Toward energy-efficient extraction of aromatics from light cycle oil using deep eutectic solvents: Insights from experimental and process evaluation

Efficient separation of aromatics and alkanes in light cycle oil (LCO) is critical for upgrading LCO into high-value chemicals; however, the energy costs of the entire extraction-regeneration process, influenced by LCO composition and extractant selection, remain inadequately explored, thereby limiting the economic viability of LCO upgrading. In this work, the influences of aromatic structure and composition in both raw and hydrotreated LCO on extraction, regeneration, and process energy consumption were systematically investigated. Two levulinic acid-based deep eutectic solvents (DESs) were employed as benchmark solvents. Liquid-liquid equilibrium experiments demonstrated that diaromatic-rich LCO significantly enhances extraction efficiency compared with monoaromatic-rich feeds. Process simulations further confirmed that diaromatic-rich LCO reduces total energy consumption by ∼23.3 % compared with hydrotreated LCO using TBPB:LEA (1:4). Both DESs can achieve ≥98 % aromatic purity and recovery; however, TBPB:LEA (1:4) favors energy savings owing to its higher distribution coefficient (up to 0.665 for 1-methylnaphthalene and 0.219 for tetralin), whereas TPAB:LEA (1:4) is preferred when higher aromatic purity (≥99 %) is required due to its higher selectivity (up to 539 for 1-methylnaphthalene and 208 for tetralin). These findings offer valuable guidance for optimizing feedstock and solvent selection strategies toward energy-efficient separation of aromatics and alkanes during LCO upgrading.