| Summary: | 碩士 === 東海大學 === 化學工程學系 === 91 === The idea of reactive distillation is not new; however, it has received renewed attention in recent years. According to Malone and Doherty (2000), a lot of articles concerning the reactive distillation have been published during last two decades. However, most of these publications are concerned about process design, chemical reaction, and equilibrium, etc. Only very few of these provide guidelines to practical decision on operating strategies, control system design, instrumentation, etc. The study explores the plantwide control of an ethyl acetate reactive distillation process. First, a steady-state design for an ethyl acetate reactive distillation process consisting of a reactive column and two recovery columns using Aspen Plus software was investigated. Then, a rigorous dynamic simulator for the whole plant based on Franks’(1972) physical model was developed. Dynamic simulation and controllability studies for the reactive distillation process with five control structures were also investigated. To avoid the ”snowball effect”, the flow rates of the two recycle streams were fixed and makeup fresh feeds of ethanol and acetic acid were brought on level control for each control structure. Two of the five control structures are workable, but others are not so suitable when the water concentration in the acetic acid feed is increasing. It was found in this study that if the configuration of a steady-state process design is not properly arranged, it might cause plantwide control difficulties. The developed dynamic simulator based on Franks’ (1972) model is an effective tool for the analysis and design of such plantwide control system. Moreover, it was also found in this study that effectively maintaining the molar ratio of acetic acid to ethanol in the feed of the reactive column is the key control point for this ethyl acetate plant. Simulation results also demonstrated that the proposed control structures without using any on-line analyzer could maintain the product purity very well even in the presence of a dramatic concentration change in the acetic acid feed or in the ethanol feed.
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