ANALYSIS OF A MEMBRANE DISTILLATION COLUMN HYBRID PROCESS

Distillation of low relative volatility mixtures is highly energy inte nsive and can require tray numbers greater than 150. Two design method s for a hybrid process are given to minimize the trav number in a dist illation column that contains a membrane unit: the minimum area method and the Smoker's equation method. The Smoker's equation method is use d to study the effect of different membrane variables on the tray numb er. The optimal position of the membrane unit on the distillation colu mn is close to the feed to the distillation column. The number of tray s in the distillation column does not decrease indefinitely with an in crease in the membrane surface area due to the decreased selectivity. Maximum reduction in tray number of the distillation column occurs whe n the ratio of the membrane feed rate to the membrane area is close to 0.1 mol/m2 s. An analytical expression for optimal placement of a mem brane unit on a distillation column is given for a special case using the minimum area method. Finally, simulations were performed to prove that both methods are equally valid.