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

Abstract: Process for introducing a polymerisation catalyst in solid form into a gas-phase fluidised 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 polymerisation catalyst and a carrier gas are passed through the inner tube into the gas-phase fluidised 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 fluidised 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: The present invention relates to a process for polymerisation in a gas-phase fluidised bed, and in particular to a process for the introduction of a polymerisation catalyst in solid form into a gas-phase fluidised bed, which process comprises using an injection device having an inner tube of internal cross-sectional area of 10 to 100 mm2 and an outer tube forming an annulus around said inner tube with a cross-sectional area of 1 to 10 times the internal cross-sectional area of the inner tube, and passing said polymerisation catalyst and a carrier gas through the inner tube and into the gas-phase fluidised bed at a linear velocity of said carrier gas of 4 to 14 m/s and at a mass flow rate of carrier gas in the range 10-35 kg/h, and passing a shielding gas through the outer tube and into the gas-phase fluidised bed at a linear velocity of said shielding gas of 1 to 10 times the linear velocity of the carrier gas through the inner tube and at a mass flow rate of the shielding gas in the range 100-500 kg/h, where