Computers & Chemical Engineering, Vol.21, No.S, 1221-1226, 1997
Optimal Operation Policy for Multieffect Batch Distillation System
The optimal operation policy which minimizes the total batch time is derived for a new type of separation system called "Multi-Effect BAtch Distillation system (MEBAD)." The MEBAD consists of a set of batch distillation columns connected sequentially and separates (M+1) components by M columns simultaneously. The feature of this system is that only the first column has a reboiler and only the final column has a condenser. The results of optimizations show that the feature of the optimal holdup policy depends mainly on the vapor liquid equilibrium relationship. In most cases, especially when the relative volatilities among the components are constant, the following strategy minimizes the total batch time : First, almost all of the raw material is fed to the reboiler, and the holdups of remaining vessels are gradually increased up to the final holdup. The optimization results of ten example problems show that by optimizing the vessel holdups with respect to time, a 47 % reduction on average of the total batch time is achieved.
Keywords:MIDDLE VESSEL;COLUMN