JPH025445B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to the structure of an apparatus for denitrifying exhaust gas without the risk of gas leakage due to thermal deformation and accompanying cracks.

<Prior art and its problems> Dry exhaust gas denitrification equipment forms a catalyst layer in the high-temperature boiler exhaust gas flow path, and injects a denitrification agent such as ammonia upstream, thereby reducing the amount of exhaust gas in the exhaust gas as it passes through the catalyst layer. It decomposes nitrogen oxides into water (H ₂ O) and nitrogen gas (N ₂ ). Among these, the parallel flow type denitrification reactor is a device that incorporates a catalyst layer formed by a plate catalyst, a honeycomb catalyst, etc., and is characterized by a small pressure loss when gas passes through the catalyst layer. For this reason, parallel flow denitrification reactors can be used with existing boilers.
It has the advantage that it can be used by being placed between the outlet of the economizer and the air preheater without installing a new blower or the like. However, since both the economizer and the air preheater are located within the duct of the boiler, the flow direction of the exhaust gas to be introduced into the denitrification reactor must be reversed by 180 degrees at some point. Normally, the flow direction of exhaust gas is reversed in a denitrification reactor, and FIG. 1 shows the structure of an example of a conventional denitrification reactor in which the flow direction of exhaust gas is reversed. The exhaust gas passes through the inlet duct 12 and reaches the denitrification reaction catalyst layer 6.
After passing through, the flow direction is changed by the current plate 8 and reaches the outlet duct 7. In this denitrification reactor, the outlet duct 7 is supported by a reinforcing steel frame 11 that supports the denitrification reaction catalyst layer 6. That is, the reinforcing steel frame 11 supports the upper duct 7 by passing through the ceiling 12a of the lower duct 12 and supporting the bottom plate 7a of the duct 7. However, since a space 14a is formed between the upper duct 7 and the lower duct 12, a large temperature difference occurs between the inside of each duct and this space 14, and there is a risk that the entire denitration reactor may be thermally deformed. . For this reason, in FIG. 1, telescopic members 10a and 10ob for absorbing lateral displacement
Furthermore, in order to absorb displacement in the vertical direction, it is necessary to separately arrange an elastic member 15 at the connection between the lower duct 12 and the upper duct 7, which complicates the overall structure of the device. Furthermore, the reinforcing steel frame 11 also generates a large temperature difference between the inside of the lower duct 12 and the part located in the space 14, causing distortion in the reinforcing steel frame itself, and also due to relative movement with the bottom plate 7a of the outlet duct 7. , there is also a risk of damaging the bottom plate 7a.

<Objective of the Invention> The object of the present invention is to eliminate the drawbacks of the prior art described above, to provide a denitrification reactor which suffers less thermal deformation and has a simple structure.

<Summary of Means> In short, this invention arranges an inlet duct with a square cross section on the lower side and an outlet duct with a square cross section on the upper side, and uses a reinforced steel frame with horizontally movable legs to support the denitrification reaction catalyst layer. In the supported denitrification reactor, a partition plate having a gap with the upper surface of the denitrification reaction catalyst layer and extending horizontally from the downstream end of the inlet duct is used as the bottom plate of the outlet duct, and the inlet duct and the outlet duct are connected to the reactor. This denitrification reactor is characterized in that it is connected by a casing to form a reverse flow path for exhaust gas.

<Example> An example of the present invention will be described below with reference to FIG.

In the figure, reference numeral 9 is a reactor casing that reverses the exhaust gas flow and connects the inlet duct and the outlet duct. The partition plate 13 has a gap with the upper surface of the denitrification reaction catalyst layer, and extends horizontally from the downstream end of the inlet duct 12a, serving as the bottom plate of the outlet duct 7b. The legs of the reinforcing steel frame 11a that holds the denitrification reaction catalyst layer 6 in the inlet duct 12a can be freely displaced in the horizontal direction, so that even if the members of the denitrification reactor undergo thermal expansion due to exhaust gas, no damage such as cracks will occur. . Reference numeral 8 is provided to change the direction of the exhaust gas flow by 90 degrees, reduce flow resistance, and rectify the flow. The partition plate 13 is the bottom plate of the outlet duct, and is shaped like a part of the ceiling plate of the inlet duct. Therefore, since there is no space 14 shown in FIG. 1, there is no need for telescopic members such as 10a, 10b, and 15. Exhaust gas leaving the outlet duct flows downstream to the air preheater.

<Effect of the invention> By implementing this invention, the partition plate 13
Since a horizontally movable reinforcing steel frame 11a supporting the denitrification reaction catalyst layer 6 is used, there is no occurrence of cracks due to thermal stress, and the life of the apparatus can be extended.

Furthermore, there is no need to arrange an expandable member at the joint between the inlet duct and the outlet duct, which simplifies the structure and reduces manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a conventional parallel flow type denitrification apparatus, and FIG. 2 is a side sectional view of a denitrification reactor according to an embodiment of the present invention. 6... Denitrification reaction catalyst layer, 9... Reactor casing, 11, 11a... Reinforced steel frame, 12, 12a...
...Inlet duct, 13...Partition plate.

Claims (1)

[Claims] 1. In a denitrification reactor in which an inlet duct with a square cross section is disposed on the lower side, an outlet duct with a square cross section is arranged on the upper side, and a denitrification reaction catalyst layer is supported by a reinforced steel frame with horizontally displaceable legs, A partition plate that has a gap with the upper surface of the denitrification reaction catalyst layer and extends horizontally from the downstream end of the inlet duct serves as the bottom plate of the outlet duct, and the inlet and outlet ducts are connected by a reactor casing to prevent the reverse flow of exhaust gas. A denitrification reactor characterized by forming a flow path.