Process for gas-phase polymerization of olefins

Abstract

A process for the polymerization of olefins in gas phase carried out in a reactor having two interconnected polymerization zones, a first zone (riser) and a second zone (downcomer), wherein growing polymer particles: a) flow through the riser under fast fluidization conditions established by feeding a mixture of gas and liquid; b) leave the riser and enter the downcomer, through which the growing polymer particles flow downward in a densified form; and c) leave the downcomer and are reintroduced into the riser, thereby establishing a circulation of polymer between the riser and the downcomer; the reactor is operated at a temperature between 0° C. and 5° C. above the dew point of the riser gas at the operating pressure, and in the riser, besides the growing polymer particles and gas flow, an amount of liquid is present.

Dependencies are inferred from the claim text.