METHOD FOR INJECTING AMMONIA IN COMBUSTION GAS AND APPARATUS THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a method for a capable of injecting ammonia responding to a SO3 concentration distribution in exhaust gas of a boiler, and an apparatus therefor. SOLUTION: The method is for injecting ammonia in a combustion gas in the upstream side of an electric dust collector to neutralize the SO3 gas in the exhaust gas and remove it by the electric dust collector and involves steps of installing a plurality of spraying nozzles 13 for injecting ammonia in up and down and right and left sides of a duct cross-section 10A of the exhaust gas duct 10 in the upstream side of the electric dust collector, installing a plurality of combustion gas sampling pipes 22 corresponding to the spraying nozzles 13 in the upstream side or the downstream side of the spraying nozzles 13 in the exhaust gas duct 10, measuring the SO3 concentration distribution in the direction of the duct cross-sectional face 10B by introducing the combustion exhaust gas sampled by the respective exhaust gas sampling pipes 22 into a continuous SO3 concentration analyzer 26, and controlling the injection amounts of ammonia to be sprayed out of the spraying nozzles 13 on the basis of the measured SO3 concentration distribution in the direction of the duct cross-section 10B, respectively.