US Patent 7875685 Gas phase polymerization and distributor plate passivation treatment

Apparatus and methods for gas phase polymerization are provided. The method can include polymerizing one or more olefins at gas phase conditions in a reactor comprising one or more process exposed surfaces in the presence of a catalyst system; and treating at least a portion of the one or more process exposed surfaces prior to injecting the catalyst system to reduce the number of surface hydroxyls or access of the catalyst system to the surface hydroxyls on the process exposed surfaces.