JPH08187434A - Dentitrification reactor - Google Patents

Abstract

PURPOSE: To uniformly disperse the gaps between the inner walls of catalyst units and plate-shaped catalysts without offsetting them. CONSTITUTION: In a denitrification reactor consisting of plate-shaped catalysts 2 arranged in a gravity direction in parallel to the flow of exhaust gas, a plurality of catalyst units housing the plate-shaped catalysts 2 and a reaction container housing the catalyst units, the catalyst units are supported by bringing the inwardly turned slopes formed to the exhaust gas inlet and outlet horizontal parts of the case side plates 1a of the catalyst units into contact with the end parts of the plate-shaped catalysts. By this constitution, the gaps between the inner walls of the catalyst units and the plate-shaped catalysts are uniformly distributed up and down and the blow-through of exhaust gas is prevented to enhance denitrification efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a denitration reactor for flue gas denitration, and more particularly to a catalyst support structure suitable for reducing blow-through of treated exhaust gas in a reactor.

[0002]

2. Description of the Related Art As a technique for reducing nitrogen oxides, so-called NOx, in exhaust gas from boilers, etc., the NOx is reduced by contacting the exhaust gas with a reducing substance such as ammonia (NH ₃ ) gas in the presence of a catalyst. The catalytic catalytic reduction (SCR) method is widely used in domestic and overseas plants. By the way, in recent years, the amount of exhaust gas containing NOx tends to increase with the development of industry, and in order to comply with environmental standards, the N content will be even lower.
There is a trend to demand Ox (higher efficiency). The denitrification catalyst used in this selective catalytic reduction method is a method in which a plurality of single catalysts are once unitized and then a plurality of catalysts are unitized in order to uniformly and effectively pack and arrange them in an exhaust gas flue having a large cross-sectional area. Load the unitized one in the reactor,
Exhaust gas is passed through to carry out a predetermined reaction.

FIG. 6 is a partially cutaway side view of a conventional catalyst unit as seen from a direction orthogonal to the flow of exhaust gas.

1 is a catalyst unit, 1a is a case side plate, 1
Reference numeral b is a case cover plate, 2 is a plate-like catalyst, and 3 is a catalyst drop-out prevention support portion. As shown in FIG. 6, the conventional catalyst unit 1 has a plurality of plate-shaped catalysts 2 filled in a case composed of a case side plate 1a and a case cover plate 1b. The catalyst unit 1 has a catalyst drop-off prevention support portion 3 formed by bending the case side plate 1a at a right angle so that the filled plate-like catalyst 2 does not drop off from the case side plate 1a in the flow direction of the exhaust gas. 1a and a case cover plate 1b are arranged on both sides of the lower case side plate 1a so as to face each other, and their respective contact sides are welded.

FIG. 7 is a perspective view showing a general plate catalyst.

The plate-like catalyst 2 shown in FIG. 7 is disclosed in Japanese Examined Patent Publication Sho 58-50.
This plate-shaped catalyst 2 is disclosed in Japanese Patent No. 137.
Has a Z-shaped cross section and a flat plate portion, and is flexible to the external force of the catalyst itself, and a parallel flow type catalyst is formed only by stacking and filling in the case.

[0007]

However, the plate-shaped catalyst 2 is one in which the Z-shaped projection is formed by pressing after the catalyst component is carried on the metal substrate, and the tolerance of the width of the substrate and the substrate material. Since there is a difference in the amount of springback of the protrusion forming portion after the press working due to the rigidity of itself, a manufacturing tolerance occurs in the width dimension of the plate-shaped catalyst 2 after the forming work. Therefore, the case filled with the plate-shaped catalyst 2 needs to have a case size in consideration of the manufacturing tolerance of the plate-shaped catalyst 2, and the can-making tolerance is also necessary because the case itself has a welded structure.

FIG. 8 is a vertical cross-sectional view showing a state in which a plate catalyst of a conventional catalyst unit is loaded.

