JP2004195295A

JP2004195295A - Method for manufacturing catalytic structure for exhaust gas cleaning

Info

Publication number: JP2004195295A
Application number: JP2002364056A
Authority: JP
Inventors: Eiji Miyamoto; 英治宮本; Yasuyoshi Kato; 泰良加藤
Original assignee: Babcock Hitachi KK
Current assignee: Mitsubishi Power Ltd
Priority date: 2002-12-16
Filing date: 2002-12-16
Publication date: 2004-07-15

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a catalytic structure for exhaust gas cleaning capable of enhancing a catalytic activity by gas stirring effect and realizing light weight of the catalyst. <P>SOLUTION: In the method for manufacturing the catalytic structure for exhaust gas cleaning, a large number of metal lath base plates 1 formed to a cross section of stairs form, wave form, U-shape or projection/recessed form by providing a large number of band-like projections on a flat plate-like metal lath are laminated to make a carrier structure 3. The carrier structure 3 is immersed in a catalyst component-containing slurry and is carried with the catalyst component so as to fill the network of the metal lath and thereafter, it is dried and calcined. After an optional surface of the metal lath base plate 1 is coated with an oil 5 to form a hydrophobic part and a large number of the metal lath base plates are laminated to make the carrier structure 3. The obtained carrier structure 3 is immersed in the catalyst component-containing slurry and after a through hole part 4 comprising the network of the remained metal lath not carried with the catalyst component is formed on the hydrophobic part, it is dried and calcined. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、排ガス浄化用触媒構造体の製造方法に係り、特に、板状触媒を積層した触媒構造体であって、触媒の軽量化と触媒活性の向上を両立させることができる排ガス浄化用触媒構造体の製造方法に関する。
【０００２】
【従来の技術】
発電所などから排出される排ガス中のＮＯｘは酸性雨などの原因物質であり、その効果的な除去方法として、NH₃を還元剤として選択的接触還元を行う排煙脱硝法が火力発電所を中心に幅広く用いられている。脱硝触媒としては、例えばバナジウム（Ｖ）、モリブデン（Ｍｏ）またはタングステン（Ｗ）を活性成分にした酸化チタン（ＴｉＯ₂）系触媒が好適に使用されている。脱硝触媒は、通常ハニカム状、板状等に成形されるが、その製造方法として、例えば酸化チタンと、Ｖ、Ｍｏ、Ｗなどの触媒活性成分の塩類と水とを共に混練した後、成形、焼成する混練法、酸化チタンの成形−焼成体に触媒活性成分塩類の混合溶液を含浸させる含浸法、金属製またはセラミック製基材を予め調製した触媒成分粉末をスラリ化したものに浸漬して触媒成分をコーティングするコーティング法(特開昭50-128681号公報、特公昭53-34195号公報等) 等が知られている。
【特許文献１】特開昭５５−１３２６４０号公報
【特許文献２】特表２００２−５１３６７１号公報
【０００３】
【発明が解決しようとする課題】
このような触媒製造方法のうち、触媒基材を予め積層して一体化した担体構造体を、触媒成分含有スラリ（以下、単に触媒スラリともいう）に浸漬して触媒成分をコーティングする方法は工数が減少するので、コストを大幅に低減することができる。一方、触媒エレメント相互間に網状物を配置した触媒は、ガス流を乱して反応を促進させることができるので、触媒性能が向上することが分かっている。従って、これら２つの特長を兼ね備えた、高性能かつ低コストな触媒製造方法の開発が望まれていた。
