Patent GB-355294-A (GB)
Title: Process for splitting up a mixture of liquids into its components
IPC: C10G21/04
Filed: 1930-05-21
Abstract: Mineral oils or other liquid mixtures are separated into their components, or into desired groups of components, by the action of two auxiliary liquids flowing in countercurrent; the auxiliary liquids are mutually immiscible or only slightly miscible, and each has different solvent properties for the components to be removed from the mixture.  Lubricating oils may be fractionated by treatment with benzine and liquid sulphur dioxide, and middle oils by methyl alcohol and carbon bisulphide.  In an example, a mixture of equal volumes of mineral oil and naphthenic acids was treated with alcohol and petrol, the rate of flow of alcohol being 3 times that of petrol; the alcohol yielded naphthenic acids containing 2 per cent of oil, and the petrol yielded oil containing 2 per cent of acids.  Further treatment of this oil with the same solvents, using 10 <PICT:0355294/III/1> <PICT:0355294/III/2> <PICT:0355294/III/3> times as much alcohol as petrol yielded two fractions containing respectively 80 and 35 per cent of sulphonatable bodies.  The process may be carried out continuously or the oil &c. may be treated in batches.  The auxiliary liquids may have the same or different specific gravity, and one of them may be miscible with the oil &c. or may be a component of it.  As shown in Fig. 1, the oil &c. is introduced at R, R into a horizontal conduit divided by a diffusion membrane M, and the auxiliary liquids A, B which may be of the same specific gravity flow in opposite directions along the two parts of the conduit.  As shown in Fig. 2, the liquids A, B flow through a tower S, the liquid B being the heavier; the oil &c. R is introduced continuously at an intermediate point and is split by the solvent action into components R, R2; the auxiliary liquids A, B drawn off at the opposite ends of the tower contain the respective components R, R2 and are separated therefrom by distillation, by freezing &c. and are re-circulated. As shown in Fig. 3, a batch of oil &c. R, which may be mixed with one auxiliary liquid C, is circulated from a reservoir E transversely through the auxiliary liquids C, D flowing in countercurrent through the tower S; the liquids C, D leaving the ends of the tower contain components R1, R2 of the oil &c. until one of the components, say R1 is exhausted, the circulation is continued until the other component R2 is completely removed by the liquid D from its solution in the liquid C.  During the process, the liquids C, D are recovered from their mixtures with R1, R2 and re-circulated. In a modification of this batch process, the liquid R + C is circulated to and from points near the bottom or top of the tower ; if at the bottom, a mixture R2 + D is drawn off at the top, and a portion of the liquid at the bottom, consisting of C + R, +R2, is drawn off continuously, distilled or otherwise separated into C and R1 + R2, and these components returned to the top and bottom of the tower.  The concentration of R2 in the reservoir continually decreases, and the process is stopped when the component R2 has been completely removed.