Equation‐oriented optimization of process flowsheets with dividing‐wall columns

We present a new modeling approach for dividing-wall columns (DWCs) that is amenable to equation-oriented flowsheet simulation and optimization. The material, equilibrium, summation, and heat (MESH) equations describing a DWC are highly coupled and nonlinear, making DWC-based process flowsheets challenging to simulate. Design optimization poses further challenges, typically requiring integer variables to select the number of column stages. To address these difficulties, we represent DWCs as networks of pseudo-transient (differential-algebraic) subunit models. We show that these networks have the same steady-state solution as the original (algebraic) MESH equations, but present significant numerical benefits. We then embed these models in a previously developed pseudo-transient flowsheet modeling and optimization framework. We further reformulate the models to require only continuous decision variables when selecting the optimal number of stages during design optimization. To illustrate these concepts, we discuss the DWC-based intensification of the dimethyl ether process. © 2015 American Institute of Chemical Engineers AIChE J, 2015

[1]  Michael Baldea,et al.  Equation-Oriented Models of Multistream Heat Exchangers for Flowsheet Optimization , 2014 .

[2]  Juan Gabriel Segovia-Hernández,et al.  Dividing Wall Distillation Columns: Optimization and Control Properties , 2008 .

[3]  Ignacio E. Grossmann,et al.  Aggregate models based on improved group methods for simulation and optimization of distillation systems , 2010, Comput. Chem. Eng..

[4]  Michael Baldea,et al.  Equation‐oriented flowsheet simulation and optimization using pseudo‐transient models , 2014 .

[5]  I. Grossmann,et al.  Optimal Design of Complex Distillation Columns Using Rigorous Tray-by-Tray Disjunctive Programming Models , 2000 .

[6]  C. Kelley,et al.  Convergence Analysis of Pseudo-Transient Continuation , 1998 .

[7]  Diane Hildebrandt,et al.  Column profile maps as a tool for synthesizing complex column configurations , 2010, Comput. Chem. Eng..

[8]  C. Triantafyllou,et al.  The design and optimisation of fully thermally coupled distillation columns : Process design , 1992 .

[9]  Jan Harmsen,et al.  Process intensification in the petrochemicals industry: Drivers and hurdles for commercial implementation , 2010 .

[10]  Ilkka Turunen,et al.  Energy saving and capital cost evaluation in distillation column sequences with a divided wall column , 2009 .

[11]  Ignacio E. Grossmann,et al.  Synthesis of complex thermally coupled distillation systems including divided wall columns , 2013 .

[12]  I. Grossmann,et al.  A combined penalty function and outer-approximation method for MINLP optimization : applications to distillation column design , 1989 .

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

[14]  Diane Hildebrandt,et al.  Complex Column Design by Application of Column Profile Map Techniques: Sharp-Split Petlyuk Column Design , 2010 .

[15]  K. A. Amminudin,et al.  Design and Optimization of Fully Thermally Coupled Distillation Columns: Part 1: Preliminary Design and Optimization Methodology , 2001 .

[16]  Ignacio E. Grossmann,et al.  Optimal synthesis of thermally coupled distillation sequences using a novel MILP approach , 2014, Comput. Chem. Eng..

[17]  Moonyong Lee,et al.  Dividing wall column structure design using response surface methodology , 2012, Comput. Chem. Eng..

[18]  Alexander W. Dowling,et al.  A framework for efficient large scale equation-oriented flowsheet optimization , 2015, Comput. Chem. Eng..

[19]  Michael F. Malone,et al.  New complex column arrangements for ideal distillation , 1986 .

[20]  Michael Baldea,et al.  Pseudodistributed Feed Configurations for Catalytic Plate Microchannel Reactors , 2014 .

[21]  Michael F. Malone.  Optimality Regions for Complex Column Alternatives in Distillation Systems , 1988 .

[22]  Anton A. Kiss,et al.  Innovative dimethyl ether synthesis in a reactive dividing-wall column , 2012, Comput. Chem. Eng..

[23]  Anton A. Kiss,et al.  Intensified process for aromatics separation powered by Kaibel and dividing-wall columns , 2013 .

