| 摘要 |
Paraffinic hydrocarbons are separated from hydrocarbon oils by mixing a hot solution of urea containing 10-40 volume per cent water (the amount of water in the solution being less than that present in a saturated aqueous urea solution at the temperature desired for adduct formation) with the oil together with an oil solvent having a boiling point not higher than the temperature desired for adduct formation; the temperature of the mixture is controlled by evaporating a part of the solvent while vigorously agitating the mixture and the granular adduct formed between part of the hydrocarbons and urea is separated and decomposed. Oil solvents referred to are hydrocarbons, e.g. butane, pentane and pentadiene and fluorinated or chlorinated hydrocarbons, e.g. methylene chloride of which 50-200%, per volume oil, may be used. The adduct may be separated from the mixture by settling, sieving or filtration and then decomposed by heating above 70 DEG C., by adding hot aqueous methylene chloride recovered from the urea separated from the adduct, and heating both indirectly and by introduction of steam. The urea recovered from the decomposed adduct is concentrated and reused. In the example, paraffin wax is separated from spindle oil using a 30% aqueous solution of urea (saturated at 70 DEG C.) and methylene chloride as oil solvent.ALSO:Paraffinic hydrocarbons or hydrocarbon derivatives thereof are separated from hydrocarbon oils by mixing the oil with a hot aqueous urea solution (containing 10-40% by volume of water, the amount of water in the solution, however, being less than that present in a saturated aqueous urea solution at the temperature desired for adduct formation) and with an oil solvent (having a boiling-point not higher than the temperature desired for adduct formation), vigorously agitating the mixture to bring it to and maintain it at the temperature desired for adduct formation by heat exchange between the hotter and cooler liquids and by the abstraction of heat caused by evaporation of part of the oil solvent, separating the granular adduct formed, removing solvent from the oil solution, and decomposing the adduct into paraffinic hydrocarbons or derivatives thereof and urea solution. Oil solvents referred to are hydrocarbons (e.g. butane, pentane or pentadiene) and fluorinated or chlorinated hydrocarbons (e.g. methylene chloride). The oil solvent evaporated from the mixture may be condensed and re-used, while the urea solution obtained by decomposition of the adduct may also be re-used.
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