(245k) Minimization of Entropy Generation in Multi-Pressure Reactive Distillation Networks

Authors: 
da Cruz, F., University of California, Los Angeles
Manousiouthakis, V., University of California Los Angeles, Los Angeles
In the synthesis of reactive distillation networks, a promising process intensification technology, different pressure levels are allowed to be used to overcome the azeotropes, which can enhance the separation process. Nevertheless, the use of reactions or pressure swing to execute a separation can lead to different levels of entropy generation for the system. The amount of entropy generated in a process can be used as a measure the energetic efficiency of the system. Looking from the angle of availability analysis, the amount of entropy generated in a process is directly related to the destruction of available work.

A methodology for the globally optimal synthesis of a reactive distillation network with minimum entropy generation, under certain conditions, is presented in this work. The proposed methodology employs the Infinite DimEnsionAl State-Space (IDEAS) conceptual framework, which is shown to be applicable to the problem under consideration. The IDEAS framework considers an infinite number of units with all physically possible mixing and splitting streams existing between them. The resulting mathematical formulation is an infinite-dimensional program (ILP). Using the proposed formulation, the objective function of minimum entropy generation is function of only the outlet streamsâ?? composition, regardless of the number of units or interconnections the reactive distillation network contains. The method is demonstrated on a case study involving the multi pressure reactive distillation of methanol/isobutene/MTBE azeotropic mixture.

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