What is raffinate oil, and how does it differ from other naphtha cuts?

What is raffinate oil, and how does it differ from other naphtha cuts?
Raffinate is the non-aromatic residue left after solvent extraction removes benzene, toluene and xylenes from reformate or cracked gasoline. Because light aromatics and near-carbon-number non-aromatics boil within fractions of a degree, distillation alone cannot separate them; liquid-liquid extraction with sulfolane or glycol ethers is required. One refinery practice uses sulfolane, exploiting the density gap between rich solvent (1.1-1.2) and raffinate (about 0.78). The raffinate water wash tower keeps sulfolane below 15 ppm, and non-aromatics in the solvent are held under 2000 ppm, often below 1000 ppm. This makes raffinate a low-aromatic, paraffinic stream, chemically distinct from straight-run naphtha and valued as cracker feedstock.