In the present study, removal of sulfur and aromatic compounds from straight-run gas oil (SRGO), light cycle oil (LCO), coker gas oil (CGO), and their mixture, termed as mixed gas oil (MGO), was studied using N-methyl-2-pyrrolidone (NMP) solvent in a single-stage batch extractor and continuous countercurrent packed-bed extraction column. The effect of the extraction temperature (T E ), solvent/feed ratio (S/F), and antisolvent concentration (W c ) on the degree of sulfur removal (D sr ), yield of extracted gas oil (Y%), and performance factor (P f,α ), which combines both D sr and yield, was studied in a single-stage batch extractor. After optimization of the operating conditions for SRGO, LCO, and CGO in a single-stage batch extractor, studies on MGO were carried out in both a single-stage batch extractor and continuous countercurrent packed bed at estimated optimized values of T E , S/F, and W c . Issues related to the loss of valuable hydrocarbons with extract and value addition to extract hydrocarbon have been addressed in the present study by performing quantitative evaluation of distillate products from processing of the pseudo-raffinate (generated from the extract phase using antisolvent) in hydrocracker and fluidized catalytic cracking (FCC) processes. The present study also demonstrates the approach for improving the quality of extract as a carbon black feedstock (CBFS). The benefits and befitting of disposal of extract hydrocarbon in a delayed coker as a blending stream with vacuum residue (VR) is also discussed in detail.

No abstract

Activity coefficients at infinite dilution (γi ∞) offer a valuable tool for solvent selection in extraction processes. In this study, the γi ∞ values for solutes like alkanes, aromatics, and naphthenes in solvents, i.e., ionic liquids N-butyl-4-methylpyridinium tetrafluoroborate [BMPy]­[BF4], 1-butyl-1-methylpyrrolidinium bis­(trifluoromethylsulfonyl)­imide, [BMPyr]­[NTf2], and 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM]­[BF4], were estimated using gas–liquid chromatography at temperatures 313.1, 333.1, and 353.1 K. Partial molar excess enthalpies at infinite dilution (ΔH 1 E,∞) were evaluated from the γi ∞ values. The selectivity for the toluene/n-heptane system was also calculated from the experimentally observed γi ∞ and compared to the literature values for well-established industrial solvents sulfolane and N-methyl pyrrolidone.