Thermodynamic Insights on the Feasibility of Homogeneous Batch Extractive Distillation. 3. Azeotropic Mixtures with Light Boiling Entrainer

Ivonne Rodríguez-Donis (1) , Vincent Gerbaud (2) , Xavier Joulia (2)

1 Instituto Superior de Tecnologías y Ciencias Aplicadas - INSTEC (La Havana, Cuba)
2 LGC - Laboratoire de Génie Chimique

This article shows how knowledge of the location of univolatility lines and residue curve analysis helps in assessing the feasibility of extractive distillation of minimum-boiling (minT) or maximum-boiling (maxT) azeotropic mixtures or low-relative volatility (low-α) mixtures (A-B) by using a light-boiling entrainer (E), in accordance with the general feasibility criterion of Rodriguez-Donis et al. [Ind. Eng. Chem. Res. 2009, 48 (7), 3544-3559]. Considering all possible locations of the univolatility line αAB, three minT azeotropic mixtures with a light entrainer (1.0-2 class), namely, ethanol-water with methanol, ethanol-toluene with acetone, and methyl ethyl ketone-benzene with acetone; three maxT azeotropic mixtures with a light entrainer (1.0-1a class), namely, water-ethylenediamine with methanol, acetone-chloroform with dichlomethane, and propanoic acid-dimethyl formamide withmethyl isobutyl ketone; and one low-α mixture with a light entrainer (0.0-1 class), namely, ethyl acetate-benzene with acetone, were studied in a stripping extractive column. For the 1.0-2 class, both A and B can be recovered as the bottom product, depending on the location of αAB = 1, which sets limiting values for the entrainer feed flow rate FE/LT for one of the product. In addition, the feasible region of the extractive distillation process is larger than for the azeotropic distillation process. For the 1.0-1a class, the product is either A or B, depending on the location of αAB = 1, which sets a minimum value of (FE/LT)min for one of the product. For the 0.0-1 class, feasibility depends on the existence αAB = 1. When it does not exist, B is the unique possible product. When it does, both A and B are products, with B below a maximum value of (FE/LT)max,B and A above a minimum value (FE/LT)min,A

Mots clés: Batch extractive distillation; Stripping column; Light boiling entrainer; Univolatility lines

Domaines: Génie chimique; Génie des procédés

Ivonne Rodríguez-Donis, Vincent Gerbaud, Xavier Joulia. Thermodynamic Insights on the Feasibility of Homogeneous Batch Extractive Distillation. 3. Azeotropic Mixtures with Light Boiling Entrainer. Industrial and engineering chemistry research, 2012, 51 (2), pp.4643-4660. ⟨10.1021/ie201942b⟩. ⟨hal-02354756⟩