JPH11107744A - Exhaust emission control catalyst device - Google Patents
Exhaust emission control catalyst deviceInfo
- Publication number
- JPH11107744A JPH11107744A JP9274297A JP27429797A JPH11107744A JP H11107744 A JPH11107744 A JP H11107744A JP 9274297 A JP9274297 A JP 9274297A JP 27429797 A JP27429797 A JP 27429797A JP H11107744 A JPH11107744 A JP H11107744A
- Authority
- JP
- Japan
- Prior art keywords
- honeycomb
- catalyst
- exhaust gas
- coat layer
- low
- 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.)
- Pending
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 122
- 239000007789 gas Substances 0.000 claims abstract description 54
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000001301 oxygen Substances 0.000 claims abstract description 12
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 12
- 150000002430 hydrocarbons Chemical class 0.000 claims description 55
- 229930195733 hydrocarbon Natural products 0.000 claims description 54
- 229910000510 noble metal Inorganic materials 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 16
- 239000000463 material Substances 0.000 claims description 13
- 238000011144 upstream manufacturing Methods 0.000 claims description 13
- 238000011068 loading method Methods 0.000 claims description 9
- 230000007423 decrease Effects 0.000 claims description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims 3
- 238000000746 purification Methods 0.000 abstract description 31
- 239000010970 precious metal Substances 0.000 abstract description 3
- 241000264877 Hippospongia communis Species 0.000 abstract 5
- 239000010410 layer Substances 0.000 description 39
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 34
- 239000000758 substrate Substances 0.000 description 24
- 239000002002 slurry Substances 0.000 description 14
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 10
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- 230000002829 reductive effect Effects 0.000 description 8
- 238000006722 reduction reaction Methods 0.000 description 7
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 6
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 6
- 229910017604 nitric acid Inorganic materials 0.000 description 6
- 239000012188 paraffin wax Substances 0.000 description 6
- 229910021536 Zeolite Inorganic materials 0.000 description 5
- 230000003197 catalytic effect Effects 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 238000010304 firing Methods 0.000 description 5
- 239000000446 fuel Substances 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 239000010457 zeolite Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000011247 coating layer Substances 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 239000010948 rhodium Substances 0.000 description 4
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 3
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 3
- 238000009835 boiling Methods 0.000 description 3
- 230000000052 comparative effect Effects 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
- 230000000694 effects Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000000873 masking effect Effects 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- IXSUHTFXKKBBJP-UHFFFAOYSA-L azanide;platinum(2+);dinitrite Chemical compound [NH2-].[NH2-].[Pt+2].[O-]N=O.[O-]N=O IXSUHTFXKKBBJP-UHFFFAOYSA-L 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- -1 that is Chemical compound 0.000 description 2
- 239000001993 wax Substances 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000006255 coating slurry Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 229910001657 ferrierite group Inorganic materials 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052680 mordenite Inorganic materials 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 229910000314 transition metal oxide Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ディーゼルエンジ
ンなどの内燃機関から排出される排ガスを浄化する排ガ
ス浄化用触媒装置に関し、さらに詳しくは、酸素過剰の
排ガス、すなわち排ガス中に含まれる一酸化炭素（Ｃ
Ｏ）、水素（Ｈ2 ）及び炭化水素（ＨＣ）等の還元性成
分を完全に酸化するのに必要な酸素量より過剰の酸素を
含む排ガスに、炭化水素（ＨＣ）を供給して窒素酸化物
（ＮＯx ）を効率よく還元浄化する排ガス浄化用触媒装
置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying catalyst device for purifying exhaust gas discharged from an internal combustion engine such as a diesel engine, and more particularly, to an exhaust gas containing excess oxygen, that is, carbon monoxide contained in the exhaust gas. (C
O), hydrogen (H 2 ) and hydrocarbons (HC) are supplied to the exhaust gas containing oxygen in excess of the amount of oxygen necessary to completely oxidize reducing components such as hydrocarbons (HC), and nitrogen (HC) is supplied to the exhaust gas. The present invention relates to an exhaust gas purifying catalyst device for efficiently reducing and purifying substances (NO x ).
【０００２】[0002]
【従来の技術】従来より、自動車の排ガス浄化用触媒と
して、ＣＯ及びＨＣの酸化とＮＯx の還元とを同時に行
って排ガスを浄化する三元触媒が用いられている。この
ような三元触媒としては、例えばコーディエライトなど
からなる耐熱性基材にγ−アルミナからなる多孔質担体
層を形成し、その多孔質担体層に白金（Ｐｔ）、ロジウ
ム（Ｒｈ）などの触媒貴金属を担持させたものが広く知
られている。2. Description of the Related Art Conventionally, a three-way catalyst for purifying exhaust gas by simultaneously oxidizing CO and HC and reducing NO x has been used as a catalyst for purifying exhaust gas of automobiles. As such a three-way catalyst, for example, a porous carrier layer made of γ-alumina is formed on a heat-resistant substrate made of cordierite or the like, and platinum (Pt), rhodium (Rh), or the like is formed on the porous carrier layer. What carried the catalyst noble metal is widely known.
【０００３】一方、近年、地球環境保護の観点から、自
動車などの内燃機関から排出される排ガス中の二酸化炭
素（ＣＯ2 ）が問題とされ、その解決策として空燃比
（Ａ／Ｆ）が拡大された酸素過剰雰囲気において希薄燃
焼させる、いわゆるリーンバーンが採用されている。こ
のリーンバーンにおいては、燃費が向上するために燃料
の使用が低減され、その燃焼排ガスであるＣＯ2 の発生
を抑制することができる。On the other hand, in recent years, carbon dioxide (CO 2 ) in exhaust gas discharged from internal combustion engines such as automobiles has become a problem from the viewpoint of protection of the global environment, and the air-fuel ratio (A / F) has been expanded as a solution to this problem. What is called lean burn, in which lean combustion is performed in a reduced oxygen-excess atmosphere, is employed. In this lean burn, the use of fuel is reduced to improve fuel efficiency, and the generation of CO 2 , which is the combustion exhaust gas, can be suppressed.
【０００４】しかしながら従来の三元触媒は、空燃比が
理論空燃比（ストイキ）近傍において排ガス中のＣＯ，
ＨＣ，ＮＯx を同時に酸化・還元し、浄化するものであ
って、この三元触媒では、リーンバーンやディーゼルエ
ンジンの排ガスのような酸素過剰雰囲気下におけるＮＯ
x の還元除去が困難である。そこで、例えばリーンバー
ンエンジンでは、パルス状にリッチ雰囲気とすること
で、リッチ時にＨＣとＮＯx を反応させてＮＯx の還元
効率を向上させる方法が行われている。またディーゼル
エンジンでは、排ガス中に還元剤として軽油やプロパン
などのＨＣを添加し、ＮＯx の還元効率を向上させるこ
とが行われている。However, in the conventional three-way catalyst, when the air-fuel ratio is near the stoichiometric air-fuel ratio (stoichiometric), CO,
HC, NO x and simultaneously oxidizing and reducing been made to purify, in this three-way catalyst, NO in an excess oxygen atmosphere such as exhaust gas of lean-burn and diesel engines
It is difficult to remove x by reduction. Therefore, for example, in the lean-burn engine, by a rich atmosphere in pulses, a method for improving the reduction efficiency of the NO x is reacted with HC and NO x in the rich time is performed. In the diesel engine, the addition of HC such as light oil and propane as reducing agent into the exhaust gas, to improve the reduction efficiency of the NO x is being performed.
