PROCESS FOR POLYMERISING OLEFIN IN GAS PHASE

摘要

The present invention relates to a process for continuously manufacturing ethylene (co-)polymer in a gaseous phase in a polymerization zone through which passes an essentially gaseous reaction mixture comprising the (co-)monomer(s). In addition the process comprises transferring a mixture (A) formed by the gaseous reaction mixture and the solid (co-)polymer in a depressurization zone, and separating the mixture (A) into a solid phase (B) and a gaseous phase (C) returned into the polymerization zone. The solid phase (B) is subjected to (1) at least one non-deactivating flushing with respect to the active catalytic residues, and subsequently (2) a deactivating flushing with a gaseous mixture of nitrogen, water and oxygen . The (co-)polymer thus obtained has very low contents of unreacted (co-)monomer(s) and volatile organic compounds, and exhibits a high whiteners index and a long thermal stability with time.