JP2002191987A - Catalyst structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst structure having gas flow channels of opening ratio and free from strain or the like. SOLUTION: In the catalyst structure wherein a large number of plate-shaped catalysts having a catalyst component supported thereon are laminated on a reticulated base material, a rolled metal lath 3, which is obtained by successively introducing a metal latch into the nip between rolling rollers 13 in the same direction as a stretching direction at the time of lathing processing from the end part where lathing processing is started of the metal lath, is used as the reticulated base material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst structure, and more particularly, to a catalyst structure having a high gas passage opening ratio and a small pressure loss.

[0002]

2. Description of the Related Art A catalyst structure is, for example, formed by stacking a large number of plate-like catalysts and storing them in a unit frame. As a plate-like catalyst, for example, a catalyst in which a catalyst component is supported on a mesh base such as an inorganic fiber woven fabric is widely used, and a catalyst using a metal lath as the mesh base is also known.

As described above, a metal lath is used as a net-like base material for the production of a catalyst. For example, a large number of plate-like catalysts having a catalyst component for denitration coated on the surface and opening of the metal lath are stacked and housed in a unit frame. The catalyst structure is used as an exhaust gas treatment device. In such a catalyst structure, it is required that the gas flow path has a large porosity and a small pressure loss, and that the plate-shaped catalyst does not undergo deformation such as distortion due to residual stress. For this reason, attempts have been made to reduce the thickness of a metal lath as a net-like base material by rolling in advance, thereby improving the porosity of the catalyst structure.

[0004]

By the way, a metal lath is manufactured by forming a notch in a metal flat plate with a blade and applying a force to the cut, thereby forming a large number of openings close to a fan shape. For this reason, the metal lath has directionality in all directions, and the shape of the metal lath after rolling varies depending on the direction during rolling. That is, when the metal lath is rolled using the rolling roller, even if the same metal lath and the rolling roller are used, the thickness of the metal lath after rolling varies due to a difference in the introduction direction to the rolling roller,
A rolled metal lath of constant quality could not be obtained, and the catalyst structure using this as a base material was not always satisfactory in terms of porosity and the like. An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a catalyst structure having a large gas passage porosity and no distortion.

[0005]

In order to solve the above-mentioned problems, the present inventor made a notch in a metal flat plate with a blade, for example, in a zigzag pattern, and then stretched the cut portion to form a large number of openings close to a fan shape. As a result of earnestly studying the relationship between the direction of introduction of the metal lath into the rolling roller and the thickness, strength, etc. of the rolled metal lath when the rolled metal lath is introduced into the rolling roller and rolled to a predetermined thickness, lath processing of the metal lath In order from the starting end, the metal lath is rolled in the same direction as the stretching direction at the time of lathing, so that a thin and uniform rolled metal lath can be obtained. And the plate-like catalyst obtained by applying the catalyst component to the rolled metal lath obtained by this method has a simplified lamination method, and the obtained Large gas porosity of the catalyst structure was, found such that there is no such distortion due to residual stress, have reached the present invention.

That is, the invention claimed in the present application is as follows. (1) In a catalyst structure in which a large number of plate-like catalysts in which a catalyst component is supported on a net-like base material are stacked in the same direction as the stretching direction at the time of lathing, in order from the end where lathing is started as the net-like base material. A catalyst structure using a rolled metal lath that has been introduced into a rolling roller and rolled.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 (a) and 1 (b) are explanatory views showing the steps of manufacturing a net-like base material (rolled metal lath) applied to the present invention. In FIG. 1, a notch is formed on a metal flat plate 12 by a lath processing blade 11, and this is
After the metal lath 1 is formed by extending the metal lath 1 in the direction of arrow 2 by 3 and forming the metal lath 1, the metal lath 1 is sequentially arranged in the direction of arrow 2 in FIG. Roller 1 in the same direction as the stretching direction
3 and rolled to produce a rolled metal lath 3.

The obtained rolled metal lath has a small thickness and a uniform thickness, and the distortion due to residual stress during lathing is eliminated. Accordingly, the rolled metal lath is used as a mesh-shaped base material, and a catalyst component is applied thereto to form a plate-shaped catalyst. Thus, a catalyst structure which is high in shape, has small pressure loss, and is stable in shape without causing distortion or the like can be obtained. The reason why the rolled metal lath applied to the present invention has a thin and uniform thickness will be described with reference to FIGS.

