Method of purifying combustion fumes containing nitrogen oxides

摘要

The method involves supplying combustion fumes (1) to a nitrogen oxide removal catalyzer (3). A retention time of combustion fumes ad temperature are regulated, between urea injection point and contact set point of the fumes, so that the ammonia destruction reaction of the isocyanic acid that is risen from a urea decomposition is incomplete, when the fumes contact with a catalyzer, for reacting the acid with a nitrogen oxides in the presence of the catalyzer to reduce the state of nitrogen.