Patent ID: 8796400

Claim:
A method for controlling the injection of catalyst slurry in a polymerization reactor, wherein polyethylene is prepared, said catalyst slurry comprising solid catalyst in a hydrocarbon diluent, the method comprising: providing solid catalyst and a hydrocarbon diluent in one or more storage vessels such that a catalyst slurry is obtained in said one or more storage vessels; transferring said catalyst slurry from said one or more storage vessels to a mixing vessel, wherein said catalyst slurry is diluted for obtaining a suitable concentration for use in a polymerization reaction; pumping said diluted catalyst slurry at a controlled flow rate from said mixing vessel to said polymerization reactor through one or more conduits, by means of a pumping means, provided in each of said conduits, and the dilution being adapted to the pumping means; and controlling the flow rate of said catalyst slurry from the mixing vessel to the polymerization reactor by determining the concentration of a reactant in said polymerization reactor.