JPH0226620A - Dust removing device of denitrification apparatus - Google Patents

Abstract

PURPOSE:To provide a dust removing device of simple construction by providing one or more hinge type dampers on the upstream or downstream aide of a catalyst-filled zone in the vicinity thereof. CONSTITUTION:In the vicinity of a catalyst-filled layer 2 a hinge type damper 7 which acts on a fulcrum 6 is provided so that the vane of the damper is operated alternately to raise the flow speed of gases passing through catalyst 2, so that dusts deposited over the whole region of the catalyst are removed. The hinge type damper 7 can be provided close to the catalyst 2, so that the construction of dust removing device can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a dust removal device for preventing functional deterioration and pressure loss increase due to dust adhesion to a catalyst-packed portion of a denitrification device.

[Conventional technology]

A conventional method for removing dust attached to a catalyst filling part in a denitrification device will be explained with reference to FIG. 6. This embodiment shows the case of vertical gas flow, and the denitrification device has a catalyst 2 supported and built in a denitrification reactor 1 by a catalyst support member 3.

The inlet exhaust gas 4 flows vertically through the inlet catalyst section from the top of the catalyst 2 to become the outlet exhaust gas 5. However, the gas passage is divided above the catalyst 2, and the separation of the gas passing through the catalyst (the distance between the catalyst and the catalyst is minimized) A partition plate 11 is arranged so as to minimize leakage of gas into the other divided passage.A butterfly damper 9 is installed in each gas passage formed by the partition plate 11. 10 is supported and installed by the fulcrum 6. In addition, in FIG. 6, the dotted line indicates the state in which the butterfly dampers 9 and 1o are blocking the gas flow.
- The dashed dotted line indicates the moving direction of the butterfly dampers 9, 10.

In such a device, while the denitration device is operating, one of the butterfly dampers, such as butterfly damper 9, is operated in the closing direction so as to gradually block the gas flow (it is not necessarily necessary to fully open the butterfly damper). (No), the gas flow rate in the other gas passage is increased to a required value, and the gas flow rate passing through the catalyst holes is increased, so that the dust attached to the catalyst is transported and removed by the mass flow of exhaust gas.

After removing the dust from one catalyst layer, the butterfly damper 9 is returned to the fully open state, and the other butterfly damper 10 is operated in the same manner as described above to remove the dust from the other catalyst layer.

[Problem to be solved by the invention]

As for the self-cleaning action of the exhaust gas itself, increasing the flow rate of the exhaust gas is the quickest method, and the inventor's tests have confirmed the effect as shown in FIG. 5. That is,
If the flow velocity in the catalyst hole is set to a speed higher than 11 m/sec, for example, dust adhering to the catalyst will be removed by the mass flow of exhaust gas!
It can be seen that as the flow rate increases, the time required for dust removal decreases and the effect increases.

On the other hand, the catalyst pressure drop increases as the flow rate increases, and the permissible limit of this value depends on the limits for each individual plant. However, a certain increase in catalyst pressure loss within the allowable limit is permissible for a short period of time (within several minutes).

However, the conventional dust removal device described above has the following problems.

■ Since it is a butterfly damper, it must be installed at a distance from the catalyst, so in order to prevent gas leakage, a partition plate adjacent to the catalyst and dividing the gas passage is essential.

■ At least two or more sets of butterfly dampers are required.■ Due to the reasons shown in (1) and (3) above, the mechanism is complicated and costs are high.

In view of the above state of the art, the present invention aims to provide a dust removal device for a denitrification device that has a simple structure and can be inexpensive.

[Means to solve the problem]

The present invention provides an apparatus for denitrating exhaust gas containing a large amount of dust using a catalyst, in which one or more hinged dampers are provided on the upstream or downstream side of the catalyst filling section, in the vicinity of the catalyst filling section. This is a dust removal device for a denitrification device.

[Effect]

Since it is a hinge type damper, it can be installed close to the catalyst filling part, so it is not necessary to provide a partition plate, and by moving the hinge type damper to the left or right, the gas flow path can be changed and the gas flowing The flow rate is increased to remove dust attached to the catalyst layer. The device of the present invention is particularly effective when a parallel flow type catalyst is used as the catalyst.

The hinge type damper as used in the present invention refers to a damper that can move horizontally through 180 degrees around a fulcrum. In contrast, a conventional butterfly damper can move through 360 degrees around a fulcrum.

〔Example〕

Various embodiments of the present invention will be explained with reference to FIGS. 1 to 4. In FIGS. 1 to 4, the same reference numerals as in FIG. 6 mean the same parts as in FIG. 6, and therefore the explanation will be omitted.

In the embodiment shown in FIG. 1, 7 is a hinged damper that operates around a fulcrum 6 provided close to the packed bed of catalyst 2, the dotted line indicates the usage state of the damper 7, and the dashed line indicates the damper. 7 shows the direction of movement.

During operation of the denitrification device, the blades of the damper 7 are alternately operated to increase the gas flow rate passing through the catalyst 2, thereby removing dust attached to the entire area of the catalyst.

The embodiment shown in FIG. 2 shows a case where the blades of the hinge type damper 7 shown in FIG. 1 do not cover the entire gas passage on one side even when in use. The purpose of the damper 7 is to increase the flow rate of gas passing through the catalyst to an appropriate value for removing attached dust.
This may be done if the flow velocity during normal operation is originally high.

In the embodiment shown in FIG. 5, the denitrification reactor 1 is relatively large.
A case is shown in which a plurality of hinge type dampers 7 are arranged in order to downsize the hinge type damper 7 and its drive mechanism.

The embodiment shown in FIG. 4 shows a case where the hinged damper 7 in FIG. 1 is arranged upstream of the catalyst 2.

〔Effect of the invention〕

According to the present invention, by providing the hinge type damper close to the catalyst packed bed, it is possible to provide a dust removal device for a denitrification device with a simplified structure.

[Brief explanation of the drawing]

Figures 1 to 4 are schematic diagrams showing embodiments of the invention, and Figure 5 shows the relationship between the gas flow rate in the catalyst hole (m/sec), the time required for complete removal of attached dust (sec), and the catalyst pressure loss (mAq). FIG. 6, a chart showing the relationship, is a schematic diagram showing one aspect of a conventional dust removal device of a denitrification device.

Claims (1)

[Claims] An apparatus for denitrating exhaust gas containing a large amount of dust using a catalyst, characterized in that one or more hinged dampers are provided close to the catalyst filling part and on the upstream or downstream side thereof. Dust removal device for denitrification equipment.