Rapid calculation of plate number and reflux ratio in batch distillation

Abstract

The method of B owman-Cichelli for determination of minimum reflux and plate requirements in binary batch distillations has been extended with a relation between these minimum requirements and the number of plates and reflux ratio to be used in practice. In the case that the concentrations in the column are in equilibrium with the bottom concentration at any moment during the distillation the effect of holdup, too, is accounted for. The application of the method of calculation has been simplified by the construction of three alignment charts with three additional diagrams. An experimental verification showed the method also to be applicable to systems with more than two components, if certain conditions are fulfilled. The concentrations in the column not in equilibrium with the bottom concentration give rise to an actual reflux ratio lower than that calculated; in some cases it may even be lower than the minimum reflux ratio.