(756g) Optimization of Distillation Column and Separation System Design

Distillation columns have traditionally been modelled using a sequential modular simulation approach. While well-established, the approach brings numerous challenges, particularly where highly-integrated systems involving heat and material recycles are involved.  On the other hand, users of the more powerful equation-oriented approach have traditionally struggled with the difficulty of obtaining an initial solution.

 This presentation describes how new model initialization techniques significantly simplify distillation modelling in equation-oriented software. This allows not only much more rapid solution, allowing sensitivity studies on complex separation systems, but also opens the door to large-scale optimization calculations involving both continuous and integer decisions (the latter, for example, including feed tray location and number of stages decisions), including whole-plant optimisation of separation sections simultaneously with reactors. The paper is illustrated with simulation of an air separation unit, among other examples.