- Operating a column under vacuum is typically for following scenarios
1. Low temperature constraint due to Heat sensitive material
2. Lowering of high boiling component boiling point
Learning:
So, while operating a column under vacuum with vertical thermosiphon reboiler one should carefully decide steam temperature and pressure required at reboiler inlet flange-based process side conditions and not at column bottom flange.
Suggestion:
The Process side temperature at reboiler flange inlet will always be higher than column bottom temperature due to additional static head based on thermosiphon requirement which will have a direct impact on steam temperature and pressure requirement.
Take into consideration the above point when finalizing the utility conditions for plant.
Written by: Rajesh Pingale