Patent ID: 7524904

Claim:
A process for slurry polymerization and for separating hydrocarbon fluid from solid polymer particles and purge gas, the process comprising: polymerizing in a reaction zone at least one olefin monomer to produce a slurry comprising solid polymer particles and hydrocarbon fluid; withdrawing a portion of the slurry from the reaction zone; separating at least a majority of the hydrocarbon fluid from the solid polymer particles in an intermediate pressure zone as a vaporized hydrocarbon fluid stream; condensing the vaporized hydrocarbon fluid stream in a condensing zone, whereby a condensed hydrocarbon fluid stream is formed; transferring the solid polymer particles from the intermediate pressure zone to a purge zone in which a purge gas is passed through the solid polymer particles to remove entrained hydrocarbon fluid, thereby forming a mixed stream containing hydrocarbon vapor and purge gas; transferring the mixed stream to a recovery zone where the purge gas and hydrocarbon fluid are separated to form a recovered purge gas stream and a recovered hydrocarbon fluid stream; passing at least a first portion of the recovered purge gas stream from the recovery zone to the purge zone; passing at least a first portion of the recovered hydrocarbon fluid stream from the recovery zone to a fractionation zone; passing a second portion of the recovered hydrocarbon fluid stream from the recovery zone to a recycle zone; transferring the condensed hydrocarbon fluid stream from the condensing zone to the recycle zone; and transferring at least a majority of the condensed hydrocarbon fluid in the recycle zone to the reaction zone without fractionating the condensed hydrocarbon fluid.