JP2007075774A - Catalyst for catalytically reducing and removing nitrogen oxide - Google Patents
Catalyst for catalytically reducing and removing nitrogen oxide Download PDFInfo
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- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 title claims abstract description 207
- 239000003054 catalyst Substances 0.000 title claims abstract description 167
- 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 55
- 229910052709 silver Inorganic materials 0.000 claims abstract description 53
- 239000004332 silver Substances 0.000 claims abstract description 53
- 239000007789 gas Substances 0.000 claims abstract description 36
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 30
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 28
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000001301 oxygen Substances 0.000 claims abstract description 28
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 25
- 239000002245 particle Substances 0.000 claims abstract description 24
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 claims abstract description 23
- 229910052733 gallium Inorganic materials 0.000 claims abstract description 23
- 229910052751 metal Inorganic materials 0.000 claims abstract description 22
- 239000002184 metal Substances 0.000 claims abstract description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 22
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 15
- 239000010941 cobalt Substances 0.000 claims abstract description 15
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 15
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 15
- 239000010937 tungsten Substances 0.000 claims abstract description 15
- 229910052738 indium Inorganic materials 0.000 claims abstract description 14
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 claims abstract description 14
- 229910052742 iron Inorganic materials 0.000 claims abstract description 13
- 230000001590 oxidative effect Effects 0.000 claims description 10
- 238000002156 mixing Methods 0.000 abstract description 15
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 52
- 238000002360 preparation method Methods 0.000 description 26
- 238000011156 evaluation Methods 0.000 description 24
- 230000000694 effects Effects 0.000 description 22
- 238000006722 reduction reaction Methods 0.000 description 21
- 238000000034 method Methods 0.000 description 20
- 230000000052 comparative effect Effects 0.000 description 16
- 229930195733 hydrocarbon Natural products 0.000 description 16
- 150000002430 hydrocarbons Chemical class 0.000 description 16
- 238000006243 chemical reaction Methods 0.000 description 15
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 12
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 12
- 239000003153 chemical reaction reagent Substances 0.000 description 9
- 239000000126 substance Substances 0.000 description 9
- 238000002485 combustion reaction Methods 0.000 description 7
- 239000004215 Carbon black (E152) Substances 0.000 description 6
- 229910021529 ammonia Inorganic materials 0.000 description 6
- 229910002091 carbon monoxide Inorganic materials 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- 229910001961 silver nitrate Inorganic materials 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 4
- 239000004202 carbamide Substances 0.000 description 4
- DIOQZVSQGTUSAI-UHFFFAOYSA-N decane Chemical compound CCCCCCCCCC DIOQZVSQGTUSAI-UHFFFAOYSA-N 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 3
- -1 alkoxide compound Chemical class 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 239000000470 constituent Substances 0.000 description 3
- 239000012153 distilled water Substances 0.000 description 3
- 239000000446 fuel Substances 0.000 description 3
- 238000005470 impregnation Methods 0.000 description 3
- 150000002736 metal compounds Chemical class 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 238000003980 solgel method Methods 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 238000010531 catalytic reduction reaction Methods 0.000 description 2
- 239000002283 diesel fuel Substances 0.000 description 2
- CHPZKNULDCNCBW-UHFFFAOYSA-N gallium nitrate Chemical compound [Ga+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O CHPZKNULDCNCBW-UHFFFAOYSA-N 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 239000012495 reaction gas Substances 0.000 description 2
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 2
- 229910052815 sulfur oxide Inorganic materials 0.000 description 2
- 101710134784 Agnoprotein Proteins 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910002554 Fe(NO3)3·9H2O Inorganic materials 0.000 description 1
- 241000264877 Hippospongia communis Species 0.000 description 1
- OWIKHYCFFJSOEH-UHFFFAOYSA-N Isocyanic acid Chemical compound N=C=O OWIKHYCFFJSOEH-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- XURCIPRUUASYLR-UHFFFAOYSA-N Omeprazole sulfide Chemical compound N=1C2=CC(OC)=CC=C2NC=1SCC1=NC=C(C)C(OC)=C1C XURCIPRUUASYLR-UHFFFAOYSA-N 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- XLJMAIOERFSOGZ-UHFFFAOYSA-N anhydrous cyanic acid Natural products OC#N XLJMAIOERFSOGZ-UHFFFAOYSA-N 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 1
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 1
- 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 1
- 238000010908 decantation Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 150000004665 fatty acids Chemical class 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 229940044658 gallium nitrate Drugs 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 239000005457 ice water Substances 0.000 description 1
- MVFCKEFYUDZOCX-UHFFFAOYSA-N iron(2+);dinitrate Chemical compound [Fe+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MVFCKEFYUDZOCX-UHFFFAOYSA-N 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 239000006069 physical mixture Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229910001924 platinum group oxide Inorganic materials 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000006228 supernatant Substances 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- WOZZOSDBXABUFO-UHFFFAOYSA-N tri(butan-2-yloxy)alumane Chemical compound [Al+3].CCC(C)[O-].CCC(C)[O-].CCC(C)[O-] WOZZOSDBXABUFO-UHFFFAOYSA-N 0.000 description 1
- 231100000925 very toxic Toxicity 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
- 239000001993 wax Substances 0.000 description 1
Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Landscapes
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Abstract
Description
本発明は、過剰酸素が存在する酸化雰囲気下で、排ガス中に含まれる、あるいは少量添加した炭化水素を還元剤として、該排ガス中の窒素酸化物を効率よく還元除去する触媒に関する。 The present invention relates to a catalyst that efficiently reduces and removes nitrogen oxides in exhaust gas using hydrocarbons contained in exhaust gas or added in a small amount as a reducing agent in an oxidizing atmosphere containing excess oxygen.
種々の内燃機関や燃焼器より排出される窒素酸化物(以下、「NOx」と記すこともある）は、人体に悪影響を及ぼすのみならず、光化学スモッグや酸性雨の発生原因ともなり得るため、環境対策上その低減が急務となっている。
この排ガス中のNOx を除去する方法として、触媒を用いて低減する触媒後処理技術が、既に幾つか実用化されている。例えば、（イ）ガソリン自動車における三元触媒法や、（ロ）ボイラー等の大型設備排出源からの排ガスについてのアンモニアによる選択的接触還元、さらには（ハ）リーンバーンガソリン車からの排ガスについては、エンジンシステム上でリッチとリーンの雰囲気を短期間に交互に変化させ、リーン条件下でNOを触媒内に吸蔵し、その後のリッチ条件下で排ガス中の一酸化炭素や未燃炭化水素等を還元剤としてNOを還元する吸蔵還元法（特許文献１参照）や、（ニ）ディーゼル車排ガスに関しては尿素を還元剤とする選択的接触還元などが挙げられる。
また、（ホ）酸化性雰囲気において炭化水素類を還元剤としてNOxを還元する方法が提案されており、銀、コバルトなどの金属や白金などの貴金属を含むアルミナなどの金属酸化物や種々の金属を担持させたゼオライトが触媒として用いられる（非特許文献１、特許文献２〜４参照）。
Nitrogen oxides emitted from various internal combustion engines and combustors (hereinafter sometimes referred to as “NOx”) not only adversely affect the human body, but can also cause photochemical smog and acid rain, It is an urgent need to reduce it for environmental measures.
