GB1346778A - Selective hydrogenation of gasolines - Google Patents

Abstract

1346778 Hydrogenating unsaturated gasolines BRITISH PETROLEUM CO Ltd 5 Jan 1972 [11 Feb 1971] 4444/71 Heading C5E An unsaturated gasoline 4, boiling in the range 15-100‹C. and containing diolefins, including cyclopentadiene, mono-olefins and aromatics, is catalytically hydrogenated in the liquid phase at 50-250‹ C. and 200-3000 psig. to reduce the diolefin content; the pressure on the hydrogenated liquid is reduced at 5 at 50- 250‹ C. to vaporize up to 60 wt. per cent of the liquid based upon the hydrogenated product boiling above 15‹ C.) to form a product 11 without decomposition of dicyclopentadiene (formed from the cyclopentadiene), the remaining liquid is separated at 6 to produce a vaporized stream 11 which is recycled to the hydrogenation zone and a residual liquid fraction 18 (amounting to up to 5 wt. per cent of the effluent from the hydrogenation zone) which is discarded. The hydrogenation can be carried out in one or more stages with interstage cooling by interstage injection of hydrogen, fresh feed or recycle feed or by indirect heat exchange. The hydrogenation catalyst can comprise 1-50 wt. per cent of an iron group metal, e.g. Ni, or 0À1-10 wt. per cent of a platinum group metal, e.g. Pd, on a support such as chalk, alumina, silica, keiselguhr or sepiolite. The catalyst can be sulphided by thiophenic sulphur in the feed or presulphided with thiophenic or tetrahydrothiophenic sulphur. The separation stages can be flash vaporization, distillation or fractionation. The unsaturated gasoline feed is produced by catalytic or thermol cracking, e.g. in the presence of diluent steam or heated sand, and contains 10-40 wt. per cent cyclopentadiene.