A new static cyclonic classifier: Flow characteristics, performance evaluation and industrial applications

Due to the low particle classification accuracy or powder production of static air classifiers, a new cyclonic classifier with middle primary and secondary tangential inlets and feed tube was designed. The flow field and classification performance of the lab-scale classifier were investigated numerically and experimentally. The industrial cyclonic classifier's performance was also on-site tested. The simulated results show that the classifier has a main flow characterized by an upper upward vortex and a downer reverse-flow. The secondary air forms the other two vortexes with high tangential velocity near the wall and high axial velocity at the center, which helps to wash the fine particles and accelerate their discharge. The primary and secondary air occupies the separated space with a sharp dynamic boundary in the classifier regardless of inlet air velocity. The experimental lab-scale classifier has a maximum Newton efficiency of 88% with coarse product yield of 92%. The industrial classifier has been used to classify the waste microsilica for the reutilization, which well meets the industrial requirements of the classification efficiency and energy consumption. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.