| Abstract: | An innovative way to increase the overall efficiency of a cyclone is presented. By recycling a fraction of the output stream to the inlet duct, the efficiency of the cyclone can be improved. Experiments were conducted using bench scale (0.1 m diameter) and pilot scale (0.456 m diameter) cyclones. The overall efficiency was evaluated for both cyclones at different ranges of recycle ratios. In the presence of the recycle stream, the efficiency increases in a monotonic manner. It may approach 100 % with the use of very high recycle ratios, provided that there is agglomeration of the fine particles available in the feed stream and/or adhesion of fines to the coarse particles. From the experimental results, it is observed that the agglomeration of fine particles is the most important factor for improving the cyclone efficiency by use of a recycle stream. Moreover, the effect of the recycle stream persists, even if the inlet velocity surpasses the saltation velocity of the cyclone. |
