Polyolefin manufacturing system including a membrane fractionation system for diluent recovery
AssigneeChevron Phillips Chemical Company LP
InventorsAndrew J. Mills, Andrea L. Hoener, Ralph W. Romig
Life of this patent
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Abstract
A fractionation system for a polymerization reactor includes a membrane separation system designed to separate light components, such as unreacted monomer and inerts, from diluent. The membrane separation system may employ one or more membrane modules designed to separate hydrocarbons based on size, solubility, or combinations thereof. The fractionation system also may include a heavies fractionation column designed to separate heavy components, such as unreacted comonomer and oligomers, from the diluent.
Claims20
A method for recovering diluent from polymerization reactor effluent, the method comprising:
- separating effluent from a polymerization reactor into extracted polyolefin solids, a first stream including primarily diluent and heavy components, and a second stream including primarily the diluent and light components;
- fractionating the first stream in a heavies fractionation column to produce a first discharge stream including primarily the heavy components and a second discharge stream including primarily the diluent;
- and
- separating the second stream in a membrane separation system to produce a diluent enriched stream including primarily the diluent and a lights enriched stream including primarily the light components, wherein the membrane separation system is an integral top portion of the heavies fractionation column.
A method for producing polyolefin solids, comprising:
- polymerizing an olefin monomer in a polymerization reactor to produce a slurry having polyolefin solids, isobutane, heavy components, and light components;
- discharging the slurry from the polymerization reactor as an effluent;
- producing a first stream, a second stream, and polyolefin solids from the effluent in an effluent treatment system;
- fractionating the first stream in a heavies fractionation column to produce a first discharge stream including primarily the heavy components and a second discharge stream including primarily the light components and the isobutane;
- separating the second stream in a membrane separation system to produce an isobutane enriched stream including primarily the isobutane and a lights enriched stream including primarily the light components;
- recycling at least a portion of the isobutane enriched stream directly to a separation unit of the effluent treatment system;
- and
- processing the polyolefin solids to produce polyolefin fluff.
A method for producing polyolefin solids, comprising:
- producing a first stream, a second stream, and polyolefin solids from effluent discharged from a polymerization reactor in an effluent treatment system;
- fractionating the first stream in a heavies fractionation column to produce a first discharge stream including primarily heavy components and a second discharge stream including primarily light components and isobutane;
- separating the second stream in a membrane separation system to produce an isobutane enriched stream including primarily the isobutane and a lights enriched stream including primarily the light components;
- recycling at least a portion of the isobutane enriched stream directly to a separation unit of the effluent treatment system;
- and
- processing the polyolefin solids to produce polyolefin fluff.
Dependencies are inferred from the claim text.