Design and optimisation of mini-hydrocyclones for the separation of particles in the micron size range

Abstract

The use of mini-hydrocyclones (e.g. 10 mm in diameter) for the separation of par-ticles in the micron range is of growing interest in industry. However, these hydro-cyclones are typically limited to conventional shapes or restricted to specific outletsizes, which can lead to sub-optimal performance. Mini-hydrocyclones exhibit abypass fraction that is larger than the water recovery, resulting in a high particlerecovery to the underflow, as well as low water recovery, which is convenient fordewatering processes. However, this larger bypass fraction can be a disadvantagewhen the purpose of the hydrocyclone is particle classification, because of the largeamount of fine particles that are misplaced in the underflow. Therefore, a deeperunderstanding of the mini-hydrocyclones performance is needed.The aim of this thesis is to present a method for the optimisation of mini-hydrocyclonedesign. The method consists of designing and 3D printing mini-hydrocyclones, car-rying out Computational Fluid Dynamics (CFD) simulations, and performing ex-perimental tests. 3D printed mini-hydrocyclones were tested and the effect thatchanges in vortex finder and spigot diameters have on separation performance wasstudied. A CFD model was implemented and validated with experimental data formini-hydrocyclones applied to dewatering and classification processes. Lastly, noveldesign of hydrocyclones (i.e. with parabolic walls) were studied in a full factorialand Central Composite Rotatable (CCRD) designs.The first outcome of this thesis is the application of the 3D printing technologyfor practical and rapid prototyping of mini-hydrocyclones. The second outcome isthe implementation of a validated CFD model to predict the performance of mini-hydrocyclone for dewatering and particle classification processes. The third outcomeis the combination of 3D printing technology and the CFD model to evaluate hydro-cyclones with parabolic walls. This thesis demonstrates the potential of 3D printing,CFD modelling and robust experimental testwork to improve the understanding ofmini-hydrocyclones performance in dewatering and classification processes.