Bp Chemicals Limited

Andre Dumain

Charles Raufast

Jean-Claude Chinh

Laszlo Havas

Jean Engel

The present invention relates to a process and apparatus for the gas-phase polymerization of olefins in a fluidized-bed reactor maintained at a temperature T1. A gaseous reaction mixture comprising the olefins to be polymerized passes through the reactor and is recycled to the reactor by means of a recycling line comprising successively a first heat transfer means, a compressor and a second heat transfer means. The present invention consists in introducing a readily volatile liquid hydrocarbon into the inlet of the first heat transfer means or into the recycling line, upstream and in the vicinity of the first heat transfer means. The first heat transfer means cools the gaseous reaction mixture to a temperature T2, below T1, while volatilizing the readily volatile hydrocarbon and without condensing a constituent of the gaseous reaction mixture. The second heat transfer means cools the gaseous reaction mixture to a temperature T3, below T2, for maintaining the fluidized-bed at the desired temperature T1.

Apparatus for the gas-phase polymerization of olefins in a fluidized-bed

A process for the continuous polymerization of one or more alpha-olefins with a transition metal catalyst, in a reactor having a fluidized and/or mechanically stirred bed, in which a very small amount of an activity retarder, generally less than 0.1 ppm, is introduced continuously into the reactor at a flow rate which is varied with time so as to keep substantially constant either the polymerization rate or the content of transition metal in the polymer produced. Suitable activity retarders include polymerization inhibitors such as, for example, oxygen, alcohols, carbon monoxide and carbon dioxide and electron donor compounds such as amides and ethers.

Gas-phase alpha-olefin polymerization process in the presence of an

Process for the gas-phase polymerization of olefins in a fluidized-bed

Process for gas phase polymerization of olefins using a highly active catalyst in a fluidized bed reactor (1), comprising a recator body (2) partially occupied by the fluidized bed and surmounted by a disengagement chamber (3). The gas mixture withdrawn from the disengagement chamber (3) is fed to a dust separator (6) e.g. a clycone, to separate the fine particles entrained by the gas. The gas is cooled, compressed and recycled to the base of the reactor. The particles are withdrawn from the dust separator (6) by a mixing device (8) which mixes the particles with a carrier gas. The carrier gas and particles are recycled to the reactor where they are introduced into the reactor body (2) through an opening in the side wall thereof at a position above the fluidized bed, but below the disengagement chamber (3). The velocity of the particles introduced into the reactor is insufficient to cause them to be blown directly into the bed.

Process for gas phase polymerization of olefins in a fluidized bed

Device and process for introducing a powder with catalytic activity into a fluidized bed polymerization reactor (1), the said device comprising:

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Martigues, France

Andre Dumain