Design Methodology for Screening Dynamic Characteristics of Candidate Heat-Integrated Flowsheets

Abstract

Well-established design methods exist for generating candidate heat-exchanger networks (HENs), but there is a strong need for a methodology to screen for undesirable dynamic characteristics that are often observed in heat-integrated processes. In this paper, a simple transfer function-based method is developed that can assist in comparing dynamic behavior of candidate heat-integrated flowsheets. Use of the method allows the design engineer to determine the dynamic characteristics of the overall process shortly after identifying exchanger networks that satisfy the process heat balance. Mathematical development of the method is given, followed by explanations of its use. The basis of the method is developed in block-diagram format, making apparent the source of positive feedback that can result from adding heat integration to a process. Finally, the method is demonstrated on three candidate HENs for a simple process. The method allows for identification of dynamic characteristics that would not be determine...