Abstract: A supported polymerisation catalyst system comprises: (a) a polymerisation catalyst, (b) a cocatalyst, and (c) a porous support, and is characterised in that the porous support has been pretreated with (i) a chemical dehydration agent and (ii) a hydroxy compound wherein the hydroxy compound is not a cocatalyst or component thereof. The preferred polymerisation catalyst is a transition metal compound for example a metallocene and by use of the supported catalyst systems improved activity may be achieved.

Abstract: The present invention relates to a process for polymerization of olefins, in particular gas phase polymerization of olefins, with the aid of a supported chromium oxide based catalyst.

Abstract: Process for the gas-phase polymerization of olefins in a fluidized bed reactor, by a) passing a fluidizing gas containing an olefin monomer through a fluidized bed of polymer particles in the presence of a polymerization catalyst, b) withdrawing a first gaseous stream containing solid particles from the reactor, c) passing the first gaseous stream to a gas/solids separator, separating solid particles, and forming a second gaseous stream containing residual solid particles, d) passing a portion of the second gaseous stream to a heat exchanger(s) to remove heat and e) recycling a portion of the cooled stream from (d) as the fluidizing gas in (a). The fouling rate of the heat exchanger (s) is such that i) the increase in pressure drop across the heat exchanger is equivalent to less than 5%/year, and/or ii) the decrease in heat transfer of the heat exchanger is equivalent to less than 5%/year.

Abstract: Process for the continuous transition between two different and compatible polymerization catalysts.

Abstract: Process for gas phase polymerization of olefins in a fluidized bed reactor by (a) passing a fluidizing gas containing at least one olefin monomer through a fluidized bed of polymer particles in the presence of a polymerization catalyst to produce polymer at a polymer production rate of C Tonnes/hour, (b) withdrawing a first gaseous stream containing solid particles from the top of the reactor, (c) passing the first gaseous stream to a gas/solids separator, separating solid particles therefrom, and forming a second gaseous stream containing residual solid particles, (d) passing a portion of the second gaseous stream to at least one heat exchanger to remove heat of reaction whereby residual solid particles contact the heat exchanger, and (e) recycling a portion of the cooled stream from step (d) as the fluidizing gas in step (a). The heat exchangers have a heat exchange surface area which totals less than 120×C m2.

Abstract: Process for maintaining a continuous gas-phase (co-) polymerization of olefins in a large fluidized bed reactor in a homogeneous mode while operating at high space time yield and condensation rate in the presence of a polymerization catalyst.

Abstract: Process for the transition between an ethylene co-polymerization process in a polymerization reactor in the presence of a catalyst and of ethylene E and an olefin co-monomer A to produce an ethylene copolymer PEA into an ethylene co-polymerization process carried out in the same polymerization reactor in the presence of a catalyst and of ethylene E and an olefin co-monomer B to produce an ethylene copolymer PEB. Co-monomers A and B are different and are both present in the reactor during at least part of the transition from PEA to PEB. The transition is performed continuously by (i) starting the transition by stopping steady state production of ethylene copolymer PEA and (ii) ending the transition when steady state production of ethylene copolymer PEB is achieved.

Abstract: The present invention relates to a chromium catalyzed ethylene copolymer powder exhibiting a superior fragmentation coefficient.

Abstract: A copolymer of ethylene and an alpha-olefin, said copolymer having a (a) density>0.930 g/cm3, (b) melt index (g/10 min)>4, (c) molecular weight distribution (MWD)>3.0, and (d) FNCT>250 hours, and is described suitable for use in rotomolding applications. In particular the novel copolymers result in improved impact strength, improved permeation resistance and improved environmental stress crack resistance and may suitably be prepared by use of metallocene catalysts.

Abstract: Process for the gas phase polymerization of olefins, in particular, with recycle of fines to the reaction zone. The process includes (a) polymerizing an olefin in a reaction zone in which a bed of polymer particles is maintained in an agitated state by passing a fluid stream through the bed, (b) withdrawing the fluid stream from the reactor after it has passed through the bed of polymer particles, (c) separating entrained solids from the withdrawn fluid stream, and (d) returning the separated entrained solids to the reaction zone. The polymer production rate of the process is at least 40 tonnes/hour, and the separated solids from step (c) are returned to the lower half of the bed of polymer particles in the reaction zone.

Abstract: Copolymer of ethylene and an alpha-olefin, having a density>0.930 g/cm3,melt index (g/10 min)>4, molecular weight distribution (MWD)>3.0, and FNCT>250 hours. The copolymer is suitable for use in rotomolding applications. The copolymer possesses improved impact strength, improved permeation resistance and improved environmental stress crack resistance and may suitably be prepared by use of metallocene catalysts.

