A reduced efficiency approach-based process model for a circulating air classifier

The performance of a circulating air classifier has been studied systematically by conducting experiments over a range of process and design variables. It is found that while the overall induced flow rate is proportional to the speed of rotation of the wheel, the circulation pattern inside the classifier depends on the configuration of stationary guide vanes. This is found to have a significant effect on the range of operability of the classifier. Results show that the cut size, sharpness of separation and the bottom and top size selectivity increments are influenced strongly by the stationary guide vane configuration. Using experimental data from a dense material (fly ash) and a light material (rice husk), a model based on the reduced efficiency curve approach, originally proposed for hydrocyclones, has been developed to predict the performance of the classifier.