【０００５】[0005]
【発明が解決しようとする課題】ところが酸素過剰な排
ガス中にＨＣを添加する方法では、触媒上流側からＨＣ
を添加すると、触媒の上流側端面でＮＯx 還元反応が進
行し、それに伴ってＨＣの酸化反応も活発に生じる。そ
のため、ＨＣが触媒下流側に供給できなくなり、ＨＣの
利用効率が低下してＨＣの添加量に見合ったＮＯx 浄化
能が得られないという不具合がある。However, in the method of adding HC to exhaust gas containing excess oxygen, HC is added from the upstream side of the catalyst.
When NO is added, the NO x reduction reaction proceeds on the upstream end face of the catalyst, and the oxidation reaction of HC is also actively generated. For this reason, there is a problem that HC cannot be supplied to the downstream side of the catalyst, the utilization efficiency of HC is reduced, and the NO x purification ability corresponding to the added amount of HC cannot be obtained.
【０００６】この不具合を解決するには、複数の触媒を
排ガス流れ方向に対して直列に配置し、その触媒間でＨ
Ｃを添加する方法（分割添加）がある。しかしこの方法
では、ＨＣ添加部の増加により制御が煩雑となり、装置
的にも複雑となる。また、一般に行われているシリンダ
筒内に排気行程でＨＣを添加する方法（筒内添加）に対
しては、分割添加を適用することができない。In order to solve this problem, a plurality of catalysts are arranged in series in the exhaust gas flow direction, and H
There is a method of adding C (split addition). However, in this method, the control becomes complicated due to the increase in the number of HC addition units, and the apparatus becomes complicated. In addition, split addition cannot be applied to a method of adding HC into a cylinder cylinder, which is generally performed in an exhaust stroke (in-cylinder addition).
【０００７】一方、筒内添加の場合にはＨＣ種が軟質化
されるため、酸化される温度が低温域へ移行してＮＯx
浄化反応域以下の温度でＨＣが酸化されてしまい、ＮＯ
x 還元反応におけるＨＣの利用効率が低下するという不
具合がある。本発明はこのような事情に鑑みてなされた
ものであり、還元剤であるＨＣを分割添加しなくともＨ
Ｃの利用効率を増大させ、ＮＯx 浄化能をさらに向上さ
せることを目的とする。On the other hand, in the case of in-cylinder addition, since the HC species is softened, the oxidizing temperature shifts to a low temperature range and NO x
HC is oxidized at a temperature below the purification reaction zone, and NO
There is a problem that the use efficiency of HC in the x reduction reaction is reduced. The present invention has been made in view of such circumstances, and it is possible to reduce the amount of H without dividing HC as a reducing agent.
An object is to increase the utilization efficiency of C and further improve the NO x purification ability.
【０００８】[0008]
【課題を解決するための手段】上記課題を解決する請求
項１に記載の排ガス浄化用触媒装置の特徴は、酸素を過
剰に含む排ガス中に炭化水素を供給して排ガス中に含ま
れる窒素酸化物を還元浄化するのに用いられ、複数のハ
ニカム触媒を排ガス流れ方向に対して直列に配置してな
る排ガス浄化用触媒装置であって、複数のハニカム触媒
のうち最下流部に配置されたハニカム触媒を除く少なく
とも１個のハニカム触媒の一部に、貴金属の担持量が少
ない低担持領域をハニカム軸方向に連続して設けたこと
にある。According to a first aspect of the present invention, there is provided a catalyst device for purifying exhaust gas, which comprises supplying hydrocarbons to an exhaust gas containing an excessive amount of oxygen, thereby oxidizing nitrogen contained in the exhaust gas. An exhaust gas purifying catalyst device used for reducing and purifying substances, wherein a plurality of honeycomb catalysts are arranged in series with respect to an exhaust gas flow direction, and the honeycomb arranged at the most downstream portion of the plurality of honeycomb catalysts One of the at least one honeycomb catalyst excluding the catalyst is that a low-loading region having a low noble metal loading is provided continuously in the honeycomb axial direction.
【０００９】また請求項２に記載の排ガス浄化用触媒装
置の特徴は、請求項１に記載の排ガス浄化用触媒装置に
おいて、低担持領域はハニカム担体基材のみから構成さ
れていることにある。さらに請求項３に記載の排ガス浄
化用触媒装置の特徴は、請求項１に記載の排ガス浄化用
触媒装置において、複数のハニカム触媒は、排ガス流れ
方向の上流から下流に向かって低担持領域が少なくなっ
ていることにある。The exhaust gas purifying catalyst device according to the second aspect is characterized in that, in the exhaust gas purifying catalytic device according to the first aspect, the low-loading region is formed only of the honeycomb carrier base material. Further, a feature of the exhaust gas purifying catalyst device according to claim 3 is that, in the exhaust gas purifying catalyst device according to claim 1, the plurality of honeycomb catalysts have less low carrying regions from upstream to downstream in the exhaust gas flow direction. It has become.
【００１０】[0010]
【発明の実施の形態】請求項１に記載の排ガス浄化用触
媒装置では、複数のハニカム触媒のうち最下流部に配置
されたハニカム触媒を除く少なくとも１個のハニカム触
媒の一部に、貴金属の担持量が少ない低担持領域をハニ
カム軸方向に連続して設けている。すなわち、排ガスは
先ず上流側のハニカム触媒に流入し、担持されている貴
金属の触媒作用により排ガス中のＨＣはＮＯx との反応
と自らの酸化とにより消費される。しかし一部の排ガス
は低担持領域を通過し、低担持領域を通過した排ガスに
おいてはＨＣはほとんど酸化されず、そのまま下流側の
ハニカム触媒に流入する。そして最下流部に配置された
ハニカム触媒には低担持領域が存在しない。したがっ
て、下流側のハニカム触媒でもＨＣがＮＯx の還元に消
費され、最下流部のハニカム触媒ではＨＣが完全に消費
される。これによりＨＣの利用効率が向上する。In the exhaust gas purifying catalyst device according to the first aspect of the present invention, at least a portion of at least one of the plurality of honeycomb catalysts, excluding the one located at the most downstream side, contains a precious metal. A low carrying area having a small carrying amount is provided continuously in the honeycomb axial direction. That is, the exhaust gas first flows into the honeycomb catalyst on the upstream side, and the HC in the exhaust gas is consumed by the reaction with NO x and the oxidation thereof by the catalytic action of the supported noble metal. However, part of the exhaust gas passes through the low-loading region, and HC is hardly oxidized in the exhaust gas having passed through the low-loading region, and flows into the downstream honeycomb catalyst as it is. And the honeycomb catalyst arranged at the most downstream part does not have a low carrying area. Therefore, HC in the downstream side of the honeycomb catalyst is consumed in the reduction of NO x, HC in the honeycomb catalyst of the most downstream portion is completely consumed. Thereby, the utilization efficiency of HC is improved.
【００１１】また、下流側の触媒ほど流入する排ガス温
度が低い。したがってＨＣは酸素による酸化よりもＮＯ
x との反応が優先的に生じるようになり、ＨＣの利用効
率が向上してＮＯx 浄化率が向上する。低担持領域にお
ける貴金属の担持量は、通常の担持量の１／１０以下で
あることが望ましく、また無担持とすることもできる。
低担持領域における貴金属の担持量が通常の担持量の１
／１０を超えると、低担持とした効果が得られずＨＣの
利用効率が低下してＮＯx 浄化能が低下する。The temperature of the exhaust gas that flows in the downstream side of the catalyst is lower. Thus HC is more NO than oxidation by oxygen
The reaction with x occurs preferentially, the HC utilization efficiency is improved, and the NO x purification rate is improved. The supported amount of the noble metal in the low supported region is desirably 1/10 or less of the normal supported amount, and may be unsupported.
