JP2006198533A - Diesel exhaust emission treatment apparatus and its manufacturing method - Google Patents

Diesel exhaust emission treatment apparatus and its manufacturing method Download PDF

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JP2006198533A
JP2006198533A JP2005013607A JP2005013607A JP2006198533A JP 2006198533 A JP2006198533 A JP 2006198533A JP 2005013607 A JP2005013607 A JP 2005013607A JP 2005013607 A JP2005013607 A JP 2005013607A JP 2006198533 A JP2006198533 A JP 2006198533A
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porous
corrugated
corrugated plate
plate
exhaust gas
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Satoki Sasaki
郷紀 佐々木
Takeshi Hirota
健 広田
Kazuki Kobayashi
和樹 小林
Hiroshi Ishizaka
浩 石坂
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Mitsubishi Power Ltd
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Babcock Hitachi KK
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a diesel exhaust emission treatment apparatus having a temporal durability, which prevents a filter clogging due to ash dust in an exhaust gas, and its manufacturing method. <P>SOLUTION: An exhaust emission treatment apparatus has a constitution that a pair of a porous flat plate and a porous corrugated plate by which an emission gas purification catalyst is supported are a base unit, a molding laminated such that corrugated plate ridgelines of the porous corrugated plate be orthogonal alternatively is provided, a side surface perpendicular to the corrugated plate ridgelines of the formed body is closed, and an inflow path and an outflow path of each exhaust gas between the porous corrugated plates via the porous flat plate are formed. Then, the apparatus has a porosity in the porous corrugated plate of less than the porosity in the porous flat plate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、排ガス処理装置に係り、特にディーゼルエンジンから排出される排ガス中のばいじん、PM(Particulate Matter、粒子状物質)、NOx(窒素酸化物)を処理する排ガス処理装置およびその製法に関するものである。   The present invention relates to an exhaust gas treatment device, and more particularly to an exhaust gas treatment device for treating dust, PM (Particulate Matter, particulate matter), NOx (nitrogen oxide) in exhaust gas discharged from a diesel engine, and a method for producing the same. is there.

従来、用いられている排ガス処理方法としては、特許文献1に示すように、「ディーゼルエンジンの排気ガス中に存在する粒子を濾過し、そして該粒子をエレメントを通って流れるガスから多孔質壁表面上に捕集するに適する多孔性壁を有する耐高温性フィルターエレメントを有し、」「粒子の燃焼が始まる温度を低下させる白金族金属及びアルカリ土金属酸化物の混合物を含む触媒を該壁の表面上に有する」フィルタを用いる方法が知られている(特許文献1)。   Conventionally, as an exhaust gas treatment method that has been used, as disclosed in Patent Document 1, “the surface of the porous wall is filtered from the gas present in the exhaust gas of the diesel engine and the gas flowing through the element through the particle. Having a high temperature resistant filter element having a porous wall suitable for collection thereon, "a catalyst comprising a mixture of a platinum group metal and an alkaline earth metal oxide that lowers the temperature at which particle combustion begins; A method using a filter having “on the surface” is known (Patent Document 1).

いわゆる燃焼触媒を用いたこの方法は、フィルタに多孔質セラミックスを用いたものであり、炭素などの有機化合物を主成分とするばいじんは多孔質壁面に捕集され、排ガスは該多孔質壁面を通過していく。
通常、炭素の酸化反応は、下記式(1)に従って500℃以上の高温領域で進行するが、ディーゼルエンジンの排ガスは高くても500℃程度、通常は400℃位となるため、他に熱源がなければ、反応に必要な温度に到達しない。
This method using a so-called combustion catalyst uses porous ceramics for the filter, soot and dust mainly containing organic compounds such as carbon are collected on the porous wall surface, and exhaust gas passes through the porous wall surface. I will do it.
Normally, the oxidation reaction of carbon proceeds in the high temperature range of 500 ° C or higher according to the following formula (1), but the exhaust gas of diesel engines is at most about 500 ° C, usually around 400 ° C. Otherwise, the temperature required for the reaction is not reached.

C+O2 → CO2 ・・・・(1)
そこで、上記の白金族金属等を用いた触媒をフィルタに担持することにより、反応温度を350℃程度まで抑え、追加の熱源を要することなく、ばいじんを捕集・燃焼しながら、連続再生運転が可能となる。
C + O 2 → CO 2 (1)
Therefore, by supporting a catalyst using the above platinum group metal or the like on a filter, the reaction temperature is suppressed to about 350 ° C., and an additional heat source is not required, and continuous regeneration operation is performed while collecting and burning dust. It becomes possible.

