JP4234836B2

JP4234836B2 - Honeycomb structure and composite thereof

Info

Publication number: JP4234836B2
Application number: JP04019299A
Authority: JP
Inventors: 義幸笠井; 節原田; 陽人樋口
Original assignee: NGK Insulators Ltd
Current assignee: NGK Insulators Ltd
Priority date: 1999-02-18
Filing date: 1999-02-18
Publication date: 2009-03-04
Anticipated expiration: 2019-02-18
Also published as: JP2000238153A

Description

【０００１】
【発明の属する技術分野】
本発明は、蓄熱体、フィルター、触媒担体等として用いられるハニカム構造体及びその複合体に関する。
【０００２】
【従来の技術】
ハニカム構造体は、図２に示すように、多数のセル２を細孔を備えた隔壁３にて仕切った構造をいう。従って、一端側の複数のセル孔から入ったガスが、ハニカム構造体を通過する際のガスとの接触面積が大きく、ハニカム構造体とガスとの間の熱交換が効率よく行われることとなる。
【０００３】
そのため、自動車排ガスや工場排煙からダストを除くための除塵用フィルター、工場排煙から揮発性有機物質や未燃焼ガスを除くための蓄熱式燃焼装置の蓄熱体、さらには隔壁表面に触媒を担持させることにより自動車排ガス浄化触媒等として、自動車産業、各種製造業等において広範に使用されている。ハニカム構造体には、その用途により、熱による膨張が少ないこと、熱交換特性に優れること等が要求されるため、セラミックス製のものが好適に用いられる。
【０００４】
一方、ハニカム構造体は、自動車排ガス等のように少量のガスを処理する場合は単独で用いられることもあるが、工場排煙等のように大量のガスを処理する場合は、複数のハニカム構造体を、その側面又は端面において接触させた状態で２次元的、３次元的に配置した複合体として使用されることが多い。このような場合において、特に側面において接触させた状態で配置する際には、配置のしやすさという観点より、各セルの断面形状が矩形又は正方形であり、全体としても矩形又は正方形の断面を有するハニカム構造体を用いるのが一般的である。
【０００５】
【発明が解決しようとする課題】
しかしながら、ハニカム構造体には、その成形過程に起因する形状上の歪みが存在する場合があるため、図３（ａ）に示すように、複数のハニカム構造体１を側面において接触させた状態で配置した場合に、各ハニカム構造体１の形状どうしが完全にはフィットしない場合も多い。このような状況では、図３（ｂ）に示すように、ハニカム構造体１どうしがその側面の一部でのみ接触することとなり、その部分に偏荷重が生じてハニカム構造体１が割れることがあるという問題があった。
【０００６】
このような状況を回避するために、ハニカム構造体の外壁の厚さを大きくして機械強度を大きくする手段も考えられるが、外壁の厚さを大きくすると、隔壁部分と外壁との間の熱衝撃による歪みが大きくなるため、ハニカム構造体の耐熱衝撃性が低下するという問題があった。又、ガスは外壁部分を通過できないため、圧力損失が上昇するという問題もあった。
【０００７】
又、ハニカム構造体を単体で用いる場合においても、ハニカム構造体が収納容器からの物理的衝撃により破損しないよう、ハニカム構造体と収納容器との間に緩衝材を挿入していたが、緩衝材を用いるとコスト高になるとともに、緩衝材部分はガスが通過できないため、圧力損失が上昇するという問題があった。
【０００８】
本発明はかかる状況に鑑みてなされたものであり、その目的とするところは、複数のハニカム構造体を側面において接触させた状態で配置しても割れることがないとともに、十分な耐熱衝撃性を有し、かつ圧力損失を上昇させることのないハニカム構造体及びその複合体を提供することにある。
【０００９】
【課題を解決するための手段】
即ち、本発明によれば、各セルの断面形状が矩形又は正方形であり、全体としても矩形又は正方形の断面を有するハニカム構造体であって、上記矩形又は正方形の断面を構成する４辺のうち、少なくとも、全体として矩形又は正方形の断面を有する他のハニカム構造体の側面と接触する辺の辺縁部に位置するセルの水力直径が、他のセルの水力直径よりも小さいハニカム構造体が提供される。
【００１０】
上記のハニカム構造体においては、矩形又は正方形の断面を構成する４辺のすべての辺の辺縁部に位置するセルの水力直径が、他のセルの水力直径よりも小さくてもよい。
