Abstract: This study presents the results of numerical and experimental simulation of flow pattern in a cyclone separator in sulfur granulation process. For the first time, a cone vortex stabilizer has been used to improve cyclone efficiency. The flow features are examined in terms of flow field, pressure drop, particle trajectories and separation efficiency. In this study, grade efficiencies have been computed and compared with the experimental values for cyclones of different cone stabilizer dimensions. The results show that the separation efficiency rising with the use of the cone stabilizer and the main reason of it is the reduction of particle escaping from cone body of cyclone to upward flow.