Middle vessel heterogeneous batch distillation of an azeotropic mixture

Abstract

This chapter discusses the operation of heterogeneous batch distillation (HBD) in a middle vessel column (MVC). A feasibility analysis is attempted and simulations are carried out, which demonstrates the advantage of MVC compared to regular and inverted columns. HBD synthesis differs significantly from homogeneous batch distillation synthesis. Some advantages of HBD processes compared to homogeneous systems are more design alternatives for the separation of nonideal mixtures, simplified distillation sequences because of less distillation, addition of less entrainer, crossing of batch distillation boundaries because of a flexible reflux policy that enables to reflux to the column a mixture different from the distillate through any combination of the entrainer-rich phase and the distillate-rich phase. A complete set of rules for the selection of both homogeneous and heterogeneous entrainers for the separation of minimum or maximum temperature azeotropic binary mixtures is determined. The feasibility of the separation of the water-acetonitrile-acrylonitrile-acetic acid mixture by simulating HBD process is discussed.