Here is update on the two COP Billings Coke Drum replacements from when they arrived in July Megaload movement news update. This article mentions a 30 year life that is almost never reached because operating cokers never run at design rates of 24 hour cycles which is why planning stage starts in 20 year life as min many are replaced in 10-15 year life due heavier than designed crudes and 9-12 hour coker cycles which reach ~5000 cycles per coker drum life in about half 20-30 year design.
Here is hoping that COP doesnt have problems with the giant crane that has plagued other refinery projects (Crane industry doesnt require license or impose standards on operators see prior post on this safety item).
Regards