| 摘要 |
1,232,151. Separating aromatic and paraffin hydrocarbons by solvent extraction. MARATHON OIL CO. 25 July, 1969 [19 Aug., 1968], No. 37560/69. Heading C5E. A simultaneous dual extraction of two feeds, No. 1 feed comprising " light " aromatic and " light " paraffin hydrocarbons, and No. 2 feed comprising " heavy " aromatics and "heavy " paraffins, is effected by: (a) feeding the light No. 1 feed (i) to a first extractor 4, and (b) also feeding thereto a selective solvent 12 for aromatics, already containing heavy aromatics, (c) withdrawing therefrom an extract 10 containing solvent and light aromatics, (d) also withdrawing therefrom a raffinate 14 comprising light paraffins, heavy aromatics and a little solvent, (e) feeding the extract 10 to a second extractor 8 and (f) also feeding thereto the heavy No. 2 feed, (g) withdrawing therefrom an extract 12 containing solvent and heavy aromatics, (h) also withdrawing therefrom a raffinate 16 comprising heavy paraffins, light aromatics and a little solvent, (i) feeding the extract 12 from (g) to the first extractor 4, (j) removing entrained solvent from the raffinate 14, and (k) similarly treating the raffinate 16, (1) distilling at 48 the raffinate 44 to separate light paraffins from heavy aromatics, and (m) distilling at 50 the raffinate 46 to separate heavy paraffins from light aromatics, thus yielding separate streams of light aromatic, heavy aromatic, light paraffinic, and heavy paraffinic product. " Light " and " heavy " are used herein for boiling ranges of 100-400‹ F. and 400-700‹ F. respectively. The solvent contains 1-30% by vol. water and preferably 0-99% dimethylformamide and 0-99% tetramethylene sulphone, and is removed from the raffinates by water-washing at 18 and 20. Extraction is effected at 40-150‹ F. in the liquid phase. The light and heavy feeds may comprise reformed naphtha (" reformate ") and light catalytic cycle oils respectively. The ratio of the extract (c) to the light feed is 0À5-8 vols./vol., and of the heavy to the light feed 0À15-6 vols./vol. |
