JP3155140B2 - Denitration catalyst and denitration method - Google Patents
Denitration catalyst and denitration methodInfo
- Publication number
- JP3155140B2 JP3155140B2 JP34430293A JP34430293A JP3155140B2 JP 3155140 B2 JP3155140 B2 JP 3155140B2 JP 34430293 A JP34430293 A JP 34430293A JP 34430293 A JP34430293 A JP 34430293A JP 3155140 B2 JP3155140 B2 JP 3155140B2
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- denitration
- alumina
- containing layer
- exhaust gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000003054 catalyst Substances 0.000 title claims description 155
- 238000000034 method Methods 0.000 title claims description 45
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 80
- 239000007789 gas Substances 0.000 claims description 74
- 239000000758 substrate Substances 0.000 claims description 25
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 18
- 229910052709 silver Inorganic materials 0.000 claims description 18
- 239000004332 silver Substances 0.000 claims description 18
- 238000002485 combustion reaction Methods 0.000 claims description 13
- 238000012856 packing Methods 0.000 claims description 13
- 239000011248 coating agent Substances 0.000 claims description 11
- 238000000576 coating method Methods 0.000 claims description 11
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 10
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 claims description 9
- 229910052753 mercury Inorganic materials 0.000 claims description 9
- 239000000446 fuel Substances 0.000 claims description 7
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 238000001179 sorption measurement Methods 0.000 claims description 5
- 239000011819 refractory material Substances 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 3
- 230000035515 penetration Effects 0.000 claims description 2
- 241000264877 Hippospongia communis Species 0.000 description 40
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 28
- 229930195733 hydrocarbon Natural products 0.000 description 21
- 150000002430 hydrocarbons Chemical class 0.000 description 21
- 238000011156 evaluation Methods 0.000 description 18
- 238000006722 reduction reaction Methods 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- 238000006243 chemical reaction Methods 0.000 description 10
- 239000012298 atmosphere Substances 0.000 description 6
- 239000003638 chemical reducing agent Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 5
- 239000011230 binding agent Substances 0.000 description 5
- 229910002091 carbon monoxide Inorganic materials 0.000 description 5
- 230000018044 dehydration Effects 0.000 description 5
- 238000006297 dehydration reaction Methods 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- 239000008367 deionised water Substances 0.000 description 4
- 229910021641 deionized water Inorganic materials 0.000 description 4
- 238000006073 displacement reaction Methods 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 238000003878 thermal aging Methods 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- LFYJSSARVMHQJB-QIXNEVBVSA-N bakuchiol Chemical compound CC(C)=CCC[C@@](C)(C=C)\C=C\C1=CC=C(O)C=C1 LFYJSSARVMHQJB-QIXNEVBVSA-N 0.000 description 3
- 229910052878 cordierite Inorganic materials 0.000 description 3
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- 238000002459 porosimetry Methods 0.000 description 3
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 3
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910001961 silver nitrate Inorganic materials 0.000 description 2
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- 229910000873 Beta-alumina solid electrolyte Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- VXAUWWUXCIMFIM-UHFFFAOYSA-M aluminum;oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Al+3] VXAUWWUXCIMFIM-UHFFFAOYSA-M 0.000 description 1
- -1 and simultaneously Chemical class 0.000 description 1
- 229910001593 boehmite Inorganic materials 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000007809 chemical reaction catalyst Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910001923 silver oxide Inorganic materials 0.000 description 1
- GGCZERPQGJTIQP-UHFFFAOYSA-N sodium;9,10-dioxoanthracene-2-sulfonic acid Chemical compound [Na+].C1=CC=C2C(=O)C3=CC(S(=O)(=O)O)=CC=C3C(=O)C2=C1 GGCZERPQGJTIQP-UHFFFAOYSA-N 0.000 description 1
- 238000003980 solgel method Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000000844 transformation Methods 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Description
【０００１】[0001]
【産業上の利用分野】本発明は、排気ガス、特に自動車
などの内燃機関の排気ガス中の窒素酸化物の除去に用い
られる排気ガス浄化に好適な触媒およびそれを用いる脱
硝方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst suitable for purifying exhaust gas used for removing nitrogen oxides from exhaust gas, particularly exhaust gas of an internal combustion engine such as an automobile, and a denitration method using the same.
【０００２】[0002]
【従来の技術】地球温暖化防止の観点から、近年二酸化
炭素の排出を抑制することができる希薄燃焼方式の内燃
機関、例えばリーンバーンガソリンエンジン、ディーゼ
ルエンジン等が注目されている。この種の内燃機関の排
気ガスは、一酸化炭素（ＣＯ）や炭化水素（ＨＣ）、水
素（Ｈ2 ）といった還元性成分と窒素酸化物（ＮＯ
ｘ）、酸素（Ｏ2 ）といった酸化性成分とを合わせ含む
が、量的には酸素過剰であり、かつ燃焼生成物の水蒸気
をも含有しているという特徴がある。2. Description of the Related Art In recent years, from the viewpoint of preventing global warming, a lean burn type internal combustion engine capable of suppressing carbon dioxide emission, such as a lean burn gasoline engine and a diesel engine, has been receiving attention. The exhaust gas of this type of internal combustion engine includes reducing components such as carbon monoxide (CO), hydrocarbons (HC), and hydrogen (H 2 ) and nitrogen oxides (NO).
x) and oxidizing components such as oxygen (O 2 ), but are characterized in that they are excessive in oxygen and also contain water vapor as a combustion product.
【０００３】従来、この種の排気ガスを浄化するために
触媒として、例えばアルミナやアルミナに遷移金属を担
持した触媒が、炭化水素を還元剤として用いるＮＯｘ還
元反応に有効であるとする数多くの報告がある。特開平
４−９０８２６号公報の実施例には、ＦＣＣ用粉状アル
ミナをＮＯｘ還元触媒として使用した例が報告されてい
る。また、特開平４−２８４８４８号公報には０．１〜
４重量％のＣｕ，Ｆｅ，Ｃｒ，Ｚｎ，Ｎｉ，Ｖを含有す
るアルミナあるいはシリカ−アルミナをＮＯｘ還元触媒
として使用した例が報告されている。更に、Ｐｔをアル
ミナに担持した触媒を用いると、ＮＯｘ還元反応が２０
０〜３００℃程度の低温領域で進行することが特開平４
−２６７９４６号公報、特開平５−６８８５５公報や特
開平５−１０３９４９号公報等に報告されている。しか
しながら、これらの担持貴金属触媒を用いた場合、還元
剤である炭化水素の燃焼反応が促進されＮＯｘ還元反応
の選択性が乏しいといった欠点を有していた。Heretofore, there have been many reports that a catalyst for purifying this kind of exhaust gas, for example, alumina or a catalyst having a transition metal supported on alumina is effective for a NOx reduction reaction using hydrocarbon as a reducing agent. There is. Japanese Patent Application Laid-Open No. 4-90826 discloses an example in which powdery alumina for FCC is used as a NOx reduction catalyst. In addition, Japanese Patent Application Laid-Open No.
An example in which alumina or silica-alumina containing 4% by weight of Cu, Fe, Cr, Zn, Ni and V is used as a NOx reduction catalyst has been reported. Further, when a catalyst in which Pt is supported on alumina is used, NOx reduction
The process proceeds in a low temperature range of about 0 to 300 ° C.
-267946, JP-A-5-68855 and JP-A-5-103949. However, when these supported noble metal catalysts are used, there is a disadvantage that the combustion reaction of hydrocarbons as a reducing agent is promoted and the selectivity of the NOx reduction reaction is poor.
【０００４】本出願人の一方は先に、酸素過剰雰囲気下
で炭化水素を還元剤として銀を含有する触媒を用いると
ＮＯｘ還元反応が選択的に進行することを見い出し、特
開平４−２８１８４４号公報に開示した。この開示の
後、銀を含有する触媒を用いる類似のＮＯｘ還元技術が
特開平４−３５４５３６号公報や特開平５−９２１２４
号公報あるいは特開平５−９２１２５号に開示されるに
至った。また、AppliedCatalysis B:Environmental,2(1
993)199-205には、銀を担持したアルミナ触媒がＣｏ，
Ｃｕ，Ｖ，Ｃｒを担持したアルミナ触媒よりも、水蒸気
共存下でのＮＯｘ還元性能において優れていることが報
告されている。しかしながら、これらの従来の銀担持ア
ルミナ触媒は水蒸気共存下での、炭化水素によるＮＯX
還元反応触媒としては活性がまだ不十分であった。One of the present applicants has previously found that the use of a catalyst containing silver as a reducing agent with hydrocarbons in an oxygen-excess atmosphere causes the NOx reduction reaction to proceed selectively. Published in the gazette. After this disclosure, similar NOx reduction techniques using a catalyst containing silver have been disclosed in Japanese Patent Application Laid-Open Nos. 4-354536 and 5-92124.
