Avaliação termodinâmica do processo de destilação: nova proposta de cálculo de performance.

Abstract

The distillation process has received special attention from researchers due to high energy consumption and low thermodynamic efficiency. However, thermodynamic performance has been approached in the literature in a superficial way, so that exergetic efficiency and thermodynamic efficiency are often treated as synonyms, as well as the intrinsic variables of the calculation of these as exergy, availability and availability function, which are not are well defined in the literature. The main objective of this work is to develop a rigorous thermodynamic analysis of the distillation process, conventional and extractive, including a critical evaluation of the ways of calculating efficiency and parameters involved, in addition to proposing a new way of calculating thermodynamic performance for the distillation process. To make the thermodynamic analysis more detailed, the extractive distillation process will be considered from the global point of view and from each column involved in this process. The mixtures considered for conventional and extractive distillation will be, respectively, benzene (BZN) and toluene (TOL) and the azeotropic binary acetone (ACET) and methanol (METOH) using dimethylsulfoxide (DMSO) as solvent. The results for conventional thermodynamic evaluation show that even in conventional distillation, in which there is no solvent, the thermodynamic efficiency is low, and, depending on the operational condition, negative values are obtained. A new way of evaluating thermodynamic performance is proposed: thermodynamic inefficiency, with which results with well-defined physical meaning that vary positively can be obtained.