200 Refining Used Lubricating Oils
Figure 7.15 shows the schematic ow diagram for the Revivoil process as described
by Fehrenbach (2005) and Audibert (2006) has presented similar diagrams. The incom-
ing used oil is heated to 140°C (285°F) and enters the vacuum distillation column where
water and light ends are ashed off. The oil stream then enters the TDA column where it
is distilled at 360°C (680°F) to produce three side cuts of base oils, an intermediate gas
oil overhead product, and a residue of asphaltic material. The side cuts are stored to be
separately processed in a hydrotreater operating at a high pressure of 100 bar (10MPa;
1450psi) with a catalyst chosen to favor the reaction with the unsaturated compounds
of sulfur and nitrogen. ...