JPH0137700Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a high dust denitrification device.

[Prior Art] A denitrification catalyst is provided in a denitrification reactor to prevent air pollution, and denitrates _NOx in exhaust gas. Catalysts for denitrification equipment include lattice,
Various shapes are used, such as plate-like and granular. Examples of lattice catalysts are shown in Figures 2 and 3.
As shown in the figure, a lattice-shaped catalyst 1 is placed in a basket 2 of a predetermined size (for example, 1 meter square) with a large number of holes 3 formed in parallel to the gas flow direction. .

Further, the pitch size and the like of the meshes 3 of the conventional lattice-shaped catalyst are usually selected according to the exhaust gas properties, and the shape and size are unified.

Generally, in the case of coal-fired high dust denitrification equipment,
As shown in Fig. 4, the catalyst 1 is installed in three layers, and in order to prevent dust in the gas from accumulating ash on the top surface of the catalyst 1 and abrasion of the ends of the catalyst 1, the gas flow is made vertically downward. For example, catalysts with the same large pitch P of 7.5 mm were selected for the three layers of catalysts 1 and 3.

[Problem that the invention aims to solve] However, when the catalyst mesh pitch P is increased,
Since it is necessary to increase the wall thickness of the catalyst 1 from the viewpoint of strength, the gas contact area per unit volume of the catalyst is small, and the catalyst volume inevitably becomes large.
Because of the need for multiple layers, the reactor height and installation space were large.

Therefore, in the present invention, in a coal-fired high-dust denitrification device, the catalyst in the first layer, that is, the most upstream side of the gas flow, is affected by the gas flow.
Ash accumulation on the top surface of the catalyst and abrasion of the ends of the catalyst due to ash are considered, so a catalyst with a large mesh pitch is inevitably selected, but the gas flow is rectified to some extent from the second layer onwards, and the catalyst In order to reduce the accumulation of ash on the top surface and the wear of the end of the catalyst, the number of catalyst layers can be increased by reducing the size of the catalyst gas passage in the second and subsequent layers to increase the reaction efficiency while maintaining the same performance. The vertical stacking method makes it easy to maintain strength even when the thickness of the catalyst itself is reduced.
It is intended to solve the conventional reactor height problem.

[Means for solving the problem] The present invention stacks catalysts vertically so that the gas in the high dust denitrification equipment flows vertically, and Catalysts with a smaller mesh pitch are selected for the second and subsequent layers of catalysts, and the amount of catalyst and the number of catalyst layers are reduced while ensuring the same performance as the conventional system with multiple layers of catalysts with the same mesh pitch.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment of the high dust denitrification device of the present invention, in which the first layer is placed on the upstream side of the reactor 4.
The pitch of grid mesh 3 is the same as the conventional one.
The catalyst 1a with a pitch of 7.5 mm is used, and as the catalyst 1b of the second layer on the downstream side, a catalyst with a small pitch of 5 mm, for example, is selected, and the gas that has passed through the catalyst 1a of the first layer is selected. Subsequently, the gas is passed through a second layer of catalyst 1b with a small mesh size, during which denitrification is performed and the gas is discharged as _N2 .

With the above configuration, when gas enters the reactor from the direction of arrow a, the gas is bent into the first
The gas is passed through the grid _- like openings of the catalyst 1a in the layer, and during this time the gas is denitrated by contacting _the catalyst _1a , and _{the NO} be exposed. The _NOx contained in the gas that has passed through the catalyst 1a in the first layer undergoes a denitrification reaction while passing through the catalyst 1b with a small mesh size in the second layer, and the _NOx is finally reduced. and will be released into the atmosphere.

In this invention, the mesh pitch of the catalysts in the second and subsequent layers is set to the mesh pitch of the first layer catalyst 1a (7.5 mm pitch).
Since the pitch is 5 mm, which is smaller than the 5 mm pitch, it is possible to increase the gas contact area per unit catalyst volume, and when looking at the catalyst as a whole, the amount of catalyst can be reduced compared to the conventional three-layer installation. In addition, the number of catalyst layers can be reduced, and the height of the reactor can be reduced by maintaining the strength of the catalyst itself through the vertical stacking method.

[Effects of the invention] As described above, the high dust denitrification device of the present invention reduces the size of the catalysts in the second and subsequent layers, compared to at least three layers of conventional large-sized catalysts. Not only can the amount of catalyst be reduced while maintaining the same performance as in the conventional case, but the number of catalyst layers can also be reduced, and the vertically stacked structure makes it easier to maintain the strength of the catalyst itself, reducing the reactor height and installation space.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing one embodiment of the present invention;
The figure is a perspective view of a commonly used lattice catalyst, FIG. 3 is a partial plan view of FIG. 2, and FIG. 4 is a schematic diagram showing a conventional example. 1 is the catalyst, 1a is the first layer catalyst, 1b is the second layer catalyst
The number 3 indicates the catalyst layer, and the number 4 indicates the reactor.

Claims (1)

[Scope of utility model registration request] In a high-dust denitrification device that denitrates _NO A high-dust denitrification device, characterized in that the gas flow path size of the catalyst in the second and subsequent layers from the upstream side is smaller than the gas flow path size of the catalyst in the first layer.