Abstract: Processes are disclosed for the separation of aromatic hydrocarbons from feedstreams containing mixtures of aromatic and non-aromatic hydrocarbons using extractive distillation with an aromatic selective solvent in order to separate the aromatic hydrocarbons from the non-aromatic hydrocarbons. A side stream comprising the aromatic hydrocarbons and trace amounts of entrained aromatic selective solvent is withdrawn from the extractive distillation column and passed to a cyclone separator to provide a lean solvent stream, a stream comprising the aromatic hydrocarbons. The raffinate is withdrawn as an overhead stream comprising non-aromatic hydrocarbons. Various solvents are disclosed and an especially preferred solvent is sulfolane.

Abstract: Processes are disclosed for the separation of aromatic hydrocarbons from feedstreams containing mixtures of aromatic and non-aromatic hydrocarbons using extractive distillation with an aromatic selective solvent in order to separate the aromatic hydrocarbons from the non-aromatic hydrocarbons. A rich solvent stream comprising the aromatic hydrocarbons and solvent is withdrawn from the extractive distillation column and passed to a steam stripping column to provide a regenerated lean solvent stream, a side-cut stream comprising the aromatic hydrocarbons and a stripper overhead stream comprising non-aromatic hydrocarbons which are passed as a reflux stream to the extractive distillation column. Various solvents are disclosed and an especially preferred solvent is sulfolane.

Abstract: In a solvent extraction/steam distillation process for the recovery of aromatic hydrocarbons wherein stripping water is obtained from the distillation column, the improvement comprising(a) dividing the stripping water into two streams;(b) passing one stream to a motive steam generator wherein the stripping water is vaporized and passed to a steam ejector;(c) passing the other stream to a heat exchanger wherein the stripping water is vaporized by lean solvent from the distillation column, the lean solvent is cooled, and the stripping water vapor passes to the steam ejector;(d) passing the stripping water vapor from steps (b) and (c) to the distillation column; and(e) passing the lean solvent from step (c) to the extractor.

Abstract: In a combination solvent extraction-steam distillation process for the recovery of aromatic hydrocarbons, the improvement comprising(a) introducing high pressure steam into a steam ejector;(b) passing the steam from step (a) to a first heat exchanger where it exchanges heat with cooler lean solvent coming from the bottom of the distillation column and is condensed;(c) returning the lean solvent from step (b) to the bottom of the distillation column;(d) passing part of the condensate from step (b) to a second heat exchanger where it exchanges heat with the warmer lean solvent coming from the bottom of the distillation column, cooling the lean solvent and vaporizing the condensate; and(e) passing the vapor from step (d) to the steam ejector in step (a).

Abstract: In a steam distillation process for the recovery of aromatic hydrocarbons wherein there is (i) a primary flash zone at the top of the distillation zone in which rich solvent is flashed and/or (ii) provision for the removal of side cut distillate vapors from about the middle of the distillation zone, the improvement comprising (a) heat exchanging flashed rich solvent vapors or side-cut distillate vapors with stripping water to provide stripping water vapors and stripping water at at least about the boiling point of water; (b) passing the stripping water vapors from step (a) to a steam ejector; (c) passing the stripping water from step (a) to a motive steam generator wherein the stripping water is vaporized under pressure; (d) passing the stripping water vapors from step (c) to the steam ejector referred to in step (b); and (e) passing the stripping water vapors, introduced into the steam ejector in accordance with steps (b) and (d), to the lower half of the distillation zone.

Abstract: An improvement to a continuous solvent extraction-steam distillation process for the recovery of aromatic hydrocarbons in the range of C.sub.6 -C.sub.16 from a feed stream containing such aromatics and aliphatic hydrocarbons in the range of C.sub.5 -C.sub.16 which resides in utilizing two heat exchangers wherein the heat of condensation of the overhead stripper vapor and vapor sidedraw products is recovered and utilized to vaporize the stripping water, thereby producing stripping steam which in turn is compressed up to the pressure present at the bottom of the stripper and resulting in the reduction of the heat load of the process.

Abstract: An improvement to a continuous solvent extraction-steam-distillation process for the recovery of aromatic hydrocarbons in the range of C.sub.6 -C.sub.16 from a feed stream containing such aromatics and aliphatic hydrocarbons in the range of C.sub.5 -C.sub.16 which resides in using two extractive distillation zones thermally linked to recover heat and solvent, thereby resulting in a heat savings.