To provide a method for reducing discharge of ammonium in combustion exhaust gas and other waste flow by using oxidizing catalysts (21, 31).
In this method, the amount of gaseous contaminant other than ammonium is reduced, and the amount of unreacted ammonium (ammonium "slip") is reduced on the downstream side of a selection contact reduction "SCR" systems (23, 33). Under a condition in which oxygen is present, noble metal-based catalyst such as Pt, Pd and Ru is used so that ammonium is oxidized, and a species becomes a kind of higher oxidized state of nitrogen, preferably, nitrogen element N2. The efficiency of the process can be improved by optimizing the operational condition of the catalyst, and adjusting the temperature and the space velocity of the noble metal-based catalyst and the position with respect to the SCR systems (23, 33).
ZAMANSKY VLADIMIR
SEEKER WILLIAM R
ENGLAND GLENN C
Hirokazu Ogura
Nobukazu Ito
Toshihisa Kurokawa