FIELD: chemistry.
SUBSTANCE: invention relates to an improved method for gas-phase polymerisation of olefins in two or more flow modes. Described is a method of producing polypropylene or propylene copolymer, which involves polymerisation of propylene in a reactor. The reactor has two or more different flow modes. One of the flow modes has volume content of the solid phase in a multi-phase stream greater than 15%. A system based on a mixed external electron donor is fed into the reactor, where the system contains at least one selectivity control agent and at least one activity limiting agent. A catalyst system further includes an aluminium-containing co-catalyst, where molar ratio of aluminium to the mixed external electron donor is in the range of 0.5-4.0:1.
EFFECT: preventing agglomeration of particles in the reactor and formation of polymer agglomerates.
17 cl, 1 tbl, 4 ex
