Abstract: Methods of processing used oil vacuum tower bottoms in a heated chamber. The used oil vacuum tower bottoms are introduced into the chamber as a liquid. The used oil vacuum tower bottoms are introduced in a first section of the heated chamber. The used oil vacuum tower bottoms pass along the length of the chamber through a series of sections that are each heated to different temperatures. The sections may have varying lengths and may be heated to a variety of different temperatures. As the used oil vacuum tower bottoms progress along the length of the chamber, hydrocarbons are removed resulting in an outputted product that is substantially free of hydrocarbons and that has a substantially granular form. Vapor from the process is further captured producing vacuum gas oils.

Abstract: Methods and systems of removing color bodies from vacuum gas oil. The methods and systems include mixing the oil and N-Methyl-2-pyrrolidone (NMP) within one or more columns. After moving through the one or more columns, water and glycerin are added to the oil. A second portion of the NMP is removed from the oil as well as at least some of the water and at least some of the glycerin through at least one centrifuge.