Ammonia gas SNCR denitration system for tower-type boiler

The invention provides an ammonia SNCR denitration system for a tower type boiler, belongs to the field of environment-friendly denitration, and aims to solve the problems of tube explosion of a superheater, ammonia escape and influence on the boiler efficiency caused by shortening of effective reaction time in conventional reduction reaction. An air inlet of an ammonia conveying pipeline is connected with an ammonia pipeline, and an air outlet is connected with an air inlet of an ammonia-air mixer; an air inlet of a dilution fan is connected with an air pipeline, and an air outlet is connected with an air inlet of an air conveying pipeline; an air outlet of the air conveying pipeline is connected with an air inlet of the ammonia-air mixer, an ammonia spraying grid device is arranged between a third-level superheater and a fourth-level superheater of a tower-type boiler, an air outlet of the ammonia-air mixer is connected with an air inlet of a first valve, and an air outlet of the first valve is connected wi