Patent ID: 9260547
Filing Date: 2016-02-16
CPC Classification: C08F

Claim Text:
1. A process for producing ethylene polymers in at least two cascaded polymerization reactors comprising the steps of: polymerizing ethylene in the presence of a polymerization catalyst, hydrogen and optionally one or more alpha-olefin comonomers in a diluent in a first polymerization reactor to produce a first slurry comprising a first ethylene polymer and fluid phase comprising said diluent; withdrawing a first stream of said slurry from said first polymerization reactor; directing said slurry stream into a second polymerization reactor; polymerizing ethylene in the presence of the first ethylene polymer, the polymerization catalyst, hydrogen and optionally one or more alpha-olefin comonomers in a diluent in a second polymerization reactor to produce a second slurry comprising an ethylene polymer mixture and a fluid phase comprising said diluent; withdrawing from said second polymerization reactor a second slurry stream having a solids concentration which is higher than the average solids concentration of the second slurry within the second polymerization reactor; withdrawing from said second polymerization reactor a third slurry stream having a solids concentration which is lower than the average solids concentration of the second slurry within the second polymerization reactor; and directing at least a part of said second slurry stream into one of said first and second polymerization reactor.