Removal of refractory sulfur and aromatic compounds from straight run gas oil using solvent extraction

Abstract

In the present study, extraction of sulfur and polyaromatic impurities from actual straight run gas oil (SRGO) containing 1.3 wt% sulfur was studied using various solvents such as acetonitrile, N,N-dimethylformamide, furfural, N,N-dimethylacetamide and dimethyl sulfoxide. Effects of water as antisolvent, extraction conditions and types of extraction operation (batch, single and multi-stage and continuous) have been studied. Performance of solvent extraction process, which is governed by the degree of sulfur removal (D_sr) and yield of extracted SRGO (ESRGO), has been evaluated in terms of a performance factor (P_f,α), which has been defined in terms of weight factor (0 < α < 1) as: P_f,α = αD_sr + (1 − α) yield. DMF was found to be a better solvent in terms of P_f,α and regeneration ability. The possibility of utilization of extract as carbon black feed stock (CBFS) has also been discussed based upon the calculated bureau of mines correlation index (BMCI) values.