【０００４】
しかしながら、予め触媒エレメントを積層した担体構造体を触媒スラリに浸漬する、コーティング法では、スラリの粘度との関係で、通常、メタルラス基板における網目が全て触媒成分で塞がれるか、または全て開孔状態で残るかの何れかであり、触媒構造体の任意の箇所に貫通孔を設けて必要触媒成分量を低減することによる触媒の軽量化と、前記貫通孔を設けることによるガス攪拌効果に伴う触媒活性の向上とを両立することは困難であるという問題があった。
【０００５】
本発明の課題は、上記従来技術の問題点を解決し、任意の箇所に貫通孔を設けることにより、ガス攪拌効果による触媒活性を向上させるとともに触媒の軽量化を実現することができる排ガス浄化用触媒の製造方法を提供することにある。
【０００６】
【課題を解決するための手段】
上記課題を解決するため、本発明者は、コーティング法を採用した触媒製造方法における、メタルラス基板への触媒成分の担持方法と、得られる触媒構造体の触媒活性および重量との関係等について鋭意研究した結果、メタルラス基板の任意の表面に部分的にあらかじめ油分を塗布、担持させた後、該油分担持メタルラス基板を多数積層して担体構造体とし、得られた担体構造体を触媒スラリに浸漬することにより、前記油分が塗布された疎水性部分に、スラリの表面張力に起因して触媒成分が担持されずに残るメタルラス基板の網目からなる貫通孔が形成されることを見出し、本発明に到達した。
【０００７】
すなわち、本願で特許請求する発明は、以下のとおりである。
（１）平板状のメタルラスに帯状突起を多数設けて断面階段型、波型、コの字型または凹凸型に成形したメタルラス基板を多数積層して担体構造体とし、該担体構造体を触媒成分含有スラリに浸漬して前記メタルラスの網目を埋めるように触媒成分を担持させた後、乾燥、焼成する排ガス浄化用触媒構造体の製造方法において、前記メタルラス基板の任意の表面に油を塗布して疎水性部分を形成したのち多数積層して担体構造体とし、得られた担体構造体を触媒成分含有スラリに浸漬し、前記疎水性部分に、触媒成分が担持されずに残るメタルラスの網目からなる貫通孔を形成させた後、乾燥、焼成することを特徴とする排ガス浄化用触媒構造体の製造方法。
【０００８】
（２）前記疎水性部分を有するメタルラス基板を網状物を介して多数積層して担体構造体を形成することを特徴とする上記（１）に記載の排ガス浄化用触媒構造体の製造方法。
（３）前記担体構造体を、シリカを含有する強化液に浸漬するか、または塗布して強化した後、触媒成分含有スラリに浸漬させることを特徴とする上記（１）または（２）に記載の排ガス浄化用触媒構造体の製造方法。
（４）前記触媒成分が酸化チタンと、バナジウム、モリブデン、タングステンの酸化物のうち少なくとも１種を含有するものであることを特徴とする上記（１）〜（３）の何れかに記載の排ガス浄化用触媒構造体の製造方法。
【０００９】
本発明において、メタルラス基板（以下、メタルラス基材ともいう）の任意の表面に部分的に油分を塗布することにより、その部分が疎水性を有する箇所となる。従って、部分的に油分を塗布したメタルラス基板を多数積層して担体構造体とし、得られた担体構造体を、従来のコーティング法で使用される程度の粘度の触媒スラリ、すなわちメタルラス基材を浸漬することにより基材の網目を全て塞ぐように付着する程度の粘度を有する触媒スラリに浸漬した場合、油分を塗布しない面には触媒成分が網目を塞ぐように付着するが、油分を塗布した疎水性部分には触媒成分が付着しないで網目がそのまま残るようになり、これによって触媒構造体が前記網目からなる貫通孔を有するものとなる。
【００１０】
図２および図３を用いて本発明の原理を説明する。図２は、油分５を部分的に塗布したメタルラス基材１を触媒スラリに浸漬して触媒成分をコーティングする際の前記スラリへの浸漬前後の状態を示す説明図、図３は、油分を全く塗布しないメタルラス基材１を触媒スラリに浸漬して触媒成分をコーティングする際の前記触媒スラリへの浸漬前後の状態を示す説明図である。図２において、油分５を塗布したメタルラス基材１（図中左側）を触媒スラリに浸漬した後引上げると、油分５が塗布されていない部分には触媒成分が付着して目埋め部６が形成されるのに対し、油分５が塗布された疎水性部分には、触媒成分が塗布されることなく残ったメタルラス基板の網目からなる貫通部分４が形成される。一方、油分５が全く塗布、担持されていないメタルラス基材１を触媒スラリに浸漬させた場合は、図３に示したように、全ての網目に触媒成分による目埋め部６が形成されるように触媒成分がコーティングされる。
【００１１】
このように、油分５を塗布した部分と塗布しない部分において触媒成分の担持状態が変化すること、すなわち、油分を塗布させることにより任意の部分に貫通孔を形成することができるので、これを利用して触媒構造体における貫通孔の配置を調整し、触媒面積を損なうことなくガス流攪拌効果を付与して触媒構造体の軽量化と活性向上の両立を実現することができる。
【００１２】
本発明において、メタルラス基材は、ローラ掛け、プレスなどにより圧延されていてもよい。メタルラス基材の断面形状としては、図４（Ａ）〜（Ｄ）に示したような階段型（Ａ）、波型（Ｂ）、コの字型（Ｃ）、凹凸型（Ｄ）などが挙げられる。また、メタルラス基材を多数積層した担体構造体としては、例えば図５（Ａ）〜（Ｄ）に示したような成形済みの触媒基材のみを多数積層して一体化した担体構造体の外、図５（Ｅ）に示したような成形済みの触媒基材と平板状の触媒基材（網状基材）とを交互に積層して一体化したものであってもよい。
