Process for Producing High-Value Aromatics from Light Cycle Oil Using a Solvent Extraction Method

Light cycle oil (LCO) is a low-quality and poorly marketable byproduct of a fluidized catalytic cracker (FCC) in a typical petroleum refinery and contains valuable aromatic components. The present work investigates the extraction of diaromatic components from LCO using solvents such as nitromethane, n-formyl morpholine, dimethylformamide, dimethyl sulfoxide, and n-methyl-2-pyrrolidone. The experimental work indicated that dimethyl sulfoxide showed better results in terms of a high aromatic distribution coefficient and diaromatic recovery value. Because of its better performance and lesser toxicity compared to conventional solvents such as n-methyl-2-pyrrolidone, dimethyl sulfoxide is an ideal candidate for the solvent extraction process. Further, extraction parameter optimization (varying the solvent-to-feedstock ratio and extraction temperature) was also performed with the dimethyl sulfoxide solvent and light cycle oil feedstock obtained from a refinery. The raffinate and extract products were characterized using different techniques such as Fourier-transform infrared spectroscopy, 1H and 13C nuclear magnetic resonance, and gas chromatography mass spectrometry (GC-MS) for detailed hydrocarbon compositional analysis. The GC-MS characterization results of the extract hydrocarbons showed the presence of naphthalene derivatives (mainly 1-methylnaphthalene and 2,6-dimethylnaphthalene). Therefore, the aromatic rich extract product obtained after the extraction experiments can be further used as a valuable precursor to the feed stream in the hydrocarbon industry.