Separation of polycyclic aromatic hydrocarbons by solvent screening assisted extractive distillation from FCC diesel

doi:10.1016/j.cjche.2025.09.001

Abstract

Abstract: The oversupply of diesel in China necessitates efficient separation of polycyclic aromatic hydrocarbons from fluidized catalytic cracking diesel for value-added utilization. However, purification is hindered by alkane and monocyclic aromatic interference. In this work, we propose a solvent-screening strategy for extractive distillation based on molecular polarity and interaction energy analysis. Quantum chemical calculations identified ethylene glycol (aromatic solubility) and N,N-dimethylformamide (alkane selectivity) as optimal solvents, with weak hydrogen bonds (e.g., O-H…π, C-H…π) governing aromatic interactions. Two process designs were developed: (1) solvent extraction followed by primary extractive distillation (purity >95.0% (mass)) and (2) direct two-stage extractive distillation (purity >92.0% (mass)). This work provides a flexible framework for polycyclic aromatic hydrocarbon separation tailored to market demands while elucidating solvent-solute interactions at the molecular level.

Key words: Polycyclic aromatic hydrocarbons, Extractive distillation, Solvent screening, Quantum chemical calculation

摘要： The oversupply of diesel in China necessitates efficient separation of polycyclic aromatic hydrocarbons from fluidized catalytic cracking diesel for value-added utilization. However, purification is hindered by alkane and monocyclic aromatic interference. In this work, we propose a solvent-screening strategy for extractive distillation based on molecular polarity and interaction energy analysis. Quantum chemical calculations identified ethylene glycol (aromatic solubility) and N,N-dimethylformamide (alkane selectivity) as optimal solvents, with weak hydrogen bonds (e.g., O-H…π, C-H…π) governing aromatic interactions. Two process designs were developed: (1) solvent extraction followed by primary extractive distillation (purity >95.0% (mass)) and (2) direct two-stage extractive distillation (purity >92.0% (mass)). This work provides a flexible framework for polycyclic aromatic hydrocarbon separation tailored to market demands while elucidating solvent-solute interactions at the molecular level.

关键词: Polycyclic aromatic hydrocarbons, Extractive distillation, Solvent screening, Quantum chemical calculation

Jun Li, Wanting Yu, Jinsen Gao. Separation of polycyclic aromatic hydrocarbons by solvent screening assisted extractive distillation from FCC diesel[J]. Chinese Journal of Chemical Engineering, 2025, 87(11): 89-102.

Jun Li, Wanting Yu, Jinsen Gao. Separation of polycyclic aromatic hydrocarbons by solvent screening assisted extractive distillation from FCC diesel[J]. 中国化学工程学报, 2025, 87(11): 89-102.

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