Innovative centrifugal airflow upgrading for coal gasification fine slag based on experiment and CFD-DEM approach

In this work, an innovative process combining centrifugal airflow upgrading and sieving was proposed to achieve enrichment of residual carbon. The separation mechanism and macroscopic flow behavior in centrifugal air classifier were explained and predicted by constructing a coupled CFD-DEM model considering particle contact parameters. Compared the grinding, dry sieving pre-treatment had a better promotion effect on the enrichment of residual carbon. The general flow pattern was composed of an upward swirling flow and a horizontal rotation flow, facilitating dispersion and secondary elution of carbon. However, the tangential inlet and horizontally mounted rotor cage were the main cause of secondary vortex formation, leading to severe particle entrainment. Increasing inlet gas velocity at appropriate rotor speed was conducive to obtaining higher carbon content and carbon yield. By regulating the inlet gas velocity and rotor speed, higher carbon content and yield could be achieved at particle size fractions of 78-160 mu m.