Used lubricating oil is a valuable resource, but it can be an environmental problem and a financial liability if improperly disposed of. Used oils pose hazards to human health and the environment, and therefore need to be managed safely. The mismanagement of used oil can contaminate air, water and soil. The objective of this work is to investigate the re-refining of used lubricating oils using solvent extraction process. The characteristics of used lubricating oils, utilization methods, elimination methods, environmental and human health effects were reviewed. Also, the various re-refining processes were described and a comparison between them was made to indicate the advantages and disadvantages of solvent extraction process. Experiments were carried out on used oils collected from several service stations. Used oils were subjected to preliminary treatment to remove water and dust followed by solvent extraction of base oil using different classes of solvents including alcohols, ketones and hydrocarbon solvents. Bench scale study was carried out to investigate the effect of different variables.

Ahmed Samir Gabrah, studied master of science in chemical engineering at faculty of engineering, Alexandria University. Section head at Alexandria Petroleum Company (APC), Alexandria, Egypt.