Abstract: A setting leg for a polymerization reactor connected to the lower part of the loop reactor (1). A conduit (2) is welded to the loop reactor and leads to upper valve (3) and lower block valve (4). Downstream of the lower block valve (4) is a further conduit (5) which leads to a lower region (6) and to a product take off (PTO) valve 7. Conduit (5) has a significantly greater cross-sectional area than conduit (2). In use, the block valves (3) and (4) are always open to allow slurry from the reactor loop to enter the settling leg. The PTO valve (7) is regularly opened to allow the settled polyethylene “fluff” to be rapidly expelled along conduit (8). The greater area of conduit (5) significantly increases the settling rate ad polymer concentration of the polyethylene “fluff”.

Abstract: A setting leg for a polymerisation reactor connected to the lower part of the loop reactor (1). A conduit (2) is welded to the loop reactor and leads to upper valve (3) and lower block valve (4). Downstream of the lower block valve (4) is a further conduit (5) which leads to a lower region (6) and to a product take off (PTO) valve 7. Conduit (5) has a significantly greater cross-sectional area than conduit (2). In use, the block valves (3) and (4) are always open to allow slurry from the reactor loop to enter the settling leg. The PTO valve (7) is regularly opened to allow the settled polyethylene “fluff” to be rapidly expelled along conduit (8). The greater area of conduit (5) significantly increases the settling rate ad polymer concentration of the polyethylene “fluff”.

Abstract: A method for transitioning between two different catalysts in olefin polymerizations, a first catalyst and a second catalyst, comprising the steps of: discontinuing the feed of the first catalyst into the polymerization reactor, and introducing the second catalyst into the reactor, wherein the transition is performed between a chromium-based catalyst and a metallocene catalyst.