【００１３】
本発明において、メタルラス基材に塗布、担持される油分としては、例えば不揮発性、不水溶性の切削油、熱処理油、潤滑油などが挙げられ、触媒スラリに浸漬した場合にもメタルラス基材表面に留まり、基材表面の疎水性を保つものが使用される。油分の動粘度は、例えば１．５ｍｍ²／ｓ（４０℃）以上であることが好ましく、その触媒基材表面への担時量は、触媒基材表面で疎水面を作るのに必要な量であればよく、例えば触媒基材の投影面積当り１．３ｇ／ｍ²以下であることが望ましい。なお、油分の種類は特に限定されるものではなく、上記条件を満たすものであれば、鉱油および／または脂肪油であってもよい。
【００１４】
本発明において、触媒スラリとしては、酸化チタンと、バナジウム、モリブデン、タングステンの酸化物のうち少なくとも１種を含有するものが使用される。触媒スラリには無機繊維を添加させることが好ましい。これによって触媒成分のメタルラス基板への付着強度が向上する。無機繊維としては、例えばＥガラス製繊維が挙げられる。
【００１５】
本発明において、触媒スラリに浸漬する前の担体構造体を強化液に浸漬するかまたは強化液を塗布して強化させることが好ましい。強化液としては、ＳｉＯ₂含有液が好適に使用され、例えば、コロイダルシリカ（日産化学社製、OSゾル、ＳｉＯ₂分20％） 104kg中にＥ硝子製繊維（セントラル硝子社製、ミルドファイバEFH-100、平均長さ100μm)12kgを添加し、攪拌して分散させた後、さらに比表面積95ｍ²／ｇの酸化チタン粉末（石原産業社製、MC90）と比表面積270 ｍ²／ｇの酸化チタン粉末（ミレニアム社製、G5）をそれぞれ45kg添加し、攪拌して得られる強化液が使用される。
【００１６】
なお、本発明において、強化液を使用する場合は、疎水性部分を形成するための油分は、強化液を含浸または塗布し、焼成した後、触媒スラリに浸漬させる直前に、塗布または担持させることが好ましい。強化液適用前に、疎水性部分を形成するための油分を塗布または担持させた場合は、その後、焼成することなく、そのまままたは乾燥後、触媒スラリに浸漬することが好ましい。
【００１７】
【発明の実施の形態】
以下、実施例を用いて本発明を詳細に説明する。
実施例１
メタバナジン酸アンモン306.5gおよび三酸化モリブデン275.9gを2759gの水に混ぜ、約20時間攪拌した後、シリカゾル1432gを混ぜて活性成分溶液を得た。これに、平均長さ100μmの無機繊維製ミルドファイバー1123gおよび酸化チタン2625gを加えて粘度が1800cPの触媒スラリを得た。
一方、SUS430製帯鋼をメタルラス加工した後、400℃で10分間脱脂処理して板厚0.65mm、送りピッチ0.47mm、49目／100mm、目開き幅が約２mmで開孔率74.0％のメタルラスを得た。得られたメタルラスを金型の間に挟み、図４（Ｄ）に示した断面形状で、平坦部からの高さが３ｍｍの帯状突起部を多数形成し、幅498mm、長さ500mmの成形体を得た。
【００１８】
この成形体表面に、動粘度(40℃)1.5ｍｍ²／ｓの不水溶性切削油５を、図６（Ａ）に示すように塗布、担持させて油分担持メタルラス基材とした。このとき油担持量は、担持面積当たり０．７ｇ／ｍ²であった。このメタルラス基材１を多数積層して図５（Ｃ）に示すような担体構造体を得た（油分５図示省略）。
得られた担体構造体を、上記触媒スラリに浸漬した後、120℃で５分間乾燥し、500℃で２時間焼成して図１（Ａ）に示したような、網目の貫通部分４を多数有する触媒構造体を得た。
【００１９】
実施例２
実施例１で用いたメタルラスを金型の間に挟み、図４（Ｄ）に示した断面形状を有し、平坦部からの高さが３ｍｍの帯状突起部をメタルラスの両端方向と30°の角度をつけて多数形成し、幅498mm、長さ500mmの成形体を得た。この成形体表面に、動粘度(40℃)30 ｍｍ²／ｓの熱処理油５を、図６（Ｃ）に示したように、隣接する帯状突起部と対面する位置に塗布、担持させた。このとき油分５の担持量は、担持面積に対して１．０ｇ／ｍ²であった。この成形体を多数積層し、図５（Ａ）に示したような担体構造体を得た（油分５図示省略）。
得られた担体構造体を、実施例１の触媒スラリに浸漬した後、120℃で５分乾燥後、500℃で２時間焼成し、図１（Ｃ）に示した形状の触媒構造体を得た。
【００２０】
実施例３
不水溶性切削油の代わりに、動粘度(100℃)16.5 ｍｍ²／ｓの内燃機関用潤滑油を用いた以外は上記実施例１と同様にして同様の触媒構造体を得た。
実施例４
油分を担持させる状態を、図６（Ｂ）に示したように不規則とした以外は、上記実施例１と同様にして同様の触媒構造体を得た。
【００２１】
比較例１
メタルラス基材に油分を塗布、担持させない以外は、上記実施例１と同様にして同様の触媒構造体を得た。
比較例２
メタルラス基材に油成分を担持させない以外は、上記実施例２と同様にして同様の触媒構造体を得た。
【００２２】
実施例１、実施例３、実施例４および比較例１で得られた触媒構造体について下記表１に示した条件で脱硝活性を測定し、結果を比較例１に対する触媒重量比率とともに表２に示した。また、実施例２および比較例２で得られた触媒構造体について上記と同様の条件で脱硝触媒活性を求め、比較例２に対する触媒重量比率と共に表３に示した。なお、脱硝活性は何れも体積基準総括反応速度定数の比として示した。
【００２３】
【表１】

