Process for transitioning between Ziegler-Natta-based and chromium-based catalysts

摘要

The actualizing scheme of the present invention relates to the method for switching between the polymerization catalyst systems, which includes the method for switching in the olefinic polymerization reaction using the Ziegler-Natta catalyst system and chrome-base catalyst system. The designed actualizing scheme is a method for switching the first catalyst into the second catalyst in the olefinicpolymerization reactor, which includes the following steps: adding the deactivator agent (DA) choosing from carbon monoxide, carbon dioxide and one of their combination into the reactor; adding the catalyst adsorbing agent (CAA) choosing from the silica, oxide of alumina or one of their combination, wherein the first catalyst includes at least one conventional Ziegler-Natta catalyst and cocatalyst, wherein the second catalyst includes at least one chrome-base catalyst, wherein the reactor is a gas-phase fluidized-bed reactor, and the CAA do not include the transitional metal basically. In another actualizing scheme, it designed a method for switching the first catalyst into the second catalyst in the olefinic polymerization reactor, which includes the following steps: adding the transition auxiliary agent(TAA), wherein the TAA is chosen from the alkoxylated amine, the alkoxylated acidamine or one of their combination, wherein the first catalyst includes at least one kind of the materials comprising Ziegler-Natta catalyst, cocatalyst and random carrier which form the catalyst, and the second catalyst includes at least one kind of chrome-base catalyst.