Abstract: Process for producing C2+ alcohols from a methane-containing feedstock, by passing the methane-containing feedstock and CO2 to a non-oxidative reforming process to produce a product stream containing CO, H2 and CO2, optionally in the presence of steam, provided that where steam is present in the feed to the reforming process, the steam and CO2 are present in a molar ratio of less than 5:1. The CO, H2 and CO2 stream is passed to a bacterial fermentation step where it is converted to a liquid product stream containing one or more C2+ alcohols and a gaseous product stream containing CO, H2 and CO2. The fermentation step is operated to provide a conversion of CO of at least 60%. CO, H2 and CO2 are recycled from the gaseous product stream to the reforming process such that the H2 reacts with carbon dioxide in the reforming process.

Abstract: Activating supports may be suitably prepared by the following procedure (a) providing a porous mineral oxide support material, (b) treating the support with a phosphorus-containing compound, (c) treating the support from step (b) with an organometallic compound, (d) heating the functionalized support from step (c) under an inert gas and then under an atmosphere comprising oxygen, (e) fluorinating the support with a fluorinating agent, and (f) recovering an activating support. The activating supports are suitable used in combination with single site catalysts for the polymerization of olefins. The supports are most preferably used in combination with metallocene complexes. The preparative route for the activating supports provides for supported polymerization catalyst systems having excellent activities.

Abstract: Process for the activation of a supported chromium oxide based catalyst in a fluidized bed activation reactor which has a catalyst bed being fluidized by a fluidization gas. The activation includes treatment at temperatures above 500° C., in which in an initial stage, where there is an initial temperature increase, the fluidization velocity (Vf1) of the fluidization gas is maintained below 6.5 centimeters per second (cm/sec) until the temperature inside the activation reactor reaches at least 200° C., and the fluidization gas is then brought to a value (Vf2) which is at least 1 cm/sec higher than Vf1.

Abstract: Process for extrusion of polymer by feeding a polymer feedstock to the feed port of an extruder having (i) two or more barrel sections arranged sequentially from (a) an upstream feed barrel section to which polymer feedstock to be extruded is fed, the upstream feed barrel section containing two screws each having a diameter of X, to (b) a downstream barrel section from which melted polymer is passed to a die and extruded, and (ii) a feed port for feeding polymer feedstock to be extruded into the extruder at its upstream end. The polymer feedstock is in the form of a powder, and the feed port area is a rectangular shape with width limited by the width of the upstream feed barrel section to 2*X and with a length greater than 2.5*X. The total area of the feed ports through which polymer feedstock is introduced is greater than 5*X2.

Abstract: The present invention relates to production of polymer, and in particular provides an interlock for use in a process for production of a polymer in a reactor, which process comprises: a. polymerising a monomer and optionally a comonomer in the reactor to produce polymer, optionally in the presence of an inert hydrocarbon, and b. withdrawing produced polymer from the reactor, said interlock being based on the temperature in the reactor, and comprising: 1. measuring the temperature in the reactor or a temperature representative of the temperature in the reactor, and 2. comparing said measured temperature to a threshold temperature, said interlock being characterized in that withdrawal is allowed if the measured temperature is greater than the threshold temperature but is prevented if the measured temperature is lower than the threshold temperature.

Abstract: Process for introducing a polymerization catalyst in solid form into a gas-phase fluidized bed using an injection device having an inner tube of internal cross-sectional area of 10-100 mm2 and an outer tube forming an annulus around the inner tube with a cross-sectional area of 1-10 times the internal cross-sectional area of the inner tube. The polymerization catalyst and a carrier gas are passed through the inner tube into the gas-phase fluidized bed at a carrier gas linear velocity of 4-14 m/s and a carrier gas mass flow rate of 10-35 kg/h. A shielding gas is passed through the outer tube and into the gas-phase fluidized bed at a shielding gas linear velocity of 1-10 times the linear velocity of the carrier gas through the inner tube and at a shielding gas mass flow rate of 100-500 kg/h. No cooled recycle process gas is provided to the injection device.

Abstract: Apparatus and process for gas phase polymerisation of olefins. The apparatus includes (a) a reaction zone having a grid at its base, (b) an inlet located in the lower half of the reaction zone for introducing a reaction gas to the reaction zone, (c) an outlet located in the upper half of the reaction zone for removing the reaction gas from the reaction zone, and (d) a solids separation unit having an inlet fluidly connected to the outlet for removing the reaction gas from the reaction zone. The inlet of the solids separation unit is located at a vertical height lower than the outlet for removal of reaction gas from the reaction zone and such that the angle to the horizontal of a straight line drawn between the inlet of the solids separation unit and the outlet for removal of reaction gas from the reaction zone is greater than 20°.