Isoprene extraction with preserved C5 feedstock
AssigneeSabic Global Technologies B.V.
InventorMohamed Sabri Abdelghani
Life of this patent
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Abstract
A process for extracting isoprene from a pyrolysis gas mixture or a C5 fraction wherein isoprene is purified by plural extractive distillations in the presence of a polar solvent and cyclopentadiene is effectively removed and recycled as a feedstock without being converted into its dimer, dicyclopentadiene. The isoprene recovered from the process described is more than 99.5% pure.
Claims19
A process of extracting isoprene from a mixture comprising C5 hydrocarbons, comprising:
- feeding the mixture comprising C5 hydrocarbons into a first extractive distillation column and extractively distilling the mixture by contact with a first polar solvent to form a first overhead product comprising isoprene and a first slip stream comprising cyclopentadiene and substantially no dicyclopentadiene;
- feeding the first overhead product to a second extractive distillation column and extractively distilling the first overhead product by contact with a second polar solvent to form a second overhead product comprising unextracted C5 hydrocarbons and a second slip stream comprising isoprene and other hydrocarbons;
- washing the second slip stream with water in a solvent wash column;
- cooling the second overhead product in a cooler;
- and
- distilling the second slip stream in a distillation column to form a third overhead product comprising high-purity isoprene, and a bottom product.
A process of extracting isoprene from a mixture comprising C5 hydrocarbons, comprising:
- feeding the mixture comprising C5 hydrocarbons into a first extractive distillation column and extractively distilling the mixture by contact with a first polar solvent to form a first overhead product comprising isoprene and a first slip stream comprising cyclopentadiene and substantially no dicyclopentadiene;
- feeding the first overhead product to a second extractive distillation column and extractively distilling the first overhead product by contact with a second polar solvent to form a second overhead product comprising unextracted C5 hydrocarbons and a second slip stream comprising isoprene and other hydrocarbons;
- removing solvent impurity in the second slip stream in a solvent wash column;
- cooling the second slip stream;
- and
- distilling the second slip stream in a distillation column to form a third overhead product comprising high-purity isoprene, and a bottom product.
A process of extracting isoprene from a Pygas mixture comprising C5 to C10 hydrocarbons, comprising:
- distilling the Pygas mixture in a depentanizer distillation column to form a first overhead product comprising C5 hydrocarbons and a first bottom product comprising C6 to C10 hydrocarbons;
- feeding the first overhead product into a first extractive distillation column and extractively distilling the first overhead product by contact with a first polar solvent to form a second overhead product comprising isoprene, and a first slip stream comprising cyclopentadiene and substantially no dicyclopentadiene;
- feeding the second overhead product to a second extractive distillation column and extractively distilling the second overhead product by contacting with a second polar solvent to form a third overhead product comprising unextracted C5 hydrocarbons, and a second slip stream comprising isoprene and other hydrocarbons;
- distilling the second slip stream;
- washing the second slip stream in a solvent wash column;
- cooling the second slip stream;
- and
- feeding the second slip stream to a distillation column to form a fourth overhead product comprising high-purity isoprene, and a bottom product.
Dependencies are inferred from the claim text.