GB707468A - Method of and apparatus for treating liquids with gases or vapours - Google Patents

Abstract

The liquid in a vessel or still, e.g. oils, waxes or resins to be deodorized, fatty acids, oils &c. to be distilled or paraffins to be oxidized with air, is continuously circulated by a plurality of gas or vapour uplift pipes or other conduits which discharge liquid at different heights in the vapour space of the still. This destroys the foam and prevents carry-over of liquid with the vapours. The still of Fig. 1 is provided with two concentric uplift pipes 2, 3, the outer terminating <PICT:0707468/III/1> <PICT:0707468/III/2> short of the inner at each end and both extending above the liquid level at their upper ends and below the liquid level at their lower ends. Pipes 5, 6 for introducing gas or vapour, e.g. steam, into the uplift pipes are provided and baffles 7, 8 for deflecting the discharged liquid into the form of a curtain falling back to the bulk of the liquid. The pipe 3 may be divided longitudinally or a plurality of pipes used. A heating coil 12, which may also be used for cooling, and a steam or air distributer 13 are also provided. In the vapour space is a liquid-vapour separator 9, 10, trapped liquid draining to a gutter 11. The apparatus of Fig. 2 (not shown) is similar to that of Fig. 1, but a mechanical stirrer is provided, the baffles are differently arranged and the liquid-vapour separator is as shown in Fig. 3. The stirrer may also rotate the uplift pipes or baffles, imparting a rotation to the liquid. In Fig. 3, in addition to the central uplift pipes 40, 45, an annular uplift passage 52 is provided to which steam is supplied by pipe 48. Heating (or cooling) coils 49, 50 are provided and a steam distributer 51. The central uplift uplift pipe 40 depends into a well 41. The discharge from pipes 40, 45 is deflected by baffles 43, 47 and falls on to the liquid rising out of the passage 52 or on to an annular guide surface 53 from which it is returned to the main body of liquid. The outlets from the steam distributer 51 may be arranged to give a rotary motion to the liquid in the still. The vapour off-take 54 and cover 55 of the still may be jacketed, the jacket being evacuated for insulation or a cooling agent circulated therein. The part 56 of the vapour separator 56, 58 may be similarly jacketed to insulate the spaces above and below the part 56. In examples: (1) ground-nut oil is deodorized in the apparatus of Fig. 1 by vacuum steam distillation of the undesired constituents, circulation being effected also by steam. The oil is then cooled to 50-80 DEG C. by coil 12. (2) Partially purified ground-nut oil is deodorized in the apparatus of Fig. 3 by steam distillation at 150 DEG C. and 5 mm. pressure for 2 hours. The oil is cooled to 110 DEG C. and run off to a second vessel where it is further cooled under vacuum.