| 摘要 |
FIELD: polymerization processes. ^ SUBSTANCE: invention relates to gas-phase polymerization processes wherein bimetallic catalytic systems are used and provides gas-phase polymerization process resulting in polyolefin composition, which process comprises passing gas stream containing gaseous hydrogen and one or several monomers, including ethylene monomers, through fluidized-bed reactor under reaction conditions and in presence of metallocene-containing catalyst to produce polyolefin composition, wherein, in an embodiment, volume density of fluidized bed constitutes 60% or more the volume density of settled mass (the same as if voidage would be equal to 40% or less) and wherein voidage is controlled by a series of factors including, in different embodiments: (a) reactor temperature maintained at a level of 100°C or below and (b) value of molar ratio between gaseous hydrogen and ethylene supplied to reactor and equaling 0.015 or less. ^ EFFECT: increased efficiency of catalyst in gas-phase processes and increased residence time of catalyst in fluidized bed of gas-phase reactor. |
