JP4977456B2 - Catalyst structure and exhaust gas purification apparatus using the catalyst structure - Google Patents

Description

  The present invention relates to a catalyst structure for purifying exhaust gas and an exhaust gas purification apparatus using the catalyst structure.

  The shape of the catalyst conventionally used for exhaust gas treatment includes various shapes such as a plate shape, honeycomb shape, granular shape, cylindrical shape, ribbon shape, pellet shape, etc. It has the advantage that the pressure loss is lower than the shape. Furthermore, it is manufactured by various manufacturing methods, such as a manufacturing method in which a catalyst component is applied to a metal or ceramic substrate, and a method in which the catalyst component is supported on the surface of a carrier that has been molded in advance to maintain the required strength. Has the advantage of being able to

  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 increased to maintain the strength, and it is necessary to sacrifice the reaction efficiency of a part of the catalyst. On the other hand, in the case of the catalyst plate, since the strength can be maintained by the substrate or the carrier, the catalyst component also has an advantage that the composition can maximize the reaction efficiency. By selecting a substrate as necessary, it has a feature of being resistant to wear even when applied to a gas containing a lot of dust.

  As an exhaust gas purification apparatus using such a catalyst plate, the one described in Patent Document 1 is known. According to this, the catalyst plates are bent to form ridges extending in the gas flow direction in a row, the positions of the ridge portions of the plurality of catalyst plates are shifted and overlapped, and the intervals between the catalyst plates are set using the ridge portions as spacers. It has been proposed to solve the problem of the catalyst unit being held. That is, the cross-sectional area of the gas flow path formed by being sandwiched between the catalyst plates becomes large at the position of the peak portion, and the gas flow in the flow path can be biased, so that the catalytic reaction efficiency decreases. Therefore, according to the same literature, there is provided a catalyst structure that forms valleys that are bent in the opposite direction with appropriate intervals in the extending direction of the peaks, and that allows the flow paths on both sides of the catalyst plate to communicate to alleviate the drift. Proposed.

JP-A-10-28871

  However, since the catalyst plate described in Patent Document 1 must be cut at regular intervals in the catalyst plate at the time of production and passed through a specially shaped roller to form peaks and valleys, There is a problem that the manufacturing process becomes complicated.

  The problem to be solved by the present invention is to prevent the drift in the flow path formed by being sandwiched between the catalyst plates, and to simplify the manufacturing process of the catalyst plates.

  In order to solve the above problems, the catalyst structure of the present invention has a plurality of catalyst plates on which a catalyst for purifying exhaust gas is supported so that the plate surfaces are parallel to the gas flow direction, and The upper and lower plate surfaces are orthogonally stacked in a plurality of stages and arranged in a plurality of stages, and cut portions are provided at equal pitches at the ends of the upper and lower stack portions of the catalyst plate, and the upper and lower catalyst plates are combined with the cut portions. And a support member that supports the catalyst plate is installed at the uppermost and lowermost stages of the catalyst plate, and the support member is disposed so as to extend in a direction perpendicular to the plate surface of the catalyst plate. The member and the catalyst plate are formed with cut portions having an equal pitch at portions where they are in contact with each other, and the cut portions are supported in combination with each other.

  That is, according to the present invention, since each catalyst plate is formed of a simple flat plate, the cross-sectional area of the gas flow path sandwiched between the catalyst plates can be formed evenly in the plate width direction, and gas flow drift can be suppressed. In other words, since there are no bent portions or the like that disturb the gas flow in the flow path formed by the opposed catalyst plates, it is possible to suppress the drift.

  In addition, the catalyst plates are stacked one above the other with the plate surfaces orthogonal to each other, and the cut portions provided at equal pitches at the ends of the stacked portions are stacked in combination with each other. Since the support member for supporting the end portion of the catalyst plate is installed in the lower stage, similarly to the stacked portion of the catalyst plate, the catalyst plate can be held at an equal pitch without providing a spacer. Furthermore, since a bent part is not required, the manufacturing process can be simplified. Further, if the support member installed at the uppermost stage is a plate-like support plate and the plate surface is arranged parallel to the gas flow direction, it acts as a rectifying plate for rectifying the gas flowing into the catalyst structure inlet. Further, if both the upper and lower support members have the same shape, the cost can be reduced.