Or JP-A-5-92125. AppliedCatalysis B: Environmental, 2 (1
993) 199-205 discloses that an alumina catalyst supporting silver is Co,
It is reported that the catalyst is superior in NOx reduction performance in the presence of water vapor to an alumina catalyst supporting Cu, V, and Cr. However, these conventional silver-supported alumina catalyst under steam coexistence, according hydrocarbons NO X
The activity was still insufficient as a reduction reaction catalyst.
【０００５】更に、従来よりアルミナを担体として用い
る触媒は空間速度依存性が大きいことが知られている。
すなわちＳＶ：１０００〜１００００／ｈ程度の低空間
速度では十分なＮＯｘ還元性能を発揮するが、ＳＶ：１
００００／ｈ以上の高空間速度では特に水分共存下では
ＮＯｘ除去性能が大きく低下するとの多数の報告があ
り、斯界の常識でもあった。例えば、特開平５−９２１
２４に開示されている排気ガス処理方法が、排気ガスと
触媒との接触時間を０．０３ｇ．ｓｅｃ／ｃｍ3以上、
更に好ましくは０．１ｇ．ｓｅｃ／ｃｍ3 以上と限定し
ているのはこの為である。しかしながら、希薄空燃比で
運転される内燃機関の代表的なものである自動車等の車
両用のリーンバーンエンジンの排気ガス処理において
は、実用上欠くことのできない今一つの性能は、触媒層
ないしは触媒で被覆した支持基質からなる構造体（以
下、これらを本明細書では触媒含有層という）の所要ス
ぺース及び重量である。エンジンの排気量と仕事量とを
勘案するとエンジン排気量の数倍以上の容量の触媒含有
層を積載することは実用的ではないからである。したが
って、通常、触媒含有層の容量はエンジン排気量以下で
あることが好ましい。このことは、実用性のある触媒含
有層を構成するには、触媒と排気ガスとの接触時間が非
常に短いこと、すなわち0.03ｇ．ｓｅｃ／ｃｍ3 未満、
好ましくは0.02ｇ．ｓｅｃ／ｃｍ3 以下であることが求
められることを意味する（実用的なガス空間速度は７，
０００／ｈｒを超え、好ましくは１０，０００／ｈｒ以
上だからである）。しかしながら、従来の銀担持アルミ
ナ触媒は、このような短い接触時間では水蒸気共存排気
ガスに対する脱硝性能が不十分であった。Further, it has been known that a catalyst using alumina as a carrier has a large space velocity dependency.
In other words, SV: exhibits a sufficient NOx reduction performance at a low space velocity of about 1000 to 10000 / h.
There have been many reports that NOx removal performance is greatly reduced at high space velocities of 0000 / h or more, especially in the presence of moisture, and was also common knowledge in the art. For example, Japanese Patent Application Laid-Open No. 5-921
24, the contact time between the exhaust gas and the catalyst is 0.03 g. sec / cm 3 or more,
More preferably, 0.1 g. This is why it is limited to sec / cm 3 or more. However, in exhaust gas treatment of a lean burn engine for a vehicle such as an automobile, which is a typical example of an internal combustion engine operated at a lean air-fuel ratio, another performance that is indispensable for practical use is a catalyst layer or a catalyst. The required space and weight of the structure comprising the coated supporting substrate (hereinafter referred to as the catalyst-containing layer in the present specification). This is because it is not practical to load a catalyst-containing layer having a capacity several times or more the engine displacement in consideration of the engine displacement and the work load. Therefore, usually, the capacity of the catalyst-containing layer is preferably equal to or less than the engine displacement. This means that the contact time between the catalyst and the exhaust gas is very short, that is, 0.03 g. less than sec / cm 3 ,
Preferably 0.02 g. sec / cm 3 or less (the practical gas space velocity is 7,
000 / hr, preferably 10,000 / hr or more). However, the conventional silver-carrying alumina catalyst was insufficient in denitration performance against exhaust gas coexisting with steam at such a short contact time.
【０００６】[0006]
【発明の解決しようとする課題】そこで、本発明は、上
記従来技術の欠点を解消し、希薄空燃比で運転される内
燃機関の排気ガス中のＮＯｘを充分短い接触時間（充分
高いガス空間速度）で効率よく除去でき、かつ充分な高
温耐熱性を有する触媒および該触媒を使用する高効率、
高信頼性の脱硝方法を提供することにある。SUMMARY OF THE INVENTION Accordingly, the present invention solves the above-mentioned disadvantages of the prior art and reduces the NOx in the exhaust gas of an internal combustion engine operated at a lean air-fuel ratio for a sufficiently short contact time (a sufficiently high gas space velocity). ), And a catalyst having sufficient high-temperature heat resistance and high efficiency using the catalyst;
An object of the present invention is to provide a highly reliable denitration method.
【０００７】[0007]
【課題を解決するための手段】本発明者らは、水蒸気が
共存する酸素過剰雰囲気下でも炭化水素によるＮＯｘ還
元反応が高効率的に進行する触媒及び脱硝方法について
鋭意研究を重ねた結果、特定の物性を有するアルミナに
銀を担持した触媒を用いることにより上記の課題を解決
することが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、窒素吸着法により測定された比表面積が
１２０ｍ2 ／ｇ以上で、水銀圧入法により測定された充
填密度が０．６０ｇ／ｃｍ3 以上で、かつ水銀圧入法に
より測定された真密度が１．８０ｇ／ｃｍ3 以下である
活性アルミナと、該活性アルミナに担持された銀とから
なる脱硝触媒を提供する。Means for Solving the Problems The present inventors have conducted intensive studies on a catalyst and a denitration method in which a NOx reduction reaction by hydrocarbon proceeds efficiently even in an oxygen-excess atmosphere in which water vapor coexists. It has been found that the above problem can be solved by using a catalyst in which silver is supported on alumina having the above physical properties, and the present invention has been completed. That is, the specific surface area measured by the nitrogen adsorption method is 120 m 2 / g or more, the packing density measured by the mercury intrusion method is 0.60 g / cm 3 or more, and the true density measured by the mercury intrusion method is 1 Provided is a denitration catalyst comprising activated alumina having a weight of 0.80 g / cm 3 or less and silver supported on the activated alumina.
【０００８】また、本発明は、多数の貫通孔を有し耐火
性材料からなる支持基質と、該支持基質の少なくとも前
記貫通孔の内表面上に被覆された上記の脱硝触媒とから
なり、前記貫通孔はその貫通の方向に垂直な断面で見た
ときに開孔率が６０〜９０％であり、貫通孔の数は5.06
ｃｍ 2 当り３０〜７００個であり、かつ該脱硝触媒の被
覆量が前記支持基質単位体積当り２０〜２００ｇ／Ｌで
ある脱硝触媒被覆構造体を提供する。Further, the present invention is composed of a supporting substrate made of a refractory material having a large number of through-holes, and the support substrate of at least the through hole above the denitration catalyst coated on the inner surface of the Through-hole viewed in cross section perpendicular to the direction of its penetration
Sometimes the porosity is 60-90% and the number of through holes is 5.06
The present invention provides a denitration catalyst-coated structure having 30 to 700 particles per cm 2 and a coating amount of the denitration catalyst of 20 to 200 g / L per unit volume of the support substrate.
【０００９】さらに、本発明は、希薄空燃比で運転され
る内燃機関の排気ガスを脱硝触媒含有層と接触させるこ
とからなる排気ガスの脱硝方法において、該脱硝触媒含
有層に含まれる脱硝触媒が上記の本発明により提供され
る脱硝触媒であり、かつ排気ガスが前記の脱硝触媒含有
層の入口において４５０〜６００℃であることを特徴と
する脱硝方法を提供する。Further, the present invention provides a method for denitration of exhaust gas, which comprises contacting exhaust gas of an internal combustion engine operated at a lean air-fuel ratio with a denitration catalyst-containing layer. A denitration method provided by the above denitration catalyst provided by the present invention, wherein exhaust gas is at 450 to 600 ° C. at an inlet of the denitration catalyst-containing layer.
【００１０】この脱硝方法に用いられる脱硝触媒含有層
は上記の触媒のみで構成されていてもよいし、上記の脱
硝触媒被覆構造体で構成されていてもよい。本発明の上
記方法によれば、排気ガスを触媒含有層と、触媒換算で
０．０２ｇ．ｓｅｃ／ｃｍ3 以下の時間で接触させても
十分に排気ガスの浄化が可能である。[0010] The denitration catalyst-containing layer used in this denitration method may be composed of only the above-mentioned catalyst or may be composed of the above-mentioned denitration catalyst-coated structure. According to the method of the present invention, the exhaust gas is mixed with the catalyst-containing layer in an amount of 0.02 g. The exhaust gas can be sufficiently purified even if the contact is performed for a time of not more than sec / cm 3 .
