Synthesis of distillation configurations: I. Characteristics of a good search space

Abstract The exhaustive enumeration of all possible distillation configurations for zeotropic n -component feed mixtures into n nearly pure product streams leads to an exponentially large number of configurations, making the search for an optimal configuration intractable for even a modest number of components. To reduce the search space to a manageable level, we divide the column configurations into two categories: (i) Basic , configurations having ( n  − 1) distillation columns; and (ii) Non-basic , configurations having more columns. On exhaustively simulating multiple four-component feed conditions using Underwood's method for pinched columns, we find that for none of the simulated feed conditions does a non-basic configuration have a lower heat duty than the lowest heat duty basic configuration. Based on this observation, we assert that a much smaller search space containing only basic configurations should be sufficient to find an optimal n -component configuration. We also find basic configurations allowing non-sharp splits (ABC → AB/BC) have lower heat duty more often than those with only sharp splits (ABC → A/BC or ABC → AB/C). Finally, the heat duty reduction due to thermal coupling is found to be less when compared to non-sharp basic configurations as against sharp-split basic configurations.

[1]  Ignacio E. Grossmann,et al.  Generalized Disjunctive Programming Model for the Optimal Synthesis of Thermally Linked Distillation Columns , 2001 .

[2]  Sigurd Skogestad,et al.  Operation of Integrated Three-Product (Petlyuk) Distillation Columns , 1995 .

[3]  Ignacio E. Grossmann,et al.  Design of distillation sequences: from conventional to fully thermally coupled distillation systems , 2004, Comput. Chem. Eng..

[4]  Rakesh Agrawal,et al.  Synthesis of Distillation Column Configurations for a Multicomponent Separation , 1996 .

[5]  Michael F. Malone,et al.  Conceptual design of distillation systems , 2001 .

[6]  Jude T. Sommerfeld,et al.  Catalan numbers in process synthesis , 1986 .

[7]  Roger W. Thompson,et al.  Systematic synthesis of separation schemes , 1972 .

[8]  Zbigniew T. Fidkowski,et al.  Thermally coupled system of distillation columns: Optimization procedure , 1986 .

[9]  Zbigniew T. Fidkowski,et al.  Distillation configurations and their energy requirements , 2006 .

[10]  R. Agrawal,et al.  Are Thermally Coupled Distillation Columns Always Thermodynamically More Efficient for Ternary Distillations , 1998 .

[11]  Rakesh Agrawal,et al.  More Operable Fully Thermally Coupled Distillation Column Configurations for Multicomponent Distillation , 1999 .

[12]  Arthur W. Westerberg.  The synthesis of distillation-based separation systems , 1985 .

[13]  Rakesh Agrawal,et al.  Synthesis of multicomponent distillation column configurations , 2003 .

[14]  Arthur Westerberg,et al.  A retrospective on design and process synthesis , 2004, Comput. Chem. Eng..

[15]  Z. Fidkowski,et al.  Minimum energy requirements of thermally coupled distillation systems , 1987 .

[16]  F. Petlyuk.  Thermodynamically Optimal Method for Separating Multicomponent Mixtures , 1965 .

[17]  Ilkka Turunen,et al.  Synthesis of Functionally Distinct Thermally Coupled Configurations for Quaternary Distillations , 2003 .

[18]  Arthur W. Westerberg,et al.  Shortcut methods for complex distillation columns. 1. Minimum reflux , 1981 .

[19]  M. Powell.  Optimization in action: 7th–9th January 1975. University of Bristol, UK. Organized by the Institute of Mathematics and its Applications, Essex, UK , 1975 .

[20]  C. Floudas,et al.  A mixed-integer nonlinear programming formulation for the synthesis of heat-integrated distillation sequences , 1988 .

[21]  Nikolaos V. Sahinidis,et al.  Global optimization of mixed-integer nonlinear programs: A theoretical and computational study , 2004, Math. Program..

[22]  Rakesh Agrawal,et al.  Multicomponent thermally coupled systems of distillation columns at minimum reflux , 2001 .