Why VDU has larger diameter and shorter height as compared to ADU ?

Question

Accepted Answer

VDU has larger diameter and shorter height to facilitate better separation of heavier and lighter components.

VDU stands for Vacuum Distillation Unit and ADU stands for Atmospheric Distillation Unit.
VDU operates under vacuum conditions to reduce the boiling point of crude oil components.
The larger diameter of VDU allows for a larger surface area for vaporization and condensation.
The shorter height of VDU allows for better separation of heavier and lighter components due to the reduced distance for vapor to travel.
ADU operates under atmospheric pressure and has a taller column to facilitate separation of components with higher boiling points.
The design of VDU and ADU depends on the properties of the crude oil being processed.

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