GB434714A - Improvements in or relating to the separation of hydrocarbon mixtures - Google Patents

Abstract

<PICT:0434714/IV/1> Synthetic resins such as those obtained by polymerizing unsaturated aliphatic hydrocarbons or by condensing unsaturated with aromatic hydrocarbons, are treated with light hydrocarbon solvents whereby the resin is separated into two layers containing heavy and light fractions, and the heavy fraction is then further treated with the solvent at a lower temperature. Resin is drawn from a tank 30 and is forced into the top or the middle of a heat insulated extracting tower 37, provided with heating coils 38 maintained at progressively increasing temperatures from at the bottom 75 to 125 DEG F. below the critical temperature of the solvent to a temperature within 10 to 50 DEG F. at the top. The descending stream of resin is extracted at decreasing temperature with liquified propane which rises from openings 43 in a pipe connected to a storage tank 39. The lighter fraction passes through a pipe 44 to a still 45 in which solvent is removed and returned to the tank 39 leaving the resinous extract. The heavy fraction is drawn off at the bottom of the column 37 and may be filtered hot through charcoal or clay before removal of solvent in a still 52. In modifications of the process the extraction is effected (1) in separate stages of decreasing temperature in which the heavier fraction proceeds from one stage to the next and the lighter fraction is drawn off at each stage; (2) in separate stages of increasing temperature in which the lighter fraction proceeds from one stage to the next, the heavier fraction proceeds from one stage to the next preceding stage, and the heavy fraction at the first and the lighter fraction from the last stages are withdrawn. Methane, butane, ethane, pentane, propylene, butylene, ethylene, or amylene may replace propane as solvent.ALSO:<PICT:0434714/III/1> Heavy hydrocarbon oils such as lubricating oil are treated with a light hydrocarbon solvent, whereby the oil is separated into layers containing heavy and light fractions, and the heavy fraction is then further treated with the solvent at a lower temperature. Heavy oil is drawn from a tank 30 and forced into the top or middle of a heat insulated extracting tower 37, provided with heating coils 38 maintained at progressively increasing temperatures from at the bottom, 75 to 125 DEG F. below the critical temperature of the solvent to a temperature within 10 to 50 DEG of the critical temperature at the top. The descending stream of oil is extracted at decreasing temperatures with liquefied propane which rises from openings 43 in a pipe connected to storage tank 39. The light fraction passes through a pipe 44 to a still 45 in which solvent is removed and returned to the tank 39, leaving the light oil extract. The heavy fraction is drawn off at the base of the treating tower 37 and may be filtered while hot through charcoal, clay or other adsorbent before removal of solvent in a still 52. The resulting purified oil or the initial oil may be treated with aluminium chloride, acid or clay and extracted with phenol; hydrogenated; or treated with propane to remove asphalt and wax. In modifications of the process the extraction is effected (1) in separate stages of decreasing temperature, in which the heavier fraction proceeds from one stage to the next and the lighter fraction is drawn off at each stage; (2) in separate stages of increasing temperature, the lighter fraction proceeding from one stage to the next, through the stages in one direction and the heavier fraction in the opposite direction. Oils treated include heavy mineral oils, or cracking or destructive hydrogenation products thereof or of coal, tar, pitch, shale, lignite and bitumen. Methane, ethane, butane, pentane, ethylene, butylene, propylene or amyl may replace propane as solvent. The process may also be applied to the purification of waxes or synthetic resins such as those obtained by polymerizing unsaturated aliphatic hydrocarbons, or by condensing unsaturated hydrocarbons with aromatic hydrocarbons.