Abstract: The present invention relates to processes and apparatus useful for the production of polymer powder, and in particular to processes and apparatus for the degassing of polymer powder.

Abstract: Polymerization unit for producing polymer powder having at least one polymerization reactor for the polymerization of light (co)monomer(s) having less than 7 carbon atoms, and heavy comonomer(s) having at least 7 carbon atoms, and a degassing section including two (and optionally a third) cylindrical degassing vessels in series. Light (co)monomer(s) are degassed in the first degassing vessel (V1) and recovered, and heavy comonomers are degassed in the second degassing vessel (V2) and recovered. The active polymer powder is optionally polished and/or optionally deactivated in the optional third degassing vessel (V3). The cross-sectional area (S2) of the second degassing vessel is greater than 1.5 times the cross-sectional area (S1) of the first degassing vessel [S2>1.5×S1], and vessels V1 and V2 are equipped with a vent recovery unit (VR) for respectively recovering the light (co-)monomer(s) (VR1) and the heavy comonomer(s) (VR2) from the gases exiting the vessels.

Abstract: Silica supported catalyst composition useful in olefin polymerization, having a SiO2 content not more than 70 weight %, a transition metal (M) content between 2.5 and 9.1 weight %, a magnesium content between 0.5 and 3.3 weight %, an aluminium content between 0.3 and 5 weight % and a chlorine content between 5 and 30 weight %. The silica support has, prior to addition of catalytically active ingredients, a residual surface hydroxyl content between 0.6 and 2 mmole/g of silica, and the molar ratio of transition metal (M) to magnesium is between 0.3 and 2.5.

Abstract: The present invention relates to processes and apparatus useful for the production of polymer powder, and in particular to processes and apparatus for the degassing of polymer powder.

Abstract: Process for operating a vertical fixed bed degasser which is continuously fed with an active polymer powder produced by a catalytic olefin polymerization process in a polymerization reactor. The polymerization conditions in the degasser are such that there is produced an additional amount of polymer corresponding to between 0.001 and 0.015 times the amount which entered the degasser. The degassing process includes introducing into the degasser a stripping gas containing principal monomer, with the temperature inside the degasser being the polymerization reactor temperature plus or minus 20° C.

Abstract: The present invention provides a new process for preparing a catalyst for the gas phase polymerization of olefins wherein the sequence of addition of the catalyst components and the selection of the said components provides a catalyst composition which exhibits a superior response to hydrogen, a surprisingly high productivity and an improved activity profile. The catalyst consists of compounds of a group IV transition metal, Mg, C1 and A1 supported on a silica support.

Abstract: The present invention relates to a process for operating a vertical fixed bed polymer powder degasser.