Journal review. Azeotropic distillation

Abstract

Recent and ongoing research in the distillation of nonideal mixtures is reviewed focusing on advances in the methodologies for the synthesis, design, analysis and control of separation sequences involvinghomogeneous and heterogeneous azeotropic towers. Maps of residue curves and distillation lines are examined, as well as geometric methods for the bynthesis and design of separation sequences, trends in the steady-state and dynamic analysis of homogeneous and heterogeneous towers, the nonlinear behavior of these towers, and strategies for their control.Emphasis is placed on the methods of computing all of the azeotropes associated with a multicomponent mixture, on the features that distinguish azeotropic distillations from their zeotropic counterparts, on the potential ,for steady-state multiplicity, and on the existence of maximum and minimum reflux bounds. Important considerations in the selection of entrainers are examined. For the synthesis of separation trains, when determining the feasible product compositions, the graphical methods are clarified, especially the conditions under which distillation bounduries can be crossed and bounding strategies under finite reflux. The application of geometric theory to locate the fuced points, at minimum reflux, is reviewed in connection with homotopy-continuation algorithms for this purpose. The use of homotopy-continuation algorithms, especially for the steadystate simulation of heterogeneous azeotropic distillations, is justified. Methods for phase stability analysis are reviewed in connection with the location of real bifurcation points at phase transitions, an important feature of algorithms for the dynamic simulation of heterogeneous azeotropic distillations. Azeotropy and polyazetropyfueotrope, an ancient Greek word that translates as "to 96 January 1996 Vol. 42, No.

A novel method for detecting and computing univolatility curves in ternary mixtures

“…Particularly, the review paper of Kiva et al (2003) provides a comprehensive historical review of RCMs mainly taking into account the Serafimov's classification of 26 RCM diagrams of ternary systems (Hilmen et al,2002). The important role of RCMs, unidistribution and univolatility manifolds has been well described by Widagdo and Seider (1996), Ji and Liu (2007), Skiborowski et al (2014) for azeotropic distillation process design and by Rodriguez-Donis et al (2009a, 2009b, 2012a, 2012b, Luyben and Chien (2010) and Petlyuk et al (2015) for extractive distillation design purposes. Noteworthy, the existence and the position of the univolatility curve, a particular type of isovolatility curve, determine the component to be drawn as distillate as well as the configuration of the extractive distillation column.…”

Design and optimization of recycle policies for multicomponent azeotropic distillation processes with bifurcation analysis

“…Usually there are several competing design alternatives. A typical example is the purification of an ethanol-water mixture where process alternatives based on heterogeneous distillation (Pham et al, 1989, Urdaneta et al, 2002, extractive distillation (Brüggemann and Marquardt, 2003), pressure-swing distillation (Knapp and Doherty, 1992), exploitation of a highly curved boundary (Widagdo and Seider, 1996) and combination of distillation and pervaporation (Bausa and Marquardt, 2000) are known. Due to the recycle streams, the mass balances of each of these processes are characterized by one or more degrees of freedom.…”

Modelling of a dynamic multiphase flash: the positive flash

“…Such issues are particularly significant for the study of distillation column start up and shut down and of heterogeneous azeotropic distillation column where "… the interface between trays having one and two liquid phase(s) moves in response to disturbances (Widagdo and Seider, 1996)". To detect, handle and manage phase pattern changes in phase equilibrium related dynamic processes, reliable dynamic models are required.…”

“…To detect, handle and manage phase pattern changes in phase equilibrium related dynamic processes, reliable dynamic models are required. As summarized in a review on azeotropic distillation by Widagdo and Seider (1996), "it is important to accurately compute the phase distributions when performing dynamic simulation for heterogeneous azeotropic distillations.". Today, two kinds of approaches are usually proposed, namely the equation solving approach and the global stability analysis (Müller and Marquardt, 1997) which combined search of the number of coexisting phases and solving of the relevant set of equations.…”