Process for a gas phase olefin polymerization

The present invention relates to a process for introducing a solid catalyst into a gas-phase olefin polymerization reactor. It comprises in particular storing the catalyst in the form of a dry powder in a hopper, withdrawing from the hopper a measured amount of the said catalyst, introducing the said amount of the catalyst and a liquid hydrocarbon into a mixing chamber, mixing the said catalyst with the said liquid hydrocarbon so as to form in the said chamber a suspension of the entrained catalyst with the said liquid hydrocarbon, and introducing the said suspension into the said reactor. In a preferred form, the liquid hydrocarbon is continuously introduced into the chamber and forms a continuous stream to which is added the measured amount of the catalyst and which flows into the reactor.