Steam temperature consideration for column operating under vacuum

  1. 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.
diagram, engineering drawing

Written by: Rajesh Pingale 

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