Innovative side rectifier integration in distillation columns for improved ethanol extractive dehydration: performance and energy optimization

Abstract

This study presents a novel integration of a side rectifier in an extractive distillation process for ethanol dehydration, aiming to enhance both separation efficiency and energy performance. The new configuration, combining a distillation column with a side rectifier, is compared to the traditional two-column system, focusing on ethanol purity, energy consumption, and operational efficiency. The process uses two solvents: glycerol and Glycellin, a newly developed low-transition-temperature solvent. Simulation results, based on Aspen Plus with NRTL thermodynamic modeling, highlight the impact of key variables such as reflux ratio, solvent/feed ratio, and side-draw position on system performance. Sensitivity analysis revealed that the reflux ratio significantly influences energy efficiency, with optimal conditions yielding higher purity and reduced energy consumption in the new configuration. Notably, the system incorporating Glycellin showed superior performance, reducing energy consumption by 10–20% compared to the traditional two-column system. The energy consumption for the proposed configuration with Glycellin was 2931 kW, compared to 3450 kW for the conventional system. Additionally, the new design lowered the reboiler duty, offering a more sustainable and cost-effective solution for ethanol dehydration. The results underscore the potential of the side rectifier configuration, particularly with Glycellin, in advancing ethanol production processes by offering improved separation, reduced energy demands, and lower operational costs.