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.

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This paper presents a systematic conceptual process design approach for the generation of flowsheet options with special focus on process intensification as it considers some integrated reaction−separation and hybrid separation techniques. For the identification of necessary separation steps and possible techniques, an automated tool was developed and implemented in Matlab. The objective of this tool is to find solutions to the design task with respect to predefined boundaries of the final process. In this context, thermodynamic insights that correlate physicochemical and thermodynamic properties of the chemical system with promising techniques are used. The approach is easy to extend by additional techniques, can be embedded into common process design frameworks, and is able to generate a meaningful variety of promising flowsheet options for a given design task. To underline its capabilities, the tool was applied to two design tasks, one of which is the separation of a nonideal fermentation supernatant, while the other represents the production of ethyl lactate. For both, promising flowsheet options were generated and discussed.

Process synthesis and intensification are powerful tools for the development of cost-and energy-efficient chemical processes. However, even though their combination maximizes the potential for improvements, they are mostly applied separately. The current article presents the extension of a phenomena-based process synthesis method by an aditional building block for reactor network synthesis and reactive separations. The method facilitates the automatic generation of thermodynamically feasible phenomena-based flowsheet variants by means of superstructure optimization, which are subsequently translated into equipment-based flowsheets taking into account classical as well as intensified equipment. By composing a flowsheet from mass and energy transfer phenomena instead of predefined unit operations, counterintuitive solutions and significant improvements can be achieved. In the current contribution, the capabilities of the method are demonstrated using the transesterification of propylene carbonate with methanol as a case study. The resulting optimal flowsheet represents a combination of integrated and hybrid separation steps for overcoming the intrinsic limitations of this system. The obtained result presents significant cost saving potential compared to those flowsheet variants previously generated by an alternative process synthesis method.