【００１１】本発明の脱硝触媒および脱硝方法によれ
ば、水蒸気が共存する酸素過剰雰囲気下でも効果的に排
気ガス中のＮＯｘを除去することができる。なお、本明
細書においては、触媒とガスとの接触時間は、ガス１ｃ
ｍ3 （標準状態換算）当りの触媒１ｇと接触する時間
（単位：ｇ．ｓｅｃ／ｃｍ3 ）で表す。また、排気ガス
の空間速度とは、触媒含有層の単位体積（１ｃｍ3 ）を
通過する排気ガスの体積流量（ｃｍ3 ／hr／ｃｍ3 ＝hr
-1）を意味する。なお、以下の説明においては、排気ガ
スの触媒含有層入口における温度を「触媒含有層入口ガ
ス温度」と称する。以下、本発明を更に詳細に説明す
る。According to the denitration catalyst and the denitration method of the present invention, NOx in the exhaust gas can be effectively removed even in an oxygen-excess atmosphere where water vapor coexists. In the present specification, the contact time between the catalyst and the gas is gas 1c
The time (unit: g.sec / cm 3 ) in contact with 1 g of catalyst per m 3 (converted to standard state). The space velocity of the exhaust gas refers to the volume flow rate (cm 3 / hr / cm 3 = hr) of the exhaust gas passing through the unit volume (1 cm 3 ) of the catalyst-containing layer.
-1 ). In the following description, the temperature of the exhaust gas at the inlet of the catalyst-containing layer is referred to as “catalyst-containing inlet gas temperature”. Hereinafter, the present invention will be described in more detail.
【００１２】〔触媒〕本発明の脱硝触媒は、窒素吸着法
により測定された比表面積１２０ｍ2 ／ｇ以上であり、
水銀圧入法により測定された充填密度０．６０ｇ／ｃｍ
3 以上であり、かつ真密度１．８０ｇ／ｃｍ3 以下であ
る活性アルミナを主成分とする。アルミナは、水酸化ア
ルミニウムが脱水されてα−アルミナになる間に多くの
変態をとるが、本発明で用いる活性アルミナは結晶学的
にはγ−，η−型あるいはその混合型に分類されるもの
である。[Catalyst] The denitration catalyst of the present invention has a specific surface area of at least 120 m 2 / g measured by a nitrogen adsorption method,
0.60 g / cm packing density measured by mercury intrusion method
The main component is activated alumina having a true density of not less than 3 and a true density of not more than 1.80 g / cm 3 . Alumina undergoes many transformations during the dehydration of aluminum hydroxide to α-alumina, but the activated alumina used in the present invention is crystallographically classified into γ-, η-type or a mixed type thereof. Things.
【００１３】他の結晶構造をとるアルミナ、例えばα−
アルミナは極端に比表面積が小さく固体酸性にも乏しい
ので、本発明の触媒担体としては不適当である。また、
δ−アルミナも比表面積が１００ｍ2 ／ｇ以下と小さす
ぎ、不十分である。その他のβ−アルミナやχ−アルミ
ナも本発明の脱硝触媒担体としては不適当である。用い
られる活性アルミナは、窒素吸着法により測定される比
表面積が１２０ｍ2 ／ｇ以上である。比表面積が１２０
ｍ2 ／ｇ未満であると、得られる銀担持触媒は、ＨＣの
転化活性が低くかつＮＯｘ転化活性も不十分である。Alumina having another crystal structure, for example, α-
Since alumina has an extremely small specific surface area and poor solid acidity, it is not suitable as the catalyst carrier of the present invention. Also,
δ-alumina also has a specific surface area of 100 m 2 / g or less, which is too small and insufficient. Other β-alumina and χ-alumina are also unsuitable as the denitration catalyst carrier of the present invention. The activated alumina used has a specific surface area of at least 120 m 2 / g as measured by a nitrogen adsorption method. Specific surface area is 120
When it is less than m 2 / g, the resulting silver-supported catalyst has low HC conversion activity and insufficient NOx conversion activity.
【００１４】また、活性アルミナは、水銀圧入法により
測定される充填密度が0.60ｇ／ｃｍ3 以上、好ましくは
0.65〜0.80g/ｃｍ3 である。該充填密度が0.60ｇ／ｃｍ
3 未満では、活性アルミナが嵩高く、得られる銀担持触
媒は、排気ガスに水分が含まれていると脱硝性能が低
い。特に、触媒とガスとの接触時間が０．０２ｇ．ｓｅ
ｃ／ｃｍ3 以下の短かい接触時間（高空間速度）の条件
では、ＮＯｘ転化率が著しく低下する。The activated alumina has a packing density of at least 0.60 g / cm 3 , measured by a mercury intrusion method, preferably
0.65 to 0.80 g / cm 3 . The packing density is 0.60 g / cm
If it is less than 3 , the activated alumina is bulky, and the resulting silver-supported catalyst has low denitration performance when the exhaust gas contains moisture. In particular, the contact time between the catalyst and the gas is 0.02 g. se
Under conditions of short contact time (high space velocity) of c / cm 3 or less, the NOx conversion is significantly reduced.
【００１５】さらに、活性アルミナは、水銀圧入法によ
り測定される真密度が1.80ｇ／ｃｍ3 以下であり、好ま
しく1.30〜1.65ｇ／ｃｍ3 である。該真密度が１．８０
を越えると、得られる銀担持アルミナ触媒は水分共存下
でのＮＯｘ転化活性の低いものとなる。Furthermore, activated alumina, a true density measured by mercury porosimetry is at 1.80 g / cm 3 or less, preferably 1.30~1.65g / cm 3. The true density is 1.80
Is exceeded, the obtained silver-supported alumina catalyst has a low NOx conversion activity in the presence of moisture.
【００１６】該活性アルミナは、鉱物学上シブサイト、
ベーマイト、擬ベーマイト、バイアライト、あるいはノ
ルストランダイトに分類される水酸化アルミニウムの粉
体やゲルを、空気中あるいは真空中で３００〜８００
℃、好ましくは４００〜６００℃で加熱して脱水するこ
とによって調製される。一般に、活性アルミナは前駆体
である水酸化アルミニウムの脱水過程で、脱水方法、脱
水時間及び／又は脱水雰囲気等に依存して、結晶化度、
結晶形態、粒子サイズ及び／またはミクロ、メソ、マク
ロの細孔構造等に違いができる。このため、比表面積、
充填密度及び真密度等の物性の異なる活性アルミナがで
きるが、上記の条件を満たすものを選択する必要があ
る。The activated alumina may be minebologically sibbsite,
Powder or gel of aluminum hydroxide classified as boehmite, pseudo-boehmite, vialite, or norstrandite is placed in air or vacuum for 300-800.
It is prepared by heating at 400C, preferably 400-600C for dehydration. In general, activated alumina is used in the course of dehydrating aluminum hydroxide as a precursor, depending on the dehydration method, the dehydration time and / or the dehydration atmosphere, and the like.
Differences can be made in crystal morphology, particle size and / or micro, meso, macro pore structure, and the like. For this reason, the specific surface area,
Activated alumina having different physical properties such as packing density and true density can be produced, but it is necessary to select one that satisfies the above conditions.
【００１７】本発明のアルミナ触媒は銀を担持するもの
である。担持される銀の形態は特に限定されないが、通
常金属状の銀及び／又は酸化銀である。該触媒における
銀の担持率は特に限定されないが、活性アルミナに対し
て金属銀換算で１〜６重量％の範囲が好ましい。銀の担
持率が低すぎると、水蒸気共存下での脱硝触媒活性が極
端に低くなる。高すぎると、還元剤として作用する炭化
水素の燃焼反応が過度に促進され、脱硝反応の活性及び
選択性が低下する。The alumina catalyst of the present invention supports silver. The form of the supported silver is not particularly limited, but is usually metallic silver and / or silver oxide. The loading ratio of silver in the catalyst is not particularly limited, but is preferably in the range of 1 to 6% by weight in terms of metallic silver based on activated alumina. If the silver loading is too low, the denitration catalytic activity in the presence of steam becomes extremely low. If it is too high, the combustion reaction of the hydrocarbon acting as a reducing agent is excessively promoted, and the activity and selectivity of the denitration reaction decrease.
【００１８】銀の担持方法は特に限定されない。例えば
水溶性の銀塩を用い、インシピエントウェットネス法や
蒸発乾固法などを含む通常の含浸法で銀をアルミナ担体
上に付着させた後、乾燥、焼成処理することによって担
持される。乾燥温度は特に限定するものではなく、通常
８０〜１２０℃程度で乾燥した後、３００〜８００℃、
好ましくは４００〜６００℃程度で焼成する方法が行わ
れる。焼成温度が８００℃を越えると、アルミナの相変
態が起こるので好ましくない。The method for supporting silver is not particularly limited. For example, using a water-soluble silver salt, silver is deposited on an alumina carrier by a usual impregnation method including an incipient wetness method and an evaporation to dryness method, and then dried and calcined to be supported. The drying temperature is not particularly limited, and usually after drying at about 80 to 120 ° C, 300 to 800 ° C,
Preferably, a method of firing at about 400 to 600 ° C. is performed. If the firing temperature exceeds 800 ° C., phase transformation of alumina occurs, which is not preferable.