【００２４】
【表２】

【００２５】
【表３】

【００２６】
表２および表３の結果から、各実施例の触媒構造体は触媒活性が向上し、同時に触媒重量が減少していることが分かる。これは、触媒スラリを付着させることなく残ったラス網目からなる貫通孔が存在することにより触媒重量が減少したことに加え、前記貫通孔の存在により、触媒面積を損なうことなくガス攪拌効果が向上したためと考えられる。また、触媒重量が低減した各実施例においては、必要触媒成分量の減少に伴って、触媒コストが低減した。
本発明の各実施例において、メタルラス基材同士の接触部分にあらかじめ油分を担持させておくことにより、触媒スラリが過剰に付着する、いわゆる液溜まりを防止することができる。
【００２７】
【本発明の効果】
本願の請求項１に記載の発明によれば、触媒構造体の任意の箇所に貫通孔を設けることができるので、ガス流を三次元的に乱して触媒活性を向上させることができるとともに、必要触媒成分量の低減により触媒の軽量化を実現することができる。
本願の請求項２に記載の発明によれば、上記発明の効果に加え、ガス攪拌効果による触媒活性をより向上させることができる。
【００２８】
本願の請求項３に記載の発明によれば、上記発明の効果に加え、触媒強度が著しく向上する。
本願の請求項４に記載の発明によれば、高性能かつ軽量化を実現した脱硝触媒が得られる。
【図面の簡単な説明】
【図１】本発明における触媒構造体の形状の一例を示す説明図。
【図２】本発明の原理を示す説明図。
【図３】従来技術を示す説明図。
【図４】メタルラス基板の断面形状の一例を示す説明図。
【図５】メタルラス基材を積層した担体構造体の一例を示す説明図。
【図６】一部に油分を塗布したメタルラス基材を示す説明図。
【符号の説明】
１…メタルラス基材、３…触媒構造体、４…網目の貫通部分、５…油分、６…触媒成分による目埋め部。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing an exhaust gas purifying catalyst structure, and more particularly to a catalyst structure in which plate-like catalysts are stacked, wherein an exhaust gas purifying catalyst capable of achieving both reduction in the weight of a catalyst and improvement in catalytic activity. The present invention relates to a method for manufacturing a structure.
[0002]
[Prior art]
NOx in exhaust gas emitted from power plants is a causative substance such as acid rain. As an effective method for removing NOx, flue gas denitrification, which performs selective catalytic reduction using NH ₃ as a reducing agent, is used in thermal power plants. Widely used in the center. As the denitration catalyst, for example, a titanium oxide (TiO ₂ ) -based catalyst containing vanadium (V), molybdenum (Mo) or tungsten (W) as an active component is suitably used. The denitration catalyst is usually formed into a honeycomb shape, a plate shape, or the like. As a production method, for example, after kneading together titanium oxide, a salt of a catalytically active component such as V, Mo, W, and water, molding, Kneading method of firing, forming of titanium oxide-impregnation method of impregnating a mixed solution of salts of catalytically active components into a fired body, and immersing a metal or ceramic base material in a slurry of catalyst component powder prepared in advance to form a catalyst. Coating methods for coating components (JP-A-50-128681, JP-B-53-34195, etc.) are known.
[Patent Document 1] JP-A-55-132640 [Patent Document 2] JP-T-2002-513671
[Problems to be solved by the invention]
Among such catalyst production methods, a method of coating a catalyst component by dipping a catalyst structure containing a catalyst base material in advance and integrating the same into a catalyst component-containing slurry (hereinafter, also simply referred to as a catalyst slurry) is a man-hour. , The cost can be greatly reduced. On the other hand, it has been found that a catalyst in which a mesh is arranged between the catalyst elements can disturb the gas flow to promote the reaction, and thus improve the catalytic performance. Therefore, it has been desired to develop a high-performance and low-cost catalyst production method having both these features.
[0004]
However, in the coating method in which the carrier structure in which the catalyst elements are stacked in advance is immersed in the catalyst slurry, the mesh in the metal lath substrate is usually closed with the catalyst component or all the holes are opened due to the viscosity of the slurry. It is either remaining in the state, and is provided with a through hole at an arbitrary position of the catalyst structure to reduce the amount of a necessary catalyst component, and is accompanied by a gas stirring effect by providing the through hole. There is a problem that it is difficult to achieve both improvement of the catalyst activity.
[0005]
