Olefin polymerization process in a gas-phase reactor having three or more polymerization zones

US10968293B2 · kind B2 · utility

Assignee

• Basell Polyolefine GmbH · DE

Inventors

• Gerhardus Meier · Frankfurt, DE
• Ulf Schueller · Weiterstadt, DE

Key dates

• Filing date: Nov 9, 2017
• Grant date: Apr 6, 2021
• Expiry date: Mar 2, 2038

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F110/02
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Process for preparing an olefin polymer including the step of polymerizing an olefin in the presence of a polymerization catalyst and hydrogen as molecular weight regulator in a gas-phase polymerization reactor to yield growing polymer particles, the reactor including three or more polymerization zones and at least two thereof are sub-zones of a polymerization unit wherein the growing polymer particles flow downward in a densified form and at least one polymerization zone has a ratio of hydrogen to the sum of olefins which is a factor of at least 1.5 lower than the ratio of hydrogen to the sum of olefins in the polymerization zone having the highest ratio of hydrogen to the sum of olefins and a factor of at least 1.5 higher than the ratio of hydrogen to the sum of olefins in the polymerization zone having the lowest ratio of hydrogen to the sum of olefins.