Synthesis of Distillation Column Sequences for Nonsharp Separations

In this paper an algorithm to generate all possible distillation Column sequences for a nonsharp separation of c components to m multicomponent as well as pure desired products, based on the product specifications, is presented. Each desired product is defined by the minimum and maximum acceptable values of product rates as well as the concentration of each component. The possible sequences are generated by the introduction of a separation matrix. In the proposed algorithm each sequence can include between 1 and c - 1 simple and/or complex distillation columns and bypass streams. The sequences with less than c - 1 distillation Columns can be generated systematically by the proposed algorithm. Also, a design strategy has been proposed for the optimization of the sequences. This algorithm has been used for a nonsharp separation example. A sequence with less than c - 1 number of distillation columns and bypass streams is selected as the optimum structure for this example. This Optimum sequence can cause significant savings of up to 22% in TAC relative to the traditional sequences with simple distillation columns.