Numerical Experiment on Gas-Solid Two-Phase Flow of Granulation Process in Stirred Vessel (Clarification of Reason Why Double Peaks in Diameter Distribution of Produced Particles Appear)

Granulation is generally performed in a stirred vessel, by spraying binders onto row materials stirring the particles. However, the conventional granulation system has some problems. First, there are double peaks in the particle diameter distribution that degrade the quality of final products. Second, it takes too long time to determine the operating and producing conditions for a desired particle diameter distribution. Therefore, it is required for us to sophisticatedly control a granulation process in a stirred vessel with aid of computer simulations. In the present study, we carry out numerical experiments of granulation processes in a simplified stirred vessel to clarify the reason why double peaks in the particle diameter distribution appear. Through the study, it is confirmed that the particle diameter distribution approaches to an asymptotic state at the final stage of granulation, and the double peaks are generated by the statistical destruction of large particles.