LAUSR

ABSTRACT The modern air-based density separator achieves density-based separation for particle sizes greater than 6 mm. Parametric studies, conducted with a modified laboratory-scale unit, operating at an optimal feed rate of 200 kg/hr to upgrade low-rank coal, have demonstrated the applicability to clean finer size fractions up to 1 mm. However, there is a lack of fundamental understanding of the separation process that can be provided utilizing numerical modeling techniques. The separation process was numerically modeled using K-Epsilon and RSM turbulence formulations and validated using experimental dataset. The results prove that the effect of fine coal vortices forming around the riffles act as a transport mechanism for higher density particle movement across the table deck resulting in 43% displacement of the high-density particles to the product side. The velocity and vector plots show high local variances of air speeds and pressure near the feed end and an increase in feed rate results in a drop in the deshaling capability of the table.