JP3376511B2 - Ammonia gas injection device in denitration equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reducing agent ammonia gas in a denitration apparatus for removing nitrogen oxides (NOx) in exhaust gas from gas turbines and boilers by selective catalytic reduction. Related to an injection device. 2. Description of the Related Art As shown in FIG. 2, a denitration apparatus comprises a denitration reactor (21) and an ammonia injection grid (22) upstream thereof, and an exhaust gas outlet duct (23) of a gas turbine or a boiler. And is usually arranged in the exhaust heat recovery boiler (24). The ammonia injection grid (22) is shown in FIG.
4 and FIG. 4, the frame (27) and the frame (2
Multiple ammonia injection pipes (25) passed to the opposite part of 7)
And a plurality of supports (28) for supporting the pipe (25) on the frame (27) .A large number of injection nozzles (26) are equally spaced on both sides in the gas flow direction of each ammonia injection pipe (25). It is open at. And the ammonia injection grid (22)
The vaporized ammonia gas is injected into the exhaust gas by an amount equal to the NOx in the exhaust gas, and is reacted with a denitration catalyst in a denitration reactor (21) located a distance enough to uniformly diffuse the NOx in the exhaust gas, detoxifies NOx into N ₂ and H ₂ O. [0003] In the above denitration system, in order to improve the denitration rate, (a) the ammonia gas discharged from the ammonia injection grid (22) must be uniformly diffused in the exhaust gas. (B) It is important that the exhaust gas containing ammonia gas uniformly passes through the catalyst packed bed of the denitration reactor (21), so that the reaction occurs evenly in any place. For (a), Fig. 3
And an ammonia injection grid (22) as shown in FIG.
Are arranged so that a plurality of grid pipes (25) are evenly arranged in the cross section of the duct.
Ammonia gas is evenly ejected into the exhaust gas from the multiple injection nozzles (26) of (25). Further, the distance between the ammonia injection grid (22) and the catalyst packed layer of the denitration reactor (21) is increased to some extent to promote diffusion. However, in the above configuration, it is necessary to arrange a plurality of grid pipes densely to some extent, to make the amount of ammonia gas ejected from each nozzle uniform, and to make the injection grid (22) and the catalyst packed layer. There is a problem that there is a dimensional restriction for securing a predetermined distance between the two. In view of the above, it is an object of the present invention to shorten the distance between the ammonia injection grid and the denitration catalyst, increase the interval between a plurality of injection grid pipes, simplify the grid structure, and make the ammonia diffusion uniform. To provide an ammonia injection device capable of improving the denitration rate by promoting the above. [0006] Means for Solving the Problems] ammonia injection apparatus according to the present invention, the ammonia injection pipes constituting this
A number of injection nozzles are opened at equal intervals on both sides in the gas flow direction.
And each nozzle in the pipe
During, vital how such a predetermined angle of inclination with respect to the gas flow direction
A flange-like fin having a shape contour is provided. In the ammonia gas injection device having the above configuration,
The installation of a plurality of flange-like inclined fins of the ammonia injection pipe can generate regularly controlled vortices in the exhaust gas, which can increase the gas diffusion rate. Since the vortex is generated regularly, the entire gas flow is not biased. [0009] By increasing the diffusion rate in this manner, the distance between the ammonia injection grid and the denitration catalyst can be shortened, the interval between the plurality of injection grid pipes can be widened, the grid configuration can be simplified, and the ammonia diffusion can be made uniform. And the denitration rate can be improved. Embodiments of the present invention will be specifically described below with reference to the illustrated embodiments. The ammonia injection grid (1) is composed of a frame, a plurality of ammonia injection pipes (2) passed over the opposite part of the frame, and a plurality of supports for supporting the pipe (2) on the frame. A number of injection nozzles (4) are opened at equal intervals on both sides in the gas flow direction of the ammonia injection pipe (2). The ammonia injection pipe (2) is provided with a plurality of fins (3) as shown in FIG. The fin (3) is a flange having a rectangular contour.
Therefore, they are arranged between the nozzles (4), and are inclined at a predetermined angle (θ) with respect to the gas flow direction. Ammonia injection grid (1) having the above structure
Are arranged in the exhaust heat recovery boiler (24) in the exhaust gas outlet duct (23), as shown in FIG. The exhaust gas is an ammonia injection grid.
After passing through (1), a vertical vortex (5) is formed in the wake direction from the end of each fin (3), as shown in FIGS.
The vaporized ammonia gas emitted from the ammonia injection nozzle (4) is mixed with the exhaust gas and introduced into the formed vertical vortex (5).
Each of these vortices (5) extends regularly in the wake direction from the tip of each fin (3) and has the same rotational direction. Therefore, the flow of the entire exhaust gas is not deviated in one direction, and the diffusion of the injected ammonia does not become uneven. Then, due to the formation of the vortex, the ammonia gas diffuses uniformly in the exhaust gas at a much higher speed, for example, 5 to 10 times as fast as that in the normal uniform flow. According to the present invention, as described above, the generation of the vortex disturbs the flow of the exhaust gas, thereby promoting the diffusion of the ammonia gas in the exhaust gas. As a result, it is possible to reduce the distance between the ammonia injection grid and the catalyst packed bed of the denitration device. In addition, this effect can increase the interval between each ammonia injection pipe, that is, reduce the number of the pipes, simplify the configuration of the injection grid, further promote uniform ammonia diffusion, and improve the denitration rate. Can be done.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (a) is a perspective view showing an ammonia injection grid according to the present invention. FIG. 1B is a side view of the ammonia injection grid. FIG. 1C is a front view of the ammonia injection grid. FIG. 2 is a vertical sectional view showing a denitration apparatus. FIG. 3 is a front view showing a conventional ammonia injection grid. FIG. 4 is a perspective view showing a conventional ammonia injection pipe. [Description of Signs] 1: Ammonia injection grid 2: Ammonia injection pipe 3: Fin 4: Nozzle 5: Longitudinal vortex

Continued on the front page (72) Inventor Emiko Higashi 5-3-28 Nishikujo, Konohana-ku, Osaka-shi Inside Tachibashi Shipbuilding Co., Ltd. 31 (56) References JP-A-59-176635 (JP, U) JP-A-7-9428 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01D 53 / 56,53 / 86

Claims (1)

(57) [Claim 1] A large number of injections are provided on both sides in the gas flow direction of an ammonia injection pipe constituting an ammonia injection grid.
Nozzles are opened at equal intervals and the pipe
Each between nozzles, the ammonia gas injection device in denitrator flanged Fi <br/> down is provided with a contour of the life-and-death square such a predetermined angle of inclination with respect to the gas flow direction in the.