Application of dividing wall column in azeotropic distillation with intermediate boiling-point heteroazeotrope: Simulation and optimization

Abstract

Dividing wall column (DWC), as a proven process intensification technology, has been used widely in separation of ideal multi-components, and some azeotrope systems. For heterogeneous azeotrope with the potential possibility of crossing distillation boundary by liquid-liquid splitting, it is advantageous to integrate liquid-liquid decanter with distillation column, especially with DWC to further simplify flowsheets and reduce energy consumption. In this work, existing heterogeneous azeotrope separation processes are described, and an innovative DWC-based process (MHADWC) is proposed for intermediate boiling-point heteroazeotropic systems. Then an industrial case of MIPK system, is used to evaluate mentioned configurations by rigorous simulation and optimization. These configurations are compared and analyzed in detail on energy consumption, exergy analysis and equipment invest. The results show that, from the perspective of process energy consumption, MHADWC process has the most advantages, because it saves 37% of energy consumption; if both equipment costs and exergy recovery are taken into account, HADWC2 has a higher thermodynamic efficiency (43.5%) at its TAC and can be used as a preferred target. And in this work, purification of an intermediate boiling-point heteroazeotrope is the main difference of these processes compared with the well-known heterogeneous azeotropic distillation process where the top vapor product is the lowest boiling point of the ternary system.