Computer Simulation of Particle Size Classification in Air Separators

Cement powder size classification efficiency significantly affects quality of final product and extent of energy consumption in clinker grinding circuits. Static and dynamic or high efficiency air separators are being used widely in closed circuit with multi-compartment tube ball mills, High Pressure Grinding Rolls (HPGR) and more recently Vertical Roller Mills (VRM) units in cement plants to classify comminuted clinker particles at finish grinding stage. Therefore, simulation of air separators is of critical importance in order to provide tools that can assist cement plants engineers in their routine clinker grinding circuit optimization efforts. In this paper, Air Separator Simulator (ASSIM), a newly developed simulator implemented in VB™ which provides a user-friendly process analysis and optimization environment will be introduced. First, a review of mathematical modeling of cyclone separators is presented. Then, the details of ASSIM and the results of its testing using industrial data from J. K. White Cement Works plant will be discussed. The simulator is mainly based on the Whiten function to model air separators and predicts fine and coarse output streams particle size distributions and flow rates. ASSIM performance was verified and validated by comparing its outputs with measured data collected around an operating air separator. Preliminary software tests indicate the accuracy and precision of the developed code in predicting various properties of output streams as sum of least squares between predicted results and actual data is less than 0.01.