【００１１】
上記のハニカム構造体において、上記辺縁部に位置するセルの水力直径は、他のセルの水力直径の１／５以上、４／５以下であることが好ましい。又、外壁の厚さが隔壁の厚さの３倍以下であることが好ましい。又、上記のハニカム構造体は、隔壁表面の少なくとも一部に触媒を塗布したものであってもよい。
【００１２】
又、本発明によれば、上記のハニカム構造体複数を、ハニカム構造体どうしがその側面において接触した状態で配置したハニカム構造体複合体が提供される。上記のハニカム構造体又はハニカム構造体複合体は蓄熱体、フィルター又は触媒担体であってもよい。
【００１３】
【発明の実施の形態】
本発明のハニカム構造体は、図１（ａ）に示すように、各セル２の断面形状が矩形又は正方形であり、全体としても矩形又は正方形の断面を有し、上記矩形又は正方形の断面を構成する４辺のうち、少なくとも１辺の辺縁部に位置するセル２ａの水力直径を、他のセル２ｂの水力直径よりも小さくしている。
【００１４】
セルの機械強度は水力直径が小さい程大きくなるため、そのハニカム構造体の側面に他のハニカム構造体の側面を接触させた状態で配置する場合に、水力直径の小さいセルを設けた側面を上記他のハニカム構造体の側面と接触させれば、ハニカム構造体の形状の歪みにより側面の一部に偏荷重が生じた場合でも、ハニカム構造体が割れるのを防止することができる。又、ガスは上記辺縁部に位置するセルを通過することができるため、圧力損失を上昇させることもなく、又、耐熱衝撃性を低下させることもない。
【００１５】
従って、図１（ｂ）に示すように、ハニカム構造体１の矩形又は正方形の断面を構成する４辺のすべての辺の辺縁部に位置するセル２ａの水力直径を、他のセル２ｂの水力直径よりも小さくすれば、図４に示すように、ハニカム構造体１複数を、それらの側面において接触した状態で配置してハニカム構造体複合体５を形成させる場合においても、圧力損失の上昇や耐熱衝撃性の低下を引き起こすことなく、偏荷重によるハニカム構造体の割れを防止することができる。
【００１６】
又、ハニカム構造体を単体として容器に収納して用いる場合においても、緩衝材を用いる必要がないため、圧力損失の上昇やコストの増大をもたらすことなく、収納容器からの物理的衝撃によるハニカム構造体の破損を防止することができる。
【００１７】
本発明のハニカム構造体において、上記辺縁部に位置するセルの水力直径は、他のセルの水力直径の１／５以上、４／５以下であることが好ましい。上記辺縁部に位置するセルの水力直径が、他のセルの水力直径の１／５未満の場合は、外周壁を厚くした場合と同様に圧力損失が上昇し、４／５を超える場合はハニカム構造体の機械強度を十分に強くすることができないからである。
【００１８】
又、本発明のハニカム構造体において、外壁の厚さは隔壁の厚さの３倍以下であることが好ましい。外壁の厚さが隔壁の厚さの３倍を超える値の場合は、隔壁部分と外壁との間の熱衝撃による歪みが大きくなるため、ハニカム構造体の耐熱衝撃性が低下し、又、圧力損失が上昇するからである。尚、外壁の厚さは隔壁の厚さの２倍以下であることがより好ましい。
【００１９】
本発明のハニカム構造体の材質に特に制限はなく、金属等を用いることもできるが、熱膨張が小さいこと、熱交換特性に優れることから、セラミックスを用いることが好ましい。又、本発明のハニカム構造体の隔壁の厚さ、セルの水力直径、セル数等の値に制限はなく、その用途等に応じて適宜な値を採用することができる。又、本発明のハニカム構造体は矩形又は正方形の断面形状を有するが、本明細書において、「矩形」及び「正方形」の語は、幾何学的な意味においての「矩形」及び「正方形」のみならず、角部を丸める処理を施したものも含まれる。
【００２０】
本発明のハニカム構造体複数を組み合わせることにより、ハニカム構造体複合体とすることができるが、その場合、ハニカム構造体どうしをその側面において接触した状態で、図４（ａ）に示すように１次元的に配置してもよく、図４（ｂ）に示すように２次元的に配置してもよい。又、ハニカム構造体どうしをその端面においても接触した状態で、図４（ｃ）に示すように３次元的に配置してもよい。
【００２１】
本発明のハニカム構造体又はハニカム構造体複合体は、自動車排ガスや工場排煙からダストを除くための除塵用フィルター、工場排煙から揮発性有機物質や未燃焼ガスを除くための蓄熱式燃焼装置の蓄熱体、自動車排ガス浄化触媒、蓄熱触媒脱臭装置等用の触媒担体等として好適に用いることができる。
【００２２】
【実施例】
以下、本発明を図示の実施例を用いてさらに詳しく説明するが、本発明はこれらの実施例に限られるものではない。
【００２３】
（実施例１）