【００１９】〔触媒含有層〕本発明の触媒を前述の脱硝
方法に使用する際の触媒含有層の形態は特に制限されな
い。例えば、該脱硝方法に用いられる触媒含有層を該触
媒のみで構成してもよい。この場合には、通常、一定空
間内に触媒を充填する方法、所要の一定形状に触媒を成
形する方法などが考えられる。成形触媒の形状は特に制
限されず、例えば球状、円筒状、ハニカム状、ラセン
状、粒状などが挙げられる。形状、大きさなどは使用条
件に応じて任意に選択することができる。[Catalyst-containing layer] The form of the catalyst-containing layer when the catalyst of the present invention is used in the aforementioned denitration method is not particularly limited. For example, the catalyst-containing layer used in the denitration method may be composed only of the catalyst. In this case, a method of filling the catalyst into a certain space, a method of molding the catalyst into a required certain shape, and the like are usually considered. The shape of the molded catalyst is not particularly limited, and examples thereof include a spherical shape, a cylindrical shape, a honeycomb shape, a spiral shape, and a granular shape. The shape, size, and the like can be arbitrarily selected according to use conditions.
【００２０】あるいは、触媒含有層は、触媒を支持基質
表面に被覆した構造体で構成してもよい。特に、自動車
のエンジンの排気ガス浄化の場合、エンジン排気量に比
較して不釣り合いに大きな容積の触媒含有層を排気系に
置くことは実用的でない。また、排気ガスの流れの中に
触媒含有層を置くことによる圧力損失を最小限に抑え、
長時間の実車走行使用においても振動等による摩耗を防
ぐ必要がある。このような場合には、触媒含有層を、排
気ガスの流れの方向に配置される多数の貫通孔を有し耐
火性材料からなる支持基質と、該支持基質の少なくとも
前記貫通孔の内表面上に被覆された上述の脱硝触媒とか
らなる脱硝触媒被覆構造体で構成することが好ましい。Alternatively, the catalyst-containing layer may be constituted by a structure in which a catalyst is coated on the surface of a supporting substrate. In particular, in the case of exhaust gas purification of an automobile engine, it is not practical to place a catalyst-containing layer having a disproportionately large volume in the exhaust system as compared with the engine displacement. In addition, minimizing pressure loss due to placing the catalyst containing layer in the exhaust gas flow,
It is necessary to prevent wear due to vibration and the like even when the vehicle is used for a long period of time. In such a case, the catalyst-containing layer is provided with a support substrate made of a refractory material having a large number of through holes arranged in the direction of the flow of the exhaust gas, and at least an inner surface of the through hole of the support substrate. It is preferable to constitute a denitration catalyst coating structure composed of the above-mentioned denitration catalyst coated on the substrate.
【００２１】支持基質の耐火性材料としてはα−アルミ
ナ、ムライト、コージェライト、シリコンカーバイド等
のセラミックスやオーステナイト系やフェライト系のス
テンレス鋼等の金属等が使用される。形状もハニカムや
フォーム等の慣用のものが使用できる。好ましいもの
は、コージェライト製、ステンレス鋼製のもので、ハニ
カム状の支持基質である。支持基質には多数の貫通孔が
排気ガスの流れ方向に沿って設けられるが、その流れ方
向に垂直な断面で見たときに、開孔率６０〜９０％、好
ましくは７０〜９０％で、１平方インチ（5.06ｃｍ2 )
当り３０〜７００個の、好ましく２００〜６００個の貫
通孔が設けられている。触媒は少なくとも該貫通孔の内
表面上に被覆されるが、その他支持基質の端面や側面に
被覆されていてもよい。支持基質上ヘの触媒の被覆方法
としては、バインダーを用いてまたはバインダーを使用
しないで、ウォッシュコート法やゾルゲル法が適用され
る。As the refractory material of the support substrate, ceramics such as α-alumina, mullite, cordierite, silicon carbide and the like, and metals such as austenitic and ferritic stainless steels are used. Conventional shapes such as honeycombs and foams can be used. Preferred are those made of cordierite and stainless steel, with a honeycomb-shaped support substrate. Although the supporting substrate is a large number of through holes are provided along the flow direction of the exhaust gas, when viewed in cross section perpendicular to its direction of flow, open porosity 60% to 90%, preferably 70 to 90% 1 square inch (5.06cm 2 )
Of 30 to 700 pieces per, that preferably 200 to 600 pieces of the through hole is provided. The catalyst is coated on at least the inner surface of the through-hole, but may be coated on the end face or side face of the support substrate. As a method for coating the catalyst on the support substrate, a wash coat method or a sol-gel method is used with or without a binder.
【００２２】触媒の支持基質上ヘの被覆量は、支持基質
単位体積当り２０〜２００ｇ／Ｌが好ましく、より好ま
しくは４０〜１４０ｇ／Ｌである。触媒の支持基質への
被覆量が20g/Ｌ未満の場合は脱硝性能は不十分となり、
200g/ Ｌを超えて多い場合は触媒の被覆に際し、貫通孔
の目づまりが起こりやすいので好ましくない。支持基質
単位体積当たりの銀の担持量は特に限定されないが、好
ましくは０．６〜１０ｇ／Ｌ、より好ましくは１．０〜
６．０ｇ／Ｌの範囲である。The coating amount of the catalyst on the supporting substrate is preferably 20 to 200 g / L, more preferably 40 to 140 g / L per unit volume of the supporting substrate. If the coating amount of the catalyst on the supporting substrate is less than 20 g / L, the denitration performance becomes insufficient,
If the amount exceeds 200 g / L, clogging of the through-holes is likely to occur when coating the catalyst, which is not preferable. The amount of silver supported per unit volume of the support substrate is not particularly limited, but is preferably 0.6 to 10 g / L, more preferably 1.0 to 1.0 g / L.
It is in the range of 6.0 g / L.
【００２３】耐火性支持基質上ヘの触媒粉末のウォッシ
ュコートは、例えば、触媒粉末にバインダーとしてアル
ミナゾルと脱イオン水を加えて混練し、スラリーを作
り、この中ヘ支持基質を浸漬し、取り出したものからエ
アーブローで余分のスラリーを除去し、その後乾燥、焼
成することにより行うことができる。また、支持基質の
貫通孔の内表面に予め本発明の触媒の活性アルミナから
なる被覆を形成した後、この活性アルミナに銀を担持し
て触媒被覆を形成してもよい。The wash coat of the catalyst powder on the refractory support substrate is, for example, kneaded by adding alumina sol and deionized water as a binder to the catalyst powder to form a slurry, into which the support substrate is dipped and taken out. Excess slurry can be removed from the material by air blow, followed by drying and firing. Further, after a coating made of activated alumina of the catalyst of the present invention is formed in advance on the inner surface of the through hole of the support substrate, silver may be supported on this activated alumina to form a catalyst coating.
【００２４】本発明の好ましい実施態様として、ハニカ
ム等の一体構造基質に触媒を彼覆して用いる場合、好ま
しい被覆量４０〜１４０ｇ／Ｌから計算される触媒換算
のガス接触時間は０．０３ｇ．ｓｅｃ／ｃｍ3 未満、好
ましくは０．０２ｇ．ｓｅｃ／ｃｍ3 以下である。In a preferred embodiment of the present invention, when the catalyst is applied to a monolithic substrate such as a honeycomb, the gas contact time in terms of the catalyst calculated from the preferable coating amount of 40 to 140 g / L is 0.03 g. sec / cm 3 , preferably 0.02 g. sec / cm 3 or less.
【００２５】本発明の脱硝方法においては、排気ガスの
触媒含有層入口ガス温度を４５０〜６００℃にに制御さ
れる。触媒含有層入口ガス温度が４５０℃未満では、本
発明の銀担持アルミナ触媒のＮＯｘ還元性能が効果的に
発揮されない。また、排気ガス温度が６００℃よりも高
温になると副反応であるＨＣの燃焼が優勢になりＨＣに
よるＮＯｘ還元の選択性が低下する。In the denitration method of the present invention, the temperature of the exhaust gas at the inlet of the catalyst-containing layer is controlled at 450 to 600 ° C. If the catalyst-containing layer inlet gas temperature is lower than 450 ° C., the NOx reduction performance of the silver-carrying alumina catalyst of the present invention will not be effectively exhibited. Further, when the exhaust gas temperature becomes higher than 600 ° C., the combustion of HC, which is a side reaction, becomes dominant, and the selectivity of NOx reduction by HC decreases.
