The ability to control particle size distribution (PSD) is pivotal to the chocolate sector, impacting rheology, thermal stability and cooling contraction. Close control of milled slurries enables product specifications to be met and optimised to maximise desirable effects such as taste and mouthfeel. Many methods of milling exist however the potential for optimisation is limited without better understanding. This project is concerned with stirred ball milling of cocoa liquor slurries whereby modelling and simulation of design and process parameters will increase the processing knowledge and ability to optimise and scale up.
This improved operational understanding will subsequently satisfy green credentials through better process control, reduction of out-of-spec waste and energy efficiency design optimisation. To simulate the flowrate, power consumption and the collision kinetics, model coupling is required. For successful simulation, the Discrete Element Methodology (DEM) will be used in conjunction with Computational Fluid Dynamics (CFD). DEM-CFD will simulate the motion of the stainless-steel grinding media and the cocoa liquor slurry to predict velocities, collision modes, frequency, energy etc which will then enable implementation of comminution population balance models.. These numerical models will be validated through experimental data techniques such as Positron Emission Particle Tracking (PEPT). Furthermore, experimental evaluation of milling efficiency will be conducted at lab and pilot scale for correlation and validation of the population balance kernels.