The supported amount of the noble metal in the low supported area is 1 of the normal supported amount.
When / exceeds 10, NO x purification performance efficiency of HC not be obtained the effect that the lower bearing is reduced is reduced.
【００１２】またハニカム触媒が３個以上の複数個用い
られる場合には、請求項３に記載のように、複数のハニ
カム触媒は排ガス流れ方向の上流から下流に向かって低
担持領域が少なくなるように傾斜した構成することが好
ましい。このようにすればＨＣの利用効率が一層向上す
る。低担持領域は、ハニカム軸方向に連続して設けられ
れば、ハニカム触媒におけるその位置は特に制限されな
い。例えば軸中心に対して同心円状、市松模様状、軸中
心に対して対称形状などとすることができる。なかで
も、低担持領域は軸中心に集中して設けることが好まし
い。軸中心は排ガスの流速が大きいので、軸中心に低担
持領域を設けることにより、多量のＨＣが下流側の触媒
に流入する。したがって下流側の触媒では、入りガス温
度が低下してＮＯx が浄化されやすくなっている雰囲気
中に多量のＨＣが供給されることとなり、ＨＣ利用効率
が向上してＮＯx 浄化率が一層向上する。また軸中心に
集中して設ける方法であれば、マスキングの形成も用意
となり低担持領域の形成が容易である。In the case where three or more honeycomb catalysts are used, the plurality of honeycomb catalysts have such a structure that the low carrying area decreases from upstream to downstream in the exhaust gas flow direction. It is preferable to have a configuration that is inclined. In this way, the utilization efficiency of HC is further improved. As long as the low carrying region is provided continuously in the honeycomb axial direction, its position in the honeycomb catalyst is not particularly limited. For example, the shape may be concentric with the axis center, checkered, symmetrical with respect to the axis center, or the like. In particular, it is preferable that the low carrying region is provided concentrated on the center of the shaft. Since the flow velocity of the exhaust gas is large at the shaft center, a large amount of HC flows into the downstream catalyst by providing the low-loading region at the shaft center. Downstream of the catalyst is therefore the gas temperature is decreased NO x becomes the large amount of HC into the atmosphere that is easily cleaned is supplied, NO x purification ratio is improved HC utilization efficiency further improved enters I do. In addition, if the method is provided so as to be concentrated on the center of the shaft, the formation of the masking is also easy, and the formation of the low carrying region is easy.
【００１３】低担持領域には、Ｆｅ，Ｍｎ，Ｃｅなどの
金属元素を担持することも好ましい。これによりＨＣの
酸化を抑制しつつＮＯをＮＯ2 に酸化することができ
る。ＮＯx の還元反応はＮＯ2 が還元される反応が主体
であるので、ＮＯ2 を多く生成しつつＨＣの酸化を抑制
することによりＮＯx 浄化能が一層向上する。ハニカム
触媒は一般に、ハニカム担体基材と、多孔質酸化物より
なり基材表面に形成されたコート層と、コート層に担持
された貴金属とから構成されているが、低担持領域はコ
ート層をもたずハニカム担体基材のみから構成すること
も好ましい。貴金属はハニカム担体基材には担持されな
いので、低担持領域とする部分にコート層を形成しない
でおくことにより、貴金属溶液に浸漬して行う貴金属担
持工程を、マスキングの必要なく従来と同様に行うこと
ができ製造が容易である。[0013] It is also preferable that a metal element such as Fe, Mn, or Ce is supported in the low supporting area. This makes it possible to oxidize NO to NO 2 while suppressing the oxidation of HC. Since the reduction reaction of the NO x is the principal reaction in which NO 2 is reduced, NO x purification performance is further improved by inhibiting the oxidation of HC while generating much NO 2. The honeycomb catalyst is generally composed of a honeycomb carrier substrate, a coat layer formed of a porous oxide and formed on the substrate surface, and a noble metal supported on the coat layer. It is also preferable to use a honeycomb carrier substrate alone. Since the noble metal is not supported on the honeycomb carrier substrate, the noble metal supporting step performed by immersing in the noble metal solution is performed in the same manner as in the related art without masking by not forming a coat layer in a portion to be a low supporting region. Can be manufactured easily.
【００１４】ハニカム担体基材としては、コーディエラ
イトなどの耐熱性セラミックスから形成されたモノリス
担体基材、金属箔製の平板と波板を重ねて交互に巻回す
ることで形成されたメタル担体基材などが利用できる。
コート層を形成する多孔質酸化物としては、アルミナ、
シリカ、チタニア、ジルコニア、シリカ−アルミナ、チ
タニア−ジルコニア、ゼオライトなどから選ばれる少な
くとも一種を用いることができる。アルミナにはα−ア
ルミナ、γ−アルミナなどを用いることができる。As the honeycomb carrier substrate, a monolith carrier substrate made of a heat-resistant ceramic such as cordierite, or a metal carrier formed by stacking and alternately winding a metal foil flat plate and a corrugated plate are used. Substrates and the like can be used.
As the porous oxide forming the coat layer, alumina,
At least one selected from silica, titania, zirconia, silica-alumina, titania-zirconia, zeolite, and the like can be used. As the alumina, α-alumina, γ-alumina, or the like can be used.
【００１５】コート層を形成する多孔質酸化物には、Ｈ
Ｃの吸着能に優れたゼオライトを含むことが好ましい。
このゼオライトとしては、モルデナイト、ＺＳＭ−５、
ＵＳＹ、フェリエライト、ゼオライトベータなどがＨＣ
の吸着量が多く、これらの少なくとも一種を用いること
が望ましいが、特にこれらに限定されるものではない。The porous oxide forming the coat layer includes H
It is preferable to include a zeolite having excellent C adsorption ability.
As this zeolite, mordenite, ZSM-5,
USY, ferrierite, zeolite beta, etc. are HC
It is desirable to use at least one of these, but the present invention is not particularly limited thereto.
【００１６】コート層を形成する多孔質酸化物には、酸
素吸蔵放出能を有する酸化物を含むことも好ましい。こ
れによりＨＣが活性化され低温域におけるＮＯx 浄化能
が向上する。このような酸化物としては、ＣｅＯ2 、Ｐ
ｒＯ4 などの希土類金属酸化物、ＮｉＯ、Ｆｅ2 Ｏ3 、
ＣｕＯ、Ｍｎ2 Ｏ5 などの遷移金属酸化物などを用いる
ことができる。The porous oxide forming the coat layer preferably contains an oxide having an oxygen storage / release capability. As a result, HC is activated, and the NO x purification performance in a low temperature range is improved. Such oxides include CeO 2 , P
rare earth metal oxides such as rO 4 , NiO, Fe 2 O 3 ,
Transition metal oxides such as CuO and Mn 2 O 5 can be used.
【００１７】この酸素吸蔵放出能を有する酸化物は、多
孔質酸化物１００重量部に対して１０〜４００重量部の
割合で混合することが好ましい。酸素吸蔵放出能を有す
る酸化物の混合割合が１０重量部より少ないと、ＨＣの
活性化が困難となり低温域におけるＮＯx 浄化能の向上
が望めない。また４００重量部より多く混合すると触媒
活性が低下する。It is preferable that the oxide having the oxygen storage / release capability is mixed at a ratio of 10 to 400 parts by weight with respect to 100 parts by weight of the porous oxide. If the mixing ratio of the oxide having oxygen storage capacity is less than 10 parts by weight, it is not expected improvement of the NO x purifying ability in low temperature range becomes difficult activation of HC. Further, when the amount is more than 400 parts by weight, the catalytic activity decreases.