また特許文献2には、一酸化窒素(NO)含有のディーゼル排ガスを最初に触媒上に通し、NOをNO2に転換させることによりこの二酸化窒素(NO2)がフィルター上に除去された微粒子と反応してこれを燃焼させるディーゼル排ガスの微粒子除去方法が記載されている(特許文献2)。すなわち、酸化触媒をフィルタの上流に配置して、排ガス中のNOをあらかじめNO2に転換しておき、それをフィルタで捕集したばいじんと燃焼反応させるというものである。
さらに特許文献3には、セラミックペーパーを平板及び波板状に加工し、それを交互に積層させて、ハニカム様担体を製造する方法が記載されている。そしてこれらの担体に排ガス処理用の触媒成分を担持した触媒担体が市販されている。
しかし、上記の従来方法では以下の問題点があった。
Also in Patent Document 2, first passed over the catalyst for nitrogen monoxide (NO) containing diesel exhaust, and the fine particles of the nitrogen dioxide by converting NO to NO 2 (NO 2) has been removed on the filter A method for removing particulates from diesel exhaust gas that reacts and burns is described (Patent Document 2). That is, an oxidation catalyst is arranged upstream of the filter, NO in the exhaust gas is converted into NO 2 in advance, and the combustion reaction is performed with the dust collected by the filter.
Further, Patent Document 3 describes a method of manufacturing a honeycomb-like carrier by processing ceramic paper into a flat plate and a corrugated plate and alternately laminating them. Catalyst carriers in which a catalyst component for exhaust gas treatment is supported on these carriers are commercially available.
However, the above conventional method has the following problems.

まず特許文献1の方法では、ディーゼルエンジンから出る排ガス中のばいじんは、フィルタに捕集され、ここでフィルタ2に担持された酸化触媒により、排ガス中のNOが式(2)のように酸化される。   First, in the method of Patent Document 1, the dust in the exhaust gas emitted from the diesel engine is collected by a filter, and the NO in the exhaust gas is oxidized by the oxidation catalyst supported on the filter 2 as shown in the formula (2). The

NO+1/2O2 → NO2 ・・・・(2)
このNO2が、フィルタに捕集されたばいじん(主成分:炭素)と式(3)、(4)に示すような反応を行い、ばいじんを酸化燃焼させる。
C(ばいじん)+2NO2 → CO2+2NO ・・・・(3)
C(ばいじん)+NO2 → CO+NO ・・・・(4)
ところが、通常のエンジンオイルには1〜2重量%程度の金属添加剤に起因する灰分が含まれており、燃料中の硫黄分と反応してCaSO4を主成分とした灰が形成される。この灰は、該酸化触媒面を被覆して触媒活性を低下させることが知られており、特許文献1に示す酸化触媒を担持したセラミックスフィルターは、一定期間以上となると触媒活性が低下し、ばいじんが燃焼されず閉塞してしまう問題があった。
NO + 1 / 2O 2 → NO 2 (2)
This NO 2 reacts with the dust (main component: carbon) collected by the filter as shown in the formulas (3) and (4) to oxidize and burn the dust.
C (dust) + 2NO 2 → CO 2 + 2NO (3)
C (dust) + NO 2 → CO + NO (4)
However, normal engine oil contains about 1 to 2% by weight of ash due to the metal additive, and reacts with sulfur in the fuel to form ash mainly composed of CaSO 4 . This ash is known to cover the oxidation catalyst surface and reduce the catalytic activity. The ceramic filter carrying the oxidation catalyst shown in Patent Document 1 has a reduced catalytic activity when it is over a certain period of time, and soot and dust. There was a problem that would be blocked without burning.

特許文献2の方法でも、酸化触媒はばいじんの多い上流側に配置するため、経時的には酸化触媒の表面に灰が堆積して閉塞し、酸化性能が低下すると考えられる。また、該フィルタにも灰が堆積し、結局はフィルタ圧損を上昇させる。   Even in the method of Patent Document 2, since the oxidation catalyst is arranged on the upstream side with much dust, it is considered that ash accumulates on the surface of the oxidation catalyst and clogs with time, and the oxidation performance is lowered. Also, ash accumulates on the filter, which eventually increases the filter pressure loss.

