Method for Making a Transition between Polymer Grades
The present invention relates to a method of transition between polymer grades in a polymerisation process comprising polymerising at least one monomer in at least a first reactor and a second reactor connected to each other in series, wherein the monomer feed in the first reactor is maintained essentially constant during the transition.
1 - 8 . (canceled)
9 . A method of transition between polyolefin grades in a polymerisation process comprising:
polymerising at least one monomer in at least a first reactor and a second reactor connected to each other in series, wherein olefin monomer is fed into the first reactor at an essentially constant rate during a transition between the first reactor and the second reactor.
10 . The method of claim 9 , wherein the olefin monomer comprises ethylene.
11 . The method of claim 9 , wherein the first reactor and the second reactor comprise loop reactors.
12 . The method of claim 9 , wherein the feed of monomer into the first reactor is changed by at most 5% in relation to an average monomer feed in the first reactor of the transition during the transition.
13 . The method of claim 9 , wherein the feed of monomer into the first reactor is changed by at most 2% in relation to an average monomer feed in the first reactor of the transition during the transition.
14 . The method of claim 9 , wherein the polymerization occurs in the presence of a Ziegler-Natta catalyst.