Optimization-Based Approach To Process Synthesis for Process Intensification: General Approach and Application to Ethanol Dehydration

Abstract

Process synthesis and intensification are well-known and powerful tools for the development of chemical processes with improved energy and cost efficiency. However, even though a combination of both provides the most potential for exploiting these improvements, process synthesis still focuses on classical unit operations, while intensified process options are rather delayed and considered mainly for retrofitting. This not only limits the result of process synthesis but also impedes the application of intensified process options, as they need to justify additional investment for process modification. In order to reveal improved process options and reduce the barrier for intensified processes, the current article presents a process synthesis approach which generates thermodynamically feasible phenomena-based flowsheets by means of superstructure optimization. The approach provides maximum flexibility for integrating and modifying the involved phenomena building blocks, which only afterward are interpreted and translated into equipment that represents the final process. Innovative hybrid process configurations and intensified equipment can thereby be synthesized automatically in conceptual design. The current article introduces the general concept and the implementation for an initial set of phenomena building blocks. Successful application of the approach is demonstrated for the nonreactive but thermodynamically nonideal case study of ethanol dehydration.

Analysis of TBA‐Based ETBE Production by Means of an Optimization‐Based Process‐Synthesis Approach

“…The following subsections provide a brief description of the framework, as well as the PBB. Further details on the framework as well as specific PBB models and the implemented optimization approach are provided in preceding articles, which introduced the method for the case studies of ethanol dehydration and the transesterification of propylene carbonate .…”

“…Process synthesis framework divided into five subsequent steps. Reprinted with permission from Kuhlmann and Skiborowski . Copyright (2018) American Chemical Society.…”

“…Bottom: PBB schematic with corresponding mixers and splitters. Reprinted with permission from Kuhlmann and Skiborowski . Copyright (2018) American Chemical Society.…”

“…Neither temperature and concentration polarization nor pressure drop are considered for the PBB models, for an ideal and equipment‐independent performance evaluation. The mathematical models for the VL‐PBB and the VP‐PBB as well as the RN‐PBB have been introduced in the preceding articles on the optimization‐based approach to process synthesis for process intensification , . As indicated by the gray box in Fig.…”

“…This is of specific importance for the considered synthesis problem, which on the one hand involves a large number of complex nonlinear and non‐convex equations based on the thermodynamic models, while on the other hand no specific structure is to be assumed that would facilitate the use of tailored initialization modes as proposed by Skiborowski et al , . A detailed description of the optimization approach, the prescreening procedure and the initialization routine is provided in the article of Kuhlmann and Skiborowski .…”