RECOVERY OF BICYCLIC AROMATICS FROM LIGHT CYCLE OIL BY. LIQUID-LIQUID EXTRACTION

Abstract

A lot of valuable bicyclic aromatic components, including 2, 6-dimethylnaphthalene (2,6 DMNA), are usually present in some refinery streams such as light cycle oil (LCO). In this work, the separation of naphthalene, a bicyclic aromatic component, by solvent extraction method from a model oil (p-xylene, iso-octane and naphthalene) using furfural and NMP as solvent has been investigated. A four factor Box-Behnken design was used to study the individual and interactive effects of four main parameters namely paraffinic content in model oil (P/F): 0.7-0.8; solvent to feed ratio (S/F): 0.5-1.0; temperature (T): 20-40 °C; time (t): 1-3 h for furfural and 1-7 hr for NMP on yield and selectivity of naphthalene. Gas chromatography- mass ..speetriffnetry was carried to analyse the composition of raffinate and extract phase. Various polynomial models were fitted to chalk out the best model for the system. Pareto analysis of variance (ANOVA) and other statistical tests were performed to check the soundness of the model. Furfural was found to be a better solvent than NMP, both in terms of yield and selectivity. The operating conditions leading to maximum aromatic recovery have been optimized. It was found that P/F=0.7, S/F=0.5, Temperature=24.41°C and time=2.98 h for furfural and P/F=0.76, S/F=0.76, Temperature=21.93°C and time=4.07 h for NMP yield optimum extraction condition, with lowest possible solvent requirement.