Efficiency of mass transfer trays with allowance made for nonequimolar counterdiffusion

An analysis of experimental data on the distillation of methanol-water, ethanol-water, and water-acetic acid mixtures is performed. A considerable difference in the efficiency of separating a water-acetic acid mixture and aqueous alcohol solutions is noted. This phenomenon is explained by the difference in the heats of evaporation of components of the studied mixtures and the associated nonequimolar counter-diffusion. Taking into account nonequimolar counter-diffusion made it possible to describe the dependence of mass transfer coefficients by a unified equation for all of the studied mixtures.