Conceptual design and plantwide control of an ethyl acetate process

Abstract The conceptual design and control of a “reaction followed by separation” process for producing ethyl acetate via esterification of ethanol with acetic acid is evaluated. A zero waste discharge process flowsheet is synthesized using the residue curve map tool. It consists of a boiling reactor-rectifier, followed by an ester purification section with a liquid–liquid extractor and two distillation columns. Steady state analysis reveals the presence of two types of composition profiles for the reactor-rectifier that achieve the desired production rate and quality. The process is designed for the profile that gives lower total energy consumption. The dominant design variables for the process flowsheet, namely, reactor-rectifier pressure and reactant excess ratio are adjusted to obtain an economic design. The developed process design is ∼20% more energy efficient compared to extant literature reports. Further, a novel plantwide control structure with the feed to the extractor as the throughput manipulator (TPM) is shown to require no equipment overdesign when using established equipment sizing heuristics. In contrast, conventional control with TPM at a fresh feed requires overdesign ranging from 10 to 20% in recycle loop equipment size. The work illustrates the significant impact of plantwide control structure on the necessary equipment overdesign.

[1]  Stanley M. Walas,et al.  Chemical Process Equipment : Selection and Design , 1988 .

[2]  Nitin Kaistha,et al.  Continuous Monoisopropyl Amine Manufacturing: Sustainable Process Design and Plantwide Control , 2015 .

[3]  W. Luyben,et al.  Tuning PI controllers for integrator/dead time processes , 1992 .

[4]  Nitin Kaistha,et al.  Continuous diisobutylene manufacturing: Conceptual process design and plantwide control , 2017, Comput. Chem. Eng..

[5]  Richard Turton,et al.  Analysis, Synthesis and Design of Chemical Processes , 2002 .

[6]  Sebastian Engell,et al.  Conceptual design and optimization of chemical processes under uncertainty by two-stage programming , 2015, Comput. Chem. Eng..

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

[8]  Hsiao-Ping Huang,et al.  Design and control of an ethyl acetate process: coupled reactor/column configuration , 2005 .

[9]  John Griswold,et al.  Phase Equilibria in Ethyl Alcohol–Ethyl Acetate–Water System , 1949 .

[10]  N. Kaistha,et al.  Steady State Analysis of Reactive Distillation Using Homotopy Continuation , 2005 .

[11]  Nilay Shah,et al.  An optimisation-based framework for the conceptual design of reaction-separation processes , 2016 .

[12]  Rafiqul Gani,et al.  State‐of‐the‐art and progress in the optimization‐based simultaneous design and control for chemical processes , 2012 .

[13]  W. Luyben.  Design and Control of the Styrene Process , 2011 .

[14]  Hsiao-Ping Huang,et al.  Control of reactive distillation process for production of ethyl acetate , 2007 .

[15]  W. Luyben.  Design and control of the ethyl benzene process , 2011 .

[16]  Kelvin T. Erickson,et al.  Plantwide process control , 1999 .

[17]  Bingjiang Zhang,et al.  Design and simulation of an entrainer-enhanced ethyl acetate reactive distillation process , 2011 .

[18]  N. Kaistha,et al.  Steady-State Multiplicity and Its Implications on the Control of an Ideal Reactive Distillation Column , 2008 .

[19]  S. Ellis,et al.  A New Equilibrium Still for the Study of Partially Miscible Systems , 1960 .

[20]  Sigurd Skogestad,et al.  An industrial and academic perspective on plantwide control , 2009 .

[21]  W. Luyben.  Snowball effects in reactor/separator processes with recycle , 1994 .

[22]  Cheng-Ching Yu,et al.  Plantwide Design of Transesterification Reactive Distillation to Co-Generate Ethyl Acetate and n-Butanol , 2010 .

[23]  James J. Downs,et al.  Influence of Process Variability Propagation in Plantwide Control , 2012 .