For Humboldt Bay our first ammonia slip catalyst went bad 5 years after commissioning and approximately 21650 on the engine. We find that the number of starts affects the failure time quite a bit. And of course, operating temperature. Even though we operated below the high temperature we found the catalyst degrades rapidly at the higher temperatures.
The sequence of events is as follows – ammonia slip fails first. Followed shortly by the CO catalyst – however, a row of CO catalyst can be added to bring emissions back into control.
The SCR catalyst fails next and a row is added to regain emissions.
I’d be happy to discuss via phone if you’d like – 707 441 2667.