Patent ID: 8497330

Claim:
A method for gas phase olefin polymerization, comprising: combining a spray dried catalyst system with a diluent to produce a catalyst slurry; introducing ethylene, a continuity additive, and the catalyst slurry to a gas phase fluidized bed reactor, wherein the continuity additive is present in an amount ranging from about 1 ppmw to about 50 ppmw, based on a rate of polyethylene production; operating the reactor at conditions sufficient to produce a polyethylene, wherein the spray dried catalyst system has a catalyst productivity of at least 12,000 grams polyethylene per gram of the catalyst system, wherein the spray dried catalyst system comprises a metallocene compound which has the formula: Cp A Cp B Mx n , wherein M is hafnium; Cp A and Cp B are each bound to M and are independently selected from the group consisting of cyclopentadienyl ligands, substituted cyclopentadienyl ligands, ligands isolobal to cyclopentadienyl and substituted ligands isolobal to cyclopentadienyl; X is a leaving group selected from the group consisting of chloride ions, bromide ions, C 1 to C 10 alkyls, and C 2 to C 12 alkenyls, carboxylates, acetylacetonates, and alkoxides; and n is an integer from 1 to 3.