Up-gradation of light cycle oil using solvent extraction route

Sulphur compounds naturally exist in crude oil and in the oil refinery, various fuel fractions distributed according to their boiling points. Diesel is a significant transportation fuel and made up of various refinery streams like straight run gas oil, light cycle oil, coker gas oil, etc. Light cycle oil (LCO) is rich in aromatics especially polyaromatics, e.g., alkylated naphthenes, etc. as well as refractory sulphur compounds e.g., dibenzothiophene etc. It may not be possible to reduce aromatics through hydrogenation and sulphur compounds through hydrodesulphurization. Both are expensive and releases more greenhouse gasses. Hence, alternative methods are gaining importance among which solvent extraction has attracted worldwide attention due to inherent advantages like mild reaction conditions and low cost. In this article, LCO has been distilled up to and above 250°C fractions. Extraction of LCO 250°C+ fraction with solvents, aqueous NMP and nitro methane have been carried out using various solvent to feed ratio and achieved polyaromatics reduction from 23.0 % to < 5.0 % and low sulphur < 0.3wt%. Thus process avoids hydro treating step for meeting PAH specifications.