As a method for removing NOx in the exhaust gas, several catalyst post-treatment techniques for reducing using NOx have already been put into practical use. For example, (a) three-way catalyst method in gasoline automobiles, (b) selective catalytic reduction with ammonia for exhaust gas from large equipment such as boilers, and (c) exhaust gas from lean burn gasoline cars In the engine system, the atmosphere of rich and lean is alternately changed in a short period of time, NO is occluded in the catalyst under the lean condition, and carbon monoxide and unburned hydrocarbons in the exhaust gas are then stored under the rich condition. As a reducing agent, an occlusion reduction method for reducing NO (refer to Patent Document 1), and (d) selective catalytic reduction using urea as a reducing agent for diesel vehicle exhaust gas may be used.
In addition, (e) a method for reducing NOx using hydrocarbons as a reducing agent in an oxidizing atmosphere has been proposed. Metal oxides such as alumina including metals such as silver and cobalt and noble metals such as platinum and various metals have been proposed. Is used as a catalyst (see Non-Patent Document 1 and Patent Documents 2 to 4).
上記（イ）の方法は、自動車の燃焼排ガス中に含まれる炭化水素成分と一酸化炭素を白金族を含有する触媒によって水と二酸化炭素とし、同時にNOxを還元して窒素(N2)に変換するものである。しかし、この方法では、排ガス中の酸素とNOxに含まれる酸素の合計量と、炭化水素成分および一酸化炭素が酸化されるのに必要となる酸素量とが化学量論的に等しくなるように酸素濃度を調整する必要があり、ディーゼルエンジンやリーンバーンエンジンのように排ガス中に多量の酸素を含む酸素過剰雰囲気下では、原理的に適用が不可能という問題がある。
また、（ロ）のアンモニアを還元剤として用いる場合は、酸素雰囲気においてもNOxを還元浄化できるが、アンモニアは非常に有毒であり、その取り扱いは容易でなく、従って小型の排ガス発生源、特に移動型発生源に適用することは技術的に困難で、経済性も良くない。さらに、アンモニア代替還元剤として、加水分解することで容易にアンモニアを発生することができる尿素を還元剤として使用する（ニ）の方法は、大型ディーゼル車への実用化が達成されているが、尿素を供給するためのインフラ整備など、未だに多くの課題が残されている。
上記（ハ）の方法では、有毒なアンモニアを使用することなく、かつ尿素のように外部供給の必要性もなく、過剰酸素雰囲気下でNOxを無害化できる方法であるが、リーン／リッチ条件を周期的に変動させるために複雑な運転制御を必要とする。また、塩基性物質であるNOx吸蔵剤は硫黄酸化物に対する耐久性が低く、硫黄酸化物により失活した触媒を再生するために周期的に燃料リッチな条件で運転する必要があり、希薄燃焼エンジンの特徴である低燃費性を犠牲にしている。
In the method (a) above, hydrocarbon components and carbon monoxide contained in automobile combustion exhaust gas are converted into water and carbon dioxide by a catalyst containing a platinum group, and NOx is simultaneously reduced to nitrogen (N 2 ). To do. However, with this method, the total amount of oxygen in the exhaust gas and oxygen contained in NOx is stoichiometrically equal to the amount of oxygen required to oxidize the hydrocarbon components and carbon monoxide. It is necessary to adjust the oxygen concentration, and there is a problem that it cannot be applied in principle under an oxygen-excess atmosphere containing a large amount of oxygen in exhaust gas, such as a diesel engine or lean burn engine.
In addition, when (b) ammonia is used as a reducing agent, NOx can be reduced and purified even in an oxygen atmosphere, but ammonia is very toxic and not easy to handle. It is technically difficult to apply to the mold source and is not economical. Furthermore, the method of (d) using urea, which can easily generate ammonia by hydrolysis as a reducing agent instead of ammonia, has been put to practical use for large diesel vehicles. Many issues still remain, such as infrastructure development to supply urea.
In the method (c), NOx can be detoxified in an excess oxygen atmosphere without using toxic ammonia and without the need for external supply like urea. In order to change periodically, complicated operation control is required. In addition, NOx occlusion agent, which is a basic substance, has low durability against sulfur oxides, and it is necessary to periodically operate under fuel-rich conditions to regenerate the catalyst deactivated by sulfur oxides. This is at the expense of low fuel consumption, which is a characteristic of.
一方、（ホ）については、酸素雰囲気においてもNOxを還元除去できる新しい方法として注目され、1990年以降国内外を問わず盛んに研究が行われてきており、これまでに炭化水素類を還元剤としてNOxを浄化できる触媒が多数提案されている。その中で、アルミナに担持した銀触媒は、NOx浄化率が高く、しかも活性な温度域が広い特徴を持っており、基礎研究から実用化研究まで盛んに検討されている。最近、炭化水素類を還元剤とするNO選択還元において、アルミナ担持銀触媒のNOx浄化率を向上させるために、反応ガスに少量の水素を添加する方法が提案された（例えば、Chem. Lett., (2000) 294）。この方法では水素を添加しない場合と比較して大幅なNOx除去率の向上が達成できるが、水素供給源の確保や自動車などの移動発生源では水素の保管スペースなど、実用的にはあまり適さない方法である。
そこで、触媒の特性に排ガス条件を最適化するのではなく、アルミナ担持銀触媒を改良することでNOx浄化率を向上させることが望まれている。
本発明は以上の（イ）〜（ホ）に存在する各種の問題を解決するためになされたもので、ディーゼル機関の排ガスをはじめ、種々のリーンバーンエンジン、ボイラなどから発生する水蒸気および高濃度の酸素を含有する排ガス中の窒素酸化物を効率良く還元除去する触媒を提供することを目的としている。
On the other hand, (e) has attracted attention as a new method capable of reducing and removing NOx even in an oxygen atmosphere, and has been actively studied both in Japan and overseas since 1990. To date, hydrocarbons have been reduced to reducing agents. Many catalysts that can purify NOx have been proposed. Among them, the silver catalyst supported on alumina has a high NOx purification rate and a wide active temperature range, and has been actively studied from basic research to practical research. Recently, in NO selective reduction using hydrocarbons as a reducing agent, a method of adding a small amount of hydrogen to a reaction gas has been proposed in order to improve the NOx purification rate of an alumina-supported silver catalyst (for example, Chem. Lett. , (2000) 294). This method can achieve a significant improvement in NOx removal rate compared to the case where hydrogen is not added, but it is not very suitable for practical use, such as securing a hydrogen supply source or hydrogen storage space for mobile sources such as automobiles. Is the method.
Therefore, it is desired to improve the NOx purification rate by improving the alumina-supported silver catalyst rather than optimizing the exhaust gas conditions for the characteristics of the catalyst.
The present invention was made in order to solve the various problems existing in the above (a) to (e), and water vapor and high concentration generated from exhaust gas from various diesel engines, various lean burn engines, boilers, and the like. An object of the present invention is to provide a catalyst that efficiently reduces and removes nitrogen oxides in exhaust gas containing oxygen.
