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AssigneeBasell Polyolefine GmbH
InventorsManfred Hecker, Paulus De Lange, Rainer Karer
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The instant invention relates to an activation of a polymerization catalyst precursor by heat treatment comprising a support material and a catalyst precursor deposited thereon in a fluidized bed activator and to the use of the activated polymerization catalyst in the manufacture of polyolefins. The activation involves heat treatment in the presence of oxygen. After that activation the oxygen in the activator is replaced by inert gas via flushing until the fluidization gas ermerging from the activator comprises oxygen in a maximum amount of up to 5 ppm. The catalyst prepared by that method is improved with respect to prevent reactor fouling during gas-phase polymerization or slurry polymerization either in stirred vessel or loop.
A method for the preparation of a Cr-containing polymerization catalyst comprising a fluidized-bed method for the activation of the chromium containing catalyst precursor by heat treatment, wherein the heat treatment is performed in an activator in the presence of oxygen at a temperature in the range of from 300 to 1000° C. over a time period of from 0.5 to 48 h and wherein after that activation the oxygen in the activator is replaced by inert gas via flushing until the fluidization gas emerging from the activator does comprise oxygen in a maximum amount of up to 5 ppm, preferably up to 3 ppm, more preferred up to 2 ppm and mostly preferred up to 1 ppm.
Dependencies are inferred from the claim text.