FIG. 2 is a diagram showing the shape of the opening of a metal lath which has been lathed. In FIG. 2, a metal plate pulled in the direction of arrow 6 at the time of lath processing has a large number of openings close to a fan shape formed by applying a force to a portion indicated by reference numeral 4, and its cross section is stepwise. Become. As shown in FIG. 3, when the metal lath 1 having such a cross-sectional shape is introduced into the rolling roller 13 in the same direction as the stretching direction at the time of lathing and rolled in order from the end where lathing is started, the rolling roller From 13, a force in the direction indicated by reference numeral 7 is applied to the metal lath 1, and a force for reducing the plate thickness as indicated by reference numeral 8 is applied to the rear portion of the metal lath 1. Therefore, the rolling efficiency is increased, and a rolled metal lath having a thinner and uniform thickness can be obtained.

On the other hand, FIG. 4 is an explanatory view showing a case where rolling is performed by sequentially introducing the roll into the rolling rollers from the direction opposite to the end where lathing is started. In FIG. 4, when the metal lath is rolled by being introduced into the rolling roller 13 in the reverse direction to the stretching direction during lathing (the traveling direction 6 of the metal flat plate during lathing), the metal lath 1 is denoted by reference numeral 7 in the figure. A force for reducing the plate thickness as shown is applied, but when this force is applied, a force acts on the rear portion in a direction to increase the plate thickness as indicated by reference numeral 8 in the figure. Become.
For this reason, the rolling efficiency is reduced and the relative rolling force as a whole is weakened, so that a sufficiently rolled metal lath having a small thickness is not obtained.

On the other hand, the rolling roller 13 is moved in a direction other than the directions shown in FIGS.
Roller 13 and metal lath 1
And the rolling force transmitted from the rolling roller 13 to the metal lath 1 is dispersed.
Therefore, a sufficiently rolled metal lath cannot be obtained. Therefore, in the present invention, a rolled metal lath that has been introduced into a rolling roller and rolled in the same direction as the stretching direction during lathing in order from the end where lathing has begun is used as the net-like base material. In addition, as a rolling method, for example, a method using a press and the like can be mentioned. In the present invention, a method using a rolling roller is applied in order to continuously and efficiently roll the mecarous.

In the present invention, since the front and back of the metal lath during rolling do not affect the shape of the metal lath after rolling, the top and bottom of the front and back of the metal lath when introduced into the rolling roller are not particularly limited. In the present invention, as the catalyst component supported on the rolled metal lath, for example, a material obtained by adding one or more of oxides such as molybdenum, vanadium, and tungsten to titanium oxide as a main component is preferable. Used for The method of supporting the catalyst component is not particularly limited, for example, a method of coating a slurry-like catalyst component on a rolled metal lath,
A known method such as a method of rolling and applying a paste-like catalyst component to a rolled metal lath is employed. FIG. 5 is an explanatory diagram showing an example of a cross-sectional shape of a plate catalyst applied to the present invention. In the figure, a step shape, a corrugated plate shape, a U-shaped cross section and the like are shown. In the present invention, the method for laminating the plate catalyst is not particularly limited.

[0013]

Next, specific examples of the present invention will be described. Example 1 A SUS430 flat plate having a thickness of 0.2 mm was cut with a step width of 0.47.
Lath processing with mm, plate thickness 0.789mm, aperture ratio 53.1%
Got a metal lath. This was introduced into a rolling roller in the direction shown in FIG. 1, that is, in the same direction as the stretching direction during lathing from the lathing start end of the metal lath, and was rolled. Material) was obtained.

Separately, 1.2 kg of titanium oxide having a specific surface area of 270 m ² / g is added to ammonium molybdate ((NH ₄ ) ₆
· And Mo ₇ O ₂₄ · 4H the ₂ O) 0.25 kg, the kneaded to a paste state while adding ammonium metavanadate 0.23 kg, and oxalic 0.3kg and water. To this was added 15 wt% of kaolin-based inorganic fiber (trade name: kao wool), and the mixture was further kneaded to obtain a paste having a water content of 30.5%.

The obtained paste is applied to the opening of the above-mentioned rolled metal lath and the surface of the base material using a pair of rolling rollers, and this is sandwiched between molds so that the cross section shown in FIG. After sintering at 500 ° C for 2 hours, width 4
A catalyst having a thickness of 98 mm, a length of 500 mm and a thickness of 0.66 mm was obtained. When the obtained catalyst body was turned upside down for every other sheet, a large number of the stacked bodies were stacked, and housed in a unit frame to form a catalyst structure.
In addition to being able to be easily laminated, a catalyst structure having a large gas passage porosity and a small pressure loss, and having no deformation due to a strain or the like of the catalyst body was obtained.

