Abstract: The extrusion equipment in Chinese domestic polyolefin plants is dominated by twin screw extruders which are categorized as two types in actual application: wholly intermeshing co-rotating type and non-intermeshing counter-rotating type. Currently, in most domestic projects, the extruders are still imported from abroad from three main manufacturers including Coperion GmbH from Germany, the Japan Steel Works, Ltd. and Kobe Steel Ltd. from Japan. The different origin leads to a variety of characteristics. This paper summarizes the technological development of twin screw extrusion equipment from the aforementioned three main manufacturers by starting with the oldest non-meshing anisotropic rotary twin-screw extruders. It reviews the application of melt gear pump in detail and briefly analyzes the relationship between gear pump application and energy consumption. Meanwhile, the paper gives a general introduction to the main technical data, such as production and power of main drive, and compares the stability between the two types of the units with the actual application of full-density polyethylene plant as an example. Moreover, combined with previous project experience, the wear between extruder screws and barrels is introduced and analyzed so as to provide assistance to users in selecting well-designed extrusion equipment with better cost performance.

Key words: polymer processing, twin screw, extrusion, technology development