本発明者等は、上記の従来技術に存在する問題を解決するために、アルミナに担持した銀触媒ではイソシアン酸など含窒素・含炭素化合物が生成する（例えば、Appl.Catal.B 13 (1997) 157）ことに着目し、これらの化合物を窒素へと分解する触媒を混合してNOx除去率を向上させることを考えた。鋭意研究を重ねた結果、アルミナに銀を含有する触媒とアルミナ、もしくは金属を含有するアルミナを物理的に混合した触媒を用いることにより、NOxをきわめて効率良く除去できることを見出し、本発明を完成するに至った。
すなわち、本発明のNOxの除去触媒は、過剰の酸素が存在する酸化雰囲気中、かつ水蒸気共存下においても、炭化水素の存在下において、窒素酸化物を還元除去する触媒であって、該触媒が、アルミナに銀を含有する触媒とアルミナ、もしくはガリウム、タングステン、インジウム、コバルト、鉄よりなる群から選ばれる少なくとも１種の金属を含有するアルミナを物理的に混合した触媒であることを特徴とする。
すなわち、本願発明は、アルミナに銀を含有する触媒粒子(A)と、アルミナ粒子及び／又はガリウム、タングステン、インジウム、コバルト、鉄よりなる群から選ばれる少なくとも１種の金属を含有するアルミナ粒子(B)を物理的に混合した、水蒸気と過剰の酸素が存在する酸化雰囲気中で、還元剤を使用して、窒素酸化物を選択的に還元除去するための触媒である。
また、本願発明は、アルミナに銀を含有する触媒粒子(A)とアルミナ、もしくはガリウム、タングステン、インジウム、コバルト、鉄よりなる群から選ばれる少なくとも１種の金属を含有するアルミナ粒子(B)の比率(A/B)が1/3〜3/1とすることができる。
さらに、本願発明は、触媒粒子(A) とアルミナ粒子(B)の粒子径を、５〜１００μｍとすることができる。
また、本願発明は、水蒸気と過剰の酸素が存在する酸化雰囲気がジーゼルエンジンからの排気ガスであり、還元剤が軽油であり、窒素酸化物がディーゼルエンジンからの窒素酸化物である場合を含むものであり、本願発明の触媒を、ディーゼルエンジンからの排気ガスの浄化のために用いることを目的の一つとしている。
In order to solve the above problems existing in the prior art, the present inventors produce nitrogen-containing and carbon-containing compounds such as isocyanic acid with silver catalysts supported on alumina (for example, Appl. Catal. B 13 (1997). ) 157), it was considered to improve the NOx removal rate by mixing a catalyst that decomposes these compounds into nitrogen. As a result of intensive research, it has been found that NOx can be removed very efficiently by using a catalyst in which alumina and a catalyst containing silver or alumina containing a metal are physically mixed, thereby completing the present invention. It came to.
That is, the NOx removal catalyst of the present invention is a catalyst that reduces and removes nitrogen oxides in the presence of hydrocarbons in the presence of hydrocarbons even in the presence of excess oxygen and in the presence of water vapor. The catalyst is characterized by physically mixing a catalyst containing silver in alumina and alumina, or alumina containing at least one metal selected from the group consisting of gallium, tungsten, indium, cobalt, and iron. .
That is, the present invention provides catalyst particles (A) containing silver in alumina and alumina particles and / or alumina particles containing at least one metal selected from the group consisting of gallium, tungsten, indium, cobalt and iron ( A catalyst for selectively reducing and removing nitrogen oxides using a reducing agent in an oxidizing atmosphere in which water vapor and excess oxygen exist, in which B) is physically mixed.
The present invention also relates to catalyst particles (A) containing silver in alumina and alumina particles (B) containing at least one metal selected from the group consisting of alumina, gallium, tungsten, indium, cobalt and iron. The ratio (A / B) can be 1/3 to 3/1.
Furthermore, in the present invention, the particle diameters of the catalyst particles (A) and the alumina particles (B) can be 5 to 100 μm.
The present invention also includes a case where the oxidizing atmosphere in which water vapor and excess oxygen exist is exhaust gas from a diesel engine, the reducing agent is light oil, and the nitrogen oxide is nitrogen oxide from a diesel engine. Therefore, an object of the present invention is to use the catalyst of the present invention for purifying exhaust gas from a diesel engine.
本発明の触媒によれば、水蒸気および酸素が過剰に存在する酸化雰囲気下で、炭化水素を還元剤として用いることで、効率的に排ガス中の窒素酸化物を除去することができる。このように、本発明の触媒は、ディーゼル機関やリーンバーンガソリンエンジンをはじめ、種々の内燃機関や燃焼器より排出される排ガス中に含まれる窒素酸化物を効率よく除去することができ、工業的価値は極めて高いものである。 According to the catalyst of the present invention, nitrogen oxides in exhaust gas can be efficiently removed by using hydrocarbon as a reducing agent in an oxidizing atmosphere in which water vapor and oxygen are excessively present. As described above, the catalyst of the present invention can efficiently remove nitrogen oxides contained in exhaust gas discharged from various internal combustion engines and combustors, including diesel engines and lean burn gasoline engines. The value is extremely high.
以下、本発明の詳細を説明する。
本発明の触媒の構成主成分であるアルミナ(Al2O3)は耐熱、耐水性な金属酸化物であり、従来公知の方法やアルコキシド化合物を用いるゾルゲル法など、いかなる方法で合成されたものを使用してもよい。
本発明の触媒は、銀を含有するアルミナとアルミナ、もしくはガリウム、タングステン、インジウム、コバルト、鉄よりなる群から選ばれる少なくとも１種の金属を含有するアルミナと物理的に混合したものである。アルミナ担持銀触媒における銀の含有量は、銀の金属形態の換算で、触媒の0.1〜5wt%、好ましくは2〜4wt%である。もう一方の触媒である金属を含有するアルミナにおける金属成分の含有量は触媒基準、金属換算で1〜5wt%とすることが望ましい。
アルミナへの銀あるいは上記5種類の金属の含有方法は、金属化合物の水溶液を用いて、従来公知の含浸や沈着法などで行うことができる。
例えば、アルミナへの銀もしくは上記5種類のいずれかの金属の含有は、銀もしくは上記5種類のいずれかの金属化合物の水溶液にアルミナを浸漬して、水洗、乾燥した後、空気中で焼成することにより行うことができる。このときの銀もしくは上記5種類のいずれかの金属化合物は、水に可溶な化合物であればいずれのものでもよいが、通常は残存陰イオンを空気中の焼成処理によって比較的低温で分解除去される硝酸塩を用いる。含浸の温度は室温〜100℃で、時間は1〜24時間で行う。一般的には80℃で1〜3時間である。含浸後の触媒は、通常、乾燥後、空気中で焼成する。
Details of the present invention will be described below.
Alumina (Al 2 O 3 ), which is a constituent component of the catalyst of the present invention, is a heat-resistant and water-resistant metal oxide, and can be synthesized by any method such as a conventionally known method or a sol-gel method using an alkoxide compound. May be used.