特許文献3のペーパーハニカムはハニカム状に形成されているため、特にばいじんを捕集するフィルタとして使われることはなく、臭気を分解したり、ばいじんを通過させる途中で燃焼させるなどの効果を狙ったものであり、ばいじんを一旦トラップして燃焼する特許文献1、2に比べて、燃焼・除去効率は低く、10〜40%のばいじんが除去できるのみである。
特公平7-106290号公報 特許第3012249号公報 特開2001−205720号公報
Since the paper honeycomb of Patent Document 3 is formed in a honeycomb shape, it is not particularly used as a filter for collecting dust, and aimed to decompose the odor or burn it while passing the dust. Compared with Patent Documents 1 and 2, in which the dust is once trapped and burned, the combustion / removal efficiency is low, and only 10 to 40% of the dust can be removed.
Japanese Patent Publication No.7-106290 Japanese Patent No. 3012249 Japanese Patent Laid-Open No. 2001-205720

本発明の課題は、上記従来技術の問題点を解決し、排ガス中のばいじんによるフィルタの閉塞を防止した経時耐久性の高いディーゼル排ガスの処理装置およびその製法を提供することにある。   An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a diesel exhaust gas treatment apparatus with high durability over time that prevents the filter from being blocked by dust in the exhaust gas, and a method for producing the same.

上記課題を解決するため、本願で特許請求される発明は以下のとおりである。
(1)排ガス浄化触媒が担持された多孔質波板と多孔質平板の対を基本単位とし、該多孔質波板の波板稜線が交互に直交するように積層された成形体を有し、該成形体の前記波板稜線と直交する側面が閉止され、前記多孔質平板を介して前記多孔質波板との間にそれぞれ排ガスの流入経路と流出経路が形成される排ガス処理装置であって、前記多孔質波板における空隙率を、前記多孔質平板における空隙率よりも小さくしたことを特徴とするディーゼル排ガス処理装置。
(2)前記空隙率を小さくした多孔質波板が、前記排ガス流入経路の多孔質波板であることを特徴とする(1)記載の装置。
(3)前記多孔質波板の空隙率に分布を持たせ、排ガス流入面側の開口部近辺部分の空隙率を小さく、中央部分において空隙率を大きくしたことを特徴とする(1)または(2)記載の装置。
(4)前記多孔質波板および平板には、TiO2、ZrO2、HfO2、SiO2、GeO2、Al2O3およびゼオライトから選ばれた少なくとも1種の触媒担体が担持され、前記波板には、前記平板よりも少量の触媒担体が担持されていることを特徴とする(1)ないし(3)のいずれかに記載の装置。
In order to solve the above problems, the invention claimed in the present application is as follows.
(1) A molded body in which a pair of a porous corrugated plate and a porous flat plate on which an exhaust gas purification catalyst is supported is a basic unit, and the corrugated ridge lines of the porous corrugated plate are alternately stacked, An exhaust gas treatment apparatus in which a side surface perpendicular to the corrugated plate ridge line of the molded body is closed, and an exhaust gas inflow path and an outflow path are formed between the porous flat plate and the porous corrugated sheet, respectively. A diesel exhaust gas treatment apparatus, wherein the porosity of the porous corrugated plate is smaller than the porosity of the porous flat plate.
(2) The apparatus according to (1), wherein the porous corrugated sheet having a reduced porosity is a porous corrugated sheet in the exhaust gas inflow path.
(3) The porosity of the porous corrugated plate is distributed, the porosity in the vicinity of the opening on the exhaust gas inflow surface side is reduced, and the porosity is increased in the central portion (1) or ( 2) The device described.
(4) The porous corrugated plate and the flat plate carry at least one type of catalyst carrier selected from TiO 2 , ZrO 2 , HfO 2 , SiO 2 , GeO 2 , Al 2 O 3 and zeolite, and the wave The apparatus according to any one of (1) to (3), wherein the plate carries a smaller amount of catalyst carrier than the plate.

(5)前記多孔質波板にはTiO2、ZrO2、HfO2、SiO2、GeO2、Al2O3およびゼオライトから選ばれた少なくとも1種の触媒担体が担持され、前記多孔質平板には該触媒担体が担持されていないことを特徴とする(1)ないし(3)のいずれかに記載の装置。
(6)前記多孔質波板には白金族金属を含む触媒成分が担持されていることを特徴とする(1)ないし(5)のいずれかに記載の装置。
(7)前記波板および前記平板がセラミックペーパーからなることを特徴とする(1)ないし(6)のいずれかに記載の装置。
(8)前記多孔質波板を前記多孔質平板よりも長尺のものを用い、前記成形体の開口面から突出すように積層し、前記開口部から突出した波板部分を、触媒担体スラリに浸漬し、該波板に該触媒担体を担持することを特徴とするディーゼル排ガス処理装置の製法。
(5) At least one type of catalyst carrier selected from TiO 2 , ZrO 2 , HfO 2 , SiO 2 , GeO 2 , Al 2 O 3 and zeolite is supported on the porous corrugated plate, The apparatus according to any one of (1) to (3), wherein the catalyst carrier is not supported.
(6) The apparatus according to any one of (1) to (5), wherein a catalyst component containing a platinum group metal is supported on the porous corrugated plate.
(7) The apparatus according to any one of (1) to (6), wherein the corrugated plate and the flat plate are made of ceramic paper.
(8) The porous corrugated plate having a longer length than the porous flat plate is laminated so as to protrude from the opening surface of the molded body, and the corrugated plate portion protruding from the opening is formed into a catalyst carrier slurry. A method for producing a diesel exhaust gas treatment apparatus, wherein the catalyst carrier is supported on the corrugated plate.