FIG. 8 is a view of the catalyst unit 1 viewed from the flow direction of the exhaust gas. A gap due to manufacturing tolerances of the filled plate catalyst 2 and the case, that is, the height direction of the case and the width direction of the plate catalyst 2 are shown. The dimensional difference ΔH is caused only on one side of the upper part because the plate-shaped catalyst 2 moves to the lower part of the case by its own weight.
The existence of such a gap ΔH only on one side of the plate-shaped catalyst 2 rather than on both sides reduces the throttling effect and reduces the resistance to the exhaust gas flow, and the exhaust gas passes through the gap ΔH without contacting the catalyst component. Since blow-through easily occurs, there is a problem that the denitration performance deteriorates. In order to avoid such a problem, the plate-like catalyst 2 in the case is arranged horizontally and the gap ΔH is evenly divided on both sides of the plate-like catalyst 2, so that the passage of gas in the gap can be reduced. Even if the plate-shaped catalyst 2 is arranged horizontally, the plate-shaped catalyst 2 is moved due to vibration or shock during the manufacturing process or transportation of the plate-shaped catalyst 2, so that the correction work of the moved catalyst position is newly added. This will result in an increase in correction work time.

There is also a method of filling the gap with a gas seal material, but this also requires the gas seal material and the filling work thereof, resulting in an increase in cost.

An object of the present invention is to disperse the gap between the inner wall of the catalyst unit of the denitration reactor and the plate catalyst.

[0012]

The above object is to provide a plate-like catalyst arranged parallel to the flow of exhaust gas and in the direction of gravity, a catalyst unit for accommodating a plurality of plate-like catalysts, and a plurality of catalyst units for a reaction vessel. In the denitration reaction device provided in the inside, it is achieved by adopting a structure in which the inclined surface facing inward at the exhaust gas inlet / outlet horizontal portion of the catalyst unit and the end portion of the plate-shaped catalyst are brought into contact with each other to be supported.

[0013] The above object is to provide a plate catalyst arranged in parallel to the flow of exhaust gas and in the direction of gravity, a catalyst unit for accommodating the plurality of plate catalysts, and denitration having a plurality of the catalyst units in a reaction vessel. In the reaction device, at the exhaust gas inlet and outlet horizontal portions of the catalyst unit, a member having a triangular cross section as viewed in a direction orthogonal to the flow of the exhaust gas is directed inward so that its slope contacts the end of the plate catalyst. It is achieved by arranging the plate-shaped catalysts to support the plate-shaped catalyst.

[0014] The above object is to achieve a denitrification which has a plate-like catalyst arranged in parallel to the flow of exhaust gas and in the direction of gravity, a catalyst unit for accommodating a plurality of the plate-like catalysts, and a plurality of the catalyst units in a reaction vessel. In the reactor, the horizontal plate of the catalyst unit is bent inward at the exhaust gas inlet and outlet of the catalyst unit to form a slope, and the slope and the end of the plate-shaped catalyst are brought into contact with each other to be supported. Achieved by

[0015]

According to the above structure, since the plate-like catalyst is supported by the slopes formed in the horizontal opening portions at both ends of the catalyst unit, the gap between the inner wall of the catalyst unit and the plate-like catalyst does not deviate to the upper part but is uniform in the upper and lower parts. Can be dispersed in.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

First, the structure of this embodiment will be described.

FIG. 1 is a perspective view of a catalyst unit showing the structure of an embodiment of the present invention.

As shown in FIG. 1, 1 is a catalyst unit, 1a
Is a case side plate, 1b is a case cover plate, 2 is a plate-shaped catalyst, and 4 is a catalyst support portion at the end of the case side plate 1a. The flow direction of the exhaust gas is indicated by arrows, and the plurality of plate-shaped catalysts 2 are packed in parallel with the flow of the exhaust gas and in the direction of gravity, and the upper end and the lower end are supported by the catalyst support portion 4.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 2 is a planer catalyst 2 in the catalyst unit of FIG.
Is viewed from a direction orthogonal to the flow of exhaust gas. The catalyst supporting portion 4 has ridges with a Δ-shaped cross section at both ends of the case side plate 1a, and the corners of the plate-shaped catalyst 2 to be filled have the case side plate 1a.
Of the Δ-shaped ridge of the catalyst supporting portion 4 of
The interval l ₁ between the ridges is set to be slightly shorter than the catalyst length l ₂ .

Next, the assembling method of this embodiment will be described.

FIG. 3 is a perspective view for explaining the assembling method of the embodiment of the present invention.

FIG. 3 shows a state before the catalyst unit 1 is assembled, which is rotated by 90 ° with respect to FIG. To fill the plate-shaped catalyst 2 in the case, the side edges of each of the case side plate 1a and the case cover plate 1b are welded to form an L-shape, and a predetermined number of the plate-shaped catalysts 2 are provided on the lower case cover plate 1b. After stacking, the other case side plate 1a is welded to the lower case cover plate 1b, and then the other case cover plates 1b are similarly attached to both case side plates 1a by welding.