The catalyst of the present invention is a physical mixture of alumina containing silver and alumina, or alumina containing at least one metal selected from the group consisting of gallium, tungsten, indium, cobalt, and iron. The silver content in the alumina-supported silver catalyst is 0.1 to 5 wt%, preferably 2 to 4 wt% of the catalyst in terms of silver metal form. The content of the metal component in the alumina containing the metal which is the other catalyst is preferably 1 to 5 wt% in terms of catalyst and metal.
The method of containing silver or the above five kinds of metals in alumina can be carried out by a conventionally known impregnation or deposition method using an aqueous solution of a metal compound.
For example, the inclusion of silver or any of the above five metals in alumina can be achieved by immersing the alumina in an aqueous solution of silver or any of the above five metal compounds, washing with water, drying, and then firing in air. Can be done. At this time, the silver or any of the above five metal compounds may be any compound that is soluble in water, but usually the residual anions are decomposed and removed at a relatively low temperature by a baking treatment in air. Nitrate is used. The impregnation temperature is room temperature to 100 ° C., and the time is 1 to 24 hours. Generally, it is 1-3 hours at 80 ° C. The impregnated catalyst is usually dried and then calcined in air.
また、銀を含有するアルミナとアルミナ、もしくは金属を含有するアルミナとの物理混合は、粉末を均一になるまで振り混ぜる方法、乳鉢等で磨り潰して混合する方法などで行うことができる。銀を含有するアルミナ(A)とアルミナ、もしくは金属を含有するアルミナ(B)との物理混合における比率(A/B)は、重量比で1/3〜3/1である。この比率よりも高くても低くても、物理混合をしたことの効果は得られない。
本発明の触媒は、粉状、粒体状、ペレット状、ハニカム状などで使用することができ、その形状、構造を特定するものではない。触媒を成形して使用する場合には、成形時に通常使用される粘結剤すなわちポリビニルアルコールなど、あるいは滑剤すなわち黒鉛、ワックス、脂肪酸類、カーボンワックスなどを使用することもできる。
本発明の触媒を用いた基本的な反応は、酸素存在下、窒素酸化物（NOx）として一酸化窒素（NO）、炭化水素としてn-デカン（C10H22）をそれぞれ例に採れば、（化１）および（化２）に示す反応式により進行すると推測される。
（化１） 62NO ＋ 2C10H22 → 31N2 ＋ 20CO2 ＋ 22H2O
（化２） 31O2 ＋ C10H22 → 20CO2 ＋ 22H2O
すなわち、（化１）でNOをN２にまで還元させるには、C10H22がNOによってH２OとCO2にまで酸化されることが必要であり、C10H22の酸化が進行しなければ、NOのN２への還元も進行しない。
一方、（化２）でC10H22の酸素酸化ばかりが進むと、C10H22は（化１）の反応に関与しなくなり、その結果としてNOのN２への還元率も低下する。
したがって、NOを高い割合で還元するには、NOの還元剤であるC10H22（以下、「還元剤」ということもある）が高濃度に存在する酸素よりも低濃度のNOと選択的に反応する触媒機能が必要となる。
このような還元剤の適度な酸化を促すために、本発明の触媒は有効に作用するものと考えられる。なお、本発明の触媒によるNOの還元除去反応において、還元生成物の殆どはN２であり、極く僅かにN２Oの生成が認められるだけである。
The physical mixing of silver-containing alumina and alumina or metal-containing alumina can be carried out by a method of shaking the powder until uniform, a method of grinding and mixing with a mortar or the like, and the like. The ratio (A / B) in the physical mixing of the alumina containing silver (A) and the alumina or the alumina containing metal (B) is 1/3 to 3/1 by weight. Even if it is higher or lower than this ratio, the effect of physical mixing cannot be obtained.
The catalyst of the present invention can be used in the form of powder, granules, pellets, honeycombs, etc., and its shape and structure are not specified. When the catalyst is molded and used, a binder that is usually used at the time of molding, that is, polyvinyl alcohol, or the like, or a lubricant, that is, graphite, wax, fatty acids, carbon wax, or the like can be used.
In the basic reaction using the catalyst of the present invention, in the presence of oxygen, nitric oxide (NO) as nitrogen oxide (NOx) and n-decane (C 10 H 22 ) as hydrocarbons are taken as examples. It is presumed that the reaction proceeds according to the reaction formulas shown in (Chemical Formula 1) and (Chemical Formula 2).
(Chemical formula 1) 62NO + 2C 10 H 22 → 31N 2 + 20CO 2 + 22H 2 O
(Chemical formula 2) 31O 2 + C 10 H 22 → 20CO 2 + 22H 2 O
That, in order to reduce NO to the N 2 by (Formula 1), it is necessary to C 10 H 22 is oxidized to between H 2 O and CO 2 by NO, oxidation proceeds in C 10 H 22 if you do not, it does not proceed even reduction to N 2 of nO.
On the other hand, when only oxygen oxidation of C 10 H 22 advances by (reduction 2), C 10 H 22 no longer participate in the reaction formula 1, also decreases the reduction rate of the resulting NO into N 2.
Therefore, to reduce NO at a high rate, C 10 H 22 (hereinafter sometimes referred to as “reducing agent”), which is a reducing agent for NO, is selectively used with NO at a lower concentration than oxygen present at a higher concentration. A catalytic function is required to react with the above.
In order to promote appropriate oxidation of such a reducing agent, the catalyst of the present invention is considered to work effectively. In the NO reduction reaction by the catalyst of the present invention, most of the reduction product is N 2 , and only a slight amount of N 2 O is observed.
本発明において、処理対象となるNOx含有ガスとしては、ディーゼル自動車や定置式ディーゼル機関などのディーゼル排ガスをはじめ、硝酸製造設備、各種燃焼設備などの水蒸気および高濃度の酸素を含有する排ガスを挙げることができる。これら排ガス中のNOxの除去は、上記した本発明の触媒に、還元剤としての炭化水素の存在下で、排ガスを接触させることにより行う。ここで、酸化雰囲気とは、排ガス中に含まれる一酸化炭素、水素、炭化水素類などの還元剤と、本発明の方法において必要に応じて添加される還元剤を完全に酸化して水と二酸化炭素に変換するのに必要な酸素量よりも過剰な酸素が含まれている雰囲気を言う。したがって、例えば、自動車などの内燃機関から排出される排ガスの場合には、酸素が過剰に存在する空燃比が大きい状態（リーン領域）のものであり、本発明の触媒を用いてNOxの除去を有効に行うことができる。
このような酸化雰囲気において、上記した本発明における触媒は、還元剤と酸素との反応（化２）よりも、（化１）に示すようなNOを選択的に還元する反応を優先的に促進させて、NOxを還元除去する。
NOxを還元除去する還元剤としては、排ガス中に残存するものでも良いが、（化１）に示す反応を促進させるのに必要な量よりも不足している場合には、外部より添加する必要がある。存在させる炭化水素の量は、特に制限されず、例えば要求されるNOx除去率が低い場合には、NOxの還元除去に必要な理論量より少なくてよい場合がある。ただし、必要な理論量より過剰とした方が還元反応はより進行されるので、一般的には過剰に添加するのが好ましい。通常は、NOxの還元除去に必要な理論量の約1.2〜20倍量の過剰、好ましくは約1.5〜15倍量過剰に存在させる。
In the present invention, the NOx-containing gas to be treated includes exhaust gas containing water vapor and high concentration oxygen such as diesel exhaust gas such as diesel automobiles and stationary diesel engines, nitric acid production equipment, various combustion equipment, etc. Can do. Removal of NOx in the exhaust gas is performed by bringing the exhaust gas into contact with the above-described catalyst of the present invention in the presence of hydrocarbon as a reducing agent. Here, the oxidizing atmosphere means that the reducing agent such as carbon monoxide, hydrogen, hydrocarbons, etc. contained in the exhaust gas and the reducing agent added as necessary in the method of the present invention are completely oxidized to water. An atmosphere that contains oxygen in excess of the amount of oxygen required to convert to carbon dioxide. Therefore, for example, in the case of exhaust gas discharged from an internal combustion engine such as an automobile, it is in a state where the air-fuel ratio in which oxygen is excessively present is large (lean region), and NOx removal is performed using the catalyst of the present invention. It can be done effectively.