Comparative Example 1 A rolled metal lath was obtained in the same manner as in Example 1 except that the direction in which the metal lath was introduced into the rolling roller was rotated 90 degrees from that in Example 1, and a catalyst structure was obtained in the same manner as in Example 1. When the body was formed, the gas flow path porosity did not increase sufficiently, and the plate-like catalyst was found to have a strain that was considered to be caused by residual stress during lath processing of a metal lath as a net-like base material. The thickness of the rolled metal lath at this time was 0.367.
mm.

Comparative Example 2 A rolled metal lath was obtained in the same manner as in Example 1 except that the direction in which the metal lath was introduced into the rolling roller was rotated by 180 degrees from that in Example 1, and a catalyst was obtained in the same manner as in Example 1. When the structure was formed, the gas flow path porosity increased compared to Comparative Example 1, but was not sufficient, and the plate-like catalyst was found to have a strain that was considered to be caused by residual stress during lath processing. . The thickness of the rolled metal lath at this time was 0.1 mm.
It was 324 mm. Table 1 summarizes the production conditions of the rolled metal lath and the obtained substrate thickness in Example 1 and Comparative Examples 1 and 2.

[0018]

[Table 1] From Table 1, it is found that the thickness of the rolled metal lath of Example 1, which was introduced into the rolling roller in the same direction as the stretching direction during lathing and rolled in order from the end where lathing was started, was the thinnest. I understand.

The reason is that the rolling force is dispersed in the comparative example 1 because there are many contact points between the rolling roller and the metal lath, and in the comparative example 2, both ends of the arc where the fan-shaped opening is fixed are deformed. As described above, the force is applied to the center portion of the arc, so that the rolling efficiency is reduced. In contrast,
In the first embodiment, since the center of the arc having a high degree of freedom is deformed by applying a force to both ends of the arc of the fan-shaped opening, the metal lath having the highest rolling efficiency and the thinnest metal lath in all the introduction directions is obtained. It is considered to be obtained. Therefore, the catalyst structure of Example 1 using a rolled metal lath having a uniform thickness and having no distortion due to residual stress or the like as the catalyst substrate has a high gas passage porosity, a small pressure loss, and a low residual pressure. As a result, a stable catalyst structure free of strain or the like due to stress can be obtained.

[0020]

According to the present invention, since a rolled metal lath having a high porosity, which is thin and uniformly rolled in all directions, is used as a catalyst substrate, the pressure loss without deformation such as strain is reduced. Is obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a method for manufacturing a rolled metal lath applied to one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a cross section and a surface of a metal lath.

FIG. 3 is an explanatory diagram showing a force acting on a metal lath during rolling.

FIG. 4 is an explanatory diagram showing a force acting on a metal lath during rolling.

FIG. 5 is an explanatory view showing an example of a cross-sectional shape of a catalyst body applied to the present invention.

[Explanation of symbols]

Reference numeral 1 denotes a metal lath, 2 denotes an arrow indicating a traveling direction to a rolling roller, 3 denotes a rolled metal lath (catalyst base material made of metal lath), 4 denotes a portion where a force is applied during lathing, and 6 denotes a progression of a flat metal plate during lath processing. Arrow indicating direction, 7 ... Arrow indicating direction of force applied from rolling roller to metal lath during rolling,
Arrows indicating the direction of the force applied to the metal lath behind it because the metal lath is deformed by the force of 8 ... 7, 11 ...
Blade for lath processing, 12: metal flat plate, 13: rolling roller.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Yokoyama 3-36 Takara-cho, Kure-shi, Hiroshima Babcock Hitachi Kure Research Laboratory F-term (reference) 3G091 GA02 GA03 GA04 GB02W GB10W 4D048 BA39X BA39Y BB07 BB12 CA06 4G069 AA01 AA11 BB02A BB02B CA03 DA05 EA12 EE06 FB70

Claims (1)

[Claims] 1. In a catalyst structure in which a large number of plate-like catalysts in which a catalyst component is supported on a reticulated base material are arranged in the same order as the stretching direction during the lathing process, in order from the end where lathing is started as the reticulated base material. A catalyst structure characterized by using a rolled metal lath that has been introduced into a rolling roller in a direction and rolled.