According to this embodiment, the plate-shaped catalyst 2 to be filled can always be filled in the central portion of the case by using the inclined portion of the catalyst support portion 4Δ type ridge provided on the case side plate 1a as a guide.
As a result, the gap ΔH caused by the manufacturing tolerance can be dispersed on both sides of the catalyst without being concentrated on only one side, so that the resistance is increased and the blow-through of the exhaust gas can be reduced. Further, it is not necessary to correct the catalyst so that it is located in the center of the case at the time of production and construction of the device incorporating the catalyst unit 1,
You can save time.

FIG. 4 is a partial sectional view showing the structure of another embodiment of the present invention.

In this embodiment, the shape of the catalyst supporting portion 4 shown in FIG. 2 is a right-angled triangle in cross section. Since the case side plate 1a has a flat portion, when the exhaust gas is a vertical (vertical) flow, this The catalyst units 1 can be easily stacked.

FIG. 5 is a partial sectional view showing the structure of another embodiment of the present invention.

In this embodiment, the sectional shape of the catalyst supporting portion 4 at the end of the case side plate 1a is a combination of a member having a triangular cross section shown in FIG. 2 and a right triangle shown in FIG.

In each of the catalyst supporting portions 4 of the above embodiments, a member having a triangular cross section is used.
Even if a slope is formed by bending the inside of the opening at both ends of a, the same effect can be obtained, and the manufacturing cost is reduced.

[0031]

According to the present invention, an inclined portion is provided on the catalyst supporting portion at the case end of the catalyst unit, and a plate-shaped catalyst is brought into contact with and supported by the inclined portion, so that the inner wall of the catalyst unit and the plate-shaped catalyst are separated from each other. It is possible to uniformly disperse the gaps in the upper part and the lower part, and it is possible to obtain the effect of preventing blow-through of exhaust gas and improving the denitration efficiency.

[Brief description of drawings]

FIG. 1 is a perspective view of a catalyst unit showing a configuration of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a perspective view illustrating an assembly method according to an embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing the configuration of another embodiment of the present invention.

FIG. 5 is a partial cross-sectional view showing the configuration of another embodiment of the present invention.

FIG. 6 is a partially cutaway side view of a conventional catalyst unit viewed from a direction orthogonal to a flow of exhaust gas.

FIG. 7 is a perspective view showing a general plate-shaped catalyst.

FIG. 8 is a vertical cross-sectional view showing a state in which a plate catalyst of a conventional catalyst unit is loaded.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 catalyst unit 1a case side plate 1b case cover plate 2 plate-like catalyst 3 catalyst drop-out prevention support part 4 catalyst support part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B01J 19/24 B

Claims (3)

[Claims] 1. A denitration reaction apparatus having a plate-shaped catalyst arranged parallel to the flow of exhaust gas and in the direction of gravity, a catalyst unit containing a plurality of the plate-shaped catalysts, and a plurality of the catalyst units in a reaction vessel. In the denitrification reaction apparatus, the exhaust gas inlet / outlet horizontal portion of the catalyst unit and the end portion of the plate-shaped catalyst are brought into contact with and supported by an inclined surface inwardly inclined at the horizontal portion. 2. A denitration reaction apparatus having a plate catalyst arranged parallel to the flow of exhaust gas and in the direction of gravity, a catalyst unit containing a plurality of the plate catalysts, and a plurality of the catalyst units in a reaction vessel. At the inlet and outlet horizontal portions of the exhaust gas of the catalyst unit,
A member having a triangular cross section as viewed in a direction orthogonal to the flow of the exhaust gas is arranged inward so that its slope contacts the end of the plate catalyst, and the structure supports the plate catalyst. A denitration reactor characterized by: 3. A denitrification reaction device having a plate catalyst arranged parallel to the flow of exhaust gas and in the direction of gravity, a catalyst unit accommodating the plurality of plate catalysts, and a plurality of the catalyst units in a reaction vessel. In the structure, a horizontal plate of the catalyst unit is bent inward at the exhaust gas inlet and outlet of the catalyst unit to form an inclined surface, and the inclined surface and the end of the plate-shaped catalyst are contacted and supported. The denitration reactor is characterized in that