APPARATUS AND METHOD FOR DENITRIFYING STACK GAS

PROBLEM TO BE SOLVED: To provide an apparatus and a method for denitrifying stack gas, in which the flow rate of ammonia to optimize the denitrification performance and the flow velocity distribution of combustion gas can be adjusted. SOLUTION: When a gas concentration sensor 12 measures the ammonia concentration in a gaseous mixture, a control part acquires the measured ammonia concentration, estimates the flow velocity distribution of the combustion gas on the upstream side of an ammonia injecting nozzle 11 on the basis of the measured ammonia concentration, calculates the flow rate of the ammonia to optimize the denitrification performance on the basis of the estimated flow velocity distribution of the combustion gas and instructs a regulating valve to inject the ammonia of the calculated flow rate. For example, when the flow velocity distribution is large, the control part instructs the regulating valve to lower the flow rate of the ammonia to be injected. COPYRIGHT: (C)2004,JPO