Simulation and optimization of aromatic extraction from lube oil cuts by liquid-liquid extraction

The simulation and optimization of aromatic extraction process from lube oil cuts using furfural as a solvent are conducted by linking the Aspen Plus simulator and MATLAB. The standard ASTM experiments are performed for determining density, refractive index, and viscosity of oil cut to apply the pseudo-component approach. The NRTL model was used for modeling the liquid-liquid equilibrium (LLE) of the system, and the binary interaction parameters (BIP) were determined by regression with the phase equilibrium data. The modeling results demonstrated that by increasing the solvent to feed ratio and the extraction temperature, the refractive index and the yield of raffinate phase decrease; however, the value of the viscosity index and total energy consumption of the process is increased. Finally, multi-objective optimization using an evolutionary algorithm is conducted to present the best trade-offs between the extraction efficiency, refractive index, and process energy consumption. Also, the single optimum point obtained from optimizing the linear combination of objective functions showed that the values of raffinate phase yield and refractive index are 30.77% and 1.449, respectively. However, the energy consumption of the process increases by about 20% compared to the base case.