CATALYTIC REDUCTION OF NITRIC OXIDE IN NET OXIDIZING ENVIRONMENTS

NITROGEN OXIDES (NO AND NO2 OR NOX) ARE AMONG THE MOST PERVASIVE AND DIFFICULT EMISSIONS TO CONTROL. ALTHOUGH THE DECOMPOSITION OF THE MAJOR SPECIES (NO) IS THERMODYNAMICALLYFAVORED, THERE ARE NO CATALYTIC PROCESSES CAPABLE OF DECOMPOSING NOX WITHOUT THE ADDITION OF A REDUCING GAS. THIS IS BECAUSE THE OXYGEN PRODUCED DURING THE DECOMPOSITIONREMAINS STRONGLY CHEMISORBED ON THE CATALYST, BLOCKING ACCESS OF THE NO TO THE CATALYTIC SITES AND REVERSIBLY POISONING THE CATALYST. BECAUSE THE REDUCING GAS CONTRIBUTES ROUGHLY ONE-HALF OF THE TOTAL CLEANUP COST, A DIRECT CATALYTIC DECOMPOSITION PROCESS WHICH DID NOT REQUIRETHE USE OF A REDUCING GAS WOULD BE A MAJOR ADVANCE. TDA RESEARCH, INC., (TDA) PROPOSES TO DEVELOP SUBSTITUTE ZEOLITES CAPABLE OF CARRYING OUT THIS REACTION. THESE MATERIALS DESORB THE OXYGEN AT A LOWER TEMPERATURE THAN DO OTHER MATERIALS, ALLOWING THE REACTION TO PROCEED. TDA WILLSYNTHESIZE SUBSTITUTE ZEOLITES AND EVALUATE THE PERFORMANCE OF THESE MATERIALS UNDER CONDITIONS REPRESENTATIVE OF THE EXHAUST OF A GAS TURBINE. THEN TDA WILL DEVELOP IMPROVED CATALYSTS THROUGH MANIPULATION OF BOTH THE STRUCTURE AND COMPOSITION OF THE ZEOLITE, AS WELL AS THE CATALYTICALLY ACTIVE CATIONS.