Impact of the control properties on the energetic and economic performance of Heat-Integrated Distillation Columns under variable feed composition

Abstract

Heat Integrated Distillation Columns (HIDiC) are highly energy-efficient technologies whose performance has been validated through robust optimization algorithms and practical tests. Despite these configurations are dynamically controllable technologies, the simultaneous relationship between dynamics and optimal energetic and economic performance under variable feed composition has not been analyzed. Thus, this paper tackles this gap in literature. Five binary mixtures and three feed composition were examined in this study. The optimization of these configurations was firstly achieved using a Boltzmann-based optimizer while the control properties were obtained through the closed-loop process analysis using the IAE criterion and rigorous simulations in Aspen Dynamics in a second stage. Results showed that the HIDiC configurations with the best dynamic behavior do not match with the HIDiC columns with the best energetic and economic performance. However, suboptimal HIDiC configurations experienced only slightly less energetic and economic benefits but better dynamic properties that the best HIDiC configurations. Particularly, the best suboptimal HIDiC columns to separate the mixtures with relative volatility (α) lower than 1.4 were determined for a feed composition of 25 mol% for the light component. Nevertheless, the most adequate HIDiC columns to separate mixtures with α>1.4 were obtained for equimolar feed composition and feed composition of 75% for the light component.