There are several factors that contribute to ammonia slip:
1. Ammonia Overdosing: Introducing more ammonia than required for the NOx reduction can result in excess unreacted ammonia. 2. Temperature Deviations: The SCR reaction is temperature-sensitive, and deviations from the optimal range (typically 250-400°C) can lead to incomplete reactions. 3. Catalyst Deactivation: Over time, the catalyst may lose its activity due to poisoning, sintering, or fouling, reducing its efficiency in converting ammonia and NOx. 4. Poor Mixing: Inadequate mixing of the ammonia with the exhaust gases can result in uneven reaction zones, leaving pockets of unreacted ammonia.
