EFFECT OF COPPER CONTENTS OIL SULFUR POISONING OF COPPER ION-EXCHANGED MORDENITE FOR NO REDUCTION BY NH3

Deactivation of copper ion-exchanged mordenite (CuHM) catalysts with d ifferent copper contents by SO2 for NO reduction with NH3 was examined in a fixed bed flow reactor. A larger amount of deactivating agent de posits on the catalyst surface with the increase of copper contents un der the same operating conditions. The deactivating agents deposited o n the copper-exchanged mordenite catalysts were mainly (NH4)(2)SO4 and /or NH4HSO4 from the results of thermal analyses such as thermogravime tric analysis (TGA), differential thermal analysis (DTA), and temperat ure-programmed desorption (TPD). The formation of the ammonium salts l argely depends on the reaction temperature and SO3 concentration gener ated from SO2 oxidation which is a reaction catalyzed primarily by cop per ions on the catalyst surface. The catalytic activity and surface a rea of the deactivated catalysts are well-correlated with the sulfur c ontent deposited on the catalyst surface, depending upon the reaction temperatures and its catalyst copper contents.