ABSTRACT
Re-refining involves essentially a second attempt at refining a feedstock that has excellent potential for use as base stock for formulating either automotive or industrial lubricants. The re-refining process will therefore vary to some degree with the feedstock or used oil that one is attempting to reclaim. The pretreatment step includes a number of simple options to remove unwanted contaminants from the used oil. In the more traditional re-refining process to produce high quality base stocks, all of the water and light boiling materials must be initially removed from the used oil feed. Developments in catalyst and hydrofinishing technology have identified advanced alternatives for the re-refining industry where some degree of base oil conversion can occur. The classification of re-refined base stocks is defined according to the guidelines that have been set out by the American Petroleum Industry and its API 1509 document.
