Progress in Technology and Catalysts for Continuous Stirred Tank Reactor Type Slurry Phase Polyethylene Processes

High-density polyethylene (HDPE) have been widely used as materials of hollow molded articles, extrusion molded articles, films and sheets. The properties of HDPE vary depending on its application fields and processing methods thereof. Approximately 50 million tons of HDPE are produced annually around the worldwide by slurry phase processes. In this paper, the status of slurry phase polyethylene processes in China is briefly introduced. Two of the most important licensers of continuous stirred tank reactor (CSTR) type slurry phase polyethylene processes, namely, Hostalen (Licensed by Basell), CX (Licensed by Mitsui), with a dual- or three-reactor are reviewed. The merits and demerits of the examined polyethylene production technologies are discussed in detail. Catalyst is a key of polyolefin technology. It does have an extremely close relationship with the performance of polyethylene. The characteristics and disadvantages of different catalysts for the two processes are summarized for comparison, including the PZ and RZ catalysts of Mitsui, the BCH and BCE catalysts of Beijing Research Institute of Chemical Industry, the TH series catalysts of Basell. Some advices on the development and application of HDPE catalysts for the slurry process are proposed.