Análise energética rigorosa do processo de destilação por mudança de pressão: proposta de novo procedimento de otimização.

Abstract

There are several types of distillation found industrially; however, for the separation of binary azeotropic mixtures, two types stand out: distillation by pressure change and extractive distillation. The first is effective when the composition of the mixture varies significantly with pressure and the second when a suitable solvent can be used. Solvent selection strongly affects energy consumption and capital investment due to differences in selectivity, capacity and boiling point. The distillation process by pressure change ends up gaining space, as it is not necessary to add a third component for separation to occur, proving to be an excellent alternative for use on an industrial scale. However, to become competitive with the others, the partial or total thermal integration of the system needs to occurs. Several optimization methodologies are found in the literature. Commercial simulators such as Aspen PlusTM are widely used as tools for developing systematic procedures for optimizing the distillation process by pressure change. Within this context, this work aims to propose an optimization procedure applicable to the distillation process by pressure change. The acetone-methanol mixture was chosen as a case study and the process was simulated using Aspen PlusTM software. The results obtained show that it is essential to consider the non-ideality of the vapor phase, due to the strong influence on the liquid-vapour balance. For both configurations, the proposed optimization procedure obtained better results when compared to the works used as reference. In the configuration without thermal integration, the energy reduction of the total thermal loads of the reboilers (total Qr) was 13.7% and 5.8% lower; and for the configuration with thermal integration, the energy reduction of the total thermal loads of the reboilers (total Qr) was 30.26% and 4.84% lower, respectively.