Prediction of the Operating Conditions in a Batch Distillation Column Using a Shortcut Method

A shortcut procedure as quick, easy-to use method for design and simulation of multicomponent batch distillation is used to predict the operating condition of recovering xylene from solvent in an existing batch distillation column in benzol refinery. The procedure can be used to investigate the effect of the operating parameters on the operation of column for three possible modes of batch distillation operations; constant reflux, variable reflux and step wise change in the reflux ratio. It is shown that step wise change in the reflux ratio, in comparison with a fixed ratio mode, can significantly reduce the required operation time and makes the operation more economical even at high reflux ratios. Applying the procedure in a batch distillation column (National Iranian Steel Cooperation) with 35 bubble-cap trays, mixed-xylenes were produced in a desired purity of 95% with a recovery of 92.5% from a feedstock containing 40% xylenes.