Abstract: A gas-phase polymerization system and a solids recovery system for a fluidized bed reactor. The fluidized bed reactor can include a fluidizing gas outlet from which a discharged mixture of fluidizing gas and polymer fines is released, and a cyclone separator can separate the polymer fines from the fluidizing gas for reentry into the fluidized bed reactor. It has been found that by situating the reactor entry nozzle of the fines return line which is closest to the gas-phase reaction zone significantly higher in the reaction zone than in a conventional fines return line, and by directionally orientating the incoming stream of polymer fines and carrier gas into the fluidized bed in the reaction zone, a significant increase in the residence time of the particle in the reaction and larger particles which meet a product size distribution specifications are achieved.

Abstract: A gas-phase polymerization system and a solids recovery system for a fluidized bed reactor. The fluidized bed reactor can include a fluidizing gas outlet from which a discharged mixture of fluidizing gas and polymer fines is released, and a cyclone separator can separate the polymer fines from the fluidizing gas for reentry into the fluidized bed reactor. It has been found that by situating the reactor entry nozzle of the fines return line which is closest to the gas-phase reaction zone significantly higher in the reaction zone than in a conventional fines return line, and by directionally orientating the incoming stream of polymer fines and carrier gas into the fluidized bed in the reaction zone, a significant increase in the residence time of the particle in the reaction and larger particles which meet a product size distribution specifications are achieved.