Vortex mixing device for SCR (silicon controlled rectification) flue gas denitration system

The invention discloses a vortex mixing device of an SCR (silicon controlled rectification) flue gas denitration system. The uniformity of the flue gas speed of a conventional boiler denitration system can be guaranteed, but as the uniformity of NH3 concentration is low, the denitration efficiency is low, and as NH3 is not uniformly distributed, the NOx removal rate in a relatively diluted region is low while the escape amount of ammonia in a relatively concentrated region is large. The vortex mixing device comprises an ammonia spraying pipeline (4) which is arranged in a rising pipeline of an economizer outlet flue (1); a group of ammonia sprayers are arranged on the ammonia spraying pipeline; the ammonia spraying pipeline is connected with an ammonia spraying flue (6); a vortex mixer group (5) is arranged in the ammonia spraying flue; the ammonia spraying flue is communicated with a catalyst flue with catalysts; a diversion blade is arranged at an inlet of the catalyst flue; a rectification grid is arranged on the upper part of the catalyst flue. The vortex mixing device is used for controlling emission of nitric oxides in flue gas generated from thermal power generation.