【００１８】貴金属としては、白金（Ｐｔ）、パラジウ
ム（Ｐｄ）、ロジウム（Ｒｈ）、イリジウム（Ｉｒ）の
少なくとも一種を用いることができる。この貴金属の担
持量は、触媒１リットルに対して０．０１〜３０ｇの範
囲が望ましい。０．０１ｇ未満ではＮＯx をほとんど浄
化できず、３０ｇより多く担持してもＮＯx 浄化活性が
飽和するため、それ以上の担持はコストの増大を招くだ
けである。As the noble metal, at least one of platinum (Pt), palladium (Pd), rhodium (Rh) and iridium (Ir) can be used. The amount of the noble metal carried is desirably in the range of 0.01 to 30 g per liter of the catalyst. If the amount is less than 0.01 g, NO x can hardly be purified. Even if the amount is more than 30 g, the NO x purification activity is saturated.
【００１９】排ガスに添加されるＨＣとしては、その種
類は特に制限されない。具体的な炭化水素化合物として
は、軽油や灯油が代表的に例示される。ＨＣの添加量
は、ディーゼルエンジンの場合、排ガス中に１０〜１０
０００ｐｐｍＣの範囲が好ましい。１０ｐｐｍＣより少
ないとＮＯx の浄化が困難となり、１００００ｐｐｍＣ
以上添加してもＮＯx 浄化能が飽和するとともにＨＣが
排出されるようになる。なお、ＨＣは排ガス中に直接添
加してもよいし、シリンダ筒内に排気行程において添加
することもできる。The type of HC added to the exhaust gas is not particularly limited. Typical examples of the hydrocarbon compound include light oil and kerosene. In the case of a diesel engine, the amount of HC added is 10 to 10 in the exhaust gas.
A range of 000 ppmC is preferred. If it is less than 10 ppmC, it becomes difficult to purify NO x and it becomes 10,000 ppmC
Even with the above addition, the NO x purification ability is saturated and HC is discharged. Note that HC may be added directly into the exhaust gas or may be added into the cylinder cylinder during the exhaust stroke.
【００２０】低担持領域を形成するには、大別して以下
の３つの方法がある。 （１）組合せ法 貴金属を担持したハニカム触媒と、貴金属を担持しない
又は僅かに担持したハニカム触媒とをそれぞれ切断して
組合せることで、低担持領域をもつハニカム触媒を製造
することができる。There are roughly the following three methods for forming the low carrying region. (1) Combination method A honeycomb catalyst having a low supported region can be manufactured by cutting and combining a honeycomb catalyst supporting a noble metal and a honeycomb catalyst not supporting or slightly supporting a noble metal.
【００２１】但しこの方法では、メタル担体基材から形
成されたハニカム触媒を用いることが困難であり、モノ
リス担体基材から形成されたハニカム触媒のみに適用で
きる。 （２）無コート部を形成する方法１ ハニカム担体基材のコートを行わない部分を端面からマ
スクしておき、コーティング用スラリー中に浸漬して引
き上げ、マスクを外し乾燥・焼成してコート層を形成す
る。コート層はマスクされていないハニカム通路表面の
みに形成され、マスクされていた部分のハニカム通路表
面はハニカム担体基材から構成されている。However, in this method, it is difficult to use a honeycomb catalyst formed from a metal support substrate, and the method can be applied only to a honeycomb catalyst formed from a monolith support substrate. (2) Method 1 for forming uncoated portion A portion of the honeycomb carrier substrate where no coating is to be performed is masked from the end face, dipped in a slurry for coating, pulled up, removed from the mask, dried and fired to form a coated layer. Form. The coat layer is formed only on the unmasked honeycomb passage surface, and the masked portion of the honeycomb passage surface is formed of a honeycomb carrier base material.
【００２２】その後、全体を貴金属溶液に浸漬し、引き
上げて乾燥・焼成することで貴金属を担持する。貴金属
はコート層にのみ担持されるので、ハニカム担体基材か
らなるハニカム通路には貴金属が担持されず低担持領域
が形成される。 （３）無コート部を形成する方法２ メタル担体基材のコートを行わない部分を端面からマス
クしておき、アルミナスラリー中に浸漬して引き上げ、
乾燥・焼成してアルミナからなるプレコートを形成す
る。次にマスクを外し、全体をゼオライトを含むコーテ
ィング用スラリー中に浸漬して引き上げ、乾燥・焼成し
てコート層を形成する。プレコートの無い部分では、焼
成時にコート層がメタル担体基材から剥離して脱落し、
メタル担体基材が表出する。Thereafter, the whole is immersed in a noble metal solution, pulled up, dried and fired to carry the noble metal. Since the noble metal is supported only on the coat layer, the noble metal is not supported on the honeycomb passage made of the honeycomb carrier base material, and a low-supporting region is formed. (3) Method 2 for forming uncoated portion A portion of the metal carrier substrate where no coating is to be performed is masked from the end face, immersed in alumina slurry and pulled up.
Drying and firing are performed to form a precoat made of alumina. Next, the mask is removed, the whole is dipped in a coating slurry containing zeolite, pulled up, dried and fired to form a coat layer. In the part without the pre-coat, the coat layer peels off from the metal carrier base material during firing and falls off,
The metal carrier substrate is exposed.
【００２３】その後、（２）と同様に貴金属を担持する
ことで、低担持領域が形成される。 （４）無コート部を形成する方法３ ハニカム担体基材のコートを行う部分を端面からマスク
し、残りの部分に高沸点パラフィンなどをコートする。
次にマスクを外し、全体をコーティング用スラリー中に
浸漬して引き上げ、乾燥・焼成してコート層を形成す
る。この焼成時にパラフィンが溶融するので、その表面
に形成されていたコート層が剥離して脱落し、ハニカム
担体基材が表出するため、マスクされていた部分にのみ
コート層が形成される。Thereafter, a noble metal is supported in the same manner as in (2), thereby forming a low-supporting region. (4) Method 3 for forming uncoated portion The portion of the honeycomb carrier substrate to be coated is masked from the end face, and the remaining portion is coated with high-boiling paraffin or the like.
Next, the mask is removed, the whole is immersed in a slurry for coating, pulled up, dried and fired to form a coat layer. Since the paraffin melts during this firing, the coat layer formed on the surface is peeled off and falls off, and the honeycomb carrier base material is exposed, so that the coat layer is formed only on the masked portion.
【００２４】その後、（２）と同様に貴金属を担持する
ことで、低担持領域が形成される。 （５）無担持部を形成する方法１ ハニカム担体基材の全面にコート層を形成する。そして
低担持領域とする部分を端面からマスクし、（２）と同
様に貴金属を担持する。これにより、マスクされていた
部分に低担持領域が形成される。 （６）無担持部を形成する方法２ ハニカム担体基材の全面にコート層を形成する。そして
貴金属を担持する部分を端面からマスクし、残りの部分
の端面に表出するハニカムセルの開口を高沸点パラフィ
ンなどで目詰めする。Thereafter, a noble metal is supported in the same manner as in (2) to form a low-supporting region. (5) Method 1 for Forming Non-Supported Part A coat layer is formed on the entire surface of the honeycomb carrier base material. Then, a portion to be a low supporting region is masked from the end face, and a noble metal is supported as in (2). As a result, a low-carrying region is formed in the masked portion. (6) Method 2 for forming non-supporting portion A coat layer is formed on the entire surface of the honeycomb carrier substrate. Then, the portion supporting the noble metal is masked from the end face, and the opening of the honeycomb cell exposed on the end face of the remaining portion is plugged with high boiling point paraffin or the like.