本発明に用いる成形体は、特許文献3に示す方法と異なり、図1に示すように波板を最低1枚ごとにその向きが直交するように積層させる。このように積層させたハニカム体を、交差ハニカム体と記す。本交差ハニカム体の波板2のA’面を塞いでガスが流通できないようにし、塞いだ面の対向面Aから排ガスを流通させると、その対向面A’は塞がれているので、ガスは、ガスが流入した波板2や、平板3を貫通したのち、塞がれていない他の2面B、B’及びその対向面から系外に排出される。波板2や、平板3を貫通する際に排ガス中のばいじんを除去することができる。ここで、波板1と波板2の目開きのサイズは、任意とすることができる。     Unlike the method shown in Patent Document 3, the molded body used in the present invention is laminated so that the corrugated plates are at least perpendicular to each other as shown in FIG. The honeycomb body laminated in this way is referred to as a crossed honeycomb body. When the crossing A ′ surface of the corrugated sheet 2 of the crossed honeycomb body is blocked so that the gas cannot flow, and the exhaust gas is flowed from the facing surface A of the plugged surface, the facing surface A ′ is blocked. After passing through the corrugated plate 2 and the flat plate 3 into which the gas has flowed, the other two surfaces B and B ′ that are not blocked and the opposite surfaces are discharged out of the system. Dust in the exhaust gas can be removed when penetrating the corrugated plate 2 or the flat plate 3. Here, the size of the openings of the corrugated sheet 1 and the corrugated sheet 2 can be arbitrary.

波板および平板に担持される触媒担体は、TiO2、ZrO2、HfO2、SiO2、GeO2、Al2O3およびゼオライトから選ばれた少くとも1種で、その上に通常、白金族金属のような酸化触媒が担持される。この酸化触媒により、排ガス中のNOが式(1)の様にNO2に酸化される。 The catalyst support supported on the corrugated plate and the flat plate is at least one selected from TiO 2 , ZrO 2 , HfO 2 , SiO 2 , GeO 2 , Al 2 O 3 and zeolite, and usually a platinum group. An oxidation catalyst such as a metal is supported. By this oxidation catalyst, NO in the exhaust gas is oxidized to NO 2 as shown in formula (1).

NO+1/2O2 → NO2 ・・・・(1)
このNO2が、平板3に捕集されたばいじん(主成分:炭素)と式(2)、(3)に示すような反応を行い、ばいじんを酸化燃焼させる。
C(ばいじん)+2NO2 → CO2+2NO ・・・(2)
C(ばいじん)+NO2 → CO+NO ・・・(3)
堆積したばいじんや燃焼で生じた灰を排出する際には、B、B’面(及びその対向面)を閉鎖するか、A’面のガス流通を開放して、A−A’方向へのガス流通を起こし、ばいじんや灰を排出する。
NO + 1 / 2O 2 → NO 2 ... (1)
This NO 2 reacts with the dust (main component: carbon) collected on the flat plate 3 as shown in the equations (2) and (3) to oxidize and burn the dust.
C (dust) + 2NO 2 → CO 2 + 2NO (2)
C (dust) + NO 2 → CO + NO (3)
When discharging the accumulated dust and ash generated by combustion, close the B and B 'surfaces (and their opposite surfaces) or open the gas flow on the A' surface and move in the AA 'direction. Causes gas circulation and emits dust and ash.