  In the above case, the cut portion provided in the catalyst plate can be a sine wave shape, a triangular wave shape, or a slit.

  ADVANTAGE OF THE INVENTION According to this invention, the drift of the flow path formed between catalyst plates can be prevented, and the manufacturing process of a catalyst plate can be simplified.

  Hereinafter, the present invention will be described based on embodiments. FIG. 1 is an exploded perspective view of a catalyst structure according to an embodiment of the present invention, and FIG. 2 is an assembled perspective view. As shown in the figure, in the catalyst structure of the present embodiment, the catalyst plate 1 carries a catalyst for purifying exhaust gas, and is arranged so that the plate surface is parallel to the gas flow direction. is doing. The catalyst plate 1 is placed in a packed box 2 by being stacked in a plurality of stages with the upper and lower plate surfaces perpendicular to the gas flow. The filling box 2 has an open end opposite to the top and bottom.

  The catalyst plate 1 is provided with sinusoidal cut portions 1A (FIG. 3) at equal pitches at the upper and lower ends, and the upper and lower catalyst plates 1 are stacked by combining the cut portions. An upper support plate 3 and a lower support member 4 that support the catalyst plate 1 are installed on the uppermost and lowermost stages of the catalyst plate 1. The support plate 3 and the support member 4 are attached to a frame 5 formed with the same dimensions as the filling box 2. The support plate 3 and the support member 4 extend perpendicularly to the plate surface of the catalyst plate 1, and the cut portions 3 </ b> A and 4 </ b> A having an equal pitch are provided at portions in contact with the catalyst plate 1, and the cut portions are combined with each other. To support. Here, the cut portion 3A provided in the support plate 3 has a sinusoidal shape, and the cut portion 4A provided in the support member 4 is a slit. If necessary, the cut portions of the catalyst plate 1 and the support plate 3 may be triangular wave cut portions 1B (FIG. 4) or slit cut portions 1C (FIG. 5).

  Thus, according to the present embodiment, each catalyst plate 1 is formed as a simple flat plate, and the catalyst plates 1 are in contact with each other vertically so that they do not move due to the combination of the cut portions 1A and the action of their own weight. As a result, the cross-sectional area of the gas flow path sandwiched between the catalyst plates 1 can be formed uniformly in the plate width direction, and the drift of the gas flow flowing through the catalyst structure from top to bottom or from bottom to top Can be suppressed.

  In other words, an important point in designing the catalyst structure is that the flow velocity distribution does not vary in the cross section of the flow path surrounded by the catalyst plate. When the same catalyst component is used, for example, the denitration rate when there is a variation in speed is lower than when it is flowing uniformly.

  Conventionally, the catalyst plates are bent to form the crests extending in the gas flow direction in a row, the positions of the crest portions of the plurality of catalyst plates are shifted and overlapped, and the crest portions are used as spacers to maintain the distance between the catalyst plates. In such a case, there is a problem that microscopic flow velocity variation occurs in the cross section of the gas flow path or extremely high pressure loss occurs. In the present embodiment, all the catalyst plates 1 are simply flat plates having no bent portions as described above, and the cross section of the gas flow path can be ideally uniform. And gas blow-through can be suppressed. That is, the performance of the catalyst itself can be fully exhibited by suppressing the drift.

  The support plate 3 installed on the uppermost stage of the catalyst plate 1 is arranged so that the plate surfaces are parallel as shown in FIG. The support plate 3 is disposed and supported so that the plate surfaces of the catalyst plate 1 and each other are orthogonal to each other, and an effect of preventing the catalyst plate from moving in a direction perpendicular to the gas flow can be obtained without providing a spacer. . Furthermore, by providing the support plate 3 with the cut portions 3A, an effect of further preventing the catalyst plate from moving in the direction perpendicular to the gas flow can be obtained. Further, the support plate 3 functions as a rectifying plate that rectifies the gas flowing into the catalyst structure entrance. If the lower support member 4 is formed in a columnar shape or a cylindrical shape, the clogging of ash, which has been a problem in the conventional catalyst unit structure, can be suppressed. By providing the cut portion 4A, it is perpendicular to the gas flow. An effect of preventing the movement is also obtained.