An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a through-hole at an arbitrary position, thereby improving the catalytic activity by a gas stirring effect and realizing a lightweight catalyst. It is to provide a method for producing a catalyst.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors have conducted intensive studies on a method for supporting a catalyst component on a metal lath substrate and a relationship between the catalyst activity and the weight of the obtained catalyst structure in a catalyst manufacturing method employing a coating method. As a result, after an oil is partially applied to an arbitrary surface of the metal lath substrate in advance and supported, a large number of the oil-carrying metal lath substrates are stacked to form a support structure, and the obtained support structure is immersed in a catalyst slurry. Through this, the present inventors have found that a through-hole formed of a mesh of a metal lath substrate that remains without supporting a catalyst component due to the surface tension of the slurry is formed in the hydrophobic portion to which the oil is applied, and has reached the present invention. did.
[0007]
That is, the invention claimed in the present application is as follows.
(1) A large number of strip-shaped projections are provided on a flat metal lath, and a large number of metal lath substrates are formed into a step-shaped, corrugated, U-shaped or concave-convex cross section to form a carrier structure, and the carrier structure is used as a catalyst component. After supporting the catalyst component so as to fill the mesh of the metal lath by immersing it in the containing slurry, drying, in the method of manufacturing an exhaust gas purifying catalyst structure to be fired, applying oil to any surface of the metal lath substrate After forming a hydrophobic portion, a large number of layers are laminated to form a carrier structure, and the obtained carrier structure is immersed in a slurry containing a catalyst component, and the hydrophobic portion is composed of a network of metal laths which remain without carrying a catalyst component. A method for producing an exhaust gas purifying catalyst structure, comprising drying and firing after forming a through-hole.
[0008]
(2) The method for producing a catalyst structure for purifying exhaust gas according to the above (1), wherein a large number of metal lath substrates having the hydrophobic portion are laminated via a mesh to form a carrier structure.
(3) The above-mentioned (1) or (2), wherein the carrier structure is immersed in a reinforcing liquid containing silica or coated and reinforced, and then immersed in a catalyst component-containing slurry. Method for producing a catalyst structure for purifying exhaust gas.
(4) The exhaust gas as described in any of (1) to (3) above, wherein the catalyst component contains titanium oxide and at least one of oxides of vanadium, molybdenum, and tungsten. A method for producing a purification catalyst structure.
[0009]
In the present invention, an oil is partially applied to an arbitrary surface of a metal lath substrate (hereinafter, also referred to as a metal lath substrate), so that the portion becomes a hydrophobic portion. Therefore, a large number of metal lath substrates partially coated with oil are laminated to form a support structure, and the obtained support structure is immersed in a catalyst slurry having a viscosity sufficient for use in a conventional coating method, that is, a metal lath base material. When immersed in a catalyst slurry having such a viscosity as to adhere to cover the entire network of the base material, the catalyst component adheres to the surface not coated with the oil so as to close the network, but the oil-coated hydrophobic The network remains as it is without the catalyst component adhering to the active portion, whereby the catalyst structure has a through-hole composed of the network.
[0010]
The principle of the present invention will be described with reference to FIGS. FIG. 2 is an explanatory diagram showing a state before and after immersion in the slurry when the metal lath substrate 1 partially coated with the oil 5 is immersed in the catalyst slurry to coat the catalyst component, and FIG. It is explanatory drawing which shows the state before and after immersion in the said catalyst slurry at the time of immersing the metal lath base material 1 which is not applied in a catalyst slurry, and coating a catalyst component. In FIG. 2, when the metal lath substrate 1 (left side in the figure) coated with the oil 5 is immersed in the catalyst slurry and then pulled up, the catalyst component adheres to the portion where the oil 5 is not coated, and the plugging portion 6 becomes On the other hand, in the hydrophobic portion to which the oil component 5 is applied, the penetrating portion 4 formed of the mesh of the metal lath substrate remaining without the application of the catalyst component is formed. On the other hand, when the metal lath base material 1 on which the oil component 5 is not applied and supported at all is immersed in the catalyst slurry, as shown in FIG. Is coated with a catalyst component.
