 hours and TiO in weight ratio 2 / WO 3 / Al 2 O 3 / V 2 O 5 A catalyst (b-1) having a composition of / GF / acid clay of 72.9 / 8.1 / 5/4/5/5 was prepared. The properties of the catalyst (b-1) are shown in Table 1.
[0032]
Example 5 <Preparation of Catalyst (bc-1)>
A solution in which 1.28 kg of ammonium metavanadate was dissolved in 0.64 kg of monoethanolamine was used in 12.75 kg of the titanium dioxide raw material (b) of Reference Example 1, 7.50 kg of the titanium dioxide raw material (c) of Reference Example 2, and a dipsite-type alumina water The mixture was added to 1.92 kg, then aqueous ammonia was added to adjust the pH of the mixed slurry to 9, and water was further added to a moisture content of 38%, followed by heating and kneading with a kneader for 25 minutes. Thereafter, 1.25 kg of glass fiber (GF), 1.25 kg of acid clay, and 0.5 kg of polyethylene oxide were added, and kneaded and further kneaded for 30 minutes to prepare a kneaded product. Next, the kneaded product was extruded into a honeycomb shape having an outer diameter of 79 mm □, an opening of 4.28 mm, a partition wall thickness of 0.88 mm, and a length of 400 mm with a vacuum extrusion molding machine, and the molded product was dried at 60 ° C. for 48 hours. Baked at 530 ° C. for 3 hours and TiO in weight ratio 2 / WO 3 / SiO 2 / Al 2 O 3 / V 2 O 5 A catalyst (bc-1) having a composition of / GF / acid clay of 71.4 / 8.1 / 1.5 / 5/4/5/5 was prepared. Properties of the catalyst (bc-1) are shown in Table 1.
[0033]
Application example 1
Catalysts (a-2), (a-3), (a-4), (b-1) (bc-1) of Examples 1 to 5 and catalysts (a-1) of (Comparative Examples 1 to 3), ( Using a-5) and (a-6), a nitrogen oxide removing ability test, a vanadium pentoxide separation, and a scattering test were performed.
<Nitrogen oxide decomposition removal test>
A test sample cut from each honeycomb catalyst at a length of 300 mm and 5 × 5 was filled into a flow reactor, and the denitration rate was measured under the following conditions. The denitration rate was determined by the following equation by measuring the concentration of nitrogen oxide (NOx) in the gas before and after contacting the catalyst with a chemirmi-type nitrogen oxide analyzer.
Denitration rate (%) = [{NOx in non-contact gas (ppm) −NOx in gas after contact (ppm)} / NOx in non-contact gas (ppm)] × 100
[0034]
<Vanadium pentoxide separation and scattering test>
A test sample cut from each honeycomb catalyst at a length of 250 mm and 4 × 5 was filled in a flow reactor, and the separation and scattering amount of vanadium pentoxide was measured under the following conditions. After the test, vanadium pentoxide was separated from the inner wall of the flow reactor and the outlet of the flow reactor by washing the vanadium pentoxide adhering to the glass wool with 1 N oxalic acid. did. This was quantified with ICP as vanadium, converted into vanadium pentoxide, and separated and scattered.
[0035]
[Table 1]
The catalyst (a-1) of Comparative Example 1 has a very large amount of separation and scattering of vanadium pentoxide. 2 O 3 The catalyst of the example containing 0.5 to 10% by weight reduces the separation and scattering amount of vanadium pentoxide, but the nitrogen oxide removal (denitration) performance does not deteriorate so as to impede practical use. It was. However, the alumina hydrate 2 O 3 As a result, the catalyst (a-5) of Comparative Example 2 containing 20% by weight hardly lost the amount of vanadium pentoxide separated and scattered, but the denitration performance was extremely lowered. The denitration performance of the industrially used catalyst is preferably such that the denitration rate under the test conditions is 75% or more.
[0037]
Activated alumina (Al 2 O 3 The catalyst (a-6) of Comparative Example 3 in which 5% by weight was used had the same effect as that of (a-3) in suppressing the separation and scattering of vanadium pentoxide, but the denitration performance was extremely lowered.
[0038]
The catalyst (b-1) of Example 4 using the titanium dioxide raw material (b) is WO 3 Is contained in an amount of 8.1% by weight. 2 O 3 As compared with the catalyst (a-3) of Example 2 containing 5% by weight, the denitration performance was even higher.
Further, the catalyst (bc-1) of Example 5 to which 30% by weight of the titanium dioxide raw material (c) was added has an appropriate silicon dioxide content of 1.5% by weight, so that the catalyst of Comparative Example 1 ( Compared to a-1), it can be seen that the separation and scattering amount of vanadium pentoxide is reduced by about 70% and high denitration performance is maintained.
[0039]
【The invention's effect】
The catalyst of the present invention has an effect of suppressing separation and scattering of vanadium pentoxide in the catalyst while maintaining high catalytic activity such as nitrogen oxide decomposition and removal ability and chlorinated organic compound decomposition and removal ability. Air pollution due to harmful vanadium pentoxide is prevented.
Claims (5)
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| JP2003189044A JP2005021780A (en) | 2003-06-30 | 2003-06-30 | Method for producing exhaust gas treatment catalyst |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013031818A (en) * | 2011-08-03 | 2013-02-14 | Babcock Hitachi Kk | Denitration catalyst for ammonia catalytic reduction |
| JP2016093810A (en) * | 2009-12-15 | 2016-05-26 | クリスタル ユーエスエー インコーポレイテッドＣｒｉｓｔａｌ Ｕｓａ Ｉｎｃ． | Method of using captured material |
| JP2017508605A (en) * | 2014-01-23 | 2017-03-30 | ジョンソン、マッセイ、パブリック、リミテッド、カンパニーＪｏｈｎｓｏｎ Ｍａｔｔｈｅｙ Ｐｕｂｌｉｃ Ｌｉｍｉｔｅｄ Ｃｏｍｐａｎｙ | Catalytic converter |
-
2003
- 2003-06-30 JP JP2003189044A patent/JP2005021780A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016093810A (en) * | 2009-12-15 | 2016-05-26 | クリスタル ユーエスエー インコーポレイテッドＣｒｉｓｔａｌ Ｕｓａ Ｉｎｃ． | Method of using captured material |
| JP2013031818A (en) * | 2011-08-03 | 2013-02-14 | Babcock Hitachi Kk | Denitration catalyst for ammonia catalytic reduction |
| JP2017508605A (en) * | 2014-01-23 | 2017-03-30 | ジョンソン、マッセイ、パブリック、リミテッド、カンパニーＪｏｈｎｓｏｎ Ｍａｔｔｈｅｙ Ｐｕｂｌｉｃ Ｌｉｍｉｔｅｄ Ｃｏｍｐａｎｙ | Catalytic converter |
| US10300461B2 (en) | 2014-01-23 | 2019-05-28 | Johnson Matthey Public Limited Company | Catalytic converter |
| US11291975B2 (en) | 2014-01-23 | 2022-04-05 | Johnson Matthey Public Limited Company | Catalytic converter |
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