GB1428228A - Process for recovering saturated hydrocarbons - Google Patents

Abstract

1428228 Extractive distillation SNAMPROGETTI SpA 23 Nov 1973 [29 Nov 1972] 54611/73 Heading C5E In a process for recovering saturated hydrocarbon from admixture with polar hydrocarbon the feed mixture in the vapour phase is subjected to extractive distillation at 50- 200‹ C. with a solvent mixture comprising an organic solvent and water and water is recovered from an overhead product of the extractive distillation and recycled to the extractive distillation zone at a point higher than the points at which the feed mixture and solvent mixture are fed into the column. As shown in Fig. 2 the vapourized feed 3, recycled solvent 25 and make-up solvent 6 are fed to the multi-plate bubble cap column 4. The overhead 7 is separated into saturated hydrocarbon 11 and water 10 which is recycled to the upper part of the column 4. The bottoms 42 is separated in a column 43 into a solvent stream 25 and an overhead stream from which water streams 46 and 47 are recycled to the column 43 and an aromatic hydrocarbon stream 49 is recovered. According to the second embodiment (Fig. 1, not shown) instead of using a column 43 as in Fig. 2 the bottoms from the column 4 is recycled to the column 4 via the head exchangers 2 and 19 and a vaporous side-stream (12) is removed from the column 4 at a point between the feed inlet 3 and the inlet from the reboiler 20. This side stream (12) is separated in a scrubbing column into a solvent and water containing stream, which is returned to the column 4, and an overhead which is separated into an aromatic hydrocarbon product and a water stream, which is recycled to the top of the scrubbing column. Suitable solvents are morpholine or a derivative thereof such as N-formyl morpholine; in the example a mixture of benzene and 95 wt. per cent n-hexane is separated.