Abstract: Process for the polymerisation or copolymerisation in the gas phase of olefin(s) by bringing the said olefins(s) into contact, under polymerisation or copolymerisation conditions in a reactor in which the polymer or the copolymer is maintained in a fluidized bed and/or agitated with mechanical stirring, with a catalyst system, which process comprises a pre start-up operation characterized in that, prior to the introduction of the catalytic system in the reactor, the reactor is subjected in a cleaning treatment comprising the steps of introducing into the reactor an alkane having from 4 to 8 carbon atoms, circulating said alkane across the reactor under pressure and elevated temperature, depressurizing and purging the reactor.

Abstract: The present invention relates to a process for the gas-phase (co-)polymerization of olefins in a fluidised bed reactor using a late transition metal catalyst characterised in that the polymerization is performed in the presence of a process aid additive.

Abstract: The present invention relates to a process for the gas-phase (co-) polymerisation of olefins in a fluidised bed reactor using a late transition metal catalyst characterised in that the polymerisation is performed in the presence of a process aid additive.

Abstract: A process for the continuous gas-phase (co-)polymerisation of olefins in a fluidised bed reactor using a Ziegler-Nata type catalyst wherein the polymerisation is performed in the presence of a process aid additive selected from at least one of (1) a polysulphone copolymer; (2) a polymeric polyamine or (3) an oil-soluble sulphonic acid.

Abstract: A process for the gas-phase (co-)polymerization of olefins in a fluidized bed reactor using a chromium oxide catalyst. The polymerization is performed in the presence of a process aid additive.

Abstract: A process for the gas-phase (co-)polymerization of olefins in a fluidized bed reactor using a metallocene catalyst in that the polymerization is preformed in the presence of a process aid additive selected from at least one of 1) a polysulfone copolymer, 2) a polymeric polyamine, or 3) an oil-soluble sulfonic acid.

Abstract: A process for the continuous gas-phase (co-)polymerization of olefins in a fluidized bed reactor using a Ziegler-Natta type catalyst. The polymerization is performed in the presence of a process aid additive.

Abstract: A process for the gas-phase (co-)polymerisation of olefins in a fluidised bed reactor using a chromium oxide catalyst. The polymerisation is performed in the presence of a process aid additive.

Abstract: A process for the gas-phase (co-)polymerisation of olefins in a fluidised bed reactor using a metallocene catalyst. The polymerisation is performed in the presence of a process aid additive.

Abstract: A process for the gas phase polymerization of one or more alpha-olefins conducted in the presence of a catalyst in a reactor having a fluidized bed, in which process, one or more zones having a temperature greater than the average bed temperature are formed at or in close proximity to the reactor wall, comprising the step of deactivating said zones by the introduction into the reactor of an effective quantity of carbon monoxide.

Abstract: A continuous gas fluidized bed process for the polymerization of olefin monomer(s) wherein the recycled gaseous stream withdrawn from the reactor is divided into two streams (A and B) and that (a) a first stream (A) having been cooled to a temperature at which liquid condenses out is then reintroduced directly into the fluidized bed in the reactor in such a way that, at any time, the condensed liquid is continuously introduced into the bed at a minimum rate of 10 liters of liquid per cubic meter of fluidized bed material per hour, and (b) a second stream (B), which by-passes the above cooling/condensing step, is passed through an exchanger and is then reintroduced into the reactor. The continuous introduction of a liquid into the reactor reduces or even eliminates fouling problems which can be encountered in conventional gas phase olefin polymerization processes.

Abstract: The invention relates to a process for the production of a semipermeable membrane on a porous conductive support. The process involves the stages of finely dispersing in an aqueous or hydroorganic medium, insoluble solid mineral products in the presence of an electrodepositable coating resin, the preparation of an electrophoresis bath by adjusting the composition of the dispersion, deposition by electrophoresis of a layer of resin-coated, solid mineral products on a porous conductive support, possible deposition of several coatings and heat treatment of the porous conductive support and its layer of electrodeposited solid products. This gives filtering membranes suitable for microfiltration, ultrafiltration and reverse osmosis.