本交差ハニカム体に一様に酸化触媒を担持した場合であっても、かなりの長寿命が期待できるが、本発明によりさらなる長寿命化を図ることができる。
平板3には集塵機能、すなわちガスを貫通させつつ、ばいじんをその表面に濾し取る機能が必要であるが、波板2には特に集塵機能を有する必要はなく、反応(1)によるNO2生成機能を長期にわたり維持する役割がある。
Even when the oxidation catalyst is uniformly supported on the crossed honeycomb body, a considerably long life can be expected. However, the present invention can further extend the life.
The flat plate 3 needs to have a dust collecting function, that is, a function to filter the dust on the surface while allowing gas to pass through. However, the corrugated plate 2 does not need to have a dust collecting function, and NO 2 is generated by the reaction (1). There is a role to maintain the function for a long time.

本発明においては、波板2についてその空隙率をできる限り小さくすることが重要である。具体的には平均〜10μmオーダーの粒径を有するばいじん及び灰が波板2の細孔内に堆積しないようにその細孔を塞いでおくことが重要である。
これは、波板部の細孔サイズが大きい場合には、経時的に未燃ばいじんが堆積し、触媒成分をマスキングしてNO2生成機能が低下する傾向にあり、徐々にばいじん燃焼性能が低下する問題が懸念されるからである。
In the present invention, it is important to make the porosity of the corrugated sheet 2 as small as possible. Specifically, it is important to close the pores so that dust and ash having an average particle size of about 10 μm are not deposited in the pores of the corrugated sheet 2.
This is because, when the corrugated plate has a large pore size, unburned soot accumulates over time, and the catalyst component tends to mask and the NO 2 generation function tends to decline, gradually reducing the soot combustion performance. This is because there is a concern about the problem.

本発明では、少なくとも波板2の細孔を塞ぎ、その空隙率を小さくすることによって、細孔内部へのばいじんのマスキングを防止し、触媒性能の寿命が向上する。
もちろん、波板1の細孔は一様に塞いでもよいが、排ガス出口側の波板の空隙率が小さくなってもあまりメリットはない上、酸化触媒を多く担持してもNO2発生量が増えるだけでかえってデメリットとなることがあるため、排ガス流入面側の空隙率を小さくすることが望ましい。
In the present invention, at least the pores of the corrugated sheet 2 are closed and the porosity is reduced, so that the masking of the dust inside the pores is prevented and the life of the catalyst performance is improved.
Of course, the pores of the corrugated plate 1 may be closed uniformly, but there is not much merit even if the porosity of the corrugated plate on the exhaust gas outlet side is reduced, and even if a large amount of oxidation catalyst is supported, the amount of NO 2 generated is small. It is desirable to reduce the void ratio on the exhaust gas inflow surface side, since it may be disadvantageous just by increasing.

平板3には集塵機能が必要で、細孔を残す必要があるため、上記のようにばいじんが堆積し、触媒を担持してもマスキングして性能が低下する問題は残るが、波板側の触媒性能(NO2生成機能)を高めておけば、上記(3)の反応により、NO2生成能は長時間維持され、安定に長時間ばいじんを燃焼することが可能となる。 Since the flat plate 3 needs a dust collecting function and needs to leave pores, soot and dust accumulate as described above, and there remains a problem that the performance is deteriorated by masking even if the catalyst is supported. If the catalyst performance (NO 2 generation function) is increased, the NO 2 generation ability is maintained for a long time by the reaction of (3) above, and it becomes possible to stably burn soot for a long time.

本発明の効果をまとめると以下のとおりである。
(1)少なくともガス流入口側の波板の空隙率を小さくすることによって、運転負荷の一時的な低下により低温となった場合等に、該波板に未焼却のままばいじんが堆積することが防止でき、少なくとも波板に担持された酸化触媒の性能低下を防止できる。かつ該ばいじんや灰を除去することが容易になり、寿命が向上する。
(2)一方、平板はフィルタ機能を有する必要があり、空隙率をあまり小さくすることは望ましくない。したがってそのままでは、低温時にばいじんの堆積の可能性があるが、本発明では波板部の触媒性能が低下しないので、前記(3)、(4)式のNO2による酸化燃焼反応が十分進行するため、ばいじんの堆積は起こらない。
(3)本発明では、多孔質のセラミックペーパーをフィルタ担体とすることによって微細ばいじんを除去することが可能である。
以下、実施例に基づいて本発明を説明する。
The effects of the present invention are summarized as follows.
(1) By reducing the porosity of the corrugated plate on the gas inlet side at least, soot can be deposited on the corrugated plate unburned when the operating load becomes low due to a temporary decrease in operating load. It is possible to prevent the deterioration of the performance of the oxidation catalyst supported on the corrugated plate. Moreover, it becomes easy to remove the dust and ash, and the life is improved.
(2) On the other hand, the flat plate needs to have a filter function, and it is not desirable to make the porosity too small. Therefore, as it is, there is a possibility of soot accumulation at low temperatures, but in the present invention, the catalytic performance of the corrugated plate portion does not deteriorate, so the oxidative combustion reaction with NO 2 in the above formulas (3) and (4) proceeds sufficiently. Therefore, dust accumulation does not occur.
(3) In the present invention, fine dust can be removed by using porous ceramic paper as a filter carrier.
Hereinafter, the present invention will be described based on examples.

