Efficient optimization-based design for the separation of heterogeneous azeotropic mixtures

Conceptual Design of Azeotropic Distillation Processes

“…The solution of the equilibrium problem including a phase stability test as a subproblem has been shown to improve the robustness of the solution algorithms in dynamic simulation [128]. This computational strategy has been shown to improve robustness also in rigorous design optimization [129].…”

“…The total energy demand of the separation system is 700 kW, only slightly above the MED estimated by the shortcut method. The recycle flowrate of the cost-optimal design [129]. Figure 8.22 provides an overview on the optimized flowsheet.…”

A unifying framework for optimization-based design of integrated reaction–separation processes

“…Thus, a local solution of the MINLP can be found by a sequence of a few NLPs with gradually tightened bounds. Additionally, external functions (Skiborowski et al, 2015) are added to GAMS (Brooke et al, 2005) to accomplish vapor-liquid equilibrium (VLE) calculations and to provide the associated gradient information. Since the external functions are implemented in a DLL, in the programming language according to the requirements of GAMS, there is some overhead for communication, but the robustness of the optimization problem is increased significantly (Skiborowski et al, 2015).…”

“…Additionally, external functions (Skiborowski et al, 2015) are added to GAMS (Brooke et al, 2005) to accomplish vapor-liquid equilibrium (VLE) calculations and to provide the associated gradient information. Since the external functions are implemented in a DLL, in the programming language according to the requirements of GAMS, there is some overhead for communication, but the robustness of the optimization problem is increased significantly (Skiborowski et al, 2015). Although the reformulation of the optimization problem by means of NCC and the utilization of external functions improve the robustness of the optimization runs, still a suitable initialization procedure is necessary to provide a feasible starting point.…”

Outer approximation algorithm with physical domain reduction for computer‐aided molecular and separation process design

“…Another recently proposed strategy to deal with model discontinuities arising from a change in the number of phases is to carry out phase stability and equilibrium calculations for each stage via an external function. 20 The effective handling of these implicit constraints remains an active area of research.…”