Separation of highly non-ideal quaternary mixtures with extractive heterogeneous-azeotropic distillation

To design suitable, generally applicable separation schemes and to conclude a design strategy, the separation of highly non-ideal quaternary mixtures, containing both heterogeneous and homogeneous minimum boiling azeotropes, is studied. The separation schemes are based on our novel distillation technique, the extractive heterogeneous-azeotropic distillation (EHAD) that simplifies the separation schemes significantly. To determine generally applicable separation schemes based on the EHAD, the separation of eight quaternary mixtures, usually waste streams of different industries, classified into four groups is studied. Since water is always present in the mixtures investigated, it is used in each separation alternatives as auto separating agent and/or entrainer. The visualization of the vapour-liquid-liquid equilibrium and the separation of the quaternary mixtures are also solved. The core of the different novel separation schemes designed is the EHAD and it is always verified experimentally in a laboratory size column. The recommended strategy for the separation of different quaternary mixtures, containing both homogeneous and heterogeneous azeotropes, proves to be successful.