  Further, in order to maintain the structure of the catalyst structure according to the present embodiment, it is necessary to have a sufficient strength against the stress generated when the actual machine is used. If the length of the catalyst plate 1 is too long, buckling or deflection will occur due to its own weight. Therefore, the length of the catalyst plate 1 is preferably 450 mm or less.

  The cut portions 1A provided at the upper end and the lower end of the catalyst plate 1 do not necessarily have the same shape, but the upper and lower end portions of the plate-like catalyst plate that has been preliminarily coated with a catalyst and roll-formed are continuously formed by a cutter. Since the cut portion is provided by cutting, the manufacturing cost can be reduced by making the shape of the cut portion of the upper end portion and the lower end portion the same.

  Here, as shown in FIG. 5, in the case of the catalyst plate 1 provided with the slit cut portion 1 </ b> C, the cross section of the connection portion between the catalyst plates is substantially in a honeycomb shape, and the connection portions are adjacent to each other. This is not preferable because the gas flow rate on the catalyst surface (corner portion) decreases and ash is likely to accumulate on the catalyst plate.

  In addition, when the cut portion has a sine wave shape (FIG. 3) and a triangular wave shape (FIG. 4), when the distance between the inner vertex 6 and the outer vertex 7 of the cut shape where the catalyst plates are in contact with each other is large, the cut portion is a slit. It becomes close to such a shape and causes ash accumulation. In order to avoid this, it is desirable that the ratio between the length between the inner vertex 6 and the outer vertex 7 of the cut shape provided in the catalyst plate and the total length of the catalyst plate is 1:50 or less.

  The support member 4 can be formed in the same shape as the support plate 3. According to this, the cost can be reduced, and in particular, when applied to a gas not containing dust, this method is effective because there is no risk of ash blockage.

  Further, in the conventional catalyst device, a plurality of catalyst bodies molded into a predetermined shape are arranged and accommodated in a case (catalyst block), and the catalyst block is filled in the reactor. In the present embodiment, the catalyst structure is a single structure that constitutes the current plate, the catalyst plate, and the support member. That is, since the catalyst structure can be filled directly into the reactor without using a catalyst block, the mass of the catalyst portion can be reduced, and a compact and low-cost apparatus can be obtained.

  Further, the present embodiment provides a catalyst structure that eliminates the non-uniformity of the gas flow rate at the time of passing gas and fully exhibits the catalyst performance, and does not stick to the composition of the applied catalyst. The catalyst plate can also be produced by several production methods, such as those applied to a metal or ceramic substrate and those supported on the surface of a carrier. Furthermore, there is no restriction | limiting by a manufacturing method especially if it is set as the catalyst plate formed in plate shape, You may manufacture combining a manufacturing method other than the above, or several manufacturing methods. In addition, the purpose is to improve the performance by the shape of the catalyst plate, so its use is not limited to denitration catalyst or oxidation catalyst, but it can be applied to general processes in which a gas containing a reactant is circulated through the catalyst to cause a reaction. Is possible.

  In addition, as shown in FIG. 6, the conventional packing box supports the catalyst plate 8 by providing a bent portion 9 on at least one lower surface. However, when processing a gas containing a large amount of dust, a region 10 in which ash tends to accumulate is formed, dust is accumulated on the bent portion 9, or a part of the gas flow path is blocked, resulting in a decrease in catalyst performance. There is a risk. Further, even when cleaning or comprehensive regeneration is performed in order to recover the performance of the used catalyst plate, the dust accumulated in the bent portion 9 becomes an obstacle to the performance recovery.

  Next, examples in which the present embodiment is applied and analyzed by experiments and comparative examples thereof will be described.

