| CPC C10G 55/04 (2013.01) [C07C 7/10 (2013.01)] | 10 Claims |
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1. A process for the recovery of aliphatic hydrocarbons from a liquid hydrocarbon feedstock stream comprising aliphatic hydrocarbons, heteroatom containing organic compounds and optionally aromatic hydrocarbons, said process comprising the steps of:
a) mixing at least part of the liquid hydrocarbon feedstock stream with a stream having a pH above 7 and comprising a washing solvent a) which contains one or more heteroatoms and separating the resulting mixture into a first stream comprising washing solvent a) and heteroatom containing compounds and a second stream comprising aliphatic hydrocarbons, heteroatom containing organic compounds and optionally aromatic hydrocarbons,
said step a) further comprising:
a1) before mixing with the stream having a pH above 7: mixing at least part of the liquid hydrocarbon feedstock stream with a stream having a pH below 7 and comprising a washing solvent a) which contains one or more heteroatoms and separating the resulting mixture into a first stream comprising washing solvent a) and heteroatom containing compounds and a second stream comprising aliphatic hydrocarbons, heteroatom containing organic compounds and optionally aromatic hydrocarbons, and mixing at least part of said second stream with the stream having a pH above 7, and/or
a2) after mixing with the stream having a pH above 7: mixing at least part of the second stream, resulting from the mixing with the stream having a pH above 7 and the separation into first and second streams, with a stream having a pH below 7 and comprising a washing solvent a) which contains one or more heteroatoms and separating the resulting mixture into a first stream comprising washing solvent a) and heteroatom containing compounds and a second stream comprising aliphatic hydrocarbons, heteroatom containing organic compounds and optionally aromatic hydrocarbons, and feeding at least part of said second stream to step b); and
b) contacting at least part of the second stream resulting from step a) with an extraction solvent b) which contains one or more heteroatoms and subjecting that stream to liquid-liquid extraction with extraction solvent b), resulting in a first stream comprising aliphatic hydrocarbons and optionally heteroatom containing organic compounds and a second stream comprising extraction solvent b), heteroatom containing organic compounds and optionally aromatic hydrocarbons.
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