Slurry phase polymerisation process

Sludge phase polymerization process. A process comprising polymerizing an olefin monomer optionally together with an olefin copolymer in the presence of a polymerization catalyst in a diluent in a circulatory reactor which comprises at least 2 horizontal sections and at least 2 vertical sections to produce a Slurry comprising solid particulate olefin polymer and the diluent whereby the number of froud in at least 20% of the length of the vertical sections of the circulatory reactor is less than 85% of the number of froud in at least 20% of the horizontal sections of the circuit Is revealed.