【００２６】希薄空燃比で運転される内燃機関として
は、例えばガソリンリーンバーンエンジン及びディーゼ
ルエンジンが挙げられる。一般に、ガソリンリーンバー
ンエンジンの排気ガス中には、３〜８％のＯ2 と数百〜
数千ｐｐｍのＮＯｘとともに、数百〜数千ｐｐｍのＨＣ
及び数百〜数千ｐｐｍのＣＯ、数百〜数千ｐｐｍ程度の
Ｈ2 と数％〜１０％程度のＨ2 Ｏが含有される。また、
ディーゼルエンジンの排気ガス中には、８〜１６％程度
のＯ2 と数百〜千ｐｐｍ程度のＮＯｘと数十〜数百ｐｐ
ｍのＨＣ及びＣＯと数％〜１０％程度のＨ2 Ｏが含有さ
れる。このような排気ガスを上記の方法により本発明の
触媒と接触させることによって、ＮＯｘはＨＣ等の微量
存在する還元剤に依ってＮ2 とＨ2 Ｏにまで還元分解さ
れると同時にＨＣ等の還元剤もＣＯ2 とＨ2 Ｏとに酸化
される。ディーゼルエンジンの排気ガスのように、排気
ガスそのもののＨＣ／ＮＯｘ比が低い場合には、排気ガ
ス中にメタン換算濃度で数百〜数千ｐｐｍ程度の燃料Ｈ
Ｃを追加添加した後、本発明の触媒と接触させるシステ
ムを採用すれば充分なＮＯｘ除去率を達成できる。The internal combustion engine operated at a lean air-fuel ratio includes, for example, a gasoline lean burn engine and a diesel engine. Generally, the exhaust gas of a gasoline lean burn engine contains 3 to 8% O 2 and several hundred to
Hundreds to thousands of ppm of HC along with thousands of ppm of NOx
And hundreds to thousands ppm of CO, H 2 O of about several hundreds to several thousands of H 2 about ppm to several% to 10% is contained. Also,
In the exhaust gas of a diesel engine, about 8 to 16% of O 2 , about several hundred to about 1,000 ppm of NOx, and several tens to several hundred pp
HC and CO and a few percent to 10% of the of H 2 O m is contained. By bringing such exhaust gas into contact with the catalyst of the present invention by the above-mentioned method, NOx is reduced and decomposed to N 2 and H 2 O by a small amount of a reducing agent such as HC, and simultaneously, HC The reducing agent is also oxidized to CO 2 and H 2 O. When the HC / NOx ratio of the exhaust gas itself is low, such as the exhaust gas of a diesel engine, the fuel H has a concentration of about several hundreds to several thousands ppm in terms of methane in the exhaust gas.
A sufficient NOx removal rate can be achieved by employing the system of contacting the catalyst of the present invention after the additional addition of C.
【００２７】本発明の方法によれば、上述のような短い
接触時間（高い空間速度）で水分が共存する酸素過剰雰
囲気下でも、ＨＣによるＮＯｘの除去が効率良く進行す
る。According to the method of the present invention, the removal of NOx by HC proceeds efficiently even in the above-described short contact time (high space velocity) and in an oxygen-excess atmosphere where moisture coexists.
【００２８】[0028]
【実施例】以下に参考例、実施例及び比較例により、本
発明を更に詳細に説明する。但し、本発明は下記実施例
に限定されるものでない。The present invention will be described in more detail with reference to Reference Examples, Examples and Comparative Examples. However, the present invention is not limited to the following examples.
【００２９】〔実施例１〕３％銀担持アルミナ触媒被覆ハニカム（１）の製造 （ａ）比表面積（窒素吸着法にて測定、以下同様）１７
４ｍ2 ／ｇ、充填密度（水銀圧入法にて測定、以下同
様）０．７６ｇ／ｃｍ3 で、かつ真密度（水銀圧入法に
て測定、以下同様）１．６２ｇ／ｃｍ3 なるγ−アルミ
ナ粉末（アルミナＡとする）１００ｇを、硝酸銀４．９
ｇ（Ａｇ換算３．１ｇ）を含む脱イオン水水溶液1000mL
に浸漬し、攪拌しながら１００〜１１０℃に加熱し水分
を蒸発させた。更に空気中５００℃で３時間焼成し、３
％銀担持アルミナ触媒を得た。Example 1 Manufacture of honeycomb (1) coated with 3% silver-carrying alumina catalyst (a) Specific surface area (measured by nitrogen adsorption method, hereinafter the same) 17
4m 2 / g, (measured by mercury porosimetry, hereinafter the same) packing density 0.76 g / cm 3, and (measured by mercury porosimetry, hereinafter the same) true density 1.62 g / cm 3 comprising γ- alumina 100 g of powder (alumina A) was mixed with 4.9 silver nitrate.
g (3.1 g in terms of Ag) of deionized water (1000 mL)
And heated to 100 to 110 ° C. while stirring to evaporate water. Furthermore, baking at 500 ° C. for 3 hours in air
% Silver supported alumina catalyst was obtained.
【００３０】（ｂ）（ａ）で調製した銀担持アルミナ触
媒３０ｇをアルミナゾル（２０重量％アルミナ）１５ｇ
及び脱イオン水３０ｇとともにボールミルポットに仕込
み、湿式粉砕しスラリーを得た。このスラリーの中に、
市販の４００ｃｐｓｉ（セル／ｉｎｃｈ2 ）コージェラ
イトハニカム基質からくり貫かれた直径２．５４ｃｍ、
長さ６．３５ｃｍの円筒状コアを浸漬し、引上げ後、余
分のスラリーをエアーブローで除去し、乾燥した。その
後、５００℃で３０分焼成し、ハニカム１Ｌ（リット
ル）当たりドライ換算で１００ｇの固形分( 触媒：バイ
ンダーアルミナの重量比は10：1)を被覆した３％銀担持
アルミナ触媒被覆ハニカム（１）を得た。(B) 30 g of the silver-supported alumina catalyst prepared in (a) was mixed with 15 g of alumina sol (20% by weight alumina).
And 30 g of deionized water were charged into a ball mill pot and wet-pulverized to obtain a slurry. In this slurry,
2.54 cm diameter cut from commercial 400 cpsi (cell / inch 2 ) cordierite honeycomb substrate,
After immersing a cylindrical core having a length of 6.35 cm and pulling it up, excess slurry was removed by air blow and dried. Thereafter, the honeycomb was baked at 500 ° C. for 30 minutes, and coated with 3% silver-carrying alumina catalyst-coated honeycomb (1) coated with 100 g of solid content (weight ratio of catalyst: binder alumina: 10: 1) per 1 L (liter) of honeycomb. I got
【００３１】〔実施例２〕及び〔比較例１〕〜〔比較例
６〕３％銀担持アルミナ触媒被覆ハニカム（２）及び（３）
〜（８）の製造 実施例１において、アルミナＡの代わりに比表面積１３
０ｍ2 ／ｇ、充填密度０．７４ｇ／ｃｍ3 で、かつ真密
度１．３３ｇ／ｃｍ3 なるγ−アルミナ（アルミナ
Ｂ）、比表面積１０７ｍ2 ／ｇ、充填密度０．７８ｇ／
ｃｍ3 で、かつ真密度１．５９ｇ／ｃｍ3 なるγ−アル
ミナ（アルミナＣ）、比表面積２２３ｍ2 ／ｇ、充填密
度０．８９ｇ／ｃｍ3 で、かつ真密度２．３７ｇ／ｃｍ
3 なるγ−アルミナ（アルミナＤ）、比表面積２６７ｍ
2 ／ｇ、充填密度０．３７ｇ／ｃｍ3で、かつ真密度
０．８２ｇ／ｃｍ3 なるγ−アルミナ（アルミナＥ）、
比表面積１４９ｍ2 ／ｇ、充填密度０．５５ｇ／ｃｍ3
で、かつ真密度１．９５ｇ／ｃｍ3 なる活性アルミナ
（アルミナＦ）、比表面積９３ｍ2 ／ｇ、充填密度０．
５４ｇ／ｃｍ3 で、かつ真密度３．４２ｇ／ｃｍ3 なる
γ−アルミナ（アルミナＧ）及び比表面積２８１ｍ2 ／
ｇ、充填密度０．５８ｇ／ｃｍ3 で、かつ真密度２．７
0 ｇ／ｃｍ3 なるγ−アルミナ（アルミナＨ）の各々を
用いた以外は、実施例１と同様にして、それぞれ３％銀
担持アルミナ触媒被覆ハニカム（２）〔実施例２〕、３
％銀担持アルミナ触媒被覆ハニカム（３）〜（８）〔比
較例１〕〜〔比較例６〕を得た。[Example 2] and [Comparative Examples 1] to [Comparative Example 6] Honeycomb (2) and (3) coated with 3% silver-carrying alumina catalyst
In the production example 1 of (8) , the specific surface area 13
0 m 2 / g, packing density 0.74 g / cm 3, and a true density of 1.33 g / cm 3 comprising γ- alumina (alumina B), a specific surface area of 107m 2 / g, packing density 0.78 g /
In cm 3, and a true density of 1.59 g / cm 3 comprising γ- alumina (alumina C), a specific surface area of 223m 2 / g, a filling density of 0.89 g / cm 3, and a true density of 2.37 g / cm
3 gamma-alumina (alumina D), specific surface area 267m
2 / g, γ-alumina (alumina E) having a packing density of 0.37 g / cm 3 and a true density of 0.82 g / cm 3 ,
Specific surface area 149 m 2 / g, packing density 0.55 g / cm 3
Activated alumina (alumina F) having a true density of 1.95 g / cm 3 , a specific surface area of 93 m 2 / g, and a packing density of 0.