矩形又は正方形の断面を構成する４辺のすべての辺の辺縁部に位置するセル２ａの水力直径を、他のセル２ｂの水力直径よりも小さく設定した図１（ｂ）に示すハニカム構造体１を製造し、その機械強度、耐熱衝撃性及び圧力損失を調べた。
【００２４】
ハニカム構造体１はセラミックから構成し、端面は１５０ｍｍ×１５０ｍｍの正方形とし、長さは５０ｍｍとした。セル２の断面形状は正方形とし、隔壁３の厚さは０．４ｍｍ、外壁４の厚さは１．０ｍｍとした。又、上記辺縁部に位置するセル２ａの水力直径は１．０ｍｍとし、他のセル２ｂの水力直径は２．１ｍｍとした。上記のハニカム構造体１について、下記の方法にて機械強度、耐熱衝撃性及び圧力損失を測定した。
【００２５】
（機械強度の測定方法）ハニカム構造体２個を、側面どうしが当接する状態で配置し、一方のハニカム構造体の側面のうち、他方のハニカム構造体と接触していない側面より荷重を加え、割れが発生した荷重を、両ハニカム構造体が当接する見掛け側面積で割った値を機械強度とした。
【００２６】
（耐熱衝撃性の測定方法）ハニカム構造体を一定温度に加熱した電気炉中に入れ、１時間加熱後、室温に取り出し、目視と打音によりクラックの判定を行い、クラックが無い場合はさらに２５℃高い温度に設定した電気炉に入れ、同じ測定をクラックが発生するまで実施した。５個のハニカム構造体について同様の測定を実施し、クラックが発生した温度の平均値を耐熱衝撃温度とした。
【００２７】
（圧力損失の測定方法）ハニカム構造体の両端面全面が通気する状態とした上で、一方の端面（入口側端面）から４Ｎｍ³／分の流量でガスを送り込み、入口側端面と他方の端面（出口側端面）における差圧を圧力損失とした。尚、上記の流量は、蓄熱燃焼装置におけるハニカム構造体の実際の使用状態を模擬した値であり、流速１ｍ／秒、平均温度４００℃（室温のガスをハニカム構造体に導入し、燃焼室の温度を８００℃とした場合）の条件に相当する。
【００２８】
又、上記のハニカム構造体を図５に示すような蓄熱式燃焼装置１１に設置して脱臭を行い、割れの発生の有無を調べた。但し、ハニカム構造体の寸法は、端面を５００ｍｍ×５００ｍｍの正方形とし、長さを５００ｍｍとした。尚、工場排煙からのＶＯＣ（揮発性有機物質）や未燃焼ガスを除去することを一般に脱臭と称しており、ＶＯＣや未燃焼ガスを含有する脱臭前のガスを未脱臭ガスと呼ぶ。
図５において３塔式蓄熱燃焼装置１１は３塔の熱交換室１２を有し、各熱交換室１２は上部において共通の燃焼室１３に連通している。又、各熱交換室１２は、その下部に各々のガス導入パイプ１４及びガス排出パイプ１５を備える。各熱交換室１２内には蓄熱体１７として上記のハニカム構造体が配置され、燃焼室１３の天井部分にはバーナー１６が設置されている。
【００２９】
このような構成を有する３塔式蓄熱燃焼装置１１において、未脱臭ガスはガス導入パイプ１４を通じて３塔の熱交換室１２のいずれか１塔に導入され、蓄熱体１７を通って燃焼室１３に入る。この際に、未脱臭ガスと蓄熱体１７との熱交換が起こり、未脱臭ガスは燃焼温度近くまで加熱される。燃焼室１３に入った未脱臭ガス中のＶＯＣや未燃焼ガスはバーナー１６によって燃焼し、除去される。脱臭済ガスは他の２塔の熱交換室１２を通り、ガス排出パイプ１５を介して大気中に放出されるが、その際ＶＯＣや未燃焼ガスの燃焼によって生じた燃焼熱は、熱交換室１２内の蓄熱体１７に移行する。未脱臭ガスを導入する熱交換室１２及び脱臭済ガスを排出する熱交換室１２を、一定時間ごとに切り換えて、上記の工程を連続して行うことにより、未脱臭ガスの燃焼で生じた燃焼熱が次の未脱臭ガスの加熱に用いられることとなる。
【００３０】
このような３塔式蓄熱燃焼装置１１を用いて、２分毎に熱交換室１２の切り替えを行いながら、１０００時間の脱臭を行い、脱臭終了後のハニカム構造体の割れの有無を目視にて調べた。尚、熱交換室１２の切り替えはガス導入パイプ１４及びガス排出パイプ１５に設けた弁１０の開閉により行った。又、未脱臭ガスは１０Ｎｍ³／分の流量で導入した。
表１に結果を示す。
【００３１】
（比較例１）辺縁部に水力直径の小さなセルを配置しなかった点を除いては実施例１と同様のハニカム構造体を製造し、その機械強度、耐熱衝撃性及び圧力損失を実施例１同様の方法にて調べた。又、ハニカム構造体を蓄熱燃焼装置に搭載して脱臭を行った場合の割れの発生を、実施例１と同様の方法にて調べた。結果を表１に示す。
【００３２】
（比較例２）
辺縁部に水力直径の小さなセルを配置せずに、厚さ２．０ｍｍの外壁を設けた点を除いては実施例１と同様のハニカム構造体を製造し、その機械強度、耐熱衝撃性及び圧力損失を実施例１同様の方法にて調べた。又、ハニカム構造体を蓄熱燃焼装置に搭載して脱臭を行った場合の割れの発生を、実施例１と同様の方法にて調べた。結果を表１に示す。
【００３３】
【表１】