図1は、本発明の実施例に基づくディーゼル排ガス処理用の交差ハニカム体を示す図面である。
この交差ハニカム体は、それぞれ多孔質体(セラミックペーパー)からなる平板3、波板1、平板3、波板2、平板3および波板1の順に積層されて形成されているが、波板2の開口面は、波板1の開口面と直交するように積層されている。この交差ハニカム体には、TiO2スラリを触媒担体として担持した後、触媒成分として白金を含浸したものを用いている。ばいじんを含む排ガスは、例えば波板2の開口面Aから流入されるが、その対向面A’を、図示しないバルブ等で閉塞してガスが流通しないようにすれば、排ガスは波板2に接合された多孔質平板3を点線のように貫通して波板1と多孔質平板3の間の開口面B、B’および図示しないその対向面から排出される。平板3を貫通する時に、排ガス中のばいじんはその平板3の面上で捕集されるが、捕集されたばいじんは、波板2、平板3に担持した酸化触媒により、燃焼される。本発明では、波板2の空隙率が平板3に比べて小さくなっているため、波板2の表面には一部のばいじんが付着してもその内部には堆積できず、ばいじんによる波板2の酸化機能の低下が防止される。
FIG. 1 is a drawing showing a cross honeycomb body for diesel exhaust gas treatment according to an embodiment of the present invention.
The cross honeycomb body is formed by laminating a flat plate 3, a corrugated plate 1, a flat plate 3, a corrugated plate 2, a flat plate 3 and a corrugated plate 1, each of which is made of a porous body (ceramic paper). Are laminated so as to be orthogonal to the opening surface of the corrugated plate 1. This cross honeycomb body uses a TiO 2 slurry supported as a catalyst carrier and then impregnated with platinum as a catalyst component. The exhaust gas containing soot and dust is introduced, for example, from the opening surface A of the corrugated plate 2. If the opposing surface A ′ is blocked by a valve or the like (not shown) so that the gas does not flow, the exhaust gas enters the corrugated plate 2. It penetrates the joined porous flat plate 3 as shown by a dotted line, and is discharged from the opening surfaces B and B ′ between the corrugated plate 1 and the porous flat plate 3 and its opposite surface (not shown). When passing through the flat plate 3, the dust in the exhaust gas is collected on the surface of the flat plate 3, but the collected dust is burned by the corrugated plate 2 and the oxidation catalyst supported on the flat plate 3. In the present invention, since the porosity of the corrugated plate 2 is smaller than that of the flat plate 3, even if a part of the dust adheres to the surface of the corrugated plate 2, it cannot be deposited inside the corrugated plate 2. 2 is prevented from lowering the oxidation function.

図2は、本発明の交差ハニカム体を作製する工程を示す説明図である。ガス流入部に当たる波板2は、多孔質板を変形させ波板状に加工した後、細孔径0.01〜10μmに合致する粒子を含む高濃度(1〜50重量%)TiO2スラリに浸漬してTiO2粒子を担持させた。一方、波板1および平板3には低濃度(1〜40重量%)TiO2スラリに浸漬してTiO2粒子を担持させた。波板2a、波板1a、平板3aにそれぞれ触媒成分として白金を含浸させた後、積層して交差ハニカム体を作製した。 FIG. 2 is an explanatory view showing a process for producing a cross honeycomb body of the present invention. The corrugated plate 2 corresponding to the gas inflow portion is deformed into a corrugated plate by deforming the porous plate, and then immersed in a high concentration (1 to 50% by weight) TiO 2 slurry containing particles having a pore diameter of 0.01 to 10 μm. TiO 2 particles were supported. On the other hand, the corrugated plate 1 and the flat plate 3 were immersed in a low concentration (1 to 40% by weight) TiO 2 slurry to carry TiO 2 particles. The corrugated plate 2a, the corrugated plate 1a, and the flat plate 3a were impregnated with platinum as a catalyst component, and then laminated to produce a crossed honeycomb body.

