An approach to measuring and modelling the residence time distribution of cement clinker in vertical roller mills

ABSTRACT This paper presents an experimental approach to measure and model the residence time distribution of vertical roller mill in cement clinker grinding circuit. The dispersion model, tank-in-series model, and a perfect mixer with a bypass model were employed to describe the residence time distribution. A perfect mixer with a bypass model was found to a tolerable fitting to describe the RTD of solids in VRM. The result shows 43% of the fine fraction of fresh feed as an existing bypass without spending adequate time within the VRM. The result also shows that the grinding occurs in 54% of the table surface and about 46% of the table surface can be called the dead zone.