【００３４】
表１より、実施例１のハニカム構造体においては、圧力損失の上昇は観察されず、又、十分な機械強度及び耐熱衝撃性を有しており、加熱による割れは観察されなかった。一方、比較例１のハニカム構造体には、圧力損失の上昇は観察されなかったが、機械強度が不十分であり、加熱による割れが観察された。又、比較例２のハニカム構造体は、十分な機械強度を有しているが、圧力損失の上昇が見られ、さらに、耐熱衝撃性が不十分なため、加熱による割れが観察された。
【００３５】
【発明の効果】
本発明のハニカム構造体は、側面の一部に偏荷重がかかっても容易に割れることがない。又、十分な耐熱衝撃性を有し、かつ圧力損失を上昇させることもない。そのため、特に、複数のハニカム構造体を側面において接触させた状態で配置して複合体として使用する場合において、ハニカム構造体の破損を効果的に防止でき、従って、自動車排ガスや工場排煙からダストを除くための除塵用フィルター、工場排煙から揮発性有機物質や未燃焼ガスを除くための蓄熱式燃焼装置の蓄熱体、自動車排ガス浄化触媒、蓄熱触媒脱臭装置等用の触媒担体等として好適に用いることができる。
【図面の簡単な説明】
【図１】本発明のハニカム構造体の（ａ）一例及び（ｂ）他の例を示す模式図である。
【図２】ハニカム構造体の一例を示す斜視図である。
【図３】（ａ）及び（ｂ）従来のハニカム構造体の複合体の一例を示す模式図である。
【図４】本発明のハニカム構造体の複合体の（ａ）一例、（ｂ）他の例及び（ｃ）さらに他の例を示す模式図である。
【図５】蓄熱燃焼装置の一例を示す模式図である。
【符号の説明】
１…ハニカム構造体、２…セル、３…隔壁、４…外壁、５…ハニカム構造体複合体、１０…弁、１１…３塔式蓄熱燃焼装置、１２…熱交換室、１３…燃焼室、１４…ガス導入パイプ、１５…ガス排出パイプ、１６…燃焼手段（バーナー）、１７…蓄熱体。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a honeycomb structure used as a heat storage body, a filter, a catalyst carrier and the like and a composite body thereof.
[0002]
[Prior art]
As shown in FIG. 2, the honeycomb structure means a structure in which a large number of cells 2 are partitioned by partition walls 3 having pores. Therefore, the gas entering from the plurality of cell holes on one end side has a large contact area with the gas when passing through the honeycomb structure, and heat exchange between the honeycomb structure and the gas is performed efficiently. .
[0003]
Therefore, a dust removal filter for removing dust from automobile exhaust gas and factory flue gas, a heat storage body of a regenerative combustion device for removing volatile organic substances and unburned gas from factory flue gas, and a catalyst on the partition wall surface As a result, it is widely used as an automobile exhaust gas purification catalyst in the automobile industry, various manufacturing industries, and the like. The honeycomb structure is preferably made of ceramics because it is required to have little expansion due to heat and excellent heat exchange characteristics depending on the application.
[0004]
On the other hand, the honeycomb structure may be used alone when processing a small amount of gas such as automobile exhaust gas, but when processing a large amount of gas such as factory flue gas, a plurality of honeycomb structures are used. It is often used as a composite in which the body is arranged two-dimensionally or three-dimensionally in a state where the body is brought into contact with the side surface or the end surface. In such a case, particularly when placing in contact with the side surface, from the viewpoint of ease of placement, the cross-sectional shape of each cell is rectangular or square, and the cross-section of the rectangle or square as a whole In general, the honeycomb structure is used.
[0005]
[Problems to be solved by the invention]
However, since there may be a distortion in the shape due to the forming process in the honeycomb structure, as shown in FIG. 3A, a plurality of honeycomb structures 1 are in contact with each other on the side surface. In many cases, the shapes of the honeycomb structures 1 do not fit perfectly when arranged. In such a situation, as shown in FIG. 3B, the honeycomb structures 1 are in contact with each other only at a part of the side surface, and an uneven load is generated at the part, and the honeycomb structure 1 may be cracked. There was a problem that there was.
[0006]
In order to avoid such a situation, a means for increasing the mechanical strength by increasing the thickness of the outer wall of the honeycomb structure may be considered. However, if the thickness of the outer wall is increased, the heat between the partition wall portion and the outer wall is increased. There is a problem that the thermal shock resistance of the honeycomb structure is lowered because distortion due to the impact becomes large. Further, since the gas cannot pass through the outer wall portion, there is a problem that the pressure loss increases.
[0007]
In addition, even when the honeycomb structure is used alone, a buffer material is inserted between the honeycomb structure and the storage container so that the honeycomb structure is not damaged by a physical impact from the storage container. When using, there is a problem in that the cost is increased and gas is not allowed to pass through the buffer material portion, resulting in an increase in pressure loss.
[0008]
The present invention has been made in view of such a situation, and the object of the present invention is not to crack even if a plurality of honeycomb structures are arranged in contact with each other on the side surface, and sufficient thermal shock resistance is provided. It is an object of the present invention to provide a honeycomb structure and a composite body thereof that do not increase pressure loss.
[0009]
[Means for Solving the Problems]
That is, according to the present invention, each cell has a rectangular or square cross-sectional shape, and has a rectangular or square cross-section as a whole, out of four sides constituting the rectangular or square cross-section. Provided is a honeycomb structure in which the hydraulic diameter of the cell located at the edge of the side that contacts at least the side surface of the other honeycomb structure having a rectangular or square cross section as a whole is smaller than the hydraulic diameter of the other cell. Is done.
[0010]
In the honeycomb structural body of the upper SL, hydraulic diameter of cells located in the marginal portion of all sides of the four sides constituting a cross-section of rectangular or square, it may be smaller than the hydraulic diameter of the other cells.
[0011]
In the above honeycomb structure, it is preferable that the hydraulic diameter of the cell located at the edge portion is 1/5 or more and 4/5 or less of the hydraulic diameter of the other cells. Moreover, it is preferable that the thickness of an outer wall is 3 times or less of the thickness of a partition. In addition, the honeycomb structure may have a catalyst applied to at least a part of the partition wall surface.
