Patent ID: 7790842

Claim:
A process for the separation of volatile material from particulate polymer discharged from a polymerisation reactor in the form of a polymer slurry, comprising: (a) feeding the particulate polymer which has been substantially freed from unreacted monomer in an earlier separation step using an inert gas to a purge vessel and causing it to move through the vessel in substantially plug-flow mode; (b) heating the particulate polymer in the purge vessel to a temperature greater than 30° C. but insufficiently high to cause the polymer particles to become agglomerated, and/or maintaining the polymer at a temperature in this range in the purge vessel; (c) feeding gas to the purge vessel to remove volatile material therefrom, removing the particulate polymer from the purge vessel; wherein substantially all of the heating of the polymer particles which occurs in the purge vessel is accomplished by preheating the gas fed into the purge vessel, and the polymer slurry discharged from the polymerisation reactor is submitted to a pressure release such that diluent is evaporated and a polyolefin/gas mixture is formed in a collecting vessel, and a concentrator vessel is used between the collecting vessel and the purge vessel.