Patent ID: 7645843

Claim:
A process for producing olefin polymers, said process comprising the steps of: (i) forming in a catalyst feed vessel catalyst slurry comprising oil and a solid catalyst component; (ii) maintaining the catalyst slurry in the catalyst feed vessel in a homogeneous state; (iii) continuously withdrawing a portion of the catalyst slurry from the catalyst feed vessel and introducing the withdrawn portion of the catalyst slurry into a polymerization reactor; (iv) continuously introducing at least one olefin monomer into the polymerization reactor; (v) optionally, continuously introducing diluent and/or hydrogen into the polymerization reactor; (vi) operating the polymerization reactor in such conditions that the at least one olefin monomer is polymerized by the polymerization catalyst to form a reaction mixture containing the catalyst, unreacted monomer(s), formed polymer and optionally diluent and/or hydrogen; (vii) withdrawing a portion of the reaction mixture from the polymerization reactor, characterized in that the oil has a dynamic viscosity of from 30 to 990 mPa·s at the conditions within the catalyst feed vessel and the catalyst slurry is transferred by using a valveless piston pump from the catalyst feed vessel into the polymerization reactor.