Polythylene High Density (HOPE ) -Slurry Process

Abstract

Catalysts consisting of a mixture of alkylaluminium chlorides and alkyltitanium chlorides, plus ethylene, diluent (hexane or cyclohexane), and comonomer (when required), hydrogen (for molecular weight control) are charged to the reactor. Ethylene conversion is 40-50 percent at 60-80oC and 3-5 bar at a residence time of one-two hours. The polymer slurry is flashed, and deactivated, by treating with alcohol and then with water. After catalyst removal, the polymer slurry is centrifuged, and washed. The effluent from the centrifuge is fractionated to recover the hexane or cyclohexane. The polymer cake is dried and pelletised.