Optimization of waste lubricating oil regeneration using acid‐clay process

Abstract Waste lubricating oil is non‐biodegradable materials. It is released into the environment and its disposal has become a global environmental issue due to its impact on all life aspects. The production of waste lubricating oil has recently increased rapidly. The aim of this work is to recover, optimize oil production process from waste lubricating oil. This was investigated using the acid‐clay process. Response Surface Methodology (RSM) approach was used to optimize the desludging reaction. The studied parameters were acid to oil ratio, contact time, temperature. The mixing ratio of acid to waste oil were selected in the range of 1:10 to 2:10 (v/v). Reaction time was in the range of 60–120 min. The predicted maximum viscosity index of 117.54 was obtained at the temperature of 40°C, 20% acid to oil ratio, and reaction time of 60 min. The results were assessed experimentally using five runs and the average value of viscosity index was 111.76 with standard deviation of 0.739 and error 4.91%. The samples obtained at optimum conditions were characterized by measuring flash point at 180°C, carbon residue of 0.487, kinematic viscosity at 100°C of 17cSt, the water content of 0.01%, ash content of 0.02%. Viscosity index of was found in complies with the Egyptian standards.