[0012]
In addition, according to the present invention, there is provided a honeycomb structure composite in which a plurality of the honeycomb structures described above are arranged in a state where the honeycomb structures are in contact with each other on the side surface. The honeycomb structure or the honeycomb structure composite may be a heat storage body, a filter, or a catalyst carrier.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In the honeycomb structure of the present invention, as shown in FIG. 1 (a), each cell 2 has a rectangular or square cross-sectional shape, and has a rectangular or square cross-section as a whole. Among the four sides to be configured, the hydraulic diameter of the cell 2a located at the edge of at least one side is made smaller than the hydraulic diameter of the other cell 2b.
[0014]
Since the mechanical strength of the cell increases as the hydraulic diameter decreases, when the side surface of the honeycomb structure is placed in contact with the side surface of another honeycomb structure, the side surface provided with the cell having a small hydraulic diameter is By bringing the honeycomb structure into contact with the side surface of another honeycomb structure, it is possible to prevent the honeycomb structure from cracking even when an uneven load is generated on a part of the side surface due to distortion of the shape of the honeycomb structure. Further, since the gas can pass through the cell located at the edge portion, the pressure loss is not increased and the thermal shock resistance is not lowered.
[0015]
Therefore, as shown in FIG. 1 (b), the hydraulic diameters of the cells 2a located at the edges of all the four sides constituting the rectangular or square cross section of the honeycomb structure 1 are set to be different from those of the other cells 2b. If the diameter is smaller than the hydraulic diameter, as shown in FIG. 4, the pressure loss increases even when a plurality of honeycomb structures 1 are arranged in contact with each other to form the honeycomb structure composite 5. In addition, the honeycomb structure can be prevented from cracking due to an unbalanced load without causing a decrease in thermal shock resistance.
[0016]
Further, even when the honeycomb structure is housed in a container as a single unit, it is not necessary to use a cushioning material, so that the honeycomb structure by physical impact from the storage container does not cause an increase in pressure loss or an increase in cost. Body damage can be prevented.
[0017]
In the honeycomb structure of the present invention, it is preferable that the hydraulic diameter of the cell located at the edge portion is 1/5 or more and 4/5 or less of the hydraulic diameter of other cells. When the hydraulic diameter of the cell located at the edge is less than 1/5 of the hydraulic diameter of other cells, the pressure loss increases in the same manner as when the outer peripheral wall is thickened, and when it exceeds 4/5. This is because the mechanical strength of the honeycomb structure cannot be sufficiently increased.
[0018]
In the honeycomb structure of the present invention, the thickness of the outer wall is preferably not more than three times the thickness of the partition wall. When the thickness of the outer wall is more than three times the thickness of the partition wall, the thermal shock between the partition wall portion and the outer wall increases, resulting in a decrease in the thermal shock resistance of the honeycomb structure. This is because loss increases. In addition, it is more preferable that the thickness of the outer wall is not more than twice the thickness of the partition wall.
[0019]
The material of the honeycomb structure of the present invention is not particularly limited, and a metal or the like can be used. However, ceramic is preferably used because of low thermal expansion and excellent heat exchange characteristics. Moreover, there is no restriction | limiting in values, such as the thickness of the partition of the honeycomb structure of this invention, the hydraulic diameter of a cell, and the number of cells, A suitable value can be employ | adopted according to the use etc. Further, although the honeycomb structure of the present invention has a rectangular or square cross-sectional shape, in this specification, the terms “rectangular” and “square” are only “rectangular” and “square” in a geometric sense. Of course, the thing which performed the process which rounds a corner | angular part is also contained.
[0020]
By combining a plurality of honeycomb structures of the present invention, a honeycomb structure composite can be obtained. In this case, as shown in FIG. 4 (a), the honeycomb structures are in contact with each other on their side surfaces. It may be arranged two-dimensionally or two-dimensionally as shown in FIG. Further, the honeycomb structures may be arranged in a three-dimensional manner as shown in FIG.
[0021]
A honeycomb structure or a honeycomb structure composite of the present invention includes a dust removal filter for removing dust from automobile exhaust gas and factory smoke, and a heat storage combustion apparatus for removing volatile organic substances and unburned gas from factory smoke. It can be suitably used as a catalyst carrier for a heat storage body, an automobile exhaust gas purification catalyst, a heat storage catalyst deodorization device, or the like.
[0022]
【Example】
Hereinafter, the present invention will be described in more detail with reference to the illustrated examples. However, the present invention is not limited to these examples.
[0023]
Example 1
The honeycomb structure shown in FIG. 1 (b) in which the hydraulic diameter of the cell 2a located at the edge of all four sides constituting the rectangular or square cross section is set smaller than the hydraulic diameter of the other cell 2b. 1 was manufactured, and its mechanical strength, thermal shock resistance and pressure loss were examined.
[0024]
