Patent ID: 7504464

Claim:
A gas phase olefin polymerization process comprising: (1) preparing a solution of a catalyst precursor comprising a mixture of magnesium and titanium compounds, an electron donor and a solvent; (2) adding a filler to the solution from step (1) to form a slurry; (3) spray drying the slurry from step (2) at a temperature of 100 to 140° C. to form a spray dried precursor; (4) slurrying the spray dried precursor from step (3) in mineral oil, (5) partially pre-activating the catalyst precursor by contacting the slurry of step (4) with one or more Lewis Acids employing one or more in-line static mixers, wherein the molar ratio of the Lewis Acid tote electron donor in the catalyst precursor is about 0.1:1 to about 0.3:1; and (6) transferring the partially pre-activated catalyst precursor from step (5) under plug-flow conditions into a gas phase, olefin polymerization reactor, and adding an additional amount of the activator to the reactor in an amount sufficient to produce a homogeneous activated catalyst mixture, wherein the molar ratio of the Lewis Acid to the electron donor after the additional amount of activator is added is about 2:1 to about 50:1, and wherein the catalyst is partially pre-activated in step (5) for a short residence time to minimize deactivation of the catalyst of about 1 minute to about 6 hours prior to the transferring step (6).