Selective Extraction of Aromatics from Slurry Oil with Subcritical Water

Area of Science:

• Chemical Engineering
• Green Chemistry
• Petroleum Refining

Background:

• Slurry oil (SLO), a byproduct of fluid catalytic cracking, presents challenges in aromatic separation.
• Developing efficient and sustainable methods for SLO valorization is crucial for the petrochemical industry.

Purpose of the Study:

• To investigate subcritical water (Sub-CW) as a green solvent for selective aromatic extraction from SLO.
• To characterize the extracted aromatics and understand the separation mechanism.

Main Methods:

• Utilized a semi-batch system with subcritical water at temperatures ranging from 250-325 °C.
• Employed techniques including simulated distillation, SARA analysis, FT-IR, and 1H-NMR for characterization.
• Performed principal component analysis of Hansen solubility parameters to analyze molecular interactions.

Main Results:

• Achieved a 16 wt% extract yield at 325 °C and a 6:1 water-to-oil ratio.
• The extract comprised over 90 wt% aromatic hydrocarbons, primarily 3- to 4-ring polycyclic aromatic hydrocarbons.
• Demonstrated selective enrichment of aromatics and effective separation from saturates and asphaltenes.

Conclusions:

• Subcritical water exhibits tunable selectivity for aromatic hydrocarbons from SLO.
• The solubility order in Sub-CW is aromatics > cycloalkanes > alkanes, influenced by temperature.
• This study provides insights for designing subcritical solvents and intensifying SLO valorization processes.