| 摘要 |
In the flue-gas duct of a power station, it is customary to feed the ammonia necessary for the catalytic decomposition of oxides of nitrogen into the flue gases through a multiplicity of feed pipes and nozzles, and through the same number of valves to be adjusted, so that the ammonia is homogeneously distributed throughout the flue gases. The pressure drop produced by equipment of this kind in the flue-gas duct is relatively high, however, and the equipment itself is relatively complex and costly. In order to overcome these disadvantages, the invention proposes a combined feed and mixing installation (14, 36) designed to feed a first fluid medium (M1), e.g. ammonia, into a second fluid medium (M2), e.g. flue gases (28) containing oxides of nitrogen, conveyed by a duct (4) and to mix the two fluid media (M1, M2). The installation includes at least one pipe conveying the first fluid medium (M1), with at least one feed port (22), and a mixing unit (26, 26a to 26h). Relative to the cross-sectional area A and the hydraulic diameter ddydr. of the duct (4), the installation has 0.05 to 10 feed ports (22) per square metre of the cross-sectional area A. The distance a between each feed port (22) and the mixing unit (26, 26a to 26h) is between 0.05 and 3 times dhydr.. This ensures that the ammonia is fed in and mixed with the flue gases homogeneously (Fig. 2).
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