Modelling of fractionation in a molecular evaporator with divided condenser

Fractionation in a one-stage film evaporator can only be done by draining t he condensate from different heights of a divided condenser. We have shown the capabilities of this distillation in a short-path (molecular) evaporato r with a falling liquid film in a model study, taking into account heat and mass transfer in both liquid films on the evaporating and condensing surfa ces, and mass transfer in the vapour phase. The data on flows and compositi ons of fractions were obtained for a binary test mixture at various feed ra tes, feed compositions, evaporating and condensing temperatures, and at var ious condenser arrangements. This mode of short-path distillation in an eva porator with a divided condenser can be used for fractionation and in cases where recycling of some portion of distillate is required. The comparison of the experimental results with the model study results shows a satisfacto ry qualitative agreement between the experiment and the theory. (C) 2000 El sevier Science S.A. All rights reserved.