Patent ID: 7687588

Claim:
A process for gas-phase polymerization of α-olefins CH 2 ═CHR, wherein R is hydrogen or a hydrocarbon radical comprising 1-12 carbon atoms, carried out in a first interconnected polymerization zone, and a second interconnected polymerization zone, in which at least one of the α-olefins are fed in presence of a catalyst under reaction conditions, and from which a polymer product is discharged, wherein the process comprises: growing polymer particles by flowing the polymer particles through the first interconnected polymerization zone under fast fluidization conditions; the polymer particles leaving the first interconnected polymerization zone, and enter the second interconnected polymerization zone, wherein the polymer particles flow downward in a densified form, and leave the second interconnected polymerization zone, and are reintroduced into the first interconnected polymerization zone, the process further comprising: (a) a gas mixture present in the first interconnected polymerization zone being totally or partially prevented from entering the second interconnected polymerization zone, and (b) a gaseous composition inside a portion of the second interconnected polymerization zone is maintained substantially similar to a gaseous composition reacting in the first interconnected polymerization zone; wherein the process produces a (co)polymer composition, and at least one component of the (co)polymer composition is split by rising or lowering a feeding point of a corrective fluid in the second interconnected polymerization zone.