comprehensive evaluation of side-absorber distillation column performance in ethanol extractive dehydration

A side-absorber distillation column (sadc) model was used for ethanol extractive dehydration (eed) with ethylene glycol (eg) as the solvent for the first time. the model performance was evaluated in terms of product purity, energy consumption rate, and the amount of solvent used. initially, the system behavior was analyzed from a thermodynamic point of view. then, the process was simulated, and the effect of all operational and design variables was separately and simultaneously evaluated through sensitivity analysis. by determining the optimal value of each variable, the sadc model was optimized. using the optimized structure, ethanol with a molar purity of 99.8% and a specific energy consumption rate of 0.325 kwh/kg was extracted. then, the performance of the sadc structure was operationally compared with classical two-column (ctc) and dividing wall column (dwc) configurations. in addition to maintaining high purity, the sadc model can reduce the reboiler heat duty by 37% and 30%, respectively, compared to the ctc and dwc structures. the amount of solvent consumed in the sadc structure was also reduced by 26.3% compared to the other two configurations. on the other hand, the sadc model is simpler and structurally smaller than other models, and it imposes less investment and operational costs.