54 g / in cm 3, and becomes true density 3.42 g / cm 3 .gamma.-alumina (alumina G) and specific surface area 281m 2 /
g, packing density 0.58 g / cm 3 and true density 2.7
Except for using each of γ-alumina (alumina H) of 0 g / cm 3 , 3% silver-carrying alumina catalyst-coated honeycomb (2) [Example 2], 3
% Silver-supported alumina catalyst-coated honeycombs (3) to (8) [Comparative Example 1] to [Comparative Example 6] were obtained.
【００３２】〔実施例３〕および〔実施例４〕３％銀担持アルミナ触媒被覆ハニカム(9) 、(10)の製造 実施例１(b) において、ハニカム１Ｌあたりの３％銀担
持アルミナとバインダーアルミナとからなる固形分被覆
量をドライ換算で、それぞれ５０ｇおよび１５０ｇ( た
だし触媒：バインダーアルミナの重量比は10：1 で一定
とする。) に変えた以外は、実施例１と同様にして３％
銀担持アルミナ触媒被覆ハニカム(9) 〔実施例３〕およ
び(10)〔実施例４〕を得た。[Example 3] and [Example 4] Production of honeycombs (9) and (10) coated with 3% silver-carrying alumina catalyst In Example 1 (b), 3% silver-carrying alumina per 1 L of honeycomb and binder were used. The same procedures as in Example 1 were carried out except that the solid content of alumina was changed to 50 g and 150 g in dry conversion (however, the weight ratio of catalyst: binder alumina was kept constant at 10: 1). %
Silver-coated alumina catalyst-coated honeycomb (9) [Example 3] and (10) [Example 4] were obtained.
【００３３】〔実施例５〕５％銀担持アルミナ触媒被覆ハニカム(11)の製造 実施例１(a) においてアルミナＡ100 ｇを硝酸銀8.4 ｇ
（Ａｇ換算5.3 ｇ）を含む脱イオン水1000mLに浸漬した
以外は、実施例１(a) 同様にして５％銀担持アルミナ触
媒を得た。次いで実施例４と同様にしてハニカム１Ｌ当
りドライ換算で１５０ｇの固形分を被覆して５％銀担持
アルミナ触媒被覆ハニカム(11)を得た。Example 5 Preparation of Honeycomb (11) Coated with 5% Silver-Supported Alumina Catalyst In Example 1 (a), 100 g of alumina A was replaced with 8.4 g of silver nitrate.
A 5% silver-carrying alumina catalyst was obtained in the same manner as in Example 1 (a) except that the catalyst was immersed in 1000 mL of deionized water containing (5.3 g in terms of Ag). Next, in the same manner as in Example 4, the honeycomb was coated with 150 g of solid content in terms of dry weight per liter of honeycomb to obtain a 5% silver-carrying alumina catalyst-coated honeycomb (11).
【００３４】〔性能評価例１〕リーンバーンエンジン排気モデルガス評価（モードＩ） 内径３０ｍｍのステンレス製反応管に触媒被覆ハニカム
（１）を充填し常圧固定床反応装置に装着し、リーンバ
ーンエンジン排気モデルガスとして、ＮＯ５００ｐｐｍ
（以下、特に断らない限り、ガス成分濃度は容積濃度で
示す）、ＨＣとしてプロピレン５００ｐｐｍ、Ｏ2 ５
％、Ｈ2 Ｏ １０％、残部Ｎ2 からなる混合ガスを、標
準状態換算２０Ｌ／ｍｉｎの流量で通過させた。[Performance Evaluation Example 1] Lean-burn engine exhaust model gas evaluation (Mode I) A catalyst-coated honeycomb (1) was filled in a stainless steel reaction tube having an inner diameter of 30 mm and mounted on a normal-pressure fixed-bed reactor. 500ppm NO as exhaust model gas
(Hereinafter, unless otherwise specified, the gas component concentration is shown by volume concentration), 500 ppm of propylene as HC, O 2 5
%, H 2 O 10%, and a balance of N 2 were passed at a flow rate of 20 L / min in terms of standard condition.
【００３５】ハニカム体積当たりのガス空間速度は３
７，０００／ｈｒであり、ハニカムに被覆された触媒当
たりのガス接触時間は０．０１ｇ．ｓｅｃ／ｃｍ3 であ
った。触媒含有層入口ガス温度を３００℃から７００℃
まで、３０℃／ｍｉｎの昇温速度で連続的に昇温させな
がら反応管出口ガス中の各ガス成分濃度を連続測定し
た。The gas space velocity per honeycomb volume is 3
7,000 / hr, and the gas contact time per catalyst coated on the honeycomb was 0.01 g. sec / cm 3 . The temperature of the gas at the inlet of the catalyst-containing layer is 300 to 700 °
The concentration of each gas component in the gas at the outlet of the reaction tube was continuously measured while continuously increasing the temperature at a rate of 30 ° C./min.
【００３６】ＮＯとＮＯ2 の合計濃度は化学発光式ＮＯ
ｘ計で、Ｎ2 Ｏは非分散型赤外式Ｎ2 Ｏ計で、ＨＣはＦ
ＩＤ分析計でそれぞれ測定された。この触媒性能評価条
件をモードＩとする。モデルガスが触媒被覆ハニカムを
通過することにより反応ガス中のＮＯはＮ2 Ｏ及び／ま
たはＮ2 に転化されるが、触媒含有層入口ガス温度３０
０℃以上のガスが本発明の触媒被覆ハニカムを通過した
場合Ｎ2 Ｏは殆ど生成しないことが判明したので、本発
明の明細書では脱硝率（ＮＯ転化率）を以下の式で定義
した。The total concentration of NO and NO 2 is determined by chemiluminescence NO
x meter, N 2 O is a non-dispersive infrared N 2 O meter, HC is F
Each was measured with an ID analyzer. This catalyst performance evaluation condition is referred to as mode I. When the model gas passes through the catalyst-coated honeycomb, NO in the reaction gas is converted into N 2 O and / or N 2.
It has been found that when a gas at 0 ° C. or higher passes through the catalyst-coated honeycomb of the present invention, N 2 O is hardly generated. Therefore, in the specification of the present invention, the denitration rate (NO conversion rate) is defined by the following equation.
【００３７】 触媒被覆ハニカム（２）〜（11）についても同様にモー
ドＩのモデルガス評価を行った。表１に、触媒被覆ハニ
カム（１）〜（11）の各々について、使用されたアルミ
ナ担体の物性と性能評価モードＩにおける触媒含有層入
口ガス温度３００℃から７００℃の間での最大脱硝率Ｃ
ｍａｘ（％）とその時の温度Ｔｍａｘ（℃）を示す。本
発明の実施例の触媒被覆ハニカム（1)、 (2)、 (9)、
（10) および(11)は、それぞれＣｍａｘが４２．６％以
上と高い脱硝性能を示した。これに対し、比較例３の触
媒被覆ハニカム（５）に用いられた担体アルミナＢは公
知文献（Applied Catalysis B:Environmental,2(1993)1
99-205に使用されたものと同一のアルミナ担体である
が、これを用いた触媒被覆ハニカム（５）はモードＩの
条件ではＣｍａｘ３．５％しか示さなかった。[0037] Model I model gas evaluation was similarly performed on the catalyst-coated honeycombs (2) to (11). Table 1 shows, for each of the catalyst-coated honeycombs (1) to (11), the physical properties of the alumina support used and the maximum denitration ratio C at a catalyst-containing layer inlet gas temperature of 300 ° C to 700 ° C in the performance evaluation mode I.
It shows the maximum (%) and the temperature Tmax (° C.) at that time. Catalyst coated honeycombs (1), (2), (9),
(10) and (11) showed high denitration performance with Cmax of 42.6% or more, respectively. On the other hand, the carrier alumina B used for the catalyst-coated honeycomb (5) of Comparative Example 3 is disclosed in a known document (Applied Catalysis B: Environmental, 2 (1993) 1).
The same alumina support as used in 99-205, but the catalyst-coated honeycomb (5) using it showed only 3.5% Cmax under Mode I conditions.
【００３８】同様に、アルミナ担体Ｃ、Ｄ、Ｆ、Ｇ及び
Ｈを用いた触謀被覆ハニカム（３）、（４）、
（６）、（７）及び（８）も、それぞれ２０％以下と全
く不十分な脱硝率しか示さなかった。Similarly, a tentacle-coated honeycomb using the alumina carriers C, D, F, G and H (3), (4),
(6), (7) and (8) also showed a completely inadequate denitration rate of 20% or less, respectively.
【００３９】[0039]
【表１】 [Table 1]
【００４０】〔性能評価例２〕水分を含まないモデルガス評価（モードII） 性能評価例１において、１０％Ｈ2 Ｏを含まず、ＮＯ
５００ｐｐｍ、プロピレン５００ｐｐｍ、Ｏ2 ５％及び
残部Ｎ2 からなるドライの混合ガスを用いた以外は、性
能評価例１と同様にして、触媒被覆ハニカム（１）及び
（８）のそれぞれについて３００℃から７００℃におけ
る脱硝率を評価した（モードII）。[Performance Evaluation Example 2] Model gas evaluation without moisture (Mode II) In the performance evaluation example 1, NO containing 10% H 2 O, NO
Except for using a dry mixed gas composed of 500 ppm, 500 ppm of propylene, 5% of O 2, and the balance of N 2 , the catalyst-coated honeycombs (1) and (8) were heated from 300 ° C. in the same manner as in Performance Evaluation Example 1. The denitration rate at 700 ° C. was evaluated (mode II).
