Characterisation of High Shear Mixers for Process Intensification

High shear mixers such as rotor-stators, ultrasonicators, high pressure jets, are used for dispersion processes during the manufacture of numerous high value products. These may be in the form of liquid-liquid dispersions (emulsions), a dispersion of fine powder (nanoparticle, nanoclay, graphite dispersions) or three phase systems, for ex. Pickering emulsions. varying from pharmaceuticals, agrochemicals, food, personal care products to paints, lubricants, cosmetics.

The generation of a fine dispersion, i.e. small particle or droplet sizes are essential in achieving the high performance products and the high levels of local energy dissipation rate make such devices suitable for dispersion processes. The product quality depends on both the breakup performance of these devices and the homogeneity achieved within the bulk as breakage would typically occur locally. It is also common to have significant changes in the dispersion rheology during the dispersion process: a highly non-Newtonian behaviour may develop during emulsification or the delamination of layered structures or the pre-dispersion rheology, i.e. prior to deagglomeration may be complex.

This would have severe effects on the overall bulk flow and hence homogeneity. Scale up is another challenge. This project will aim to study the flow and power characteristics of high shear mixers.

The study will build on the previous work of the supervisor and make use of bench scale high shear process devices- a selection of rotor-stator designs and an ultrasonicator- in both batch and re-circulation mode. The objectives will be to establish the flow and power characteristics of such devices in liquids of a range of rheological properties and how the flow established may have an effect on dispersion processes, demonstrating this with case studies of emulsification and deagglomeration. The knowledge developed will provide guidelines for industrial practice applicable to a wide range of products.

You will have the opportunity to make use of a range of devices and analytical techniques. The knowledge and skills developed should enhance your employability in a wide range of industries. It is anticipated that there will be the opportunity to present and discuss findings during international conferences and also network with other researchers in the field.

For further information, contact Dr Nerime Gül Özcan-Taşkın. Selected related publications: Utomo, A.; Alderman, N.; Pardon, G.A.; Özcan-Taşkın, N. G.

(2023) A Comparative Study on Emulsification in the Presence of a Nanoclay (Pickering emulsion) or a Surfactant Using High Intensity Mixing. Accepted for publication in Chem Eng Res Des. Hannam, A, Sparks, T, Ozcan-Taskin, G (2021) Power characteristics of inline rotor-stators with different head designs, Chemical and Process Engineering, 42(2), pp.91-104, ISSN: 0208-6425.

DOI: 10.24425/cpe.2021.137343. Yu, H.; Tsokataridou, S.; Parsons, K.; Grenville, R.; Kehn, R.; Rielly, C.D.; Özcan-Taşkın, N.G. (20