The honeycomb structure 1 was made of ceramic, the end face was a 150 mm × 150 mm square, and the length was 50 mm. The cross-sectional shape of the cell 2 was square, the thickness of the partition wall 3 was 0.4 mm, and the thickness of the outer wall 4 was 1.0 mm. Moreover, the hydraulic diameter of the cell 2a located in the said edge part was 1.0 mm, and the hydraulic diameter of the other cell 2b was 2.1 mm. The honeycomb structure 1 was measured for mechanical strength, thermal shock resistance and pressure loss by the following methods.
[0025]
(Measuring method of mechanical strength) Two honeycomb structures are arranged in a state where the side surfaces are in contact with each other, and a load is applied from the side surface of one honeycomb structure which is not in contact with the other honeycomb structure, The value obtained by dividing the load at which cracking occurred by the apparent area where both honeycomb structures abut each other was taken as the mechanical strength.
[0026]
(Measuring method of thermal shock resistance) The honeycomb structure is put in an electric furnace heated to a constant temperature, heated for 1 hour, taken out to room temperature, and checked for cracks by visual observation and hammering sound. The same measurement was carried out until cracking occurred in an electric furnace set at a high temperature. The same measurement was performed on five honeycomb structures, and the average temperature at which cracks occurred was defined as the thermal shock temperature.
[0027]
(Measurement method of pressure loss) After making the whole surface of both ends of the honeycomb structure vent, gas is fed from one end surface (inlet side end surface) at a flow rate of 4 Nm ³ / min. The differential pressure at the (exit side end face) was defined as pressure loss. The above flow rate is a value simulating the actual use state of the honeycomb structure in the heat storage combustion apparatus. The flow rate is 1 m / second, the average temperature is 400 ° C. (room temperature gas is introduced into the honeycomb structure, This corresponds to the condition (when the temperature is 800 ° C.).
[0028]
Further, the above honeycomb structure was installed in a regenerative combustion apparatus 11 as shown in FIG. 5 and deodorized to examine whether cracks occurred. However, the dimensions of the honeycomb structure were a square of 500 mm × 500 mm and a length of 500 mm. Note that removal of VOC (volatile organic substances) and unburned gas from factory flue gas is generally referred to as deodorization, and gas before deodorization containing VOC and unburned gas is referred to as undeodorized gas.
In FIG. 5, a three-column heat storage combustion apparatus 11 has three tower heat exchange chambers 12, and each heat exchange chamber 12 communicates with a common combustion chamber 13 in the upper part. Each heat exchange chamber 12 includes a gas introduction pipe 14 and a gas discharge pipe 15 at the lower part thereof. In each heat exchange chamber 12, the above-described honeycomb structure is disposed as a heat storage body 17, and a burner 16 is installed on the ceiling portion of the combustion chamber 13.
[0029]
In the three-column heat storage combustion apparatus 11 having such a configuration, the non-deodorized gas is introduced into any one of the three heat exchange chambers 12 through the gas introduction pipe 14 and passes through the heat storage body 17 to the combustion chamber 13. enter. At this time, heat exchange between the non-deodorized gas and the heat storage body 17 occurs, and the non-deodorized gas is heated to near the combustion temperature. VOC and unburned gas in the undeodorized gas that has entered the combustion chamber 13 are burned and removed by the burner 16. The deodorized gas passes through the other two towers of heat exchange chambers 12 and is released into the atmosphere via the gas discharge pipe 15. At this time, the combustion heat generated by the combustion of VOC and unburned gas is converted into the heat exchange chamber Transition to the heat storage body 17 in 12. Combustion caused by combustion of undeodorized gas by switching the heat exchange chamber 12 for introducing undeodorized gas and the heat exchange chamber 12 for discharging deodorized gas at regular intervals and performing the above steps continuously. Heat will be used to heat the next undeodorized gas.
[0030]
Using such a three-column heat storage combustion apparatus 11, deodorization is performed for 1000 hours while switching the heat exchange chamber 12 every 2 minutes, and the presence or absence of cracks in the honeycomb structure after deodorization is visually observed. Examined. The heat exchange chamber 12 was switched by opening and closing the valves 10 provided in the gas introduction pipe 14 and the gas discharge pipe 15. Undeodorized gas was introduced at a flow rate of 10 Nm ³ / min.
Table 1 shows the results.
[0031]
(Comparative Example 1) A honeycomb structure similar to that of Example 1 was manufactured except that a cell having a small hydraulic diameter was not disposed at the edge, and the mechanical strength, thermal shock resistance, and pressure loss were measured in Examples. 1 was examined in the same manner. In addition, the occurrence of cracks when the honeycomb structure was mounted on a heat storage combustion apparatus and deodorized was examined by the same method as in Example 1. The results are shown in Table 1.
[0032]
(Comparative Example 2)
A honeycomb structure similar to that of Example 1 was manufactured except that the outer wall having a thickness of 2.0 mm was provided without arranging a cell having a small hydraulic diameter at the edge, and its mechanical strength and thermal shock resistance were produced. The pressure loss was examined in the same manner as in Example 1. In addition, the occurrence of cracks when the honeycomb structure was mounted on a heat storage combustion apparatus and deodorized was examined by the same method as in Example 1. The results are shown in Table 1.
[0033]
[Table 1]

