re: Operators....how long did it take to qualify

My refinery requires a minimum of 6 months in a unit before you can take it alone. You have a full year to meet those requirements.
We try to start new operators in larger or more complex units because your maximum time to qualify in each unit becomes less and less as you get your promotions and pay raises.
Some units are harder than others.
If your learning utilities and you have to learn all phases of the process it can take the full 6 months.
If you have cooling towers, boilers, Co-gens, air compressors, De-alks, softeners, etc. You should expect it to take a bit.
Remember that the utilities are the heart of the refinery and you have to know what to do in a outage without hesitation. For this reason we normally don't start new operators in our utility section.
Good luck