Patent ID: 8324328

Claim:
A multi-reactor polymerization process for the production of an olefin polymer comprising: a) introducing an olefin monomer, a polymerization catalyst and a diluent carrier liquid into a first reactor of a multi-reactor polymerization system and circulating said diluent liquid and monomer in said first reactor to polymerize said monomer in the presence of said catalyst system to produce a slurry of polymer particles in said diluent carrier liquid; b) introducing an olefin monomer, a polymerization catalyst and a diluent carrier liquid into a second reactor of said multi-reactor polymerization system and circulating said diluent liquid and monomer in said second reactor to polymerize said monomer in the presence of said catalyst system to produce a second slurry of polymer particles in said diluent carrier liquid; c) directing said polymer slurry in said first reactor into a settling leg connected to said first reactor; and d) periodically transferring polymer slurry from said settling leg of said first reactor into a transfer line having a multi-position valve having a first position in which said transfer line is open to an inlet of said second reactor and a second position in which said transfer line is closed to the inlet of said second reactor and open to a flash line providing an exit for the withdrawal of polymer slurry from said process; e) operating said multi-position valve in said transfer line in said first position to provide for a series mode of operation of said first and second reactors or in said second position in which said first and second reactors are operated in a parallel mode of operation; f) directing polymer slurry in said second reactor into a settling leg connected to said second reactor; and g) transferring polymer slurry from said second reactor settling leg into a flash line for withdrawal of polymer slurry from said second reactor.