Feasible separations and entrainer selection rules for heteroazeotropic batch distillation

Heterogeneous extractive batch distillation of chloroform–methanol–water: Feasibility and experiments

“…Non ideal mixtures separation overall performance heavily relies on the choice of a suitable entrainer E. This issue has been frequently considered for a non ideal binary mixture A-B separation under continuous operation (Berg, 1969;Doherty and Caldarola, 1985;Laroche et al, 1991Laroche et al, , 1992Pöllmann and Blass, 1994;Perry et al, 1997) or under batch operation (Lang et al, 1994;Safrit et al, 1995;Lelkes, 1998;Rodriguez-Donis et al, 2001a,b, 2003aSkouras et al, 2005;Gerbaud et al, 2006;Kotai et al, 2007). Apart from being market available, inexpensive, stable, non toxic, non-flammable or non corrosive, the most awaited feature of the entrainer E is selectivity, through preferential interaction with either A or B.…”

Heterogeneous batch distillation processes: Real system optimisation

“…Validation on case study one (a double task single rectifier heterogeneous batch process for the separation of Water-Pyridine with Toluene) with five optimisation variables shows that the use of GA followed by an SQP is the recommended choice. Validation on case study two (a two homogeneous batch distillation column sequence for the separation of Methyl Acetate -Chloroform with Benzene) demonstrates the capability of the optimisation framework to handle sequential different sets of differential algebraic equation sets, thus showing that it is readily suited for the optimisation of the novel batch distillation processes described in the literature (Rodriguez-Donis et al, 2001a, 2001b, 2002Modla et al, 2003, Skouras et al, 2005b.…”

“…So this sequence does effectively split the binary azeotrope Methyl Acetate -Chloroform but the recovery yield is not optimum. Other processes with other kind of entrainer exist with better separation efficiency (Rodriguez-Donis et al, 2001a, 2001b, Skouras et al, 2005b. The expected still and distillation paths are illustrated on figure 4.…”

“…According the Rodriguez-Donis et al (2002) and Skouras (2004Skouras ( , 2005b, the separation is possible using a heterogeneous entrainer. Toluene (intermediate boiling, non-selective entrainer) is added to the mixture, forming a minimum temperature homoazeotrope with Pyridine and a minimum 11/46 temperature heteroazeotrope with Water.…”

“…For azeotropic or close-boiling mixtures, the addition of an entrainer, partially or totally miscible with one of the initial binary mixture components, is viable and its choice is the first key issue of azeotropic batch distillation. A whole set of entrainer selection rules has been published for both homogeneous and heterogeneous azeotropic distillation for the separation of azeotropic binary mixtures or close boiling components (Rodríguez Donis et al, 2001aand 2001b, Skouras et al, 2005b. These rules also hint at a feasible sequence of batch column needed to perform the separation together with the initial feed stream location in the ternary diagram.…”