MULTI-REACTOR SLURRY POLYMERIZATION PROCESSES WITH HIGH ETHYLENE PURITY

摘要

A slurry polymerization process for the preparation of polyethylene in a reactor cascade of two or more polymerization reactors comprising the steps of feeding to a polymerization reactor amounts of ethylene, of a Ziegler catalyst, of fresh aluminum alkyl and of a diluent; feeding the slurry product withdrawn from the polymerization reactor to a second polymerization reactor; and feeding additional amounts of ethylene and of diluent wherein the ethylene is first passed through an ethylene purification unit, which reduces at least the concentration of carbon monoxide, carbon dioxide, oxygen, acetylene and water contained in the ethylene, before it is fed to the two or more polymerization reactors of the reactor cascade.