In such an oxidizing atmosphere, the catalyst according to the present invention described above preferentially promotes the reaction for selectively reducing NO as shown in (Chemical Formula 1) rather than the reaction between the reducing agent and oxygen (Chemical Formula 2). Then, NOx is reduced and removed.
As a reducing agent for reducing and removing NOx, it may remain in the exhaust gas. However, if the amount is insufficient to promote the reaction shown in (Chemical Formula 1), it must be added from the outside. There is. The amount of hydrocarbon to be present is not particularly limited. For example, when the required NOx removal rate is low, it may be less than the theoretical amount necessary for the reduction and removal of NOx. However, since the reduction reaction proceeds more when the amount is larger than the required theoretical amount, it is generally preferable to add the amount excessively. Usually, it is present in an excess of about 1.2 to 20 times the theoretical amount required for reduction removal of NOx, preferably in an excess of about 1.5 to 15 times the theoretical amount.
本発明の触媒を用いたNOx還元除去反応は、本発明の触媒を配置した反応器内に、水蒸気が存在する酸化性雰囲気中で、炭化水素を存在させて、NOx含有排ガスを通過させることにより行う。このときの反応温度は、本発明における物理混合触媒の混合割合や金属の含有率、炭化水素類の種類により異なるが、排ガスの温度に近い温度が、排ガスの加熱設備などを必要としないので好ましく、一般には、約100〜800℃、特に約200〜600℃の範囲が適している。反応圧力は、特に制限されず、加圧下でも減圧下でも反応は進むが、通常の排気圧で排ガスを触媒層へ導入して、反応を進行させるのが便利である。また、ガス空間速度(GHSV)は、触媒の種類、他の反応条件、必要なNOx除去率等で決まり、特に制限はないが、概して、約500〜200000h-1、好ましくは約1000〜100000h-1の範囲が適している。なお、本発明の触媒を内燃機関からの排ガス処理に用いる場合、排気マニホールドの下流に配置するのが好ましい。
本発明で用いる触媒粒子(A) とアルミナ粒子(B)の粒子径は、通常５〜１００μｍであり、とくに１０〜５０μｍ程度のものが好ましく用いられる。
以下に、実施例を挙げて本発明を説明するが、本発明は、これらの実施例に限定されるものではない。
NOx reduction and removal reaction using the catalyst of the present invention is carried out by passing hydrocarbons and passing NOx-containing exhaust gas in an oxidizing atmosphere in which steam is present in a reactor in which the catalyst of the present invention is arranged. Do. The reaction temperature at this time varies depending on the mixing ratio of the physical mixed catalyst, the metal content, and the type of hydrocarbon in the present invention, but a temperature close to the temperature of the exhaust gas is preferable because it does not require heating equipment for the exhaust gas. Generally, a range of about 100-800 ° C, particularly about 200-600 ° C is suitable. The reaction pressure is not particularly limited, and the reaction proceeds either under pressure or under reduced pressure, but it is convenient to introduce the exhaust gas into the catalyst layer at normal exhaust pressure to advance the reaction. Further, a gas hourly space velocity (GHSV) is, the kind of the catalyst, other reaction conditions, depends on the required NOx removal rate and the like is not particularly limited, generally, about 500～200000H -1, preferably about 1000～100000H - A range of 1 is suitable. In addition, when using the catalyst of this invention for the waste gas treatment from an internal combustion engine, it is preferable to arrange | position downstream of an exhaust manifold.
The particle diameters of the catalyst particles (A) and alumina particles (B) used in the present invention are usually 5 to 100 μm, and those having a particle size of about 10 to 50 μm are preferably used.
EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.
（実施例で用いる触媒構成成分及び触媒の調整）
〔触媒構成成分の調製〕
・ゾルゲル法によるアルミナの調製
アルミニウムs-ブトキシド (Al(OC4H9)4) 50gを、氷水で冷却した蒸留水2000mlに滴下して加水分解することにより沈殿を生成させ、撹拌翼を使用して2時間攪拌を続けた。生成した沈殿をデカンテーションにより上澄み液から分離した後、得られた沈殿を蒸留水を使用して洗浄した。得られた沈殿を空気中110℃で一昼夜乾燥後、空気中400℃で5時間焼成した。得られた粉末を磨砕してふるいにかけ、５０μｍ以下の粒径のものを使用した。
・アルミナ担持銀触媒［A］の調製
上記アルミナへの銀の担持は含浸法により行った。硝酸銀（AgNO３） 0.33gを蒸留水 20mlに溶解した水溶液に、上記のアルミナ 5gを加え、80℃に保温したホットプレート上で撹拌しながら余分な水分を除去した後、110℃で一昼夜乾燥後、空気中600℃で5時間焼成して、アルミナ担持銀触媒［Ａ］を得た。このとき触媒に対する銀の含有量は、銀金属（Ag）換算で約4wt%であった。
・アルミナ担持銀触媒［Ｂ］の調製
ゾルゲル法で調製したアルミナを水沢化学社製アルミナ（商品名”GB-45”、190m2/g）に代えた以外は、上記、アルミナ担持銀触媒［Ａ］と同様にして調製し、アルミナ担持銀触媒［Ｂ］を得た。
・アルミナ担持ガリウム触媒の調製
硝酸銀の代わりに硝酸ガリウム(Ga(NO３)３・xH２O) 1.09gを用いた以外は上記、アルミナ担持銀触媒［Ａ］と同様にして調製し、アルミナ担持ガリウム触媒を得た。このとき触媒に対するガリウムの含有量は、ガリウム金属（Ga）換算で約4wt%であった。
・アルミナ担持タングステン触媒の調製
硝酸銀の代わりにパラタングステン酸アンモニウム(5(NH4)2O・13WO3・5H２O) 0.30gを用いた以外は上記、アルミナ担持銀触媒［Ａ］と同様にして調製し、アルミナ担持タングステン触媒を得た。このとき触媒に対するタングステンの含有量は、タングステン金属（W）換算で約4wt%であった。
・アルミナ担持インジウム触媒の調製
硝酸銀の代わりに硝酸インジウム(In(NO３)３・3H２O) 0.64gを用いた以外は上記、アルミナ担持銀触媒［Ａ］と同様にして調製し、アルミナ担持インジウム触媒を得た。このとき触媒に対するインジウムの含有量は、インジウム金属（In）換算で約4wt%であった。
・アルミナ担持コバルト触媒の調製
硝酸銀の代わりに硝酸コバルト(Co(NO３)2・6H２O) 1.03gを用いた以外は上記、アルミナ担持銀触媒［Ａ］と同様にして調製し、アルミナ担持コバルト触媒を得た。このとき触媒に対するコバルトの含有量は、コバルト金属（Co）換算で約4wt%であった。
・アルミナ担持鉄触媒の調製
硝酸銀の代わりに硝酸鉄(Fe(NO３)3・9H２O) 1.51gを用いた以外は上記、アルミナ担持銀触媒［Ａ］と同様にして調製し、アルミナ担持鉄触媒を得た。このとき触媒に対する鉄の含有量は、鉄金属（Fe）換算で約4wt%であった。
〔触媒活性評価〕
上記のようにして得られた本発明の触媒0.04gを常圧流通式反応装置に充填し、約500ppmの一酸化窒素（以下、「NO」と記す）、約10vol%の酸素、約300ppmのn-デカンおよび約6vol%のH2Oを含むヘリウムバランスの模擬排ガスを、毎分90mlの流速(SV=75000h-1に相当)で流して反応を行った。水分は、マイクロプランジャーポンプを用いて反応管の加温部に水を添加し、水蒸気として導入した。反応ガスの分析はガスクロマトグラフを用いて行い、N２、N２O、CO２、COなどを定量した。NOの還元除去率は生成したN２の収率から求めた。
(Adjustment of catalyst component and catalyst used in Examples)
(Preparation of catalyst components)
