| 摘要 |
1,173,044. Solvent extraction. UNIVERSAL OIL PRODUCTS CO. 4 April, 1967 [5 April, 1966], No. 15379/67. Heading C5E. In a solvent extraction process utilizing solvent for the separation of a feed stock into a component which is soluble in the solvent and a component which is less soluble in the solvent than said soluble component, said feed is Contacted with a lean solvent in an extraction zone to form a rich solvent extract phase containing soluble component and a minor amount of less-soluble component, and a raffinate phase containing less-soluble component, the resulting extract phase is introduced into an extractive distillation zone to form an overhead fraction containing lesssoluble component and a bottoms fraction containing solvent and soluble component, the overhead fraction is recycled to the extraction zone and soluble component is recovered from the solvent, a portion of the extract phase being flash-vaporized and the resulting vapour portion combined with said overhead fraction before recycling the latter to the extraction zone. Additional solvent may be added to the extract phase before or after the flash-vaporization. As applied to the extraction of aromatics from hydrocarbon feedstocks the solvent may be sulpholane, sulpholene, dimethylsulpholane, polyethylene glycol or polypropylene glycol, and may contain up to 20% of water. The feedstock may be a reformate or a hydrotreated pyrolysis by-product. |