図3は、本発明の交差ハニカム体の他の作製例を示す説明図である。
本実施例では、図2とは異なり、交差ハニカム体を先に作製し、触媒担体を後から担持させる方法を採用した。具体的には、まず交差ハニカム体に図2の実施例で用いた低濃度TiO2スラリを開口部から流入させて交差ハニカム体全体に担持し、乾燥した。その後、ガス入口面から見て波板2が水平となるように置き、かつ、ガス入口面から図2の実施例で用いた高濃度TiO2スラリを、ガス入口側となる波板2の開口部から流入させて波板2のみに浸漬させ乾燥した。なお、高濃度TiO2スラリは、波板2全体に含浸させる必要はなく、ガス入口面側の約1/2〜1/3部分を含浸できるだけでも本発明の効果が得られる。
FIG. 3 is an explanatory view showing another example of production of the intersecting honeycomb body of the present invention.
In the present embodiment, unlike FIG. 2, a method in which a cross honeycomb body is first produced and a catalyst carrier is carried later is employed. Specifically, first, the low-concentration TiO 2 slurry used in the embodiment of FIG. 2 was introduced into the crossed honeycomb body from the opening, supported on the entire crossed honeycomb body, and dried. Thereafter, the corrugated plate 2 is placed so as to be horizontal when viewed from the gas inlet surface, and the high concentration TiO 2 slurry used in the embodiment of FIG. 2 is opened from the gas inlet surface to the corrugated plate 2 on the gas inlet side. It was made to flow from the part and dipped only in the corrugated sheet 2 and dried. The high concentration TiO 2 slurry does not need to be impregnated in the entire corrugated plate 2, and the effect of the present invention can be obtained only by impregnating about 1/2 to 1/3 portion on the gas inlet surface side.

図4は、本発明の交差ハニカム体のさらに他の作製例を示す説明図である。本実施例では、波板2として、平板3よりも長尺のものを用い、ガス入口開口面から突出させるようにして積層し、開口部から突出した波板の突出部に、高濃度TiO2スラリを浸漬し、波板2のみに高濃度TiO2スラリを担持させた。波板の突出部のみ浸漬させた場合においても、セラミックペーパーの吸水性を利用して、必要量のTiO2スラリを吸い上げ、担持させることができる。波板の突出部(浸漬部)は、そのまま触媒成分を担持させて酸化触媒機能を持たせた方が、ばいじん等の内部堆積を抑えることができ、また、触媒面が増えてNO2生成量が増えるため、ばいじんの燃焼効率を高く保つことができ、望ましい。 FIG. 4 is an explanatory view showing still another example of manufacturing the cross honeycomb body of the present invention. In this embodiment, the corrugated plate 2 is longer than the flat plate 3 and is laminated so as to protrude from the gas inlet opening surface, and the corrugated plate protruding from the opening has a high concentration of TiO 2. The slurry was immersed, and only the corrugated sheet 2 was loaded with a high concentration TiO 2 slurry. Even when only the protruding portion of the corrugated sheet is immersed, the required amount of TiO 2 slurry can be sucked and supported by utilizing the water absorption of the ceramic paper. The corrugated protrusion (immersion part) can support the oxidation catalyst function by supporting the catalyst component as it is, and can suppress the internal accumulation of dust and the like, and the catalyst surface increases and the amount of NO 2 generated Therefore, the combustion efficiency of soot and dust can be kept high, which is desirable.

[比較例]
交差ハニカム体に低濃度TiO2スラリを担持し、触媒成分として白金を含浸したものを用いた。
以上の実施例、比較例による経時的なNO2生成量を調べたところ、以下の表1のような結果が得られた。
[Comparative example]
A cross-honeycomb body carrying a low concentration TiO 2 slurry and impregnated with platinum as a catalyst component was used.
When the amount of NO2 produced over time in the above Examples and Comparative Examples was examined, the results shown in Table 1 below were obtained.

Figure 2006198533
Figure 2006198533

実施例1、3の耐久性は比較例よりかなり高く、4000h以上でも十分使用可能な性能を維持することができた。   The durability of Examples 1 and 3 was considerably higher than that of the comparative example, and the performance that was sufficiently usable could be maintained even after 4000 hours.

本発明の実施例1のハニカム交差体を示す説明図。BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the honeycomb crossing body of Example 1 of this invention. 本発明の実施例1のハニカム体の製造工程を示す説明図。Explanatory drawing which shows the manufacturing process of the honeycomb body of Example 1 of this invention. 本発明の実施例2のハニカム体の製造工程を示す説明図。Explanatory drawing which shows the manufacturing process of the honeycomb body of Example 2 of this invention. 本発明の実施例3のハニカム体の製造工程を示す説明図。Explanatory drawing which shows the manufacturing process of the honeycomb body of Example 3 of this invention.

