The overall plate efficiency of vapor-liquid-liquid three-phase distillation was investigated in a sieve-tray Oldershaw distillation column of 50mm diameter . In froth flowregime

the effects on mass transfer of the operating conditions

e.g. vapor velocity and liquid to vapor loading ratio

and the physical properties of liquid phase

including surface tension

interfacial tension

dispersion viscosity

density

diffusion coefficient

relative volatility etc.

were systematically studied . The influence of the oil to water volume ratio on overall efficiency was also investigaed . Three-phase and two-phase distillation operations were compared in terms of plate efficiency . An analysis of the experimental results showed that the overall efficiency for three-phase distillation was lower than that for two-p hase distillation and interfacial tension and dispersion viscosity are the main influence factors . Finally

a correlation equation of overall efficiency for vapor-liquid-liquid three-pha se distillation in froth regime was obtained by regression of experimental data . This empirical correlation may be of some value in design and optimization .