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US 2004/0072971 A1Published application
Apparatus for gas-phase polymerization
AssigneeBasell Poliolefine Italia S.r.l.
InventorsGabriele Govoni, Massimo Covezzi
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AssigneeBasell Poliolefine Italia S.r.l.
InventorsGabriele Govoni, Massimo Covezzi
Estimating the term…
A process for the gas-phase catalytic polymerisation carried out in two interconnected polymerisation zones, to which one or more monomers are fed in the presence of a catalyst under polymerisation conditions and from which the produced polymer is discharged. The growing polymer particles flow through a first polymerisation zone under fast fluidisation conditions, leave said first zone and enter a second polymerisation zone through which they flow in a densified form under the action of gravity, leave said second zone and are reintroduced into the first polymerisation zone, thus establishing a circulation of polymer between the two polymerisation zones. The present invention is characterised in that a gas of composition different from that present in the first polymerisation zone is introduced into the second polymerisation zone and it is avoided that the gases present in the first polymerisation zone are introduced into the second polymerisation zone. The process is particularly suited for obtaining in-reactor made blends of olefin polymers having different compositions.
A process for the catalytic polymerisation in the gas-phase carried out in at least two interconnected polymerisation zones, the process comprising feeding one or more monomers to said polymerisation zones in the presence of catalyst under reaction conditions and collecting the polymer product from said polymerisation zones, in which process the growing polymer particles flow upward through one of said polymerisation zones (riser) under fast fluidisation or transport conditions, leave said riser and enter another polymerisation zone (downcomer) through which they flow downward under the action of gravity, leave said downcomer and are reintroduced into the riser, thus establishing a circulation of polymer between the riser and the downcomer, the process being further characterised in that:
An apparatus for the gas-phase catalytic polymerisation comprising a first vertical reactor (1), a second vertical reactor (2), the upper region of said reactor (1) being connected by a connecting part (3) to a solid gas separator (4), which is in turn connected to the upper region of said second reactor (2) the lower region of said second reactor (2) being connected to the lower region of said first reactor (1) by a connecting part (5) said solid/gas separator (4) being connected through a recycle line (6) to one ore more points of reintroduction into said connecting part (5) or into said reactor (1), said apparatus having a line (12) for catalyst feeding into said reactor (1), a polymer discharge system (11) from said reactor (2), a line (13) for feeding monomers, the said apparatus being further characterised in that it comprises a line (15) for feeding gas or liquid into said reactor (2).
Dependencies are inferred from the claim text.