Cyclone separators are used extensively to classify mineral slurries with a size or density distribution in the mineral and coal industries. In Cyclone it is very important to accurately determine the back pressure (pressure drop) and particle separation efficiency across Cyclone. CFD helps in determining these parameters by closely simulating continuous phase (ex. flue gas) and discrete phase (ex. ash particles) flow within the Cyclone. Cyclone analysis becomes more complex due to presence of tube bundle on upstream side of Cyclone entry and in presence of these tube bundles it is very important to predict accurate velocity profile at Cyclone entry which can be achieved in CFD
CFD analysis of the cyclone separator was carried for determining pressure drop, particle trajectory and particle separation efficiency of Cyclone. Initially continuous phase simulation were carried out for determining pressure drop across Cyclone by properly considering the direction resistance of tube bundles. Available particle size data was used in appropriate way to define particle size distribution in CFD. Appropriate values of restitution coefficient were selected for accurate modeling of particle trajectory. Particle trajectory and particle separation efficiency were observed for various sizes of particles. Based on initial results, design modifications were carried out in Cyclone upstream side converging duct and within Cyclone duct for reducing the pressure drop across cyclone, improving the particle separation efficiency. This modification has also helped in reducing the erosion rate of Cyclone duct wall which was happening due to concentration of large dimeter particles at one particular region of Cyclone duct wall.