From problem specification to converged flowsheet simulations: Integrated workflow in an industrial context

Although distillation is considered the most mature and computationally easiest to analyze and optimize fluid separation process, support for flowsheet synthesis for the separation of multicomponent azeotropic mixtures is still limited. Commercial simulation software like Aspen Plus mainly offers a graphical analysis of residue curve maps for ternary (sub)systems or an iterative evaluation based on tedious simulation studies. The current work presents an integrative algorithmic approach that pursues an automatic synthesis of distillation processes for azeotropic mixtures, building on a topological analysis of the distillation regions and evaluation of residue curves, pinch lines, and rectification bodies. The derived flowsheet structures and the estimated minimum reflux ratios are the basis for optimization-based initialization of rigorous column models and full-scale simulations of the integrated flowsheets in the industrial in-house simulation tool Chemasim. Thus, the method provides an algorithmic fast-track from a thermo-dynamic mixture model to a rigorous simulation of automatically derived flowsheets.