Aspects of Screw Design for Wet Granulation Extrusion
Michael R. Thompson and Junfeng Sun. Dept. of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON L8S4L7, Canada
Wet granulation in a twin screw extruder offers continuous production, scale-ability, excellent mixing, and a high degree of flexibility for controlling the particle growth mechanism. One of the key advantages to this machine is its modular multi-zone construction, where each zone can possess a different shear field and residence time due to the screw elements selected. In order to develop granulation extrusion for industrial use, the mechanism of granulation for each screw element must be understood. This paper discusses a study examining the particle size and particle shape of granulated lactose monohydrate that can be produced by different screw elements in a co-rotating twin-screw extruder. The results presented show that both particle shape and size are unique features for each element type examined.