【００２５】次にマスクを外し、（２）と同様に貴金属
を担持する。この時の焼成時に目詰めのパラフィンが溶
融してハニカムセルが開口し、低担持領域が形成され
る。Next, the mask is removed, and a noble metal is supported as in (2). At the time of firing at this time, the plugged paraffin melts to open the honeycomb cells, thereby forming a low-carrying region.
【００２６】[0026]
【実施例】以下、実施例及び比較例により本発明を具体
的に説明する。 （実施例１）図１に本実施例の触媒装置の概略構成を示
す。この触媒装置は、排ガス流の上流側から下流側へ向
かって触媒Ａ、触媒Ｓ、触媒Ｓの順で直列に３個のハニ
カム触媒が配置されている。このうち触媒Ａでは、中心
軸を中心とし全体の容積の１／２の部分にＰｔが担持さ
れていない無担持領域ａが形成され、２番目及び３番目
に配置された触媒Ｓでは、Ｐｔは全体に均一に担持され
ている。 ＜触媒の調製＞コーディエライト製で、容積０．７Ｌの
円柱状ハニカム担体基材を用意した。The present invention will be specifically described below with reference to examples and comparative examples. (Embodiment 1) FIG. 1 shows a schematic configuration of a catalyst device of this embodiment. In this catalyst device, three honeycomb catalysts are arranged in series in the order of catalyst A, catalyst S, and catalyst S from the upstream side to the downstream side of the exhaust gas flow. Among them, in the catalyst A, a non-supporting area a where Pt is not supported is formed in a half of the entire volume around the center axis, and in the catalyst S arranged second and third, Pt is It is carried uniformly throughout. <Preparation of Catalyst> A columnar honeycomb carrier substrate having a capacity of 0.7 L made of cordierite was prepared.
【００２７】一方、ゼオライト（モルデナイト３０）粉
末１５０重量部、アルミナ粉末７５重量部、アルミナゾ
ル（固形分４０％）９０重量部、水３００重量部を混合
してスラリーを調製した。そしてハニカム担体基材全体
をスラリーに浸漬し、引き上げて余分なスラリーを吹き
払った後、乾燥・焼成してコート層を形成した。この工
程を２回行い、ハニカム担体基材１Ｌ当たり１００ｇの
コート層を形成した。On the other hand, a slurry was prepared by mixing 150 parts by weight of zeolite (mordenite 30) powder, 75 parts by weight of alumina powder, 90 parts by weight of alumina sol (solid content: 40%) and 300 parts by weight of water. Then, the entire honeycomb carrier base material was immersed in the slurry, pulled up to blow off excess slurry, and then dried and fired to form a coat layer. This step was performed twice to form a coat layer of 100 g per liter of the honeycomb carrier substrate.
【００２８】次に図２に示すように、コート層が形成さ
れたハニカム担体基材１の両端面の中心軸を中心として
面積が端面面積の１／２の円形部分に、ゴムシートを用
いてマスク１０を形成した。そして高沸点パラフィン
（ロウ）の溶湯に両端面を漬けて引き上げることで、マ
スク１０の外側の同心円部分１１のセルの開口の目詰め
を行った。なおメタル担体の場合には、マグネットシー
トを無担持領域の端面に置き、上からスラリーを流し込
み、余分なスラリーを吹き払うことで目的とするコート
を行うことができる。Next, as shown in FIG. 2, a rubber sheet is used for a circular portion having an area of の of the end surface area around the center axis of both end surfaces of the honeycomb carrier substrate 1 on which the coating layer is formed. A mask 10 was formed. Then, the openings of the cells in the concentric portions 11 outside the mask 10 were plugged by immersing both ends in a high-boiling point paraffin (wax) molten metal and pulling up. In the case of a metal carrier, the desired coating can be performed by placing the magnet sheet on the end surface of the non-supporting area, pouring the slurry from above, and blowing off excess slurry.
【００２９】そしてマスク１０を除去し、ジニトロジア
ンミン白金硝酸水溶液中に全体を浸漬し、引き上げて余
分な液滴を吹き払った後、乾燥・焼成してＰｔを担持し
た。Ｐｔはマスク１０が除去された目詰めされていない
セルのコート層に担持され、目詰めが形成されているセ
ルはＰｔが担持されていない無担持領域となっている。
なお、目詰めは焼成時に燃焼して除去された。Then, the mask 10 was removed, the whole was immersed in an aqueous solution of dinitrodiammineplatinic nitric acid, pulled up to blow off excess droplets, and then dried and fired to carry Pt. Pt is carried on the coat layer of the cells that have not been clogged, from which the mask 10 has been removed, and the cells that have been clogged are non-carrying regions where Pt is not carried.
Note that the plugging was removed by burning during firing.
【００３０】得られたハニカム触媒では、Ｐｔ担持部分
のＰｔ担持量は２ｇ／Ｌであり、ハニカム触媒全体とし
ては１ｇ／Ｌである。このハニカム触媒を触媒Ａと呼
ぶ。一方、触媒Ａの製造と同様にコート層が形成された
ハニカム担体基材を用意し、マスクや目詰めすることな
くそのままジニトロジアンミン白金硝酸水溶液中に全体
を浸漬し、引き上げて余分な液滴を吹き払った後、乾燥
・焼成してＰｔを担持した。Ｐｔは全体に均一に担持さ
れ、その担持量は１ｇ／Ｌである。このハニカム触媒を
触媒Ｓと呼ぶ。 ＜評価試験＞２４００ｃｃ直列４気筒のディーゼルエン
ジンの排気系に、図１に示すように上流側から下流側へ
向かって触媒Ａ、触媒Ｓ、触媒Ｓの順で直列に３個の触
媒を配置した。そして空間速度６万ｈ-1、触媒Ａへの入
りガス温度６００℃の条件で、１０時間排ガスを流通さ
せる耐久試験を行った。In the obtained honeycomb catalyst, the amount of Pt supported on the Pt-supported portion is 2 g / L, and the total amount of the honeycomb catalyst is 1 g / L. This honeycomb catalyst is called catalyst A. On the other hand, in the same manner as in the production of the catalyst A, a honeycomb carrier base material on which a coat layer is formed is prepared, and the whole is directly immersed in a dinitrodiammineplatinum nitric acid aqueous solution without masking or clogging, and is pulled up to remove extra droplets. After being blown off, it was dried and fired to carry Pt. Pt is uniformly supported on the whole, and the supported amount is 1 g / L. This honeycomb catalyst is called catalyst S. <Evaluation Test> In the exhaust system of a 2400 cc in-line four-cylinder diesel engine, three catalysts were arranged in series in the order of catalyst A, catalyst S, and catalyst S from upstream to downstream as shown in FIG. . Then, an endurance test was conducted in which exhaust gas was circulated for 10 hours under the conditions of a space velocity of 60,000 h -1 and a gas temperature entering the catalyst A of 600 ° C.
