Optimisation of the performance of a new vertical roller mill by computational fluid dynamics simulations

The performance of two new Vertical Roller Mills (VRM) has been analysed using Computational Fluid Dynamics (CFD). The results show notable air ingress from the bottom of the mill, due to moving components in the mill. This is detrimental to mill performance as the milled powder gets recirculated back into the milling region and reduces the overall milling efficiency. Optimisation of the mill design has been carried out based on CFD modelling results. Proposed reconfigurations produce a positive pressure upstream, suppressing air ingress. Design modifications were implemented in a pilot-scale mill, resolving the air ingress problem. Additionally, erosion patterns were computed for the mill geometry and qualitatively confirmed by visual inspection of the mill.