Distillation Times and Energy Consumption in Hyperfractionation of Real Binary Mixtures by the Total Reflux Process.

The distillation times and the energy consumption in hyperfractionation of a real methanol-water mixture in a discontinuously operating packed column with an infinite reflux ratio can be represented as functions of a dimensionless variable, the relative degree of fractionation. The use of this parameter has made it possible to identify a critical range - rather narrow and well defined - independent of the feed composition and of the operating conditions, which corresponds to the transition from the first distillation stage (in which appreciable differences exist between the composition of the overhead vapor and the distillate composition) to the following stage of true hyperfractionation. The possibility of using the relative degree of fractionation for the formulation of correlations for predicting-albeit in a first approximation - the times and energy consumption necessary to obtain a distillate in accordance with purity specifications, even when particularly restrictive.