Isothermal vapor-liquid equilibrium of ethanol-water mixtures plus acetone-ethanol mixtures inside capillary porous plates

Isothermal vapor-liquid equilibrium (VLE) of ethanol-water mixtures at different temperatures and the isothermal VLE of acetone-ethanol mixtures at 305.15 K were experimentally measured in three different macroporous plates: a 13.5-mum pore diameter sintered stainless steel plate, a 30-mum pore diameter porous carbon plate, and a 30-mum pore diameter porous Teflon plate. The experimental results showed that the VLE of the ethanol-water system in the porous sintered stainless steel plate was dramatically altered, and the azeotropic point was shifted from ethanol mole fraction of 0.90 to > 0.99. However, there was no significant effect of this plate on the acetone-ethanol system. The effect of either the porous Teflon plate or the porous carbon plate on the VLE was insignificant for both systems. These results show that for substantial alteration of the VLE binary mixtures, two conditions are required: the liquid components must be of different polarity, and the porous plate should possess high polarization.