Application of CFD and breakage modelling for predicting the size reduction of protein precipitates during transport

Particle breakage due to fluid flow through various geometries can have a major influence on the performance of particle/fluid transport and separation processes. Whey protein precipitate dispersions were used as a case study to investigate the effect of flow intensity and exposure time on the breakage of precipitates during transport. Computational fluid dynamic (CFD) simulations were performed to evaluate the turbulent energy dissipation rate (ɛ) and associated exposure time along various flow geometries. A breakage model, incorporating the CFD output and experimentally determined parameter values, was found to provide a satisfactory capability for predicting the breakage of the protein precipitate particles. The breakage modelling approach was then applied to particles formed under different agitation intensities during the precipitation process. The formation history of the precipitates had a significant effect on their structure and strength and hence different breakage rates were observed. The precipitate dispersions were propelled through a number of different geometries such as bends, tees and elbows. The shape of the flow geometry was found to have an important effect on particle size reduction. This predictive particle breakage modelling approach was then applied to larger-scale flow geometries with cross-sectional area of 150 times greater than the experimental.