[0034]
From Table 1, in the honeycomb structure of Example 1, an increase in pressure loss was not observed, and sufficient mechanical strength and thermal shock resistance were observed, and cracking due to heating was not observed. On the other hand, in the honeycomb structure of Comparative Example 1, no increase in pressure loss was observed, but the mechanical strength was insufficient and cracks due to heating were observed. Further, although the honeycomb structure of Comparative Example 2 has sufficient mechanical strength, an increase in pressure loss was observed, and further, thermal shock resistance was insufficient, and cracking due to heating was observed.
[0035]
【The invention's effect】
The honeycomb structure of the present invention is not easily cracked even when a partial load is applied to a part of the side surface. Further, it has sufficient thermal shock resistance and does not increase pressure loss. Therefore, in particular, when a plurality of honeycomb structures are arranged in contact with each other and used as a composite, the honeycomb structure can be effectively prevented from being damaged. Suitable as a dust removal filter to remove volatile organic substances, a heat storage body of a regenerative combustion device for removing volatile organic substances and unburned gas from factory smoke, a catalyst carrier for an automobile exhaust gas purification catalyst, a heat storage catalyst deodorization device, etc. Can be used.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing (a) an example and (b) another example of a honeycomb structure of the present invention.
Fig. 2 is a perspective view showing an example of a honeycomb structure.
3A and 3B are schematic views showing an example of a composite body of a conventional honeycomb structure.
Fig. 4 is a schematic diagram showing (a) an example, (b) another example, and (c) yet another example of a composite body of a honeycomb structure of the present invention.
FIG. 5 is a schematic diagram showing an example of a heat storage combustion apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Honeycomb structure, 2 ... Cell, 3 ... Partition wall, 4 ... Outer wall, 5 ... Honeycomb structure composite body, 10 ... Valve, 11 ... Three tower type thermal storage combustion apparatus, 12 ... Heat exchange chamber, 13 ... Combustion chamber, DESCRIPTION OF SYMBOLS 14 ... Gas introduction pipe, 15 ... Gas discharge pipe, 16 ... Combustion means (burner), 17 ... Heat storage body.