【００４１】図１に、比較例の触媒被覆ハニカム（８）
のモードＩとモードIIにおける脱硝率の触媒含有層入口
ガス温度依存性を示す。FIG. 1 shows a catalyst-coated honeycomb (8) of a comparative example.
4 shows the dependence of the denitration ratio on the gas temperature at the inlet of the catalyst-containing layer in Mode I and Mode II.
【００４２】図２に、実施例の触媒被覆ハニカム（１）
のモードＩとモードIIにおける脱硝率の触媒含有層入口
ガス温度依存性を示す。FIG. 2 shows a catalyst-coated honeycomb (1) of the embodiment.
4 shows the dependence of the denitration ratio on the gas temperature at the inlet of the catalyst-containing layer in Mode I and Mode II.
【００４３】図１から、比較例の触媒被覆ハニカム
（８）は、過剰酸素とＨＣとＮＯとを含むドライのモデ
ルガス評価モードIIではＴｍａｘ５１５℃においてＣｍ
ａｘ５６．１％と 充分高い脱硝率を示したが、モード
Ｉでは１０％以下と不十分な脱硝率しか示さず共存水蒸
気の脱硝性能に及ぽす影響が極めて顕著なことがわか
る。FIG. 1 shows that the catalyst-coated honeycomb (8) of the comparative example shows a Cm at Tmax of 515 ° C. in a dry model gas evaluation mode II containing excess oxygen, HC and NO.
Although the denitration rate was a sufficiently high at ax56.1%, the mode I showed only an insufficient denitration rate of 10% or less, indicating that the effect of coexisting steam on the denitration performance was extremely remarkable.
【００４４】これに対して、図２に示す実施例１の触媒
はモードIIのドライガス中（Ｃｍａｘ６６．１％、Ｔｍ
ａｘ５１２℃）では勿論のこと、モードＩの１０％水分
共存下でもＣｍａｘ５０．９％（Ｔｍａｘ５６１℃）
と、充分高い脱硝率を保持していた。On the other hand, the catalyst of Example 1 shown in FIG. 2 was used in dry gas of mode II (Cmax 66.1%, Tm
amax 512 ° C) and Cmax 50.9% (Tmax 561 ° C) even in the presence of 10% moisture in Mode I.
, A sufficiently high denitration rate was maintained.
【００４５】〔性能評価例３〕リーンバーンエンジン排気モデルガス評価（モードIII
） 性能評価例１において、実施例１の触媒（１）及び比較
例の触媒（５）のハニカムサイズを、それぞれ長さ６．
３５ｃｍから長さ３．８１ｃｍに切断して短くし、これ
に通じる混合ガスの組成をＮＯ ５００ｐｐｍ、プロピ
レン１，０００ｐｐｍ、Ｏ2 ５％、Ｈ2 Ｏ１０％及び残
部Ｎ2 ヘと変更したこと以外は、性能評価例１と同様に
して触媒（１）及び触媒（５）の脱硝率の温度依存性を
評価した。ハニカム換算のガス空間速度は６２，０００
／ｈｒ、ハニカムに被覆された触媒換算の接触時間は
０．００６ｇ．ｓｅｃ／ｃｍ3 であった。図３に触媒ハ
ニカム（１）及び（５）のモードIII における脱硝率の
温度依存性を示す。本発明の実施例の触媒（１）は、よ
り短い接触時間（より高い空間速度）でも優れた脱硝性
能を示すが、比較例の触媒（５）の性能は著しく低かっ
た。[Performance Evaluation Example 3]Lean burn engine exhaust model gas evaluation (Mode III
) In Performance Evaluation Example 1, the catalyst (1) of Example 1 and a comparison were made.
The honeycomb size of the catalyst (5) of the example was adjusted to a length of 6.
Cut from 35cm to 3.81cm in length and shorten
The composition of the gas mixture leading to
Len 1,000 ppm, OTwo5%, HTwoO10% and remaining
Part NTwoExcept for changing to F, the same as in Performance Evaluation Example 1
To determine the temperature dependence of the denitration rates of catalyst (1) and catalyst (5)
evaluated. The gas space velocity in terms of honeycomb is 62,000.
/ Hr, the contact time in terms of the catalyst coated on the honeycomb is
0.006 g. sec / cmThreeMet. Fig. 3 shows the catalyst
The denitration rate in mode III of the honeycombs (1) and (5)
Shows temperature dependence. The catalyst (1) of the embodiment of the present invention
Excellent denitration even with shorter contact time (higher space velocity)
Performance, but the performance of the catalyst (5) of Comparative Example was remarkably low.
Was.
【００４６】〔性能評価例４〕サーマルエージング前後の脱硝性能評価（モードIV） 性能評価例１において、リーンバーンエンジン排気モデ
ルガスとして、ＮＯ５００ｐｐｍ、プロビレン１，５０
０ｐｐｍ、Ｏ2 １０％、Ｈ2 Ｏ １０％、残部Ｎ2 から
なる混合ガスを用いたこと以外、性能評価例１と同様に
して実施例Ｉの触媒被覆ハニカム（１）のフレッシュ性
能を評価した（モードIV）。次いで、評価済み触媒被覆
ハニカムを取り出し、石英製の管状炉に充填し１０％Ｈ
2 Ｏ及び残部空気からなる混合ガス流通下、８００℃で
５時間サーマルエージングさせた。このサーマルエージ
ング後の触媒被覆ハニカム（１）を再び反応管に充填
し、モードIVで評価した。[Performance Evaluation Example 4] Denitration performance evaluation before and after thermal aging (Mode IV) In Performance Evaluation Example 1, NO 500 ppm, propylene 1,50 were used as lean burn engine exhaust model gas.
The fresh performance of the catalyst-coated honeycomb (1) of Example I was evaluated in the same manner as in Performance Evaluation Example 1, except that a mixed gas consisting of 0 ppm, 10% O 2, 10% H 2 O, and the balance N 2 was used. (Mode IV). Next, the evaluated catalyst-coated honeycomb was taken out, filled in a tube furnace made of quartz, and 10% H
Thermal aging was performed at 800 ° C. for 5 hours under a mixed gas flow of 2 O and the balance of air. The catalyst-coated honeycomb (1) after the thermal aging was filled again in the reaction tube, and evaluated in mode IV.
【００４７】図４に示すように、本発明の実施例の触媒
（１）は８００℃でのサーマルエージング後も水分共存
のリーンモデルガスに対して接触時間０．０１ｇ．ｓｅ
ｃ／ｃｍ3 （空間速度３７，０００／ｈｒ）の短い接触
時間（高空間速度）の条件下で高い脱硝性能を示した
（Ｃｍａｘ７３．０％、Ｔｍａｘ５３２℃）。As shown in FIG. 4, the catalyst (1) of the embodiment of the present invention has a contact time of 0.01 g. With respect to a lean model gas coexisting with water even after thermal aging at 800 ° C. se
Under the condition of short contact time (high space velocity) of c / cm 3 (space velocity 37,000 / hr), high denitration performance was exhibited (Cmax 73.0%, Tmax 532 ° C).
【００４８】[0048]
【発明の効果】以上の様に、本発明の脱硝触媒及び脱硝
方法によれば、水蒸気が共存する酸素過剰雰囲気下での
ＨＣによるＮＯｘの除去において、短い接触時間（高い
空間速度）でも高い脱硝率が得られ、実用性が高い。し
たがって、希薄空燃比で運転される内燃機関の排気ガス
の中のＮＯｘの除去に有用である。As described above, according to the denitration catalyst and the denitration method of the present invention, in the removal of NOx by HC in an oxygen-excess atmosphere in which water vapor coexists, high denitration can be achieved even with a short contact time (high space velocity). Rate and high practicality. Therefore, it is useful for removing NOx in the exhaust gas of an internal combustion engine operated at a lean air-fuel ratio.
【００４９】[0049]
【図１】比較例６の触媒のモードＩとモードIIにおける
脱硝率と触媒含有層入り口ガス温度との関係を示す図で
ある。FIG. 1 is a view showing a relationship between a denitration ratio and a catalyst-containing layer inlet gas temperature in a mode I and a mode II of a catalyst of Comparative Example 6.
【図２】実施例１の触媒のモードＩとモードIIにおける
脱硝率と触媒含有層入り口ガス温度との関係を示す図で
ある。FIG. 2 is a graph showing the relationship between the denitration ratio and the catalyst-containing layer inlet gas temperature in mode I and mode II of the catalyst of Example 1.
