JP5863371B2 - Catalyst structure - Google Patents

Description

  The present invention relates to a plate-like catalyst structure for purifying harmful substances contained in exhaust gas, and more particularly to a plate-like catalyst structure for exhaust gas treatment.

The catalyst for purifying the harmful substances contained in the exhaust gas has various shapes such as a plate shape, honeycomb shape, granular shape, cylindrical shape, and pellet shape. The present invention relates to a plate-like catalyst structure housed in a (frame).
In general, when dust is contained in a gas such as a coal fired boiler, the clogging or wear of the catalyst due to the dust becomes a problem. However, the plate-like catalyst structure includes a flat catalyst element 10 as a unit (as shown in FIG. (Frame body) 4 has the advantage that it is more resistant to end wear than other shapes, has excellent durability against clogging and wear, and has lower pressure loss than other shapes due to its laminated structure within 4. Have. Further, in the case of a shape other than a plate shape, since the substrate and the carrier are not included inside, the strength of the catalyst itself must be maintained high, whereas the reaction efficiency of the catalyst may be sacrificed, In the case of a plate-like catalyst, the strength can be maintained by the substrate, and the catalyst component also has an advantage that the composition can maximize the reaction efficiency.
As a conventional plate-shaped catalyst structure, one having a cross-sectional shape as shown in FIGS. 10 (a) and 10 (b) in which an element 10 having a flat plate portion 1 and a crest portion 2 as shown in FIG. 7 is laminated is known. Yes. In the figure, 3 is an element support part at the end of the catalyst unit (Patent Documents 1 and 2).

Japanese Patent Publication No.58-50137 Japanese Patent Laid-Open No. 11-347422

In the conventional catalyst structure shown in FIGS. 10 (a) and 10 (b), the catalyst element support 3 at the end of the catalyst unit 4 and the peak 2 of the catalyst element 10 shown in FIG. ), (b), the element support portion 3 at the end of the unit closes the inlet (or outlet) of the exhaust gas flow path, and it is difficult for gas to flow, and ash and dust may accumulate. Furthermore, ash deposition occurs at the part where the element support part 3 and the element peak part 2 at the end of the catalyst unit shown in the shaded part of FIGS. 10 (a) and 10 (b) overlap from the central part of the catalyst unit flow path. As a result, ash accumulation may increase. In such a case, the catalyst surface area decreases from the vicinity of the support portion 3 at the end of the catalyst unit, and the performance of the catalyst cannot be exhibited to the maximum extent.
An object of the present invention is to provide a plate-like catalyst structure in which the catalyst element structure at the unit end of the conventional catalyst production body is improved and accumulation of ash and dust in the exhaust gas is prevented.

In order to solve the above problems, the invention claimed in the present application is as follows.
Comprising the catalyst component is carried on the plate body protruding column portion and the concave-row portion of the flat plate portion and a predetermined height (crest) is made and a those formed in rows alternately in a plurality of rows alternately the plate-like catalyst elements, a catalyst structure comprising stored in stacked and the frame-shaped units,
The unit has a support portion for the plate-like catalyst element at an end portion on the exhaust gas flow path side, and a flat plate portion at the end portion of the plate-like catalyst element is disposed on the support portion,
Wherein a ratio of the plate length l of the unit end with respect to the length L of the supporting portion (l / L) of 2.0 or more, and a flat plate length l of the unit end of the exhaust gas flow path between the plate-shaped catalyst element widths A plate-like catalyst structure for exhaust gas treatment, wherein w or less (l ≦ w).

According to the present invention, it is possible to prevent a decrease in gas flow rate by disposing a portion of the catalyst structure that does not have a peak portion of the catalyst element at the end of the unit, so that ash accumulation in the flow path can be prevented, The catalyst performance can be maximized.
As a result of examining the dimensions of the peak portion 2 and the element end support portion 3, the present inventors have confirmed that the peak portion 2 and the support portion 3 at the unit end portion do not overlap, that is, the catalyst element on the support portion 3 at the unit end portion. The present inventors have found that the ash accumulation starting from the end of the catalyst unit can be reduced by adopting a structure that does not have the crest 2 of the above.

  That is, according to the present invention, a structure in which the ratio (l / L) between the length L of the element support portion 3 at the unit end and the flat plate length l at the unit end is 2.0 or more is shown in FIG. Since the ash accumulation in the shadow portion 8 of (a) and (b) can be suppressed, the effective area of the catalyst can be maintained, and the catalyst performance can be maximized. This effect can be obtained not only in the structure having the Z-shaped peak in FIG. 10 (a) but also in the structure having the W-shaped peak in FIG. 10 (b).

