GB454176A - Improvements relating to the separation of waxy constituents from hydrocarbon oils - Google Patents

Abstract

<PICT:0454176/III/1> In the de-waxing of oils, the oil is diluted with a solvent consisting of a mixture of at least two components, one of which is selected from the group, dichloro ethane, dichloro propane and the corresponding bromine or fluorine compounds, and the other from the group, dichlor ethylene, trichlorethylene, dichlor propylene, trichlor propylene, and the corresponding bromine or fluorine compounds, whereupon the mixture is chilled and the fraction rich in wax is separated. The process may be effected in a single stage, or preferably the fraction containing wax and some oil first separated is further diluted and chilled to a lower temperature. Residual oils, hydrogenated oils containing wax, and asphaltic residuals may be treated. Wax may be separated by filtration, sedimentation or by centrifuge in which both crystalline and amorphous waxes are removed. The diluent mixtures may contain benzol and also carbon tetrachloride, fluoride or bromide. Wax-containing oil is withdrawn from a tank 1 and passes to a chiller 5 to which 3 volumes of a solvent mixture of dichlorethane and dichlor ethylene are admitted from tanks 3, 4. Chilling may be effected by evaporation of part of the solvent to a temperature of 0 DEG to -10 DEG F. by slow or shock chilling. The chilled mixture containing separated wax passes to a mixer 6 where oil and solvent are added from a later stage. The mixture is then freed from wax in a centrifuge 7 of the type described in Specification 446,607 or 446,608, and the de-waxed oil is withdrawn through a pipe 8. The separated wax containing raw oil and solvent passes to a chiller 9 to which solvent is added through a pipe 10, and the mixture is fed to a centrifuge 11 preferably of the type described in Specification 418,939. Hard wax is removed through a pipe 12 and the oil solvent is either returned to the mixer 6 through a chiller 13, or distilled to recover solvent and oil. The dewaxed oil may be finally treated with acid or clay in the presence of a solvent. The Specification as open to inspection under Sect. 91 comprises also the subject-matter of Specification 456,122. This subject-matter does not appear in the Specification as accepted.