Vanessa Düphans, M.Sc.

Contents

Abstract

In the pharmaceutical industry there is a constant demand for the development of new drugs. An important aspect in the production of pharmaceutical products is the formation of a homogeneous mixture of known particle size distribution. For this reason, the unit operation mixing in the individual screw elements of a co-rotating intermeshing twin screw extruder must be quantified [1]. 
 

Description

Twin-Screw-Extrusion offers the advantage that the process combines several unit operations in one apparatus, e.g. mixing or milling. The screws have a modular design with for example conveying, kneading or mixing elements. Through the combination of different unit operations the process is complex and difficult to optimize. Computer based simulations offer the possibility to predict critical process parameters in the extruder [2]. For the characterization of mixing in twin screw extruders it has to be differentiated between distributive and dispersive mixing, where the first process means a homogeneous distribution of the material and the second process describes the breakup of solid particles [3].
The aim of this work is to investigate both types of mixing using simulative and experimental methods. In addition to the dimensionless parameters, which Pawlowski [4] has developed to characterize the pressure and power characteristics of screw elements, dimensionless relationships should be derived to describe the mixing characteristics in specific screw elements.

References

1. Cullen, P. J., Romañach, R. J., Abatzoglou, N., Rielly, C. D.; Pharmaceutical Blending and Mixing, John Wiley & Sons, New Jersey, 2015
2. Kohlgrüber, K.; Modeling: Possibilities and Limitations, in: Co-Rotating Twin Screw Ex-truders: Fundamentals, Technology and Applications (Hrsg: K. Kohlgrüber), Carl Hanser Verlag, München, 2008
3. Kirchhoff, J.; Mixing and Dispersing: Principles, in: Co-Rotating Twin Screw Ex-truders: Fundamentals, Technology and Applications (Hrsg: K. Kohlgrüber), Carl Hanser Verlag, München, 2008
4. Pawlowski, J.; Die Ähnlichkeitstheorie in der physikalisch-technischen Forschung, Springer Verlag, Berlin, 1971

Curriculum Vitae