Efficient optimization-based design for the separation of heterogeneous azeotropic mixtures. (2nd January 2015)

• Record Type: Journal Article
• Authors: Skiborowski, Mirko; Harwardt, Andreas; Marquardt, Wolfgang
• Is Part Of: Computers & chemical engineering. Volume 72(2015)
• Page Start: 34
• Page End: 51
• Publication Date: 2015-01-02
• Subjects: Heteroazeotropic distillation -- Superstructure optimization -- Phase stability test -- Process design; Chemical engineering -- Data processing -- Periodicals; 660.0285
• DOI: 10.1016/j.compchemeng.2014.03.012
• Languages: English
• ISSNs: 0098-1354

Abstract

Abstract : Graphical abstract: Abstract : Highlights: Deterministic optimization-based design of heteroazeotropic distillation processes. Model reformulation for simple and heteroazeotropic distillation columns. External function integrates phase stability test for reliable equilibrium calculations. Simultaneous optimization of operational and structural design degrees of freedom. Application to several case studies of various complexity. Abstract: Model-based design of separation processes for heterogeneous azeotropic mixtures is a challenging task. The multiplicity of the solutions of equilibrium calculations and the discontinuity due to the potential switching between homogeneous and heterogeneous mixtures on a tray severely complicate the application of deterministic optimization. This paper presents a novel computational approach to reliably determine phase stability and the correct equilibrium solutions in every iteration of the optimization. The approach builds on the decomposition of the optimization problem into a generic superstructure model and an implicit model for equilibrium and enthalpy calculations, which is integrated into the optimization problem by means of an external function. The phase states and equilibrium solutions are determined by means of a reliable homotopy continuation algorithm. An additional reformulation of equilibrium solutions and enthalpy calculations allows overcoming the discontinuity problems. Different case studies illustrate the applicability and show the potential of the proposed method.