As an example of the catalyst structure according to the present invention, the catalyst structure shown in FIG. 2 was manufactured by the process shown in FIG. 7, that is, the process shown below. First, a catalyst component was applied to a stainless steel expanded metal, and roll forming was performed using a roller 11 so as to have a width of 500 mm. The catalyst plate 1 was manufactured by cutting the catalyst plate formed into a plate shape with a cutter 13 at a position having a length of 450 mm. The shape of the cutter 13 was such that the upper and lower cuts of the catalyst plate 1 had a sine wave shape as shown in FIG. The catalyst plate 1 was filled in a holding jig 14 for holding the catalyst plate at an equal pitch installed on the downstream side. The holding jig 14 was provided with a slit so that the catalyst plate could be filled at a necessary interval, and the catalyst plate 1 was inserted into this slit. The holding jig 14 itself can move in a direction perpendicular to the plate surface so that the catalyst plate 1 can be continuously filled. After one catalyst plate 1 is filled, the holding jig 14 moves to the next slit. The next catalyst plate 1 moves horizontally so that it can be installed on the holding jig 14. After the 80 catalyst plates 1 are filled, the jig filled with 1 unit of catalyst plate 1 is rotated by 90 °, and the catalyst plate 1 is filled again in the same manner as before, and finally a plurality of catalyst plates 1 are filled. The catalyst plate 1 was held in an engaged state so as to form a unit, and this was put in a packed box 2. A support plate 3 provided with a sinusoidal cut portion 3A was installed at the uppermost stage of the filling box 2, and a support member 4 provided with a slit cut portion 4A was installed at the lowermost stage. As the catalyst component, a denitration catalyst mainly composed of TiO ₂ was used. With respect to the obtained catalyst structure, the denitration performance and the pressure loss of the catalyst portion were measured under the conditions shown in Table 1. In the measurement, no abnormality in strength was observed, and the catalyst plate did not buckle or deform.

  A catalyst structure was produced by providing triangular wave cut portions 1B shown in FIG. 4 at the upper and lower ends of the catalyst plate 1. The same as Example 1 except for the catalyst plate. With respect to the obtained catalyst structure, the denitration performance and the pressure loss of the catalyst portion were measured under the conditions shown in Table 1.

  The catalyst structure shown in FIG. 8 was manufactured by using a packing box 15 in which the number of packing boxes for the catalyst structure was one instead of two. Otherwise, it was the same as Example 1. With respect to the obtained catalyst structure, the denitration performance and the pressure loss of the catalyst portion were measured under the conditions shown in Table 1.

  In the catalyst structure according to Example 1, stirring components 16 for stirring the flow of the non-treatment gas were installed between the plates of the catalyst plate 1 so as to have the layout shown in FIG. 9 to manufacture the catalyst structure. With respect to the obtained catalyst structure, the denitration performance and the pressure loss of the catalyst portion were measured under the conditions shown in Table 1.

Comparative Example 1
It was formed by bending a catalyst plate in which a catalyst component was applied to a stainless steel expanded metal. The bent portion was extended in the gas flow direction, and a peak portion and a valley portion were arranged in a line. Then, the positions of the peaks are shifted to overlap the catalyst plates, and the intervals between the catalyst plates are maintained using the peaks and valleys as spacers. This catalyst unit was placed in a packing box to produce a catalyst structure. The catalyst composition was the same as in Example 1. With respect to the obtained catalyst structure, the denitration performance and the pressure loss of the catalyst portion were measured under the conditions shown in Table 1.

Comparative Example 2
Corrugate is made by applying a catalyst component to stainless steel expanded metal and laminating a plate-shaped catalyst plate and a catalyst plate formed by continuously folding the plate-shaped catalyst plate in a corrugated row extending in the gas flow direction. Structured. A catalyst structure having the corrugated catalyst plate arranged in a packed box was manufactured. With respect to the obtained catalyst structure, the denitration performance and the pressure loss of the catalyst portion were measured under the conditions shown in Table 1.

