White Oils Hydrotreatment
In order to produce white oils from the existing base oils of the refinery, it is necessary to completely hydrogenate aromatic structures into naphthenic ones. When the objective is technical-grade white oils, a one-step process is required, that uses a catalyst and a configuration close to that of hydrofinishing for motor base oil production. The difference concerns operating conditions, as the high reduction in aromatics content and the quasi total elimination of sulfur and nitrogen compounds require a high hydrogen partial pressure, a low space velocity and a low temperature. When the objective is medicinal-grade white oils, a second step is necessary after that required for technical-grade products, in particular to completely eliminate polycyclic aromatics. In all cases, those white oils comply with BGA, FDA and CODEX quality specifications.