Patent ID: 11891574
Assignee: SHELL USA, INC.
Field: Basic materials chemistry (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A process for steam cracking a hydrocarbon feed, the process comprising:
recovering aliphatic hydrocarbons from a liquid hydrocarbon feedstock stream to produce recovered aliphatic hydrocarbons, wherein the liquid hydrocarbon feedstock stream comprises a liquid product produced by pyrolysis of plastic waste; and
steam cracking a hydrocarbon feed which comprises the recovered aliphatic hydrocarbons,
wherein the liquid hydrocarbon feedstock stream comprises aliphatic hydrocarbons, polar components and optionally aromatic hydrocarbons,
wherein the aliphatic hydrocarbons comprise paraffinic and olefinic aliphatic hydrocarbons,
wherein the polar components comprise heteroatom containing organic compounds and optionally salts,
wherein the heteroatom containing organic compounds contain one or more heteroatoms and comprise oxygen containing organic compounds, nitrogen containing organic compounds and halogen containing organic compounds, and
wherein the amount of the polar components is at least 0.5 wt. % and the amount of the optional aromatic hydrocarbons is at most 20 wt. %,
wherein recovering aliphatic hydrocarbons from the liquid hydrocarbon feedstock stream comprises the steps of:
feeding the liquid hydrocarbon feedstock stream to a first column;
feeding a first solvent stream which comprises an organic solvent to the first column at a position which is higher than the position at which the liquid hydrocarbon feedstock stream is fed, wherein the organic solvent in the first solvent stream contains one or more heteroatoms;
contacting at least a portion of the liquid hydrocarbon feedstock stream with at least a portion of the first solvent stream; and
recovering at least a portion of the aliphatic hydrocarbons by liquid-liquid extraction of the polar components and optionally the aromatic hydrocarbons with the organic solvent,
resulting in a top stream from the first column comprising the recovered aliphatic hydrocarbons and a first portion of the organic solvent and a bottom stream from the first column comprising a second portion of the organic solvent, the polar components, and optionally the aromatic hydrocarbons;
feeding the top stream from the first column to a second column;
feeding a second solvent stream which comprises water to the second column at a position which is higher than the position at which the top stream from the first column is fed;
contacting at least a portion of the top stream from the first column with at least a portion of the second solvent stream; and
removing at least a portion of the organic solvent from the top stream from the first column by liquid-liquid extraction of the organic solvent with water,
resulting in a top stream from the second column comprising the recovered aliphatic hydrocarbons and a bottom stream from the second column comprising water and the organic solvent.