Process for working up used lubricants by hydrogenation.

摘要

Spent oils are processed by hydrogenation to give second raffinates in the form of lubricating oils. Ecologically undesired by-products or wastes are avoided in this process, without expensive separation steps or reaction conditions or the use of expensive catalysts being necessary. In particular, the result is that even highly contaminated spent oils, i.e. those which contain organochlorine compounds, especially PCB, chlorinated dioxines and dibenzofurans in concentrations above defined limits, can also be re-utilised as a second raffinate, especially as a lubricating oil; therefore, they no longer have to be destroyed, for example in a high-temperature combustion process. For this purpose, the spent oil is first freed only of coarse solids and then subjected, with addition of hydrogen, to hydrogenation in a liquid phase at pressures of preferably 150 bar and temperatures of preferably 350 DEG C; the reaction products are then separated into the lubricating oil and, in particular, solids- containing by-products.