The difference in cost between plate and packed columns is not too great, although packings are generally more expensive than plates.
In addition, the difference in column height is not usually significant if the flow rates are such that efficiencies are near maximum.
Conditions favouring packed columns:
Small-diameter columns (less than 0.6m)
More choices in materials of construction for packings especially in corrosive service (e.g. plastic, ceramic, metal alloys)
Lower pressure drop (important in vacuum distillation)
Less liquid entrainment · low liquid hold-up, especially suitable for thermally sensitive material
Foaming liquids can be handled more readily (less agitation of liquid by the vapour)