METHOD FOR HYDROTREATING USED OILS

26982-31 A method for hydrotreating used oils to second raffinates in the form of lubricating oils is provided wherein ecologically undesired byproducts or wastes are avoided without requiring expensive separating steps or reaction conditions or the use of costly catalysts. In particular, with this process highly contaminated used oils, i.e. those having organochlorines, particularly PCB, chlorinated dioxins and dipherylene oxides, in concentrations above a certain limit, are likewise again usable as a second raffinate, particularly as lubricating oil; thus, they must no longer be destroyed, for example, in a high temperature incineration process. For this purpose the used oil is first of all merely freed from coarse solids and subsequently with the addition of hydrogen subjected to liquid-phase hydrogenation at pressures of preferably 150 bar and temperatures of preferably 350.degree.C. Thereafter, the reaction products are separated into the lubricating oil and in particular solids-bearing byproducts.