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Evaporation rate and separation factor of molecular distillation in a falling film apparatus
Author(s) -
Kawala Zdzislaw,
Stephan Karl
Publication year - 1989
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.270120158
Subject(s) - evaporation , distillation , mass transfer , chemistry , falling (accident) , volumetric flow rate , fractional distillation , vacuum distillation , continuous distillation , separation (statistics) , chromatography , thermodynamics , heat transfer , binary number , mechanics , separation process , analytical chemistry (journal) , materials science , medicine , physics , arithmetic , environmental health , mathematics , machine learning , computer science
During molecular distillation in a falling film apparatus, temperature and concentration of the more volatile components undergo a marked decrease in axial and radial directions, due to the distillation in vacuo. The gradients produce changes in the rate of surface evaporation and separation efficiency along the flow path. A theoretical study of this problem is presented for binary mixtures. The respective differential equations for heat and mass transfer in the liquid film are solved numerically. As the results demonstrate, the aspect ratio of an apparatus should be large when a high separation is required and small when a high distillation rate is more important.