[0011]
As described above, the carrying state of the catalyst component is changed between the portion where the oil 5 is applied and the portion where the oil 5 is not applied, that is, the through hole can be formed in an arbitrary portion by applying the oil. Thus, the arrangement of the through holes in the catalyst structure can be adjusted, and a gas flow stirring effect can be imparted without impairing the catalyst area, thereby achieving both reduction in the weight of the catalyst structure and improvement in activity.
[0012]
In the present invention, the metal lath base material may be rolled by rolling, pressing, or the like. As the cross-sectional shape of the metal lath base material, a step shape (A), a corrugated shape (B), a U-shaped shape (C), a concavo-convex shape (D), and the like as shown in FIGS. No. Further, as the carrier structure in which a large number of metal lath substrates are laminated, for example, a carrier structure in which only a large number of molded catalyst substrates as shown in FIGS. 5A to 5D are laminated and integrated is used. Alternatively, a molded catalyst substrate and a plate-shaped catalyst substrate (reticulated substrate) as shown in FIG. 5E may be alternately laminated and integrated.
[0013]
In the present invention, examples of the oil component applied and carried on the metal lath substrate include, for example, non-volatile, water-insoluble cutting oil, heat treatment oil, lubricating oil, and the like. And a material that maintains the hydrophobicity of the substrate surface is used. The kinematic viscosity of the oil component is preferably, for example, 1.5 mm ² / s (40 ° C.) or more, and the amount of the oil applied to the surface of the catalyst substrate is the amount required to form a hydrophobic surface on the surface of the catalyst substrate. For example, the density is preferably 1.3 g / m ² or less per projected area of the catalyst substrate. The type of oil component is not particularly limited, and may be a mineral oil and / or a fatty oil as long as the above conditions are satisfied.
[0014]
In the present invention, a catalyst slurry containing titanium oxide and at least one of oxides of vanadium, molybdenum, and tungsten is used. It is preferable to add inorganic fibers to the catalyst slurry. Thereby, the adhesion strength of the catalyst component to the metal lath substrate is improved. Examples of the inorganic fibers include E glass fibers.
[0015]
In the present invention, it is preferable that the carrier structure before immersion in the catalyst slurry is immersed in a strengthening solution or is reinforced by applying a strengthening solution. As the reinforcing liquid, an SiO ₂ -containing liquid is preferably used. For example, E glass fiber (Central Glass, milled fiber EFH) in 104 kg of colloidal silica (manufactured by Nissan Chemical Co., OS sol, SiO ₂ content: 20%) -100, average length 100 [mu] m) 12 kg was added and was dispersed by stirring, further specific surface area 95 m ² / g of titanium oxide powder (Ishihara Sangyo Kaisha Co., MC 90) and the oxidation of specific surface area 270 m ² / g A reinforcing liquid obtained by adding 45 kg of each of titanium powders (G5, manufactured by Millennium) and stirring is used.
[0016]
In the present invention, when using a strengthening liquid, the oil for forming the hydrophobic portion is impregnated or coated with the reinforcing liquid, fired, and then applied or supported immediately before being immersed in the catalyst slurry. Is preferred. When an oil component for forming a hydrophobic portion is applied or supported before the application of the reinforcing liquid, it is preferable to immerse it in a catalyst slurry as it is or after drying without baking.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to examples.
