GB649583A - Improvements in or relating to the treatment of liquids with adsorptive solids - Google Patents

Abstract

<PICT:0649583/III/1> <PICT:0649583/III/2> Removal of one or more constituents from a liquid with an adsorptive solid is carried out in an apparatus comprising a vessel having a liquid inlet in its upper portion and a liquid outlet in its lower portion, two horizontal perforated plates placed one above the other across the inside of the vessel, a multiplicity of vertical tubes filled with adsorptive solid extending between the plates and secured in corresponding perforations, and means for heating the external surfaces of the tubes. As shown in Fig. 1, adsorptive solid is fed through a compound cone disperser 21 into a vessel 11, and flows into tubes 16, mounted between plates 17 and closed at their lower ends by a filter pad 18. Sufficient is added to give a layer 1 inch thick above the full tubes, when compressed by compressed air introduced through a conduit 24. Liquid to be treated, dissolved in a suitable solvent, is introduced from a mixing tank through a conduit 25 up to a level AA. The liquid is then forced through the column 16 by compressed air from conduit 24. Liquid effluent is run off to a still through conduits 29 and 30. The solid is then washed with a volume of solvent introduced through an inlet 26 twice that originally passed, stripped by a stripping solvent from an inlet 27, the strip solution obtained being passed along conduits 29 and 31 to a separate still, dried by steam circulated round the columns from an inlet 37 and an outlet 38, and finally cooled by water passing from an inlet 39 to an outlet 40, air being blown through the solid and leaving by a cock 34 during the last two operations. If the solid can be used for only a single treatment, it is dried and removed after the washing step. In Fig. 2, four vessels 51 of Fig. 1 type are arranged in parallel having a common mixing tank 53, vacuum pump 54, and compressor 55. The purified liquid solvent mixture is received in a tank 56, or stills 57, from which pure liquid, if of higher boiling point than the solvent, is withdrawn at 61, and solvent via condenser 58 and water trap 59 to tank 60. Stripping solvent passes to a still 62, condenser 63, and tanks 64, or, if it contains or consists of the solvent for the liquid to be purified, partially or wholly to tank 60. In one example 267 lbs. of an oil containing 100,000 international units per gram of vitamin A is dissolved in petroleum ether (B.P. 60-80 DEG C.) to a volume of 10 gallons, and the solution run through an apparatus consisting of 241 tubes each 3 feet long and 1 1/2 inches internal diameter packed with and covered up to 1 inch by a total of 561 lbs. activated gamma alumina. Washing is effected with 40 gallons of the same solvent, yielding 6.6 lbs. oil containing 95 per cent of the vitamin. The 20.1 lbs. oil retained on the column is stripped with 133 gallons of a liquid mixture comprising 85 per cent petroleum ether and 15 per cent ethyl alcohol, and the strip solvent distilled to separate the oil. In another example plant for drying palm oil consists of four units each comprising ten tubes each having an internal diameter of 1 1/2 inches and a length of 10 feet packed lengthwise in diamond spacing into a 12-inch diameter casing 12 feet in length. 12 inches above each tube-plate is allowed for header and receiver respectively. The tubes are packed with an acid-free silica gel, and the units connected in series, three being operated while the fourth is revivifying. The adsorbent may be a common one, or an organic material such as sucrose.