We have NOx catalysts on our gas turbines (7FA and LM6000) and are familiar with their maintenance and service requirements. The 7FA is over 90,000 hours with one cleaning, while the LM6000’s have 20,000 hours with 3 cleanings to date. None have been replaced. A HUG field engineer was onsite earlier this week to inspect one of our SCR’s on a 18V50SG and commented that in addition to the recommended 4000 hour cleaning, the service life was expected to be in the 12,000-15,000 hour range. This came as a shock to us given the long life we’ve seen with gas turbine SCR’s. What is the typical lifespan of the HUG catalyst blocks in your experience? We also have a pair of 20V34SG units, so please chime in if you have data on them as well.