Claims

Each cell has a rectangular or square cross-sectional shape, and a honeycomb structure having a rectangular or square cross-section as a whole,
Of the four sides constituting the rectangular or square cross section , at least the hydraulic diameter of the cell located at the edge of the side contacting the side surface of another honeycomb structure having a rectangular or square cross section as a whole is other than A honeycomb structure characterized by being smaller than the hydraulic diameter of the cell.

The honeycomb structure according to claim 1, wherein a hydraulic diameter of a cell located at an edge portion of all four sides constituting the rectangular or square cross section is smaller than a hydraulic diameter of another cell.

The honeycomb structure according to claim 1 or 2, wherein a hydraulic diameter of a cell located at the edge is 1/5 or more and 4/5 or less of a hydraulic diameter of another cell.

The honeycomb structure according to any one of claims 1 to 3, wherein a thickness of the outer wall is three times or less of a thickness of the partition wall.

The honeycomb structure according to any one of claims 1 to 4 , wherein a catalyst is applied to at least a part of the partition wall surface.

A honeycomb structure composite comprising a plurality of the honeycomb structures according to any one of claims 1 to 5 arranged in a state where the honeycomb structures are in contact with each other on a side surface thereof.

The honeycomb structure according to any one of claims 1 to 5 , or the honeycomb structure composite body according to claim 6 , which is a heat storage body, a filter, or a catalyst carrier.