Design and Optimization of Thermally Coupled Extractive Distillation Sequences

In this paper, design and optimization procedures are developed for a conventional extractive distillation sequence and a thermally coupled extractive distillation scheme. The proposed methodologies detect the optimal values of the design variables in order to guarantee the minimum energy consumption. It was found that the optimum energy consumption can be related to the minimum total annual operating cost, minimum greenhouse gas emissions, higher thermodynamic efficiencies and good theoretical control properties. The methodologies were applied to the study of the separation of several close boiling point mixtures using the two distillation sequences. The results showed that the energy savings predicted in the complex extractive distillation sequence can be achieved along with reductions in greenhouse gas emissions.