A new sulfolane aromatic extractive distillation process and optimization for better energy utilization

Abstract Extractive distillation (ED) processes are widely used for the separation of aromatic and non-aromatic hydrocarbons. Approximate boiling points of components and azeotropes in the mixture need solvents to aid the separation processes. A considerable mass flowrate and recovery of solvents in separation processes leads to significant energy requirement. This study provides a new extractive distillation process for the efficient separation of aromatic and non-aromatic hydrocarbons aided by sulfolane solution. A flash tank and a semi-lean solution stream are introduced to modify existing extractive distillation processes to reduce the reboiler heat duty of the entrainer recovery column and improve the separation performance of the extractive distillation column. The NRTL-RK property method and rigorous unit models in Aspen Plus are used to simulate new and existing processes. No-databank model parameters are regressed to improve the accuracy of simulations. A coordinative strategy is proposed to optimize the significant operating parameters for new and existing processes by combining Aspen Plus with MATLAB. Compared with the optimal existing extractive distillation process, the new extractive distillation process reduces the operating costs by 8.9% when heat integration is not considered, and 13.04% of the total annual cost can be reduced when a heat exchanger network is considered.