CATALYTIC COMBUSTION TECHNOLOGY TO ACHIEVE ULTRA-LOW NOX EMISSIONS - CATALYST DESIGN AND PERFORMANCE-CHARACTERISTICS

A catalytic combustion system has been developed which feeds full fuel and air to the catalyst but avoids exposure of the catalyst to the hi gh temperatures responsible for deactivation and thermal shock fractur e of the supporting substrate. The combustion process is initiated by the catalyst and is completed by homogeneous combustion in the post ca talyst region where the highest temperatures are obtained. Catalysts h ave been demonstrated that operate at inlet temperatures as low as 320 degrees C at 11 atm total pressure and conditions typical of high per formance industrial gas turbines. The ignition temperature is shown to correlate with the specific catalytic activity of the washcoat layer over a rather broad range of activities. A reaction model has been dev eloped that can predict ignition behavior from the measured catalytic activity.