Chromium catalysts for olefin polymerization

摘要

Mineral oil is added to a supported chromium catalyst in amounts which maintain a free flowing particulate material. Chromium catalysts so treated, provide polyethylene in a gas phase ethylene polymerization process with reduced reactor fouling or static.

主权项

1. A process for making polyethylene by polymerizing ethylene, optionally with one or more alpha olefins, in a gas phase reactor, the process comprising:
a) forming a solid polymerization catalyst by adding mineral oil to a supported chromium catalyst, provided that the mineral oil is added in amounts less than that required to form a slurry of the supported chromium catalyst in the mineral oil; and b) feeding the solid polymerization catalyst into the gas phase reactor using a dry catalyst feeder; wherein the supported chromium catalyst is supported on silica.