Re-refining used lubricating oil

• Main Author: Ng, Yui Ming.
• Other Authors: Dong Zhili
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Materials::Ceramic materials
• Online Access: http://hdl.handle.net/10356/35660
• Institution: Nanyang Technological University

Oil supply in the world is finite. It would more environmentally friendly if oil could be re-refined. Current lubricating oil re-refining involves energy intensive process. In this research project, two processes that are less energy intensive, flocculation and adsorption, were studied. For flocculation, Tetrapropylammonium hydroxide (TPAOH) was used as a flocculation. It was found that adding more TPAOH would not guarantee better results. If too much TPAOH was added, the sludge would turn watery making separation from oil difficult. The optimum amount was 5% which would result in the best viscosity of oil. Also, heating TPAOH with oil to 150 0C for 1 hour would accelerate the sludge forming process from 300 hours to 48 hours. For adsorption, alumina (Al2O3) and commercial clay (BCEF) were used and compared. The adsorption results for Al2O3 were better than BCEF. Adsorption process for both adsorbents were temperature dependent and were noticeable only above 70 0C. Acid treatment had no effect on the structure and surface area of Al2O3 and BCEF. Finally, the cleanness of the oil was found to be proportional to the amount of adsorbents used. Thermodynamic analysis was used to determine the energy involved. Future works could be conducted in the direction of cleaning up the used Al2O3 as well as anodizing Al2O3 to increase the surface area before the adsorption process. Finally computer simulations could be used to predict the optimum conditions for both processes.