GB486317A - Method of and apparatus for the continuous steam distillation of high boiling point liquids - Google Patents

Abstract

<PICT:0486317/III/1> <PICT:0486317/III/2> In the steam distillation of high boiling liquids, such as fatty acids and glycerine, in two or more serially arranged stages, in at least one of the stages a multiple of the quantity of liquid continuously introduced into the still per unit period is circulated therein and forced up above the surface of the liquid, a portion of the upwardly forced liquid being diverted to the next distillation stage. In a suitable still in which the second distillation stage is effected in an upper annular chamber i, the still is provided with a depending pipe f surrounding a circulation open-ended tube d, which extends into the vapour space of the still, a part of the liquid forced up the tube d by steam admitted at e being trapped by a funnel k and supplied to the chamber i. Each of the stages is both directly and indirectly heated, by perforated pipes g, p and coils c, o respectively. The liquid may be re-cycled to the main still via pipe l and valve s. A number of similar two-stage stills 2, 3, 4 and 11, Fig. 3, may be used in succession in a plant, the stills being connected by feed pipes 8, 9 and 10. Only one of these stills may be of the described type, the others being single-stage stills; the final apparatus 11 may be a condenser in which case the circulation tube is provided with a stirring member 13 and the heating coils replaced by a cooling coil 12. Each of the vessels are connected to a vacuum condenser by pipes 15. In a modification of the invention the two stages of the still are coterminous the liquid of the second stage falling on the surface of the liquid in the first stage a trap being used as before where the liquids meet. Each of the double-stage stills may be connected to a condenser, particularly where fractional distillation is required, as in the separation of the fatty acids in animal and vegetable oils and fats.