【００３１】その後、エンジン回転数を７００〜２００
０ｒｐｍの間で図３に示すように変化させながら、ＮＯ
x 浄化率とＨＣ浄化率を測定した。それぞれの浄化率の
最大値を図４に示す。 （実施例２）実施例１と同様にコート層が形成されたハ
ニカム担体基材を用い、３０×３０ｍｍの市松模様状に
開口が形成されたマスクを両端面に配置した。そして高
沸点パラフィン（ロウ）の溶湯に両端面を漬けて引き上
げることで、セルの開口を市松模様状に目詰めを行っ
た。そして実施例１の触媒Ａと同様にしてＰｔを担持
し、無担持領域をもつハニカム触媒を調製した。Ｐｔ担
持部分のＰｔ担持量は２ｇ／Ｌであり、ハニカム触媒全
体としては１ｇ／Ｌである。このハニカム触媒を触媒Ｂ
と呼ぶ。Thereafter, the engine speed is increased from 700 to 200.
While changing between 0 rpm as shown in FIG.
x The purification rate and the HC purification rate were measured. FIG. 4 shows the maximum value of each purification rate. Example 2 In the same manner as in Example 1, using a honeycomb carrier substrate on which a coat layer was formed, a mask having a checkerboard-shaped opening of 30 × 30 mm was arranged on both end surfaces. Then, both ends were immersed in a high-boiling-point paraffin (wax) molten metal and pulled up to close the cell openings in a checkered pattern. Then, a honeycomb catalyst having Pt supported thereon and having a non-supported region was prepared in the same manner as the catalyst A of Example 1. The Pt carrying amount of the Pt carrying portion is 2 g / L, and the whole honeycomb catalyst is 1 g / L. This honeycomb catalyst was replaced with catalyst B
Call.
【００３２】次に、実施例１と同様のディーゼルエンジ
ンの排気系に、上流側から下流側へ向かって触媒Ｂ、触
媒Ｓ、触媒Ｓの順で直列に３個の触媒を配置した。そし
て実施例１と同様にして耐久試験を行い、同様にＮＯx
浄化率とＨＣ浄化率の最大値を測定した。結果を図４に
示す。 （実施例３）実施例１と同様のハニカム担体基材を用意
し、ハニカム担体基材の両端面の中心軸を中心として面
積が端面面積の１／２の円形部分に、ゴムシートを用い
てマスクを形成した。Next, in the same exhaust system of a diesel engine as in Example 1, three catalysts were arranged in series in the order of catalyst B, catalyst S, and catalyst S from the upstream side to the downstream side. Then, a durability test was performed in the same manner as in Example 1, and NO x was similarly measured.
The maximum values of the purification rate and the HC purification rate were measured. FIG. 4 shows the results. (Example 3) A honeycomb carrier base material similar to that of Example 1 was prepared, and a rubber sheet was used for a circular portion having an area of 1/2 of the end surface area around the center axis of both end surfaces of the honeycomb support base material. A mask was formed.
【００３３】次に実施例１と同様のスラリーに全体を浸
漬し、引き上げて余分なスラリーを吹き払った後、乾燥
・焼成してコート層を形成した。マスクされていた部分
である円形部分から全体の１／２の容積を占める円柱状
部分にはコート層が形成されていない。コート層は、マ
スクされていなかった部分では１００ｇ／Ｌ形成され、
ハニカム担体基材全体では５０ｇ／Ｌ形成されている。Next, the whole was immersed in the same slurry as in Example 1, pulled up to blow off excess slurry, and then dried and fired to form a coat layer. No coat layer is formed on the columnar portion occupying half the volume from the circular portion which is the masked portion. The coat layer is formed at 100 g / L in the unmasked portion,
50 g / L is formed on the entire honeycomb carrier substrate.
【００３４】上記で得られたコート層をもつハニカム担
体基材全体をジニトロジアンミン白金硝酸水溶液中に浸
漬し、引き上げて余分な液滴を吹き払った後、乾燥・焼
成してＰｔを担持した。Ｐｔはコート層に担持され、コ
ート層が形成されていない部分には担持されず無担持領
域となっている。なおＰｔ担持部分のＰｔ担持量は２ｇ
／Ｌであり、ハニカム触媒全体としては１ｇ／Ｌであ
る。このハニカム触媒を触媒Ｃと呼ぶ。The entire honeycomb carrier substrate having a coating layer obtained as described above was immersed in an aqueous solution of dinitrodiammineplatinic nitric acid, pulled up to blow off excess droplets, and dried and fired to carry Pt. Pt is carried on the coat layer, and is not carried on the portion where the coat layer is not formed, and is a non-carried region. The Pt carrying amount of the Pt carrying part is 2 g.
/ L, and 1 g / L for the entire honeycomb catalyst. This honeycomb catalyst is called catalyst C.
【００３５】次に、実施例１と同様のディーゼルエンジ
ンの排気系に、上流側から下流側へ向かって触媒Ｃ、触
媒Ｓ、触媒Ｓの順で直列に３個の触媒を配置した。そし
て実施例１と同様にして耐久試験を行い、同様にＮＯx
浄化率とＨＣ浄化率の最大値を測定した。結果を図４に
示す。 （実施例４）先ず実施例１の触媒Ａと同様にして無担持
領域をもつハニカム触媒を調製した。次に無担持領域の
両端面を同様にしてマスクし、同様にしてＰｔ担持部分
のセル開口の目詰めを行った。Next, in the same exhaust system of the diesel engine as in Example 1, three catalysts were arranged in series in the order of catalyst C, catalyst S, and catalyst S from the upstream side to the downstream side. Then, a durability test was performed in the same manner as in Example 1, and NO x was similarly measured.
The maximum values of the purification rate and the HC purification rate were measured. FIG. 4 shows the results. Example 4 First, a honeycomb catalyst having an unsupported region was prepared in the same manner as in the catalyst A of Example 1. Next, both end surfaces of the non-supporting region were masked in the same manner, and the cell openings of the Pt-supporting portion were similarly plugged.
【００３６】そしてマスクを除去し、異なる濃度のジニ
トロジアンミン白金硝酸水溶液中に全体を浸漬し、引き
上げて余分な液滴を吹き払った後、乾燥・焼成してＰｔ
を担持した。Ｐｔは無担持領域のセルのコート層に担持
された。得られたハニカム触媒では、最初に担持された
Ｐｔ担持部分のＰｔ担持量は２ｇ／Ｌであり、無担持領
域に担持されたＰｔ担持量は０．５ｇ／Ｌであって低担
持領域となっている。このハニカム触媒を触媒Ｄと呼
ぶ。Then, the mask is removed, the whole is immersed in dinitrodiammineplatinum nitric acid aqueous solutions having different concentrations, pulled up to blow off excess droplets, and then dried and fired to form Pt.
Was carried. Pt was supported on the coat layer of the cell in the non-supported area. In the obtained honeycomb catalyst, the supported amount of Pt in the initially supported Pt-supported portion was 2 g / L, and the supported amount of Pt in the non-supported region was 0.5 g / L, which was a low supported region. ing. This honeycomb catalyst is called catalyst D.
【００３７】次に、実施例１と同様のディーゼルエンジ
ンの排気系に、上流側から下流側へ向かって触媒Ｄ、触
媒Ｓ、触媒Ｓの順で直列に３個の触媒を配置した。そし
て実施例１と同様にして耐久試験を行い、同様にＮＯx
浄化率とＨＣ浄化率の最大値を測定した。結果を図４に
示す。 （実施例５）実施例１と同様のディーゼルエンジンの排
気系に、上流側から下流側へ向かって触媒Ｃ、触媒Ｃ、
触媒Ｓの順で直列に３個の触媒を配置した。そして実施
例１と同様にして耐久試験を行い、同様にＮＯx 浄化率
とＨＣ浄化率の最大値を測定した。結果を図４に示す。Next, in the same exhaust system of a diesel engine as in Example 1, three catalysts were arranged in series in the order of catalyst D, catalyst S, and catalyst S from the upstream side to the downstream side. Then, a durability test was performed in the same manner as in Example 1, and NO x was similarly measured.
