Condensation of binary mixtures of vapours of immiscible liquids

The condensation of mixtures of vapours of immiscible liquids is a process which occurs frequently in the oil and chemical process industries, particularly where such processes as steam distillation, heterogeneous azeotropic distillation and solvent drying are used. Yet the process is not understood. The discrepancies between the heat transfer coefficients reported by previous workers in this field are so large that none of the published correlations can be confidently used for design purposes. The relationships found between heat transfer coefficient and temperature driving force differ so widely that it is impossible to predict., without prior experimentation, the behaviour of condensers when operating conditions are changed. The present state of knowledge in this field is such that it is not known whether the factor controlling heat transfer rate during condensation is simply the conductive resistance of the condensate layer, or whether the conditions at the vapour–liquid interface are of importance. A need for further work in this field is obvious. The work described in this thesis covers the design and development of an apparatus to investigate the process of condensation of mixtures of vapours of immiscible liquids and an experimental study in which local heat transfer coefficients have been measured and related to visual observations of the condensate flow pattern.