(71b) Predicting the Liquid-Side Mass-Transfer Resistance of Structured Packings: State of the Art

Well established correlations for estimating the liquid-side mass transfer coefficient of structured packings have been thoroughly evaluated using experimental evidence on overall performance obtained in total reflux distillation tests with various systems as employed at FRI, SRP, TUD, Sulzer, Bayer TS, etc. Strikingly large differences are found between different methods with respect to both the absolute values of mass transfer coefficients and the trends with respect to increasing vapor and liquid loads. This and other issues particularly that about the magnitude of relative contribution of liquid-side to overall mass transfer resistance, which according to new data seems to be larger in distillation than generally believed, are discussed and aview on the way forward including research needs and suggestions for implementing physically sound improvements to existing predictive models given.