High AT in transfer line beetween heater and drum.
After a maintenance shut down of the unit where we have some modifications in this pipe, the AT between heater and drum has increased from 18ºC until 27ºC (average values). We process heavy crudes with a 25%w concarbon and 20% C7 asphaltene.
For this crude, which is the minimum inlet drum T in order to avoid problems with coke formation? (Our current minimal T is around 468ºC)
Which is the maximum coil outlet T to avoid aceletated fouling in the heater? (now we would need to increase up to 500ºC)
We use fierglass insulation in this pipe. Have you tested any better insulation (e.g. aerogel)?
We are thinking to try an electric heat tracing, do you have any reference of this option being used in delayed cokers? Would it cause fouling in the pipe?