・ Preparation of alumina by sol-gel methodPrecipitation was generated by dropping 50 g of aluminum s-butoxide (Al (OC 4 H 9 ) 4 ) into 2000 ml of distilled water cooled with ice water, and using a stirring blade. The stirring was continued for 2 hours. The produced precipitate was separated from the supernatant by decantation, and the obtained precipitate was washed with distilled water. The obtained precipitate was dried in air at 110 ° C. for a whole day and night and then calcined in air at 400 ° C. for 5 hours. The obtained powder was ground and sieved, and one having a particle size of 50 μm or less was used.
-Preparation of alumina-supported silver catalyst [A] Silver was supported on alumina by an impregnation method. Add 5 g of the above alumina to an aqueous solution of 0.33 g of silver nitrate (AgNO 3 ) in 20 ml of distilled water, remove excess water while stirring on a hot plate kept at 80 ° C., and dry at 110 ° C. overnight. And calcining in air at 600 ° C. for 5 hours to obtain an alumina-supported silver catalyst [A]. At this time, the silver content relative to the catalyst was about 4 wt% in terms of silver metal (Ag).
-Preparation of alumina-supported silver catalyst [B] The alumina-supported silver catalyst [A] described above was used except that the alumina prepared by the sol-gel method was replaced with Mizusawa Chemical's alumina (trade name "GB-45", 190 m 2 / g). ] To prepare an alumina-supported silver catalyst [B].
・ Preparation of alumina-supported gallium catalyst Prepared in the same manner as the alumina-supported silver catalyst [A], except that 1.09 g of gallium nitrate (Ga (NO 3 ) 3 · xH 2 O) was used instead of silver nitrate. A gallium catalyst was obtained. At this time, the gallium content relative to the catalyst was about 4 wt% in terms of gallium metal (Ga).
・ Preparation of alumina supported tungsten catalyst Same as the above alumina supported silver catalyst [A] except that 0.30 g of ammonium paratungstate (5 (NH 4 ) 2 O · 13WO 3 · 5H 2 O) was used instead of silver nitrate. Thus, an alumina-supported tungsten catalyst was obtained. At this time, the content of tungsten with respect to the catalyst was about 4 wt% in terms of tungsten metal (W).
・ Preparation of alumina-supported indium catalyst Prepared in the same manner as the alumina-supported silver catalyst [A], except that 0.64 g of indium nitrate (In (NO 3 ) 3 · 3H 2 O) was used instead of silver nitrate. An indium catalyst was obtained. At this time, the content of indium with respect to the catalyst was about 4 wt% in terms of indium metal (In).
・ Preparation of alumina supported cobalt catalyst Prepared in the same manner as the above alumina supported silver catalyst [A] except that 1.03 g of cobalt nitrate (Co (NO 3 ) 2 · 6H 2 O) was used instead of silver nitrate. A cobalt catalyst was obtained. At this time, the content of cobalt with respect to the catalyst was about 4 wt% in terms of cobalt metal (Co).
・ Preparation of alumina-supported iron catalyst Prepared in the same manner as the above alumina-supported silver catalyst [A] except that 1.51 g of iron nitrate (Fe (NO 3 ) 3 · 9H 2 O) was used instead of silver nitrate. An iron catalyst was obtained. At this time, the iron content relative to the catalyst was about 4 wt% in terms of iron metal (Fe).
[Evaluation of catalyst activity]
0.04 g of the catalyst of the present invention obtained as described above was charged into an atmospheric pressure flow reactor, about 500 ppm nitric oxide (hereinafter referred to as “NO”), about 10 vol% oxygen, about 300 ppm. The reaction was performed by flowing a simulated helium-balanced exhaust gas containing n-decane and about 6 vol% H 2 O at a flow rate of 90 ml / min (corresponding to SV = 75000 h −1 ). The water was introduced as water vapor by adding water to the heating part of the reaction tube using a microplunger pump. The analysis of the reaction gas was performed using a gas chromatograph, and N 2 , N 2 O, CO 2 , CO and the like were quantified. Reducing the removal rate of NO was determined from the resulting N 2 yield.
上記の〔触媒構成成分の調製〕で調製したアルミナ担持銀触媒［Ａ］とアルミナを、それぞれ0.03g、0.01g計り取り、試薬瓶の中で振り混ぜて物理混合した。得られた本発明の触媒は、上記の〔触媒活性評価〕に従い、200〜600℃の温度範囲で活性の評価を行った。評価結果を表１に示す。 0.03 g and 0.01 g of the alumina-supported silver catalyst [A] and alumina prepared in the above [Preparation of catalyst component] were weighed out and shaken and mixed physically in a reagent bottle. The obtained catalyst of the present invention was evaluated for activity in the temperature range of 200 to 600 ° C. in accordance with the above [Evaluation of catalytic activity]. The evaluation results are shown in Table 1.
上記の〔触媒構成成分の調製〕で調製したアルミナ担持銀触媒［Ａ］とアルミナ担持ガリウム触媒を、それぞれ0.03g、0.01g計り取り、試薬瓶の中で振り混ぜて物理混合した。得られた本発明の触媒は、実施例１と同様にして活性評価を行い、評価結果を表１に示す。 0.03 g and 0.01 g of the alumina-supported silver catalyst [A] and the alumina-supported gallium catalyst prepared in the above [Preparation of catalyst constituents] were weighed out and shaken and mixed physically in a reagent bottle. The obtained catalyst of the present invention was evaluated for activity in the same manner as in Example 1, and the evaluation results are shown in Table 1.