Comparative Example 3
Using the catalyst plate 1 used in Example 1, the length of one catalyst plate was 550 mm, and a catalyst structure was prepared so as to have the same catalyst structure as in Example 1. About this, it tried to measure the denitration performance and the pressure loss of the catalyst portion under the conditions shown in Table 1, but the catalyst plate 1 was damaged and could not be used.

  The obtained measurement results are shown in FIG. 10 together with other examples and comparative examples as the denitration rate and the pressure loss ratio when the pressure loss in Example 1 is 1.

  In Example 1, since the uniform flow velocity distribution can be obtained by adopting the structure according to the present invention, the performance inherent in the catalyst can be sufficiently exerted, and the bent portion shown in Comparative Example 1 is provided under the same conditions. Compared with the catalyst plate, a high denitration rate could be obtained with the same pressure loss.

  In Example 2, the result was almost the same as in Example 1, and it was shown that it did not depend on the cut shape of the catalyst plate.

  In Example 3, the same result as in Example 1 was obtained, indicating that it was not affected by the number of packed boxes.

  In Example 4, although the pressure loss slightly increases due to the stirring parts, the gas flowing between the catalyst plates arranged in parallel is stirred by the stirring parts, so that the catalyst performance is greatly improved by forcibly turbulent gas. did. Since the pressure loss inside the catalyst structure is slightly increased, when there is a margin in the allowable pressure loss of the apparatus, a method of installing a stirring component as in this embodiment is preferable.

  In Comparative Example 1, the denitration rate was a low value compared to any of the Examples. This is because the gas flow cannot be made uniform due to the presence of the bent portion.

  In Comparative Example 2, the denitration rate was almost the same as that of the example, but the pressure loss was extremely high. This is because the wall surface resistance is increased because the cross-sectional shape of the flow path formed by the catalyst plate is substantially triangular.

1 is an exploded perspective view of a catalyst structure according to an embodiment of the present invention. 1 is an exploded view of a catalyst structure showing an embodiment of the present invention and Example 1. FIG. FIG. 3 is a diagram of a catalyst plate having a sinusoidal cut portion in an embodiment of the present invention. FIG. 3 is a diagram of a catalyst plate having a triangular wave cut in one embodiment of the present invention. The figure of the catalyst structure which inserted and combined the catalyst plate whose notch is a slit in one embodiment of the present invention. Structure of packing box used as conventional technology Production conceptual diagram of catalyst structure according to Example 1 Catalyst structure produced in Example 3 Example of installation of stirring parts manufactured in Example 4 Results of Examples and Comparative Examples

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Catalyst plate 1A Notch part 1B Notch part 1C Notch part 2 Filling box 3 Support plate 3A Notch part 4 Support member 4A Notch part 5 Frame

Claims (6)

  A plurality of catalyst plates carrying a catalyst for purifying exhaust gas are arranged so that the plate surfaces are parallel to the gas flow direction, and the upper and lower plate surfaces are orthogonally arranged in the vertical direction and stacked in multiple stages. And the upper and lower catalyst plates are stacked by combining the notch portions, and the catalyst plates are stacked at the uppermost and lowermost stages of the catalyst plates. A plurality of support members for supporting each of the catalyst plates are installed, and the support members are arranged so as to extend in a direction perpendicular to the plate surface of the catalyst plate, and the support member and the catalyst plate are arranged at an equal pitch at a portion in contact with each other. A catalyst structure in which a notch is formed and is supported in combination with each other.   2. The catalyst structure according to claim 1, wherein the support member arranged at the uppermost stage is a plate-like support plate, and the support plate has a plate surface parallel to the gas flow direction. Structure.   2. The catalyst structure according to claim 1, wherein a shape of the cut portion of the upper and lower stacked portions of the catalyst plate is a sine wave shape.   2. The catalyst structure according to claim 1, wherein the shape of the cut portion of the upper and lower stacked portions of the catalyst plate is a triangular wave shape.   2. The catalyst structure according to claim 1, wherein the shape of the cut portion of the upper and lower stacked portions of the catalyst plate is a slit.   An exhaust gas purification apparatus using the catalyst structure according to any one of claims 1 to 5.

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