Slurry phase polymerisation process

US8183332B2 · kind B2 · utility

Assignee

• INEOS MANUFACTURING BELGIUM NV · BE

Inventors

• Benoit Koch · Hannut, BE
• Daniel Marissal · Braine-le-Comte, BE
• Marc Parisel · Vilvoorde, BE
• Brent R. Walworth · Sint-Niklaas, BE

Key dates

• Filing date: Aug 29, 2008
• Grant date: May 22, 2012
• Expiry date: Feb 6, 2029

Classification

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

Abstract

Process for producing a multimodal polyethylene in at least two reactors connected in series, in which 20-80 wt % of a high molecular weight (HMW) polymer is made in suspension in a first reactor and 20-80 wt % of a low molecular weight (LMW) polymer is made in suspension in a second reactor. The ratio of the average activity in the LMW reactor to the average activity in the HMW reactor is from 0.25 and 1.5, where average activity in each reactor is defined as the rate of polyethylene produced in the reactor (kgPE/hr)/[ethylene concentration in the reactor (mol %)×residence time in the reactor (hours)×feed rate of catalyst into the reactor (g/hr)], residence time being defined as the mass of the polymer in the reactor (kg)/the output rate of polymer from the reactor (kg/hr). The volume of the second reactor is at least 10% greater than the volume of the first reactor, and the ratio of length to diameter of the first reactor, L/D(1), is greater than that of the second reactor, L/D(2).