上記の〔触媒構成成分の調製〕で調製したアルミナ担持銀触媒［Ａ］とアルミナ担持タングステン触媒を、それぞれ0.03g、0.01g計り取り、試薬瓶の中で振り混ぜて物理混合した。得られた本発明の触媒は、実施例１と同様にして活性評価を行い、評価結果を表１に示す。 0.03 g and 0.01 g of the alumina-supported silver catalyst [A] and the alumina-supported tungsten catalyst prepared in the above [Preparation of catalyst component] were weighed out and shaken and mixed physically in a reagent bottle. The obtained catalyst of the present invention was evaluated for activity in the same manner as in Example 1, and the evaluation results are shown in Table 1.
上記の〔触媒構成成分の調製〕で調製したアルミナ担持銀触媒［Ａ］とアルミナ担持インジウム触媒を、それぞれ0.03g、0.01g計り取り、試薬瓶の中で振り混ぜて物理混合した。得られた本発明の触媒は、実施例１と同様にして活性評価を行い、評価結果を表１に示す。 0.03 g and 0.01 g of the alumina-supported silver catalyst [A] and the alumina-supported indium catalyst prepared in the above-mentioned [Preparation of catalyst component] were weighed out and shaken and mixed physically in a reagent bottle. The obtained catalyst of the present invention was evaluated for activity in the same manner as in Example 1, and the evaluation results are shown in Table 1.
上記の〔触媒構成成分の調製〕で調製したアルミナ担持銀触媒［Ａ］とアルミナ担持コバルト触媒を、それぞれ0.03g、0.01g計り取り、試薬瓶の中で振り混ぜて物理混合した。得られた本発明の触媒は、実施例１と同様にして活性評価を行い、評価結果を表１に示す。 0.03 g and 0.01 g of the alumina-supported silver catalyst [A] and the alumina-supported cobalt catalyst prepared in the above-mentioned [Preparation of catalyst component] were weighed and shaken and mixed physically in a reagent bottle. The obtained catalyst of the present invention was evaluated for activity in the same manner as in Example 1, and the evaluation results are shown in Table 1.
上記の〔触媒構成成分の調製〕で調製したアルミナ担持銀触媒［Ａ］とアルミナ担持鉄触媒を、それぞれ0.03g、0.01g計り取り、試薬瓶の中で振り混ぜて物理混合した。得られた本発明の触媒は、実施例１と同様にして活性評価を行い、評価結果を表１に示す。 0.03 g and 0.01 g of the alumina-supported silver catalyst [A] and the alumina-supported iron catalyst prepared in the above-mentioned [Preparation of catalyst component] were weighed out and shaken and mixed physically in a reagent bottle. The obtained catalyst of the present invention was evaluated for activity in the same manner as in Example 1, and the evaluation results are shown in Table 1.
比較例１
上記の〔触媒構成成分の調製〕で調製したアルミナを0.04g使用して、実施例1と同様にして実施例１と同様にして活性評価を行い、評価結果を表１に示す。
Comparative Example 1
Using 0.04 g of the alumina prepared in the above [Preparation of catalyst component], activity evaluation was performed in the same manner as in Example 1 in the same manner as in Example 1, and the evaluation results are shown in Table 1.
比較例２
上記の〔触媒構成成分の調製〕で調製したアルミナ担持銀触媒［Ａ］を0.04g使用して、実施例1と同様にして実施例１と同様にして活性評価を行い、評価結果を表１に示す。
Comparative Example 2
Using 0.04 g of the alumina-supported silver catalyst [A] prepared in the above [Preparation of catalyst component], the activity was evaluated in the same manner as in Example 1 in the same manner as in Example 1, and the evaluation results are shown in Table 1. Shown in
比較例３
上記の〔触媒構成成分の調製〕で調製したアルミナ担持ガリウム触媒を0.04g使用して、実施例1と同様にして実施例１と同様にして活性評価を行い、評価結果を表１に示す。
Comparative Example 3
Using 0.04 g of the alumina-supported gallium catalyst prepared in the above [Preparation of catalyst component], the activity was evaluated in the same manner as in Example 1 in the same manner as in Example 1, and the evaluation results are shown in Table 1.
比較例４
上記の〔触媒構成成分の調製〕で調製したアルミナ担持タングステン触媒を0.04g使用して、実施例1と同様にして実施例１と同様にして活性評価を行い、評価結果を表１に示す。
Comparative Example 4
Using 0.04 g of the alumina-supported tungsten catalyst prepared in the above [Preparation of catalyst component], the activity was evaluated in the same manner as in Example 1 in the same manner as in Example 1, and the evaluation results are shown in Table 1.
比較例５
上記の〔触媒構成成分の調製〕で調製したアルミナ担持インジウム触媒を0.04g使用して、実施例1と同様にして実施例１と同様にして活性評価を行い、評価結果を表１に示す。
Comparative Example 5
Using 0.04 g of the alumina-supported indium catalyst prepared in the above [Preparation of catalyst component], the activity was evaluated in the same manner as in Example 1 in the same manner as in Example 1, and the evaluation results are shown in Table 1.
比較例６
上記の〔触媒構成成分の調製〕で調製したアルミナ担持コバルト触媒を0.04g使用して、実施例1と同様にして実施例１と同様にして活性評価を行い、評価結果を表１に示す。
Comparative Example 6
Using 0.04 g of the alumina-supported cobalt catalyst prepared in the above [Preparation of catalyst component], the activity was evaluated in the same manner as in Example 1 in the same manner as in Example 1, and the evaluation results are shown in Table 1.
比較例７
上記の〔触媒構成成分の調製〕で調製したアルミナ担持鉄触媒を0.04g使用して、実施例1と同様にして実施例１と同様にして活性評価を行い、評価結果を表１に示す。
Comparative Example 7
Using 0.04 g of the alumina-supported iron catalyst prepared in the above [Preparation of catalyst component], activity evaluation was performed in the same manner as in Example 1 in the same manner as in Example 1, and the evaluation results are shown in Table 1.
上記の〔触媒構成成分の調製〕で調製したアルミナ担持銀触媒［Ｂ］とアルミナ担持ガリウム触媒を、それぞれ0.03g、0.01g計り取り、試薬瓶の中で振り混ぜて物理混合した。得られた本発明の触媒は、実施例１と同様にして活性評価を行い、評価結果を表２に示す。 0.03 g and 0.01 g of the alumina-supported silver catalyst [B] and the alumina-supported gallium catalyst prepared in the above-mentioned [Preparation of catalyst component] were weighed out and shaken and mixed physically in a reagent bottle. The obtained catalyst of the present invention was evaluated for activity in the same manner as in Example 1, and the evaluation results are shown in Table 2.
