GB714933A - Improvements in or relating to the fractional distillation of liquid mixtures - Google Patents

Abstract

Liquid mixtures are submitted to continuous fractionation by passing the liquid through a series of consecutive vaporization stages arranged in two separate units, the feed being introduced into one of the stages of the first unit, the vapours evolved in the stages of the first unit (stages 1 to 9) are combined and introduced into a rectifying column 23, the vapours evolved in the stages of the second unit (stages 10 to 12) are introduced into a partial condenser 26, the vapours leaving the partial condenser being introduced into the rectifying column together with the vapours from the first unit; the bottoms withdrawn from the column are fed to the first stage of the first unit, the condensate from <PICT:0714933/III/1> the partial condenser is fed into one of the stages of the first unit, the residual unevaporated liquid is withdrawn from the last stage of the second unit, and the light fractions are withdrawn from the top and side of the column. The feed liquid is supplied to the vaporization stage (stage 4) containing liquid wherein the concentration of the light fractions is equal to that in the feed liquid; and the condensate withdrawn from the partial condenser is also introduced into the appropriate vaporization stage (stage 8) with respect to the concentration of the light fractions. The main and secondary chambers of the still 13 are separated from each other by partition 16, the various compartments being connected by openings 15 so that they are all filled with liquid to the level of overflow 28. The compartments may alternatively be arranged in the form of a circle. The liquid withdrawn from the last vaporization stage may itself be fractionated in a plant similar to that described. The plant is especially advantageous for the steam distillation of higher fatty acids (higher than C16) in high vacuum.