GB1264373A - - Google Patents

Abstract

1,264,373. Hydrofining; recovering aromatic hydrocarbons. BETHLEHEM STEEL CORP. 5 June, 1969 [6 June, 1968], No. 28568/69. Heading C5E. A crude aromatic oil stream 11 boiling at up to 200‹ C., e.g. resulting from the carbonization of coal, and containing polymerizable compounds, non-aromatic compounds, oxygen compounds and sulphur compounds is separated into a stream 13 boiling below 120‹ C. and a stream 31 boiling above 120‹ C. Components boiling below 80‹ C. are removed from the stream 13 at 14 and the stream is then vaporized by mixing with the stream 17 of hot recycle hydrogen. The vapour stream 19 produced is reacted in the reactors 21, 22 and 23 at 550- 675‹ C. and 28-105 kg./cm.<SP>2</SP> gauge using a chromia-alumina catalyst to hydrocrack olefins, paraffins and naphthalene to C 1 to C 4 hydrocarbons, to hydrogenate sulphur compounds and to hydrodealkylate toluene. The stream 31 is distilled at 32 to remove a stream 37 from which naphthalene can be recovered and the 120- 200‹ C. fraction 33 is vaporized by mixing with the hot recycle hydrogen stream 38. The vaporized stream is reacted in the pretreater 34 at 250-375‹ C. and 21-105 kg. cm.<SP>2</SP> gauge using a catalyst of sulphided nickel molybdate or copper molybdate on alumina to convert polymerizable components to non-polymerizable components and oxygen-containing compounds to hydrocarbons and water. The effluent from the pretreater 34 is condensed and the stream 45, after separation at 43 of the gas 47 and the water 44 is passed to the second stage 22 of the hydro-upgrading zone. The gaseous effluent 24 from the reactor 23 is condensed and separated at 27 into a gaseous stream 28 and a liquid stream 29 which is separated into a H 2 S- and C 1 -C 4 hydrocarbon-containing stream 62, and after treatment with clay at 64 is separated into a pure benzene stream 70, a toluene stream 71 which is recycled to the hydro-upgrading zone 21, 22, 23 in admixture with the low boiling stream 16, a C 8 stream 72 comprising xylenes and ethyl benzene, a C 9 stream 73 which is recycled to the zone 23 with the pretreated stream 45 and a C 10 - and biphenyl-containing stream 74 which is recycled to the second hydro-upgrading zone 22.