比較例８
上記の〔触媒構成成分の調製〕で調製したアルミナ担持銀触媒［Ｂ］を0.04g使用して、実施例1と同様にして実施例１と同様にして活性評価を行い、評価結果を表２に示す。
Comparative Example 8
Using 0.04 g of the alumina-supported silver catalyst [B] prepared in the above [Preparation of catalyst component], the activity was evaluated in the same manner as in Example 1 in the same manner as in Example 1, and the evaluation results are shown in Table 2. Shown in
上記の〔触媒構成成分の調製〕で調製したアルミナ担持銀触媒［Ａ］とアルミナ担持ガリウム触媒を、それぞれ0.02g、0.02g計り取り、試薬瓶の中で振り混ぜて物理混合した。得られた本発明の触媒は、実施例１と同様にして活性評価を行い、評価結果を表３に示す。 0.02 g and 0.02 g of the alumina-supported silver catalyst [A] and the alumina-supported gallium catalyst prepared in the above-mentioned [Preparation of catalyst component] were weighed out and shaken and mixed physically in a reagent bottle. The obtained catalyst of the present invention was evaluated for activity in the same manner as in Example 1, and the evaluation results are shown in Table 3.
上記の〔触媒構成成分の調製〕で調製したアルミナ担持銀触媒［Ａ］とアルミナ担持ガリウム触媒を、それぞれ0.01g、0.03g計り取り、試薬瓶の中で振り混ぜて物理混合した。得られた本発明の触媒は、実施例１と同様にして活性評価を行い、評価結果を表３に示す。
0.01 g and 0.03 g of the alumina-supported silver catalyst [A] and the alumina-supported gallium catalyst prepared in the above [Preparation of catalyst constituents] were weighed out and shaken and mixed physically in a reagent bottle. The obtained catalyst of the present invention was evaluated for activity in the same manner as in Example 1, and the evaluation results are shown in Table 3.
実施例１の物理混合触媒を用い、上記の〔触媒活性評価〕において、1ppmの硫黄酸化物(SO2)を導入し、また還元剤としてNOに対する重量比で約5倍量の軽油を用いた以外は、実施例１と同様にして活性評価を行い、評価結果を表４に示す。 Using the physical mixed catalyst of Example 1, in the above [Evaluation of catalytic activity], 1 ppm of sulfur oxide (SO 2 ) was introduced, and about 5 times as much light oil as NO. Except for the above, activity evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Table 4.
比較例９
比較例２の触媒を用い、1ppmの硫黄酸化物(SO2)を導入し、また還元剤としてNOに対する重量比で約5倍量の軽油を用いた以外は実施例1と同様にしてNOの還元反応を行い、その結果を比較例９として表４に示した。
Comparative Example 9
The catalyst of Comparative Example 2 was used, 1 ppm of sulfur oxide (SO 2 ) was introduced, and about 5 times the amount of diesel oil in a weight ratio to NO was used as the reducing agent. The reduction reaction was performed, and the result is shown in Table 4 as Comparative Example 9.
比較例１０
比較例３の触媒を用い、1ppmの硫黄酸化物(SO2)を導入し、また還元剤としてNOに対する重量比で約5倍量の軽油を用いた以外は実施例1と同様にしてNOの還元反応を行い、その結果を比較例１０として表４に示した。
Comparative Example 10
Using the catalyst of Comparative Example 3, 1 ppm of sulfur oxide (SO 2 ) was introduced, and about 5 times the amount of diesel oil in a weight ratio with respect to NO was used as the reducing agent. A reduction reaction was performed, and the result is shown in Table 4 as Comparative Example 10.
本発明の触媒は、ディーゼル機関やリーンバーンガソリンエンジンをはじめ、種々の内燃機関や燃焼器より排出される排ガス中に含まれる窒素酸化物を効率よく除去することができるので、産業上の利用可能性が極めて高いものである。
The catalyst of the present invention can be used industrially because it can efficiently remove nitrogen oxides contained in exhaust gas discharged from various internal combustion engines and combustors including diesel engines and lean burn gasoline engines. The property is extremely high.
Claims (4)
The oxidizing atmosphere in which water vapor and excess oxygen are present is exhaust gas from a diesel engine, the reducing agent is light oil, and the nitrogen oxide is nitrogen oxide from a diesel engine. A catalyst for selectively reducing and removing nitrogen oxides described in one.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013059721A (en) * | 2011-09-13 | 2013-04-04 | National Institute Of Advanced Industrial Science & Technology | Exhaust gas clarifying catalyst, usage of exhaust gas clarifying catalyst and method for producing exhaust gas clarifying catalyst |
| JPWO2018047964A1 (en) * | 2016-09-12 | 2019-08-15 | 株式会社キャタラー | Exhaust gas purification catalyst and method for producing exhaust gas purification catalyst |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06154607A (en) * | 1992-11-20 | 1994-06-03 | Riken Corp | Catalyst for removal of nitrogen oxide and method for removing nitrogen oxide |
| JPH08323202A (en) * | 1995-06-01 | 1996-12-10 | Riken Corp | Exhaust gas purifying material and exhaust gas purifying method |
| JPH0957064A (en) * | 1995-08-21 | 1997-03-04 | Riken Corp | Waste gas purifying material and waste gas purifying method |
| JPH09122493A (en) * | 1995-10-27 | 1997-05-13 | Sangyo Souzou Kenkyusho | Catalyst and process for removing nitrogen oxide in engine exhaust gas |
| JP2000153133A (en) * | 1998-11-18 | 2000-06-06 | Sumitomo Metal Mining Co Ltd | Exhaust gas purification |
-
2005
- 2005-09-16 JP JP2005269300A patent/JP2007075774A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06154607A (en) * | 1992-11-20 | 1994-06-03 | Riken Corp | Catalyst for removal of nitrogen oxide and method for removing nitrogen oxide |
| JPH08323202A (en) * | 1995-06-01 | 1996-12-10 | Riken Corp | Exhaust gas purifying material and exhaust gas purifying method |
| JPH0957064A (en) * | 1995-08-21 | 1997-03-04 | Riken Corp | Waste gas purifying material and waste gas purifying method |
| JPH09122493A (en) * | 1995-10-27 | 1997-05-13 | Sangyo Souzou Kenkyusho | Catalyst and process for removing nitrogen oxide in engine exhaust gas |
| JP2000153133A (en) * | 1998-11-18 | 2000-06-06 | Sumitomo Metal Mining Co Ltd | Exhaust gas purification |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013059721A (en) * | 2011-09-13 | 2013-04-04 | National Institute Of Advanced Industrial Science & Technology | Exhaust gas clarifying catalyst, usage of exhaust gas clarifying catalyst and method for producing exhaust gas clarifying catalyst |
| JPWO2018047964A1 (en) * | 2016-09-12 | 2019-08-15 | 株式会社キャタラー | Exhaust gas purification catalyst and method for producing exhaust gas purification catalyst |
| US11311859B2 (en) * | 2016-09-12 | 2022-04-26 | Cataler Corporation | Exhaust gas purification catalyst and method for manufacturing exhaust gas purification catalyst |
| JP7105190B2 (en) | 2016-09-12 | 2022-07-22 | 株式会社キャタラー | Exhaust gas purifying catalyst and method for producing exhaust gas purifying catalyst |
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