Shortcut methods for nonideal multicomponent distillation: 3. Extractive distillation columns

Abstract

Extractive distillation is a common process for the separation of homogeneous azeo

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

“…Process feasibility has been evaluated for continuous (Widagdo and Seader, 1996) and batch (Rodriguez-Donis et al, 2001a,b, Skouras et al 2005 azeotropic distillation for all significant Serafimov's classes and led to major industrial applications in the continuous operation mode. For homogeneous extractive distillation, class 1.0-1a has been thoroughly investigated for a continuous column (Knapp and Doherty, 1994;Hilmen, 2000;Brüggemann and Marquardt, 2004) and only 0.0-1; 1.0-1a; 1.0-1b and 1.0-2 classes for a batch rectifier or stripper column (Steger et al, 2005, Varga, 2006. For heterogeneous batch extractive distillation, only 2.0-2b class has been studied in detail (Rodriguez-Donis et al, 2003a;Varga et al, 2005).…”

“…The effect of reflux is complex because it induces major topological changes on the extractive profile map with the occurrence of extractive boundaries crossing at extractive saddle points and reducing the feasibility composition region (Knapp and Doherty, 1994;Lelkes et al, 1998a;Brüggemann and Marquardt, 2004). Hence,…”

Thermodynamic Topological Analysis of Extractive Distillation of Maximum Boiling Azeotropes

“…Based on the calculation of the still path and possible composition profiles of the column sections, Lang et al (2000a, b) extended the feasibility of extractive distillation in a batch rectifier for the investigation of the separation of maximum azeotropes, Rodriguez-Donis et al (2009a, 2012a studied the maximum azeotropic mixture separation. However, extractive distillation studies have always considered a heavy entrainer to split a minimum boiling azeotrope which belongs to class 1.0-1a (Knapp and Doherty, 1994a;Luyben, 2008aLuyben, , 2008bBrüggemann and Marquardt, 2004). Düssel and Stichlmair (1995) proposed a hybrid method by replacing one distillation step into a decantation or absorption, which is less energy intensive for the separation of minimum azeotropes with a heavy entrainer.…”

Conceptual Design of Azeotropic Distillation Processes

“…Therefore, feasibility of extractive distillation is limited by some minimum entrainer flow rate and a minimum and a maximum reflux ratio [56]. These limits can also be computed applying concepts from bifurcation theory [59,61] to extend the assessment of feasibility to mixtures with more than three components.…”

“…Figure 8.1). Shortcut methods are of special interest for extractive distillation, since they allow for a fast evaluation of process performance for different entrainer candidates [61]. While split feasibility and MED of the entrainer recovery column can be assessed by the methods discussed so far, two-feed columns require an adjustment of the shortcut methods to account for the distinct feed positions.…”