  Further, by making the element support portion 3 at the unit end and the flat plate length l at the unit end equal to or less than the width w of the catalyst flow path, the flat plate portion at the end of the catalyst element is curved as shown in FIG. It can prevent that the element flat plate part adjacent to a lamination direction contacts. Preferably, if l / L> 2.0 and w> l, there is no problem because there is no contact between adjacent element flat plate portions, and more preferably, the curvature of the element is relaxed when a catalyst structure is formed. When the flat plate portions at the end portions of the elements are laminated, it may be adjusted at the time of processing so as to become a parallel flat plate.

1 is a cross-sectional view of a catalyst structure in Example 1. FIG. Sectional drawing of the catalyst structure in Example 2. FIG. FIG. 3 is an enlarged cross-sectional view of a catalyst structure in Example 2. The expanded sectional view of the catalyst structure in the comparative example 1. The expanded sectional view of the catalyst structure in the comparative example 2. The expanded sectional view of the catalyst structure in comparative example 3. The expanded sectional view of the catalyst structure in comparative example 3. Explanatory drawing of the flow-path cross section of the catalyst structure in this invention. The perspective view of a catalyst element. The perspective view of a catalyst structure. Explanatory drawing of a catalyst unit. Sectional drawing of the conventional plate-shaped catalyst structure (mountain Z type). Sectional drawing (mountain W type) of the conventional plate-shaped catalyst structure.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The evaluation in the test of the catalyst structure in the examples was the shape, ash deposition, and effective area ratio, the shape was visually confirmed, and the ash deposition status was confirmed using the powder flow test apparatus under the conditions shown in Table 1. . The effective area ratio was calculated based on the surface area before ash deposition and the surface area excluding the ash deposition part, and the comparison was made with Comparative Example 1 as 1.0.

  A catalyst component is applied to stainless steel expanded metal, and then processed so that the height of the crest is 5.7 mm, and the catalyst gas flow direction length is cut to 500 mm and the width to 150 mm. Element. At this time, the ratio (l / L) between the length L of the element support portion and the flat plate length l at the end of the unit was 2.0 and l <w. Thereafter, the catalyst elements were stacked and stored in a unit as shown in FIGS. 1 and 8, and assembled into a catalyst structure.

After the catalyst component was applied to the expanded metal in the same manner as in Example 1, a catalyst body in which the length l of the plate up to the peak of the element was made longer than in Example 1 as shown in FIG. Thus, a catalyst structure as shown in FIG. 8 was manufactured. At this time, l / L = 4.0 and l = w.
In this example, ash deposition and effective catalyst area were improved compared to Comparative Example 1, but the shape when the catalyst was laminated was the same as that of the flow path near the element support, as shown in Fig. 2 (b). The bending was reduced by the adjustment during processing, and there was no overlap of adjacent elements in the stacking direction.

[Comparative Example 1]
After applying the catalyst component to the expanded metal in the same manner as in Example 1, a catalyst body having l / L = 0.5 and l <w as shown in FIG. 3 was produced.
In this example, more ash was deposited than in each example, and the catalyst effective area was lower than in each example.
[Comparative Example 2]
After applying the catalyst component to the expanded metal in the same manner as in Example 1, a catalyst body with l / L = 1.5 and l <w was obtained as shown in FIG. In this example, ash accumulation was observed, and the effective area was lower than in each example.

[Comparative Example 3]
After applying the catalyst component to the expanded metal in the same manner as in Example 1, the l / as shown in FIG.
L = 5.0, a catalyst body in which the flat plate length l at the end of the unit was larger than the width w of the flow path at the center of the catalyst structure (l> w).
In this example, the ash deposition was the same as in each example, but the shape when the catalyst was stacked is very good because the adjacent elements overlap in the stacking direction as shown in Fig. 5 (b). Absent.
According to the catalyst structure of the present invention, there is almost no ash deposition and the effective catalyst area is larger than that of the conventional catalyst structure shown in Comparative Example 1. This is considered to be an effect of securing the flow path by eliminating the overlap between the element support portion and the element peak portion as shown in FIG.

1. Flat plate
2. Yamabe
3. Element support at the end of the catalyst unit
4. Catalyst unit
5. Support length of catalyst element
6. Element flat plate length at the end of the catalyst unit
7. Catalyst channel width
8. Ash accumulation part
10. Catalytic element

Claims (1)

Comprising the catalyst component is carried on the plate body protruding column portion and the concave-row portion of the flat plate portion and a predetermined height (crest) is made and a those formed in rows alternately in a plurality of rows alternately the plate-like catalyst elements, a catalyst structure comprising stored in stacked and the frame-shaped units,
The unit has a support portion for the plate-like catalyst element at an end portion on the exhaust gas flow path side, and a flat plate portion at the end portion of the plate-like catalyst element is disposed on the support portion,
Wherein a ratio of the plate length l of the unit end with respect to the length L of the supporting portion (l / L) of 2.0 or more, and a flat plate length l of the unit end of the exhaust gas flow path between the plate-shaped catalyst element widths A plate-like catalyst structure for exhaust gas treatment, wherein w or less (l ≦ w).

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