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US 5,849,982 AGranted
Recovery of styrene from pyrolysis gasoline by extractive distillation
AssigneeHFM International, Inc.
InventorsFu-Ming Lee, Joseph C. Gentry, Randi Wright Wytcherley
Life of this patent
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Abstract
An extractive distillation process for separating at least one substituted unsaturated aromatic from a pyrolysis gasoline mixture, containing said aromatic and at least one close-boiling aromatic or non-aromatic hydrocarbon, employing a two part extractive solvent, the first part selected from propylene carbonate, sulfolane (tetramethylene sulfone), methyl carbitol, 1-methyl-2-pyrrolidinone, 2-pyrrolidinone and mixtures thereof, and the second portion consisting of water.
Claims16
A process for producing styrene from a feedstock comprising styrene and at least one close-boiling aromatic or non-aromatic hydrocarbon comprising:
- feeding said feedstock into a single distillation column;
- feeding two-part extractive solvent into said distillation column, said solvent consisting essentially of a first part selected from the group consisting of propylene carbonate, sulfolane (tetramethylene sulfone), methyl carbitol, 1-methyl-2-pyrrolidinone, 2-pyrrolidinone, and mixtures thereof, but not including water, and a second part consisting of water, said two parts of said two-part extractive solvent being fed to said distillation column separately and independently at different locations along said single distillation column;
- distilling said feedstock in said distillation column in the presence of said extractive solvent to produce:
- (a) a solvent fraction relatively rich in styrene compared to the solvent fed to said distillation column;
- and
- (b) an overhead fraction comprising said at least one close-boiling aromatic or non-aromatic hydrocarbon and being relatively lean in styrene compared to said feedstock;
- withdrawing said solvent fraction from said distillation column;
- and
- withdrawing said overhead fraction from said distillation column.
6 more elements
A process for producing styrene from a feedstock comprising styrene and at least one close-boiling aromatic or non-aromatic hydrocarbon comprising:
- feeding said feedstock into a single distillation column;
- feeding two-part extractive solvent into said distillation column, said solvent consisting essentially of a first part selected from the group consisting of propylene carbonate, sulfolane (tetramethylene sulfone), methyl carbitol, 1-methyl-2-pyrrolidinone, 2-pyrrolidinone, and mixtures thereof, but not including water, and a second part consisting of water, said two parts of said two-part extractive solvent being fed to said distillation column separately and independently at different locations along said single distillation column;
- distilling said feedstock in said distillation column in the presence of said extractive solvent to produce:
- (a) a solvent fraction relatively rich in styrene compared to the solvent fed to said distillation column;
- and
- (b) an overhead fraction comprising said at least one close-boiling aromatic or non-aromatic hydrocarbon and being relatively lean in styrene compared to said feedstock;
- withdrawing said solvent fraction from said distillation column;
- withdrawing said overhead fraction from said distillation column;
- and
- in which at least a portion of said overhead fraction is hydrogenated to produce a mixture containing toluene and xylene.
7 more elements
A process for producing styrene from a feedstock comprising styrene and at least one close-boiling aromatic or non-aromatic hydrocarbon comprising:
- feeding said feedstock into a single distillation column;
- feeding two-part extractive solvent into said distillation column, said solvent consisting essentially of a first part selected from the group consisting of propylene carbonate, sulfolane (tetramethylene sulfone), methyl carbitol, 1-methyl-2-pyrrolidinone, 2-pyrrolidinone, and mixtures thereof, but not including water, and a second part consisting of water, said two parts of said two-part extractive solvent being fed to said distillation column separately and independently at different locations along said single distillation column;
- distilling said feedstock in said distillation column in the presence of said extractive solvent to produce:
- (a) a solvent fraction relatively rich in styrene compared to the solvent fed to said distillation column;
- and
- (b) an overhead fraction comprising said at least one close-boiling aromatic or non-aromatic hydrocarbon and being relatively lean in styrene compared to said feedstock;
- withdrawing said solvent fraction from said distillation column;
- withdrawing said overhead fraction from said distillation column;
- and
- in which said solvent fraction is fed to a stripping zone in which styrene, a portion of said aromatic or non-aromatic hydrocarbon and water are separated into a stripper overhead stream from solvent which constitutes a lean solvent bottom stream, and which is recycled to said distillation column as the first part of said two-part extractive solvent;
- and
- in which said stripper overhead stream is fed to a styrene purification zone in which hydrocarbon components, including cyclopentadiene, and water are separated into a styrene purifier overhead stream, purified styrene is separated into a styrene purifier side stream, and a styrene purifier bottom stream containing some of the first part of said extractive distillation solvent is formed in said styrene purifier zone.
9 more elements
Dependencies are inferred from the claim text.