Method for controlling NOx removal system in boiler

摘要

A method for controlling a NOx removal system in which reductant supply is adjusted according to combustion level in a boiler (1) in which the combustion level is controlled in multiple stages. For a decrease of the combustion level, the reductant supply is kept lower than a level corresponding to a changeover-target combustion level for a period of a set time from the changeover of the combustion level. Thus, when the reductant supply is changed over in response to a changeover of combustion level, the reductant can be prevented from flowing outside as it is unreacted.