Process for preparing polyolefins in suspension

US8148588B2 · kind B2 · utility

Assignee

• Basell Polyolefine GmbH · DE

Inventors

• Joachim Berthold · Prien am Chiemsee, DE
• Frank Alt · Frankfurt, DE
• Kaspar Evertz · Schifferstadt, DE
• Peter Kölle · Bad Dürkheim, DE

Key dates

• Filing date: Jan 25, 2005
• Grant date: Apr 3, 2012
• Expiry date: May 10, 2027

Classification

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

Abstract

The invention relates to a continuous process for preparing polyolefins having a bimodal or multimodal molar mass distribution in suspension in at least two reactors R1, R2.x, R3.y which are connected in series and in which different reaction conditions are set. In this process, the offgases A1, A2.x, A3.y, A4 and A5 leaving all the reactors connected in series are firstly collected, the collected offgases are then compressed in a compression stage 10, the compressed offgases are subsequently cooled and the cooled material is separated into a gaseous fraction and a liquid fraction. The separated fractions are then recirculated to the polymerization process at different points. The process of the invention allows the total conversion of the polymerization, based on monomer and comonomer used, to be increased to a surprising extent.