| 摘要 |
The present invention relates to a process for polymerisation, and, in particular, to a process for start-up of a gas phase fluidised bed polymerisation reaction, said reaction comprising polymerisation of one or more monomers using a catalyst in a reactor, and said process comprising:
a) 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,
b) introducing catalyst to the reactor to initiate reaction and start-up polymer, production, said introduction being designated as time To,
c) at a time T i , T i being between 1 and 6 hours after T 0 , the value of X i is less than a threshold value, wherein: X i = Cumulative production in the time period T 0 �¢ to T i Cumulative catalyst injection the time period T 0 �¢ to T i * P i �¢ C 2 = ,
P i C 2= being the ethylene partial pressure in the reactor at the time T i ,
d) subsequently stopping the injection of catalyst,
e) taking a corrective action to address the low value of X i .
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