Energy conservation by multi-effect batch distillation system

A multi-effect batch distillation system, MEBAD, which separates multiple components simultaneously, has higher energy efficiency compared with an ordinary batch distillation column. In this paper, in order to make the characteristics of the MEBAD clearer, the energy consumption of the MEBAD is compared with that of a conventional continuous distillation system for various feed conditions. Results of the exhaustive simulations show that the MEBAD has the potential for having a higher energy efficiency than a continuous system when the number of components is increased of relative volatilities among the components are decreased. Furthermore, it is shown that there is little relationship between the number of column stages and the energy consumption at the reboiler of the MEBAD while the number of stages strongly affects the energy consumption of the continuous system. The reason why the number of stages does not affect the energy consumption of the MEBAD is explained from the relationship between the operating line and the VLE curve.