Integration of Dividing Wall Columns with Middle Vessels for Batch Distillation under Total Reflux: Modeling and Optimization

Dividingwall columns, one of the thermally coupled distillationtechnologies, are widely used in the continuous separation processdue to their energy-saving advantages because multiple middle-vesselcolumns are an important improvement over traditional batch distillation(TBD). To save energy requirement and time consumption further forbatch distillation, a novel batch distillation configuration was proposed:the middle vessel-coupled dividing wall distillation column, whichis different from the other two configurations of TBD, and multiplemiddle-vessel batch distillation. Detailed modeling and optimizationof the above three configurations were conducted using a particleswarm algorithm, where the quaternary mixture of n-pentane (C5), n-hexane (C6), n-heptane (C7), and n-octane (C8) was used as a case.The results show that the separation time of the multiple middle-vesselcolumn was the shortest when the purity requirement was not high,while the separation capacity of the new configuration was the bestunder the same conditions and no intermediate cuts were produced.Finally, the operation strategy of the new configuration was improvedby adding fresh feed in the tank of the column top.