11.5. DISTILLATION AND ABSORPTION EFFICIENCIES FOR TRAY AND PACKED TOWERS
11.5A. Tray Efficiencies
In all the previous discussions of theoretical trays or stages in distillation, we assumed that the vapor leaving a tray was in equilibrium with the liquid leaving. However, if the time of contact and the degree of mixing on the tray are insufficient, the streams will not be in equilibrium. As a result the efficiency of the stage or tray will not be 100%. This means that we must use more actual trays for a given separation than the theoretical number of trays determined by calculation. The discussions in this section apply to both absorption and distillation tray towers.
Three types of tray or plate efficiency are used: overall tray efficiency E ...