Olefin polymerization process

US10202472B1 · kind B1 · utility

Assignee

• Basell Polyolefine GmbH · DE

Inventors

• Gerhardus Meier · Frankfurt, DE
• Ulf Schueller · Weiterstadt, DE
• Claudio Fibla · Königstein, DE
• Shahram Mihan · Bad Soden, DE

Key dates

• Filing date: Feb 23, 2017
• Grant date: Feb 12, 2019
• Expiry date: Feb 23, 2037

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F210/16
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A process for the preparation of an ethylene polymer including the step of polymerizing ethylene or copolymerizing ethylene and one or more other olefins in the presence of a Phillips-type chromium catalyst in a gas-phase polymerization reactor containing a reactor bed of particulate polymer, wherein the gas-phase polymerization reactor is equipped with a cycle gas line, wherein the reactor gas returned to the polymerization reactor through the cycle gas line has been condensed in part and the amount of liquid in the returned reactor gas is from 0.5 wt. % to 10 wt. % based upon the total weight of the reactor gas/liquid composition, the polymerization is carried out at from 108° C. to 125° C., and an aluminum alkyl is fed into the polymerization reactor in an amount in the range of from 0.0025 mole to 0.1 mole per ton of dosed ethylene.