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AssigneeSasol Technology (Pty) Ltd
InventorsJohan Pieter De Wet, Jacob Johannes Scholtz
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This invention relates to a method for separating olefins and paraffins from oxygenates in a liquid hydrocarbon stream containing a high proportion of olefins, paraffins and oxygenates (mainly alcohols). Typically, the hydrocarbon stream is obtained from a Fischer-Tropsch process. The organic counter-solvent has a boiling point which is less than the boiling point of the most volatile alcohol in the hydrocarbon stream. A raffinate from the liquid-liquid extractor is passed to a distillation column. A bottoms product from the distillation column comprises olefins and paraffins, and the overhead product comprising solvents is recycled. An extract from the liquid-liquid extractor is sent to a stripping column, where a bottoms product containing pure alcohol is obtained. The overhead product containing counter-solvent is recycled.
A method for separating olefins and paraffins from oxygenates in a liquid hydrocarbon stream including hydrocarbons and oxygenates, the method including contacting the hydrocarbon stream under conditions of liquid-liquid extraction with a polar solvent and a non-polar organic counter-solvent, wherein the organic counter-solvent comprises olefins and/or paraffins.
The method according to claim 2 wherein the organic counter-solvent is selected to have a boiling point which is less than the boiling point of the most volatile alcohol in the hydrocarbon stream.
The method according to any one of the preceding claims wherein a raffinate from the liquid-liquid extractor is introduced into a distillation column and a mixture of paraffins and olefins is recovered as a bottoms product from the distillation column.
The method of any one of the preceding claims wherein the overhead product from the distillation column is recycled to the lower counter-solvent inlet of the extraction column.
The method according to any one of the preceding claims wherein an extract from the liquid-liquid extractor is sent to a stripping column, and an overhead product from the stripping column is recycled to the upper solvent inlet of the extraction column.
The method according to any one of the preceding claims wherein the bottoms product from the stripping column is an oxygenate stream containing low concentrations of non-polar material.
A method for separating olefins and paraffins from oxygenates in a liquid hydrocarbon stream comprising C4 to over C20 hydrocarbons and oxygenates, the method including the steps of:
Dependencies are inferred from the claim text.