Process for the direct conversion of a cut containing C4 and/or C5 for the production of propylene and co-production of a high-octane number desulfurised gasoline

摘要

Production of propylene and coproduction of a desulfurized gasoline of high octane index made of a charge having 4-5 carbon atom fraction (I) resulting from a steam-cracking unit and a fluid catalytic cracked gasoline (FCC) unit comprises selective hydrogenation of the FCC to give an effluent that is sent into a separation unit (21) to give a light fraction sent into an oligocracking unit (40), and a heavy fraction sent into a water-treatment unit (30) and separating the obtained fractions in a distillation columns (50) in to at least 5 fractions e.g. a propylene fraction. Production of propylene and coproduction of a desulfurized gasoline of high-octane index made of a charge containing 4-5 carbon atom fraction (I) resulting from a steam-cracking unit (A) and a fluid catalytic cracked gasoline (FCC) unit. The process comprises selective hydrogenation of FCC producing an effluent, which is sent into a separation unit (21) to give a light fraction sent into an oligocracking unit (40), and a heavy fraction containing more than 6 carbon atoms is sent into a water-treatment unit (30) and separating the obtained fractions in a distillation columns (50) into at least 5 fractions like: a fraction mainly made up of ethylene; a fraction of propylene; an intermediate fraction having a 4 carbon molecule in which a part is recycled at the entry of the oligocracking unit, and a non-recycled part is upgraded in liquefied petroleum gas; an intermediate fraction mainly made up of 5-6 carbon atom molecule in which a part is recycled at the entry of the oligocracking unit; and a non recycled part having gasoline directed towards the gasoline pool and a basic fraction of 9 carbon atom molecule sent in to the water-treatment unit in which an effluent from the water-treatment unit having the desulfurized gasoline.