Method and apparatus for preparing and supplying catalyst slurry to a polymerization reactor

A system for supplying a polymerization catalyst to a polymerization reactor comprising:

• a) at least two storage vessels adapted to contain a concentrated catalyst slurry;
• each of said storage vessels having an inlet line adapted to receive a concentrated slurry of catalyst particles;
• b) slurry conduits extending from each of said storage vessels to a mixing vessel and provided with metering valves to control the flow rate of catalyst slurry to said mixing vessel;
• c) a transfer conduit extending from said mixing vessel to said polymerization reactor;
• d) a diluent line connected to said transfer conduit for supplying diluent to said transfer conduit;
• and
• e) a dump vessel adapted to receive catalyst waste and an input line to said dump vessel extending from at least one of said mixing vessel and said slurry transfer conduits.

A method for supplying a catalyst to an ethylene loop polymerization reactor comprising:

• a) providing a concentrated slurry of olefin polymerization catalyst particles in a storage vessel;
• b) supplying said concentrated catalyst slurry from said storage vessel through a slurry conduit to a mixing vessel;
• c) adding a diluent liquid to said concentrated catalyst slurry in order to provide a diluted catalyst slurry in said mixing vessel;
• d) withdrawing said diluted catalyst slurry from said mixing vessel and supplying said diluted catalyst slurry through a transfer conduit to a slurry loop polymerization reactor in which ethylene is polymerized;
• e) mixing a cocatalyst with said diluted catalyst slurry prior to supplying said diluted catalyst slurry to said slurry loop polymerization reactor;
• and
• f) subsequent to the mixing of said cocatalyst with said diluted catalyst slurry passing said diluted catalyst slurry containing said cocatalyst through a section of said transfer conduit to provide for an increased contact time of said cocatalyst with said dilute catalyst slurry prior to the introduction of said catalyst slurry into said polymerization reactor.