Yeong-Tarng Tang, Yi-Wei Chen, Hsiao-Ping Huang, and Cheng-Ching Yu Dept. of Chemical Engineering, National Taiwan University, Taipei 106-17, Taiwan Shih-Bo Hung and Ming-Jer Lee
Dept. of Chemical Engineering, National Taiwan University of Sci. Tech., Taipei 106-07, Taiwan DOI 10.1002/aic.10519 Published online April 21, 2005 inWiley InterScience (www.interscience.wiley.com).
The reactive distillation provides an attractive alternative for reaction/separation processes with reversible reactions, especially for etheriﬁcation and esteriﬁcation. The discrete nature of chemical species and the complexity of phase equilibria seem to cloud the picture in understanding reactive distillation. The esteriﬁcations of acetic acidwith ﬁve different alcohols, ranging from C1 to C5, are studied. First, qualitative relationships between macroscopic process ﬂowsheet and microscopic phase equilibria are established, and the process ﬂowsheets are classiﬁed into type I, II, and III for these ﬁve systems. Next, a systematic design procedure is devised to optimize the design, based on the total annual cost (TAC) and dominant designvariables are identiﬁed for different ﬂowsheets. Once quantitative design is available, process characteristic are analyzed and potential problems in process operation are identiﬁed. Finally, the economic potentials of these three different ﬂowsheets are explored and explanations are given. The results clearly indicate that it is possible to systemize the design of reactive distillation byqualitatively generating ﬂowsheet from phase equilibria and by quantitatively completing the process ﬂow diagram from a sequential design procedure. Moreover, some of the ﬂowsheets presented in this work cannot be found elsewhere in the open literature. © 2005 American Institute of
Chemical Engineers AIChE J, 51: 1683–1699, 2005
Keywords: esteriﬁcation, acetate, reactive distillation, process designIntroduction
Reactive distillation provides an attractive alternative for process intensiﬁcation, especially for reaction/separation systems with reversible reactions. The literature in reactive distillation has grown rapidly in recent years and the books by Doherty and Malone1 and Sundmacher and Kienle2 give updated summaries in the ﬁeld. Taylor and Krishna3 give an in-depth review onpotential advantages and hardware conﬁgCorrespondence concerning this article should be addressed to C.- C. Yu at email@example.com.
© 2005 American Institute of Chemical Engineers
urations. As pointed out by Doherty and Buzad,4 the concept of combining reaction and separation has long been recognized, but rarely put into commercial practice, not until the successful application for the productionmethyl acetate.5 Despite clear advantages of simultaneous reaction/separation,6 commercializing of reactive distillation processes is still quite limited for several reasons. An obvious one is mentioned in4 “There is almost always a conventional alternative to reactive distillation which is seductive because we have always done it this way”. The scenario remains more than a decade later. After themanagement and technical levels were convinced by the clear edge of reactive distillation, another reason is that the process ﬂowsheets seem to change from case to case (for example,
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from methyl acetate, to ethyl acetate, to butyl acetate and so on).5,7,8,9,10,11 Even for the same chemical production (for example, ethyl acetate, butyl acetate,and so on), the ﬂowsheet conﬁgurations also vary8,9,10,11 as one went through the literature. Unlike the conventional distillation, the seemingly casebased design approach and a great deal of process conﬁgurations (to choose from) add additional complexity to reactive distillation. A number of chemical systems have been studied in the literature using reactive distillation columns and among the...