【図３】実施例１の触媒および比較例３の触媒のモード
III における脱硝率と触媒含有層入り口ガス温度との関
係を示す図である。FIG. 3 shows the mode of the catalyst of Example 1 and the catalyst of Comparative Example 3.
FIG. 6 is a diagram showing the relationship between the denitration rate and the gas temperature at the entrance of the catalyst-containing layer in III.
【図４】実施例１の触媒のフッレシェと８００℃エージ
ング後のモードIVにおける脱硝率と触媒含有層入り口ガ
ス温度との関係を示す図である。FIG. 4 is a graph showing the relationship between the denitration rate and the temperature of the gas at the inlet of the catalyst-containing layer in mode IV after aging at 800 ° C. with the catalyst of Example 1;
───────────────────────────────────────────────────── フロントページの続き (72)発明者 松田 高志 千葉県市川市国分４−18−16 (72)発明者 菅野 泰治 東京都足立区千住桜木２−17−１ (72)発明者 若林 正男 千葉県千葉市稲毛区作草部町609−４ (72)発明者 中村 良 千葉県市川市南八幡１−24−11 (56)参考文献 特開 昭55−129149（ＪＰ，Ａ) 特表 平６−509984（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B01J 21/00 - 38/74 B01D 53/86 B01D 53/94 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Matsuda 4-18-16 Kokubu, Ichikawa-shi, Chiba Prefecture (72) Inventor Taiji Kanno 2-17-1 Senju Sakuragi, Adachi-ku, Tokyo (72) Inventor Masao Wakabayashi Chiba 609-4, Sakusabe-cho, Inage-ku, Chiba-shi, Japan (72) Inventor Ryo Nakamura 1-24-11, Minami-Yawata, Ichikawa-shi, Chiba (56) References JP-A-55-129149 (JP, A) (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) B01J 21/00-38/74 B01D 53/86 B01D 53/94
Claims (6)
１２０ｍ2 ／ｇ以上で、水銀圧入法により測定された充
填密度が０．６０ｇ／ｃｍ3 以上で、かつ水銀圧入法に
より測定された真密度が１．８０ｇ／ｃｍ3 以下である
活性アルミナと、該活性アルミナに担持された銀とから
なる脱硝触媒。1. A specific surface area of at least 120 m 2 / g as measured by a nitrogen adsorption method, a packing density of at least 0.60 g / cm 3 as measured by a mercury intrusion method, and a true density measured by a mercury intrusion method. A denitration catalyst comprising activated alumina having a density of 1.80 g / cm 3 or less, and silver supported on the activated alumina.
支持基質と、該支持基質の少なくとも前記貫通孔の内表
面上に被覆された請求項１に記載の脱硝触媒とからな
り、前記貫通孔はその貫通の方向に垂直な断面で見たと
きに開孔率が６０〜９０％であり、貫通孔の数は5.06ｃ
ｍ 2 当り３０〜７００個であり、かつ該脱硝触媒の被覆
量が前記支持基質単位体積当り２０〜２００ｇ／Ｌであ
る脱硝触媒被覆構造体。2. A number of the supporting substrate made of a refractory material having a through hole consists of a denitration catalyst according to claim 1 wherein at least the coated on the inner surface of the through hole of the supporting substrate, wherein When the through hole is viewed in a cross section perpendicular to the direction of the penetration
And the number of through holes is 5.06 c.
a denitration catalyst-coated structure having 30 to 700 particles per m 2 and a coating amount of the denitration catalyst of 20 to 200 g / L per unit volume of the support substrate.
ガスを脱硝触媒含有層と接触させることからなる排気ガ
スの脱硝方法において、該脱硝触媒含有層に含まれる脱
硝触媒が請求項１に記載の脱硝触媒であり、かつ排気ガ
スが前記の脱硝触媒含有層の入口において４５０〜６０
０℃であることを特徴とする脱硝方法。3. A method for denitration of exhaust gas comprising contacting exhaust gas of an internal combustion engine operated at a lean air-fuel ratio with a denitration catalyst-containing layer, wherein the denitration catalyst contained in the denitration catalyst-containing layer is according to claim 1. The exhaust gas is 450 to 60 at the inlet of the denitration catalyst-containing layer.
A denitration method characterized by being at 0 ° C.
硝触媒含有層が請求項１の触媒で構成されている脱硝方
法。4. The denitration method according to claim 3, wherein said denitration catalyst-containing layer comprises the catalyst according to claim 1.
硝触媒含有層が請求項２の脱硝触媒被覆構造体で構成さ
れている脱硝方法。5. The denitration method according to claim 3, wherein the denitration catalyst-containing layer is constituted by the denitration catalyst coating structure according to claim 2.
であって、排気ガスを触媒含有層と、触媒換算で０．０
２ｇ．ｓｅｃ／ｃｍ3 以下の時間で接触させる脱硝方
法。6. The denitration method according to any one of claims 3 to 5, wherein the exhaust gas and the catalyst-containing layer are mixed with each other by 0.04 in terms of catalyst.
2g. A denitration method in which the contact is performed for a time of not more than sec / cm 3 .
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34430293A JP3155140B2 (en) | 1993-12-17 | 1993-12-17 | Denitration catalyst and denitration method |
| CA002138333A CA2138333A1 (en) | 1993-12-17 | 1994-12-16 | Nox removal catalyst and method of purifying exhaust gas by using the same |
| EP94119968A EP0658368A1 (en) | 1993-12-17 | 1994-12-16 | NOx removal catalyst and method of purifying exhaust gas by using the same |
| US08/358,373 US5559072A (en) | 1993-12-17 | 1994-12-19 | Nox removal catalyst and method of purifying exhaust gas by using the same |
| US08/463,889 US5609839A (en) | 1993-12-17 | 1995-06-05 | Nox removal catalyst and method of purifying exhaust gas by using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34430293A JP3155140B2 (en) | 1993-12-17 | 1993-12-17 | Denitration catalyst and denitration method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07171391A JPH07171391A (en) | 1995-07-11 |
| JP3155140B2 true JP3155140B2 (en) | 2001-04-09 |
Family
ID=18368194
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34430293A Expired - Fee Related JP3155140B2 (en) | 1993-12-17 | 1993-12-17 | Denitration catalyst and denitration method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3155140B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4658681B2 (en) * | 2005-05-17 | 2011-03-23 | 三菱重工業株式会社 | Denitration catalyst |
-
1993
- 1993-12-17 JP JP34430293A patent/JP3155140B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07171391A (en) | 1995-07-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR102427507B1 (en) | Palladium Diesel Oxidation Catalyst | |
| KR101846593B1 (en) | Nox storage catalyst with improved hydrocarbon conversion activity | |
| EP2611535B1 (en) | Catalyst for gasoline lean burn engines with improved no oxidation activity | |
| US7138358B2 (en) | Catalyzed diesel particulate matter filter with improved thermal stability | |
| EP1368107B1 (en) | A catalyzed diesel particulate matter exhaust filter | |
| EP2611536B1 (en) | Catalyst for gasoline lean burn engines with improved nh3-formation activity | |
| JP3155140B2 (en) | Denitration catalyst and denitration method | |
| JPH10174886A (en) | Waste gas cleaning catalyst layer, waste gas cleaning catalyst covered structural body and waste gas cleaning method | |
| JP3407262B2 (en) | Denitration catalyst and exhaust gas denitration method | |
| JPH11128688A (en) | Purification of waste gas | |
| JP3433500B2 (en) | Denitration catalyst and denitration method | |
| JP4058503B2 (en) | Exhaust gas purification catalyst layer, exhaust gas purification catalyst coating structure, and exhaust gas purification method using the same | |
| JPH11557A (en) | Catalyst layer for purification of exhaust gas, catalyst structural body for purification of exhaust gas and purifying method of exhaust gas using these | |
| CN117940205A (en) | Particulate filter with partially coated catalytic layer | |
| JP3682476B2 (en) | NOx removal catalyst, method for producing the same, and exhaust gas NOx removal method using the same | |
| JPH11128689A (en) | Purification of waste gas | |
| JP2000153133A (en) | Exhaust gas purification | |
| JPH10118489A (en) | Catalyst layer for purifying exhaust gas, catalyst structure for purifying exhaust gas, and method for purifying exhaust gas thereby | |
| JPH10286463A (en) | Catalytic layer for purification of exhaust gas, catalytic structure for purification of exhaust gas and method for purifying exhaust gas with the same | |
| JP2000070675A (en) | Exhaust gas cleaning method | |
| JPH1170338A (en) | Exhaust gas purifying catalyst layer, exhaust gas purifying catalyst coated structure and exhaust purifying process using structure | |
| JPH11104492A (en) | Exhaust gas purifying catalyst layer, exhaust gas purifying catalyst coated structure, and exhaust gas purifying process using the layer and the structure | |
| JP2000282856A (en) | Emission control method | |
| JPH10118502A (en) | Catalyst for purification of exhaust gas, structural body coated with the catalyst and method for purifying exhaust gas | |
| JPH10174887A (en) | Waste gas cleaning catalyst layer, waste gas cleaning catalyst covered structural body and waste gas cleaning method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |