FLUID-BED MELT GRANULATION: GROWTH REGIME PREDICTION

VILLA, MARTA; COTABARREN, IVANA; BERTIN, DIEGO; PIÑA, JULIANA; BUCALÁ, VERÓNICA

Sheffield

Congreso; 7th International Granulation Workshop; 2015

Particles Product Group-University of Sheffield

Fluid-bed granulators usually present operating problems due to competition between different growth mechanisms (agglomeration and/or coating). Therefore, it is important to develop tools for predicting the main or dominating size enlargement mechanism for a wide range of operating conditions. From experimental data available for urea melt granulation in a bottom-spray fluidbed system, the feasibility of using dimensionless numbers already proposed in the open literature to predict the growth mechanism was first studied. Even though the Stokes and Flux numbers have been reported to be successful in predicting the dominant growth mechanism for other granulation systems, both were of limited applicability to urea melt granulation. Thereby, for the urea granulation process, a new dimensionless semi-empirical parameter was postulated in order to predict the occurrence of agglomeration in terms of granulator operating variables. The developed approach allowed successfully predicting the formation of agglomerates for a wide range of operating conditions. Consequently, the proposed parameter is of practical utility to determine the compensation that could be implemented in a given operating variable, against a change in another one, in order to ensure the desired growth mechanism.