Optimization of Asphaltenes Separation from Vacuum Distillation Residue using Liquid-Liquid Extraction by Response-surface Method

This investigation studied the separation of asphaltenes from the vacuum bottom, using industrial solvents such as normal pentane, hexane, and heptane. The central composite design (CCD) as a response surface methodology (RSM) method was applied to optimize the process. The weight percentage of asphaltene and the yield of de-asphalted oil (DAO) had been achieved at 0.447 and 48%, respectively, under optimum economic conditions (normal hexane solvent, solvent to feed ratio of 9.5 mL/g, and extraction temperature of 25 °C). The statistical study indicated that the response surface quadratic model for the mentioned parameters was significant and a perfect correlation between the statistical model and experimental data was found. Furthermore, according to an analysis of variance (ANOVA), the temperature of extraction and the quadratic interaction of the solvent to feed ratio parameter have shown a significant impact on the weight percentage of asphaltene. In general, the results suggest that the introduced approach is an efficient and economical technique to increase residual fluid catalytic cracking unit (RFCC) capacity and production of high-quality bitumen.