Example 1
306.5 g of ammonium metavanadate and 275.9 g of molybdenum trioxide were mixed in 2759 g of water, stirred for about 20 hours, and then 1432 g of silica sol was mixed to obtain an active ingredient solution. To this, 1123 g of milled fiber made of inorganic fiber having an average length of 100 μm and 2625 g of titanium oxide were added to obtain a catalyst slurry having a viscosity of 1800 cP.
On the other hand, SUS430 strip steel is metal-lathed, then degreased at 400 ° C for 10 minutes, with a sheet thickness of 0.65mm, feed pitch of 0.47mm, 49 stitches / 100mm, opening width of about 2mm and metal lath of 74.0% porosity. Got. The obtained metal lath is sandwiched between molds, and a large number of strip-shaped projections having a cross-sectional shape shown in FIG. 4D and a height of 3 mm from a flat portion are formed, and a molded body having a width of 498 mm and a length of 500 mm is formed. Got.
[0018]
As shown in FIG. 6 (A), a water-insoluble cutting oil 5 having a kinematic viscosity (40 ° C.) of 1.5 mm ² / s was applied and carried on the surface of the molded body as shown in FIG. At this time, the amount of supported oil was 0.7 g / m ² per supported area. By laminating a large number of the metal lath substrates 1, a carrier structure as shown in FIG. 5C was obtained (oil 5 is not shown).
The obtained carrier structure is immersed in the above catalyst slurry, dried at 120 ° C. for 5 minutes, and calcined at 500 ° C. for 2 hours to form a large number of penetrating portions 4 of the mesh as shown in FIG. The resulting catalyst structure was obtained.
[0019]
Example 2
The metal lath used in Example 1 was sandwiched between metal molds, and a band-shaped protrusion having a cross-sectional shape shown in FIG. 4D and having a height of 3 mm from the flat portion was formed at an angle of 30 ° with respect to both ends of the metal lath. A large number of molded articles having a width of 498 mm and a length of 500 mm were obtained at an angle. As shown in FIG. 6 (C), a heat treatment oil 5 having a kinematic viscosity (40 ° C.) of 30 mm ² / s was applied and carried on the surface of the molded body at a position facing the adjacent belt-shaped projection. At this time, the supported amount of the oil component 5 was 1.0 g / m ² with respect to the supported area. A large number of the molded bodies were laminated to obtain a carrier structure as shown in FIG. 5A (oil 5 is not shown).
The obtained carrier structure was immersed in the catalyst slurry of Example 1, dried at 120 ° C. for 5 minutes, and calcined at 500 ° C. for 2 hours to obtain a catalyst structure having the shape shown in FIG. Was.
[0020]
Example 3
A similar catalyst structure was obtained in the same manner as in Example 1 except that a lubricating oil for an internal combustion engine having a kinematic viscosity (100 ° C.) of 16.5 mm ² / s was used instead of the water-insoluble cutting oil.
Example 4
A similar catalyst structure was obtained in the same manner as in Example 1 except that the state in which the oil was carried was made irregular as shown in FIG. 6 (B).
[0021]
Comparative Example 1
A similar catalyst structure was obtained in the same manner as in Example 1 except that no oil was applied to and supported on the metal lath substrate.
Comparative Example 2
A similar catalyst structure was obtained in the same manner as in Example 2 except that the metal component was not carried on the metal lath base material.
[0022]
The denitration activity of the catalyst structures obtained in Example 1, Example 3, Example 4, and Comparative Example 1 was measured under the conditions shown in Table 1 below. The results are shown in Table 2 together with the weight ratio of the catalyst to Comparative Example 1. Indicated. The denitration catalyst activities of the catalyst structures obtained in Example 2 and Comparative Example 2 were determined under the same conditions as described above, and the results are shown in Table 3 together with the catalyst weight ratio to Comparative Example 2. In addition, the denitration activity was shown as a ratio of the volume-based overall reaction rate constant.
[0023]
[Table 1]

