Design of Hybrid Distillation/Melt Crystallization Processes for Separation of Close‐Boiling Mixtures

Abstract

Die Kombination aus Rektifikation und Schmelzekristallisation in einem hybriden Trennverfahren hat großes Potenzial für die Prozessintensivierung. Allerdings stellt die Auslegung solcher Verfahren aufgrund der Vielzahl struktureller und operativer Freiheitsgrade eine große Herausforderung dar. Für die Auslegung hybrider Trennverfahren hat sich eine dreistufige Auslegungsmethode durchgesetzt, die aber nur dann angewendet werden kann, wenn alle Modellparameter für die Kristallisation a priori bekannt sind. Da dies oft nicht der Fall ist, wird hier eine vierstufige Entwurfsmethode vorgeschlagen. Die Eignung der Methode sowie entwickelte Werkzeuge werden an einem Fallbeispiel der Trennung langkettiger isomerer Aldehyde vorgestellt.

Process Modeling, Simulation and Optimization: From Single Solutions to a Multitude of Solutions to Support Decision Making

“…Also, evolutionary algorithms (EA) are used in this context. Micovic et al used an EA for the design of a hybrid separation based on distillation columns and melt crystallization. Skiborowski et al used a combination of an EA and deterministic optimization for the design of different distillation processes.…”

“…Sometimes in case of missing information about physical properties to evaluate a concept, it is possible to estimate the parameters which would be necessary to make a process variant attractive and then to trigger subsequent testing of promising candidates. Examples of such methods are used for membranes (Micovic et al , Scharzec et al ) or solvent selections using continuous‐molecular targeting for integrated solvent and process design (Bardow et al , Stavrou et al , Austin et al ).…”

Modeling, Simulation, and Optimization 4.0 for a Distillation Column

“…Hybrid systems as an opportunity for process intensification are discussed since more than 30 years: Examples are reactive distillation , combinations of distillation with vapor permeation or pervaporation (e.g., ), reactive distillation with pervaporation , melt crystallization , or combinations with dividing wall columns like reactive, azeotropic or extractive DWC .…”

Modeling Growth Rates in Static Layer Melt Crystallization

“…Layer melt crystallization is a highly selective and technically proven method for separating the components of organic mixtures, whereby the purified substance crystallizes on a cooled surface. − This method has gained significance over the last several decades, especially for separating azeotropic mixtures or isomers with similar boiling points. − Layer melt crystallization can be divided into dynamic and static processes. In the dynamic case, the melt is mixed by forced convection caused by stirring or pumping, whereas a mixing of the melt in the static case is induced by natural convection. − In both cases, crystal purity depends significantly on the crystal growth rate, despite the thermodynamic solid–liquid equilibrium .…”