The maximum values of the purification rate and the HC purification rate were measured. FIG. 4 shows the results. (Embodiment 5) In the same exhaust system of a diesel engine as in Embodiment 1, a catalyst C, a catalyst C,
Three catalysts were arranged in series in the order of catalyst S. Then, a durability test was performed in the same manner as in Example 1, and the maximum values of the NO x purification rate and the HC purification rate were measured in the same manner. FIG. 4 shows the results.
【００３８】（実施例６）実施例１と同様のハニカム担
体基材を用い、両端面の中心軸を中心として面積が端面
面積の２／３の部分に円形のマスクを形成した。次に実
施例１と同様のスラリーに全体を浸漬し、引き上げて余
分なスラリーを吹き払った後、乾燥・焼成してコート層
を形成した。マスクされていた円形部分から軸方向に延
び全体の２／３の容積を占める円柱状部分には、コート
層が形成されていない。コート層は、円柱状部分の外側
の同心円部分に１００ｇ／Ｌ形成されている。(Example 6) Using the same honeycomb carrier base material as in Example 1, a circular mask was formed at a portion whose area was 2/3 of the end face area centered on the center axis of both end faces. Next, the whole was immersed in the same slurry as in Example 1, pulled up to blow off excess slurry, and then dried and fired to form a coat layer. The coat layer is not formed on the columnar portion extending in the axial direction from the masked circular portion and occupying 2/3 of the entire volume. The coat layer is formed in a concentric portion outside the columnar portion at 100 g / L.
【００３９】上記で得られたコート層をもつハニカム担
体基材全体をジニトロジアンミン白金硝酸水溶液中に浸
漬し、引き上げて余分な液滴を吹き払った後、乾燥・焼
成してＰｔを担持した。Ｐｔはコート層に担持され、コ
ート層が形成されていない容積２／３の円柱状部分には
担持されず、その部分が無担持領域となっている。なお
Ｐｔ担持部分のＰｔ担持量は２ｇ／Ｌである。このハニ
カム触媒を触媒Ｅと呼ぶ。The entire honeycomb carrier substrate having the coating layer obtained as described above was immersed in an aqueous solution of dinitrodiammineplatinic nitric acid, pulled up and blown off, and dried and fired to carry Pt. Pt is carried on the coat layer, and is not carried on the cylindrical portion having a volume of 2/3 where the coat layer is not formed, and that portion is a non-carried region. The Pt carrying amount of the Pt carrying portion is 2 g / L. This honeycomb catalyst is called catalyst E.
【００４０】一方、実施例１と同様のハニカム担体基材
を用い、両端面の中心軸を中心として面積が端面面積の
１／３の部分に円形のマスクを形成した。次に実施例１
と同様のスラリーに全体を浸漬し、引き上げて余分なス
ラリーを吹き払った後、乾燥・焼成してコート層を形成
した。マスクされていた円形部分から軸方向に延び全体
の１／３の容積を占める円柱状部分には、コート層が形
成されていない。コート層は、円柱状部分の外側の同心
円部分に１００ｇ／Ｌ形成されている。On the other hand, the same honeycomb carrier base material as in Example 1 was used, and a circular mask was formed at a portion whose area was 1/3 of the end face area centered on the center axis of both end faces. Next, Example 1
The whole was immersed in the same slurry as above, pulled up to blow off excess slurry, and then dried and fired to form a coat layer. The coat layer is not formed on the columnar portion extending in the axial direction from the masked circular portion and occupying one third of the volume. The coat layer is formed in a concentric portion outside the columnar portion at 100 g / L.
【００４１】上記で得られたコート層をもつハニカム担
体基材全体をジニトロジアンミン白金硝酸水溶液中に浸
漬し、引き上げて余分な液滴を吹き払った後、乾燥・焼
成してＰｔを担持した。Ｐｔはコート層に担持され、コ
ート層が形成されていない容積１／３の円柱状部分には
担持されず、その部分が無担持領域となっている。なお
Ｐｔ担持部分のＰｔ担持量は２ｇ／Ｌである。このハニ
カム触媒を触媒Ｆと呼ぶ。The entire honeycomb carrier substrate having the coating layer obtained as described above was immersed in an aqueous solution of dinitrodiammineplatinic nitric acid, pulled up and blown off, and dried and fired to carry Pt. Pt is carried on the coat layer, and is not carried on the columnar portion having a volume of 1/3 where the coat layer is not formed, and that portion is a non-carrying region. The Pt carrying amount of the Pt carrying portion is 2 g / L. This honeycomb catalyst is called catalyst F.
【００４２】そして、実施例１と同様のディーゼルエン
ジンの排気系に、上流側から下流側へ向かって触媒Ｅ、
触媒Ｆ、触媒Ｓの順で直列に３個の触媒を配置した。そ
して実施例１と同様にして耐久試験を行い、同様にＮＯ
x 浄化率とＨＣ浄化率の最大値を測定した。結果を図４
に示す。 （比較例）実施例１と同様のディーゼルエンジンの排気
系に、上流側から下流側へ向かって触媒Ｓ、触媒Ｓ、触
媒Ｓの順で直列に３個の触媒を配置した。そして実施例
１と同様にして耐久試験を行い、同様にＮＯx 浄化率と
ＨＣ浄化率の最大値を測定した。結果を図４に示す。Then, in the same exhaust system of the diesel engine as in the first embodiment, the catalyst E,
Three catalysts were arranged in series in the order of catalyst F and catalyst S. Then, a durability test was performed in the same manner as in Example 1, and NO
The maximum values of x purification rate and HC purification rate were measured. Fig. 4 shows the results.
Shown in (Comparative Example) In the exhaust system of a diesel engine similar to that in Example 1, three catalysts were arranged in series in the order of catalyst S, catalyst S, and catalyst S from upstream to downstream. Then, a durability test was performed in the same manner as in Example 1, and the maximum values of the NO x purification rate and the HC purification rate were measured in the same manner. FIG. 4 shows the results.
【００４３】（評価）図４より、各実施例の触媒装置は
比較例に比べて耐久後にも高いＮＯx 浄化率を示し、Ｈ
Ｃの利用効率が向上していることが明らかである。また
実施例１と実施例２の比較より、無担持部を中心軸部分
に形成する方が好ましいこともわかる。そして実施例１
と実施例４の比較から無担持領域よりもＰｔを僅かに担
持した低担持領域とする方が好ましいことがわかり、実
施例５及び実施例６のように２番目の触媒にも無担持領
域又は低担持領域を設けることが好ましいこともわか
る。(Evaluation) As shown in FIG. 4, the catalyst devices of the respective examples showed a higher NO x purification rate even after the endurance than the comparative example.
It is clear that the utilization efficiency of C has been improved. Further, from a comparison between Example 1 and Example 2, it is understood that it is preferable to form the non-supporting portion on the central shaft portion. And Example 1
From the comparison between Example 4 and Example 4, it was found that it was preferable to set the low-loading area in which Pt was slightly supported rather than the non-loading area. It can also be seen that it is preferable to provide a low carrying area.
