Patent ID: 8324327

Claim:
A process for polymerizing one or more olefins in a gas-phase reactor having a fluidized bed and a fluidizing medium having an operating gas density, the process comprising: determining a critical gas density for the fluidizing medium with the following equation, ( a × A ⁢ ⁢ P ⁢ ⁢ S × S ⁢ ⁢ B ⁢ ⁢ D S ⁢ ⁢ G ⁢ ⁢ V ) b wherein a is a constant having a value of 4.0, b is a constant having a value of 2.3, APS is an average particle size of the fluidized bed as measured in inches, SBD is a settled bulk density of polymer particles of the bed measured in lb/ft 3 , SGV is a gas velocity of the fluidizing medium as measured in ft/second; and adjusting the operating gas density of the fluidizing medium to be less than or equal to the critical gas density.