Selective non-catalytic reduction (SNCR) denitration multi-nozzle long-gun injector

The invention relates to a selective non-catalytic reduction (SNCR) denitration multi-nozzle long-gun injector, which comprises a gun body assembly and at least two nozzles, wherein the gun body assembly comprises a pipeline assembly, an input assembly and a gun head; the pipeline assembly comprises a cooling water input pipe, a urea pipe, an air pipe and a cooling water output pipe from the interior to the exterior in turn; the input assembly comprises a water inlet joint, a urea joint, an air joint and a water outlet joint; the gun head comprises a urea seal head, an air seal head which is arranged at an outlet end of the air pipe, and a cooling water seal head which is arranged between an inlet end and a cooling water outlet end of the cooling water output pipe; each nozzle is an internal-mixing nozzle arranged on the gun assembly; a mixing chamber of each nozzle is communicated with a urea cavity and an air cavity respectively; and an opening of each nozzle is formed on a side wall of the cooling water output pipe. The technical problem that the conventional SNCR denitration multi-nozzle long-gun injector is low in denitration efficiency and unstable in performance in a high-temperature high-corrosion and high-abrasion flue gas environment is solved, and the injector is reasonable in design, stable in operation and high in denitration efficiency.