Determination of number of stages in divided wall column for cryogenic distillation of air

Air separation is an important industrial gas separation process. The separation is accomplished by both cryogenic and non-cryogenic methods. The cryogenic air separation can give high purity of gases (nitrogen, oxygen, and argon). To reduce the capital cost by maintaining high purity of the product gases, divided wall column (DWC) has been proposed for gas separation. The same technique has also been used for air separation. However, there is no studies on the designing of divided wall column for air separation. In this work, we present a modelling strategy to design a DWC for air separation. The strategy involves the use of the Naphtali-Sandholm method that has been developed for the design of a conventional distillation column. (author)