【００４４】[0044]
【発明の効果】すなわち請求項１に記載の 排ガス浄化
用触媒装置によれば、ＨＣの利用効率が向上しＮＯx 浄
化能が一層向上する。また請求項２に記載の排ガス浄化
用触媒装置によれば、貴金属担持工程が容易であるため
製造工数が低減され、請求項３に記載の排ガス浄化用触
媒装置によればＨＣの利用効率がさらに向上する。Effects of the Invention] That is, according to the catalytic converter for purifying an exhaust gas according to claim 1, the use efficiency is improved the NO x purification performance of HC is further improved. According to the exhaust gas purifying catalyst device of the second aspect, the noble metal supporting step is easy, so that the number of manufacturing steps is reduced. According to the exhaust gas purifying catalytic device of the third aspect, the utilization efficiency of HC is further improved. improves.
【図１】本発明の一実施例の排ガス浄化用触媒装置の構
成を示す説明図である。FIG. 1 is an explanatory diagram showing a configuration of an exhaust gas purifying catalyst device according to one embodiment of the present invention.
【図２】本発明の一実施例の排ガス浄化用触媒装置にお
ける最上流側の触媒の製造方法を示す説明図である。FIG. 2 is an explanatory diagram showing a method for producing a catalyst on the most upstream side in an exhaust gas purifying catalyst device according to one embodiment of the present invention.
【図３】実施例において浄化率測定に用いたエンジンの
負荷条件を示すタイムチャートである。FIG. 3 is a time chart showing a load condition of an engine used for measurement of a purification rate in an example.
【図４】実施例における最大ＮＯx 浄化率と最大ＨＣ浄
化率を示すグラフである。FIG. 4 is a graph showing a maximum NO x purification rate and a maximum HC purification rate in the example.
ａ：無担持領域 １：ハニカム担体基材
１０：マスクa: Non-supporting area 1: Honeycomb carrier substrate
10: Mask
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｆ０１Ｎ 3/20 Ｂ０１Ｄ 53/36 １０２Ｈ １０３Ｂ ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 6 Identification code FI F01N 3/20 B01D 53/36 102H 103B
Claims (3)
供給して該排ガス中に含まれる窒素酸化物を還元浄化す
るのに用いられ、複数のハニカム触媒を排ガス流れ方向
に対して直列に配置してなる排ガス浄化用触媒装置であ
って、 前記複数のハニカム触媒のうち最下流部に配置されたハ
ニカム触媒を除く少なくとも１個のハニカム触媒の一部
に、貴金属の担持量が少ない低担持領域をハニカム軸方
向に連続して設けたことを特徴とする排ガス浄化用触媒
装置。1. A method for supplying hydrocarbons to an exhaust gas containing excess oxygen to reduce and purify nitrogen oxides contained in the exhaust gas. A plurality of honeycomb catalysts are connected in series in the exhaust gas flow direction. An exhaust gas purifying catalyst device comprising: a plurality of honeycomb catalysts, wherein at least a portion of at least one of the plurality of honeycomb catalysts, excluding a honeycomb catalyst disposed at a most downstream portion, has a low amount of noble metal carried; A catalyst device for purifying exhaust gas, wherein regions are provided continuously in a honeycomb axial direction.
から構成されていることを特徴とする請求項１記載の排
ガス浄化用触媒装置。2. The exhaust gas purifying catalyst device according to claim 1, wherein the low-loading region is formed only of a honeycomb carrier base material.
方向の上流から下流に向かって前記低担持領域が少なく
なっていることを特徴とする請求項１記載の排ガス浄化
用触媒装置。3. The exhaust gas purifying catalyst device according to claim 1, wherein in the plurality of honeycomb catalysts, the low carrying region decreases from upstream to downstream in the exhaust gas flow direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9274297A JPH11107744A (en) | 1997-10-07 | 1997-10-07 | Exhaust emission control catalyst device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9274297A JPH11107744A (en) | 1997-10-07 | 1997-10-07 | Exhaust emission control catalyst device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11107744A true JPH11107744A (en) | 1999-04-20 |
Family
ID=17539692
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9274297A Pending JPH11107744A (en) | 1997-10-07 | 1997-10-07 | Exhaust emission control catalyst device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11107744A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007181752A (en) * | 2006-01-04 | 2007-07-19 | Ne Chemcat Corp | Denitration catalyst composition, integral structure type denitration catalyst and denitrification method using it |
| JP2007521953A (en) * | 2004-02-11 | 2007-08-09 | ユミコア・アクチエンゲゼルシャフト・ウント・コムパニー・コマンディットゲゼルシャフト | Exhaust gas purification catalyst having a noble metal concentration changing in the axial direction, and method for producing the catalyst |
| JP2007330856A (en) * | 2006-06-13 | 2007-12-27 | Ne Chemcat Corp | Denitration catalyst composition, integral denitration catalyst, and denitration method employing the same |
| JP2009273989A (en) * | 2008-05-13 | 2009-11-26 | Toyota Motor Corp | Exhaust gas cleaning device |
| JP2011094514A (en) * | 2009-10-28 | 2011-05-12 | Advantest Corp | Carrier, adhesion amount measuring apparatus, measuring method, program and recording medium |
| JP2013253981A (en) * | 2013-07-05 | 2013-12-19 | Advantest Corp | Adhesion quantity measuring apparatus, measuring method, program, and recording medium |
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1997
- 1997-10-07 JP JP9274297A patent/JPH11107744A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007521953A (en) * | 2004-02-11 | 2007-08-09 | ユミコア・アクチエンゲゼルシャフト・ウント・コムパニー・コマンディットゲゼルシャフト | Exhaust gas purification catalyst having a noble metal concentration changing in the axial direction, and method for producing the catalyst |
| JP2007181752A (en) * | 2006-01-04 | 2007-07-19 | Ne Chemcat Corp | Denitration catalyst composition, integral structure type denitration catalyst and denitrification method using it |
| JP4644605B2 (en) * | 2006-01-04 | 2011-03-02 | エヌ・イーケムキャット株式会社 | Denitration catalyst composition, monolithic structure type denitration catalyst, and denitration method using the same |
| JP2007330856A (en) * | 2006-06-13 | 2007-12-27 | Ne Chemcat Corp | Denitration catalyst composition, integral denitration catalyst, and denitration method employing the same |
| JP4644634B2 (en) * | 2006-06-13 | 2011-03-02 | エヌ・イーケムキャット株式会社 | Denitration catalyst composition, monolithic structure type denitration catalyst, and denitration method using the same |
| JP2009273989A (en) * | 2008-05-13 | 2009-11-26 | Toyota Motor Corp | Exhaust gas cleaning device |
| JP2011094514A (en) * | 2009-10-28 | 2011-05-12 | Advantest Corp | Carrier, adhesion amount measuring apparatus, measuring method, program and recording medium |
| US8969807B2 (en) | 2009-10-28 | 2015-03-03 | Advantest Corporation | Carrier and adhesion amount measuring apparatus, and measuring method, program, and recording medium of the same |
| JP2013253981A (en) * | 2013-07-05 | 2013-12-19 | Advantest Corp | Adhesion quantity measuring apparatus, measuring method, program, and recording medium |
| WO2020054853A1 (en) * | 2018-09-14 | 2020-03-19 | 三菱日立パワーシステムズ株式会社 | Denitrification apparatus |
| CN112638506A (en) * | 2018-09-14 | 2021-04-09 | 三菱动力株式会社 | Denitration device |
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