[0024]
[Table 2]

[0025]
[Table 3]

[0026]
From the results in Tables 2 and 3, it can be seen that the catalyst structures of the examples have improved catalytic activity and at the same time reduced catalyst weight. This is because, in addition to the presence of the through-hole formed of the lath network remaining without attaching the catalyst slurry, the weight of the catalyst is reduced, and the presence of the through-hole improves the gas stirring effect without impairing the catalyst area. Probably because. Further, in each of the examples in which the weight of the catalyst was reduced, the cost of the catalyst was reduced as the required amount of the catalyst component was reduced.
In each of the embodiments of the present invention, by pre-loading the oil component on the contact portion between the metal lath base materials, it is possible to prevent a so-called liquid pool, in which the catalyst slurry excessively adheres.
[0027]
[Effects of the present invention]
According to the invention as set forth in claim 1 of the present application, a through-hole can be provided at an arbitrary position of the catalyst structure, so that the gas flow can be three-dimensionally disturbed and the catalytic activity can be improved. The reduction in the required amount of the catalyst component makes it possible to reduce the weight of the catalyst.
According to the invention described in claim 2 of the present application, in addition to the effects of the above invention, the catalytic activity by the gas stirring effect can be further improved.
[0028]
According to the invention described in claim 3 of the present application, in addition to the effects of the above invention, the catalyst strength is significantly improved.
According to the invention described in claim 4 of the present application, a denitration catalyst realizing high performance and light weight can be obtained.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an example of the shape of a catalyst structure according to the present invention.
FIG. 2 is an explanatory diagram showing the principle of the present invention.
FIG. 3 is an explanatory diagram showing a conventional technique.
FIG. 4 is an explanatory view showing an example of a cross-sectional shape of a metal lath substrate.
FIG. 5 is an explanatory view showing an example of a carrier structure in which metal lath base materials are laminated.
FIG. 6 is an explanatory view showing a metal lath base material partially coated with an oil component.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Metal lath base material, 3 ... Catalyst structure, 4 ... Penetration part of mesh, 5 ... Oil, 6 ... Filling part by catalyst component.

Claims

A large number of band-shaped projections are provided on a flat metal lath, and a large number of metal lath substrates formed into a step-shaped, corrugated, U-shaped or concave-convex cross section are laminated to form a carrier structure, and the carrier structure is used as a slurry containing a catalyst component. After producing a catalyst structure for purifying an exhaust gas by immersing and carrying a catalyst component so as to fill the mesh of the metal lath, followed by drying and firing, an oil is applied to an arbitrary surface of the metal lath substrate to form a hydrophobic portion. After forming a large number to form a carrier structure, the resulting carrier structure is immersed in a catalyst component-containing slurry, in the hydrophobic portion, a through-hole consisting of a mesh of metal lath remaining without carrying the catalyst component. A method for producing an exhaust gas purifying catalyst structure, comprising forming, drying, and firing.

The method for producing an exhaust gas purifying catalyst structure according to claim 1, wherein a plurality of metal lath substrates having the hydrophobic portion are laminated via a mesh to form a carrier structure.

3. The exhaust gas purifying catalyst structure according to claim 1, wherein the support structure is immersed in a reinforcing liquid containing silica or coated and reinforced to be immersed in a catalyst component-containing slurry. 4. How to make the body.

The exhaust gas purifying catalyst structure according to any one of claims 1 to 3, wherein the catalyst component comprises at least one of oxides of titanium oxide, vanadium, molybdenum, and tungsten. Production method.