The effect of heat transfer between the phases on the performance of countercurrent distillation columns

Abstract

In distillation processes net evaporation or condensation in the bulk phases or at the interface is called thermal distillation. The causes of thermal distillation, especially mismatch between the rates of heat and mass transfer in and between the phases, are discussed. By taking thermal distillation into account in heat and material balances it is shown that the performance of countercurrent equipment should depend upon composition of the mixture and should have a maximum value, as has been found experimentally in this and in previous work. The experimental results indicate that the efficiency of the equipment is very low when the mixture is dilute, and this is not accounted for by the theory.