GB476610A - Fractional separation of crude hydrocarbon oil - Google Patents

Abstract

<PICT:0476610/III/1> Crude hydrocarbon oils are separated into fractions by fractional distillation by adding to the crude oil in succession a number of carrier substances of known boiling point in order of magnitude of their boiling points, beginning with the lowest boiling-point substance, the series of carrier substances being selected so that each has a boiling point below the temperature at which the fraction to be collected would distil without the presence of the carrier substance and a vapour pressure at the desired distillation temperature sufficient to bring the total vapour pressure at that temperature of carrier substance and fraction to be collected up to the pressure in the still, distilling the mixture after the addition of each carrier and collecting the distillate until the boiling point of the carrier is reached and only the carrier comes over; whereafter the next carrier of the series is added and the procedure repeated. The carriers can be added in the vapour or liquid state and the distillation can be carried out under reduced pressure. The collected fractions can be separated from the carriers carried over therewith (1) mechanically when the fraction and carriers are immiscible, (2) by distillation when miscible. In an example the carriers used successively are hexane, decane, naphthalene, bromonaphthalene, and benzophenone. A still 1 provided with a stirrer 2 and a heating coil 3 is filled with the oil to be distilled. After air has been removed hexane from a container 5a is heated to boiling point in a coil 7 and then run into the still. The still is then heated until the lowest fraction and the carrier distil over, the distillate being condensed in the cooler 9 and collected in a receiver 10a. The remaining carriers are then added successively from the containers 5b, c, d, e, and the corresponding distillates collected in the receivers 10b, c, d, e, respectively.