Claims (8)

排ガス浄化触媒が担持された多孔質波板と多孔質平板の対を基本単位とし、該多孔質波板の波板稜線が交互に直交するように積層された成形体を有し、該成形体の前記波板稜線と直交する側面が閉止され、前記多孔質平板を介して前記多孔質波板との間にそれぞれ排ガスの流入経路と流出経路が形成される排ガス処理装置であって、前記多孔質波板における空隙率を、前記多孔質平板における空隙率よりも小さくしたことを特徴とするディーゼル排ガス処理装置。 A molded body in which a pair of a porous corrugated sheet and a porous flat plate carrying an exhaust gas purification catalyst is a basic unit, and the corrugated ridgelines of the porous corrugated sheet are alternately orthogonally crossed, An exhaust gas treatment apparatus in which a side surface perpendicular to the corrugated plate ridge line is closed and an exhaust gas inflow path and an outflow path are formed between the porous corrugated plate and the porous corrugated sheet through the porous flat plate, respectively, A diesel exhaust gas treatment apparatus, wherein a porosity of a corrugated plate is smaller than a porosity of the porous flat plate. 前記空隙率を小さくした多孔質波板が、前記排ガス流入経路の多孔質波板であることを特徴とする請求項1記載の装置。 The apparatus according to claim 1, wherein the porous corrugated sheet having a reduced porosity is the porous corrugated sheet in the exhaust gas inflow path. 前記多孔質波板の空隙率に分布を持たせ、排ガス流入面側の開口部近辺部分の空隙率を小さく、中央部分において空隙率を大きくしたことを特徴とする請求項1または2記載の装置。 3. The apparatus according to claim 1, wherein the porosity of the porous corrugated plate is distributed, the porosity in the vicinity of the opening on the exhaust gas inflow surface side is reduced, and the porosity is increased in the central portion. . 前記多孔質波板および平板には、TiO2、ZrO2、HfO2、SiO2、GeO2、Al2O3およびゼオライトから選ばれた少なくとも1種の触媒担体が担持され、前記波板には、前記平板よりも少量の触媒担体が担持されていることを特徴とする請求項1ないし3のいずれかに記載の装置。 The porous corrugated plate and flat plate carry at least one catalyst carrier selected from TiO 2 , ZrO 2 , HfO 2 , SiO 2 , GeO 2 , Al 2 O 3 and zeolite, and the corrugated plate has 4. The apparatus according to claim 1, wherein a smaller amount of catalyst carrier is supported than the flat plate. 前記多孔質波板にはTiO2、ZrO2、HfO2、SiO2、GeO2、Al2O3およびゼオライトから選ばれた少なくとも1種の触媒担体が担持され、前記多孔質平板には該触媒担体が担持されていないことを特徴とする請求項1ないし3のいずれかに記載の装置。 The porous corrugated plate carries at least one catalyst carrier selected from TiO 2 , ZrO 2 , HfO 2 , SiO 2 , GeO 2 , Al 2 O 3 and zeolite, and the porous flat plate supports the catalyst. 4. The device according to claim 1, wherein no carrier is supported. 前記多孔質波板には白金族金属を含む触媒成分が担持されていることを特徴とする請求項1ないし5のいずれかに記載の装置。 6. The apparatus according to claim 1, wherein a catalyst component containing a platinum group metal is supported on the porous corrugated plate. 前記波板および前記平板がセラミックペーパーからなることを特徴とするる請求項1ないし6のいずれかに記載の装置。 7. The apparatus according to claim 1, wherein the corrugated plate and the flat plate are made of ceramic paper. 前記多孔質波板を前記多孔質平板よりも長尺のものを用い、前記成形体の開口面から突出すように積層し、前記開口部から突出した波板部分を、触媒担体スラリに浸漬し、該波板に該触媒担体を担持することを特徴とするディーゼル排ガス処理装置の製法。
The porous corrugated plate is longer than the porous flat plate, laminated so as to protrude from the opening surface of the molded body, and the corrugated plate portion protruding from the opening is immersed in a catalyst carrier slurry. A method for producing a diesel exhaust gas treatment apparatus, wherein the catalyst carrier is supported on the corrugated plate.
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WO2022210469A1 (en) 2021-03-31 2022-10-06 三菱重工業株式会社 Temperature uniformized heat-exchange-type catalyst reactor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022210469A1 (en) 2021-03-31 2022-10-06 三菱重工業株式会社 Temperature uniformized heat-exchange-type catalyst reactor

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