Distillation trays efficiency, reduction

Pressure Tray efficiency slightly increases with pressure (Fig. 14-43), reflecting the rise of efficiency with a reduction in liquid viscosity and in relative volatility, which generally accompany a distillation pressure increase. 

Flooding In distillation, the point in the operation where increases in vapor-liquid loading cause a noticeable reduction in the fractionation efficiency or tray efficiency of the tower. 

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