Influence of the Liquid or Vapor Split Ratios in Meta- or Parastillation Columns

The vapor phase, in parastillation, or the liquid phase, in metastillation columns, is divided at least into two internal flows. Two questions are addressed: (ii) Is splitting into two equal streams the best solution or can different split ratios have advantages? (ii) How sensitive is the process performance to fluctuations around the selected partition rate? Depending on the answers, these columns may require specific control systems. Nine split ratios, including the usual 50:50, were considered in binary and multicomponent alcoholic distillation. Separation is slightly sensitive to the split ratio, being more influenced by the Murphree efficiency. The effect of the split ratio decreases as the amount of ethanol in the feed increases. Fluctuations around the selected partition ratio do not affect, in a significant way, the process performance, and the corresponding control systems are not required. The obtained results indicate that it is better to improve tray efficiency than to control the phase split ratio.