Design and optimization of hybrid separation processes

Hybrid separation processes are defined as the combination of at least two different unit operations in different apparatus which contribute to the separation task. Hybrid processes are used for difficult separations, e.g., close-boiling mixtures and azeotropes, if a single unit operation, e.g., distillation, membranes, extraction, crystallization or chromatography, is not efficient or even not feasible. Because of the structure of a hybrid process which implies two or more unit operations and recycle streams, the design is not straightforward and therefore subject of today's research. in this work general criteria for such a consistent design method are described and a design approach for hybrid separation processes is presented. It bases on rigorous modeling of the unit operations and simultaneous multivariable optimization. The approach feasibility is demonstrated by the separation of an isomer mixture.