Process for start-up of a polymerisation reaction fluidised bed

Abstract

Process for polymerization and, in particular, to a process for start-up of a gas phase fluidized bed polymerization reaction involving one or more monomers using a catalyst in a reactor. The process includes providing a start-up bed of particles in the reactor in the presence of the one or more monomers but in the absence of the catalyst, introducing at Tcatalyst to the reactor to initiate reaction and start-up polymer production at a time T, Tbeing between 1 and 6 hours after T. The value of Xis less than a threshold value, wherein: X=Cumulative production in the time period Tto T/(Cumulative catalyst injection the time period Tto T*PC), where PCis the ethylene partial pressure in the reactor at the time T, subsequently stopping the injection of catalyst, and taking a corrective action to address the low value of X.