Re-refining of used lubricating oil

Abstract

Small amount pure lubricating oil can pollute major amounts of water eg: groundwater as well as the land on which it is spilled. Used engine oil itself contains a number of additives and is contaminated by impurities and residues resulting from the combustion process. Some of them are poisonous and carcinogenic like lead and PAH (poly-aromatic hydrocarbons). Also the oils used in transformers contains PCBs (polychlorinated biphenyls), which are highly carcinogenic as well. From various sources such kind of used lubricating oils are generated and are disposed improperly. The burning of used oil in kilns and incinerators produces lots of ash and carcinogens causing environmental pollution. Waste lubricating oil is a resource that cannot be disposed of randomly due to the presence of pollutants. In response to economic problems and environmental protection, there is a growing trend to regenerate and reuse waste lubricants. By proper recovery and refinement of it, a lot of valuable product can be obtained. The objective of re-refining is to remove the degraded additives and contaminants and to restore the properties of the oil identical to the standards provided by SAE (Society of Automobile Engineers).