Process of making polyolefins

Abstract

The present invention relates to a process for the continuous production of a polyolefin, preferably polypropylene, in a horizontal stirred bed polymerization reactor by contacting one or more olefins, preferably propylene, with a catalyst system while stirring, said catalyst system comprising: * a procatalyst comprising i) titanium; ii) a magnesium-containing support, preferably a magnesium chloride-containing support, and iii) an internal electron donor; * optionally an external electron donor; and * a co-catalyst, being a alkyl aluminum catalyst having formula AlXR, wherein each X is independently a halide or a hydride and wherein n is 0, 1 or 2, preferably 0, and wherein R is an C1-C12 alkyl group, preferably ethyl, wherein the molar ratio of aluminum (Al) from the co-catalyst to titanium (Ti) from the procatalyst (Al/Ti) is at least 75. The present invention also relates to polyolefin prepared using said process and a shaped article comprising said polyolefin. The present invention moreover relates to the use of a titanium to aluminum ratio during the Ziegler-Natta polymerization of olefins in a horizontal stirred bed reactor to reduce the energy (power) consumption in view of a situation wherein the titanium to aluminum ratio is lower.