[24]  Janez Levec,et al.  Correction to “Catalytic Dehydration of Methanol to Dimethyl Ether. Kinetic Investigation and Reactor Simulation” , 1993, Industrial & Engineering Chemistry Research.

[25]  Efstratios N. Pistikopoulos,et al.  Optimal design of dynamic systems under uncertainty , 1996 .

[26]  Jesús Rafael Alcántara-Ávila,et al.  Controllability analysis of alternate schemes to complex column arrangements with thermal coupling for the separation of ternary mixtures , 2008, Comput. Chem. Eng..

[27]  C. Pantelides,et al.  Optimal design of thermally coupled distillation columns , 1999 .

[28]  I. Grossmann,et al.  Disjunctive Programming Models for the Optimal Design of Distillation Columns and Separation Sequences , 2000 .

[29]  Alexander W. Dowling,et al.  Rigorous Optimization-based Synthesis of Distillation Cascades without Integer Variables , 2014 .

[30]  Noori Sotudeh,et al.  Extension of a Method for the Design of Divided Wall Columns , 2008 .

[31]  Ignacio E. Grossmann,et al.  An alternate MINLP model for finding the number of trays required for a specified separation objective , 1993 .

[32]  Anton A. Kiss,et al.  Innovative single step bioethanol dehydration in an extractive dividing-wall column , 2012 .

[33]  Michael Baldea,et al.  Identification-based optimization of dynamical systems under uncertainty , 2014, Comput. Chem. Eng..

[34]  Michael F. Malone,et al.  Minimum reflux, product distribution, and lumping rules for multicomponent distillation , 1984 .

[35]  Ignacio E. Grossmann,et al.  Optimal feed locations and number of trays for distillation columns with multiple feeds , 1993 .

[36]  A. A. Kiss,et al.  Enhanced bioethanol dehydration by extractive and azeotropic distillation in dividing-wall columns , 2012 .

[37]  Michael Baldea,et al.  Optimizing the catalyst distribution for countercurrent methane steam reforming in plate reactors , 2011 .

[38]  Juan Gabriel Segovia-Hernández,et al.  Optimal designs of multiple dividing wall columns , 2011 .

[39]  Costin Sorin Bildea,et al.  A control perspective on process intensification in dividing-wall columns , 2011 .

[40]  Michael Baldea,et al.  Multistream heat exchangers: Equation‐oriented modeling and flowsheet optimization , 2015 .

[41]  Claudia Gutiérrez-Antonio,et al.  Design and optimization, using genetic algorithms, of intensified distillation systems for a class of quaternary mixtures , 2009, Comput. Chem. Eng..

[42]  Anton A. Kiss,et al.  Revamping Dimethyl Ether Separation to a Single‐Step Process , 2013 .

[43]  J. Levec,et al.  Intrinsic and global reaction rate of methanol dehydration over .gamma.-alumina pellets , 1992 .

[44]  Michael F. Malone,et al.  Minimum Vapor Flows in a Distillation Column with a Sidestream Stripper , 1985 .

[45]  Anton A. Kiss,et al.  Comparison of Control Strategies for Dividing-Wall Columns , 2010 .

[46]  Juha Tanskanen,et al.  Homotopy parameter bounding in increasing the robustness of homotopy continuation methods in multiplicity studies , 2010, Comput. Chem. Eng..

[47]  Eugeny Y. Kenig,et al.  Dividing wall columns in chemical process industry: A review on current activities , 2011 .

[48]  W. Marquardt,et al.  Efficient Optimization-Based Design of Distillation Columns for Homogenous Azeotropic Mixtures , 2006 .

[49]  Mark J. Andrecovich,et al.  An MILP formulation for heat‐integrated distillation sequence synthesis , 1985 .

[50]  Ljubica Matijašević,et al.  Dividing wall column—A breakthrough towards sustainable distilling , 2010 .

[51]  Nina F. Thornhill,et al.  Integrated design and control using a dynamic inversely controlled process model , 2013, Comput. Chem. Eng..

[52]  Arturo Jiménez-Gutiérrez,et al.  Optimum design of Petlyuk and divided-wall distillation systems using a shortcut model , 2010 .

[53]  Moonyong Lee,et al.  Optimal retrofit design of extractive distillation to energy efficient thermally coupled distillation scheme , 2013 .