| 摘要 |
In a process for separating a hydrocarbon mixture by means of liquid-liquid extraction by a selective solvent boiling higher than the mixture, a raffinate and an extract phase being obtained, the extract phase being separated into solvent and an extract, and solvent being recovered from the raffinate and/or the extract by washing at least one of these by means of an aqueous washing medium, the used washing medium is then treated for recovery of solvent therefrom by contacting it with a hydrocarbon-containing mixture, e.g. the incoming feed hydrocarbon mixture. Additional solvent may be recovered from the contacted used washing medium by distillation, and the finally treated aqueous washing medium may be recycled. Suitable solvents are of the sulpholane or glycol type, examples being given, and the process is particularly suitable for recovering aromatics from kerosene or catalytic reformates. In the illustrated embodiment, feed hydrocarbon 1 is used to wash a water/sulpholane mixture 7 <PICT:1082188/C4-C5/1> in column 3, the solvent-freed water leaving at 5, and the hydrocarbon/sulpholane mixture 8 then being countercurrently contacted in column 9 with sulpholane 11. The extract 15 is then stripped in column 17 to give a non-aromatic extract which is returned to column 9, and an aromatic extract 21 which is passed to column 23 where sulpholane is separated and recycled to column 9. The raffinate 13 from column 9 and the aromatics 25 from column 23 are separately washed for removal of solvent by water 28 and 33 in columns 27 and 32, respectively, the used water now containing sulpholane being combined as stream 7 which is passed to unit 3 for contact with incoming feed. The washed raffinate and aromatics are recovered as 29 and 35 respectively. |
