Patent ID: 8487053

Claim:
A method for removing polymer skins from reactor walls in a polymerization reactor system comprising a loop slurry reactor, the method comprising: (1) contacting a catalyst system, an olefin monomer, and an olefin comonomer in the loop slurry reactor under polymerization conditions to produce an olefin copolymer; (2) monitoring a process variable in the polymerization reactor system to detect a condition indicative of polymer skin formation on the reactor walls, wherein the condition indicative of polymer skin formation comprises a decrease in heat transfer coefficient, a decrease in slurry circulation velocity, an increase in circulation pump pressure drop, an increase in pump power consumption, or any combination thereof; and (3) in response to the detection of the condition indicative of polymer skin formation on the reactor walls, (a) removing some or all of the olefin comonomer to produce an olefin polymer having a density at least 0.015 g/cc higher than the olefin copolymer density; and (b) increasing a polymerization temperature of the loop slurry reactor by at least 6° C. (11° F.); wherein the method results in an increase in a heat transfer coefficient of the loop slurry reactor of at least 28 W/m 2 /° C. (4.9 BTU/hr/ft 2 /° F.).